• 한국세라믹학회지
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• 제40권6호
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• pp.525-529
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• 2003

Biotribological properties, such as wear rate and friction coefficient, of 3Y-TZP and Low Temperature Degradation (LTD) free materials were investigated via a ball(SiC)-on-plate sliding wear test to evaluate the relationship between wear mechanism and phase transformation. Wear test was conducted with a sliding speed of 0.035 m/s at room temperature and at 25$0^{\circ}C$ in air under a normal load of 49 N, respectively. Although friction coefficient of 3Y-TZP was the lowest due to the fine grain size, the highest wear loss and rate were observed due to the debris of monoclinic grains introduced during sliding and their values increased drastically with raising temperature. However, the biotribological properties of LTD-free materials were insensitive to temperature due to the inertness of the phase transformation, suggesting that they may be applicable to the biomechanical parts.

• 대한치과의사협회지
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• 제50권1호
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• pp.6-12
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• 2012

As in all other parts in the body, oral tissue also undergoes dramatic changes with increasing age. Since these changes occasionally go beyond physiological scope, which may result in pathological changes, it is essential for dentist to understand changes caused by normal aging process. With increasing age, tooth morphology and occlusion also varies, especially loss of hard tissue, which is taking place in lifelong time, occurs as a result of tooth wear. When this loss of hard tissue is presented rapidly or excessively, functional and esthetical problems are raised, resulting in lowering quality of life of patient as well as making dental treatment for oral rehabilitation even more complex. Therefore, based on understanding of change in occlusion with increasing age, strategic approaches for maintenance of oral health in both functional and esthetic aspect are required as appropriate restoration and maintenance for progressive tooth wear enables desirable occlusal relationship. Carefully planned-restorative treatment in accordance with changed occlusal relationship is also required in the same context. Instead of taking changes in oral tissue as only a consequence of ageing, it is vital to educate patient and his or her guardian, assuring maintenance of oral hygiene and regular dental check-up are of utmost importance for improved oral health.

• Tribology and Lubricants
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• 제29권4호
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• pp.235-241
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• 2013

The tribological characteristics of dental metal alloys and zirconia were studied by carrying out a friction and wear performance test. In this study, a pin-on-disk-type tester was used and dead weight was employed as the normal load applied to the test specimen. The friction coefficient of dental metal alloys was investigated in terms of their weight and sliding velocity. Microscopic observations were carried out on worn surfaces of specimens. The results indicated that among all metal alloys, Super-A had the highest friction coefficient. Super-A had the lowest amount of wear among all metal alloys, and the amount of wear increased in the following order: Crown & Bridge, Porcelain, and Partial. Crown & Bridge had the best friction coefficient, but the hardness of Crown & Bridge was lower than that of Porcelain and Partial. Experimental measurement results indicated that the disk weight before and after the experiment was the same.

• 구강회복응용과학지
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• 제35권3호
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• pp.113-122
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• 2019

치아마모는 수명증가에 따라 점차 빈도가 증가하는 추세이다. 특히 초기마모 상태에서 치료계획을 잘 수립하여 중등도 마모로 진행하지 않도록 치료계획을 세우는 것이 중요하다. 치아마모의 치료계획을 수립하기 위해서는 치아마모를 정확하게 진단하는 것이 중요하다. 치아마모에 영향을 주는 위험인자는 나이, 식단, 약물 등이 있다. 치아마모를 진단하기 위해 적절한 지표와 평가법을 선택해야 한다. 치아마모 측정지표들은 TWI, Lussi index, BEWE, TWES 등이 존재하며 치아마모 평가방법은 직접관찰법, 치아모형, 임상사진을 이용하는 방법이 있다. 최근 스캐너를 이용한 치아마모 평가법도 소개되고 있다. 치아마모의 위험요소, 측정지표 및 측정방법들과 이와 관련된 문헌들을 고찰하여 각 측정지표와 방법들의 장단점을 비교하여 치아마모를 적절히 진단할 수 있는 방법에 대해 도출해 보았다.

• 대한치과기공학회지
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• 제42권1호
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• pp.55-64
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• 2020

Purpose: The purpose of this study was to investigate the relationship between systemic diseases and denture wear status in elderly. The subjects of this study were 4,340 seniors aged 65 or older who conducted screenings and health surveys using the National Health and Nutrition Survey data during the sixth period (2013, 2014 and 2015). Methods: For the general characteristics and denture wear status according to general systemic diseases, complex sample frequency analysis and cross-analysis were performed. After controlling the general characteristics, complex sample logistic regression analysis was performed to determine the relationship between systemic diseases and denture wear status. Statistical software was used for SPSS (SPSS 23.0 for Windows, SPSS Inc, USA). Significance level was considered as 0.05. Results: A multisample logistic regression analysis was performed to determine the relationship between systemic diseases and denture wear status. The results showed that the dentured state had a significant effect on dyslipidemia and diabetes. Conclusion: Dyslipidemia and diabetes, which are related to denture wearing condition, need to be prevented and treated with regular checkups. In addition, based on the results of the study, it is thought that the elderly need denture prosthetic treatment after tooth extraction. In addition, it can be used as basic data for oral health business plan that can maintain and manage oral health.

• 대한소아치과학회지
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• 제29권2호
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• pp.217-225
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• 2002

시술시간을 줄이는데 유리한 재료인 유동성 복합레진을 유구치부에 사용하려고 고려할 때 중요한 물성 중 하나는 마모저항성이다. 이 연구의 목적은 유동성 복합레진의 마모저항성을 일반복합레진의 마모저항성과 비교하는 것이다. 실험에 사용된 유동성 복합레진으로 1군에서는 Arabesk flow (VOCO, Germany) 2군에서는 Tetric flow (Vivadent, Liechtenstein) 3군에서는 Aeliteflow (Bisco, U.S.A.), 4군에서는 Filtek flow (3M Dental Co, U.S.A)을 사용하였으며 대조군으로 사용한 5군의 복합레진은 Z100 (3M Dental Co, U.S.A)이었다. 시편들(n=10)은 두께 2mm, 지름 5mm의 원통모양으로 제작하여 마모시험 전 $37^{\circ}C$의 증류수에서 7일 동안 담가 놓았다. 제1소구치와 레진시편을 MTS 시스템에서 2Hz로 50,000회 접촉, 마모시켰다. 마모시험시 lateral excursion은 0.4mm, 교합력은 2-100N의 조건이었다. 마모시험후 마모된 부피, 최대마모깊이, 재료자체의 표면경도를 측정하였고 마모 되지 않은 표면과 마모가 일어난 표면을 주사전자현미경으로 관찰하였으며 다음과 같은 결과를 얻었다. 1. 마모된 부피는 3군에서 가장 적었고 4군에서 가장 많았으며 3군<1군<2군<5군<4군의 순서로 증가하였다. 2. 3군, 1군, 2군은 5군이나 4군에 비해 통계적으로 유의하게 마모부피가 적었다(p<0.05). 그러나, 3군, 1군, 2군 사이에서와 5군, 4군 사이에서는 각각 통계적으로 유의한 차이가 없었다. 3. 최대마모깊이는 1군에서 가장 낮았고, 4군에서 가장 깊었으며 1군<3군<5군<2군<4군의 순서로 증가 하였다. 4. 5군의 표면경도는 다른 유동성 복합레진군에 비해 통계적으로 유의하게 높았으나(p<0.05), 마모부피나 최대마모깊이와는 통계적으로 유의한 상관관계를 보이지 않았다. 5. 마모되지 않은 표면과 마모가 일어난 표면을 주사전자현미경으로 관찰한 결과, 유동성 복합레진군과 5군 사이에 마모양상이 다르게 나타나는 것을 볼 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.7-8
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• 2007

• 치위생과학회지
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• 제13권2호
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• pp.151-157
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• 2013

본 연구는 어린이집에서 유아들이 사용하고 있는 칫솔의 칫솔마모 상태를 평가하여, 유아의 칫솔 교체시기에 대한 적절한 기준을 확립하는 데 도움을 주고자 2012년 9월 20일부터 11월 6일까지 1,022개의 칫솔을 수거한 뒤 칫솔마모도 및 마모율을 평가하여 다음과 같은 결과를 얻었다. 1. 칫솔마모도 측정 결과, 조사 대상 칫솔 중 48.5%가 0.400 이상의 마모도를 보였고, 평균 마모도는 $0.421{\pm}0.239$로 조사되어, 전체적으로 높은 칫솔마모도를 보였다. 2. 칫솔마모율 측정 결과, 마모율 2점과 3점이 차지하는 비율이 70.4%였으며, 평균 마모율은 $1.936{\pm}0.848$로 나타나 전체적으로 높은 칫솔마모율을 보였다. 3. 칫솔관리 실태에 대한 조사 결과, 평균 칫솔 교환주기는 5~8주가 63.9%로 가장 많았고, 칫솔 교환방법은 칫솔모의 마모 상태에 따라 교체한다는 응답이 52.7%로 조사되었다. 이상의 결과를 바탕으로, 유아들의 칫솔에 대한 관리가 적절히 이루어질 수 있도록 보육을 담당하는 교사 및 보호자에 대한 지도가 필요할 것이며, 유아의 올바른 칫솔 교체주기에 대한 명확한 기준 확립과 효율적인 구강보건교육 방안도 마련되어야 할 것이다.

• 대한치과기공학회지
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• 제38권3호
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• pp.157-163
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• 2016

Purpose: It is to compare and evaluate the change of the wear rate and phase variation of the Zirconia before and after the sintering after the grinding by a high speed equipment manufactured for the Zirconia. Methods: The specimen of the sintered Zirconia was manufactured as size of $15mm{\times}15mm{\times}2mm$. The grinding has been applied to each of all pieces of each test groups for a minute fit for each condition at same speed of 50,000 rpm by a diamond bur at high speed handpiece with injection of the air and water. For the observation of the surface before and after the sintering of the each test piece, the cross section of it was observed as 100 magnification by a scanning electron microscope after it was coated by PT, and the diffraction analysis was performed by XDR to compare the crystal phase of the Zirconia. The average surface roughness value of all specimens were evaluated. The wear test was performed at room temperature by applying a load of 1kg for 120,000 cycles for the chewing period 6 months. Wear was analyzed for the enamel cusps by measurement of the vertical substance loss with a laser scanner. Conclusion: The phase variation from the tetragonal phase to the monoclinic phase was confirmed in the test group of the pre-sintered Zirconia after the grinding, and the value of the surface roughness and the wear rate was increased in experimental group.

• The Journal of Advanced Prosthodontics
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• 제15권1호
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• pp.33-43
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• 2023

PURPOSE. This study investigated the physical and mechanical changes in the titanium base of three different hybrid abutment materials after cyclic loading by estimating the post-load reverse torque value (RTV), compressive side fulcrum wear pattern of titanium base, and surface roughness. MATERIALS AND METHODS. A total of 24 dental implants were divided into three groups (n = 8 each): Group Z, LD, and P used zirconia, lithium disilicate, and polyetheretherketone, respectively, for hybrid abutment fabrication. RTV was evaluated after cyclic loading with 50 N for 1.2 × 10⁶ chewing cycles. The compressive sides of the titanium bases were analyzed using a scanning electron microscope, and the roughness of the affected areas was measured using an optical profilometer after loading. Datasets were analyzed using Kruskal-Wallis test followed by Mann-Whitney tests with the Bonferroni correction (α = .05). RESULTS. Twenty-three samples passed the test; one LD sample fractured after 770,474 cycles. Post-load RTV varied significantly depending on the hybridabutment material (P = .020). Group P had a significantly higher median of post-load RTVs than group Z (16.5 and 14.3 Ncm, respectively). Groups LD and P showed minor signs of wear, and group Z showed a more pronounced wear pattern. While evaluating compressive side affected area roughness of titanium bases, lower medians were shown in group LD (Ra 0.16 and Rq 0.22 ㎛) and group P (Ra 0.16 and Rq 0.23 ㎛) than in group Z (Ra 0.26 and Rq 0.34 ㎛); significant differences were found only among the unaffected surface and group Z. CONCLUSION. The hybrid abutment material influences the post-load RTV. Group Z had a more pronounced wear pattern on the compressive side of titanium base; however, the surface roughness was not statistically different among the hybridabutment groups.