三种包埋材料对全口义齿蜡型形变大小的影响

The effect of three different investing materials on complete denture flasking deformation

目的 研究不同包埋材料对全口义齿蜡型包埋前后的形变影响.方法 采用普通石膏、超硬石膏、超硬石膏＋硅橡胶三种不同包埋材料,分别包埋下颌全口义齿蜡型,按随机数字表法分三组,各8个.采用金属型盒包埋及传统水浴加热,测量四个标记点在包埋前蜡型上及热处理后甲基丙烯酸酯树脂基托上的标记点间距离并观察义齿表面光滑度.结果 普通石膏组对标记点形变量的改变最大,平均值在175～267μm,超硬石膏组与硬膏硅胶组标记点形改变量接近,AB间距离（F=3.768,P=0.040）及总均数（F=4.830,P=0.019）的改变量在三种材料间差异有统计学意义,两两比较显示,普通石膏组AB间距离及总均数的改变量均大于超硬石膏组和硬膏硅胶组,但超硬石膏组与硬膏硅胶组间差异均无统计学意义.三组间光滑度差异有统计学意义（Х^2=17.575,P＜0.01）,硬膏硅胶组的光滑度最好.结论 普通白石膏组在包埋形变上最大且表面光滑度最差,超硬石膏组包埋的形变最小,而超硬石膏＋技工用硅橡胶联合包埋组的形变与单纯超硬石膏包埋组接近且表面光滑度最好.

Objective To investigate the effect of different investing materials on the complete denture flasking deformation.Methods The denture wax casts were invested by plaster,dental stone,and dental stone together with silicone,respectively.8 trial dentures were randomly chosen from above each group,and 4 reference points were selected in the cast.The conventional water bath polymerization system was used for the process.The distance between reference points were measured before and after thermally processing the Acrylic base.F test and Kruskal-Wallis H test were applied for statistical analysis.Results The distance between A and B （F =3.768,P =0.040） and the mean of total distance among O,A,B and C（F =4.830,P =0.019） had statistically significant differences among the three groups.The deformation variance of Group 1 （a conventional plaster） between 175μm and 267μm was maximum.The deformation values of Group2 （a dental stone） was appropriate with Group3 （a dental stone ＋ a silicone）.Smoothness （Х^2 =17.575,P 〈 0.01） was statistically different among the three groups.Conclusion The flaskingprocess with the plaster had the maximum movement.The process with dental stone showed the minimal toothmovement,the process with the dental stone along with with thesilicone caused a similar movement as from the single dental stone but resulted in a smoother denture surface.