Occlusal caries detection: a comparison of a laser fluorescence system and conventional methods

The purpose of this study was to compare the effectiveness of a laser fluorescence (LF) device (DIAGNOdent) with a visual and radiographic scoring system for in vitro detection of occlusal caries and to evaluate the effect of 1% NaOCl immersion on the LF readings.

A total of 54 extracted third molars with macroscopically intact occlusal surfaces were selected. Three examiners assessed 105 sites by visual inspection (VI), bitewing radiography (BWR), and LF. Ten days after the first measurement, all teeth were reevaluated using the same methods. Then, teeth were immersed in 1% NaOCl solution for 24 hours, and LF readings were taken again. Caries extension was assessed by histology (x40). The diagnosis methods were compared by means of sensitivity, specificity, intra- and interexaminer reproducibility, and area under receiver operating characteristic (ROC) curve. The mean values of the first, second, and third LF readings from the 3 examiners were compared by one-way analysis of variance and Student-Newman-Keuls test.

No difference was found among the areas under ROC curve. Regarding sensitivity, however, both VI and LF performed similarly (P>.05) and superiorly to BWR (P<.05). All methods showed a similar performance regarding specificity. The intra- and interexaminer reproducibility was good for all methods. A significant reduction of the LF reading was found after immersion in 1% of NaOCl.

It was concluded that visual inspection is as valid an evaluation method as the laser fluorescence device, which should be considered a better adjunct for occlusal caries diagnosis than BWR.