The influence of the framework thickness on surface strain of the 3-unit zirconia resin-bonded fixed dental prostheses under the functional loading

Kyoshi Matsukawa, DDS (1), Reina Nemoto, DDS, PhD (1), Kosuke Nozaki, DDS, PhD (2), Mariko Kubo, DDS (1), Tasuku Inagaki, DDS, PhD (1), Keiichi Yoshida, DDS, PhD (1), and Hiroyuki Miura, DDS, PhD (1)

(1) Fixed Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, and (2) Department of Inorganic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan

Purpose: The purpose of the present study was to optimize the form of a resin-bonded fixed dental prosthesis (RBFDP) frame by preparing various framework designs using ceria-stabilized tetragonal zirconia/alumina nano composite (Ce-TZP/Al) materials.
Materials and Methods: Six types of frameworks were fabricated as follows: 0.8-mm-thick metal (0.8M), 0.8-mm- and 0.5-mm-thick yttria-stabilized tetragonal zirconia polycrystal frameworks (0.8Y, 0.5Y) and 0.8- mm-, 0.5 -mm- and 0.3-mm- thick Ce-TZP/Al frameworks (0.8C, 0.5C, 0.3C). A load up to 200 N crosshead speed of 1.0 mm/min was applied to center of the palatal surfaces of the pontic of the RBFDPs by a universal testing machine. The strains of the RBFDPs during loading were measured and recorded by sensor interfaces. Then, the magnitudes of the maximum and minimum principal strain were calculated. A two-way analysis of variance (ANOVA) and a t-test with Bonferroni correction were used for the statistical analysis of strain, with a significance level at α = 0.05.
Results: In the canine, the magnitudes of the maximum principal strain of 0.8M were significantly higher than those in group 0.8Y. There were no significant differences among the 0.3C, 0.5Y, and 0.8M groups.
Conclusion: This report suggested that Ce-TZP/Al can improve the long-term prognosis of resin bonded fixed dental prostheses in the oral cavity due to its desirable mechanical and hydrothermal degradation-resistant characteristics, enabling the design of a resin bonded fixed dental prosthesis frame with a thickness of 0.3 mm.
(Asian Pac J Dent 2017; 17: 1-7.)
Key Words: resin-bonded fixed dental prosthesis, strain gage, zirconia ceramics.