Influence of the connection design and titanium grades of the implant complex on resistance under static loading.
OBJECTIVE
The purpose of this study was to evaluate the resistance to deformation under static overloading by measuring yield and fracture strength, and to analyze the failure characteristics of implant assemblies made of different titanium grades and connections.


METHODS
Six groups of implant assemblies were fabricated according to ISO 14801 (n=10). These consisted of the combinations of 3 platform connections (external, internal, and morse tapered) and 2 materials (titanium grade 2 and titanium grade 4). Yield strength and fracture strength were evaluated with a computer-controlled Universal Testing Machine, and failed implant assemblies were classified and analyzed by optical microscopy. The data were analyzed using the One-way analysis of variance (ANOVA) and Student's t-test with the level of significance atP=.05.


RESULTS
The group IT4Shad the significantly highest values and group IT2 the lowest, for both yield strength and fracture strength. Groups IT4Nand ET4 had similar yield and fracture strengths despite having different connection designs. Group MT2 and group IT2 had significant differences in yield and fracture strength although they were made by the same material as titanium grade 2. The implant system of the similar fixture-abutment interfaces and the same materials showed the similar characteristics of deformation.


CONCLUSIONS
A longer internal connection and titanium grade 4 of the implant system is advantageous for static overloading condition. However, it is not only the connection design that affects the stability. The strength of the titanium grade as material is also important since it affects the implant stability. When using the implant system made of titanium grade 2, a larger diameter fixture should be selected in order to provide enough strength to withstand overloading.
Department of Biomaterials & Prosthodontics, Kyung Hee University Hospital at Gangdong, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
Su-Jung
0000-0002-4111-2231
SJ
Park
Department of Biomaterials & Prosthodontics, Kyung Hee University Hospital at Gangdong, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
Suk-Won
0000-0003-2726-3567
SW
Lee
Department of Biomaterials & Prosthodontics, Kyung Hee University Hospital at Gangdong, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
Richard
0000-0002-8381-723X
R
Leesungbok
Department of Biomaterials & Prosthodontics, Kyung Hee University Hospital at Gangdong, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
Su-Jin
0000-0003-2128-1561
SJ
Ahn
Dental Implant-Abutment Connection; Implant failure; Static loading; Titanium grade; Yield strength