Effect of compromised cortical bone on implant load distribution.
OBJECTIVE
To investigate photoelastically the difference in load distribution of dental implants with different implant neck designs in intact and compromised bone.


METHODS
Composite photoelastic models were fabricated using two different resins to simulate trabecular bone and a 1-mm thick layer of cortical bone. The following parallel-sided, threaded implants were centrally located in individual models representing intact and compromised cortical bone: Straumann (4.1-mm diameter x 12-mm length), AstraTech (4.0-mm diameter x 13-mm length), and 3i (3.75-mm diameter x 13-mm length). The compromised cortical bone condition was simulated by contaminating a 1-mm neck portion with Vaseline to impair the implant-resin interface. Vertical and oblique static loads were applied on the abutments, and the resulting stresses were monitored photoelastically and recorded photographically.


RESULTS
For the fully intact condition, the highest stresses were observed around the crest and apical region for all implant designs under vertical and inclined loads. There were no appreciable differences in magnitude or distribution between implant types. With compromised cortical bone, for all designs and load directions, higher stresses in the supporting structures were observed. Increased stresses were noted especially at the cortical bone-trabecular bone interface. Somewhat lower stress levels were observed with the 3i implant.


CONCLUSIONS
The condition of implant-cortical bone contact has considerable influence on stress distribution. A compromised cortical bone condition caused higher level stresses for all implant designs tested.
Akça
Kivanç
K
Department of Prosthodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. akcak@hacettepe.edu.tr
Fanuscu
Mete I
MI
Caputo
Angelo A
AA
D000134:Acid Etching, Dental; D000535:Aluminum; D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000503:physiopathology*; D000044:Dental Abutments; D045662:Dental Etching; D015921:Dental Implants; D017267:Dental Prosthesis Design; D055119:Elastic Modulus; D006801:Humans; D021621:Imaging, Three-Dimensional; D008422:Materials Testing; D008953:Models, Anatomic; D012826:Silicone Elastomers; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
D001672:Biocompatible Materials; D015921:Dental Implants; D012826:Silicone Elastomers; C009495:titanium dioxide; D000535:Aluminum; D014025:Titanium