Effectiveness of Logicon Caries Detector™ in diagnosis of caries

Objectives: Logicon Caries Detector™ (LCD) is a computer-assisted diagnostic system for caries diagnosis. Gakenheimer et al. (2002) reported its effectiveness in diagnosis but Wenzel et al. (2002) did not. In this study we estimate the effectiveness of LCD in approximal caries diagnosis by inexperienced dentists.

Methods: Fifty extracted teeth with 68 approximal caries were used to assess the diagnostic ability of LCD (LCD Ver 4.0). An RVG 6000 was used as the sensor system. The exposure conditions were 60 kV, 7 mA, and 0.08 sec, and the distance between focus and sensor was 40 cm. This exposure dose was one-quarter of the exposure for the E-speed film. Seven dentists who just passed the Japanese National Dental Board Examination observed the images without LCD (Without LCD) then scored the caries probability using the visual analogue scale (VAS). They also observed the images using LCD and scored the caries probability in a similar manner (With LCD). The results of VAS were analyzed to draw receiver operating characteristic (ROC) curves. Areas calculated under the ROC curves (Az) were statistically tested by the Wilcoxon signed-rank test. Data were analyzed using the Statistical Package for the Social Sciences.

Results: The mean value of the area under the ROC curve (Az) was 0.62±0.06 for Without LCD and 0.66±0.06 for With LCD. The p-value was 0.091 and slightly above the significance level of 0.05. However, 6 out of 7 observers showed better Az values With LCD than Without LCD.

Conclusion: This study showed there was no statistical difference between Without LCD and With LCD in the ability to diagnose caries. However, 6 observers showed improvements in diagnostic ability of With LCD and this probably suggests the validity of LCD. Further experiments using a greater number of observers may be useful.