Protocol (Final)
Title
Conventional radiography and cross sectional imaging
when planning dental implants in the anterior edentulous
mandible to support an overdenture: a systematic review.
Details of Authors
Andrew Martyn Shelley
University of Leeds, UK
Anne-Marie Glenny
University of Manchester, UK
Michaela Goodwin
University of Manchester, UK
Keith Horner
University of Manchester, UK
Paul Brunton
University of Leeds, UK
Corresponding author
Andrew Shelley
3 Yew Tree Park Road
Cheadle Hulme
Cheadle
Cheshire
SK8 7EP
United Kingdom
Telephone numbers
Home
– 0161 485 3609
Place of work
– 0161 320 4230
Fax
– 0161 320 8134
e-mail - andrew@andrewshelley.com
Contents
1
Background.................................................................................................................... 1
2
Review question............................................................................................................. 3
3
Inclusion criteria ............................................................................................................. 4
4
Search Strategy ............................................................................................................. 6
5
Study selection .............................................................................................................. 8
6
Data extraction ............................................................................................................. 10
7
Quality assessment ...................................................................................................... 11
8
Data synthesis ............................................................................................................. 12
9
Discussion ................................................................................................................... 12
10
Dissemination ........................................................................................................... 12
11
Appendices .............................................................................................................. 13
12
References ............................................................................................................... 20
i
1 Background
Implant supported overdentures in the edentulous anterior mandible are considered the
treatment of choice in many cases of severe or moderate alveolar resorption.1 For example,
the provision of two implants in the lower canine regions with stud attachments can be a
relatively simple way of addressing otherwise insoluble denture problems. The form of the
anterior mandible varies greatly according to the degree and pattern of resorption. This can
result in narrow, shallow or knife edge ridges which can complicate implant placement. 2
Perforation of the lingual cortical plate during preparation for placement of dental implants
has the potential to cause severe bleeding and a life threatening upper airway obstruction. At
least 20 such case reports appear in the literature.3-20. Some authors have expressed the
opinion that preoperative cross sectional imaging is advisable, or should be routine, to
reduce the likelihood of such an event.2, 21, 22 Nonetheless, there is a responsibility to
maximise the diagnostic value of imaging whilst keeping radiation doses as low as
reasonably achievable.23 Cone beam CT is a significant improvement on multi-slice CT in
terms of radiation dose. Notwithstanding, whilst individual machines vary, cone beam CT
still has an effective dose around ten times that of, for example, a panoramic view.24 To
enable planning of dental implant therapy, an appreciation of the form of the anterior
mandible may also be gained through conventional radiography, preoperative palpation or
by peri-operative surgical exploration.2 It is unclear whether the preoperative availability of
cross sectional imaging would have an impact on the assessment, treatment or outcome in
such cases.
A hierarchy of levels of efficacy has been proposed for the evaluation of diagnostic
imaging.25-27 Fryback and Thornbury proposed six levels: technical efficacy, diagnostic
accuracy efficacy, diagnostic thinking efficacy, therapeutic efficacy, patient outcome efficacy
and societal efficacy.28 Many studies have been conducted to investigate technical efficacy
and diagnostic accuracy efficacy of cross sectional imaging methods and these have been
the subject of systematic review. 29-32 Nevertheless, the impact of cross sectional imaging on
assessment, treatment and outcome of dental implant therapy would be the subject of
evaluation at higher levels of efficacy. A scoping exercise revealed that there are far fewer
studies which evaluate the efficacy of diagnostic imaging at these higher levels and no
systematic reviews have been identified.
1
Guideline documents on selection criteria for imaging prior to implant placement have been
issued by several authorities.24, 33-36 Notwithstanding, guidelines on selection of images for
dental implantology are often non-specific, stated in vague terms and open to wide
interpretation. A previous study has demonstrated that the pattern of prescription of imaging
in such circumstances is chaotic.37 There is no agreement amongst implant practitioners in
the North West of England. The aim of this review is to help fill the gap in knowledge with
regard to the higher levels of efficacy of imaging methods prior to dental implant placement
in the edentulous anterior mandible and to inform guideline development.
2
2 Review question
1. Does the use of cross sectional imaging prior to dental implant placement in the
anterior edentulous mandible have any impact on diagnostic thinking, compared to
conventional imaging alone, when an implant retained overdenture is planned?
2. Does the use of cross sectional imaging prior to dental implant placement in the
anterior edentulous mandible have any impact on treatment planning, compared to
conventional imaging alone, when an implant retained overdenture is planned?
3. Does the use of cross sectional imaging prior to dental implant placement in the
anterior edentulous mandible have any impact on outcome, compared to
conventional imaging alone, when an implant retained overdenture is planned?
3
3 Inclusion criteria
PICOS elements
Participants/ Population
►
Human
►
In vivo or in vitro using radiographic phantoms
►
Complete mandibular edentulism
►
Implants are planned for the interforaminal region which will support a complete
lower overdenture.
►
If insufficient studies are identified, then those which investigate dental implant
placement anywhere in the mouth, but including the anterior mandible, will be
included.
Interventions
►
Cross sectional imaging, of all types, prior to dental implant placement.
Comparators
►
Conventional two dimensional radiography prior to dental implant placement.
Outcomes
►
Diagnostic thinking, therapeutic efficacy or patient outcome as defined by Fryback
and Thornbury 28: (See Appendix A) Studies which are concerned only with Fryback
and Thorbury’s lower levels, technical efficacy or diagnostic accuracy efficacy, will
not be included. Similarly, any studies which analyse only the higher level of societal
efficacy will not be included.
4
Study design
Studies will be included where the primary purpose is cross sectional imaging for
assessment prior to dental implant placement rather than being primarily for the construction
of a computer generated surgical guide.
The following study designs will be considered
►
Before and after studies, controlled or uncontrolled
►
Case control studies
►
Cohort studies
►
Randomised controlled studies
►
Non randomised controlled studies
Language
Studies in the English language
Studies where there is an English language abstract and a translation of the full paper can
be identified.
Publication types
►
Peer reviewed journals
►
Non peer reviewed journals
►
Reports
►
Book chapters
►
Conference abstracts
►
Theses
►
Informal reports and on-going studies
5
4 Search Strategy
Electronic search of databases
- A pilot study has been conducted and is presented separately. The conclusion
was that the following search terms should be used without date restriction.
(Dental Implant* OR Implant dentistry OR oral implant*) AND (Radiograph* OR Radiolog*
OR Tomograph* OR Imag*) AND (planning OR assessment) AND (compar* OR chang*)
-The following electronic databases will be searched:
o
Pubmed
o
Embase
o
Cochrane CENTRAL library
Additional searches
Trial searches of the following sources are presented separately
►
►
Reference tracking
o
Search reference sections of studies identified in the electronic search
o
Search reference sections of published guideline documents
Citation tracking
o
Citation tracking software

Web of Knowledge Science Citation Index
– see trial search in pilot study
►
Hand searching
o
Search contents pages from key journals identified in electronic search
– see trial search in pilot study
6
►
Grey literature
o
Hand search key conference proceedings. IADR website
– see trial search in pilot study
o
Opengrey website
– see trial search in pilot study
o
Trials register – www.clinicaltrials.gov www.who.int/trialsearch/
– see trial searches in pilot study
o
Email requests to Departments of Dental Radiology in the UK?
o
Systematic review website – canvas for unpublished studies
– see website www.andrewshelley.com/systematic_review.html
►
Thesis searching
o
Dissertation and Thesis data base search

Proquest

EThOS
Reporting
o
Contemporaneous recording of all stages of the process and the results
7
5 Study selection
STAGE 1
AMS will review titles to exclude those studies which are clearly irrelevant to this systematic
review. This will be done by comparison of the titles with the inclusion criteria. Remaining
studies will pass to stage 2.
STAGE 2
AMS will review abstracts to identify relevant articles that will be retrieved for full text review
in Stage 3. This will be done by comparison of the studies with the inclusion criteria. Where
studies are clearly irrelevant no further documentation will be carried out. Where a study
narrowly fails to meet the inclusion criteria, the reason will be recorded. In cases where the
abstract provides insufficient detail the study will pass to stage 3 where the full text will be
examined.
In those cases where a study narrowly fails to meet the inclusion criteria, the decisions will
be re-examined by a second reviewer.
In practice, it is likely that stages 1 and 2 will be carried out simultaneously
STAGE 3
Where studies appear to meet the inclusion criteria, or where a decision cannot be made on
the title and abstract alone, full papers will be obtained for detailed assessment against the
inclusion criteria. At this stage, duplicate studies will be removed or, where studies are
published in multiple parts, individual papers will be combined. Where further information is
required, that is not included in a study report, authors will be contacted for clarification.
Stage 3 will be carried out independently by AMS and AMG. Where there is disagreement,
this will be resolved by consensus. Where consensus cannot be reached, a third reviewer,
KH, will be consulted.
8
Reviewers will not be blinded to authors, institution or study results during the study
selection process. This has been demonstrated to be of limited value whilst considerably
increasing the difficulty of the process of study selection.38, 39
A PRISMA flow diagram will be constructed to record the process of study selection.
(Preferred Reporting Items for Systematic Reviews and Meta-Analyses) See Appendix B
9
6 Data extraction
Data extraction from included studies will be carried out independently by AMS and one
other reviewer. This protocol has been demonstrated to result in fewer errors than data
extraction by a single reviewer.40 Study characteristics and outcome results will be collected
using a standardised form. (Appendix C) Any discrepancies will be resolved by discussion
and, where necessary, by involvement of a third reviewer.
The development of the data extraction form is the result of a pilot study which is reported
separately. The data extraction form has both a printed version and an electronic version in
Microsoft Excel. It is the intention to use the Excel form for more convenient manipulation
and analysis of data.
10
7 Quality assessment
The methodological quality of each study will be assessed using the tool developed by
Meads and Davenport for diagnostic before-after studies.41 This, in turn, is a modification of
The Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool developed by the
NHS centre for Reviews and Dissemination at the University of York, UK.42 The tool
appraises study quality by indicating the presence or absence of 12 key criteria through a
series of questions that are answered as ’yes’, ’no’, ’unclear’ or ‘not applicable’. In addition
there are two questions for which a subjective judgement of quality is made. For example,
Meads and Davenport added the question, “Who performed the clinical evaluation and
image analysis?” In a different systematic review protocol, concerning three dimensional
imaging, Josephson et al similarly modified QUADAS by adding a question about the level of
training of evaluators.43 Whilst the content is the same, the presentation of Meads’ and
Davenport’s tool has been adapted for this systematic review. This adaptation allows a
common visual interpretation of the results of all questions. The quality assessment tool is
presented in Appendix D.
Quality assessment will be carried out independently by AMS and one other reviewer.
Where there is disagreement, this will be resolved by consensus. Where consensus cannot
be reached, a third reviewer will be consulted.
A pilot study of the quality assessment tool has been carried out and is presented
separately.
11
8 Data synthesis
A narrative synthesis will be carried out under the following headings:
►
Study characteristics

►
Core synthesis

►
Study characteristics will be described by means of narrative and tabulation
Study results will be synthesised by tabulation using appropriate colour
coding
Exploratory synthesis

Relationships within the data will be explored and differences considered
A pilot study has been carried out using the studies identified in the rapid scoping exercise.
This is presented separately.
9 Discussion
The robustness of the synthesis will be explored together with a discussion of the strengths
and weaknesses of the review.
10 Dissemination
The following dissemination strategy will be undertaken:
►
►
►
►
Make the review accessible through publication in an academic journal.
Alert potentially interested parties to the existence of the review
Present findings at academic conferences where appropriate
Make details available on the systematic review website though subject to any
publication restrictions appropriate to academic publishing.
12
11 Appendices
13
Appendix A
Diagnostic thinking, therapeutic efficacy or patient outcome as defined by Fryback and
Thornbury
Question 1
Level 3. Diagnostic thinking efficacy 28
►
Number of cases in a series in which image judged helpful to making the diagnosis
►
Entropy change in differential diagnosis probability distribution
►
Difference in clinicians’ subjectively estimated diagnosis probabilities pre to post test
information
►
Empirical subjective log-likelihood ratio for test positive and negative in a case series
Question 2
Level 4. Therapeutic efficacy 28
►
Number of times image judged helpful in planning management of the patient in a
case series
►
Percentage of times procedure avoided due to image information
►
Number of times therapy planned pretest changed after image information was
obtained
►
Number of times clinicians’ prospectively stated therapeutic choices changed after
test information
Question 3
Level 5. Patient outcome efficacy 28
►
Percentage of patients improved with test compared with without test
►
Morbidity or procedures avoided after having image information
►
Change in quality adjusted life expectancy
►
Expected value of test information in quality adjusted life years (QALYs)
►
Cost per QALY saved with image information
14
Appendix B PRISMA flow diagram
15
APPENDIX C – Data extraction form (printed version)
Data Extraction Form v2
Name of assessor
(Adapted from Albon et al.)
Where the required information is not stated in the study report write NS
Study details
Author; year, trial name
Country(ies) and years of recruitment
Study design
Area of the mouth studied
Conventional imaging technique used
X sectional or 3D imaging technique used
Setting (practice, hospital etc)
Comments:
Patient characteristics
Population
Number of patients in study
Age (provide all information from study eg range,
SD etc)
Gender – state percentage male (%)
State presenting problem if not partial or
complete edentulism
Inclusion/exclusion criteria
Comments:
16
Evaluator characteristics
Number of evaluators
Types of evaluator (surgeon, radiologist etc)
Comments:
Interventions
Number of excluded patients
Number of patients after exclusions
Implant manufacturer(s)
Lengths and widths of implants available for
selection
Number of implants placed
How many anterior mandible?
How many posterior mandible?
How many anterior maxilla?
How many posterior maxilla?
Did evaluators carry out a clinical examination?
If no clinical examination carried out, was other
clinical information available to evaluators (eg.
study casts, clinical findings etc)
Comments:
17
Outcomes for analysis
What were the outcome measures?
(complete the sections which apply below)
If outcome measure is simply selection of a different implant
In how many sites was a different implant
selected after X sectional or 3D imaging
evaluated?
If outcome specifies selection of a different length or width
In how many sites was a different length of
implant selected after X sectional or 3D imaging
evaluated?
In how many sites was a different width of
implant selected after X sectional or 3D imaging
evaluated?
If outcome specifies selection of a longer, shorter, wider or narrower implant
In how many sites was a longer implant chosen
after X sectional or 3D imaging evaluated?
In how many sites was a shorter implant chosen
after X sectional or 3D imaging evaluated?
In how many sites was a wider implant chosen
after X sectional or 3D imaging evaluated?
In how many sites was a narrower implant
chosen after X sectional or 3D imaging
evaluated?
If outcome specifies prescription of additional procedures such as bone grafting, sinus lifting etc.
In how many sites was bone grafting prescribed
after X sectional or 3D imaging but not after
conventional imaging?
In how many sites was bone augmentation
prescribed after conventional imaging but not
after X sectional or 3D imaging?
In how many sites were other surgical procedures
prescribed after conventional imaging but not
after X sectional or 3D imaging?
In how many sites were other surgical procedures
prescribed after conventional imaging but not
after X sectional or 3D imaging?
Comments:
Can outcome data for anterior mandible only be
analysed?
18
Appendix D - Quality Assessment Tool (Modified from Quadas 1 by Meads & Davenport)
Author
Year
Study title
No.
Item
N/A
1
Was the spectrum of patients representative of patients who will
receive imaging in practice?
2
Were the selection criteria clearly described?
6
Is the period between conventional imaging and 3D imaging short
enough to be reasonably sure that the target condition did not
change between the two tests?
Did the whole sample or a random selection of the sample receive
verification using a reference standard of diagnosis?
(Yes for whole sample or random selection. No if neither.)
Did the patients receive the same 3D imaging regardless of
conventional imaging?
8
Was the execution of the conventional imaging described in
sufficient detail to permit replication of the test?
9
Was the execution of the 3D imaging described in sufficient detail to
permit its replication?
10
Were the conventional imaging results interpreted without
knowledge of the results of the 3D imaging?
11
Were the 3D imaging results interpreted without knowledge of the
conventional imaging?
4
5
12
Were the same clinical results available when imaging results were
interpreted as would be available when the imaging is used in
practice?
13
Were uninterpretable/intermediate imaging results reported?
14
Were withdrawals from the study explained?
A
Were patients recruited consecutively?
C
Was the study and/or collection of clinical variables conducted
prospectively?
B
What was the explanation for patients
who did not receive 3D imaging?
(Green for good quality, red for poor quality.)
D
Who performed the clinical evaluation
and image analysis?
(Green for good quality, red for poor quality.)
Numbering is unchanged from original sources. Numbered items are from Quadas 1.
Questions 3 & 7 were removed by Meads and Davenport
Letters are additional questions from Meads and Davenport
Overall subjective quality assessment (Green for good quality, red for poor quality.)
19
Yes
Unclear
No
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