Affiliations: [a] Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, Saudi Arabia. E-mails: drdurgesh19@gmail.com, smalhijji@ksu.edu.sa, omer_hh@yahoo.com, aalkhuraif@ksu.edu.sa | [b] Department of Biomaterials Science, Institute of Dentistry, University of Turku, Turku, Finland | [c] Dental Biomaterials Department, College of Dentistry, Al Azhar University, Egypt | [d] General Dentist, Private Dental Practice, Riyadh, Kingdom of Saudi Arabia. E-mail: pavithradr1983@gmail.com | [e] Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Saudi Arabia. E-mail: malsharawy@ksu.edu.sa | [f] Department of Biomaterials Science, Institute of Dentistry, University of Turku and City of Turku Welfare Division, Finland. E-mail: pekval@utu.fi | [g] Visiting Professor Program, King Saud University, Saudi Arabia
Correspondence:
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Corresponding author: Dr. Bangalore H. Durgesh Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia. Tel.: +966537135611; E-mail: drdurgesh19@gmail.com.
Abstract: Background:Adhesive resin composite, which is used to bond orthodontic bracket to tooth surface is exposed to the influence of wear by tooth brushing and wear may influence loosening of the bracket. Objective:The aim of this study was to evaluate in vitro the effect of tooth brushing on the adhesion strength of orthodontic brackets bonded to surface treated porcelain. Method:A total of 90 glazed porcelain fused to metal facets (PFM) were randomly assigned into 3 groups according to the surface treatment to be received. Group 1 was conditioned with hydrofluoric acid (HF), group 2 conditioned with grit-blasting (GB) and group 3 conditioned with tribochemical silica coating (RC). The groups were evaluated for surface roughness (Ra) before and after surface treatment. Next, 15 samples from each group were subjected to brushing and remaining 15 samples served as the baseline (n=15). Adhesion strength (shear bond strength)was recorded using a universal testing machine. Data collected were analyzed by ANOVA and Tukey’s multiple comparison post hoc analysis. Results:Tooth brushing decreased the bond strength in all groups. The highest adhesion strength (baseline and after brushing) was observed in group 3 (26.8 ± 1.77 MPa and 23.57 ± 1.02 MPa) and the lowest was found in group 1 (9.6 ± 1.5 MPa and 5.87 ± 0.77 MPa). Group 3 specimens exhibited the highest Ra (1.24 ± 0.08). Conclusion:It was found that tooth brushing of the exposed adhesive resin composite at the bracket-bonding substrate interface lowers the bonding strength regardless of the surface treatment of the substrate.
