AN IN VIVO STUDY COMPARING THE NICKEL AND
CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL
AND SELF-LIGATING METAL BRACKETS
By
Dr. SURISETTY SAI PRIYA
(19200105005D)
A Dissertation Submitted to the
Kaloji Narayana Rao University of Health Sciences,
Warangal, Telangana.
In partial fulfillment
of the requirements for the degree of
MASTER OF DENTAL SURGERY
IN
ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS
Under the guidance of
Dr. SRIKANTH ARYASRI, MDS
READER
DEPARTMENT OF ORTHODONTICS & DENTOFACIAL ORTHOPEDICS
PANINEEYA MAHAVIDYALAYA INSTITUTE OF
DENTAL SCIENCES AND
RESEARCH CENTRE, HYDERABAD
2019-2022
ACKNOWLEDGEMENTS
To begin with I would express my deep affection and love
to my family who has been the most supportive and always stood
by my side throughout my life. I shall forever be indebted to them.
I would like to offer my thanks to the most merciful and
compassionate God Almighty who educates us through our
deceptions and mistakes and showers his blessings on us.
I would like to express my deepest gratitude to my
esteemed Guide Dr. SRIKANTH ARYASRI, Reader in the
Department of Orthodontics & Dentofacial Orthopedics, for his
remarkable help, valuable and constructive advice in times of
need that has made this study possible.
I would like to thank Dr. G. Chandra Sekhar, Professor &
HOD in the Department of orthodontics & Dentofacial
orthopedics, for his constant support and help throughout.
Words are inadequate to express my immense gratitude
to Dr. Ranjit Manne Professor, Dr. P.B.V.N. Swaroopa Rani
Reader, Dr. Shivaram Senior lecturer and Dr. Hanish Anand
Senior lecturer, Dr. Sowmya Senior lecturer for their timely
support.
I extend my sincere thanks to Dr. P. Karunakar Principal, Panineeya
Mahavidyalaya Institute of Dental Sciences & Research Centre, Mr. T.S
Kohli
Chairman,
Mr.
G.S.
Kohli
Vice
Chaiman,
Panineeya
Mahavidyalaya Institute of Dental Sciences & Research Centre,
Hyderabad for their kind support during my study.
I convey my gratitude to all my post graduate colleagues, Dr.
Sowmya, Dr. Tejaswi, Dr. Jyothirmai, Dr. Mownica, Dr. Deepali
Jain, Dr. Vishishta, Dr. komal Rawal, Dr. Siva kalyani, Dr. Sirisha,
Dr. Anusha, Dr. Tanmayi, Dr. Praveen, Dr. Sunayana, Dr. Murali
krishna for their support and timely help.
I would also like to thank Dr. Mohan Raju (Biostatistician) for analyzing
the results and compiling the statistical data for this study.
Finally, I would like to thank many people who have stayed behind the
scenesscenes but have made a significant contribution to this study.
Thank you.
ABBREVIATIONS
SLB
Self-Ligating Bracket
Ni
Nickel
Cr
Chromium
Mo
Molybdenum
Fe
Iron
Ti
Titanium
Co
Cobalt
AAS
Atomic absorption spectroscopy
Ppb
Parts per billion
ICP-MS
Inductively coupled plasma mass spectrometry
NiTi
Nickel Titanium
TABLE OF CONTENTS
S. No.
CONTENTS
PAGE. No.
1
INTRODUCTION
1-4
2
AIMS AND OBJECTIVES
5
3
REVIEW OF LITERTURE
6-22
4
MATERIALS AND METHODS
23-32
6
RESULTS
33-47
7
DISCUSSION
48-68
8
SUMMARY AND
CONCLUSION
69
9
REFERENCES
70-82
10
ANNEXURES
82-87
83-88
LIST OF FIGURES
S.NO.
FIGURES
PAGE
NO.
1
Fig 1: Flow chart of sample distribution
23
2
25
Fig 2: Ormco conventional metal Brackets (MBT
prescription - 0.22” slot)
3
Fig 3: Damon™ Q self - ligating metal
Brackets(Damon prescription - 0.22” slot)
25
4
Fig 4: Storage of hair sample
26
5
Fig 5: Storage of nail samples
6
27
28
Fig: 6 interdental brushes for the collection of oral
mucosa samples
Fig 7: Phosphate buffered saline solution for storage
7
28
of oral mucosa cells
8
Fig 8: Polypropylene tubes for
storage of oral mucosa cells
28
9
Fig 9: Storage of
samples
29
10
Fig 10: Graphite furnace atomic absorption
spectrometer
31
LIST OF TABLES
S.NO.
1
TABLES
PAGE NO.
Various levels at which the nickel and chromium ions are
32
detected
Comparison of nickel concentration in nail samples before and
2
after the treatment in Group A
Comparison of nickel concentration in nail samples before and
3
34
35
after the treatment in Group B
Comparison of chromium concentration in nail samples before
4
and after the treatment in Group A
35
Comparison of chromium concentration in nail samples before
5
and after the treatment in Group B
36
Comparison of nickel concentration in hair samples
6
before and after the treatment in Group A
37
Comparison of nickel concentration in hair samples before and
7
after the treatment in Group B
37
Comparison of chromium concentration in hair samples before
8
and after the treatment in Group A
38
9
Comparison of chromium concentration in hair samples
39
before and after the treatment in Group B
10
Comparison of nickel concentration in oral mucosa
samples before and after the treatment in Group A
11
Comparison of nickel concentration in oral mucosa
39
40
samples before and after the treatment in Group B
12
13
Inter group comparison of nickel concentration
Comparison of chromium concentration in oral mucosa
samples before and after the treatment in Group A
14
41
42
Comparison of chromium concentration in oral mucosa
samples before and after the treatment in Group B
42
15
Inter group comparison of chromium concentration
43
16
Correlation between age and nickel and chromium
44
concentration
17
Inter gender comparison of nickel concentration in various
45
locations
18
Inter gender comparison of chromium concentration in
46
various locations
19
The metal Composition of different stainlesssteel grades
50
20
composition of 316L austenitic type of Stainless steel
51
LIST OF GRAPHS
S.NO.
GRAPHS
PAGE NO.
1
Inter Group comparison of nickel concentration
41
2
Inter Group comparison of chromium concentration
44
3
Mean concentration of nickel among gender
46
Mean concentration of chromium among gender
4
47
INTRODUCTION
Introduction
INTRODUCTION
Self-ligating brackets have been gaining popularity in past few decades.
Self-ligation, on the other hand, is not a novel concept. Stolzenberg created the
Russell attachment, the first self-ligating bracket, in the early 1930s. It did not garner
much popularity, either due to mistrust in the orthodontic community at the time, or
lack of promotion. With the emergence of several varieties of self-ligating systems
during the last several decades, interest in self-ligating brackets has been reignited.
Many advantages have been offered for these self-ligating brackets over traditional
edgewise brackets1.
In order to secure the arch wire to the bracket, SLB’s utilise a "trap door."
They feature a metal labial face integrated into them that can be opened and closed.
Self-ligating brackets are classified as active, passive and interactive based on the clip
that holds the arch wire in place in the bracket slot. Hence, the arch wire is held in
place using these brackets without the need of ligatures. Several self-ligating bracket
designs have arisen, each aiming for the optimal balance of friction and control. When
closed using a "closing door", the bracket opening transforms an open-sided slot into
a rectangular tube. Another design uses a spring clip to completely seat the arch wire
while keeping the clip in touch with it. The assertion that self-ligating brackets have
less friction than conventional brackets is frequently highlighted as a main benefit
which in turn depends on the closing mechanism2.
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AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Introduction
The core advantages of these brackets are more certain full arch wire
engagement, low friction between the bracket and the arch wire, less chairside
assistance needed and faster arch wire removal and insertion. All these add potential
clinical benefit in favour of these self-ligating brackets.
More often than not, most of the metal brackets are made by a metal
injection moulding process rather than milling4. Self-ligating brackets are characterized
by having greater volume, in general, than conventional brackets and by displaying
more irregular yet fine morphology due to the clip-connection system3.
Contemporary orthodontics (orthodontic trade companies and orthodontists
alike), take utmost care to apply materials that would be close to 100% biocompatible
with the tissues of the patients oral cavity5. Elements which constitute the orthodontic
fixed appliances (bands, braces, wires) are manufactured from metal alloys. Apart
+
from the potential additional release of Ni2 from nickel–titanium (NiTi) clips, clips also
make active and constant surface proximity possible between the wire and bracket
component, which may result in rising in vivo Ni2+ levels3. The use of various
combinations of metal alloys for prolonged durations in orthodontic patients warrants
special consideration regarding their biocompatibility8.
Although orthodontic alloys contain anti-corrosion materials, it has been
proven that the oral cavity is prone to corrosion in a dynamic environment. This
corrosion can release ions which are absorbed by mucosal cells, penetrate into the
blood and then gets concentrated in various body structures like hair, nail, saliva,
2
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Introduction
serum, oral mucosa9,21,19,57. It can also cause allergic and genetic disorders like
contact
allergies,
asthma,
hypersensitivity,
birth
defects
and
reproductive
problems9,11,12,48,52,56.
Allergic, cytotoxic, and even cancerous adverse effects of certain metal
ions, particularly nickel9 have sparked widespread concerns. When exposed to the
oral cavity, the orthodontic appliances are influenced by temperature, pH changes,
constant presence of saliva, foods, beverages, application of mechanical load,
mastication and abrasion. Hence the orthodontic appliances placed with in the oral
cavity are subjected to ageing processes that leads to metal dissolution or oxidation.
The surface of these metal accessories degrades as a result of this process resulting
in release of chemical components or ions into the oral environment10. Even harmless
amounts are enough to cause physiologic changes in the proven biomarkers. At noncytotoxic amounts, cations generated by dental alloys can cause considerable
biological changes (DNA synthesis, alkaline phosphatase activity). Traditionally,
allergic reactions are characterised by dose-independence. Low dosages which do
not cause inflammation due to toxicity but would cause inflammation due to irritation.
As a result, understanding the elemental release from these compounds into the oral
cavity is critical for quantification.13
Saliva, blood, epithelial cells, oral mucosa cells, urine and hair have all been
used in research on metal ion release in vitro and in vivo. The content of the
components in distinct matrices reflects different detection windows: for urine and
saliva (36–72 h, the measure of acute exposure), which is similar to blood. It is difficult
3
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Introduction
to complete the monitoring study requirements because patients experience pain
while blood and epithelial cells are being sampled. The drawback of saliva is its flow,
which is influenced by a variety of factors. Because saliva flow does not have the same
effect on all compound concentrations, it can nevertheless be a valuable matrix for
non-flow-dependent substances. To the best of our knowledge, the release of metals
in oral mucosa cells after extended interaction with fixed appliances has received little
attention despite the fact that this matrix offers the same benefits as saliva samples.
Element levels in hair represent long-term (chronic) exposure and the amount of
elements excreted this way can be used as an indirect indicator of exposure. The
concept of employing hair was born out of the large detection window. The element
analysis in nail is also found to be reliable based on the literature and also similar to
hair biomarker it is present with an added advantage with respect to the ease of
collection of the sample14.
Human hair, nails and oral mucosa are analysed with the same analytical
technique as biological samples for biomonitoring body burden of elements and
occupational exposure to metal pollution. The collected material is digested and then
subjected to multi-element analysis using a variety of spectroscopic techniques (e.g.,
ICP–OES (inductively coupled plasma–optical emission spectroscopy), ICP–MS
(inductively coupled plasma–mass spectrometry), and AAS (atomic absorption
spectroscopy) (atomic absorption spectroscopy). The instruments sensitivity allows
them to detect components even at trace quantities13,14.
4
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
AIMS AND OBJECTIVES
Aims and objectives
AIMS AND OBJECTIVES
AIM OF THE STUDY
To compare and evaluate the concentrations of nickel and chromium
ions released due to the corrosion of the intra oral metallic
components used in the fixed mechanotherapy in different
biomarkers like hair, nail and oral mucosa.
OBJECTIVE OF THE STUDY:
1. To evaluate and compare the concentrations of nickel and
chromium ions released by the conventional metal brackets and
metal self - ligating brackets in hair biomarker.
2. To evaluate and compare the concentrations of nickel and
chromium ions released by the conventional metal brackets and
metal self - ligating brackets in nail biomarker.
3. To evaluate and compare the concentrations of nickel and
chromium ions released by the conventional metal brackets and
metal self - ligating brackets in oral mucosa biomarker.
5
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
REVIEW OF
LITERATURE
Review of literature
REVIEW OF LITERATURE
Nils R. Gjerdet and Hakon Hero (1987)15 studied the release of metals like
iron(Fe), cobalt(Co) and nickel(Ni)
from cobalt-chromium and stainless steel
orthodontic arch wires as a consequence of short-term heating to different
temperatures. Wires were subjected to a 1-min heat treatment at different
temperatures and were then immersed in artificial saliva for 1 week. The
concentration
of
metals
was
determined
using
atomic
absorption
spectrophotometer with an electro thermal atomization unit. It was concluded that
the metal release from the stainless steel wire increased rapidly when subjected to
400°C or higher and for the cobalt chromium wires there was an increase at about
500°C. At temperatures above 500°C, the release of metals was 15 to 60 times
higher than the lowest values.
Margret
Rosa
Grimsdottir,
Nils
R.
Gjerdet
and
Arne
Hensten
Pettersen(1992)16 analysed the nickel (Ni) and chromium (Cr) content in different
types of metal appliances/devices used in orthodontics and the concentration of
nickel(Ni) and chromium(Cr) which was released when stored in physiologic saline.
Four face-bows, five molar bands, five brackets, and five arch wires were analysed
using scanning electron microscope and the amount of nickel and chromium
released
was
analysed
in
duplicate
with
flameless
atomic
absorption
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AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
spectrophotometry. After 14 days immersion in 0.9% sodium chloride (NaCI) it was
concluded that the largest amount of nickel (Ni) and chromium (Cr) ions were
leached out from the facebows and the least amount from the arch wires. Soldered
stainless steel face-bows were very susceptible to corrosion. The release of nickel
is related to both the composition and the method of manufacture of the appliances,
but the release was not proportional to the nickel content.
Heidi Kerosuo, Grete Moe, Erik Kleven(1995)17 determined the release of nickel
and chromium from different types of simulated orthodontic appliances especially
from a fixed appliance in a simulated oral environment under both static and
dynamic conditions. The simulated orthodontic appliances used were fixed
appliance, headgear and quad helix. The appliances were immersed in 0.9%
sodium chloride (NaCl) for three periods: 2hours, 24 hours and 7 days, post which
the solution was analysed for nickel(Ni) and chromium(Cr) concentration using
electro thermal atomic absorption spectrophotometry. It was concluded that the
total amount of chromium (Cr) released from the fixed appliance, quad helix and
headgear was significantly lower than that of nickel (Ni).
Ilken Kocadereli, Atilla Atac, Selin Kale, Durisehvar Ozer(2000)18 attempted to
determine the alterations in the chromium and nickel concentrations in the saliva
of 45 orthodontic patients treated with fixed orthodontic appliances. The first group
consisted of 15 patients (7 female, 8 male) with fixed appliances placed in their
upper and lower arches. The second group consisted of 15 patients (8 female, 7
7
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
male) with a fixed appliance placed only in the upper arch. The control group
consisted of 15 patients (7 female, 8 male) who were not undergoing orthodontic
treatment. Four samples of stimulated saliva were collected from each patient
before insertion of the fixed appliance, 1 week after insertion of the appliance, 1
month after insertion of the appliance, and 2 months after insertion of the appliance
and the samples were analysed using electrothermal atomic absorption
spectrophotometer. It was concluded that fixed orthodontic appliances do not
significantly affect nickel and chromium concentrations of saliva during the first 2
months of treatment.
Chung Ju Hwang, Ji-Soo Shin, Jung-Yul Cha (2001)19 measured the
concentration of metals like chromium (Cr), nickel (Ni), iron (Fe), copper (Cu) and
titanium (Ti) released from 320 simulated orthodontic appliances in artificial saliva
for a period of 3 months. The simulated fixed orthodontic appliances were soaked
in artificial saliva for different time periods: 1 day, 3 days, 7 days, 2 weeks, 3 weeks,
4 weeks, 8 weeks, and 12 weeks and the concentration of metals was determined
using inductively coupled plasma-mass spectrometry (ICP-MS). It was concluded
that there was a decrease in the concentration of metal released as the immersion
time increased. Also, the daily amount of chromium and nickel released was
insignificant when compared with the daily dietary intake of these metals.
8
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
Theodore Eliades, Athanasios E. Athanasiou (2002)20 discussed the
fundamentals of metallurgy and corrosion resistance for stainless steel and NiTi
alloys ,the corrosion process in Ni-containing orthodontic alloys in vitro and
intraorally and reviewed the composition and fate of leaching products. It also
summarizes the biologic effects of Ni and Ni induced hypersensitivity in orthodontic
patients. The article summarizes that the corrosive products may be adsorbed by
enamel or a portion of the corrosive product mass may be moved to the
gastrointestinal track during normal swallowing. Also, the nickel released from the
orthodontic appliances poses a risk of promoting inflammatory response in soft
tissues and induces DNA damage. The clinical manifestations of Ni hypersensitivity
are easy to diagnose, and extra oral or intraoral appliances containing nickel (Ni)
must be removed after the development of dermal or mucosal signs in the form of
rashes or swelling. Administration of cortisone-based substances to counteract
hypersensitivity has been shown to affect the tooth movement process, reducing
the movement rate, and this administration should be avoided if the symptoms are
not severe.
Pauline Garhammer, G. Schmalz, K.A. Hiller, T. Reitinger (2002)21 examined
the metal content of oral tissues in 28 patients showing persistent signs of
inflammation or other discoloration adjacent to dental cast alloys and of healthy
control sites in the same individual. Also, the composition of the cast alloys
adjacent to these affected sites was analysed and compared to alloy components
9
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
in the affected sites using atomic absorption spectroscopy. It was concluded that
metal components from almost all dental cast alloys can be detected in adjacent
tissue. High-gold and chromium cobalt (Cr-Co) alloys showed better corrosion
resistance than gold reduced and palladium (Pd) based alloys.
Gottfried Schmalz and Pauline Garhammer (2002)22 described the interactions
of dental cast alloys with living tissues such as bacterial adhesion promotion, toxic
and sub toxic effects and allergy
and related them to clinically adverse local
reactions of the oral tissues due to the metal present. It was concluded that
corrosion takes place for every dental cast alloy. There is a tendency of titanium
and high noble alloys, Palladium-silver alloys, and Cobalt-chromium alloys to be
more resistant than other alloys. It was also concluded that the prime local target
tissues for dental cast alloys are the soft tissues in mouth. Copper and silver were
the metal elements which induced cytotoxic effects of the respective alloys. Nickel,
gold, palladium and cobalt have high allergic potential compared to the other
metals.
Ralph Daniel, B. Piraccini, Antonella Tosti (2004)23 reported examples of heavy
metal poisoning, which was diagnosed because of the hair or nail symptoms and
reviewed drugs and toxins that can be detected in hair and nails. They discussed
the application of hair/nail analysis in general and in forensic medicine. It was
concluded that the advantages of analyzing hair and nail samples include their
easy and non-invasive collection, the small sample size required for analysis, and
10
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
their easy storage at room temperature. The nails are an interesting substrate due
to their slow growth rate making them useful for retrospective analysis. Levels of
nickel in the nails reflect occupational exposure to metal.
Ronny Fors and Maurits Persson (2006)24 compared the content of nickel in the
saliva and dental biofilm in 24 young patients with and without orthodontic
appliances and determined the possible influence of dietary intake of nickel on
recorded nickel levels. In order to reveal recent extremes of nickel exposure from
diet or smoking, the participants were asked to answer a questionnaire on food
intake and smoking during the previous 48 hours. The nickel (Ni) content was
determined using electrothermal atomic absorption spectrometry (ETAAS). It was
concluded that a significantly higher content of nickel was found in the plaque and
saliva of patients with orthodontic appliances compared with non-orthodontic
patients. Moreover, in orthodontic patients, a significantly higher nickel content was
found in plaque from metal surfaces (band and brackets) than from enamel
surfaces. Also, the outcomes of differences in salivary nickel between the groups
were not explained by differences in dietary intake.
Hassan I Afridi, Tasneem G Kazi, Mohammad K Jamali, Gul H Kazi,
Mohammad B Arain, Nusrat Jalbani, Ghulam Q Shar and Raja A Sarfaraz
(2006)25 determined the concentration of cadmium (Cd), chromium (Cr), lead (Pb)
and nickel (Ni) in the biological samples like scalp hair, blood and urine of longterm exposed 90 steel production workers to evaluate the degree of their exposure.
11
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
The metal concentration was determined using graphite furnace atomic absorption
spectrophotometry. It was concluded that the level of lead (Pb), cadmium (Cd) and
nickel (Ni) in scalp hair, blood and urine samples were significantly higher in
workers than those of the controls.
Sukumar, R. Subramanian (2006)26 determined the levels of of cadmium (Cd),
chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair and
finger nails of 72 males and 82 females from New Delhi. Scalp hair and fingernails
were sampled along with a questionnaire from urban and rural subjects of New
Delhi and patients of hypertension, coronary heart disease, and diabetes were
identified clinically. Cadmium, chromium, copper, nickel, lead and zinc
concentrations were determined by atomic absorption spectrophotometry. It was
concluded that the higher levels of chromium (Cr), copper (Cu) and nickel (Ni) and
lower level of zinc (Zn) were observed in the hair of urban subjects, when compared
to that of villagers. Except chromium (Cr), the other metal levels were higher in
nails than in hair.
F Amini, A Borzabadi Farahani, A Jafari, M Rabbani (2008)27 compared the
concentrations of Nickel (Ni), Chromium (Cr) and Cobalt (Co) in oral mucosa cells
of 10 male and 20 female patients with and without fixed orthodontic appliances
using spectrophotometric analysis and concluded that no significant differences
were found in chromium and cobalt content but the nickel content in mucosa
samples was found to be significantly higher.
12
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
Rodrigo Matos de Souzaa, Luciane Macedo de Menezesb (2008)28 assessed
the in vivo release of nickel, chromium, and iron ions into saliva by different metallic
brackets using atomic absorption thermal electric spectrophotometer and it was
concluded that Nickel and chromium ion concentrations increased immediately
after placement of the appliance in the mouth and there was no alteration in iron
levels after placement of the appliance.
Kuhta M, Pavlin D, Slaj M, Varga S, Slaj M, Lapter-Varga M(2009)29 examined
the effects of three different parameters—pH value, type of archwire, and length of
immersion—on release of metal ions from orthodontic appliances and observed
the release of six different metal ions was observed: titanium (Ti), chromium (Cr),
nickel (Ni), iron (Fe), copper (Cu), and zinc (Zn) using high-resolution inductively
coupled plasma mass spectrometry. It was concluded that release of metal ions
was influenced by composition of the orthodontic archwire, but this was not
proportional to the content of metal in the wire and the levels of released ions were
sufficient to cause delayed allergic reactions.
Evangelia Petoumenou et al (2009)30 attempted to examine whether nickeltitanium (Ni-Ti) archwires cause an increase of nickel concentration in the saliva of
18 orthodontic patients to estimate the possible risk of these archwires in patients
who have nickel hypersensitivity. Saliva samples were collected before orthodontic
13
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
treatment, after placement of the bands and brackets, 2 weeks later and before
placing the Ni-Ti archwires, immediately after placing the Ni-Ti archwires, 4 weeks
after placing the wires, and 8 weeks after placing the wires and were analysed
using mass spectrometry. It was concluded that nickel leaching occurred after
placement of the bands and brackets and after placement of the Ni-Ti archwires,
associated with an increase of the nickel ion concentration in the patient’s saliva.
However, this effect decreased within 10 weeks.
Madhumitha Natarajan, Sridevi Padmanabhan, Arun Chitharanjan and
Malathi Narasimhan (2011)31 evaluated the genotoxic damage in the oral mucosal
cells of patients wearing fixed appliance; the persistence of these genotoxic
changes at 1 month after debonding the appliance and the nickel and chromium
ion contents in these cells. 40 oral mucosa cell samples were collected and
analysed using inductively coupled plasma-mass spectrometry. It was concluded
that the oral mucosal cells showed genotoxic damage in healthy patients
undergoing orthodontic treatment but these genotoxic changes decreased
significantly in a month’s time after removal of the fixed appliance. Also the nickel
and chromium ion concentrations in the oral mucosal cells were not significantly
different between the groups. There was no correlation between the nickel and
chromium ion concentrations and the genotoxic changes observed.
Hend Salah Hafez, Essam Mohamed, Faten Hussein, Wael Attia Tawfik, Emad
A. Al-Ashkar and Yehya Ahmed Mostafae (2011)32 evaluated four combinations
14
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
of brackets and archwires for Cytotoxicity, genotoxicity, and Nickel and Chromium
release using buccal mucosa cell samples. Cellular viability was evaluated using
the trypan blue exclusion dye test and the cellular nickel and chromium contents
were measured by using graphite furnace-atomic absorption spectrometry. It was
concluded that, buccal mucosa cells of patients treated with fixed orthodontic
appliances for 6 months showed significant increases in nickel and chromium
content, with significant decreases in viability and damage to the DNA and
stainless steel brackets with stainless steel archwires showed the least biologic
damage, whereas the titanium brackets with nickel-titanium archwires produced
the greatest cytotoxicity and genotoxicity. Nickel and chromium concentrations
were also increased at 3 months and 6 months interval.
Mikulewicz M, Chojnacka K, Zelinska A, Michalak I (2011)33 investigated the
exposure of patients to metals released from orthodontic appliances using hair
sampled from a group of patients. The concentration of Nickel (Ni), Chromium (Cr),
Manganese (Mn), and Iron (Fe) was determined using inductively coupled plasma
spectroscopy. It was concluded that 22% of patients undergoing orthodontic
treatment had elevated levels of Nickel in hair and showed increased levels of
Chromium and Iron as well.
Marcin Mikulewicz, Katarzyna Chojnacka, Barbara Wozniak, Patrycja
Downarowicz (2012)34 conducted an in vitro study to investigate whether the use
of stainless steel orthodontic appliances can be considered a potentially significant
15
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
source of exposure to toxic metals by evaluating the chemical composition of
brackets, bands and wires using scanning electron microscope (SEM) and
concluded that highest correlations were between Fe and Cr and between Ni and
Cr suggesting that these ions were released together as a result of corrosion.
Among the toxic elements determined, nickel level increased the most.
Fariborz Amini, Alireza Jafari, Parviz Amini and Sepehr Sepasi (2012)35 tested
the hypothesis that there is no difference in salivary metal ion content between
subjects with fixed orthodontic appliances and their same-gender sister or brother
without any orthodontic appliance. Determination of the metal content in the saliva
samples
of
28
subjects
was
analysed
using
an
atomic
absorption
spectrophotometer. It was concluded that fixed orthodontic appliance therapy for
an average period of 16 months lead to increased levels of Ni and Cr ions in the
saliva of patients. The low levels of these metal ions are of concern to patients with
allergies and they do not lead to problems in the majority of orthodontic patients as
toxic levels are never attained.
Mostafa Abtahi, Arezoo Jahanbin, Masoud Yaghoubi, Habibollah Esmaily,
Hanieh Zare (2013)9 evaluated the release of nickel ions into the hair strands of
24 female patients undergoing fixed orthodontic therapy compared with the control
group in a 4-month duration. Analysis of nickel concentration in hair was performed
using atomic absorption spectrometer and it was concluded that that there was
16
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
significant increase in hair nickel concentration of baseline and after four months
for cases and controls but in case group this increase was more rapid.
Raul Magnoler Sampaio Mei, Antonio Adilson Soares de Lima, Jorge Cesar
Borges Leao Filho, Orlando Motohiro Tanaka, Odilon Guariza Filho, Elisa
Souza Camargo (2013)36 evaluated the cytometry and cytomorphology of oral
mucosa epithelial cells adjacent to orthodontic accessories using liquid-based
exfoliative cytology. 20 samples were collected at three intervals: before installing
the accessories; 30 days after installing the accessories and 30 days after their
removal. It was concluded that metal brackets, stainless steel wires and metal and
elastic ties can induce cytomorphometric and cytomorphological changes to
adjacent oral mucosa cells which suggests an adaptive response to the physical
stimulus. The mucosa’s adaptive response to the injury caused by these
accessories is reversible and the benefits of the orthodontic treatment outweigh
the disadvantages of discomfort and possible lesion of the oral mucosa.
Mervat A. Al-Awadeen, Ahmad S Al-Hiyasat, Adnan M. Massadeh and Yousef
S. Khader (2014)37 attempted to determine the heavy metal concentrations
including Cobalt (Co), Chromium (Cr) Nickel (Ni) in scalp hair and fingernail
samples of 55 dental technicians using spectrophotometric analysis and concluded
that nickel was found to have the highest concentration in hair and fingernails.
17
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
Fariborz Amini, Mobina Mollaei, Saghar Harandi and Vahid Rakhshan (2014)38
evaluated hair nickel and chromium levels in 12 male and 12 female patients
undergoing fixed orthodontic therapy.
Scalp hair nickel (Ni), Chromium (Cr)
concentrations were determined in both males and females, at two time points:
baseline (immediately before treatment) and 6 months later using atomic
absorption spectrometry. It was concluded that after 6 months the nickel
concentration increased by 387% and the chromium concentration increased by
16% and the difference between the increase of nickel in men versus the increase
in women was not significant.
Marcin Mikulewicz, Paulina Wołowiec, Bartłomiej Loster, Katarzyna
Chojnacka (2015)14 evaluated the metal ions released to human hair in patients
undergoing orthodontic treatment with fixed appliances using ICP-OES(inductively
coupled plasma – optical emission spectroscopy) and concluded that there is an
increased content of Chromium(Cr), Nickel(Ni), and Iron(Fe) in hair as a result of
orthodontic treatment and
the content of Chromium(Cr) was statistically
significantly higher during the treatment than before the beginning of therapy.
Rabindra S Nayak, Bharti Khanna, Azam Pasha, K Vinay, Anjali Narayan , K
Chaitra (2015)8 evaluated the release of nickel and chromium ions in saliva from
orthodontic appliances in the oral cavity using Inductively Coupled Plasma-Mass
Spectrometer (ICP-MS). 30 samples were collected prior to commencement of
treatment, after initial aligning wires and after 10-12 months of treatment. It was
18
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
concluded that there was a statistically significant increase in the nickel and
chromium ion concentration after the initial aligning phase with an increase of 10.35
ppb in nickel ion concentration and an increase of 33.53 ppb in chromium ion
concentration. A statistically significant increase of 17.92 ppb was found in salivary
chromium ion concentration at the end of 10-12 months.
Arash Azizi, Abdolreza Jamilian, Francesca Nucci, Zinat Kamali, Nima
Hosseinikhoo and Letizia Perillo (2016)39 compared the effects of different
immersion times of 40 round and rectangular NiTi wires and on the release of
Nickel (Ni) and Titanium (Ti) ions in artificial saliva to determine the amount of
Nickel (Ni) and Titanium (Ti) ions released after each immersion period using
inductively coupled plasma atomic emission spectrometry (ICP-AES). It was
concluded that the amount of nickel and titanium released from rectangular wires
was significantly higher than the ions released from round wires in all immersion
periods and the accumulated amount of metal ions increased with immersion
period while the average ions released per day decreased with immersion period.
Mashallah Khaneh Masjedi, Ozra Niknam, Nima Haghighat Jahromi, Pedram
Javidi, Vahid Rakhshan (2016)40 attempted to measure salivary nickel in fixed
orthodontic patients before treatment and 2 months after beginning of fixed
treatment using metal injection moulded brackets and three different NiTi archwires
– Niti (nickel titanium), Cu NiTi (copper nickel titanium) and epoxy nickel titanium
using atomic absorption spectrophotometry and concluded that salivary nickel
19
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
release increases in patients with metal injection moulded brackets and NiTi wires
and the lowest rate of time-dependent increase was observed with the epoxycoated NiTi group, followed by copper NiTi archwires and the conventional NiTi
wires.
V. Causado-Vitola, M Rumbo-Zubiría, L. Fang and A. Díaz Caballero (2016)41
determined the levels of nickel in the oral cavity through samples of saliva, biofilm
and the oral mucosa in 30 subjects, before and during 6 months of the orthodontic
treatment using atomic absorption spectrometer with graphite furnace. It was
concluded that nickel levels in the oral cavity vary after the placement of the
orthodontic appliances, these changes being more significant in the saliva and
biofilm samples.
Mashallah Khaneh
Elham Hormozi
Masjedi,
and
Nima Haghighat
Vahid Rakhshanet
Jahromi,
(2017)11
Ozra Niknam,
evaluated
the
hair
concentrations of nickel and chromium in 24 female and 22 male orthodontic
patients before treatment and 6 months after beginning fixed mechanotherapy
using spectrophotometric analysis between conventional (two-piece) brackets and
MIM brackets and concluded that there was significant increase in nickel and
chromium content in both the groups, bracket types, age and gender had no
significant influence on ion concentrations.
20
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
Patrycja Downarowicz and Marcin Mikulewicz (2017)5 discussed the release of
metal ions from fixed orthodontic appliances and the influence of the concentration
of metal ions in the cells of oral mucosa of orthodontic patients and their influence
on DNA damage in in-vivo tests. The concentrations of metal ions – nickel (Ni),
chromium (Cr), cobalt (Co), iron (Fe) and molybdenum (Mo) were determined using
inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption
spectrometry (AAS) with graphite furnace. Statistically significant differences were
found in concentration of nickel (Ni) ions, cobalt (Co) ions and chromium (Cr) ions
but the presence of metal ions released from orthodontic appliances did not induce
DNA damage and did not reduce the cellular viability of mucosa cells. It was
concluded that titanium (Ti) is the most biocompatible material and stainless steel
was the least biocompatible material used in the production of fixed orthodontic
appliances.
Vinny Bhasin, Swati J Pustake, Viprat Joshi, Anil Tiwari, Meenakshi Bhasin,
Ramandeep S Punia(2017)7 assessed and evaluated the changes occurring in
nickel (Ni) and chromium (Cr) levels in the GCF during fixed orthodontic treatment
using atomic absorption spectrophotometry. GCF collection was done in 30
subjects at three different time intervals – baseline, 1st month and 6th month. It was
concluded that intensification of nickel (Ni) and chromium (Cr) levels might occur
in the GCF after 1st and 6th months of fixed orthodontic treatment.
21
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Review of literature
Jamshidia S, Kamelb M, Mirzaieb M, Sarrafana A, Khafric S and Parsian H
(2017)12 measured the Nickel and Chromium ion levels in the scalp hair of patients
treated with fixed orthodontic appliances for a period of 1 year. Analysis of the Cr
and Ni was performed using atomic absorption spectrophotometer by graphite
furnace method. It was concluded that the Nickel and Chromium levels significantly
increased in people treated with fixed orthodontic appliances for one year, and
Nickel content was greater .There was no significant association between the
patient’s age and the ion concentrations.
Piotr Buczko, Dariusz Pawlak, Irena Kasacka (2018)42 aimed to investigate the
concentration of nickel, 3-hydroxykynurenine, total oxidative status in saliva and
caspase-3 in epithelial cells in 10 subjects before and one week after orthodontic
treatment using atomic absorption spectrometer. Saliva and epithelial cells were
collected between 8 a.m. and 9 a.m. on two occasions, immediately before the
insertion of the appliances, and one week after treatment. It was concluded that a
significantly higher concentration of nickel and 3-hydroxykynurenine in the saliva
of subjects one week after appliance insertion. These changes were accompanied
by enhanced total oxidative status and a greater number of caspase-3 immuno
reactive cells.
22
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
MATERIALS AND
METHODS
Materials and methods
MATERIALS AND METHODOLOGY
SUBJECTS AND ELIGIBILITY CRITERIA:
The samples are collected from the patients reporting to the Department of
Orthodontics and Dentofacial Orthopaedics, at Panineeya Mahavidyalaya Institute of
Dental Sciences, Hyderabad for fixed orthodontic treatment. The study was conducted
after obtaining ethical clearance from the institution and an informed consent from the
patients.
A total of 30 patients were included in the study.
30 patients
15 patients
15 patients
Fixed orthodontic
treatment with
conventional metal
brackets
Fixed orthodontic
treatment with
self - ligating metal
brackets
Fig 1: Flow chart of sample distribution
23
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Samples collected:
I.
Hair sample
II.
Nail sample
III.
Oral mucosal cell sample
Inclusion Criteria:
•
Patients indicated with fixed appliance therapy requiring four premolar
extractions with mild to moderate crowding.
Exclusion Criteria:
•
History of previous orthodontic therapy of any kind.
•
Presence of any systemic diseases,
•
History of allergic reactions
•
Medication intake during the course of study
•
Smoking or alcohol consumption
•
Presence of any metal restorations (e.g., amalgam fillings or fixed
prostheses) before or during the treatment
•
Presence of any hair color or hairdressing
•
Patients with single missing tooth or multiple missing teeth
•
Patients requiring interception of habits like tongue crib etc
•
Patients using Nail Paints.
•
Patients with Tongue / Lip Piercings
24
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Orthodontic appliances:
Orthodontic appliances used were:
1) conventional metal brackets obtained from Ormco, Glendora, California and
were made of SS
Fig 2: Ormco conventional metal Brackets (MBT prescription - 0.22” slot)
2) DamonTM Q self-ligating metal brackets obtained from Ormco, Glendora,
California and were made of SS
Fig 3: Damon™ Q self - ligating metal Brackets
(Damon prescription - 0.22” slot)
25
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Methodology:
The hair, nails and oral mucosa cell samples were collected and sent to the laboratory
for Nickel and chromium using the Atomic Absorption Spectrometer. The abovementioned samples would be collected in two intervals.
a. T0 – Before starting fixed orthodontic treatment
b. T1 – 6 months after commencing fixed orthodontic treatment
Sample Collection:
Hair sampling:
The samples were collected twice, initially before commencing the treatment
(T0) and the next time after 6 months (T1). During the sample collection, 5–6 cm of
hair was cut from the occipital region of the head in the neck proximity, using a SS
surgical blade. The final sample was weighed upto 1 gm. The hair samples were
kept in paper envelopes.
Fig 4: Storage of hair samples
26
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Nail sampling:
The samples were collected twice, initially before commencing the treatment
(T0) and the next time after 6 months (T1). During the sample collection, the nails
from the left hand were cut using a nail cutter and the final sample was weighed
upto 1 gm. The nail samples were kept in paper envelopes.
Fig 5: Storage of nail samples
Oral mucosal cells sampling:
The samples were collected twice, initially before commencing the treatment
(T0) and the next time after 6 months (T1). The oral mucosal cells were collected
from each subject by gentle scraping of the inside part of the right and left buccal
mucosa with an interdental brush in a sweeping motion, after rinsing the mouth
several times with water, to remove exfoliated dead cells. The interdental brush
was then stirred in a polypropylene tube containing 5ml of Phosphate buffered
saline solution.
27
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Fig: 6 interdental brushes for the collection of oral mucosa samples
Fig 7: Phosphate buffered saline solution for storage of oral mucosa cells
Fig 8: Polypropylene tubes for storage of oral mucosa cells
28
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Fig 9: Storage of samples
Sample Preparation:
Preparation of Hair sample:
Hair samples were collected and cut into very small pieces with stainless steel
scissors and soaked in a mixture solution with a ratio of 3: 1: 20 (v/v) of diethyl
ether, acetone and deionized water for 1 h with use of ultrasonic bath and then
rinsed thoroughly with deionized water. The hair samples were placed in glass
petri-dishes and then dried at 105ºC for 24 h in an oven.
This was followed by
1. A weight of 1 g hair samples were placed in a porcelain evaporating
dish.
2. The hair samples were digested with a mixture of HNO3 and H2O2
with a ratio of 6:2 (v/v) in the porcelain evaporating dish.
3. The digested samples were then heated on a hot plate at 80ºC to
near dryness.
29
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
4. An aliquot 10 ml of 0.1M HNO3 was added to each digested sample.
5. The extract was filtered via Whatman filter paper No. 42 and was kept
in a 10 ml polyethylene flask until analysis.
Preparation of Nail sample:
Nail samples were collected and cut into very small pieces with stainless steel
scissors and soaked in a mixture solution with a ratio of 3: 2: 5 (v/v) of diethyl ether,
acetone and deionized water for 1 h with use of ultrasonic bath and then rinsed
thoroughly with deionized water. The nail samples were placed in glass petridishes, and then dried at 105ºC for 24 h in an oven.
This was followed by
1. A weight of 1 g hair samples were placed in a porcelain evaporating
dish.
2. The hair samples were digested with a mixture of HNO3 and H2O2
with a ratio of 3:1 (v/v) in the porcelain evaporating dish.
3. The digested samples were then heated on a hot plate at 80ºC to
near dryness.
4. An aliquot 10 ml of 0.1M HNO3 was added to each digested sample.
5. The extract was filtered via Whatman filter paper No. 42 and was kept
in a 10 ml polyethylene flask until analysis.
30
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Preparation of Oral mucosa cell sample:
5 mL of the oral mucosa cell sample was treated with 1 drop of pure nitric acid
(68%) and heated in a water bath for about half an hour at 80 °C. The sample was
cooled at room temperature, and the final volume was measured for the estimation
of nickel and chromium levels. 2 mL of the sample volume was required for the
analysis.
Measurement and instrumentation:
The samples were analyzed using graphite furnace atomic absorption
spectrometry (AA700, Analytik Jena, Germany), with detection limits of 1 ppb for
nickel and 0.5 ppb for chromium.
Fig 10: Graphite furnace atomic absorption spectrometer
31
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Materials and methods
Element
Chromium
Nickel
Wavelength
232 nm
357nm
Band pass
0.7nm
0.7nm
Lamp Type
HCl
HCl
Lamp Current
25mA
25mA
Purge Gas
Argon
Argon
Table 1: various levels at which the nickel and chromium ions are detected
32
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
RESULTS
Results
RESULTS
This study was conducted to evaluate and compare the release of nickel
and chromium ions from conventional metal brackets and metal self - ligating brackets
in nails, hair and oral mucosa cells before starting the orthodontic treatment and 6
months after initiating the fixed appliance therapy.
A total of 30 patients who required orthodontic treatment with fixed
orthodontic appliances were selected for the study. They are divided into 2 groups,
Group A – received fixed orthodontic treatment with conventional metal brackets and
Group B – received fixed orthodontic treatment with metal self - ligating brackets. The
samples were collected at T0 – Before placement of any fixed orthodontic appliance
and at T1 – Six months after placement of fixed orthodontic brackets. The amount of
nickel and chromium concentration at T0 and T1 was measured using Graphite furnace
atomic absorption spectrometer.
Data was analysed using SPSS version 23. Descriptive, Paired t test for before
and after comparison, Independent t test for inter gender comparison, Pearson
correlation test for comparison of age with various parameters.
Formulation of Hypothesis:
Null Hypothesis H0 = There is no difference in Before and After treatment nickel and
chromium values in various tissues.
33
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Alternate Hypothesis Ha = There is difference in Before and After treatment nickel
and chromium values in various tissues.
P value < 0.05 is considered as statistically significant.
If P value < 0.05 we can reject the null hypothesis and consider the alternate
hypothesis
If P value > 0.05 we retain the null hypothesis
TABLE 2 – COMPARISON OF NICKEL CONCENTRATION IN NAIL SAMPLES
BEFORE AND AFTER THE TREATMENT IN GROUP A
Location
Duration
Mean
N
Std.
Deviation
Std.
Error
Mean
Before
2.75
15
1.45
0.37
Nail
After
5.11
15
2.12
Mean
Difference
P value
-2.35979
<0.001**
0.55
Inference: A paired samples T test was computed to analyse the nickel concentration
before and after the fixed appliance therapy in Group A. The analysis revealed that
there is statistically significant increase in the nickel values in the nail samples after
treatment with conventional metal brackets.
34
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
TABLE 3 – COMPARISON OF NICKEL CONCENTRATION IN NAIL SAMPLES
BEFORE AND AFTER THE TREATMENT IN GROUP B
Location
Duration
Mean
N
Std.
Deviation
Std.
Error
Mean
Before
3.95
15
1.204
.311
Nail
After
4.99
15
1.337
Mean
Difference
P value
-1.03973
<0.001**
.345
Inference: A paired samples T test was computed to analyse the nickel concentration
before and after the fixed appliance therapy in Group B. The analysis revealed that
there is statistically significant increase in the nickel values in the hair sample after
treatment with self-ligating metal brackets.
TABLE 4 – COMPARISON OF CHROMIUM CONCENTRATION IN NAIL
SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP A
Location Duration Mean
N
Std.
Std.
Deviation Error
Mean
2.75
15
0.72
Before
Mean
P value
Difference
0.19
Nail
-2.57019
After
5.32
15
1.79
<0.001**
0.46
35
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Inference: A paired samples T test was computed to analyse the chromium
concentration before and after the fixed appliance therapy in Group A. The analysis
revealed that there is statistically significant increase in the chromium values in the
nail sample after treatment with conventional metal brackets.
TABLE 5 – COMPARISON OF CHROMIUM CONCENTRATION IN NAIL
SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP B
Location
Duration
Mean
Nail
Before
9.30
After
10.63
N
Std.
Deviation
Std.
Error
Mean
Mean
Difference
P value
15
1.023
.264
-1.32800
<0.001**
15
1.122
.290
Inference: A paired samples T test was computed to analyse the chromium
concentration before and after the fixed appliance therapy in Group B. The analysis
revealed that there is statistically significant increase in the chromium values in the
nail sample after treatment with self-ligating metal brackets.
36
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
TABLE 6 – COMPARISON OF NICKEL CONCENTRATION IN HAIR SAMPLES
BEFORE AND AFTER THE TREATMENT IN GROUP A
Location Duration Mean
N
Std.
Std.
Deviation Error
Mean
Before
15
1.42
3.10
Mean
P value
Difference
0.37
-2.63973
<0.001**
Hair
After
5.74
15
2.31
0.60
Inference: A paired samples T test was computed to analyse the nickel concentration
before and after the fixed appliance therapy in Group A. The analysis revealed that
there is statistically significant increase in the nickel values in the hair sample after
treatment with conventional metal brackets.
TABLE 7 – COMPARISON OF NICKEL CONCENTRATION IN HAIR SAMPLES
BEFORE AND AFTER THE TREATMENT IN GROUP B
Location Duration Mean
N
Std.
Std.
Deviation Error
Mean
Mean
P value
Difference
Hair
-2.38120
Before
9.28
15
.555
.143
After
11.67
15
1.042
.269
<0.001**
37
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Inference: A paired samples T test was computed to analyse the nickel concentration
before and after the fixed appliance therapy in Group B. The analysis revealed that
there is statistically significant increase in the nickel values in the hair sample after
treatment with self-ligating metal brackets.
TABLE 8 – COMPARISON OF CHROMIUM CONCENTRATION IN HAIR
SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP A
Location
Hair
Duration
Mean
N
Std.
Deviation
Std.
Error
Mean
Before
1.51
15
0.75
0.19
After
2.94
15
0.83
0.22
Mean
Difference
P value
-1.43125
<0.001**
Inference: A paired samples T test was computed to analyse the chromium
concentration before and after the fixed appliance therapy in Group A. The analysis
revealed that there is statistically significant increase in the chromium values in the
hair sample after treatment with conventional metal brackets.
38
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
TABLE 9 – COMPARISON OF CHROMIUM CONCENTRATION IN HAIR
SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP B
Location Duration Mean
N
Std.
Std.
Deviation Error
Mean
Mean
P value
Difference
Hair
-1.00220
Before
3.90
15
.956
.247
After
4.90
15
.923
.238
<0.001**
Inference: A paired samples T test was computed to analyse the chromium
concentration before and after the fixed appliance therapy in Group B. The analysis
revealed that there is statistically significant increase in the chromium values in the
hair sample after treatment with self-ligating metal brackets.
TABLE 10 – COMPARISON OF NICKEL CONCENTRATION IN ORAL MUCOSA
SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP A
Location
Duration
Mucosa
Before
Mean
N
Std.
Deviation
Std.
Error
Mean
1.12
15
1.19
0.31
2.43
15
1.37
0.35
Mean
Difference
P value
-1.30829
<0.001**
After
39
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Inference: A paired samples T test was computed to analyse the nickel concentration
before and after the fixed appliance therapy in Group A. The analysis revealed that
there is statistically significant increase in the nickel values in the nail samples after
treatment with conventional metal brackets.
TABLE 11 – COMPARISON OF NICKEL CONCENTRATION IN ORAL MUCOSA
SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP B
Location Duration Mean
N
Std.
Std.
Deviation Error
Mean
P value
Difference
Mean
Mucosa
Before
3.47
15
1.600
.413
After
4.46
15
1.733
.447
-.99060
0.010*
Inference: A paired samples T test was computed to analyse the nickel concentration
before and after the fixed appliance therapy in Group B. The analysis revealed that
there is statistically significant increase in the nickel values in the hair sample after
treatment with self-ligating metal brackets.
40
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
TABLE 12 – INTER GROUP COMPARISON OF NICKEL CONCENTRATION
Parameter Group
N
Mean
Std.
Std.
Deviation Error
Mean
Mean
P
Difference value
Hair
Group A
15
2.38
1.06
0.27
-.259
0.621
NS
Group B
15
2.64
1.70
0.44
Group A
15
1.04
0.37
0.09
-1.320
0.005*
Group B
15
2.36
1.63
0.42
Group A
15
0.99
1.30
0.34
-.318
0.386
NS
Group A
15
1.31
0.52
0.13
Nail
Oral
Mucosa
Inference: There is statistically significant difference present in the deposition of nickel
in nails among the self-ligating group compared to the conventional group.
Mean
Nickle
3.00
2.50
2.00
1.50
1.00
0.50
0.00
2.38
2.64
2.36
1.04
0.99
1.31
Previous Present
Group A Previous
Group B Present
Group A Previous
Group B Present
Group A
Hair
Nail
Group B
Oral Mucosa
Graph 1: Inter Group comparison of nickel concentration
41
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
TABLE 13 – COMPARISON OF CHROMIUM CONCENTRATION IN ORAL
MUCOSA SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP A
Location
Duration
Mucosa
Before
After
Mean
N
Std.
Deviation
Std.
Error
Mean
1.12
15
1.74
0.45
2.83
15
1.61
0.41
Mean
Difference
P value
-1.71045
<0.001**
Inference: A paired samples T test was computed to analyse the chromium
concentration before and after the fixed appliance therapy in Group A. The analysis
revealed that there is statistically significant increase in the chromium values in the
oral mucosa sample after treatment with conventional metal brackets.
TABLE 14 – COMPARISON OF CHROMIUM CONCENTRATION IN ORAL
MUCOSA SAMPLES BEFORE AND AFTER THE TREATMENT IN GROUP B
Location Duration Mean
N
Std.
Std.
Deviation Error
Mean
P value
Difference
Mean
Mucosa
Before
2.02
15
1.028
.265
After
2.86
15
1.218
.315
-.84173
<0.001**
42
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Inference: A paired samples T test was computed to analyse the chromium
concentration before and after the fixed appliance therapy in Group B. The analysis
revealed that there is statistically significant increase in the chromium values in the
oral mucosa sample after treatment with self-ligating metal brackets.
TABLE 15 – INTER GROUP COMPARISON OF CHROMIUM CONCENTRATION
Parameter
Study
N
Mean
Std.
Std.
Deviation Error
Mean
Mean
Difference
P
value
Hair
Group A
15
1.00
0.31
0.08
-0.43
0.106
NS
Group B
15
1.43
0.94
0.24
Group A
15
1.33
0.40
0.10
-1.24
0.002*
Group B
15
2.57
1.38
0.36
Group A
15
0.84
0.37
0.10
-0.87
0.002*
Group B
15
1.71
0.88
0.23
Nail
Oral
Mucosa
Inference: There is statistically significant difference present in the deposition of
Chromium in nails and Oral mucosa when compared to previous study, higher values
in present study.
43
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Chromium
3.00
2.57
Mean
2.50
2.00
1.50
1.43
1.00
1.71
1.33
0.84
1.00
0.50
0.00
Previous Group
Present
Previous
Present
A Group
BA
Group
Group B Previous
Group A Present
Group B
Hair
Nail
Oral Mucosa
Graph 2: Inter Group comparison of chromium concentration
TABLE 16 - CORRELATION BETWEEN AGE AND NICKEL AND CHROMIUM
CONCENTRATION
Chromium
Nickel
Comparison
between
Age
Hair
Nail
Mucosa
Hair
Age Pearson
1
-.042
-.133
.100
-.335
Sig.
.883
.637
.723 NS .223
(2-tailed)
NS
NS
NS
30
30
Nail
Mucosa
.495
-.141
.061 NS
.616 NS
30
30
Correlation
N
30
30
30
Inference: A Pearson correlation test was computed for comparison of age with
concentration of nickel and chromium in hair, nails and oral mucosa cells in both the
44
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
groups. There is no statistically significant correlation present between age and nickel
/ chromium deposition in various body sites.
TABLE 17 : INTER GENDER COMPARISON OF NICKEL CONCENTRATION IN
VARIOUS LOCATIONS
Location Gender N
Mean
Std.
Std.
Deviation Error
Mean
Mean
P value
Difference
Hair
14
1.8140
.80405
.30390
-1.06350
Female 16
2.8775
1.03789
.36695
Male
14
.9111
.35482
.13411
Female 16
1.1523
.36172
.12789
Male
14
1.3461
.40928
.15470
Female 16
.6795
1.72845
.61110
Nail
Mucosa
Male
0.638
NS
-.24111
0.216
NS
.66664
0.339
NS
Inference: An independent t test was computed for intergender comparison. There is
no statistically significant difference present in nickel concentration at various location
in among both genders (p>0.05). It indicates that gender has no influence in Nickel
concentration.
45
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Mean
Mean concentration of Nickel
among gender
2.88
3.00
2.50
2.00
1.50
1.00
0.50
0.00
1.81
1.15
0.91
Male
Female
Hair
Male
1.35
0.68
Female
Male
Nail
Female
Mucosa
Graph 3: Mean concentration of nickel among gender
TABLE 18 : INTER GENDER COMPARISON OF CHROMIUM CONCENTRATION
IN VARIOUS LOCATIONS
Location Gender N
Mean
Std.
Std.
Deviation Error
Mean
Hair
.9649
.30738
Nail
Mucosa
Male
14
Mean
P
Difference value
.11618 -.07002
0.676
Female 16
1.0349 .32401
.11455
NS
Male
14
1.4191 .47270
.17866 .17089
0.426
Female 16
1.2483 .32827
.11606
NS
Male
14
.9026
.42155
.15933 .11407
0.572
Female 16
.7885
.34043
.12036
NS
46
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Results
Inference: An independent t test was computed for intergender comparison. There is
no statistically significant difference present in chromium concentration at various
location in among both genders (p>0.05). It indicates that gender has no influence in
Nickel concentration.
Mean concentration of chromium among gender
1.42
Mean
1.50
1.00
.96
1.03
1.25
.90
.79
.50
.00
Male Female Male Female Male Female
Hair
Nail
Mucosa
Graph 4: Mean concentration of chromium among gender
47
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND ORAL
MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
DISCUSSION
Discussion
DISCUSSION
The conventional brackets used in fixed appliance therapy has undergone several
modifications since decades. Many orthodontic companies have created their own
bracketing systems, each with its own set of prescriptions, treatment philosophies
and mechanics. However, they all had one thing in common i.e; the ligation
technique. Various forms of ligatures have been proposed with their own advantages
and disadvantages. The steel ligatures provide efficient and effective tooth
movement due to more effective engagement of the arch wire into the bracket slot
but this method of ligation increases the chair side time by 12 minutes (Harradine,
2003)63. They also necessitate careful tucking on the ends to avoid soft tissue harm,
but because of the various daily routine activities, they have a tendency to get
dislodged between sessions, thus causing irritation and ulceration (Schumacher et
al., 1990; Bender & Gruendeman, 1993). To overcome the proposed disadvantages
of steel ligatures, elastomeric ligatures had replaced the steel ligatures with a few
major disadvantages like reducing the chair side time and reducing the chances of
developing ulcerations for patients64. The brackets used in our study are Ormco
conventional metal Brackets (MBT prescription - 0.22” slot) and Damon Q selfligating Brackets (Damon prescription 0.22” slot). Similar kind of banding protocols
were followed to band the subjects in both the group to eliminate any variation in the
metal ion release as the bands account to solid metal surface area in the oral cavity
covering the tooth in all the four surfaces.
48
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
Self-ligating brackets are ligature-less bracketing system with a mechanical
component in built to seal the rectangular edgewise slot. The sliding door replaced
the steel/elastomeric ligature and secured the arch wire in the bracket slot. The
movable fourth wall of the bracket is utilised to turn the slot into a tube in self-ligating
brackets57.
Furthermore, orthodontic brackets, whether conventional or self-ligating,
have their own advantages and disadvantages in terms of treatment time, friction
force and aesthetic value. The frictional force created between the bracket and the
arch wire differs between the brackets. Passive SLBs` proposed to produce less
friction than conventional brackets and hence SLBs` are reported to minimise
treatment time. The Damon Q brackets used in our study are the passive type of
self-ligating brackets which are proved to deliver lighter forces and reduced friction.
Among conventional bracketing systems, certain amount of force is
eliminated in the form of friction and the remaining is utilised for tooth movement. As
passive SLBs` have nil frictional component, only a small amount of force is required
to initiate tooth movement. In fixed orthodontic therapy, lower forces are preferred
as it reduces the risk of internal root resorption and is less painfull53. Hence as the
range of tooth movement is increased among SLBs` because of reduced friction and
49
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
reduced force levels the treatment time is also shortened by a period of 3-6 months
based on the clinical complexity.
Stainless steel is extensively used in dentistry specially in manufacturing
the orthodontic materials like brackets, bands, arch wires etc. Two grades of
stainless steel used in dentistry are 304 and 316 stainless steel. Both can be
manufactured in standard or low carbon content.
Grade
Chromium %
Nickel %
304
18-20
8-10.5
304L
18-20
8-10.5
316
16-18
10-14
316L
16-18
10-14
Table 19: The metal Composition of different stainless steel grades
The orthodontic brackets and arch wires are usually made up of AISI type
316L austenitic type of stainless steel. Nickel and chromium alloys occupy the major
portion of its composition (in weight percent) along with other metal alloys like
carbon, manganese, chromium, molybdenum, copper, phosphorous, sulphur,
selenium, silicon, calcium. Nickel is added in greater proportions because of its
property of providing resistance to oxidation and corrosion; whereas chromium tends
50
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
to form a passive layer of chromium oxide on the surface of the stainless steel there
by providing resistance to corrosion.
ELEMENT
COMPOSITION
PROPERTY
IN WT%
C
0.026
Strength and Hardness
Si
0.37
Deoxidising agent
Mn
0.16
Toughness and Hardenability
Cr
16.55
Resistance to Corrosion and Oxidation
Fe
7.0
Core metal
Ni
10.0
Resistance to Corrosion and Oxidation
Mo
2.02
Resistance to Pitting
Table 20: Composition of 316L stainless steel and properties of each alloy
Essential metals like copper (Cu) and zinc (Zn) are required for metabolic
activities, whereas non-essential metals like chromium (Cr) and nickel (Ni) do not
play any positive role in biological activities. However, some studies have suggested
that Cr3+ may play a role in glucose metabolism(Pechova and Pavlata 2007; Ma’or et
al. 2015)59,60. Excessive amounts of both essential and non-essential metals can
harm the body's tissues54.
51
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
In recent times, there has been a lot of interest in the biocompatibility of
dental and orthodontic materials. Chemical approaches are essential for determining
the biocompatibility of orthodontic materials. Patients having orthodontic therapy
must be tested in order to determine their true exposure to the chemical elements
generated by metal alloys. Corrosion is one of the side effects of any metal alloy and
as most of the orthodontic brackets are made up of stainless steel, proper monitoring
of these orthodontic brackets for corrosion is essential . The studies conducted by
Rafeal et al (2020); Lagas et al (2017); Micukewic et al (2014); Natarajan et al
(2011); Sahoo et al (2011); Sfondrini et al (2008) etc were conducted to evaluate the
effect of corrosion of metal alloys used in manufacturing the orthodontic appliances.
Corrosion is an electrochemical reaction that causes a metal deteriorate.
Corrosion destroys metals by releasing metal ions directly into solution or by
gradually dissolving a surface coating, generally forming an oxide or sulphide on the
metal. The resultant compounds may cause irritation or dermatitis by triggering
inflammatory reactions in the soft tissues. Corrosion resistance is an important
feature of biocompatibility and it can be influenced by variety of factors like
manufacturing process, kind of alloy, surface properties of the metal and the
environment in which the metal is inserted. When the corrosion of orthodontic
appliances is severe, discoloration can be seen with the naked eye. Furthermore,
corrosion is a continuous process with cumulative effects. There may be a gradual
52
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
increase in surface rugosity or a build-up of corrosion products. This could result in
higher frictional resistance in orthodontic sliding mechanics, slowing down the
treatment therapy. The corrosion process is frequently undetectable and the
concentration of ions released is the only way to measure it14.
Nickel and chromium levels in biomarkers such as saliva2,40, hair26,45,
nail26,45 and oral mucosa5,46 have received a lot of attention. The amount of Ni
released from fixed orthodontic appliances may be less than the threshold necessary
to start an allergic reaction, at least in people who have not shown previous
hypersensitivity to metal ; but either way, a small level of free metal may also cause
allergies in people who are treated with fixed orthodontic appliances for two to three
years, because the symptoms of a Ni allergy may be seen over time.
The biological nature of the nail compared to the hair may have an
influence on metal concentration. Sukumar and Subramanian (2007) reported that
the high levels of elements observed in nails due to the nail samples are
recommended as best indicator showing maximum levels because of high
bioaccumulation, and external contamination.
53
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
Nickel is the most prevalent allergy in women. Chromium is the second
most common metal to cause allergic responses. Nickel has recently gained
prominence as a result of studies linking it to a variety of clinical disorders like
rashes, blisters etc17. Ni was discovered to impede leukocyte chemotaxis as well as
neutrophil stimulation to become aspherical at concentrations as low as 2.5 ng/mL
(ppm), resulting in inflammation7. Inflammation of the gums, tongue, gingival
hypertrophy, erythema multiforme, peeling of the lip epithelium and metallic taste in
the mouth are some of the signs of nickel and chromium allergy5,7,10,11.
The release of Nickel and chromium owing to electrochemical breakdown
in individuals undergoing fixed orthodontic treatment, has the potential to cause a
"hypersensitivity" response. An allergic reaction, also known as hypersensitization, is
an overactive immune response that happens when a recognised antigen is
encountered. Atopic contact dermatitis of the face and neck is the most common
manifestation of adverse hypersensitivity reactions, but mucosal and gingival
reactions can also occur. Treatment duration,
efficiency, treatment satisfaction,
overall health and quality of life are all affected when a patient has a hypersensitive
reaction. As a result, nickel and chromium can cause skin infections, asthma,
genotoxic and cytotoxic effects in human cells and tissues50.
54
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
The daily doses authorised for various elements according to the World
Health Organization are Ni 25–35 g/day, Cr 50–200 g/day and Ti 25–30 g/day. Ni is
absorbed by the gastrointestinal tract and eliminated mostly through the kidneys,
where almost 90% of it is excreted in urine48.
The sensitivity to chrome cobalt appliances was first described by
Darwin and Tarsitano. Svein investigated corrosion of base metal alloys by
immersing them in artificial saliva for two months and other researchers observed
similar results.
The nickel alloy composition prevents the quantity of nickel and other
metals released by electrochemical corrosion from reaching the dangerous level of
10 mg/kg body weight65. Nickel levels in human saliva range from 0.8 - 4.5 g/l and
nickel concentrations as low as 2.5 mg/ml were documented earlier hazardous to
human gingival cells in tissue culture. The usual food consumption of nickel is 200300 g/day. The lethal oral dose for nickel in humans is between 50 - 500 mg/kg body
weight66.
55
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
As a result of the corrosion of base metal alloys, chromate salts are also
produced which induce skin irritation and dermatitis. Chromium allergy caused by
oral contact is quite rare. The incidence of chromium allergy was found to be 10% in
males and 3% in females. Chromium is an essential ingredient for man's glucose
metabolism in amounts of 50-200 mg/day and the average dietary consumption of
chromium is 280 g/day with an estimated lethal dose of 50-70 mg/kg body weight.51.
Toxicology and environmental studies suggest that the indicators of
toxic metal exposure are generally locations of elimination or accumulation, where
the toxicant's concentration is evaluated in in - vivo experiments. Non-invasive
measures at the accumulation site (internal organs such as the liver and kidneys) are
frequently impossible. As a result, using excretion routes to establish biological
markers of exposure is proposed. Most of the metals found in orthodontic alloys can
be discharged into the mouth cavity as corrosion products, therefore, measuring
nickel concentration in body tissues in order to assess systemic absorption is a
sound idea9.
A material's hazardous effects are determined by two factors. These are
the exposure time and the concentration of the sample. In terms of exposure period,
research works conducted so far suggested metal leaching processes as time56
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
dependent. High metal ion levels were discovered 1–2 weeks after exposure to
metal appliances, then return to their original levels (Amini et al. 2012)8,35.
The wear and tear of an orthodontic appliance is caused by the constant
loading forces used to reposition the teeth. As a result, the fatigue in an orthodontic
appliance develops over time8.
Mineral analysis is commonly used to determine human chronic
exposure to a variety of elements including hazardous metals such as nickel and
chromium. In environmental and biological science, determining trace metal
concentrations is a frequent method. Atomic absorption spectroscopy (AAS),
inductively coupled plasma spectroscopy (ICP), neutron activation analysis (NAA),
emission spectroscopy and X-ray fluorescence are some of the analytical methods.
The most commonly used approach is AAS which combines flame and
electrothermal techniques.
We used graphite furnace atomic absorption spectroscopy commonly
known as Electrothermal Atomic Absorption Spectroscopy. A graphite-coated
furnace is used to evaporate the sample in this form of spectrometry. Free atoms
absorb light at frequencies or wavelengths that are characteristic of the element of
interest, which is the basis for the approach. The amount of light absorbed can be
linearly proportional to the concentration of analyte present within specified limits.
57
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
The application of high temperatures can yield free atoms of most elements from the
samples. The samples are placed in a tiny graphite or pyrolytic carbon coated
graphite tube which is heated to evaporate and atomize the analyte. The atoms
absorb ultraviolet or visible light and shift to higher electronic energy levels as. After
calibrating the equipment with known concentration standards, concentration
measurements are normally made.
Hence, by considering the severity of side effects which might occur by
metal ion release, we attempted to quantify and compare the amount of nickel and
chromium ion release from orthodontic appliances.
NAIL SAMPLES:
In our study, the concentration of nickel ions in nails is found to be
increased after 6 months of fixed orthodontic therapy usage which was found to be
statistically significant in both the conventional as well as the self-ligating groups.
Similarly the concentration of chromium ion is also found to be increased in the nails
after 6 months of fixed orthodontic therapy. The increased levels accounted to be
statistically significant in both the conventional and self-ligating groups. The nickel
and chromium ion concentrations in nails are within the normal range as proposed
by Jenkins in 1979.
58
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
Inter group comparison for nickel and chromium ion concentration
revealed a significant increase in the deposition of nickel and Chromium ions in nails
among self-ligating group.
The nickel and chromium ion concentration in nails was found to be
relatively lower than the nickel and chromium ion concentrations in hair which is in
accordance to a study conducted by Nowak and Chmielnicka (2013)50 who reported
that metal contents in nails is higher relative to hair for metals like lead, cadmium,
copper, iron, nickel and chromium.
When dental technicians and medical technicians were assessed for the
metal ion exposure in scalp hair and finger nails by Awadeen et al. in 2014 the dental
technicians showed presence of increased nickel and chromium ions release in both
hair and nail samples compared to the medical technicians which could possibly be
due to nature of work and environment of laboratory; dental technicians are exposed
to heavy metal through inhalation and skin absorption during fabrication of dental
prosthesis such as crown, bridge and the metal framework of removable partial
denture. The environment of dental laboratory may also have air borne
contamination51.
59
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
The nickel and chromium ion concentration in nails was found to be
relatively lower than the nickel and chromium ion concentrations in hair which is in
accordance to a study conducted by Nowak (2013)50.
A similar study was conducted by Martin-Camean et al, 2015; where they
analysed the hair strands among the patients receiving fixed orthodontic treatment
and compared with that of the non-orthodontic individuals and found that the
insignificant decline in nickel and chromium ion concentrations in the orthodontic
group for both nickel and chromium ions47.
HAIR SAMPLES:
In our study, the concentration of nickel ions in hair is found to be
increased after 6 months of fixed orthodontic therapy usage which was found to be
statistically significant in both the conventional as well as the self-ligating groups.
Similarly the concentration of chromium ion is also found to be increased in the hair
after 6 months of fixed orthodontic therapy. The increased levels accounted to be
statistically significant in both the conventional and self-ligating groups.
Inter group comparison for nickel and chromium ion concentration
revealed there is no significant increase in the deposition of nickel and Chromium
ions in hair among self-ligating group.
60
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
The release of nickel and chromium ions were elevated in hair strands
of patients undergoing fixed orthodontic treatment in a study conducted by Jamshidi
et al. 2018; which is in accordance with our study, indicating that the cytotoxic and
allergic effects of these ions9.
However the release of nickel ions into the hair strands of fixed
orthodontic patients revealed significant increase in the nickel ion concentration after
4 months of insertion of the fixed orthodontic appliance in a study conducted by
Masjedi et al. in 2017 which is in synchrony with our study but the time period in our
study is 6 months. It indicates that the metal ion increase is not time dependent and
significant increase can be seen even after 6 months after inserting the orthodontic
fixed appliance20.
The nickel ion concentration was found to be increased approximately by
two times in a study conducted by Abtahi et al9 in 2013 which is in much higher range
compared to our study. This may be attributed to the type of brackets used in the
study, their manufacturing process, the occupation of the samples, furthermore hair
is sensitive to external contamination with Ni. Some shampoos and many hair perm
dye bleach products leach Ni into the hair. Use of any hair accessories during the
period of study may be the reason for additional increase in nickel ion levels.
61
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
There was an increase the nickel and chromium ion concentrations in a
study conducted by Mudjari et al (2019) where they analysed the hair samples
among the patients receiving fixed orthodontic treatment. The increase of nickel
concentration in hair was statistically significant, whereas the increase in chromium
concentration was not statistically significant.
Our result was not in accordance with the study conducted by Levrini
(2006), who did not find any significant difference in nickel concentration among the
group of people who received orthodontic treatment with fixed appliances when
compared with non-orthodontic treatment receiving control group. This might be
because variation in the method of sample collection or digestion67.
Sturaro et al. (1994) investigated the exposure to Ni of steel mill workers
by analysis of the composition of scalp hair, in comparison with blood and urine.
Statistically significantly higher levels of Ni in all the matrices were found in comparison with control populations. The content of Ni in hair in the control group was
5.25mg/kg and increased 72 and 62% (9.02, 13.76 mg/kg) in hair of workers of steel
mill (quality and production department, respectively) and the content of Ni increased
with the time of employment. These results were well correlated with the composition
of the remaining matrices. This confirmed that the analysis of Ni in hair was a good
62
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
indicator of long-term exposure. Among 6 employees of production department,
three had abnormal liver function, one proteinuria and two exhibited allergic
dermatitis. Similar results were obtained for Cr ions.
Grabeklis et al. (2010) investigated the content of Ni in hair of chemical
plant workers. In the results, the authors underlined that the Ni level increased from
0.360 in the control to 0.459 mg/kg in the exposed population (28%). Also, the
content of Cr, Mn and Fe increased in the hair of employees. The differences
between the groups were statistically significant. These results were found to be in
accordance with our study.
ORAL MUCOSA SAMPLES:
In our study, the concentration of nickel ions in oral mucosa cells is
found to be increased after 6 months of fixed orthodontic therapy usage which was
found to be statistically significant
in both the conventional as well as the self-
ligating groups. Similarly the concentration of chromium ion is also found to be
increased in the oral mucosa cells after 6 months of fixed orthodontic therapy. The
increased levels accounted to be statistically significant in both the conventional and
self-ligating groups.
63
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
Inter group comparison for nickel and chromium ion concentration
revealed there is no significant increase in the deposition of nickel in oral mucosa
among self-ligating group but a significant increase in the deposition of Chromium
ions in oral mucosa among self-ligating group.
Though it is evident that there is increase in nickel and chromium
concentration in all compared body surfaces due to leaching of these metal ions that
is deposited in to various biomarkers in the body, the amount of ion concentration
which is being leached into the Oral mucosa is less compared to other biomarkers.
Amini et al. 2008 evaluated the nickel, chromium and cobalt ion
concentrations in oral mucosa cell samples of patients with fixed orthodontic therapy
and concluded that a significant increase in the nickel concentration is observed after
the orthodontic fixed appliance therapy compared with the controls which is similar to
the results obtained in our study. However, our findings of a statistically significant
increase in the chromium concentration are not in accordance with the study52. A
similar result was found in another study where a significant increase in both the
nickel and chromium concentration in the oral mucosa biomarker was found after 18
months of fixed orthodontic therapy.
The concentrations of nickel and chromium ions in the oral mucosa cells
after 30 days of fixed orthodontic treatment were not significantly higher than in the
control group in a study conducted by Natarajan et al. in 2011 which is in contrary to
64
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
our study which might be due to the varied method of collection and storage of the
samples or due to the high technique sensitive equipment required for detection the
metal ion levels which would also require a skilled professional to perform the
analysis. Due to the less amount of metal ion deposition seen in the oral mucosa
cells compared to the other biological samples (hair and finger nails) the increase in
the nickel and chromium metal ions is not reaching the significant levels 23.
A similar result was found a study by Quadras et al53 in 2018 where a
significant increase in the nickel and chromium concentration was found after 18
months of fixed orthodontic therapy in oral mucosa cells. Indicating that there is no
decline in the amount of metal ions being leached in to the oral cavity even at the
end of 18 months of fixed orthodontic treatment.
Comparison of metal release in self-ligating and conventional brackets
from the same manufacturer was done by Lúcio et al(2011) and they found that the
Self-ligating group released more nickel after 7 and 14 days, but less chromium after
14 days and less iron at the three experimental time intervals that is at 7days, 14
days and 21 days which is in contrast to our study where we found increased
released of chromium ions in self ligating group among nails and oral mucosa cells
whereas increase in nickel ions is seen among nails only68. The reason behind this is
may be because of invitro nature of the study where no treatment was performed on
the brackets at the end of the experiment and before the sample collection in order
65
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
to prevent the deposition of any oxides on the bracket surface as a result of the
corrosion process.
2+
The salivary Ni
and chromium concentrations were evaluated by
Sahoo et al. (2011) and compared among conventional (MBT preadjusted edgewise
TM
brackets) fixed appliance system, and self-ligating (SmartClip ) fixed appliance
2+
system. The self-ligating group accounted to higher release of Ni
levels compared
to the conventional group indicating that the NiTi clips may be the potential additional
source of nickel ion release2.
Kocadereli et al. reported that treatment by fixed orthodontic appliances
do not significantly affect the levels of nickel and chromium in the saliva. Neama et
al. did not detect significant differences in the Ni and Cr levels in the saliva of
patients with fixed orthodontic appliances. The causes of the differences in these
results could be attributed to the type and material used in the fabrication of
appliance, the properties of the used alloys, the exposed surface of the appliance
components and environmental factors, including the chemical composition,
temperature, pH, volume, microflora and also enzymatic activity of the saliva.
66
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
We also found that there was no significant effect of gender and age on
concentration of metal ions. Our results were found to be in accordance with Amini et
al. (2008) who also found no marked difference of the age and gender. Other studies
by Patryca Downariwicz et al.(2017) and Masjedi et al. (2017) also reported no link
between the age and gender and metal ion contents in the saliva and hair samples
between the control samples and the tested samples.
The measured quantities of
metal ions that are leached from fixed
orthodontic appliances are found to be far below the toxic levels. Thus, a systemic
toxic effect from orthodontic appliances is highly unlikely. However, even such small
quantities of metal ions can cause allergic reactions, especially because fixed
orthodontic appliances remain in the oral cavity for a long time. In our study, none of
the orthodontics patients presented clinical symptoms and the increase in metal
concentrations were lower when compared with their respective Tolerable daily
intake (TDI) as proposed by the Scientific Committee of Food, European
Commission.
The release of metal ions from orthodontic appliances cannot be fully
avoided; however, it is advisable to use materials which attribute lower amount of
metal ions release in to the mouth there by limiting the unwanted toxic effects of
these metal ions39.
67
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
Discussion
LIMITATIONS OF THE STUDY
Our study included analysis of mineral ion concentration in nail, hair and oral mucosa
cells similarly it could be assessed from other biomarkers like serum, saliva etc.
The duration of current study is 6 months, similarly the samples could have been
collected at frequent intervals and check if there is any change in the metal ion
concentration with respect to time duration. As self-ligating brackets have larger
metal surface area they are more prone to release higher concentrations of metal
ions, however in our study we tried to evaluate if these elevated concentrations are
reaching the toxic levels. Since it is an in-vivo study we followed the prescribed
archwire sequence for both the conventional (MBT prescription) and self-ligating
orthodontic brackets (Damon prescription). The difference in the archwire sequence
and the variations in the compositions of these archwires for both the prescriptions
might also alter the amount of metal ion release.
FUTURE SCOPE OF THE STUDY
The study can be continued to evaluate the concentrations of metal ions being
released from fixed orthodontic appliances at the end of 12 months, 18 months or at
the end of the orthodontic therapy to check if there is any elevation or decrease in
the metal ion concentrations.
68
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
SUMMARY AND
CONCLUSION
Summary and Conclusion
Summary and conclusion
The present study is carried out to determine and compare the concentrations of nickel
and chromium ion release in hair, nail and oral mucosa samples among conventional
metal brackets and self - ligating metal brackets before and after 6 months of fixed
mechanotherapy.
The following conclusions were formulated from our study:
1. There is statistically significant increase in the deposition of nickel and
chromium ions hair in both the metal conventional group and metal self-ligating
groups among all the samples i.e.; nail, hair and oral mucosa.
2. There is statistically significant increase in nickel ion concentration in nail
samples in self ligating group compared to the conventional group.
3. There is statistically significant increase in chromium ion concentration in nail
and oral mucosa cells in self ligating group compared to the conventional group.
However, the metal ion leaching from various orthodontic brackets
would depend on their method of manufacturing, quality of metal alloys being
used, composition of metal etc. Hence the range of metal ion concentration
being released by different brackets would be varied based on the
standardisation protocols and various other factors associated with each
manufacturer.
69
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
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61. Maijer R, Smith DC. Time savings with self-ligating brackets. J Clini Orthod.
1990 Jan;24(1):29-31.
62. Shivapuja PK, Berger J. A comparative study of conventional ligation and self-
ligation bracket systems. Am J Orthod Dentofacial Orthop. 1994 Nov
1;106(5):472-80.
63. McMullan
RE, Doubleday B, Muir JD, Harradine NW, Williams JK.
Development of a treatment outcome standard as a result of a clinical audit of
the outcome of fixed appliance therapy undertaken by hospital-based
consultant orthodontists in the UK. Br Dent J. 2003 Jan;194(2):81-4.
64. Bednar JR, Gruendeman GW. The influence of bracket design on moment
production during axial rotation. Am J Orthod Dentofacial Orthop. 1993 Sep
1;104(3):254-61.
65. de De Micheli SM, Riesgo O. Electrochemical study of corrosion in NiCr dental
alloys. Biomaterials. 1982 Oct 1;3(4):209-12.
66. Borhamy El Sayed M, Youssef El Bayoumy S, Abdala Ismael AE. The effect of
different types of space maintainers on minerals of saliva. A.J.D.S. 2018 Dec
Vol. 21, No. (5):497-502.
81
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
References
67. Levrini L, Lusvardi G, Gentile D. Nickel ions release in patients with fixed
orthodontic appliances. Minerva stomatol. 2006 Mar 1;55(3):115-21.
82
AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS, HAIR AND
ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
ANNEXURES
ANNEXURE - I
83
ANNEXURE - II
84
ANNEXURE - III
85
ANNEXURE - IV
PANINEEEYA MAHAVIDYALAYA INSTITUTE OF DENTAL SCIENCES AND RESERCH CENTRE, HYDERABAD
CONSENT FORM
RESEARCH TITTLE: AN IN VIVO STUDY COMPARING THE NICKEL AND CHROMIUM LEVELS IN NAILS,
HAIR AND ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELF-LIGATING METAL BRACKETS
RESERACHER: Dr. SURISETTY SAI PRIYA
I have been given information about the research “AN IN VIVO STUDY COMPARING THE NICKEL AND
CHROMIUM LEVELS IN NAILS, HAIR AND ORAL MUCOSA CELLS BETWEEN CONVENTIONAL AND SELFLIGATING METAL BRACKETS” and discussed the research project with Dr. Surisetty Sai Priya who is
conducting this research as a part of MDS degree supervised by Dr. Srikanth Aryasri in the Department
of Orthodontics & Dentofacial Orthopedics at Panineeya Institute of Dental Sciences, Hyderabad.
It has been brought to my knowledge that this research requires nail, hair and oral mucosa
samples and I have had an opportunity to ask Dr. Surisetty Sai Priya any questions I may have about
the research and my participation.
I understood my participation in this research is voluntary, I am free to refuse to participate in
this research any time. My refusal to participate or withdrawal of consent will not affect my treatment
or my relationship with the Department of Orthodontics & Dentofacial Orthopedics at Panineeya
Institute of Dental Sciences in any way.
If I have any enquiries about the research, I can contact Dr. Surisetty Sai Priya and Dr. Srikanth
Aryasri.
By signing below I am indicating my consent to :
Give personal details like my name, age, sex, previous dental history and details required for the
research to the best of my knowledge.
Nail, hair & oral mucosa sample
I understand that the data collected from my participation will be used for the thesis, presentation
and publication, I consent for it to be used in that manner.
Sign/ Thumb print
Date
…………………………………………
………./……../……………
86
ANNEXURE -V
पानी&नया महा*व,यालय दं त 1च3क5सा सं7थान *व9ान और अनस
ु ंधान क?@,
हैदराबाद
सहम&त पC
अनुसंधान का शीषFक: नाखून, बाल और बाल मूलाधार म, ब-ख और चू/ क1 सां4ता का
स6म7ण धातु के /प म, धातुओं के बत=न> और धातु का चयन करने वाले छोटे जीव: इन
HवHव अJययन म, शा6मल हM।
शोधाथH: डॉ। साL *Mया
मुझे शोध के बारे म, जानकारP दP गई है "धातु पारंपVरक कोWठक और धातु सेYफ 6लगे[टंग \ैकेट:
इन-Hववो ^टडी" के बीच नाखून, बाल और ओरल `यूकोसा को6शकाओं म, aनकेल और bो6मयम क1
सां4ता का तुलनाcमक मूYयांकन। .6सVरसeटP साf Hgया जो हैदराबाद के पैनेनेया इं^टPeयूट ऑफ
ड,टल साइंसेज म, ऑथjडॉिmटnस एंड ड,टोफे6शयल ऑथjपेpडnस Hवभाग म, डॉ। 7ीकांत आय=7ी क1
दे खरे ख म, एमडीएस pडsी के एक भाग के /प म, इस शोध का संचालन कर रहP हM।
यह मेरP जानकारP म, लाया गया है tक इस शोध के 6लए नाखून, बाल और ओरल `यूकोसा के
नमून> क1 आवuयकता होती है और मुझे डॉ। सूरती6सटP साf Hgया से कोई भी guन पूछने का
अवसर 6मला है, जो शोध और मेरP भागीदारP के बारे म, हो सकता है।
मुझे लगा tक इस शोध म, मेरP भागीदारP ^वैिvछक है, मM इस शोध म, tकसी भी समय भाग
लेने से इनकार करने के 6लए ^वतंw हूं। सहमaत म, भाग लेने या वापस लेने से इनकार करने से मेरे
उपचार या tकसी भी तरह से पैनीनेया इं^टPeयूट ऑफ ड,टल साइंसेज म, हyडी रोग Hवभाग और दं त
zचtकcसा Hवभाग के साथ मेरे Vरuते पर कोई असर नहPं पड़ेगा। य[द मुझे अनुसंधान के बारे म, कोई
पूछताछ करनी है, तो मM डॉ। सरू 6सटP साई Hgया और डॉ। 7ीकांत आय=7ी से संपक= कर सकता हूं।
नीचे ह^ता|र करके मM अपनी सहमaत का संकेत दे रहा हूं:
मेरे नाम, उ}, 6लंग, Hपछले दंत इaतहास और मेरे ~ान के सव=7ेWठ के 6लए अनस
ु ंधान के 6लए
आवuयक Hववरण जैसे •यिnतगत Hववरण द, ।
नाखून, बाल और मौ•खक uलेWमा का नमूना
साइन / थ`ब Hgंट
………………………………………
तारPख
…………/…………/……………
87
ANNEXURE - VI
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ౖ >?@ & BC:;DE :;ంటD, FGHదBాబKL
అనుమP పతSమT
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FGiD మBUయT ఓర9 మT`lmా :;9?లn .`a9 మBUయT `lopయం క=>?=qrష
s u vకw తxల=*తyక
మzల{+ంకనం: ఇ._|} అధ+యనం
పBUVWధక~6• €•ర‚: 6*కrD సుBUV„టr f mాi €ియ
S {
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„ r f mాi €ియ
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88