Characterizing the appearance of ex vivo remineralized white spot lesions with a novel peptide

Abstract

Background: White spot lesions (WSLs) are unfortunate post-orthodontic sequelae that can compromise the final esthetics of treatment, result in caries, and persist indefinitely. Current methods to treat WSLs may promote remineralization, but have not demonstrated consistent improvement with respect to the appearance of the lesion. Purpose: This study explores the remineralizing potential of a novel peptide, amelogenin-derived peptide 5 (ADP5), in comparison with MI Paste Plus (MIPP) and topical fluoride treatment. Methods: Artificial WSLs were created on ex vivo human molars. Teeth were sectioned into samples and randomly assigned to one of four arms: (1) a daily regimen of ADP5 solution, (2) a daily regimen of MIPP, (3) a daily regimen of 20,000 ppm fluoride solution, and (4) incubation in an artificial saliva control. Samples were treated for a period of 2 weeks. Photographs were taken prior to and after treatment. Two panels comprising 5 dental professionals and 5 laypersons assessed before and after pairs of photographs in a blinded fashion. Scanning electron microscopy (SEM) was performed on most samples after treatment to assess the subsurface lesion microstructure and the effects of treatment. Results: After creating WSLs, 11 of these were randomly assigned to the ADP5 group, 12 to the MIPP group, 12 to the fluoride group, and 10 to the control group. The mean improvements assessed by the expert panel were 16%, 16%, 15%, and 8% in the ADP5, MIPP, fluoride solution, and control groups, respectively. The mean improvements assessed by the lay panel were 16%, 13%, 16%, and 8%, respectively. Single factor ANOVA revealed no difference in the amount of improvement across the 4 study groups. SEM images were qualitatively assessed. Samples treated with ADP5 showed an appositional layer of approximately 5 μm and a subsurface remineralization depth of 25 μm. Control samples did not appear to display any apposition or any remineralization. MIPP and fluoride samples were more variable in their presentation, with subsurface remineralization depths ranging from 0 to 25 μm in both groups. Conclusion: Treatment of WSLs with ADP5 did not produce a significantly greater visual improvement when compared to the other treatment groups or the control over the 2-week period. SEM imaging revealed a more consistently achieved remineralization in ADP5 groups compared to MIPP and fluoride groups, as well as a thin appositional layer that was often present.