[Biomechanical comparison of self-drilling and self-tapping orthodontic micro-implants].
OBJECTIVE
To evaluate the biomechanical influences of self-drilling and self-tapping methods on orthodontic micro-implants under immediate loading.


METHODS
Fifty-six micro-implants placed at the interradicular areas of buccal side of upper and lower jaws in two dogs were divided into self-drilling and self-tapping groups. A horizontal load of 1.96 N was immediately given for 9 weeks. Peak insertion torque and peak removal torque were tested immediately after implantation and after the dogs were killed, respectively.


RESULTS
Both in the upper and lower jaws peak insertion torque was significantly higher in self-drilling group [(5.6 +/- 1.1) N.cm and (8.7 +/- 2.3) N.cm] than in self-tapping group [(3.5 +/- 2.1) N.cm and (7.4 +/- 1.1) N.cm] (P < 0.05). Both in the upper and lower jaws peak removal torque was higher in self-drilling group [(-6.5 +/- 2.2) N.cm and (-7.1 +/- 2.0) N.cm] than in self-tapping group [(-5.7 +/- 2.3) N.cm and (-6.1 +/- 0.5) N.cm]. No significant difference was found (P > 0.05). The tendency of fracture was found in self-drilling group.


CONCLUSIONS
Self-drilling micro-implants have high initial stability and can be used in the maxilla and at thin cortical bone area of mandible.
Chen
Yan
Y
Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu 700-412, Korea.
Zhao
Wen-ting
WT
Kyung
Hee-moon
HM
D000818:Animals; D001696:Biomechanical Phenomena; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D003799:Dental Stress Analysis; D004285:Dogs; D005260:Female; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D019415:Torque
D015921:Dental Implants