Conventional Radiography and Cross Sectional Imaging When Planning Dental Implants In

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 -

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.

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  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  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.

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

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

►  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

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.

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

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.

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.

8  Data synthesis

A narrative synthesis will be carried out under the following headings:

►  Study characteristics

·  Study characteristics will be described by means of narrative and tabulation

►  Core synthesis

·  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.

11  Appendices

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)