Fracture strength and fracture mode of resin root analogs restored with various post and core materials
이병철, 한중석, 이재봉, 양재호, 이선형,
소속 상세정보
이병철 ( Lee Byung-Chul ) - 서울대학교 치과대학 치과보철학교실
한중석 ( Han Jung-Suk ) - 서울대학교 치과대학 치과보철학교실
이재봉 ( Lee Jai-Bong ) - 서울대학교 치과대학 치과보철학교실
양재호 ( Yang Jae-Ho ) - 서울대학교 치과대학 치과보철학교실
이선형 ( Lee Sun-Hyung ) - 서울대학교 치과대학 치과보철학교실
KMID : 0362420020400030287
Abstract
Statement of Problem: Endodontically treated teeth frequently required posts and cores to pro-vide retention and resistance form for crowns. In spite of excellent mechanical properties of met-al post and core, its metallic color can be detected through all ceramic restorations occasionally. To solve esthetic problems of metal post and core zirconia post system has been introduced recently.
Purpose: The purpose of this study was to examine the fracture strength and mode of resin root analogs restored with zirconia, gold and titanium posts with resin, ceramic and metal cores after cementation with metal crowns.
Materials and methods: To avoid the morphological variations of natural teeth, 40 root analogs were fabricated with composite resin. Forty resin root analogs were randomly assigned to four groups according to post and core materials:Group A: cast gold post and core and complete cast crowns, as control.Group B: titanium posts (Parapost, Coltent/Whaledent Inc., NJ, USA) and composite resin cores.Group C: zirconia posts (Cosmopost, Ivoclar AG, Schaan/Liechtenstein) and composite resin coresGroup D: zirconia posts and heat-pressed ceramic cores (IPS Empress Cosmo Ingots, Ivoclar AG)After thermocycling (5 degrees C. 55 degrees C, 30 sec.), cyclic loading was applied at 3mm below the incisal edge on the palatal surfaces at an angle of 135 degree to the long axis (2Hz, 50N, 50000cycles). Fracture strength was measured by universal testing machine (Instron, High Wycombe, UK) and fracture pattern of restored resin root analogs was also evaluated.
Results and Conclusion: Within the limitations of this study following results were drawn.1. Resin root analogs restored with zirconia posts and composite resins demonstrated lowest fracture strength among tested groups.2. There was no significant difference in the fracture strength between zirconia posts and heat pressed glass ceramic cores and cast gold posts and cores3. The fracture strength of resin root analogs restored with titanium posts and composite resin cores was lower than that of gold posts and cores.4. The deep oblique fracture lines were dominantly observed in root analogs restored with cast gold post and core and zirconia post and heat-pressed ceramic core groups.
키워드
Fracture strength; post and core; resin root analog; zirconia; Cyclic loading
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