Sidi 1988.

Study characteristics
Patient Sampling	Method of sampling: selected ‐ participants taking part in a caries trial Included conditions: only surfaces considered to be sound by clinical evaluation were evaluated with the transillumination device Teeth: permanent molar and premolars Sealants: not reported Restorations: not reported Surface: approximal
Patient characteristics and setting	Age: 21 to 64 years (mean 28 years) Sex: not reported Ethnicity: not reported Country: not reported Setting: clinical trial; "carried out away from the dental surgery" Number of participants/teeth/sites: 456 participants, 4405 surfaces (71 participants could not be radiographed within the study) Prevalence: enamel 0.03, dentine 0.01 (very low prevalence results in high concern for applicability)
Index tests	Category of test: FOTI Sequence of test(s): visual examination preceded radiographs and transillumination, radiographs developed and interpreted at a later date Examiner training and calibration: not reported Threshold applied: sound, enamel, dentine Device specifics: liquid light transmission cord: Kulzer and Co, placed buccally and lingually
Target condition and reference standard(s)	Category: radiographs Sequence of index test and reference standard: reference standard completed prior to transillumination Training of examiner: not reported Blinding to index test: yes ‐ attempt made to blind examiners to index test results Multiple tests: visual completed but without separation so not a viable reference standard Site selection: all surfaces Target condition: sound, enamel, or dentine
Flow and timing	Participants with index test but no reference standard: all participants that received radiographs also were examined with transillumination ‐ 71 participants did not receive radiographs, unclear on the number that received a clinical examination but did not receive transillumination test Participants with reference standard but no index test: 0 Time interval between tests: unclear Participants receiving both tests but excluded from results: 0
Comparative
Notes	Buccal and lingual results totaled for our data analysis, from table IV
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Unclear
Could the selection of patients have introduced bias?		High risk
Are there concerns that the included patients and setting do not match the review question?			High
DOMAIN 2: Index Test (All tests)
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Yes
If multiple tests were applied were different examiners used for each (in vivo)?	Unclear
Could the conduct or interpretation of the index test have introduced bias?		Unclear risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	No
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		High risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			High
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	Unclear
Were all patients included in the analysis?	Unclear
Could the patient flow have introduced bias?		Unclear risk