| 1251 Stress Generation in Primary Maxillary Canines with Cervical Restorations of Varying Moduli | ||
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R.B. BERSON, and A.A. CAPUTO, UCLA School of Dentistry, Los Angeles, CA, USA Objectives: Abfractive forces have been shown to produce deleterious effects on restored cervical lesions. It has been suggested that the stiffness of the restoration in such cases could affect their longevity. The purpose of this investigation was to photoelastically assess the effects of restorative modulus on load induced stresses in primary canine teeth. Methods: Composite photoelastic models of a typical primary maxillary canine were made using individual simulant materials for enamel, dentin, periodontal ligament, and alveolar bone. The models included simulated standard conservative preparations for the restoration of facial gingival lesions. Cavity walls were prepared by air abrsion with 30 mm silica particles, cleansed, and then primed and coated with unfilled resin. The model teeth were restored using the following materials of disparate elastic moduli: a) low modulus, flowable composite (PermaFlo) and b) high modulus, hybrid composite (Herculite XRV). Three replications of each type of restored tooth were fabricated. Simulated masticatory forces were applied on the cusp in vertical and lateral directions. The resulting stress patterns were observed and recorded photographically in the field of a circular polariscope. Results: Prior to load application, similar polymerization induced shrinkage stresses were observed in all models. Under both axial and lateral cuspal loading, the higher modulus hybrid composite tended to concentrate stress along the gingival and proximal margins more than did the low modulus flowable composite. This effect was more pronounced with lateral than with axial loading. No significant differences were observed within each group of replicated restored models. Conclusions: These results suggest the use of a lower modulus composite resin to restore facial cervical lesions in primary maxillary canines to reduce localization of load induced stresses at the restoration margins. | ||
| Seq #123 - Properties of Polymers and Tooth Structure 3:45 PM-5:00 PM, Thursday, 7 March 2002 San Diego Convention Center Exhibit Hall C | ||
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Back to the Dental Materials: VIII - Others-Non-metallic Program
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