Penetration of Micro-Filled Infiltrant Resins into Artificial Caries Lesions

Infiltrants are non-filled low-viscosity resins that have been developed to penetrate into caries lesions where they are hardened and arrest lesion progression. The addition of fillers might improve the rheological and mechanical properties, thus extending the indication spectrum to occlusal and smooth surface enamel cavities. The aim of the present study was to evaluate the penetration of experimental micro-filled infiltrant resins (MFIR) into artificial enamel lesions.

Methods:

An infiltrant (Icon; DMG) was mixed with either one of three filler powders (MFIR A: organic fillers size 20-200µm, mean 83 µm, MFIR B: organic fillers size 0.5-200µm, mean 42µm or MFIR C: Barium glass fillers 0.7µm) reaching 35%, 45% and 55% filler content, respectively. In each of 180 bovine enamel specimens three artificial lesions were created using a demineralizing solution for 200 days. In each specimen two lesions were etched for 5s (37% H₃PO₄), leaving one lesion as untreated control. Specimens were randomly allocated to 10 groups in which either one of the experimental resins or the unfilled infiltrant (control) was applied onto the two etched lesions for either 5s or 10s (n=18/group). Specimens were analyzed with CLSM and penetration depths (PD) and lesion depths (LD) were measured. Percentage penetration was calculated (PP=PD×100/LD) and analyzed statistically.

Results:

For 10s application time, variance analysis revealed a significant influence of filler type but not of filler concentration on PP (p<0.05; ANOVA, Bonferroni). PP [mean(SD)] of unfilled infiltrant [88(7)%] was not significantly higher than MFIR B [81(7)%] but significantly higher than MFIR A [74(10)%] and MFIR C [71(11)%] (p<0.05; Bonferroni).

Conclusion:

MFIR B showed the ability to penetrate into artificial enamel caries lesions similar to the unfilled infiltrant resin.