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Low-quality evidence suggests that amalgam has increased longevity compared with resin-based composite in posterior restorations

Ying J. Wong, MS, DDS, MAGD .


Systematic Review Conclusion

Posterior resin-based composite restorations had decreased longevity and a greater incidence of secondary caries compared with amalgam restorations. With regard to fractures, there was no statistically significant difference between the 2 restorative materials in follow-up of 12 months or more.

Critical Summary Assessment

The results of this systematic review indicate that the life span of posterior resin-based composite restorations is shorter than that of amalgam restorations (risk ratio [RR], 0.46; 95% confidence interval [CI], 0.28-0.78; P = .003), whereas the incidence of secondary caries is higher (RR, 0.23; 95% CI, 0.18-0.30; P < .00001).

Evidence Quality Rating

Limited Evidence

This summary is published in the Journal of the American Dental Association and can be accessed at:

Critical Summary Publication Date:


These summaries are not intended to, and do not, express, imply, or summarize standards of care, but rather provide a concise reference for dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. American Dental Association © 2019