不同微型种植体稳定性比较的动物实验

目的评价自攻型和助攻型正畸微型种植体的稳定性，探讨两种种植体生物力学的差别。方法将自攻型组与助攻型组正畸微型种植体（每组各28枚）种植于两只狗的上下颌骨颊侧根间区，植入时测量最高植入转矩，即刻负载水平力约1．96N，持续9周后取出种植体，测量最高去除转矩。结果上、下颌自攻型组最高植入转矩分别为（5．6±1．1）N·cm和（8．7±2．3）N·cm]均明显高于助攻型组分别为（3．5±2．1）N·cm和（7．4±1．1）N·cm]，差异均有统计学意义（P〈0．05）。上、下颌自攻型组最高去除转矩分别为（-6．5±2．2）N·cm和（-7．1±2．0）N·cm]均高于助攻型组分别为（-5．7±2．3）N·cm和（-6．1±0．5）N·cm]，差异均无统计学意义（P〉0．05）。自攻型组成功率为92．9％，助攻型组成功率为86．7％。结论自攻型种植体有较高的初期稳定性，适于种植在上颌骨及下颌骨骨皮质较薄的部位。

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.