Department of Prosthodontics and Oral Rehabilitation, Osaka University Graduate School of Dentistry, Suita, Japan.
Clin Implant Dent Relat Res. 2012 May;14 Suppl 1:e183-7. doi: 10.1111/j.1708-8208.2011.00423.x. Epub 2011 Dec 16.
The poor bone quality that exists in the posterior maxilla is associated with lower initial stability and higher failure rates in implants. This study examined the bone densities of edentulous posterior maxillae by computed tomography (CT).
Based on CT images, the voxel values representing implant replacement in the posterior maxillary regions of 30 patients were calculated in the range from 150 to 2,000 Hounsfield units (HU). The bone densities of these regions were categorized according to Misch's classification and compared among individuals and between sexes.
The average of the median individual CT values was 495 HU (95% confidence interval: 442-547 HU) and was significantly higher in males than in females. Most of the bone in the posterior maxillae was classified as D3 (350-850 HU) or D4 (150-350 HU) according to Misch's classification, comprising 50% and 32% of the entire regions, respectively.
More than 80% of the edentulous posterior maxillae consisted of porous cortical crest or no cortical bone according to CT, although the bone densities varied markedly among individuals. More detailed assessments of bone density may be useful to enhance initial stability of implants in the posterior maxilla.
上颌后区骨质较差与种植体初始稳定性降低和失败率升高有关。本研究通过计算机断层扫描（CT）检查了无牙上颌后区的骨密度。
根据 CT 图像，计算了 30 名患者上颌后区种植体替代的体素值，范围为 150 至 2000 亨氏单位（HU）。根据 Misch 分类，对这些区域的骨密度进行分类，并在个体之间和性别之间进行比较。
中位数个体 CT 值的平均值为 495HU（95%置信区间：442-547HU），男性显著高于女性。根据 Misch 分类，上颌后区的大部分骨被归类为 D3（350-850HU）或 D4（150-350HU），分别占整个区域的 50%和 32%。
尽管个体之间骨密度差异显著，但根据 CT，超过 80%的无牙上颌后区由多孔皮质嵴或无皮质骨组成。更详细的骨密度评估可能有助于增强上颌后区种植体的初始稳定性。
