RESUMO
Objective@#To provide a reference for a suitable alternative treatment choice for implant-supported prostheses, and to explore the influence of 3 types of prosthetic material on the stress distribution around implant.@*Methods@#The implant-abutment analogs were embedded individually into photoelastic resin blocks, which were medical pure titanium castings reproducing the surface and outline of implant (diameter 4.3 mm, length 11.5 mm) and esthetic abutment (regular profile, 1 mm). The prostheses were divided into 3 groups according to the type of prosthetic material. Each group consisted of 5 samples. The samples of composite resin ceramic and zirconia group were milled by chair-side computer aided design and computer aided manufacture (CAD/CAM) system. The samples of porcelain-fused-to-metal crown group were made manually and a pre-arranged silicone rubber impression of CAD/CAM crown would guide to shape the veneer porcelain. Each set was submitted to a 300 N compressive load axially or obliquely (75°). The stress value in the peri-implant bone at the level of the neck, neck1/3, middle1/3 and root1/3 of the sections (0.5, 1.5, 2.5, 3.5 mm) from implant was analyzed by digital photoelasticity, and the stress cushioning effect of 3 types of prosthetic material was comprehensively evaluated.@*Results@#The time spent reaching the stress peak of composite resin ceramic group [(1.58±0.08) s, axially; (2.75±0.21) s, obliquely] was larger than that of the zirconia group [(1.40±0.12) s, axially; (2.30±0.25) s, obliquely] (P<0.05) under the same download mode. Although there were no significant differences in equivalent stress values of the measurement points among the three groups (P>0.05), a downward trend of equivalent stress values of composite resin ceramic group was observed compared to zirconia group, regardless of load type. When loaded obliquely, the highest degree of stress concentration at the level of the neck of implant were found in the porcelain-fused-to-metal crown group.@*Conclusions@#Within the limitations of this study, composite resin ceramic was more beneficial to the biomechanical behavior of implant in stress buffer compared to zirconia.