03 August 2023

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Preheated composite resins as luting materials for indirect restorations: a systematic review

By Lorenzo Breschi and Carlo D’Alessandro

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The type of luting material and the cementation techniques are crucial factors contributing to the long-term prognosis of indirect restorations. An ideal cement should create a stable connection between the tooth abutment and the restoration, enabling a reliable retention, good fracture resistance and reduced microleakage.

In recent years, the use of preheated resin composites as a luting agent for indirect restorations has gained significant attention as an alternative to resin cements. The preheating technique, where the resin composite material is heated to a specific temperature prior to placement, offers unique advantages in terms of handling characteristics, polymerization shrinkage and mechanical strength.

The reduced viscosity and the high filler content contribute to obtaining optimal clinical performances. The temperature at which the resin composite is heated can vary depending on the specific material and manufacturer's recommendations.

Although the physical and mechanical properties of different resin composite with various preheating techniques have been evaluated, there is no evidence regarding their influence on the adaptation of indirect restorations when used as luting materials. Some of the main concerns of this approach are the greater film thickness compared with that of resin cement and the marginal fit. In this regard, Souza et al. have conducted a systematic review to answer the question: Does the use of preheated restorative resin composite as a luting material influence the adaptation of fixed dental prostheses?

Materials and methods

Published articles were selected from seven databases and non-peer-reviewed literature. Only studies directly comparing the adaptation of fixed dental prostheses cemented with preheated restorative resin composites or resin cements were considered eligible for inclusion. Both in vivo and in vitro studies were considered. The risk of bias of each included study was assessed on a nine-item checklist.

Results

A total of four in vitro articles met the inclusion criteria of the review process. Results of three studies indicated that preheated resin composites produced a greater discrepancy than resin cements, while the improved the adaptation of fixed dental prostheses was found in the remaining study. Even though all included studies had a medium risk of bias, the number of investigations was limited thus requiring further insights. Moreover, the elevated level of heterogeneity among the studies precluded meta-analysis on variables such as the formulation of the resin materials or the heating time and temperature.

Conclusion

Within the limitation of this study, the authors concluded that the use of preheated resin composites as luting material negatively influences the adaptation of fixed dental prostheses and suggested resin cements as the more suitable choice for cementation of indirect restorations. Further research and clinical trials with better methodological designs are essential to validate this evidence.

Souza TJS, Freitas ADS, Ferreira DMTP, Maia LC, Rabello TB. “Does the use of preheated restorative resin composite as a luting agent influence the adaptation of fixed dental prostheses? A systematic review.” J Prosthet Dent. 14 March 2022. DOI: https://doi.org/10.1016/j.prosdent.2022.02.008