Effect of Implant Thread Geometry on Secondary Stability, Bone Density, and Bone-to-Implant Contact: A Biomechanical and Histological Analysis.
OBJECTIVE
This study evaluated the effect of 2 different thread designs on secondary stability (micromotion) and osseointegration rate in dense and cancellous bones.


METHODS
Forty large threaded and 40 small threaded implants (Cortex) were placed in low- (iliac crest) and high-density (mandible) bone of sheep. Two months later, micromobility tests and histological analysis were performed to measure secondary stability, osseointegration (bone-to-implant contact percentage [%BIC]), and bone density (bone volume percentage [%BV]). The value of actual micromotion of implant is introduced as a new parameter to evaluate secondary stability.


RESULTS
Large threaded implants showed significantly higher %BIC and %BV than small threaded implants in low-density bone and statistically higher secondary stability in cancellous and cortical bones.


CONCLUSIONS
Implants in dense bone reach higher secondary stability than those in cancellous bone, despite the lower %BIC. Implant geometry and bone density play a key role in secondary stability. Large thread design improves bone anchorage mechanically and histologically as compared with small threaded implants.
*Scientific Director, Biomaterial Clinical Research Association; Private Practice, Pescara, Italy. †Biomaterial Clinical Research Association, Pescara, Italy; Private Practice, Pescara, Italy. ‡"G. Caporale" Institute, Teramo, Italy.
Paolo
P
Trisi
Marco
M
Berardini
Antonello
A
Falco
Michele
M
Podaliri Vulpiani
D000818:Animals; D015519:Bone Density / Q000502:physiology*; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D005260:Female; D008334:Mandible / Q000601:surgery; D016348:Osseointegration / Q000502:physiology*; D012756:Sheep; D013499:Surface Properties
D015921:Dental Implants