In vitro evaluation of Sensi-IP®: A soluble and mineralizing sensitivity solution

Sensi-IP®OG (SIP-OG) and Sensi-IP®FF (SIP-FF) are soluble bioactive glasses developed to treat dentin hypersensitivity and promote remineralization. Evaluation of their therapeutic potential to reduce dentin hypersensitivity and recover enamel strength was evaluated using standardized in vitro assessments based on simulated use.

To assess dentin occlusion a visual occlusion methodology was employed. Dentin discs were subjected to twice-daily simulated brushing (for 5 days) using 0.67 g of toothpaste for 10 s. Simple prototype toothpastes containing SIP-OG and SIP-FF were compared to commercially available controls: Colgate® Sensitive Pro-Relief (CPR) and Sensodyne® Repair and Protect with NovaMin® (SRP). Samples were stored in artificial saliva between treatments. All samples were assessed at baseline and subsequent to each treatment and were scored on a 5-point categorical scale for occlusion. For enamel surface effects, test articles of SIP-OG, SIP-FF, and SIP-FF with NaF were compared to a positive (with NaF) and a negative (no NaF) control paste. Enamel samples were subjected to a pH cycling regime, providing exposure to the toothpaste slurry (i.e., 2 parts deionized water to 1 part toothpaste), mineralizing solution, and demineralizing solution over 5 days of simulated use. Samples were stored overnight in mineralizing solution. Samples were evaluated for fluoride uptake and changes to surface microhardness.

Visual occlusion scores (1 fully occluded to 5 unoccluded) were 2.6, 3.8, 4.4 and 4.0 after 1 day of simulated use for SIP-OG, SIP-FF with NaF, Colgate® Sensitive Pro-Relief and Sensodyne® Repair and Protect, respectively, decreasing to 1.0, 1.8, 3.1 and 3.9 after 5 days of application. SIP-OG provided superior occlusion at the significance level of p ≤ 0.05 at 1, 2, 3, 4, and 5 days. SIP-FF with NaF provided superior occlusion at the significance level of p ≤ 0.05 at 2, 4, and 5 days. Fluoride uptake ranged from 9.0 μg/cm² for SIP-OG to 12.4 μg/cm² for SIP-FF with NaF. Surface microhardness after acid cycling allowed recovery of 59 % of surface microhardness after treatment with SIP-OG or SIP-FF with NaF. SIP-OG achieved significant surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05. SIP-FF with NaF achieved surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05.

Superior occlusion of dentin tubules was observed with both novel additives compared to commercially available toothpastes. A build-up effect with increasing occlusion was noted with repeated application for both novel additives and ascribed to mineralization effects, as supported by surface microhardness recovery on initial enamel lesions.