A comparison of a 2.26% fluoride varnish versus a 1.23% APF foam using polarized light microscopy, confocal microscopy and quantitative light fluorescence

Abstract

Secondary caries and the replacement of existing restorations account for 50 to 70 percent of operative dentistry today. Quantitative Light Fluorescence (QLF) has been shown to be effective at diagnosing very early tooth demineralization on smooth surfaces (less than 50 μ in depth); however, QLF has never been utilized to evaluate secondary caries in dentin. The objective of this study was to validate the accuracy of QLF in diagnosing early secondary caries and then verify the results using confocal microscopy and polarized light microscopy. Seventy-five mandibular molar teeth were prepared with Class V amalgam preparations on the mesial surface. A fluoridated varnish and 1.23- percent acidulated phosphate fluoride (APF) were introduced to this evaluation system, two agents known to effectively inhibit tooth demineralization. The artificial caries system utilized was adjusted to ensure that secondary caries would occur at restoration/tooth surface interfaces. The teeth were exposed to this artificial caries challenge for five days and following lesion formation, QLF was used to determine if incipient demineralization could be detected. The results of the QLF analysis were then compared with the data gathered using confocal microscopy and polarized light microscopy. Our results demonstrate that QLF detected 100 percent of the lesions seen with confocal microscopy and polarized light microscopy; however, no sound specimens were analyzed with any of the three techniques. There were no consistent significant differences between the fluoridated varnish and APF (p < 0.05) with any of the three methods utilized. We conclude that QLF can be used in early caries diagnosis and that emphasis should now be focused on treatment of the early lesion.