In vivo Effect of Bioactive Glass with Fluoride on Enamel Surface before Orthodontic Brackets Bonding: An Atomic Force Microscopic Analysis

Abstract Background: Enamel demineralization adjacent to orthodontic appliances represents a frequent complication of fixed orthodontic treatment and may adversely affect treatment esthetics. NUPRO ® Extra Care Prophy Paste has been proposed as a preventive agent against enamel demineralization around orthodontic brackets. Therefore, this study aimed to evaluate the in vivo effectiveness of NUPRO ® Extra Care Prophy Paste in reducing enamel demineralization surrounding orthodontic brackets before bonding using atomic force microscopy (AFM). Methods: Twenty orthodontic patients scheduled for the extraction of maxillary first premolars as part of their treatment plan were enrolled. A split-mouth design was employed, whereby the left-side premolars ( n = 20) received conventional fluoride-free prophylaxis paste (control group, Group I), while the right-side premolars ( n = 20) were treated with NUPRO ® Extra Care Prophy Paste (experimental group, Group II). Participants were further allocated into two equal subgroups according to the observation period: Group A (30 days) and Group B (60 days), with n = 10 per subgroup. Following bracket debonding, the teeth were extracted, processed, and examined using AFM to assess enamel surface characteristics. Results: Premolars treated with NUPRO ® Extra Care Prophy Paste demonstrated lower mean surface roughness and smaller surface area (SA) values compared with the corresponding control teeth. Specifically, the experimental group evaluated after 30 days (Group IIA) showed the lowest mean Ra (145.81 ± 43.08 nm) and SA (617.53 ± 31.08 nm 2 ), compared with the control group at the same time point (Group IA: Ra = 250.63 ± 74.91 nm and SA = 675.05 ± 65.48 nm 2 ). The protective effect was most evident after 30 days, whereas the differences between experimental and control groups were reduced after 60 days (Group IIB: Ra = 242.89 ± 59.89 nm and SA = 678.51 ± 38.54 nm 2 ; Group IB: Ra = 324.20 ± 95.12 nm and SA = 736.03 ± 33.26 nm 2 ). Conclusions: A single prebonding application of NUPRO ® Extra Care Prophy Paste was effective in reducing enamel demineralization around orthodontic brackets for up to 1 month; however, its protective effect was not maintained over a 2-month period.