RMGI v Composite for Orthodontic Bonding

Overview

Demineralization during orthodontic (brace) treatment is a common clinical problem leading to unsightly white or brown marks on the teeth. A recent systematic review has shown little evidence that current methods of delivering fluoride are effective at reducing this problem. Design: A multi-centre randomised single blinded controlled clinical trial will be conducted with two parallel groups. Setting: The trial patients will be treated by eight named operators on the Specialist List for Orthodontics held by the General Dental Council and who work either within the hospital service or specialist orthodontic practice. The sample size calculation suggests that each operator will need to treat 40 patients in the trial (approx 1 session per week) plus up to 10 familiarisation patients before. Planned trial interventions: Brackets will be bonded to all teeth in front of the first permanent molars with either a resin-modified glass ionomer cement (Fuji Ortho LC) or a light cured composite control (Transbond). The material to be bonded will be allocated randomly. Outcome measures: The two main outcome measures will be the difference in demineralization of the anterior teeth before and after treatment assessed from photographs and the number of debonded brackets during treatment.

Demineralization (dental decay) around fixed appliance components has been reported to occur in up to 95% of cases where brackets are bonded with composite resins. Although early lesions appear clinically as opaque white or brown areas, if mineral loss continues cavitation will occur. Following appliance removal, the lesions may regress or disappear but may still present an aesthetic problem more than 5 years after appliance removal. Fluoride is known to inhibit lesion development and to enhance remineralization following treatment. Resin-modified glass ionomer cements, which release and absorb fluoride, may be used for bracket bonding thereby offering the possibility of less demineralization around bonded attachments. In addition, these cements appear to behave as reliably as composite in terms of bracket failure rate recorded but these data are from case series rather than optimally designed randomised clinical trials. A bonding agent that can behave as reliably as composite and minimize unwanted enamel demineralization would be optimal; saving on restorative costs that may be required should cavitation occur. From the patients perspective, subjective assessment of treatment outcome is likely to be enhanced as ugly demineralised enamel white lesions will be eliminated.