Evaluation of Restorative Procedures in Children following
Dental Rehabilitation under General Anesthesia
Omar A.S El Meligy*, Niveen S. Bakry**, Maha M.A. El Tantawi***
Abstract:
The present study was carried out to assess the success of oral rehabilitation
performed under general anesthesia (GA) in the "Special Care Unit", in the Department
of Pediatric and Community Dentistry, Faculty of Dentistry, Alexandria University, in
terms of restoration survival and absence of new/recurrent caries.
The study involved 93 healthy patients who had previously received oral
rehabilitation under GA in 2002-2003 and who were recalled for follow up examinations
after a time period ranging from 20-42 months. The mean age of the children was 3.79 ±
1.23 years. Data were collected from the children and their families through clinical
examination to assess the success of the restorations previously inserted under GA and
the presence of new caries. Background information about the education and occupation
of parents as well as dietary and oral hygiene habits and visits to dentists were also
collected through a questionnaire. Kaplan Meier survival analysis was performed to
determine the mean survival time in months of the different restorations. Cox regression
model was used to examine the effect of different variables on the time to restoration
failure. Logistic regression was used to study the effect of different variables on presence
of new caries in different surfaces.
The failure rate for anterior restorations was 49.3% and 12.7% for posterior
restorations with a total number of restorations failing = 207 out of 746 initially inserted.
The longest and shortest survival times were for strip crowns and anterior glass ionomer
for anterior restorations (38 and 32 months respectively) and for posterior restorations
stainless steel crowns and amalgam (40 and 36 months respectively). Not visiting the
dentist increased the hazards of failure of both anterior and posterior restorations (hazards
* **
***
Lecturers in Pediatric Dentistry, Faculty of Dentistry, Alexandria University
Lecturer in Dental Public Health, Faculty of Dentistry, Alexandria University
1
ratio = 1.54 and 1.89 respectively). Out of 42 subjects who had new caries lesions, 29 had
proximal lesions with a total number of new caries lesions on any surface = 53. Not
eating snacks significantly lowered the risk of new caries on any surface (odds ratio=
0.05, CI= 0.01, 0.19).
Strip crown and stainless steel crown had the longest survival times among
anterior and posterior restorations. In spite of the radical treatment delivered to these
children, they will need further treatment mostly to replace failed restorations.
Introduction:
Treatment under general anesthesia (GA) is an important modality for managing
young children in need of comprehensive restorative and surgical dental treatment. These
patients may need GA either due to their young age, limited ability to cooperate in a
normal dental setting, having special needs or due to extensive treatment required (1). It
has the advantage of permitting treatment in a single visit, allowing immediate relief of
pain and requiring little or no cooperation from the child (2-4). In addition, it is supposed
to provide the operator with the ideal working environment during delivery of treatment
which can lead to improved success rates for treatment. At the same time, treatment
under GA imposes on the operator the selection of radical treatment choices to avoid the
need for replacement of failed restorations. Other problems associated with dental
rehabilitation under GA is the high cost (5), small but significant risk of mortality (6,7)
and the risk of new and recurrent caries due to the initial high level of decay (1).
Furthermore, evidence suggests that restorations have a limited life span and that
once a tooth is restored, the filling is likely to be replaced many times producing what is
known as the “restorative cycle” (8). For treatment provided on the dental chair, it is
estimated that about 60% of all restorative work is concerned with replacing existing
restorations (9). In addition, children who receive oral rehabilitation under GA are
2
particularly susceptible to future high caries increment because they are high caries risk
by definition since their caries level is high and their dietary and oral hygiene habits are
unsatisfactory.
All these problems necessitate the objective evaluation of the process of oral
rehabilitation under GA to determine if the dentition restored to function under GA
remains in a functional and painless condition following such massive intervention.
Moreover, there is a need to examine both technical factors such as material and
technique used in addition to parent and patient factors which are known to affect
restoration longevity but have generally been less studied (10). Such factors include oral
hygiene and dietary habits, visits to dentist, patient's age and gender.
Therefore, this study was carried out to assess the success of oral rehabilitation
performed under GA in the "Special Care Unit" in the Department of Pediatric and
Community Dentistry, Faculty of Dentistry, Alexandria University, in terms of
restoration success and absence of new caries. Parent characteristics and patient attitude
was also analyzed to identify children at risk for repeated sessions of dental treatment.
Materials and Methods:
The present study was based on dental records of healthy patients who had
undergone comprehensive dental treatment under general anesthesia in the "Special Care
Unit", in the Pediatric and Community Dentistry Department, Faculty of Dentistry,
Alexandria University. Healthy children included were defined according to Sheller et al
(11) as those patients classified by attending anesthesiologist as ASA I or II at time of
surgery and having no developmental delays or disabilities. There were 32 patients'
3
records for operations performed in 2002 and 61 for patients receiving treatment in 2003.
Patients whose records were available were recalled for follow up in July- August 2005
and examined by a single examiner.
Recalled patients were provided with topical
fluoride gel application and oral hygiene instructions and referred to treatment if needed.
Collected data included date when oral rehabilitation was performed under GA,
patient's age at GA, number of sound, decayed and extracted teeth present at GA, as well
as details about the tooth and surface affected. In addition, patient's records included also
information about type of restoration inserted. At the follow up visit, the purpose of the
study was explained to the parent/s and consent for participation in the study was
obtained. Parents were given a questionnaire to fill in and- if needed- help was provided
to them to fill it. This questionnaire collected information about the education and job of
both father and mother. In addition, there were questions investigating the child's oral
hygiene habits (frequency and if it was supervised by parent or not) and dietary habits (if
the child snacked in between meals) in addition to frequency of visits to the dentist after
GA rehabilitation.
The child was examined to determine the fate of restorations previously inserted
under GA. Restoration failure was considered to occur if a restoration needed
replacement due to structural breakdown (fracture or dislodgement of the restoration), if
there was pulpal or dentoalveolar infection associated with the restored tooth or if there
was recurrent decay. Lost stainless steel crown was considered to be a failure. Intact
restorations without new caries at the time of follow up were considered to be successful.
Intra oral examination at follow up also checked for new carious lesions. Bitewing
radiographs were used to diagnose proximal caries. New carious lesions were recorded
4
clinically on smooth surfaces and pits and fissures. The behavior of the child at follow up
examination was rated according to Corah's Dental anxiety Scale (12).
Statistical analysis consisted of descriptive statistics for the study sample
characteristics and the status of teeth (decayed, extracted or filled). Analytical statistics
comprised Kaplan Meier survival analysis performed to determine the mean survival time
in months of the restoration types under study (13). Tarone Ware test for comparing the
equality of survival distributions was used. In this test, time points are weighted by the
square root of the number of cases at risk at each time point. Pairwise comparisons
between different restorations types was done for two separate strata: anterior and
posterior restorations separately. Cox regression model was used to examine the effect of
different variables on time to restoration failure. Backward stepwise selection method
was used for variables selection into model. Logistic regression analysis was used to
determine the predictors of new caries lesions in any surface, in pits and fissures and in
proximal surfaces. Bar graph was used to display the mean number of decayed surfaces
totally and by surface affected.
Results:
The study included 93 patients, 32 of whom had been treated under GA in 2002
(mean age=4.21 ± 1.22), and the remaining 61 in 2003 (mean age= 3.57 ± 1.11). The
interval between the time when the first operation was performed under GA and the time
when children were examined at follow up ranged from 20- 42 months.
Table 1 shows the sociodemographic, oral hygiene, dietary habits and dental
visiting of the study sample. The majority of children in the study had mothers who were
5
housewives (66.7%) and who had secondary school level or higher education (68.8%),
had fathers who worked as skilled workers (75.3%) and had secondary school level or
higher education (78.5%). The majority of children exhibited good behavior during
examination at follow up (76.3%) reported brushing frequently (71%) and that this
brushing was under supervision (52.7%). They also reported visiting the dentist regularly
(57%) and eating snacks (58.1%).
Table 1: Sociodemographic, oral hygiene, dietary habits and dental visits of the study
sample
Variables
Categories
Frequency
Percent
Occupation of mother
Housewife
62
66.7
Professional
10
10.8
Skilled worker
21
22.6
Professional
23
24.8
Skilled worker
70
75.3
Secondary / diploma or more
64
68.8
Primary
29
31.2
Secondary / diploma or more
73
78.5
Primary
20
21.5
Good
71
76.3
Bad
22
23.7
Frequent
66
71
Not frequent
27
29
49
52.7
Occupation of father
Education of mother
Education of father
Behavior in clinic
Brushing frequency
Supervision
of Yes
brushing
No
44
47.3
Visits to dentists
Yes
53
57
No
40
43
Yes
54
58.1
No
39
41.9
Eating snacks
6
Table 2 shows the number of restorations inserted, percent failed, percent
survived as well as the mean survival time in months. Among the different types of
anterior restorations inserted, the longest survival rates was for strip crown followed by
composite and lastly anterior glass ionomer (survival rates= 64.5%, 47% and 43.8
respectively). No statistically significant differences existed between the mean survival
time of composite (33 months) and that of anterior glass ionomer (32 months) (p value
>0.5). However, the difference between the mean survival time of strip crown (38
months) and both composite and glass ionomer was statistically significant (p<0.05).
Among the posterior restorations inserted the longest survival rates were for stainless
steel crown, posterior glass ionomer and then lastly amalgam restorations (91.7%, 81.4%
and 76.5% respectively). For posterior restorations, there was a statistically significant
difference between the mean survival time of stainless steel crowns (40 months) and both
posterior glass ionomer (39 months) and amalgam (36 months) (p<0.05) but not between
amalgam and posterior glass ionomer (p>0.05). The difference between the survival times
of anterior and posterior restorations was also statistically significant (p<0.05). Figures 1
and 2 show the cumulative survival functions plots of anterior and posterior restorations
in the study.
7
Table 2: Number of restorations inserted, percent failed, percent survived and mean
survival time in months
Anterior
Type of restoration
Inserted:
Failed:
/
N (% of N
posterior
total)
(%
Survived:
Mean
of N (% of survival
inserted)
inserted)
time
in
months
(95% CI)*
Anterior
Strip crown
76 (24.8)
27 (35.5)
49 (64.5)
38 (37, 40)
Composite
166 (54.2)
88 (53)
78 (47)
33 (32, 34)
36 (56.2)
28 (43.8)
32 (29, 34)
151 (49.3)
155 (50.7) 34 (33, 35)
steel 289 (65.7)
24 (8.3)
265 (91.7) 40 (39, 41)
glass 70 (15.9)
13 (18.6)
57 (81.4)
39 (37, 41)
Amalgam
81 (18.4)
19 (23.5)
62 (76.5)
36 (34, 37)
Total
440
56 (12.7)
384 (87.3) 39 (38, 40)
746
207 (27.7)
539 (72.3) 37 (36, 37)
Anterior
glass 64 (20.9)
ionomer
Total
Posterior
Stainless
306
crown
Posterior
ionomer
Total anterior and posterior
* CI: confidence interval
8
Figure 1: Cumulative survival plot of anterior restorations
Survival Functions for posterior restorations
1.0
amalgam
stainless steel crown
posterior glass
ionomer
censored amalgam
censored st st crown
censored posterior
glass ionomer
Cum Survival
0.8
0.6
0.4
0.2
0.0
20
25
30
35
40
45
time in months
Figure 2: Cumulative survival plot of posterior restorations
9
Table 3 shows the factors significantly affecting time to failure of anterior and
posterior restorations. Strip crown had one third the hazards ratio of failure compared to
other anterior restorations (HR=0.33, CI= 0.20, 0.55). Absence of new caries decreased
the hazards ratio of anterior restorations (HR= 0.49, CI= 0.33, 0.73). Not visiting the
dentist regularly increased the hazards ratio for both anterior and posterior restorations
(HR = 1.54 and 1.89, CI = 1.05, 2.26 and 1.08, 3.32 respectively). Not eating snacks
decreased the hazards ratio of posterior restoration (HR= 0.42, CI= 0.21, 0.83).
Table 3: Factors significantly affecting failure of restorations (Cox proportional hazards
model)
Anterior
/ Variables
posterior
Wald chi P value
HR
95% CI
<0.0001*
0.33
0.20, 0.55
<0.0001*
0.49
0.33, 0.73
0.03*
1.54
1.05, 2.26
0.03*
1.89
1.08, 3.32
0.02*
0.42
0.21, 0.83
square
Anterior
Using strip crown
18.2
restoration
Not having new 12.45
caries
Not visiting the 4.93
dentist
Posterior
Not visiting the 4.90
restorations
dentist
Not eating snacks
6.18
HR= hazards ratio, CI= confidence interval
*= Statistically significant at p ≤ 0.05
Table 4 shows the number of new caries, fillings and extraction in the study
sample. The majority of new caries occurred in proximal surfaces (mean ± SD= 0.31 ±
0.47, percent of subjects= 31.2%, percent of total surfaces = 1.66%). Almost half of the
patients recalled for follow up (42 patients forming 45.2% of the study sample) were
10
found to have new caries lesions. There were 53 new caries lesions (3.03% of all teeth in
the study). Figure 3 shows the mean number of teeth with new caries in all surfaces, in
pits and fissures, in proximal surfaces and in smooth surfaces.
Table 4: New carious lesions, previous fillings and missing teeth in study sample
Min
Max
Mean ± SD
Subjects with Surfaces with
condition:
condition:
N (%)
N (%)
New pit and fissure caries
0
2
0.24 ± 0.52
18 (19.4)
22 (1.26)
New proximal caries
0
1
0.31 ± 0.47
29 (31.2)
29 (1.66)
New smooth caries
0
1
0.02 ± 0.15
2 (2.2)
2 (0.11)
New total caries
0
3
0.57 ± 0.71
42 (45.2)
53 (3.03)
Missing
0
10
0.96 ± 1.85
32 (34.4)
110 (6.3)
Filled
2
18
8.25 ± 3.55
93 (100)
746 (42.7)
DMF
3
28
9.77 ± 4.16
93 (100)
909 (52.03)
Sound
1
17
10.3 ± 3.93
93 (100)
838 (47.97)
All surfaces
14
20
19.85 ± 0.74 -
1747 (100)
11
0.6
Mean number of teeth
0.5
0.4
0.3
0.2
0.1
0
total new caries
new pit and fissure
caries
new proximal
caries
new smooth caries
Figure 3: Mean number of teeth with new caries in different sites
Table 5 shows the factors significantly affecting the occurrence of new caries
lesions. Because there were only two new smooth surface lesions, they were not included
in the logistic regression analysis. For caries in pits and fissures, in proximal surfaces or
in any surface, not eating snacks significantly reduced the risk of new caries (OR= 0.03,
CI= 0.003, 0.38, OR= 0.16, CI= 0.05, 0.54 and OR= 0.05, CI= 0.01, 0.19 respectively).
12
Table 5: Factors significantly affecting occurrence of new lesions (logistic regression
model):
Caries
Predictor
Wald chi P value
OR
CI
square
Pit and fissure caries
Not eating snacks
7.58
0.006*
0.03 0.003, 0.38
Proximal caries
Not eating snacks
8.64
0.003*
0.16 0.05, 0.54
Any caries
Not eating snacks
17.94
<0.0001*
0.05 0.01, 0.19
OR= odds ratio, CI= confidence interval,
*= Statistically significant at p ≤ 0.05
Discussion:
The study involved data from records and clinical examinations of 93 healthy
patients receiving oral rehabilitation under GA. Almost one third of these patients (29%)
did not brush regularly and 43% of them did not visit a dentist regularly for check ups
after GA. The majority (58.1%) still had snacks between meals. In view of the radical
treatment these children had undergone under GA and the cost involved, their dietary and
oral hygiene habits were expected to be better, but it seems that dental treatment under
GA has little effect on promoting oral health by itself (14). Oral health education and
prevention should closely follow GA to educate the patient and ensure an environment
promoting restoration success.
Failed anterior and posterior restorations formed 27.7% of all restorations
previously inserted under GA. Several studies have shown that the percentage of failed
restorations in primary teeth is in the range 20-30% (15, 16). Posterior restorations
generally survived longer than anterior restorations with nearly half (49.3%) of the latter
failing after three and half years of insertion. Composite was the most frequently inserted
13
anterior restoration, but nearly half of these restorations failed. Sheller et al (11) reported
a similar failure rate (55%) of multisurface composite restorations in patients who
required another GA session for dental treatment. Strip crown is the first choice of many
clinicians due to superior esthetics and ease of repair if the crown should subsequently
chip or fracture. The success rate of composite strip crown in the present study was
64.5% which is similar or somewhat higher to the 49% success rate reported by Tate et al
(17). GA allows treatment to be done under good condition of isolation which enhances
composite retention. However, the rate of success of composite restorations was 47%.
Composite was used to restore class III and class V. it would appear that when removing
interproximal or cervical decay on primary incisors, keeping a very small conservative
preparation may not be the best choice. Pulp chamber of primary incisors is
comparatively large and the enamel and dentin are thin. Consequently the depth of cavity
preparation becomes very shallow, which may result in insufficient amount of restorative
material, predisposing to loss of restoration (18). Therefore, it has been recommended
that even small class III in primary teeth should have a labial or lingual dove tail or
should incorporate a large surfaces area for bonding to enhance retention (19). The
success rate of glass ionomer restorations was 43.8%. These results were comparable to
the results of Basso and Edelberg (20) and Lo and Holmgren (21) who evaluated long
term success of glass ionomer cement placed into class III preparation which ranged from
20-73% after one year and only 14% after 30 months respectively. Glass ionomer
cements are useful in situations where economics or access to care is a significant
problem but they can not deliver predictable and esthetic restoration of primary incisors.
14
Distribution of posterior restorations indicates that clinicians in the Special Care
Unit favor maximum coverage using stainless steel crown since stainless steel crowns
were the most frequently inserted posterior restoration and it seems that their choice was
justified since it was the most successful among all posterior restorations. Sheller et al
(11) also reported that stainless steel crowns had the highest success rates (93% for
stainless steel crowns alone and 83% for stainless steel crowns with pulp treatment) in
children who needed another GA session for dental treatment. Tate et al (17) reported an
almost identical small failure rate (8%) for stainless steel crown inserted under GA after a
follow up period ranging from 3 to 11 years. Studies evaluating the success and longevity
of different restorations in a routine dental setting support the superiority of stainless steel
crowns (22). Similar results were also concluded from studies of outcomes of restorations
placed under GA (23). The choice of material for posterior restorations indicates a move
towards posterior glass ionomer which in the present study was almost equal to the
number of inserted amalgam restorations. The same situation is starting to show in
different areas of the world, especially in Scandinavia and Germany (24). Part of the
reason for this phenomenon may be due to the potential cariostatic effect of glass
ionomer cements owing to the release of fluoride. However, no such effect has been
shown in comparative studies of amalgam and glass ionomers (24), or in the present
study. Similar to the present study, Mjor et al (24) in a practice based study found that the
median age of replaced amalgam in children was 3 years, but their study found that the
mean age of amalgam was significantly higher than that of glass ionomer restorations
which is contrary to our findings. This could be explained by the fact that in the present
study, posterior glass ionomer was used for simple class I cavities which may have
15
increased its success rate compared to amalgam which was used in more extensive cases.
A review by Hickel et al (25) found that the failure rate of posterior restorations ranged
from 0-14%, for stainless steel crown and 0-35.3% for amalgam which is in accordance
with our results.
Restoration failure was affected by some technical factors such as choice of
restoration; so that using strip crown significantly reduced the hazards of failure in
anterior teeth. Other behavioral factors had significant effect on failure; so that not
visiting the dentist increased the hazards of failure for both anterior and posterior
restorations while avoiding snacks reduced the hazards of posterior restoration failure.
Absence of caries reduced the hazards of anterior restoration failure.
Mjor et al (24) found that the main reason for replacement of restorations in
primary teeth was caries (ranging from 48% in conventional glass ionomer to 53% in
amalgam) followed by fracture of restorations. Similarly, several studies confirm that
diagnosis of caries is the most common reason for the replacement of restorations (10).
Almeida et al (26) compared new caries lesions in patients with early childhood
caries (ECC) and controls who were initially caries free. Both groups were followed up
for more than two years. New pit and fissure caries occurred in 26% of the controls
compared to 40% of cases with ECC, while new smooth surface caries occurred in 13%
of controls compared to 60% of cases. The prevalence of new pit and fissure caries in the
present study is thus considered comparatively lower than that reported in their study,
while the prevalence of new smooth caries is similar to that reported in their study. The
one factor significantly affecting absence of new caries lesions in any surface in the
present study was avoiding snacks.
16
Appreciation of the multifactorial nature of dental caries is important when
developing a treatment plan. Child, parent and dentist all influence the outcomes of
treatment. A child will not voluntarily alter his/her diet or improve his/ her oral hygiene
habits. The responsibility for these changes rest with the care giver. It may be of value to
actively pursue these caregivers and promote a preventive agenda emphasizing
termination of snacks, use of fluoride, increased tooth brushing by parents and regular
professional dental recalls. Furthermore, the successful outcome of stainless steel crowns,
strip crowns and subjects' high caries recurrence rate support the view that the operating
room is not the place for conservative dentistry.
Conclusions:
Strip crown and stainless steel crown had the longest survival times among
anterior and posterior restorations. In spite of the radical treatment delivered to these
children, they will need further treatment mostly to replace failed restorations.
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