구치용 도재소부금관과 전부도재관에 파절을 일으키는 한국음식에 관한 연구
A comparative study on the correlation between Korean foods and the fractures of PFG and all ceramic crowns for posterior applications
김정호, 이재봉,
소속 상세정보
김정호 ( Kim Jeong-Ho ) - 서울대학교 치과대학 치과보철학교실
이재봉 ( Lee Jai-Bong ) - 서울대학교 치과대학 치과보철학교실
KMID : 0362420090470020156
Abstract
연구목적: 4종 구치용도재관 (Full-porcelain-occlusal-surfaced PFG, Half-porcelain-occlusal-surfaced PFG, Empress 2, Ice Zirkon)과 선별된 한국음식의 fracture load와 dynamic cyclic load를 측정하여 구치용 도재관에 파절을 일으킬 가능성이 있는 한국음식을 선별하는데 있다.
연구재료 및 방법: 4종의 각 porcelain 보철물 system 당 15개의 축대칭을 이루는 crown을 제작했다. 이때 occlusal reduction은 1.5 - 2.0 mm로 했다 (중심부 1.5mm, 교두부 2.0 mm). 각 15개의 시편의 교합면 중앙부에 직경 5 mm의 stainless steel ball을 위치시킨 후 Instron 4465 universal testing machine (Instron, Norwood, MA USA)을 이용하여 5mm/min의 crosshead speed로 수직 부하를 주어 파절을 일으키는 최대 부하 (N)를 기록했다. 이후, 한국음식 중 삶은 게, 닭 (뼈포함), 소갈비(뼈포함), 마른 오징어, 건멸치, 사탕, 호두껍질을 표본으로 설정하고 이들을 파절시키는 최대 부하 (N)를 universal testing machine (Instron 4465) 에서 측정하여 기록했다. 각 항목당 15번을 측정했다. 음식물을 파절시킬 때 필요한 최대부하와 각 보철물의 파절저항을 비교하여 한국의 식습관과 도재를 이용한 보철물 파절의 상관관계를 조사하였다. fracture loads는 analysis of variance 와 Post Hoc tests를 이용해서 분석하였다 (α= 0.05). 차후에 위에서 얻은 결과를 바탕으로 Hydraulic Dynamic Fatigue Testing Machine (858 Bionix II, MTS systems, Eden Prairie, MN USA)를 이용하여 4종의 각 porcelain 보철물 system당 5개의 crown에 14Hz Cyclic Load를 가하여 crown에 파절을 일으키는 masticatory cycle수를 알아 보았다. Load 수치는 41.0 N (건멸치 파절강도), 169.0 N (마른오징어 파절강도), 382.9N (닭뼈 파절강도), 2224.8 N (사탕 파절강도)로 설정하였다.
결 과: 95% confidence intervals for mean fracture load는 2599.3 - 2809.1 N (완전도재교합면 PFG), 3689.4 - 3819.9 N (반도재교합면 PFG), 1501.2 - 1867.9 N (Ice Zirkon), 803.2 - 1188.5 N (Empress 2)로 나왔고 95% confidence intervals for dynamic cyclic load on fracture는 instron 상에서 도재보철물에 파절을 일으키지 않은 load인 2224.8 N (사탕 파절강도)와 382.9 N (닭뼈 파절강도)로 실험했을 때, 2224.8 N에서 4796.8 - 9321.2 cycles (완전도재교합면 PFG), 2224.8 N에서 881705.1 -1143565.7 cycles (반도재교합면 PFG), 382.9 N에서 979993.0 - 1145773.4 cycles (Ice Zirkon), 382.9 N에서 564.1 - 954.7 cycles (Empress 2)로 나왔다.
결 론: 통계학적으로 유의할 만한 차이가 그룹들 간 fracture load에서 나타났다. 한국음식물 중 소갈비 (뼈포함)와 사탕 (자두맛캔디)은 구치용 도재보철물을 파절시킬 가능성이 있는 음식물로 밝혀졌다. 단일수직부하에서는 파절이 생기지 않는 경우라 할지라도 dynamic cyclic load를 줄 경우 일정 주기 후에 파절이 생기는 결과를 얻을 수 있었다.
Statement of Problem: Recently, there have been increased esthetic needs for posterior dental restorations. The failure of posterior dental ceramic restoration are possible not only by the characters of the component materials but also by the type of food.
Purpose: The research aim was to compare the in vitro fracture resistance of simulated first molar crowns fabricated using 4 dental ceramic systems, full-porcelain-occlusal-surfaced PFG, half-porcelain-occlusal-surfaced PFG, Empress 2, Ice Zirkon and selected Korean foods.
Material and Methods: Eighty axisymmetric crowns of each system were fabricated to fit a preparation with 1.5- to 2.0-mm occlusal reduction. The center of the occlusal surface on each of 15 specimens per ceramic system was axially loaded to fracture in a Instron 4465, and the maximum load (N) was recorded. Afterwards, selected Korean foods
specimens (boiled crab, boiled chicken with bone, boiled beef rib, dried squid, dried anchovy, round candy, walnut shell) were prepared. 15 specimens per each food were placed under the Instron and the maximum fracture loads for them were recorded. The 95% confidence intervals of the characteristic failure load were compared between dental ceramic systems and Korean foods. Afterwards, on the basis of previous results, 14Hz cyclic load was applied on the 4 systems of dental ceramic restorations in MTS. The reults were analyzed by analysis of variance and Post Hoc tests.
Results: 95% confidence intervals for mean of fracture load 1. full porcelain occlusal surfaced PFG Crown: 2599.3 to 2809.1 N 2. half porcelain occlusal surfaced PFG Crown: 3689.4 to 3819.8 N 3. Ice Zirkon Crown: 1501.2 to 1867.9 N 4. Empress 2 Crown: 803.2 to 1188.5 N 5. boiled crab: 294.1 to 367.9 N 6. boiled chicken with bone: 357.1 to 408.6 N 7. boiled beef rib: 4077.7 to 4356.0 N 8. dried squid: 147.5 to 190.5 N 9. dried anchovy: 35.6 to 46.5 N 10. round candy: 1900.5 to 2615.8 N 11. walnut shell: 85.7 to 373.1 N under cyclic load (14Hz) in MTS, fracture load and masticatory cycles are: 1. full porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 4796.8 - 9321.2 cycles under 2224.8 N (round candy)load, no fracture under smaller loads. 2. half porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 881705.1 - 1143565.7 cycles under 2224.8 N (round candy). no fracture under smaller loads. 3. Ice Zirkon Crown fractured at 95% confidence intervlas of 979993.0 - 1145773.4 cycles under 382.9 N (boiled chicken with bone). no fracture under smaller loads. 4. Empress 2 Crown fractured at 95% confidence intervals of 564.1 - 954.7 cycles under 382.9 N (boiled chicken with bone). no fracture under smaller loads.
Conclusion: There was a significant difference in fracture resistance between experimental groups. Under single load, Korean foods than can cause fracture to the dental ceramic restorations are boiled beef rib and round candy. Even if there is no fracture under single load, cyclic dynamic load can fracture dental posterior ceramic crowns. Experimental data with 14 Hz dynamic cyclic load are obtained as follows. 1. PFG crown (full porcelain occlusion) was failed after mean 0.03 years under fracture load for round candy (2224.8 N). 2. PFG crown(half porcelain occlusion) was failed after mean 4.1 years under fracture load for round candy (2224.8 N). 3. Ice Zirkon crown was failed after mean 4.3 years under fracture load for boiled chicken with bone (382.9 N). 4. Empress 2 crown was failed after mean 0.003 years under fracture load for boiled chicken with bone (382.9 N).
키워드
파절저항;도재소부금관;전부도재관;주기적 교합압
fracture resistance;PFG;all ceramic crown;cyclic load;masticatory load
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