Retention of orthodontic brackets bonded with resin-modified GIC versus composite resin adhesives--a quantitative systematic review of clinical trials.

The aim of this systematic review was to establish whether the clinical debonding (failure) rates of orthodontic brackets bonded either with resin-modified glass ionomer (RM-GIC) or with composite resin adhesive are the same. Five databases were searched for articles up to 18 November 2010. Inclusion criteria were titles/abstracts relevant to the review question and two or more arm clinical trial. Exclusion criteria were the following: no computable data recorded and subjects of both groups not followed up in the same way. From the accepted trials, datasets were analysed concerning clinical precision and internal validity. Eleven trials were accepted. From these, 15 dichotomous datasets were extracted. Relative risk with 95% confidence interval of nine datasets showed no statistically significant differences in outcome between the treatment and control group after 6 months-1.32 years. Five showed a statistically significant difference (p < 0.05), favouring resin composite bonding after 12 and 18 months. One favoured RM-GIC after 10 months. Meta-analysis found no difference in the failure rate between the two treatment groups after 12 months (RR, 1.11; 95% CI, 0.87-1.42; p = 0.40) and found in favour of composite resin adhesive after >14 months (RR, 2.25; 95% CI, 1.60-3.17; p < 0.00001). All trials had poor internal validity due to selection and detection/performance bias risk. The current evidence suggests no difference between the types of materials after 12 months but favours composite resin adhesives after a >14-month period. However, its risk of selection and detection/performance bias are high, and all results need to be regarded with caution. Further high quality randomised control trials addressing this topic are needed. The clinical relevance of this study is that RM-GIC may have the same clinical debonding (failure) rate as composite resin adhesives after 1 year when used for bonding of orthodontic brackets.