Orthodontic Sealants in Preventing Enamel Demineralization: An in-vitro Study

Objectives: To determine the efficacy of two orthodontic sealants products: Opal Seal (OS)(Opal Orthodontics,Ultradent, South Jordan, UT), a 38% glass ionomer and nanofilled resin-based sealant, and Pro Seal (PS)(Reliance Orthodontic Products, Itasca, IL), a 17% filled resin-based sealant; in prevention of enamel demineralization using confocal microscopy. To determine also the lengths of brushing and time of pH cycling on the protectability of the materials. Methods: A total of 27 permanent molars were sectioned in halves, sterilized and mounted in orthodontic resin. They were randomly divided into three groups: surface applied sealants with PS, OS or Controls (no surface treatment). Each group was further divided into six subgroups (n=3) for brushing time (0, 2 or 4 hrs) with a mechanical toothbrushing machine and pH cycling treatments with demineralization and remineralization solutions (24 or 48 hrs). Lesion depth, lesion area, and the thickness of remaining sealant were measured using confocal microscopy. The lesion depth and area were analyzed using ANOVA and Tukey-Kramer test for sealant type, brushing time, pH cycling period and their interactions, with significant level set at p≤0.05 .  Results: The application of sealant and the  pH cycling  significantly affected the  lesion depth and lesion area (p<0.0001). No significant differences were found in lesion depth and lesion area between the sealant groups: OS (19.03±13.58µm;  15018.4±10375.36µm²) and PS (20.14.0±12.46µm; 14455.5±9339.36µm²) but was significantly different than the control group with no surface treatment (40.11±16.77µm; 35169.2±10816.08µm²)  (p<0.0001). Thickness of remaining sealant diminished with time of brushing but no significant differences were found between the two sealant products (p=0.22).  Conclusions:  Application of  either sealant provides equivalent protection to the tooth surface exposed to demineralization in-vitro.