title: Dynamic fatigue performance of implant-abutment assemblies with different tightening torque values.
abstract: Implant-abutment assemblies are usually subject to long-term cyclic loading. To evaluate the dynamic fatigue performance of implant-abutment assemblies with different tightening torque values, thirty implant-abutment assemblies (Zimmer Dental, Carlsbad, CA, USA) were randomly assigned to three tightening groups (24 Ncm; 30 Ncm; 36 Ncm), each consisted of 10 implants. Five specimens from each group were unscrewed, and their reverse torque values recorded. The remaining specimens were subjected to a load between 30 N~300 N at a loading frequency of 15 Hz for 5 × 10(6) cycles. After fatigue tests, residual reverse torque values were recorded if available. In the 24 Ncm tightening group, all the implants fractured at the first outer thread of the implant after fatigue loading, with fatigue crack propagation at the fractured surface showed by SEM observation. For the 30 Ncm and 36 Ncm tightening groups, a statistical significant difference (p<0.05) between the unloaded and loaded groups was revealed. Compared with the unloaded specimens, the specimens went through fatigue loading had decreased reverse torque values. It was demonstrated that insufficient torque will lead to poor fatigue performance of dental implant-abutment assemblies and abutment screws should be tightened to the torque recommended by the manufacturer. It was also concluded that fatigue loading would lead to preload loss.
authors.affiliation: Department of dental materials, School and Hospital of Stomatology, Peking University, Beijing, China National engineering Laboratory for Digital and Material Technology of Stomatology, Peking University, Beijing, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Xia
authors.affiliation: Department of dental materials, School and Hospital of Stomatology, Peking University, Beijing, China National engineering Laboratory for Digital and Material Technology of Stomatology, Peking University, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.affiliation: Department of dental materials, School and Hospital of Stomatology, Peking University, Beijing, China National engineering Laboratory for Digital and Material Technology of Stomatology, Peking University, Beijing, China.
authors.forename: Shenpo
authors.initials: S
authors.lastname: Yuan
authors.affiliation: Department of dental materials, School and Hospital of Stomatology, Peking University, Beijing, China National engineering Laboratory for Digital and Material Technology of Stomatology, Peking University, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Bai
authors.affiliation: Department of dental materials, School and Hospital of Stomatology, Peking University, Beijing, China National engineering Laboratory for Digital and Material Technology of Stomatology, Peking University, Beijing, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
mesh_terms: D001863:Bone Screws; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design / Q000295:instrumentation* / Q000379:methods; D003757:Dental Implantation / Q000295:instrumentation* / Q000379:methods*; D017266:Dental Prosthesis; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D019544:Equipment Failure Analysis; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013499:Surface Properties; D019415:Torque
keywords: Dental implants; fatigue testing; preload; reverse torque value