Aluminum oxide orthodontic brackets :
Date
2004
DOI
Authors
Rizkallah, Mouhab Zakhari
Version
OA Version
Citation
Abstract
It has been postulated that ceramic orthodontic brackets having smaller particle size and smoother surface characteristics will have greater fracture strength. The purpose of this study was to compare four popular, polycrystalline ceramic brackets on the basis of torque fracture strength. Additionally, this study attempted to improve the surface smoothness of two of the tested groups via surface glazing. Moreover, this study was designed to determine if the smoothness as well as strength claims made by some ceramic bracket manufacturers can be validated and legitimized.
One hundred fifty-four 0.022 x 0.028” slot maxillary left central incisor ceramic brackets, constituting four brand name brackets (T, S, Mq, Mx) were obtained. T & S represented conventional milled slot brackets; Mq represented milled and manufacturer glazed brackets; Mx represented injection molded brackets. Sample sizes for each group were T=58, S=50, Mq=21, Mx=25. Groups T & S were both roughly evenly subdivided into control samples (T [subscript c] & S [subscript c]) and test samples (T [subscript g] & S [subscript g]). Control samples were tested in the as received condition, while test samples were glazed & baked prior to fracture testing in an attempt to improve the fracture strength of the brackets. The resulting six test groups (T [subscript c], T [subscript G], S [subscript c], S [subscript G], Mq, Mx) were then evaluated for fracture strength using a specially designed torquing apparatus attached to an Instron machine. The Instron machine applied and recorded palatal root torsional forces to each bracket tested. Load (N) at failure was recorded.
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Description
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Thesis (MSD)--Boston University, Henry M. Goldman School of Dental Medicine, 2004 (Orthodontics).
Includes bibliographical references: leaves 83-88.
Thesis (MSD)--Boston University, Henry M. Goldman School of Dental Medicine, 2004 (Orthodontics).
Includes bibliographical references: leaves 83-88.
License
This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.