Long Term Clinical Evaluation of Glass-Fiber-Reinforced Restorations

Objectives: The advantages of aesthetic restoration materials are good biocompatibility and lack of toxicity compared to metal restorations. Glass-fiber-reinforced composite material Targis/Vectris (Ivoclar-Vivadent, FL) were observed using a microscope and the composition was analyzed. As a result, it was judged that the material was good for clinical use. This material was used in dental treatments in 1997. However, the Glass-fiber-reinforced restorations often fractured. The purpose of this study was to evaluate the clinical strength of the Glass-fiber-reinforced restorations by Cohort analysis. Methods: The Glass-fiber-reinforced restorations were made according to the manual of the manufacturer. 29 patients who had 73 the Glass-fiber-reinforced restorations were investigated on by questionnaire survey, from a period of June 25th, 1999 up to September 7th, 2000 at Aichigakuin University dental hospital. Results: These restorations were investigated after a maximum of 8 years. 35 out of 73(47.9%) of the restorations were fractured, including cracks and chipping. 6 out of 14 inlays were fractured (42.9%). 14 out of 43 crowns were fractured (32.5%). 15 out of 16 bridges were fractured (93.8%). Survival rate was calculated according to the Kaplan-Meier Product-Limit method. 94% of crowns, 82% of inlays and 56% of bridges will still not have broken in 3 years time, and 71% of crowns, 57% of inlays and 12% of bridges will still not have broken in 6 years time. According to log-rank test when the risk of hazard is 3%, there is no significant difference between crowns and inlays, but, there is a significant difference between crowns and bridges, and between inlays and bridges. Conclusion: Clinicians should not use materials developed by new concept or techniques too quickly. Instead we think that long-term clinical evaluation is needed for safety and durability.