Evaluation of physical properties of polycarbonate temporary restoration materials

Purpose@#The purpose is to test and evaluate the physical properties of commonly used temporary restoration materials and newly emerged materials. @*Materials and Methods@#Four groups of polymer materials were evaluated: Polymethyl methacrylate (PMMA) 2 groups, Polyetheretherketone (PEEK), Polycarbonate. Four physical properties were tested: surface hardness, bending strength, abrasion resistance during wear, wear behavior. The 3-axis bending strength and Vickers hardness test were measured using a universal testing machines respectively. The microstructure was observed with a scanning electron microscope and weight comparison was evaluated after 100,000 chewing tests using a chewing simulator. Kruskal wallis test was performed to evaluate statistical significance. @*Results@#The four groups showed the highest flexural strength and Vickers hardness of PEEK, followed by PC, PMMA-H, PMMA-T. Microstructure observation also showed the least surface roughness in the PEEK group, followed by PC, PMMA-H, PMMA-T. @*Conclusion@#PC is considered to have sufficient mechanical properties that can be applied to the manufacture of temporary teeth. However, further studies, such as biocompatibility, are considered to be necessary for practical clinical applications.

Evaluation of physical properties of polycarbonate temporary restoration materials

Purpose@#The purpose is to test and evaluate the physical properties of commonly used temporary restoration materials and newly emerged materials. @*Materials and Methods@#Four groups of polymer materials were evaluated: Polymethyl methacrylate (PMMA) 2 groups, Polyetheretherketone (PEEK), Polycarbonate. Four physical properties were tested: surface hardness, bending strength, abrasion resistance during wear, wear behavior. The 3-axis bending strength and Vickers hardness test were measured using a universal testing machines respectively. The microstructure was observed with a scanning electron microscope and weight comparison was evaluated after 100,000 chewing tests using a chewing simulator. Kruskal wallis test was performed to evaluate statistical significance. @*Results@#The four groups showed the highest flexural strength and Vickers hardness of PEEK, followed by PC, PMMA-H, PMMA-T. Microstructure observation also showed the least surface roughness in the PEEK group, followed by PC, PMMA-H, PMMA-T. @*Conclusion@#PC is considered to have sufficient mechanical properties that can be applied to the manufacture of temporary teeth. However, further studies, such as biocompatibility, are considered to be necessary for practical clinical applications.

Complete denture artificial teeth arrangement deformation in wax denture after festooning: deformation over time

PURPOSE: The purpose of this study was to evaluate the deformation of the complete denture artificial teeth arrangement after festooning over time. MATERIALS AND METHODS: 10 wax dentures of equal teeth arrangement and equal gingival contour were used in this study. Festooning of the wax dentures were conducted and 3D model scans were conducted every 10 minutes for 120 minutes. Interdental transverse distances were measured with the scanned images. Statistical analyses were performed with SPSS Ver. 22. 0. RESULTS: Interdental transverse distance between teeth varied from 0.0999 mm to 0.1787 mm. Mean rate of deformation showed statistically significant change between the 40 – 50 minute interval and 50 – 60 minute interval and between the 50 – 60 minute interval and 60 – 70 minute interval. No statistically significant change of the mean rate of deformation was observed later on. CONCLUSION: Monitoring of the interdental transverse distance for 120 minute after festooning have shown the deformation and displacment of the artificial teeth arrangement. From after the 60 – 70 minute interval after festooning, the mean deformation showed no statistically significant change of the mean rate of deformation was observed. Within the limitations of this in vitro study results suggest that the final occlusal adjustment in wax denture before complete denture curing should be proceeded at least 60 minutes later after festooning.

Artificial teeth displacement of monolithic complete denture manufactured by 3D printer and milling machine / 대한치과보철학회지

PURPOSE: The purpose of this study is to evaluate the displacement of artificial tooth of monolithic complete denture manufactured by milling and 3D printing method in which the denture base and the artificial teeth are simultaneously made. MATERIALS AND METHODS: Twelve upper and lower complete dentures for each were made by milling and 3D printing method. Group Up and Group Lp are a group of upper and lower dentures made by printing, and Group Um and Group Lm are denture groups made by milling. Group Uc and Group Lc are is a group of finally designed upper and lower dentures respectively. Measurements were performed between both central incisors (AB, ab), both canines (CD, cd), both first molars (EF, ef), between an incisor and a first molar (AE, ae), and between incisor and lingual point (AG, ag) for each upper and lower denture. RESULTS: AG and ag value between printed dentures and original ones as well as between milled dentures and original ones showed a statistically significant difference (One-way ANOVA, P<.05) in both lower and upper monolithic dentures. In the lower monolithic ones, ab, cd and ef value revealed a significant difference between Group Lp and Group Lm (One-way ANOVA, P<.05). CONCLUSION: Dentures made using milling or 3D printers revealed statistically significant difference compared with those of original data. However, it showed clinically very accurate reproducibility.