Fissure caries is a problem to diagnose and treat.

Ozone (O3) has been proven to clinically reverse root caries and affect its quantitative light-induced fluorescence (QLF) readings. O3 is proposed as a novel pharmaceutical approach to manage fissure caries.

Objectives: to correlate QLF readings with a clinical and histological classification of fissure caries, and then to study the effect of Ozone application on these readings.

Methods: A total of 200 QLF (DIAGNOdent®, KaVo Germany) readings were recorded on extracted teeth and correlated with a clinical and histological classification of fissure caries (Ekstrand, 1998). The readings were repeated after cleaning the occlusal fissures of the teeth with the Prophyflex 2® (KaVo Germany) air-powder abrasive prophylaxis system. Another 42 readings were recorded on freshly extracted teeth before, after using the cleaning system, after O3> application using a sealed cup via a hand piece (HealOzone unit, CurOzone USA) for 10s and then after another sequential O3 10s application.

Results: QLF readings correlated significantly with the clinical classification (rs = 0.72, p < 0.01) and both correlated with the histological classification (rs = 0.61 and 0.624, p < 0.01 respectively). The cleaning system increased the QLF readings correlation with the clinical and histological classifications (rs = 0.79 and 0.70, p < 0.01 respectively) and improved the correlation of the clinical classification with the histological classification(rs = 0.67, p < 0.01). O3 application further reduced the readings significantly ((10s) p < 0.047, and (20s) p < 0.002).

Conclusion: The application of ozone has an immediate effect by reducing QLF readings and this reduction increases with doubling the application time. Cleaning the teeth using a cleaning system improved the yield of clinical diagnosis and QLF readings. The clinical classification can be used as a valid diagnostic measure.