Flexural strength of implant fixed prosthesis using fiber reinforced composite / 대한치과보철학회지

STATEMENT OF PROBLEM: Use of fiber composite technology as well as development of nonmetal implant prosthesis solved many problems due to metal alloy substructure such as corrosion, toxicity, difficult casting, expensiveness and esthetic limit. After clinical and laboratory test, we could find out that fiber-reinforced composite prostheses have good mechanical properties and FRC can make metal-free implant prostheses successful. PURPOSE: The purpose of this study is to evaluate the flexural strength of implant fixed prosthesis using fiber reinforced composite. MATERIAL AND METHODS: 2-implant fixture were placed in second premolar and second molar area in edentulous mandibular model, and their abutments were placed, and bridge prostheses using gold, PFG, Tescera, and Targis Vectris were fabricated. Tescera was made in 5 different designs with different supplements. Group I was composed by 3 bars with diameter 1.0mm and 5 meshes, 2 bars and 5 meshes for Group II, 1 bar and 5 meshes for Group III, and only 5 meshes were used for Group IV. And Group V is composed by only 3 bars. Resin (Tescera) facing was made to buccal part of pontic of gold bridge. All of gold and PFG bridges were made on one model, 5 Targis Vectris bridges were also made on one model, and 25 Tescera bridges were made on 3 models. Each bridge was attached to the test model by temporary cement and shallow depression was formed near central fossa of the bridge pontic to let 5 mm metal ball not move. Flexual strength was marked in graph by INSTRON. RESULTS: The results of the study are as follows. The initial crack strength was the highest on PFG, and in order of gold bridge, Tescera I, Tescera II, Targis vectris, Tescera IV, Tescera III, and Tescera V. The maximum strength was the highest on gold bridge, and in order of PFG, Tescera I, Tescera IV, Tescera II, Targis vectris, Tescera III, and Tescera V. CONCLUSIONS: The following conclusions were drawn from the results of this study. 1. Flextural strength of implant prosthesis using fiber reinforced composite was higher than average posterior occlusal force. 2. In initial crack strength, Tescera I was stronger than Tescera V, and weaker than PFG. 3. Kinds and number of auxillary components had an effect on maximum strength, and maximum strength was increased as number of auxillary components increased. 4. Maximum strength of Tescera I was higher than Targis vectris, and lower than PFG.

The study of flexural strength of various zirconia ceramics / 대한치과보철학회지

STATEMENT OF PROBLEM: Increasing demand of esthetic restorations made lots of kinds of ceramic materials. Among them, zirconia has been being focused by many dentists. But, mechanical properties of zirconia were still unclear. PURPOSE: The purposes of this study were to analyze the flexural strength of various zirconia ceramics which had been currently used for clinic i.e., In-Ceram Zirconia(Vita Zahnfabrik, Bad Sa ckingen, Germany), Celay Zirconia(Vita Zahnfabrik, Bad Sa ckingen, Germany) and CAD/CAM Zirconia(Adens Zi-Ceram, Seoul, Korea). MATERIAL AND METHODS: The four point bending test(ASTM C1161) was used to measure the flexural strength of a specimen before and after circular heat treatment and fatigue loading. RESULTS: 1. The average value of flexural strengths of CAD/CAM Zirconia, Celay Zirconia, In-Ceram Zirconia in dry condition were 806.5 MPa, 669.9 MPa, 605.6 MPa, respectively. There was a statistically significant difference in strength among the types(P0.05). 3. After fatigue loading in wet condition, the average flexural strengths of CAD/CAM Zirconia, Celay Zirconia, In-Ceram Zirconia were 806.0 MPa, 674.9 MPa, 601.7 MPa, respectively. There was a significant difference in strength among the types(P0.05). CONCLUSION: Besides high esthetic quality, zirconia had sufficiently high mechanical strength.