Tatsuya Matsuzaki1, Yasunori Ayukawa2, Yasuyuki Matsushita3, Nobuo Sakai4, Maki Matsuzaki3, Tomohiro Masuzaki5, Takuya Haraguchi3, Yoichiro Ogino1, Kiyoshi Koyano3. 1. Section of Fixed Prosthodontics, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan. 2. Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan. Electronic address: ayukawa@dent.kyushu-u.ac.jp. 3. Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan. 4. Kyushu Institute of Technology, Fukuoka, Japan. 5. Department of Oral and Maxillofacial Prosthodontics, Field of Oral and Maxillofacial Rehabilitation, Advanced Therapeutic Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
Abstract
PURPOSE: Much research has been invested in determining the effects of postoperative loading of implants and whether this loading contributes to implant failure, but the issue remains controversial. The present study aimed to elucidate whether cyclic lateral loading of an implant causes bone resorption or bone formation at various loading magnitudes, using a finite element method (FEM) and peri-implant morphologic and morphometric analyses. METHODS: An FEM model was created using Digital Imaging and Communications in Medicine (DICOM) data of rabbit tibia. For the animal study, implants were inserted into rabbit tibia and, after osseointegration, were subjected to lateral cyclic loading of 20N, 40N or 60N. RESULTS: Bone-implant contact was significantly higher in both 40N and 60N groups. Bone-abutment contact (BAC) was extraordinarily observed in all experimental groups. Bone height was higher than the implant platform level at higher levels of loading (60N). Among the three experimental groups, those receiving 40N loading had the highest bone height and BAC. Larger BAC values were observed on the compressive side than the tensile side. CONCLUSIONS: Peri-implant bone formation was enhanced with increased loading, with bone formation predominantly on the compressive side. BAC was highest in the 40N group, implying existence of a loading threshold for peri-implant bone formation and resorption.
PURPOSE: Much research has been invested in determining the effects of postoperative loading of implants and whether this loading contributes to implant failure, but the issue remains controversial. The present study aimed to elucidate whether cyclic lateral loading of an implant causes bone resorption or bone formation at various loading magnitudes, using a finite element method (FEM) and peri-implant morphologic and morphometric analyses. METHODS: An FEM model was created using Digital Imaging and Communications in Medicine (DICOM) data of rabbit tibia. For the animal study, implants were inserted into rabbit tibia and, after osseointegration, were subjected to lateral cyclic loading of 20N, 40N or 60N. RESULTS: Bone-implant contact was significantly higher in both 40N and 60N groups. Bone-abutment contact (BAC) was extraordinarily observed in all experimental groups. Bone height was higher than the implant platform level at higher levels of loading (60N). Among the three experimental groups, those receiving 40N loading had the highest bone height and BAC. Larger BAC values were observed on the compressive side than the tensile side. CONCLUSIONS: Peri-implant bone formation was enhanced with increased loading, with bone formation predominantly on the compressive side. BAC was highest in the 40N group, implying existence of a loading threshold for peri-implant bone formation and resorption.