Slot, Tip, and Torque Deviations in Commercial MBT Metal Brackets

Abstract

AIM: To quantify deviations in slot size, tip and torque values of commercially available MBT-prescription metal brackets relative to MBT standard.

METHODS: A literature review was performed. Electronic searches were conducted between march and may 2023 via PubMed, ResearchGate and Google Scholar. A total of 16,223 records were retrieved; 58 articles were assessed by full-text screening and 20 studies were included according to predefined inclusion and exclusion criteria.

RESULTS: The ideal tip value is 4 degrees; observed tip values ranged from 1.67 to 6 degrees. The ideal torque value is 17 degrees; observed torque values ranged from 7.67 to 17.81 degrees. Measured slot heights ranged from a minimum of 0.0209 inch at the base to a maximum of 0.0261 inch at the face, whereas the bracket claimed a 0.022 inch slot heights ranged from.

CONCLUSION: A substantial proportion of measured brackets exhibit dimensional deviations from stated values. International standards for acceptable manufacturing tolerances and mandatory pre-market quality assessment are recommended. A consistent, repeatable measurement protocol should be established to reduce placement-related measurement error and to improve comparability across studies.