Comparisons of dimensional accuracy and bending resistance among four kinds of super-hard plaster casts
10.3969/j.issn.1673-8225.2011.21.043
- VernacularTitle:四种超硬石膏模型精度及抗弯强度的比较
- Author:
Donghui LEI
;
Jianjun YANG
;
Shichang AN
;
Xiaofei LI
;
Tongxiao FU
;
Chunfang WANG
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2011;15(21):3979-3982
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND: In the clinic, super-hard plaster is widely used for preparation of casts that can duplicate oral cavity situation, such as fixed denture and removable denture. The bending resistance of super-hard plaster can sufficiently resist the force to strip, which would avoid the fracture of tooth model. However, the symptom of tooth model fracture exists when hard material, such as polyether rubber, is used as impression material. OBJECTIVE: To compare the dimensional accuracy and bending resistance among four kinds of super-hard plaster: YCG, Dentona, Heraeus, and Huicheng. METHODS: Mental casts including three unit fixed bridge and cuboid (50 mm×10 mm×5 mm) were prepared and then poured with the above-mentioned four kinds of super-hard plaster. Then dimensional accuracy and bending resistance of the casts were measured through the use of universal tool microscope and universal testing machine. CONCLUSION AND RESULTS: The proximal-distal dimensional accuracy of YCG, Dentona, Heraeus, and Huicheng super-hard plaster casts was 15.043, 15.034, 15.037 and 15.040 mm, respectively, the buccolingual dimensional accuracy was 7.020, 7.015, 7.019, and 7.019 mm, respectively, the tooth long-axis dimensional accuracy was 8.022, 8.018, 8.019, and 8.02 mm, respectively. The bending resistance of the four super-hard plaster casts was 15.687, 13.000, 22.521, 18.675 MPa, respectively. There was no significant difference in dimensional accuracy (P > 0.05), but there was significant difference in bending resistance (P < 0.01), among these four super-hard plaster casts. The bending resistance of Heraeus super-hard plaster cast was significantly greater compared with the other 3 super-hard plaster casts (P < 0.01), and the bending resistance of Huicheng super-hard plaster cast was significantly greater than that of Dentona super-hard plaster cast (P < 0.01). These findings demonstrate that Heraeus super-hard plaster has the highest bending resistance, followed by Huicheng and YCG super-hard plaster casts, and lastly Dentona super-hard plaster cast. These findings suggest that super-hard plaster cast with greater bending resistance should be chosen as possible according to practical situation.
