Effects of implant thread geometry on percentage of osseointegration and resistance to reverse torque in the tibia of rabbits.
BACKGROUND
Dental implant thread geometry has been proposed as a potential factor affecting implant stability and the percentage of osseointegration. Therefore, the aim of this prospective, randomized, parallel arm study was to evaluate the effects of dental implant thread design on the quality and percent of osseointegration and resistance to reverse torque in the tibia of rabbits.


METHODS
Seventy-two custom-made, screw-shaped, commercially pure titanium implants (3.25 mm diameter x 7 mm length) were placed in the tibiae of 12 white New Zealand rabbits. Each tibia received three implants of varying thread shapes: one with a V-shaped, one with a reverse buttress, and one with a square thread design. The rabbits were sacrificed following an uneventful healing period of 12 weeks. Implants in the right tibiae underwent histologic and histomorphometric assessments of the bone-to-implant contact (BIC) and the radiographic density of surrounding bone, while implants in the left tibiae were used for reverse-torque testing. Differences between the three thread designs were examined using analysis of variance (ANOVA).


RESULTS
Data showed that the square thread design implants had significantly more BIC and greater reverse-torque measurements compared to the V-shaped and reverse buttress thread designs, while no differences were found in radiographic bone density assessments.


CONCLUSIONS
These results indicate that the square thread design may be more effective for use in endosseous dental implant systems.
Steigenga
Jennifer
J
Department of Periodontology/Prevention/Geriatrics, School of Dentistry, University of Michigan, Ann Arbor, Ml 48109-1078, USA.
Al-Shammari
Khalaf
K
Misch
Carl
C
Nociti
Francisco H
FH
Wang
Hom-Lay
HL
D000704:Analysis of Variance; D000818:Animals; D015519:Bone Density / Q000502:physiology; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D016348:Osseointegration / Q000502:physiology*; D011817:Rabbits; D011897:Random Allocation; D013314:Stress, Mechanical; D013977:Tibia / Q000473:pathology / Q000502:physiology* / Q000601:surgery; D014025:Titanium / Q000737:chemistry; D019415:Torque; D014945:Wound Healing / Q000502:physiology
D015921:Dental Implants; D014025:Titanium