不同灌注间隔时间对模型材料间结合强度的影响

Effect of pouring interval on bonding strength between model materials

目的研究分步灌模时不同灌注间隔时间对模型材料间结合强度的影响。方法超硬石膏和硬石膏灌注印模腔一侧,间隔试验设定时间后用普通石膏灌注另一侧,按间隔时间分为0 min组、5 min组、10min组、20 min组、30 min组和60 min组,每组样本10个,共120个。测量各试样拉伸强度,用单因素方差分析和L-S-D法进行比较。结果超硬石膏5 min组拉伸强度最大,为(1.40±0.24)MPa;硬石膏组内最大拉伸强度为0 min组,(1.11±0.11)MPa。两组试样拉伸强度均随间隔时间延长而下降,组间有高度统计学差别(P<0.01)。结论在超硬石膏或硬石膏灌注完成后应立即灌注普通石膏,或至少在10 min以内灌注。

Objective To evaluate whether different pouring intervals affect the bonding strength between different model materials.Methods We poured superstones or dental stones into one side of the impression,then gypsum into the other side gypsum after different interval time-0min,5min,10min,20min,30min and 60 min.Each group contained 10 samples and the total was 120.The tensile strength of each sample was measured by a universal test machine.The data were analyzed with ANOVA and L-S-D method.Result Among the superstones groups,the 5 min group got the biggest tensile strength(1.40±0.24 MPa).And the 0 min group was the best among the stone groups(1.11±0.11 MPa).The bonding strength between different model materials was affected by pouring interval.Conclusion When making dental models by step,we should pour gypsum right after the pouring of superstones or dental stone,or within 10 minutes at least.