A Comparison of MDP and QLF in Early Caries Detection

The detection of early enamel demineralization can result in earlier intervention of the caries process.

Objective: The objective of this in vitro study to assess the use of Micro-Dental-Photography (MDP) for detecting early enamel lesions.

Methods: 80 Extracted human teeth were cleaned, disinfected, and painted with acid resistant varnish leaving a 2x5 mm window of enamel exposed. The teeth were placed in demineralizing medium (acidified gel or Ten Cate acid solution) to form simulated enamel caries lesions. Images of each tooth were captured with MDP and Quantitative Light-induced Fluorescence (QLF). The teeth were thin-sectioned with a hard tissue Microtome and lesion depths measured with Polarizing Light Microscopy.

MDP consists of a high resolution digital camera coupled to a dental operating microscope to capture the tooth image. This image was then analyzed using Image J (NIH) digital analysis software. A QLF image (measures fluorescence, DF), was also analyzed for comparison. Demineralized areas look dark with QLF but white with MDP (measures reflected light, DR).

Results: The lesion depths ranged from 53 to 294µm with the acid solution producing the shallower lesions and the acidified gel the deeper lesions. QLF and MDP were able to detect the presence of lesions almost equally well, r=0.89 p<0.0001 and r=0.80 p<0001 respectively. This study however, observed no statistical significant correlation of lesion depth to DF (r=0.09 with p= 0.41), and only a low correlation suggested with DR (r=0.21 with p=0.06) when both lesion groups were considered. When the two lesion groups were considered separately, correlations showed the differences in outcomes were dependent on lesion type.

Conclusion: MDP was able to detect early enamel caries lesions, but more studies are needed to optimize this technology and determine its usefulness in quantifying lesion progression.