IADR Abstract Archives

Fatigue Damage and Micro-Leakage Study of Resin-Based Composite Crowns

Objectives: The most common causes for failure of dental restorations and recurrence of decay are fatigue-induced damage and marginal micro-leakage of oral fluids. Resin-based composite (RBC) has favorable aesthetic and mechanical properties for use in crowns. A major concern of RBC is its long-term stability. This study investigates contact damage and micro-leakage of the RBC crowns under mouth-motion fatigue with a contact-slide-liftoff action in wet environments.

Methods: 16 RBC crowns (Paradigm MZ100 Composite, 3M/ESPE) were CAD/CAM-machined using a standard profile scanned from a tooth prepared for crown cementation (first maxillary molar, tooth number 3). Adjustments were made to accommodate a 50µm thick cement layer. RBC crowns were cemented (RelyX™ Unicem Aplicap, 3M/ESPE) to water-aged (60 days) resin-based composite bases (Tetric EvoCeram, Ivoclar Vivadent) fabricated from impressions of the prepared tooth. A mouth-motion simulator was used to apply a cyclic load of 200N for 200k and 1M cycles (WC spherical indenter, r=3.18mm) to the mesio-buccal cusp ridge of the crown.

Results: Optical microscopy of the occlusal surface revealed wear facets, localized deformation, and incomplete ring cracks at the contact area. Specimens were sectioned along the contact site and dye infiltrated for sub-surface damage evaluation. 200k loading cycles specimens exhibited minimal material loss due to wear and partial cone cracks penetrating ~25% of crown thickness. Specimens that underwent 1M loading cycles showed greater material loss and partial cone cracks penetrating ~30% of crown thickness. Neither specimens displayed marginal micro-leakage. Traces of interfacial de-lamination not extending to the margins were observed, predominantly at the intaglio surface beneath occlusion.

Conclusions: CAD/CAM RBC crowns withstand long-term, high force occlusion in wet conditions. Occlusal contact damage did not reach the crown-tooth interface. Minimal internal adhesive de-lamination was observed, however no marginal micro-leakage was present. Supported by NYUCD Dean's Award, NIH/NIDCR-5R01DE17925-2, and NSF/CMMI-0758530.


IADR/AADR/CADR General Session
2009 IADR/AADR/CADR General Session (Miami, Florida)
Miami, Florida
2009
120
Prosthodontics Research
  • Davydova, Nataliya  ( New York University, New York, NY, USA )
  • Thompson, Van  ( PEARL Network, New York University, College of Dentistry, New York, NY, USA )
  • Zhang, Yu  ( New York University, New York, NY, USA )
    • Oral Session
    Arthur R. Frechette Research Awards Finalists
    04/01/2009