title: The influence of zero value subtraction on the performance of a new laser fluorescence device for approximal caries detection.
abstract: The aim of this study was to assess the influence of the zero value subtraction on the performance of laser fluorescence (LFpen) for approximal caries detection. Three areas (cuspal, middle and cervical) of both mesial and distal buccal surfaces of 78 permanent molars were assessed using both wedge-shaped (WDG) and tapered wedge-shaped (TWDG) tips. With the addition of the average, one cut-off value for each area was obtained and the performance was assessed. The areas under the receiver operating characteristics (ROC) curve, specificity, sensitivity and accuracy with and without the zero value subtraction were calculated. The McNemar test revealed a statistically significant difference for specificity at thresholds D(1), D(2) and D(3) (WDG) and D(1) and D(2) (TWDG) when the zero value subtraction was not performed. Influence of the zero value subtraction on the LFpen performance was observed for approximal caries detection. However, when modified cut-off values were used, the zero value subtraction could be eliminated.
authors.affiliation: Department of Preventive Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Freiburgstrasse 7, CH 3010, Bern, Switzerland. jorodrigues@hotmail.com
authors.forename: Jonas Almeida
authors.initials: JA
authors.lastname: Rodrigues
authors.forename: Jonas
authors.initials: J
authors.lastname: de Almeida Rodrigues
authors.forename: Isabel
authors.initials: I
authors.lastname: Hug
authors.forename: Adrian
authors.initials: A
authors.lastname: Lussi
mesh_terms: D003731:Dental Caries / Q000175:diagnosis*; D003762:Dental Instruments; D005453:Fluorescence; D006801:Humans; D066298:In Vitro Techniques; D007834:Lasers; D008963:Molar / Q000473:pathology; D012372:ROC Curve; D012680:Sensitivity and Specificity