BPA-containing resin not needed to bond retainers

Jan 28 2013

By Joanna Lyford, Senior medwireNews Reporter

Metal lingual retainers can be bonded successfully without the use of composite liquid resin, a study by Chinese researchers indicates.

Indeed, the survival rate for retainers bonded without resin was actually slightly longer than that for retainers bonded in the traditional manner.

The liquid resins used in dentistry contain bisphenol A diglycidylmethacrylate (BPA), a compound with putative carcinogenic and estrogenic effects. There is therefore a public health imperative to minimize the use of BPA-containing products.

In this study, Alexander Tang (University of Hong Kong, China) and co-workers investigated the viability of bonding retainers without the use of liquid resin.

They recruited 38 patients and randomly assigned them to have retainers fixed either with a composite paste and liquid resin (n=20; resin group) or with just the composite paste (n=18; no-resin group).

Patients were observed for 5 years, during which time 50% of the retainers in the resin group and 60% of those in the no-resin group had bond failures. However, the between-group difference was not statistically significant, report Tang et al.

Overall, 13.6% of bonded tooth surfaces had bond failures in the resin group versus 14.9% in the no-resin group; again the difference was not significant.

Furthermore, the median retainer survival time was 43 months in the resin group compared with 47 months in the no-resin group, again supporting the similar durability of the two approaches.

Writing in the American Journal of Orthodontics & Dentofacial Orthopedics, Tang et al conclude that the bonding of lingual retainers does not need to involve liquid resin.

"The bonded retainers in the test group remained in place for a clinically acceptable time without liquid resin. The retainers in the test group even tended to show a more favorable survival rate than those in the control group," they write.

"Considering the potential hazards of BPA, elimination of the contribution of the liquid resin in the overall BPA release without compromising the clinical longevity of the retainer therefore would imply a more biologic approach of bonding procedures for the benefit of clinicians and, more importantly, for patients."

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