Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
Department of Radiology, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
Clin Implant Dent Relat Res. 2019 Oct;21(5):1041-1047. doi: 10.1111/cid.12829. Epub 2019 Aug 1.
Bone tissues may undergo remodeling under functional mechanical stimuli.
This prospective study on implant-supported fixed complete dentures (IFCDs) evaluated the radiographic trabecular bone changes in density by means of gray levels and texture analysis variables after up to 3-year loading.
The sample consisted of digital periapical radiographs of 63 distal implants of hybrid IFCDs installed in 30 patients (22 women, mean age of 62 ± 7.8 years). Digital periapical radiographs were taken after prosthesis installation, and 1 and 3 years after IFCD loading. Longitudinal images of each implant were superimposed, and the same regions of interest were selected for measurement of gray levels statistics (mean gray levels, SD, and coefficient of variation [CV]) and texture parameters (correlation, contrast, entropy, and angular second moment). Data were analyzed by mixed regression models.
Mean gray levels increased for 1 year (P < .05), for 3 years (P < .01) and for maximum bite force (P < .01). The interaction between bruxism and time in 1 year was significant (P < .01) for a decrease in CV. No significant effect of texture analysis variables was found (P > .05).
The results suggest an increase of radiographic bone density as measured by an increase in mean gray levels and a decrease in CV in IFCD distal implants up to 3 years of loading.
骨骼组织在功能性机械刺激下可能会发生重塑。
本前瞻性研究对种植体支持的固定全口义齿（IFCD）进行了研究，通过灰度和纹理分析变量评估了长达 3 年负荷后骨小梁骨密度的放射性变化。
该样本由 30 名患者（22 名女性，平均年龄 62±7.8 岁）的 63 个混合 IFCD 远侧种植体的数字根尖片组成。在义齿安装后、IFCD 加载后 1 年和 3 年拍摄数字根尖片。对每个种植体的纵向图像进行叠加，并选择相同的感兴趣区域进行灰度水平统计（平均灰度水平、标准差和变异系数 [CV]）和纹理参数（相关性、对比度、熵和角二阶矩）的测量。数据分析采用混合回归模型。
平均灰度水平在 1 年时增加（P<.05），在 3 年时增加（P<.01），在最大咬合力时增加（P<.01）。1 年内磨牙症与时间的交互作用有统计学意义（P<.01），CV 降低。纹理分析变量无显著影响（P>.05）。
结果表明，在种植体支持的固定全口义齿远侧种植体中，平均灰度水平增加和 CV 降低表明放射性骨密度增加，负荷可达 3 年。
