Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
Clin Implant Dent Relat Res. 2012 May;14 Suppl 1:e213-23. doi: 10.1111/j.1708-8208.2012.00441.x. Epub 2012 Feb 29.
Healthy, well-structured mucosa may clinically disguise atrophic jawbone in preimplant diagnosis.
To analyze bone width in relation to the complete ridge thickness comparing the anterior with the posterior edentulous maxilla.
Data of 52 patients (mean age 62 ± 9 years) who were edentulous for at least 1 year and who received implant treatment were analyzed. Computed tomography (CT) scans were obtained and virtually analyzed in perpendicular sections of 12 maxillary positions (central and lateral incisors, canines, premolars, and first molars) using an implant planning software. Absolute thickness of complete jaw, bone, and mucosa were digitally measured at crestal and basal ridge levels allowing for relative bone width (B-rel) calculation.
Mean B-rel at crestal levels was lower than at basal levels (38.6% vs 51.5%, p < .001). Bone width increased significantly (p < .001) in the posterior maxilla at both levels, whereas the thickness of palatal and buccal mucosa was considerably stable. Mean basal B-rel ranged from 49% (6.2 ± 2.0 mm) at incisors to 59% (9.0 ± 2.3 mm) at first molars (p < .001). Mean proportion of regions showing B-rel < 50% were 43% at basal and 80% at crestal levels.
The osseous volume of a large edentulous ridge might be clinically overestimated in preimplant diagnosis, as the relative bone width was generally lower than 50%. Clinicians can use the present results of the virtual bone and mucosa measurements to have a better first estimation of the osseous proportion depending on the maxillary area. However, up to date implant therapy for the edentulous maxilla requires CT-based prosthetically driven implant planning and preferably combination with guided implant placement by transferring planning information to a surgical template.
健康且结构良好的黏膜可能会在种植前诊断中掩盖萎缩的颌骨。
分析牙槽嵴完整厚度与牙槽骨宽度的关系，比较上颌无牙颌前牙区和后牙区。
分析了 52 名（平均年龄 62 ± 9 岁）至少 1 年无牙并接受种植治疗的患者的数据。获得了计算机断层扫描（CT）扫描，并使用种植体规划软件在 12 个上颌位置（中切牙和侧切牙、尖牙、前磨牙和第一磨牙）的垂直切片中进行了虚拟分析。在牙槽嵴和基底嵴水平上对完整牙槽骨、骨和黏膜的绝对厚度进行了数字化测量，允许计算相对骨宽度（B-rel）。
牙槽嵴水平的平均 B-rel 低于基底水平（38.6%对 51.5%，p <.001）。在两个水平上，上颌后牙区的骨宽度均显著增加（p <.001），而腭侧和颊侧黏膜的厚度相对稳定。基底 B-rel 的平均值范围从切牙的 49%（6.2 ± 2.0 mm）到第一磨牙的 59%（9.0 ± 2.3 mm）（p <.001）。在基底水平和牙槽嵴水平上，B-rel < 50%的区域比例分别为 43%和 80%。
在种植前诊断中，大的无牙颌嵴的骨量可能会被临床高估，因为相对骨宽度一般低于 50%。临床医生可以使用虚拟骨和黏膜测量的现有结果，根据上颌区域对骨比例进行更好的初步估计。然而，目前上颌无牙颌的种植治疗需要基于 CT 的基于假体的种植体规划，最好结合通过将规划信息转移到手术模板来引导种植体放置。
