Penetration of micro-filled infiltrant resins into artificial caries lesions.

Infiltrants are non-filled low-viscosity resins that have been developed to arrest lesion progression by penetrating into the porosities of non-cavitated lesions where they are hardened and arrest lesion progression. The addition of fillers to infiltrant resin might combine the high penetrativity of the former with the better applicability of composite resins. The aim of the present study was to evaluate the penetration of different experimental micro-filled infiltrant resins (MFIRs) into artificial enamel lesions. An infiltrant (Icon; DMG) was mixed with either one of three fillers [OF83: organic filler (83μm), OF42: organic filler (42μm) or GF0.7: glass filler (0.7μm)] reaching 35, 45 and 55% filler content, respectively. In each of 180 bovine enamel specimens three artificial lesions were created; two lesions were etched for 5s (37% H3PO4), leaving one lesion as control. Specimens were randomly allocated to 10 groups, in which either one of the MFIRs or the infiltrant was applied onto the two etched lesions for either 5s or 10s (n=18/group). Percentage of penetration (PP) was calculated and analysed. For both application times a significant influence of filler size but not of filler concentration on PP could be revealed (p<0.05; two-way ANOVA). PP of MFIRs-OF42 was not significantly different from unfilled infiltrant but significantly higher than those of OF83 and GF0.7 (p<0.05; two-way ANOVA). MFIRs-OF42 showed the ability to penetrate into artificial enamel caries lesions similar to the unfilled infiltrant resin. MFIRs could provide a new micro-invasive treatment for small-cavitated lesions.