3D Evaluation of Micro-Gap at The Implant-Abutment Connection Before and After Thermodynamic Cycling.

Abstract

To analyze the micro-gap changes between hybrid abutment crowns made of two materials and three internal taper connection implants each having different connection designs before and after thermodynamic loading. A total of 30 implants; ten each of Straumann Bone Level Implant-RC [STR]; GC AADVA Implant [AAD] and Astra-Tech OsseoSpeed EV [AST]were included in this laboratory study. Each implant has an internal taper connection, but their designs are slightly different. Five hybrid abutment crowns were fabricated using a lithium disilicate ceramic [LD] and five using a polymethyl methacrylate [PMMA] with CAD/CAM technologies for each implant system, providing six sample groups STR-LD, AAD-LD, AST-LD, STR-PMMA, AAD- PMMA and AST-PMMA. The micro-gap volume was measured using obtained micro-CT images before and after the thermodynamic loading equivalent to 4 months of clinical use. For comparisons Student's t test, One-Way Variance Analysis and Tukey's test were used. The greatest micro-gap volume increase (%3.405ű1.567) in the AST-LD group and the lowest increase (%0.45ű0.373) in the STR-PMMA group were recorded. A statistically significant difference in micro-gap increase was not detected among PMMA and LD groups: (t-test: p=0,273) for This peer-reviewed, accepted manuscript will undergo final editing and production prior to print publication. STR-LD/STR-PMMA, (t-test: p=0,374) for AAD-LD/AAD-PMMA and (t-test: p=0,268) for AST-LD/AST-PMMA. However, the difference in the micro-gap increase between the different implant systems was statistically significant. The micro-gap between hybrid abutment crowns and implants increased short-term after thermodynamic cycling. Hybrid abutment crowns with different elastic modulus showed similar micro-gap increases. The geometric shape of the connection influenced the micro-gap increase.