Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
Angle Orthod. 2010 Nov;80(6):1051-60. doi: 10.2319/112409-665.1.
To evaluate the use of bone morphogenetic proteins to enhance postorthodontic stability in sheep and to develop a biological method of postorthodontic retention.
First incisors were extracted in four mature and healthy sheep, and the second incisors were tipped reciprocally toward the midline and then retained. Dried bone matrix was injected into the distal periodontal space of the left second incisor. The right second incisor was left as a control. Both incisors were retained in the tipped position for 4 weeks. Then, the orthodontic appliance was removed and the teeth were left without retention. Six weeks later, the animals were killed and serial sections were prepared for histologic observation.
Unlike the control, the experimental second incisor maintained its tipped position with minimal relapse. On the distal periodontal space of the experimental tooth, areas of focal fusion between newly formed bone and newly formed areas of hypercementosis were observed. In the distal periodontal space of the control tooth, osteoclastic activity was observed along most of the socket wall, and the periodontal space appeared narrow and compressed. This brought the tooth close to the boundary of the alveolar bone, confirming the relapse observed on that side.
This study proposes a new method of retention in which a biologically safe osteoinductive material is used to retain the teeth via induction of points of approximation between the cementum and alveolar bone.
评估骨形态发生蛋白在增强绵羊正畸后稳定性方面的应用,并开发一种正畸后保持的生物学方法。
在 4 只成熟健康的绵羊中拔除第一前磨牙,将第二前磨牙向中线反方向倾斜并保持。将干燥的骨基质注入左侧第二前磨牙的远牙周间隙。右侧第二前磨牙作为对照。将两颗切牙都保持在倾斜位置 4 周。然后,拆除正畸矫治器,牙齿不保持。6 周后,处死动物并制备连续切片进行组织学观察。
与对照组不同,实验组的第二前磨牙保持倾斜位置,复发最小。在实验牙的远牙周间隙中,观察到新形成的骨与新形成的过度牙骨质区域之间的局部融合区域。在对照组牙的远牙周间隙中,沿牙槽骨壁的大部分观察到破骨细胞活性,牙周间隙变窄且受压。这使得牙齿靠近牙槽骨边界,证实了在该侧观察到的复发。
本研究提出了一种新的保持方法,即使用生物安全的成骨诱导材料,通过诱导牙骨质和牙槽骨之间的接近点来保持牙齿。