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Margin analysis of posterior composites in vivo
J F Roulet1, B Salchow, M Wald
1Free University of Berlin.
Summary
Posterior composite restorations showed significant marginal defects and wear over time, with amalgam exhibiting margin fractures. These resin composites are not recommended for replacing Class II amalgam restorations due to leakage concerns.
Area of Science:
- Dental Materials Science
- Restorative Dentistry
- Micromorphology Analysis
Background:
- Posterior composite restorations are prone to polymerization shrinkage, a significant clinical limitation.
- Evaluating the marginal integrity and long-term performance of resin composites versus amalgam is crucial for clinical decision-making.
Purpose of the Study:
- To quantitatively compare the marginal micromorphology of two posterior resin composites (Occlusin and Coltène EX-D2) against amalgam (Dispersalloy) in Class II cavities.
- To assess the incidence of marginal defects such as excellent margin (EM), submargination (SM), margin fractures, and marginal openings (MO) over a seven-month period.
Main Methods:
- Thirty-three Class II cavities were restored using an incremental technique with Occlusin, Coltène EX-D2, or Dispersalloy.
- Replicas of the restorations were obtained at one week and seven months post-placement.
- Quantitative analysis of marginal micromorphology was performed using Scanning Electron Microscopy (SEM).
Main Results:
- Both resin composites initially exhibited a higher percentage of excellent margins (EM) compared to amalgam (p < 0.01).
- Over seven months, EM decreased significantly for all materials, with greater reduction in Coltène EX-D2 (14%) than amalgam or Occlusin (10%).
- Amalgam showed an increase in margin fractures (11.2%), while resin composites displayed increased submargination (Occlusin 18%, Coltène EX-D2 21%) and marginal openings (16% for composites), indicating wear and potential leakage.
Conclusions:
- The study confirms the inferior marginal micromorphology of Dispersalloy amalgam compared to the tested resin composites.
- Despite initial advantages, resin composites exhibited significant marginal degradation and wear, leading to marginal openings and potential leakage.
- Class II amalgam restorations should not be replaced with the specific resin composites evaluated in this study due to long-term marginal integrity concerns.