Uysal Tancan, Olmez Huseyin, Amasyali Mihri, Karslioglu Yildirim, Yoldas Atilla, Gunhan Omer
Department of Orthodontics, Erciyes University, Kayseri, Turkey.
Aust Orthod J. 2010 May;26(1):49-55.
To determine the response of the expanded premaxillary suture in the rat to an externally applied force. Specifically, to investigate early bone changes in the expanded suture to intermittent loading and unloading.
Twenty-four 50 to 60 day-old Wistar rats were assigned to three groups. The inter-premaxillary sutures in all animals were expanded with a 50 g force applied to the upper incisors. Group I served as the control, whereas in Groups II and III the incisors were subjected to intermittent loading and unloading after five days of expansion. The intermittent forces were produced by a cam (0.416 mm, 100 cycles per minute) applied to the disto-gingival margins of the upper incisors. The mechanical stimuli were applied daily over nine days for six seconds in Group II (30 grams force, 10 cycles/day) and 10 minutes in Group III (30 grams force, 1000 cycles/day). Bone regeneration in the suture was evaluated histomorphometrically. The area of new bone (microm2), the perimeter around the new bone (microm), Feret's diameter (microm) and the percentage of new bone to non-ossified tissue (%) were measured and compared.
Statistically significant differences were found between the groups for all histomorphometric parameters. New bone area (p < 0.001), bone perimeter (p < 0.001), Feret's diameter (p < 0.001) and percentage of new bone (p < 0.001) were significantly larger in the experimental groups as compared with the Control group. The histomorphometric measurements confirmed that more new bone was deposited in the sutures subjected to intermittent loading and unloading.
The application of cyclic loading and unloading to the orthopaedically expanded inter-premaxillary suture during the early retention phase stimulated the formation of new bone.
确定大鼠上颌前部扩张缝对外加力的反应。具体而言，研究扩张缝对间歇性加载和卸载的早期骨变化。
将24只50至60日龄的Wistar大鼠分为三组。对所有动物的上颌间缝施加50 g力以扩张上切牙。第一组作为对照组，而在第二组和第三组中，在扩张五天后对上切牙进行间歇性加载和卸载。间歇性力由施加在上切牙远中龈缘的凸轮产生（0.416 mm，每分钟100次循环）。在第二组中，每天施加机械刺激9天，每次6秒（30克力，每天10次循环），在第三组中每天施加10分钟（30克力，每天1000次循环）。通过组织形态计量学评估缝中的骨再生。测量并比较新骨面积（平方微米）、新骨周围周长（微米）、费雷特直径（微米）以及新骨占非骨化组织的百分比（%）。
所有组织形态计量学参数在各组之间均存在统计学显著差异。与对照组相比，实验组的新骨面积（p < 0.001）、骨周长（p < 0.001）、费雷特直径（p < 0.001）和新骨百分比（p < 0.001）均显著更大。组织形态计量学测量证实，在经历间歇性加载和卸载的缝中沉积了更多新骨。
在早期保持阶段，对上颌前部经矫形扩张的缝施加周期性加载和卸载刺激了新骨的形成。
