Keles Ahmet, Grunes Brandon, Difuria Catherine, Gagari Eleni, Srinivasan Vasanth, Darendeliler Mehmet A, Muller Ralph, Kent Ralph, Stashenko Philip
Department of Cytokine Biology, The Forsyth Institute, Boston, MA 02115, USA.
Eur J Oral Sci. 2007 Apr;115(2):131-6. doi: 10.1111/j.1600-0722.2007.00433.x.
The undesired movement of anchor teeth, and relapse of previously moved teeth, are major clinical problems in orthodontics. Dental implants are increasingly used to preserve anchorage, but these are costly and require invasive surgical procedures. An alternative strategy for maintaining anchorage may be the use of biological inhibitors of osteoclastic bone resorption. In the present study, we investigated the relative efficacy of pamidronate vs. osteoprotegerin (OPG) in inhibiting bone resorption and tooth movement, using a new orthodontic model in mice in which maxillary molars are moved for prolonged periods by near-constant, clinically relevant forces. Osteoclast influx to compression sites was initiated on day 3, was maximal on day 4, and persisted until at least day 12 after force application. Tooth movement paralleled osteoclast numbers. Minimal osteoclast apoptosis was observed, suggesting that recruitment, rather than programmed cell death, is a critical regulatory mechanism under conditions of constant force. Osteoclasts were reduced at compression sites by both OPG (95%) and pamidronate (70%); tooth movement was more dramatically inhibited by OPG (77% vs. 34%). Our findings indicate that constant orthodontic force regulates the recruitment, activation, and viability of osteoclasts, and that OPG could have clinical utility in preventing undesired tooth movement.
正畸治疗中，支抗牙的非预期移动以及先前移动牙齿的复发是主要的临床问题。牙种植体越来越多地用于保持支抗，但这些成本高昂且需要侵入性外科手术。维持支抗的另一种策略可能是使用破骨细胞性骨吸收的生物抑制剂。在本研究中，我们使用一种新的小鼠正畸模型，其中上颌磨牙通过接近恒定的、临床相关的力长时间移动，研究了帕米膦酸盐与骨保护素（OPG）在抑制骨吸收和牙齿移动方面的相对疗效。破骨细胞流入压缩部位在第3天开始，在第4天达到最大值，并持续到施力后至少第12天。牙齿移动与破骨细胞数量平行。观察到破骨细胞凋亡极少，这表明在恒力条件下，募集而非程序性细胞死亡是关键的调节机制。OPG（95%）和帕米膦酸盐（70%）均使压缩部位的破骨细胞减少；OPG对牙齿移动的抑制作用更为显著（77%对34%）。我们的研究结果表明，持续的正畸力调节破骨细胞的募集、激活和存活，并且OPG在预防非预期牙齿移动方面可能具有临床应用价值。
