Feichtinger Matthias, Mossböck Rudolf, Kärcher Hans
Department of Oral and Maxillofacial Surgery, Medical University of Graz, Graz, Austria.
Cleft Palate Craniofac J. 2007 Mar;44(2):142-8. doi: 10.1597/06-047.1.
Secondary bone grafting plays an important role in the dental rehabilitation of patients with clefts of the lip, alveolus, and palate. A major complication of this surgical technique is resorption of the grafted bone transplant. Conventional two-dimensional radiographs are often inconclusive and do not demonstrate the true deficit. The main objective of this study was to evaluate the amount and exact location of bone loss on the basis of three-dimensional models over a period of 3 years.
Twenty-four patients with unilateral cleft palate were included in this prospective study. Axial computed tomography scans of all patients were taken immediately preoperatively, and 1, 2, and 3 years postoperatively. Volumetric analysis was performed on three-dimensional models of the cleft defects and the bone bridges using three-dimensional computed tomography.
All patients were treated by secondary alveolar bone grafting prior to eruption of the permanent canine.
Extensive bone resorption was found in the bucco-palatal dimension of the alveolar portion of the transplant. The success rate of secondary bone grafting was high in cases of rapid orthodontic gap closures. The mean bone loss in the first year after surgery was 49.5%. The transplants remained almost constant in the following 2 years.
Radiographic scales based on orthopantomography only evaluate the vertical dimension of the transplants. This study, however, showed that bone resorption in the transversal dimension is clearly underestimated with conventional two-dimensional radiographs.
二期骨移植在唇、牙槽突及腭裂患者的牙列修复中起着重要作用。这种手术技术的一个主要并发症是移植骨块的吸收。传统的二维X线片往往难以得出结论，无法显示真正的骨量缺失情况。本研究的主要目的是基于三维模型评估3年期间骨量丢失的数量和确切位置。
本前瞻性研究纳入了24名单侧腭裂患者。所有患者在术前即刻、术后1年、2年和3年进行了轴向计算机断层扫描。使用三维计算机断层扫描对腭裂缺损和骨桥的三维模型进行容积分析。
所有患者在恒牙尖牙萌出前接受二期牙槽骨移植治疗。
在移植骨牙槽部分的颊腭径发现广泛的骨吸收。在正畸间隙快速关闭的病例中，二期骨移植的成功率较高。术后第一年的平均骨丢失率为49.5%。在接下来的2年中，移植骨量几乎保持不变。
基于曲面断层片的影像学标准仅评估移植骨的垂直径。然而，本研究表明，传统二维X线片明显低估了横向维度的骨吸收情况。
