Crowns, Abutments'design Effects On Implant Displacement (In - Vitro)

The long - term success of implant restoration and related complications are closely related to the stress on implants. Natural teeth with a periodontal ligament are superior to implants in buffering occlusal stress on alveolar bone. Elastic implant crown materials have been reported to relieve stress around implants. This study focuses on comparing displacement values of single implant crowns with diverse materials and abutment designs, exploring if elastic crown materials can imitate the periodontal ligament's cushioning function. Personalized and prefabricated abutments, along with zirconia, resin - based ceramic, and PEEK crown materials, were used. CAD/CAM - made implant crowns with different central fossa thicknesses and corresponding abutments formed 12 groups (120 samples). A testing machine measured displacement, analyzed by ANOVA and Tukey's test. ANOVA indicated that both crown material (F = 284.88, P = 1.39×10⁻⁴³) and abutment design (F = 48.63, P = 6.56×10⁻²⁰) significantly influenced implant displacement. The 3mm PEEK crown group had the highest displacement (0.331 ± 0.024 mm), and the 3mm zirconia group the lowest (0.143 ± 0.002 mm). The finished - abutment group's displacement was similar to that of 1 - mm zirconia and resin - based ceramic crown groups. For PEEK and resin - based ceramic, the thicker they are, the more they deform; for zirconia, it's reversed. The 3mm PEEK crown's displacement nears the periodontal ligament's thickness (0.38 mm), suggesting elastic crowns might replicate its cushioning effect.