Comparison of bond strength in fixed multistrand retainers using universal and conventional adhesives: An in vitro study

To prevent relapses, fixed retainers are used. However, bond failure is a common issue. This study compares shear bond strength and failure mode using conventional and universal adhesives (UAs), containing 10-MDP, with different application methods.

In this in vitro study, 120 intact maxillary premolars were divided into four groups and treated with a UA or a conventional adhesive (CA) with or without a primer application on wire. The teeth were assessed using a 0.0195" three-strand multistrand wire and a high-filler flowable composite. Bond strength was measured after thermocycling, and the adhesive remnant index (ARI) was determined for all samples. An independent t-test was used to compare the means of quantitative variables, and a Chi-square test was used to compare the distribution of qualitative data (P < 0.05).

The mean bond strength for the group where the primer was applied to the wire surface with UA was 33.28 Newton (N), and with CA, it was 37.17 N. The mean bond strength of the samples without primer application on the wire surface with UA and CA was 40.88 N and 38.42 N, respectively, despite no statistically significant differences between the groups (P > 0.05). There was no significant difference in ARI between the groups with and without primer application on the wire surface.

The application or nonapplication of primer on the wire surface and the type of adhesive had no significant effect on the bond strength and ARI of the samples.