Experimental laser fluorescence characteristics of initial caries lesions after resin infiltrant application

Initial caries lesions (ICLs) are most commonly treated using remineralization procedures with fluoride, alongside recommended improvements in oral hygiene. An alternative approach is the micro-invasive method of infiltration using low-viscosity light-curing resin (RI). The aim of this study was to evaluate the influence of low-viscosity resin infiltration of natural, proximal initial carious lesions on changes in fluorescence under in vitro conditions.

The material consisted of n = 49 human permanent maxillary and mandibular premolars, extracted for orthodontic reasons, presenting ICLs of ICDAS code 1 and 2 on the approximal surface, with fluorescence values not exceeding 30. Each lesion was examined using a DIAGNOdent pen laser device (LFpen). Subsequently, the ICLs underwent low-viscosity resin infiltration (Icon Smooth Surface, DMG, Germany), and fluorescence measurements were carried out again.

Fluorescence values (mean ± SD) after infiltration amounted to 7.8 ± 4.6 and were significantly lower than before (13.8 ± 5.2) the procedure (Wilcoxon Signed-Rank test; p < 0.001). Additionally, there was statistically significant positive correlation between the fluorescence measurement values before and after RI, higher pre-infiltration results corresponded to higher post-infiltration results (Spearman correlation coefficient p < 0.001).

Under in vitro conditions, application of resin infiltrant resulted in decreased fluorescence of ICLs what can support no lesion progression in clinical conditions.

Resin infiltration of initial caries lesions significantly reduces laser fluorescence values, indicating changes in lesion composition and optical properties. These findings support the use of infiltration as a minimally invasive treatment and suggest laser fluorescence may aid in monitoring post-treatment lesion behavior under clinical conditions.