Comparison of color stability, mechanical and chemical properties according to temporary crown resin type / 대한치과재료학회지

Objective of this study was to compare the color stability, mechanical and chemical properties of three different types of temporary crown resins. Commercially available powder-liquid (Group PL), light-cured (Group LC) and auto-mix syringe (Group AM) types' temporary crown resins were used as experimental groups for each of the evaluation. All the test groups were evaluated after 1 day and 7 days of immersion in various staining solutions. The colors of all groups before and after storage in the staining solutions were measured by a spectrophotometer based on CIE Lab system, and the color differences (ΔE(*)) thereby calculated. Micro hardness test was performed before water storage and aging after 7 days at 37 ℃. In addition, flexural strength, water sorption and solubility tests were performed according to international standard, ISO 10477. All experimental groups showed significant color change in staining solutions when compared to those stored in the control solution (distilled water) (p PL > LC (p<0.05). Water sorption and solubility increased in the following order: AM < PL < LC (p<0.05). The results of this study would provide useful information when choosing temporary crown resin types in various clinical situations.

A study on the difference analysis between an ideal and a clinical shape in case of manufacturing a metal-ceramic pontic substructure

PURPOSE: The purpose of this research is to determine whether pontic metal substructures, which are currently used in clinical surgeries, are designed appropriately and identify the problems that can occur due to their shape, size, and position. Then it aimed to emphasize the importance of making and designing pontic metal substructures based on basic principles. MATERIALS AND METHODS: This research measured pontic basal surface (P1) used sample metal substructures in this study, gingiva margin (P2), and the porcelain thickness of maximum infrabulge of labial surface around 1/3 of cervix dentis (P3). One-way ANOVA analysis was carried out to test the differences among groups, Tukey Honestly Significant Difference Test was conducted for statistical analysis among groups. RESULTS: For porcelain thickness and SD value, the P1 part was 1.2 - 1.8 (±0.17) mm for experimental group 1, 1.2 - 1.7 (±0.17) mm for experimental group 2, and 0.4 - 2.8 (±0.92) mm for experimental group 3. Next, the P2 part was 1.4 - 1.6 (±0.07) mm for experimental group 1, 1.3 - 1.8 (±0.07) mm for experimental group 2, and 0.5 - 2.7 (±0.67) mm for experimental group 3. The P3 part was 1.4 - 1.7 (±0.10) mm for experimental group 1, 1.5 - 2 (±0.10) mm for experimental group 2, and 0.9 - 3.1 mm (±0.90) for experimental group 3. There was no significance when One-way ANOVA analysis/Tukey Honestly Significant Difference Test was conducted for statistical analysis among groups (P > 0.05). CONCLUSION: The suggested metal substructures can be used clinically as they meet the requirements that pontic must have.