title: A pilot study for evaluation of bond strength of orthodontic brackets to enamel using a new impact test machine.
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.
authors: University of Edinburgh, Postgraduate Dental Institute, Edinburgh, UK.
authors: R E
authors: RE
authors: Hendry
authors: T
authors: T
authors: Gilgrass
authors: L
authors: L
authors: Chung
authors: R
authors: R
authors: MacPherson
authors: T H J
authors: TH
authors: Yang
authors: R L
authors: RL
authors: Reuben
mesh_terms: D000269:Adhesives; D001840:Dental Bonding / Q000295:instrumentation*; D003743:Dental Enamel; D003817:Dentition; D006801:Humans; D016382:Orthodontic Appliance Design / Q000295:instrumentation*; D016910:Orthodontic Brackets; D009970:Orthodontics / Q000295:instrumentation; D010865:Pilot Projects; D014082:Tooth Fractures
chemical_list: D000269:Adhesives