| Summary: | 碩士 === 高雄醫學大學 === 牙醫學研究所 === 96 === Nowadays, dental implant is prosperously developed. However, there is still great disagreement on relative position between implants and alveolar bone. Most dentists can only decide the relative position by following suggestions from manufacturers, or their clinical experiences. The purpose of this study was to investigate biomechanical effects of different relative positions between implants and alveolar bone on stress distribution in implants and alveolar bone, using three- dimensional (3-D) finite element (FE) analysis.
Twenty FE models including four cortical bone thickness (0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm) and five relative positions between implants and alveolar bone (1. supra 0.5: the top of implant is higher than alveolar bone crest with 0.5 mm, 2. supra 1.0: the top of implant is higher than alveolar bone crest with 1.0 mm, 3. even: the tops of implant and alveolar bone crest are in the same level, 4. sub 0.5: the top of implant is lower than alveolar bone crest with 0.5 mm and 5. sub 1.0: the top of implant is lower than alveolar bone crest with 1.0 mm.) were analyzed. The force was applied on mesiobuccal cusp and distobuccal cusp with 100 Newton, respectively. The simulated load was applied either vertically along the long axis or obliquely 45 degree from buccal direction.
The results showed that the stress was concentrated around the neck of implant. And the increase of stress was associated with higher implant position relative to alveolar bone. In cortical bones, the stress was smaller and equally distributed with implant position “even”. While implanting the implant in the position of “supra 1.0”, the stress was larger and focused on certain area. In the conditions of “sub 1.0”, “sub 0.5” and “supra 0.5”, the results of stress analysis was depending on the direction of simulating force.
In conclusion, the distribution of stress applied on alveolar bone around the implant is more biomechanically acceptable when the implant position is “even”. However, considering anatomy limitation and esthetics, it is appropriate to evaluate the occlusion pattern before determining the relative position of implant and alveolar bone.
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