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Inside Dentistry
May 2009
Volume 5, Issue 5

Increasing the Longevity of Restorations by Minimal Intervention: A Two Year Clinical Trial

Howard E. Strassler, DMD

Moncada G, Fernández E, Martín J, et al. Oper Dent. 2008;33:258-264.


This investigation assessed the effectiveness of alternative treatments for the replacement of amalgam and resin-based composite restorations. Sixty-six patients (age 18 to 80 years, mean = 26.6) with 271 (amalgam [n = 193] and resin-based composite [n = 78]) defective restorations were randomly assigned to one of five different treatment groups: A) Repair (n = 27); B) Sealing of margins (n = 48); C) Refurbishing (n = 73); D) Replacement (n = 42) and E) Untreated (n = 81). USPHS/Ryge criteria were used to determine the quality of the restorations. Two calibrated examiners (Cohen’s Kappa 0.74) assessed the restorations independently at the beginning of the study (baseline) and at 2 years after treatment using seven parameters from the USPHS/Ryge criteria (Marginal Adaptation, Anatomic Form, Roughness, Marginal Stain, Occlusal Contact, Secondary Caries and Luster).

RESULTS: Two-hundred and fifty-six restorations (178 amalgam and 78 resin-based composite) were examined at the 2-year recall exam. The sealing of marginal defects showed significant improvements in marginal adaptation (P < .05). Refurbishing of the defective restorations significantly improved anatomic form (P < .0001), luster (P < .016), marginal adaptation (P < .003) and roughness (P < .0001). The repair significantly improved anatomic form (P < .002) and marginal stain (P < .002). Replacement showed significant improvements for all parameters (P < .05). The Untreated group showed significant deterioration on marginal adaptation (P < .013).

CONCLUSIONS: The 2-year recall examination showed that sealant, repair, and refurbishing treatments improved the clinical properties of defective amalgam and resin-based composite restorations by increasing the longevity of the restorations with minimal intervention.


Minimally invasive or minimal intervention dentistry has become an increasingly important concept when making restorative decisions. For a patient with discolored teeth, bleaching is the first option considered before a more invasive treatment option of bonded composite or porcelain veneers. For pit-and-fissure caries, sealants or preventive resin restorations is a first choice when the pit and fissure has an incipient carious lesion.

Total replacement of moderate- and large-sized restorations because of small, isolated defects in a current restoration may be more aggressive and may not be necessary. Certainly, every time we replace an existing restoration, we are putting the pulp at risk. In the past it has been suggested that instead of replacing defective restorations, we should be repairing only the defective areas.

Moncada and coworkers provide us with insight about the potential to repair existing amalgam and composite resin restorations. Their 2-year findings suggest that sealing margins, repair, and refurbishing treatments for defective amalgam and resin-based composite restorations increased the longevity of the restorations with minimal intervention. This research project confirmed other findings that have been reported looking at similar parameters for repair of less than ideal marginal adaptations of composite resin and amalgam restorations.1,2


1. Gordan VV, Shen C, Riley J 3rd, Mjör IA. Two-year clinical evaluation of repair versus replacement of composite restorations. J Esthet Restor Dent. 2006;18: 144-153.

2. Gordan VV, Riley J 3rd, Blaser PK, Mjör IA. 2-year clinical evaluations of alternative treatments to replacement of defective amalgam restorations. Oper Dent. 2006; 31:418-425.

About the Author

Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School
Baltimore, Maryland

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