Assessment of dimensional accuracy of Preadjusted Metal Injection Molding (MIM) orthodontic brackets

Shiva Alavi, Farnaz Tajmirriahi



Background: the aim of this study is to evaluate the dimensional accuracy of MBT (McLaughlin, Bennett and Trevisi ) brackets manufactured by two different companies (American orthodontics and Ortho organizers) and determine variations in incorporation of values in relation to tip and torque in these products.

Methods: In the present analytical/descriptive study, sixty-four maxillary right central brackets manufactured by two companies (American Orthodontics and Ortho Organizers) were selected randomly and evaluated for the accuracy of the values in relation to torque and angulation presented by the manufacturers. They were placed in a video measuring machine using special revolvers under them and were positioned in a manner so that the light beams would be directed on the floor of the slot without the slot walls being seen. Then the software program of the same machine was used to determine the values of each bracket type. The means of measurements were determined for each sample and were analyzed with independent t-test and One-sample t-test.

Results:Based on the confidence interval it can be concluded that at 95% probability the means of tip angles of maxillary right central brackets of these two brands were 4.1‒4.3° and the torque angles were 16.39‒16.72°. The tips in these samples were at a range of 3.33‒4.98° and the torque was at a range of 15.22‒18.48°.


 In the present study, there were no significant differences in the angulation incorporated into the brackets from the two companies; however, they were significantly different from the tip values for the MBT prescription. In relation to torque, there was a significant difference between the American Orthodontic brackets exhibited significant differences with the reported 17°, too.

Keywords: Orthodontic, appliance, prescription

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