A Randomised Controlled Trial to compare preparation of molars for orthodontic bonding using a debonding bur verses no preparation

  • Miesha K Virdi

Student thesis: Doctoral ThesisDoctor of Dental Surgery (DDS)


To determine whether preparing the buccal enamel surface of first molars foruj bonding with a tungsten carbide bur, prior to etching, reduces the bond failure rate of orthodontic molar tubes.

Orthodontic Department at Dorset County Hospital

Bracket failure, which can slow down the progress of fixed appliance treatment, is a common problem during orthodontic treatment. The need to rebond brackets can be costly for both the clinician, in terms of lost clinical time/materials, and the patient/parent due to time lost from school/work. Despite some anecdotal evidence, there is no clinical evidence to support the intervention of using a tungsten carbide debonding bur, in a slow speed handpiece. on the enamel surface of molar teeth prior to etching and bonding, to reduce subsequent bond failures.

A single centre, single blinded, prospective 2-arm, split mouth (Battenberg design), randomised control trial was conducted.

It involved 82 patients, in 2 trial arms A and B, undergoing full upper and lower fixed appliance therapy. In group A, the intervention was used on the buccal enamel of UR6 and LL6 whilst in group B the intervention was used on UL6 and LR6. Bond failures (of all teeth) were recorded over the initial 12-month treatment period. Randomisation ensured equal distribution of types of malocclusion, age and gender to each group.

Bond failure rates relating to the use of the intervention, tooth location, clinical grade and gender were assessed. The data was analysed using mixed effects logistic regression and a marginal predicted mean. The results showed no statistically significant effect of using a debonding bur on the enamel surface of first molar teeth prior to etching and bonding in either analysis (p = 0.110; p=0.121 respectively). Therefore, the primary null hypothesis was accepted. However, overall there were 4.9% fewer debonds following the intervention. This reduction was predominantly seen with maxillary molars.
A statically significant difference was seen between maxillary arch bond failures in comparison with the mandibular arch (with more failures in the mandibular arch) Registrars were also shown to have a statistically significant higher bond failure rate then specialist and consultants. Gender was shown to have no effect on bond failure rates.

Overall, the study showed that use of a tungsten carbide bur on the buccal surface enamel of molar teeth, prior to etching and bonding, does not reduce the subsequent bond failure rate of molar tubes. However, it may have a clinically significant effect in reducing failures in the case of maxillary molars.
Date of Award26 Nov 2020
Original languageEnglish
Awarding Institution
  • University of Bristol
SupervisorTony Ireland (Supervisor), Pamela Ellis (Supervisor) & Martyn Sherriff (Supervisor)

Cite this