A pilot study for evaluation of bond strength of orthodontic brackets to enamel using a new impact test machine

R. E. Hendry, T. Gilgrass, L. Chung, R. MacPherson, T. H. J. Yang, R. L. Reuben

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We report an in-vitro pilot study to assess the ability of a new impact test machine to evaluate bond strength of orthodontic brackets to tooth enamel. A total of 37 extracted premolar teeth were bonded with APC Plus MBT Victory orthodontic brackets. Bond strength was tested using a new pendulum-based instrumented impact test machine. The maximum stress, the impact energy and interaction time required to debond the brackets were recorded. Of the total tested, 9 samples were successfully debonded with no obvious damage to the tooth surface although 28 samples fractured through the enamel and dentine. There was a statistically significant difference between the maximum stress required to debond the bracket and that required to fracture the tooth, a higher stress being required to debond the bracket. Significantly less stress was required to fracture older teeth. The high incidence of tooth fracture suggests a need to modify the impact test protocol. The lack of a simulated periodontal ligament, which is present clinically and acts as a shock absorber, may have contributed to the high failure rate, although the striking position of the pendulum also needs to be considered.

Original languageEnglish
Title of host publicationMedicine meets engineering
EditorsJ Hammer, M Nerlich, S Dendorfer
Place of PublicationNetherlands
PublisherIOS Press
Number of pages9
ISBN (Print)9781586038281
Publication statusPublished - Mar 2008
Event2nd Conference on Applied Biomechanics - Regensburg, Germany
Duration: 13 Jun 200715 Jun 2007

Publication series

NameStudies in Health Technology and Informatics
ISSN (Print)0926-9630


Conference2nd Conference on Applied Biomechanics


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