Nakagawa 2013.

Study characteristics
Patient Sampling	Method of sampling: "arbitrarily chosen for investigation" Included conditions: no cavitation and early lesions; "visible localized enamel surface discoloration (white, brown/black) or cavitated carious lesions involving an axial smooth enamel surface", therefore an attempt to have no sound surfaces Teeth: not reported Sealants: not reported Restorations: not reported Surface: smooth
Patient characteristics and setting	Age: not reported Sex: not reported Ethnicity: not reported Country: Japan Setting: extracted teeth Number of participants/teeth/sites: 93 teeth, 127 sites Prevalence: enamel 0.75, dentine 0.31
Index tests	Category of test: SS‐OCT Sequence of test(s): index tests performed (visual, SS‐OCT) prior to reference standard; "Visual examination and SS‐OCT evaluations were performed in separate sessions and after shuffling the order of appearance for each case to ensure there was no interference from the previous observations" Examiner training and calibration: 4 dentists, 2 with 9 years experience trained the other 2, with calibration Threshold applied: sound, enamel demineralisation without surface breakdown, enamel breakdown due to caries, dentine caries Device specifics: SS‐OCT (OCT‐2000, Santec, Komaki, Japan); "The lateral resolution of 17 mm is determined by the objective lens of the probe. A 2000 1024 pixel image is obtained in the real‐time and processed in a few hundred milliseconds"
Target condition and reference standard(s)	Category: histology Sequence of index test and reference standard: index test then reference standard Training of examiner: "Two examiners with sufficient experience in histopathological study of caries" Blinding to index test: unclear Multiple tests: no Site selection: sectioned teeth, through locations used for index test Target condition: sound, superficial enamel demineralisation, enamel breakdown, dentine caries
Flow and timing	Participants with index test but no reference standard: 0 Participants with reference standard but no index test: 0 Time interval between tests: minimal Participants receiving both tests but excluded from results: 0
Comparative
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	No
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)?	No
Could the conduct or interpretation of the index test have introduced bias?		Low 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?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
Could the reference standard, its conduct, or its interpretation have introduced bias?		Low risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Low concern
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?	Yes
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Low risk