Efficacy of Three Enamel Protecting Agents on Shear Bond Strength of Orthodontic Brackets Bonded to Demineralised Enamel with Conventional Adhesive

Abstract

Introduction: Enamel demineralisation is common in the patients undergoing orthodontic treatment with fixed appliance and bonding of the orthodontic brackets on demineralised enamel surfaces compromises clinical outcome. Aim: To compare the effect of flouride varnish, Casein Phosphopeptide-Amorphous Calcium Phosphate Fluoride (CPP-ACPF) and resin infiltrant on Shear Bond Strength (SBS) of adhesives used to bond orthodontic brackets on demineralised enamel. Materials and Methods: This comparative in-vitro study was conducted in the Faculty of Dentistry, MAHSA University, Kuala Lumpur, Selangor, Malaysia, from September 2017 to March 2018. A total of 60 premolars were exposed to three cycles of demineralisation-remineralisation for 18 days and were grouped equally into four groups. Group I was without any enamel pretreatment while group II was treated with Fluoride varnish (Duraphat), group III with CPP-ACPF (GC Tooth Mousse Plus) and group IV with resin infiltrant (Icon). The orthodontic brackets were bonded to buccal surface of premolars with Transbond XT, conventional orthodontic light cure adhesive system and SBS (MPa) was measured following mechanical shearing of bracket under universal testing machine. Statistical comparisons were done using Welch Analysis of Variance (ANOVA) and Games Howell Post-hoc Test. Results: The highest SBS values were found in group IV (16±5.2 MPa) followed by group I (13.5±6.6 MPa), group III (9.8±2.8 MPa) and group II (3.4±2.7 MPa). Pairwise comparison of SBS scores between following groups were found statistically significant i.e., Group I and group II (p-value< 0.001), group II and group III (p-value< 0.001), group II and group IV (p-value< 0.001), and between group III and group IV (p-value= 0.004). The SBS scores between group I and group III (p-value=0.212) and between group I and group IV (p-value=0.671) were not significantly different from each other. Conclusion: Demineralised enamel pretreated with resin infiltrant (Icon) showed highest SBS among all the groups while fluoride varnish application showed lowest SBS. To prevent remineralisation during orthodontic treatment, Icon can be used as prophylaxis agent before brackets are bonded to teeth with enamel lesion.

Keywords

• fluoride varnish
• gc tooth mousse
• remineralisation
• resin infiltrant
• universal testing machine
• white spot lesion