Comparison of Shear Bond Strength of MIM Technology Brackets with Conventional and Rail-Shaped Mesh Bases: An In Vitro Study

The objective of this study was to evaluate in vitro the shear bond strength of two types of MIM (Metal Injection Molding) technology brackets, one with conventional mesh base and the other with rail-shaped mesh base.

Forty human premolars received the bonding of 2 types of brackets: Group 1- 20 Synergy metal brackets (Rocky Mountain) with conventional mesh base and Group 2-20 H4 brackets (OrthoClassic) with rail-shaped mesh base. Both brackets were bonded with Resilience photopolymerizable resin (OrthoTechnology). The specimens were coupled to a Tinius Olsen universal test machine where the shear test was performed using a chisel. In addition, the amount of remaining resin in tooth crown with the ImageJ program was evaluated and the Adhesive Remnant Index (ARI). Intergroup comparison was performed by the independent t test and Chi-square test.

There was no statistically significant difference between the groups for any of the measures evaluated indicating that the mesh type of the brackets’ base with MIM technology did not influence the shear bond strength of the brackets (shear bond strength, p=0.191; maximum load registered, p=0.244). There was also no difference between the percentage (p=0.602) and area of remaining resin in the teeth (p=0.805) and IRA (p=0.625) between the Synergy and H4 groups.

Shear bond strength was similar in the two types of brackets with MIM technology evaluated. In addition, the remaining resin in the dental enamel of two types of brackets were also similar.