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

Stud Health Technol Inform. 2008:133:103-11.

Abstract

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.

MeSH terms

  • Adhesives*
  • Dental Bonding / instrumentation*
  • Dental Enamel*
  • Dentition
  • Humans
  • Orthodontic Appliance Design / instrumentation*
  • Orthodontic Brackets*
  • Orthodontics / instrumentation
  • Pilot Projects
  • Tooth Fractures

Substances

  • Adhesives