Dental Demineralization around Orthodontics Brackets and Shear Bond Strength

Methods: Sixty freshly extracted human bicuspid were collected and divided to five groups: G1 were rubbed for 5 sec. by SEP (control group), G 2- 5 sec. SEP and ACP (Tooth mousse-GC), G 3- 10 sec. by SEP and (Tooth mousse-GC), G 4- 5 sec. by SEP and DuraSheield 5% Sodium fluoride varnish, G5- 10 sec. SEP and DuraSheield 5% Sodium fluoride varnish. Stainless steel metal brackets bonded to the teeth by using light curing composite. Zwick Roell machine was used to test SBS. SBS were calculated and analyzed using One-Way ANOVA test analysis of variance (p≤0.05), and Multiple comparisons Tukey HSDtest. Differences in ARI values between groups by a Kruskal-Wallis test was calculated and the Mann-Whitney U.

Results: The mean (SBS) were 10.00± 4.48 MPa (G1) 5.71 ±4.3 MPa7 (G2), 7.47± 4.44 MPa (G3), 4.4 ±2.39 MPa (G4) and 3.98± 0.83 MPa (G5). one-way analysis of variance verified significant differences in SBS (F=5.61,p=0.001) and Multiple comparison (Tukey HSD test) showed that mean SBS of 2, 4 and 5 were significantly lower than mean SBS of control group and mean SBS of group3 (calcium phosphate 10 Sec SEP) was no significant difference.

A Kruskal-Wallis test showed a significant difference in ARI existed between the groups (P = .000). A Mann-Whitney showed that the Group 1 was found to have a significantly higher ARI score than all groups. Pearson correlation coefficients (0.543) showed strong correlation between SBS and ARI score (P=.000).

Conclusion: The results suggested the application calcium phosphateas preventive materials of enamel demineralization at same time the using SEP for 10 Sec. may have a clinical application and doesn't affects on shear bond strength.