David Jones

To investigate the effects of abutment taper angles on the fracture strength of dental implants with TIS (taper integrated screwed-in) connection. Thirty prototype cylindrical titanium alloy 5.0mm-diameter dental implants with different TIS-connection designs were divided into six groups and tested for their fracture strength, using a universal testing machine. These groups consisted of combinations of 3.5 and 4.0mm abutment diameter, each with taper angles of 6°, 8° or 10°. 3-Dimensional finite element analysis (FEA) was also used to analyze stress states at implant-abutment connection areas. In general, the mechanical tests found an increasing trend of implant fracture forces as the taper angle enlarged. When the abutment diameter was 3.5mm, the mean fracture forces for 8° and 10° taper groups were 1638.9N±20.3 and 1577.1N±103.2, respectively, both larger than that for the 6° taper group of 1475.0N±24.4, with the largest increasing rate of 11.1%. Furthermore, the difference between 8° and 6° taper groups was significant, based on Tamhane's multiple comparison test (P