边缘形态与粘接剂对铸造金属全冠边缘适合性影响的析因分析

Factorial analysis of different finish lines and luting cements on marginal adaptation of cast full crowns

目的:评估边缘形态与粘接剂两种因素对全冠边缘适合性的影响,并探讨两种因素对全冠边缘适合性是否存在交互作用。方法:制作预备体长6mm、直径10mm、聚合度12°的树脂模型60个,按不同边缘形态随机平均分为2组,每组模型进而被随机平均分为3个小组。每一模型进行四点标记,常规制作钴铬金属全冠,按标记点就位。边缘形态(因素A)选取2种:A1为凹面肩台,A2为直角肩台;粘接剂(因素B)选取3种:B1为聚羧酸锌水门汀粘接剂(ZPCC),B2为CX玻璃离子水门汀粘接剂(GIC),B3为RelyXUnicem树脂水门汀粘接剂(RC)。按照A1B1、A1B2、A1B3、A2B1、A2B2、A2B3分别对6组金属全冠进行粘接处理,每个金属全冠均采用10kg载荷加压至粘接剂完全固化。每个金属全冠在代型上粘接前后分别用SMZ745T体视显微镜于四个标志点处对边缘终止线到冠边缘外侧之间的垂直边缘缝隙进行拍照,用Image-ProPlus6.0软件系统进行测量,计算粘接前后冠边缘缝隙的浮升量,采用SPSS13.0软件进行两因素方差分析。结果:粘接后A1B1、A1B2、A1B3、A2B1、A2B2、A2B3六组边缘浮升量分别为(64.84±35.62)、(47.47±28.27)、(107.78±56.91)、(69.68±39.44)、(58.44±38.39)、(131.90±66.18)μm。A1B2组边缘浮升量变化最小,A2B3组最大。边缘形态不变时,应用不同粘接剂粘接时的样本浮升量两两之间比较有统计学意义(P<0.05);应用同一种粘接剂时,不同边缘形态的样本浮升量之间比较无统计学意义(P>0.05)。边缘形态和粘接剂两种因素同时作用时对边缘适合性的影响有统计学意义(P<0.05)。结论:考虑到边缘适合性,边缘形态与粘接剂相互之间对边缘适合性的影响存在交互作用。临床上铸造金属全冠修复时,建议选择凹面肩台并选用CX玻璃离子水门汀粘接剂粘接。

Objective： To evaluate the marginal adaptation of cast full crowns fabricated with two different finish lines and cemented with three luting cements and the interaction effect of two factors on marginal adaptation of cast full crowns.Methods： Sixty resin models with a preparation height of 6mm, a diameter of 10 mm and a total convergence angle of 12 degrees were made and randomly divided into two groups according to their finish lines. And the models in each group were randomly subdivided into three groups on average. Wax patterns for full crowns were fabricated by a traditional method. Four symbol sites were made in every pattern. All the wax patterns were invested and cast routinely. The finished full crowns were seated on the preparations according to their symbol sites.The finish line factor（A） included A1： chamferand A2： shoulder. The cement factor（B） included B1： zinc polycarboxylate cement（ZPCC）, B2： CX glass ionomer cement（GIC） and B3： Rely X Unicem resin cement（RC）. The specimens received treatments according to the groups of A1B1, A1B2, A1B3, A2B1, A2B2 and A2B3, respectively. A 10 kg load wasmaintained on the crowns until their complete cement cure. Their vertical marginal gaps were photographed at the four points around each crown by SMZ745 T optical stereomicroscope before and after cem entation, respectively, and measured using Image-Pro Plus 6.0. The data were analyzed by two-way ANOVA using SPSS13.0 software. Results： The marginal discrepancies after cementation were as follows： A1B1）（64.84 ±35.62） μm, A1B2）（47.47 ±28.27） μm, A1B3）（107.78 ±56.91） μm, A2B1）（69.68 ±39.44） μm,A2B2）（58.44 ±38.39） μm and A2B3）（131.90 ±66.18） μm. The minimum discrepancy was in the group A1B2 and the maximum in the group A2B3.Despite of different finish lines, there were significant differences among different cements.When using the same cement, there were no significant differences among different finish line groups. Under the effects of finish line combined with luting cement, there was statistic difference. Conclusion： The effect of finish line and luting cement on marginal adaptation is interactive. For cast full crown restoration, the chamfer combined with GIC should be a better choice.