Effects of procedures of remineralization around orthodontics bracket bonded by self-etching primer on its shear bond...

To evaluate the effect of the application of either fluoride varnish (FV) or amorphous calcium phosphate (ACP) as preventive method on shear bond strength (SBS) at the same time of their bonding in vitro using self-etching primer (SEP) as an agent for enamel pre-treatment FV.

SIXTY HUMAN BICUSPIDS WERE RANDOMLY DIVIDED INTO FIVE GROUPS: G1 was rubbed by SEP for 5 s, G2 for 5 s by SEP and ACP, G3 for 10 s by SEP and ACP, G4 for 5 s by SEP and FV, and G5 for 10 s by SEP and FV. Stainless steel metal brackets were bonded. A Zwick/Roell Z020 Universal Testing Machine (Zwick GmbH and Co, Germany) with a 500 N load cell was used to test SBS. SBS values were analyzed using one-way analysis of variance (ANOVA) and Tukey's post hoc tests (P≤0.05). Differences in adhesive remnant index (ARI) values between groups were calculated.

The mean SBS values were 10.00±4.48 MPa, 5.71±4.3 MPa, 7.47±4.44 MPa, 4.4±2.39 MPa, and 3.98±0.83 MPa for groups 1-5, respectively. Significant differences in SBS values between all groups were found. The mean SBS values of groups 2, 4, and 5 were significantly lower than that of the G1. No significant difference was found between G3 and G1. Significant difference in ARI between the groups was found (P<0.001) and G1 had a significantly higher ARI.

The results suggested that the application of ACP at the same time of using SEP for 10 s has no effect on SBS.