Masking of white spot lesions by resin infiltration in vitro

Abstract

Objectives: The aim of this in vitro study was to evaluate the ability of one commercial and five experimental infiltrating resins (infiltrants) to camouflage enamel white spot lesions immediately after resin infiltration and after a staining period.

Methods: In each of 120 bovine enamel samples, two artificial caries lesions were created (windows A and C; pH=4.95, 50 days), whereas two windows were protected serving as sound controls (B and D). After etching windows C and D (37% phosphoric acid), specimens were randomly allocated to 6 groups. Either one of 5 experimental infiltrants or a commercial infiltrant (Icon, DMG) (refractive indices 1.50-1.55) was applied and light cured. After half of each specimen was polished, samples were remineralized (pH=7.0) and stained with tea and red wine for 50 days. Photographic images after various treatment steps were obtained. Color differences (ΔE) of untreated (A) and treated lesions (C) as well as infiltrated sound enamel (D) were compared with untreated enamel (B).

Results: All infiltrants showed significantly better color match with sound enamel (median ΔE [25th/75th percentile]: 2.2 [1.5/3.1]) than untreated controls (9.3 [8.0/10.9]) (p<0.001, Wilcoxon, post hoc Bonferroni). Moderate correlation between refractive index and ΔE of infiltrated lesions was demonstrated (R(2)=0.43, p>0.05). Staining was significantly reduced for polished infiltrated lesions compared to untreated or infiltrated unpolished lesions (p<0.001).

Conclusions: Resin infiltration is suitable to mask artificial white spot lesions. Polished infiltrated lesions are resistant to staining in vitro.

Clinical significance: Resin infiltration is a micro-invasive approach to camouflage post-orthodontic white spot lesions.

Keywords: Aesthetics; Caries infiltration; Color; Infiltrant; Refractive index; White spot lesions.