目的: 评价可摘局部义齿(removable partial denture, RPD)适合性的三种方法的异同及适应证。方法: 在下颌牙列缺损石膏模型上制作RPD,用硅橡胶印模材复制RPD与模型表面的间隙形成硅橡胶薄膜样本。在RPD各组件处的薄膜样本上,用硅橡胶膜切片测量法并选择不同数量的测量点测量获得薄膜平均厚度,再用单因素方差分析和独立样本t检验比较基托、大连接体、牙合支托处测量点数量不同对测量结果的影响。采用硅橡胶膜切片测量法、石膏模型三维分析法和翻制模型三维分析法测量RPD各组件处硅橡胶薄膜的厚度,用单因素方差分析比较三种方法的测量结果差异是否有统计学意义。结果: 硅橡胶膜切片测量法选取测量点数量不同测得的基托和大连接体处硅橡胶薄膜的平均厚度差异有统计学意义(P<0.05),牙合支托处硅橡胶薄膜的平均厚度差异无统计学意义(P>0.05)。三种评价方法测得的RPD各组件和总体的硅橡胶薄膜厚度差异均有统计学意义(P<0.01),多重比较表明,石膏模型三维分析法和翻制模型三维分析法的测量结果较硅橡胶膜切片测量法的薄(P<0.05),石膏模型三维分析法和翻制模型三维分析法测量的硅橡胶薄膜厚度差异无统计学意义(P>0.05)。结论: 硅橡胶膜切片测量法的测量结果受测量点数量影响,其测量结果可靠性较差;石膏模型三维分析法、翻制模型三维分析法较硅橡胶膜切片测量法能更全面、有效地评价RPD的适合性,石膏模型三维分析法适用于体外评价,翻制模型三维分析法适用于体内评价。

Objective: To compare the differences and indications of three evaluation methods for fitness evaluation of removable partial denture (RPD). Methods: A RPD was fabricated and seated on the stone cast of a partially edentulous mandible, and the spaces between RPD and stone cast were recorded with polyvinyl siloxane (PVS) impression material forming PVS replicas. Using cross sectional measurement, the average thicknesses of PVS replicas were measured under stereomicroscope with different numbers of selected measuring points in the denture base, major connector, occlusal rest of the RPD, and the average thicknesses of the PVS replicas measured with different numbers of measuring points were compared using one-way analysis of variance (ANOVA) and independent sample t test. Three kinds of method, including cross sectional measurement, three-dimensional analysis on the stone cast, and three-dimensional analysis on the polyether cast, were applied to measure the average thicknesses of the PVS replicas, and the average thicknesses of the PVS replicas measured by these three evaluation methods were compared with ANOVA. Results: For cross sectional measurement, statistically significant differences were found in the average thicknesses of the PVS replicas in the denture base and the major connector among the different numbers of measuring points (P<0.05), but no differences were found in the average thicknesses of the PVS replicas in the occlusal rest (P>0.05). There were significant differences among the average thicknesses of the PVS replicas measured by these three evaluation methods in each component of the RPD (P<0.01). The average thickness measured by three-dimensional analysis on the stone cast and three-dimensional analysis on polyether cast were smaller than that measured by cross sectional measurement (P<0.05). And there were no differences between the average thicknesses of PVS replicas measured by three-dimensional analysis on stone cast and three-dimensional analysis on polyether cast (P>0.05). Conclusion: For cross sectional measurement, the average thickness of the PVS replicas was influenced by the number of measuring points, and the measurement accuracy of cross sectional measurement was not reliable enough. Three-dimensional analysis on stone cast which is suitable for evaluation in vitro and three-dimensional analysis on polyether cast which is suitable for evaluation in vivo can evaluate the fitness of RPD more comprehensively and effectively than that of cross sectional measurement.