Influence of chemical conditioning on bonding precoated orthodontic brackets to fluorosed enamel surfaces using self-etch primer

• Published in: Journal of international oral health 2018-09, Vol.10 (5), p.244-249
• Main Authors: Alshahrani, Ibrahim, Abdelaziz, Khalid, Asiry, Moshabab, Alayesh, Afnan
• Format: Article
• Language: English
• Subjects: Acids; Adhesive bonding; Bond strength; Chemical properties; Citric acid; Dental enamel; Enamel; Enamel, Dental; Etching; Failure; Fluorosis; Materials; Materials research; Mechanical properties; Orthodontic appliances; Orthodontics; Phosphoric acid; Premolars; Shear (Mechanics); Statistical analysis; Teeth
• ISSN: 0976-7428; 0976-1799
• DOI: 10.4103/jioh.jioh_190_18

Aim and Objectives: The aim of the study was to evaluate the shear bond strength of precoated orthodontic brackets bonded to chemically conditioned, fluorosed enamel surfaces using self-etch primer. Materials and Methods: Three groups of extracted premolars respectively with no (G1), mild (G2), and moderate (G3) fluorosis were recruited for this study. The buccal surfaces of teeth in each group were conditioned in three subgroups with air-water spray (SG1), 35% phosphoric acid (SG2), and 20% citric acid (SG3) before bonding precoated metal orthodontic brackets by the aid of self-etch primer. The bonded brackets in each subgroup were stressed on a universal testing machine to determine their shear bond strength. The debonded surfaces of each specimen were then assessed to determine the adhesive remnant index (ARI) in each subgroup. The obtained data were analyzed with SPSS software (SPSS version 20.0, SPSS, Chicago, IL, USA). Results: Teeth with mild and moderate fluorosis in G2, G3 provided lower bond strength than normal teeth in G1 (Tukey's, P < 0.05). Enamel surfaces conditioned with phosphoric acid in SG2 offered the highest bond strength in comparison to those conditioned with water and citric acid in SG1 and SG3 (Tukey's, P < 0.05). No statistical difference (Chi-squared, H = 16.48) was detected between the tested subgroups in terms of ARI. Conclusion: The presence of enamel fluorosis adversely affects the shear bond strength of the precoated metal brackets when self-etch primer is considered for bonding. Conditioning the mildly fluorosed enamel surfaces for 60 s with phosphoric acid restores the clinically acceptable brackets bond strength values.