Biomechanical Analysis of Maxillary Dental Implants with Buccal Fenestration Defects

Biomechanical Analysis of Maxillary Dental Implants with Buccal Fenestration Defects
11 March 2005
S.-H. CHANG, C.-L. LIN, Y.-C. KUO, and W.-K. SU, Chang Gung University and Hospital, Taoyuan, Taiwan
IADR
Objectives: The aim of this study was to analyze the biomechanics of a maxillary dental implant and the surrounding bone with or without the buccal fenestration defects by non-linear finite element (FE) analysis. Methods: FE models of a Frialit-2 implant, replacing the missing maxillary second premolar, with no bony fenestration, 45% buccal bony fenestration or an angled abutment were conducted. Contact elements (frictional surface) were used to simulate the realistic interface conditions within the implant system. The mechanical responses within the implant system and surrounding bone were observed for axial and lateral simulated occlusal forces. Results: The simulated results indicated that the stress and strain values within the implant, alveolar bone and the prosthesis under lateral occlusal loads were 2.2 to 18 times higher than those of axial loads. The stress value of the implant compartments and the strain value of cortical bone of implant with bony fenestration were less than those without fenestration defects. This phenomenon was caused by the increase of cortical anchorage at the bottom of the implant fixture. In models using angled abutment, the stress and strain values of the implant, cortical and cancellous bone were all less than those in the models with or without bony fenestration defects. However, the stress values of abutment screw increased 3.27 times as a result of bending effect accompanied with angled abutment regardless of axial or lateral loads. Conclusions: Base on the biomechanical point of view, the stress and strain would not arise in implants with buccal bony fenestration defects and increased cortical anchorage. The risk of bony microfracture and resultant loss of osseointegration might not be as high as consideration in traditional concept. Clinicians should be aware of the increase of stress of the abutment screw in implants with angled abutments might cause technical failures.