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................................................................................................................33 Inclusion criteria................................................................................................................4

4 Search Strategy................................................................................................................65 Study selection..................................................................................................................8

6 Data extraction................................................................................................................107 Quality assessment.........................................................................................................11

8 Data synthesis................................................................................................................129 Discussion.......................................................................................................................12

10 Dissemination..............................................................................................................1211 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

5

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

6

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 trackingo Search reference sections of studies identified in the electronic search

o Search reference sections of published guideline documents

► Citation trackingo 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

7

8

► Grey literatureo 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 searchingo Dissertation and Thesis data base search

Proquest

EThOS

Reporting

o Contemporaneous recording of all stages of the process and the results

9

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.

10

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

11

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.

12

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.

13

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 DiscussionThe 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.

14

11 Appendices

15

Appendix ADiagnostic thinking, therapeutic efficacy or patient outcome as defined by Fryback and

Thornbury

Question 1Level 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 2Level 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 3Level 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

16

Appendix B PRISMA flow diagram

17

APPENDIX C – Data extraction form (printed version)

Data Extraction Form v2(Adapted from Albon et al.)

Where the required information is not stated in the study report write NS

Study detailsAuthor; 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 characteristicsPopulation

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 edentulismInclusion/exclusion criteria

Comments:

18

Name of assessor

Evaluator characteristicsNumber of evaluators

Types of evaluator (surgeon, radiologist etc)

Comments:

InterventionsNumber 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:

19

Outcomes for analysis

What were the outcome measures?(complete the sections which apply below)

If outcome measure is simply selection of a different implantIn how many sites was a different implant selected after X sectional or 3D imaging evaluated?

If outcome specifies selection of a different length or widthIn 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 implantIn 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?

20

Appendix D - Quality Assessment Tool (Modified from Quadas 1 by Meads & Davenport)

Author Year

Study title

No. Item N/A Yes Unclear No

1 Was the spectrum of patients representative of patients who will receive imaging in practice?

2 Were the selection criteria clearly described?

4Is 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?

5Did 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.)

6Did the patients receive the same 3D imaging regardless of conventional imaging?

8Was the execution of the conventional imaging described in sufficient detail to permit replication of the test?

9Was the execution of the 3D imaging described in sufficient detail to permit its replication?

10Were the conventional imaging results interpreted without knowledge of the results of the 3D imaging?

11Were the 3D imaging results interpreted without knowledge of the conventional imaging?

12Were 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?

CWas the study and/or collection of clinical variables conducted prospectively?

BWhat was the explanation for patientswho did not receive 3D imaging?(Green for good quality, red for poor quality.)

DWho performed the clinical evaluationand 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 DavenportLetters are additional questions from Meads and Davenport

Overall subjective quality assessment (Green for good quality, red for poor quality.)

21

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