不同熔模材对冠边缘精度影响的研究

Comparison of the casting crown with different pattern materials.

目的:研究四种不同材料熔模在完成后不同时间边缘浮升量的变化及对铸造冠边缘精度的影响。方法:用统一标准模具翻制40个超硬石膏代型,随机分为四组,每组10个,分别采用日进公司的Casting Pattern Resin,松风Hard嵌体蜡、BEGO牙冠蜡和国产嵌体蜡(分别简称日进、松风、BEGO和国产),于实验室内在石膏代型上分别制作10个熔模,熔模完成10、20、30、60、120、240 min时,在投影测量仪下测量熔模边缘的浮升量,并于熔模完成30 min后采用同一种方法包埋、铸造,比较铸造冠边缘的浮升量。结果:①在10～30 min,各种熔模的边缘浮升量逐渐变大,各时间点间有高度差异性(P<0.01);30～240 min,各种熔模的浮升量变化不明显,各时间点间无差异性(P>0.05)。②在各时间点,日进熔模的边缘浮升量最小,国产熔模的浮升量最大,松风和BEGO熔模居中,四种熔模间有差异性(P<0.05)。③日进熔模制成的铸造冠的边缘浮升量最小,国产熔模铸造冠的浮升量最大,松风和BEGO铸造冠居中,四种熔模铸造冠间有差异性(P<0.05)。结论:不同种类的熔模材对熔模精度的影响不同,在本试验中,日进熔模的边缘精度最高;熔模完成后在10 min时精度最高,30 min后对精度的影响较小;日进熔模制成的铸造冠的边缘精密性最高。

Objective：To evaluate the influence of different pattern materials on the marginal precision of wax pattern at different time and marginal precision of casting crown made with different pattern.Method：Standard specimens simulating post tooth crown were made.4 groups patterns were completed on the plaster dies replicated by standard specimens with four kinds of pattern material,Casting Pattern Resin,SOFU Hard wax,BEGO Crown wax and inlay wax.There were 10 pattern crowns in every group.The marginal opening of the pattern was measured under Projection Measuring Instrument at the time of 10,20,30,60,120,240 minutes.And the marginal opening of casting crown was also measured The data were statistically analyzed using one-way ANOVA at a significance level of 0.05.Result：①There was significant difference among 10,20,30 minutes and other time in every groups（P 0.01）;there was no significant between 30 minutes and the remains（P 0.05）.②The lowest marginal opening was obtained for Casting Pattern Resin,while inlay wax produced the highest marginal opening at every period.there was significant difference between the four groups at every periods（P 0.01）.③The same as the cast crown as the pattern were obtained.Conclusion：Within the limitations of this study,precision of pattern was affected by the type of pattern material used and the different periods of time.And Casting Pattern Resin was the best material for pattern and castings.