Effect of the calibration method of a laser fluorescence device for detecting occlusal caries in primary molars

The purpose of this study was to verify the influence of individual calibration on sound tooth surfaces and the number of readings on in vitro performance of a laser fluorescence (LF) device to detect occlusal caries in primary teeth.

After standard calibration (on the porcelain reference object), 72 clinically suspect sites on occlusal surfaces of 54 exfoliated or extracted (for orthodontic purposes) primary molars were assessed using the DIAGNOdent. First, after individual calibration (on a sound surface of each tooth), 3 readings were performed for each site. Subsequently, another 3 readings were taken, but without individual calibration on a sound surface of the tooth. After these assessments, sites were also evaluated with only one reading after individual calibration. Histological validation was performed as the gold standard. LF values, sensitivity, specificity, accuracy (number of correct diagnosis in both sound and diseased teeth) were calculated and compared using the McNemar change test. The area under receiver operating characteristics (ROC) curves was also compared.

Readings with standard calibration only (mean= 11.7 +/- 10.6 SD) were significantly higher statistically than assessment with 3 readings after individual calibration (10.7 +/- 10.7) and with 1 reading (10.2 +/- 8.3) after individual calibration. Nevertheless, sensitivity, specificity, accuracy, and area under ROC curve did not change significantly.

Absence of individual calibration does not affect the laser fluorescence device's performance in detecting occlusal caries in primary teeth.