Clinical investigation of causes of vertical root fracture in pulpless teeth;
无髓牙牙根纵裂原因分析
The results show that,all targets of the tension at break,elongation at break,percentage of elongation at break and scale degree of nonmedullar fibers of two experimental groups are much higher than those of comparative group (P<0.
The results showed that,all targets of stretched length,strength,degree of elasticity and sulphur content of nonmedullar fibers in those treatment groups were significantly higher or much higher than those of the other comparative groups (P<005 or P<001).