24 January 2022

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A cohort study regarding long term chipping and failure rates of implant-supported and combined tooth implant-supported metal-ceramic and ceramic fixed dental prostheses

Co-authors: A. Comba, F. Del Bianco

Lorenzo Breschi

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Professor Rammelsberg and his group of research conducted  a literature research regarding long term failure and chipping rates of fixed dental prosthesis (FPDs) tooth, implant or tooth-implant supported. The research group from Heidelberg University found that tooth-implant-supported fixed dental prostheses have been associated with an increased risk of long-term failure even if results were regarding a small sample of 72 prostheses. In addition, high chipping rates have been reported for ceramic fixed dental prostheses. However, the data founded by the authors  were sparse, in particular  long-term results on the performance of monolithic zirconia implant-supported FDPs are lacking. For these reasons the purpose of the observational cohort study conducted by  Rammelsberg et al.  was to investigate the failure and chipping rates of ceramic FDPs compared with those of metal-ceramic FDPs supported by implants or by a combination of teeth and implants. Furthermore, attention was paid to the prognosis of monolithic ceramic FDPs and to FDPs with partial veneers restricted to the buccal surface.

Material & Methods
The German researchers selected four hundred thirty-four fixed dental prostheses placed in 324 patients (mean age: 60.8 years) from a prospective clinical long-term study comprising 213 implant-supported fixed dental prostheses, 66 implant-supported cantilever fixed dental prostheses, and 155 tooth-implant-supported fixed dental prostheses. Kaplan-Meier curves were used by the authors to estimate the survival probability and the chipping-free survival rate of the fixed dental prostheses.

Results
During the observation period of 0.5 to 12.6 years (mean: 4.26 years), the Rammelsberg et al.  noticed that 17 fixed dental prostheses failed because of implant failure (n=6), tooth loss (n=5), major chipping (n=5), or abutment screw loosening (n=1). Survival probability found by the authors was 96% after 5 years and 91% after 10 years. Chipping (n=61) was significantly affected by the framework material and type of veneer (P=.001). After 5 years, the greatest incidence of chipping (39%) was observed by the authors for zirconia fixed dental prostheses with a complete veneer, instead of a lower incidence of chipping observed for zirconia fixed dental prostheses with a partial veneer or monolithic design.

Conclusion
The German researchers concluded that Implant-supported and combined tooth-implant-supported fixed dental prostheses have promising long-term survival rates. According to the results collected from the authors from Heidelberg University chipping seems to occur less frequently in monolithic or partially veneered fixed dental prostheses than in fixed dental prostheses with complete veneers. (J Prosthet Dent 2021;126:196-203)

For more information: Long-term chipping and failure rates of implant-supported and combined tooth–implant-supported metal-ceramic and ceramic fixed dental prostheses: A cohort study