Clinical Longevity of Complex Direct Posterior Resin Composite and Amalgam Restorations: A Systematic Review and...

Area of Science:

• Dental Materials Science
• Clinical Dentistry
• Evidence-Based Dentistry

Background:

• Resin composites (RC) are increasingly used for complex dental restorations, including cusp coverage.
• Conflicting literature exists regarding the performance of multisurface posterior resin composite (RC) versus amalgam (AM) restorations.
• Assessing the clinical performance of these materials in complex restorations is crucial.

Purpose of the Study:

• To systematically review and perform a meta-analysis on the clinical performance of complex (two or more surfaces) direct posterior resin composite and amalgam restorations in permanent teeth.
• To compare the survival rates and failure modes of these restorations.

Main Methods:

• Prospective randomized controlled trials (RCTs) with a minimum three-year follow-up and at least 20 restored teeth per material were included.
• Searches were conducted across five major databases and manual searches.
• Risk of bias was assessed using the Cochrane Risk of Bias Tool, and random-effects meta-analyses were performed.

Main Results:

• Fifteen RCTs met the inclusion criteria, but only two directly compared AM and RC restorations.
• A trend towards higher failure rates for multisurface RC restorations was observed, but it was not statistically significant (p=0.06).
• Common failure reasons for RC included secondary caries, restoration fracture, and tooth fracture; for AM, they were secondary caries and tooth fracture.

Conclusions:

• The overall quality of evidence is low due to the scarcity of comparative studies.
• Insufficient evidence exists to support the superiority of either resin composite or amalgam for complex posterior restorations.
• Further high-quality research directly comparing these materials is warranted.