Orthodontic bracket failure rate after bonding with and without primer - A systematic review and meta-analysis

To compare the difference in failure rates between orthodontic brackets bonded with light-cured primer and those bonded without primer.

An electronic search of five databases and additional manual searches were performed until January 2024. Randomized and prospective non-randomized controlled trials directly comparing the bracket failure rate with and without primer. Two authors independently collected study characteristics by extracting outcome data from pre-defined sheets. After evaluating the risk of bias, the odds ratio and 95% confidence intervals (CIs) were calculated with random-effects models.

Four studies were evaluated using qualitative and quantitative analysis. The analysis included data from 199 patients (1691 brackets with primer and 1646 brackets without primer). Random effects of pooled meta-analysis demonstrated statistically significant differences in the bracket failure rates (odds ratio=1.50, p=0.010, [95% CI 1.10 to 2.05]). The risk of failure was 1.5 times greater when brackets were bonded without primer.

The results should be interpreted in the context of the limited sample size, even though there was a substantial difference in the failure rates of brackets with and without a primer, favouring the use of a primer. Furthermore, the validity of the finding may be limited by potential variables such as patient factors, clinician expertise, and isolation. More extensive research is required to validate these findings (PROSPERO CRD42024593134).