FEA Prediction of Crestal Bone Retention around Dental Implants

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FEA Prediction of Crestal Bone Retention around Dental Implants
13 March 2004
H. ALEXANDER, Orthogen Corporation, Springfield, NJ, USA, and J. RICCI, New York University, USA
IADR
Objectives: Canalicular flow excites osteocytes to produce anabolic factors that recruit osteoblasts and inhibit osteoclasts. Damage to the network causes osteocyte death and recruitment of osteoclasts. Von Mises stress predicts yield damage of bone. The objective is to minimize crestal bone stress and micromotion through implant collar surface treatment. Methods: Bone and soft tissue response to two dental implants has been evaluated through finite element analysis (FEA). The two implants are a V thread, machined collar implant (S) and a laser microtextured tapered, reverse buttress thread implant (LL) (LaserLokǗ˘, BioLok Intl.). LL has a 2mm collar that has been laser micromachined with patterns shown to improve bone and soft tissue attachment. 80 Newtons axial loading and 80 Newtons side loading were applied 6 mm above the collar. Two collar/bone interfaces were considered: slip and no slip, to simulate the S and LL surfaces, respectively. Von Mises stress was computed as a ǃ?bone damage indicator.ǃ? Results: For the 80 Newton axial load, the maximum LL crestal bone stress (4 MPa) is lower than that of S (12.9 MPa). These stresses are, however, still in a safe range for fatigue damage. For the 80 Newton side load, the crestal bone around S is well into the yield range (140.2 MPa). The crestal bone stress of LL (22.6 MPa) is significantly below the yield region, 75-113 MPa. Conclusion: FEA predicts that stress overload can result in loss of crestal bone. Attaching bone to the collar with LL is predicted to diminish this effect, benefiting crestal bone retention. Comparing these results with those of a canine implantation study has validated this prediction with a correlation between the FEA prediction and the canine histology. These implant design and surface treatment changes should result in retention of crestal bone and the aesthetics of the interdental papilla.