Lederer 2018.

Study characteristics
Patient Sampling	Method of sampling: selected Included conditions: sound or early enamel lesions; "either an intact, sound interproximal surface or non‐cavitated proximal caries lesions" Teeth: permanent Sealants: not reported Restorations: excluded Surface: approximal
Patient characteristics and setting	Age: not reported Sex: not reported Ethnicity: not reported Country: Germany Setting: extracted teeth Number of participants/teeth/sites: 53 teeth, 106 teeth Prevalence: enamel 0.36, dentine 0.16
Index tests	Category of test: 2 tests: NIR light ‐ DIAGNOcam, also near‐infrared light combined with high‐dynamic‐range imaging (NIR‐HDRI) Sequence of test(s): NIR and NIR‐HDRI, prior to reference standard Examiner training and calibration: "2 experienced examiners ..... were given a practical and theoretical training session", examiner assessments completed independently and repeated after 2 weeks Threshold applied: no decay, enamel, enamel with single point of contact to dentino‐enamel junction, enamel with extensive contact to dentino‐enamel junction, dentine Device specifics: DIAGNOcam ‐ "Instead of the clinical tip of the DC, the laser optical unit of the in vitro model was used for transillumination to obtain comparable images. The DC could be pivoted over the tooth, and images obtained with the KaVo KiD (KaVo integrated Desktop) software" NIR‐HDRI ‐ "Images were obtained with an above‐mounted NIR camera manufactured by IDS (UI‐1241LE‐NIR‐GL, Imaging Development Systems GmbH) together with a Tamron 50‐mm lens" Note ‐ applicability is "high concern" as techniques used in paper are specifically designed scenarios established in an in vitro setting which are not currently available for a clinical setting
Target condition and reference standard(s)	Category: microCT Sequence of index test and reference standard: reference standard followed index test assessments Training of examiner: unclear; "Measurements were taken 3 times by one examiner, and the mean values calculated" Blinding to index test: unclear Multiple tests: no Site selection: extracted tooth microCT scan Target condition: radiolucency in the outer, or the inner half of the enamel, and radiolucency in the dentine
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?	No
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Yes
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?		Unclear risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			High
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?		Unclear 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