Initial stability and bone strain evaluation of the immediately loaded dental implant: an in vitro model study.
OBJECTIVE
The aim of this study was to evaluate the effects of cortical bone thickness and trabecular bone elastic modulus on the strain in the bone surrounding an immediately loaded implant. We also examined the correlations between bone structure and the following indices of primary implant stability: insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ).


METHODS
The ITV, PTV, and ISQ were measured in 24 artificial jaw bone models representing cortical bone with four thicknesses (0, 1, 2, and 3 mm) and trabecular bone with four elastic moduli (137, 47.5, 23, and 12.4 MPa). Two loading conditions were applied (force of 130 N applied vertically and at 45° laterally), and the strains in the crestal region were measured by rosette strain gauges with a data acquisition system.


RESULTS
When the cortical bone thickness and the elastic modulus of trabecular bone decreased, the bone strains increased by 10.3-52.1% and 39-73.1%, respectively, for vertical loading and by 35-62% and 42.4-56.2% for lateral loading. The cortical bone thickness has a stronger correlation (R(2) =0.95-0.71) with ITV, PTV, and ISQ than the elastic modulus of trabecular bone (R(2) =0.89-0.59).


CONCLUSIONS
The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the elastic modulus of trabecular bone; however, these parameters are not totally linearly correlated with ITV, PTV, and ISQ. The placement of an immediately loaded implant in cases with thin cortical bone and/or weak trabecular bone can induce extreme bone strains and may increase the risk of implant failure.
School of Dentistry, China Medical University and Hospital, Taichung, TaiwanDepartment of Materials Science and Engineering, Ming Dao University, Peetow Township, ChangHua, TaiwanDepartment of Dental Hygiene, China Medical University and Hospital, Taichung, TaiwanBiostatistics Center, China Medical University and Hospital, Taichung, TaiwanInstitute of Environmental Health, China Medical University and Hospital, Taichung, Taiwan.
Heng-Li
HL
Huang
School of Dentistry, China Medical University and Hospital, Taichung, TaiwanDepartment of Materials Science and Engineering, Ming Dao University, Peetow Township, ChangHua, TaiwanDepartment of Dental Hygiene, China Medical University and Hospital, Taichung, TaiwanBiostatistics Center, China Medical University and Hospital, Taichung, TaiwanInstitute of Environmental Health, China Medical University and Hospital, Taichung, Taiwan.
Yin-Yu
YY
Chang
School of Dentistry, China Medical University and Hospital, Taichung, TaiwanDepartment of Materials Science and Engineering, Ming Dao University, Peetow Township, ChangHua, TaiwanDepartment of Dental Hygiene, China Medical University and Hospital, Taichung, TaiwanBiostatistics Center, China Medical University and Hospital, Taichung, TaiwanInstitute of Environmental Health, China Medical University and Hospital, Taichung, Taiwan.
Dan-Jae
DJ
Lin
School of Dentistry, China Medical University and Hospital, Taichung, TaiwanDepartment of Materials Science and Engineering, Ming Dao University, Peetow Township, ChangHua, TaiwanDepartment of Dental Hygiene, China Medical University and Hospital, Taichung, TaiwanBiostatistics Center, China Medical University and Hospital, Taichung, TaiwanInstitute of Environmental Health, China Medical University and Hospital, Taichung, Taiwan.
Yu-Fen
YF
Li
School of Dentistry, China Medical University and Hospital, Taichung, TaiwanDepartment of Materials Science and Engineering, Ming Dao University, Peetow Township, ChangHua, TaiwanDepartment of Dental Hygiene, China Medical University and Hospital, Taichung, TaiwanBiostatistics Center, China Medical University and Hospital, Taichung, TaiwanInstitute of Environmental Health, China Medical University and Hospital, Taichung, Taiwan.
Kuan-Ting
KT
Chen
School of Dentistry, China Medical University and Hospital, Taichung, TaiwanDepartment of Materials Science and Engineering, Ming Dao University, Peetow Township, ChangHua, TaiwanDepartment of Dental Hygiene, China Medical University and Hospital, Taichung, TaiwanBiostatistics Center, China Medical University and Hospital, Taichung, TaiwanInstitute of Environmental Health, China Medical University and Hospital, Taichung, Taiwan.
Jui-Ting
JT
Hsu
D001696:Biomechanical Phenomena; D015519:Bone Density; D001842:Bone and Bones / Q000502:physiology*; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D066298:In Vitro Techniques; D003765:Models, Dental; D012044:Regression Analysis; D013314:Stress, Mechanical; D019415:Torque
D015921:Dental Implants