Three-dimensional Mapping of Proximal Caries using Laser Fluorescence

Laser-induced fluorescence can indicate the severity of sub-surface, non-cavitated carious lesions by bacterial by-product (chromophore) fluorescence. Objectives: This in-vitro study developed a methodology to produce three-dimensional mapping of proximal caries and also investigated the efficacy of monitoring in-vitro remineralization using a dynamic in-vitro pH cycling protocol. Methods: Ten recently extracted human teeth stored in distilled water with non-cavitated proximal caries as confirmed visually, radiographically, and by DIAGNOdent readings ranging from 31-99 were selected. An grid pattern in the shape of a rectangle or square encompassing the visible caries was mapped for each specimen utilizing x and y axes allowing fluorescence readings (z axis) in 0.5 mm increments at the cross-sections of the x-y grid pattern for the control group. The specimens were subjected to a dynamic in-vitro pH cycling model for nineteen days. A four-minute application of 2% neutral NaF gel was applied after all remineralization cycles. Laser-induced fluorescence readings (experimental) were obtained on the specimens after the pH cycling. Results: Three-dimensional charts were produced of the control and experimental specimen groups by entering the x, y, & z data into a graphics software program. Independent (paired) Student t-tests (p<0.05) between the cumulative control and experimental laser-induced fluorescence readings resulted in no significant differences in eight out of ten teeth. Conclusions: The results of this laboratory research illustrate that a methodology using laser-induced fluorescence to produce three-dimensional mapping of proximal caries was produced. However, based on the results of the dynamic in-vitro pH cycling with 2% NaF applications, it is suggested that the use of laser-induced fluorescence to monitor remineralization cannot be supported.

Supported by UNMC-COD Student Research Fellowship #FY03-08 and Kavo America Corp.