• 대한치과보철학회지
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• 제28권1호
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• pp.43-61
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• 1990

The laser reflexion method is a new technique which permits precise contactless measurement and observation of tooth mobility as well as tooth movement. The purposes of this study were to clarify the reliability of the laser reflexion method in clinical application and to measure the abutment tooth movement according to clasp design. This study was designed to determine 1) How much a bending movement of the impression plate stand affects the position of the reflexion pattern and how precise the patient bites into plate 2) Which clasp design causes greater movement of the abutment tooth. Under medium and maximum bite forces, tests were performed on central loading position which was 13mm distal to terminal abutment tooth of distal extension removable partial denture. The movement in the mesiodistal and buccolingual directions was measured. The Duncan's New Multiple-Range test was used to compare the means for the four castings under each direction-load combination; and the paired sample t-test was for medium and maximum bite forces. From this experiment, the following results were obtained. 1. The Roach clasp, the combination clasp, the RPI clasp, and the Akers clasp did not significantly differ in their effects on buccolingual movement of the abutment tooth. 2. The direction of abutment tooth movement was not significantly altered by clasp design and all abutment tooth movements were oriented distobuccally. 3. Under medium bite force, the Akers clasp caused greater distal movement of the abutment tooth than did the combination clasp and the RPI clasp. Under maximum bite force, the Akers clasp caused greater distal movement of the abutment tooth than did the RPI clasp. 4. The testing apparatus and procedures used in this study(laser reflexion method) proved to be reliable in clinical application.

• 대한치과보철학회지
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• 제49권4호
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• pp.354-361
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• 2011

구강 스캐너와 CAD/CAM 기술로 인해 컴퓨터로 제작하는 방식이 활발히 보급된 고정식 보철 증례와는 달리, 의치를 디지털 방식으로 제작하는 데에는 아직 한계가 많다. 촉각을 느낄 수 있는 입력 장비와 전자 서베잉의 개념, 그리고 쾌속 조형법의 적용으로 인해 국소의치를 디지털로 제작할 수 있는 솔루션이 최근 소개되고 있다. 본 증례보고에서는 이러한 국소의치의 디지털 솔루션을 이용하여 총 다섯 명의 환자에서 서베이드 금관 및 국소의치를 제작하였다. 인상 과정상의 문제로 모형과 실제 치아 사이의 형태적 차이가 있었던 경우를 제외하고는 국소의치의 적합도는 우수했으며, 장착 후 안정성과 착탈 시의 유지력 또한 임상에서 적용하는 데에 문제가 없었다.

• The Journal of Advanced Prosthodontics
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• 제13권5호
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• pp.304-315
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• 2021

PURPOSE. Esthetic expectations have increased the use of polyetheretherketone (PEEK) clasps as alternatives to Cr-Co in removable partial dentures (RPDs). The objective of this study was to evaluate the retentive force and dimensional change of clasps with different thickness and undercut made from PEEK by the thermo-mechanical fatigue. MATERIALS AND METHODS. PEEK clasps (N = 48) with thicknesses of 1 or 1.50 mm and 48 premolar monolithic zirconia crowns with undercuts of 0.25 mm or 0.50 mm were fabricated. Samples are divided into four groups (C1-C4) and were subjected to 7200 thermal aging cycles (at 5 - 55℃). The changes in the retentive force and dimensions of the clasps were measured by micro-stress testing and micro-CT devices from five measurement points (M1 - M5). One-way ANOVA, paired t-test, two-way repeated ANOVA, and post-hoc tests were used to analyze the data (P < .05). RESULTS. The retentive forces of C1, C2, C3, and C4 groups in initial and final test were found to be 4.389-3.388 N, 4.67 - 3.396 N, 5.161 - 4.096 N, 5.459 - 4.141 N, respectively. The effects of retentive force of all PEEK clasps groups were significant decreased. Thermo-mechanical cycles caused significant dimensional changes at points with M2, M4, and M5, and abraded the clasp corners and increased the distance between the ends of the clasp, resulting in reduced retentive forces (P^* = .016, P^* = .042, P < .001, respectively). CONCLUSION. Thermo-mechanical aging decreases the retentive forces in PEEK clasps. Increasing the thickness and undercut amount of clasps decreases the amount of dimensional change. The values measured after aging are within the clinically acceptable limits.

• 대한치과보철학회지
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• 제49권2호
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• pp.138-144
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• 2011

연구 목적: 본 연구는 최근 개발된 알칼리 이온수 e-WASH의 의치에 부착된 미생물 의치세정 효과에 대해 위상차현미경을 이용한 미생물 관찰법을 통하여 알아보고자 하였다. 연구 재료 및 방법: 실험군 41개, 대조군 26개의 의치를 무작위로 선정하여 실험군에서는 알칼리 이온수e-WASH로, 대조군에서는 수돗물에 5분간 침지 전, 후 의치 내면의 치면세균막을 채취하였다. 위상차현미경으로 구강미생물의 형태적, 종류별 양과 운동성에 대하여 세정 전, 후별 구강미생물의 상태를 관찰하였다. 결과: 1. 알칼리 이온수 e-WASH로 의치를 세정한 실험군에서는 세정 전보다 세정 후 구균의 양, 간균의 양, 간균의 운동성, 실사균의 양, 실사균의 운동성, 콤마/나선균의 양, 콤마/나선균의 운동성 등 모든 조사항목에서 감소하였다 (P<.05). 한편 대조군에서는 구균의 양은 감소하였으나 (P<.05), 다른 조사항목에서는 모두 세정 전, 후 간에 차이가 없었다. 2. 알칼리 이온수e-WASH로 의치를 세정한 실험군에서는 구균의 양, 간균의 양, 간균의 운동성, 실사균의 양, 실사균의 운동성, 콤마/나선균의 양, 콤마/나선균의 운동성 등 모든 조사항목에서 수돗물로 의치를 세정한 대조군보다 각 구강미생물의 양과 운동성이 적게 나타났다 (P<.05). 결론: 위의 결과를 통해 알칼리 이온수 e-WASH가 의치표면의 각종 미생물의 양과 운동성을 효과적으로 감소시키므로 의치세정제로 추천된다.

• 대한치과보철학회지
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• 제25권1호
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• pp.17-40
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• 1987

The purpose of this study was to clarify the effect of clasp design on abutment tooth adjacent to a distal extension base under the influence by the location of functional loading. The RPI clasp, the Akers clasp and the combination clasp were selected for evaluation. Tests were performed at 10Kg, 20Kg, 30Kg loads on the buccal, central, lingual, mesial and distal positions of loading platform of each mandibular distal extension partial denture. The laser reflexion method was used for three dimensional measurement of abutment movement, which is possible to measure precisely without contact. The movement in the mesiodistal(X), buccolingual(Y), and occlusoapical(Z) directions and the rotational movement(R) were measured, and in addition, the total movement (SV) as expressed by the three dimensional summation vector independent of direction was calculated. The data were analyzed using Student t-test, p<.05. The following results were obtained from this study; 1. Clasp design did not generally affect the direction of abutment tooth movement except the movement in an undesirable occlusal direction in case of the Akers clasp and the combination clasp. 2. The greater the load on the prosthesis, the greater was the abutment tooth movement, and the direction of abutment tooth movement was affected by positional loading. 3. Each prosthesis was dislodged from the test base under the small amount of load in the distal load position, and the buccal loading showed the greatest abutment tooth movement under the maximum load. 4. RPI clasp was evaluated as the most favorable design.

• 대한치과보철학회지
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• 제59권4호
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• pp.415-421
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• 2021

소수 잔존치가 남아있거나 치주적으로 불리한 경우 전통적인 가철성 국소의치의 생역학적 예후가 불분명하다. 이러한 경우, 하이브리드 텔레스코픽 이중관 국소의치(hybrid telescopic double crown RPD)는 성공적인 치료의 대안이 될 수 있다. 이 치료방법의 경우 지대치 간의 이차고정 효과가 있으며 응력의 방향이 수직적이고, 지대치 발치 시에 의치의 수리가 용이하다는 점에서 전통적인 가철성 국소의치에 비해 장점을 보인다. 본 증례에서는 전치부의 과개교합을 가진 상하악의 부분 무치악 환자에 있어 상악에는 이중관 의치, 하악에는 임플란트 및 고정성 보철치료가 시행되었다. 장기간 동안 경과관찰 및 유지관리 치료를 시행한 결과, 기능 및 심미적인 면에서 만족할 만한 성과를 얻었기에 이를 보고하고자 한다.

• 한국치위생학회지
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• 제19권6호
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• pp.1067-1075
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• 2019

Objectives: The present study aimed to compare the accuracy of removable partial denture (RPD) frameworks fabricated by selective laser sintering (SLS) before and after electropolishing. Methods: A partially edentulous mandibular model was used as the working model. Scanning of the model was performed using a dental scanner. The framework was designed using CAD software. The metal framework was formed using an SLS 3D printer. 3D scans of the two fabricated prototypes produced before and after electropolishing were overlapped with reference data. The fit was calculated based on Root Mean Square (RMS). Fabrication accuracy was verified using the paired t-test to compare the discrepancy before and after electropolishing. Results: The mean (SD) values of RMS before and after electropolishing were 126.6 (34.19) and 75.86 (21.36), respectively. There was a statistically significant difference before and after electropolishing (p<0.05). Conclusions: Metal frameworks made with SLS 3D printers showed clinically acceptable fit after electropolishing.

• 대한치과기공학회지
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• 제23권2호
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• pp.75-93
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• 2002

This research was preformed for the purpose of preparing the items of standard model of the national dental technician test base on the duty analysis of the dental technician. The results of the duty analysis for the dental technician follows. 1. The dental technician is a profession to make the oral function smooth through the dental supplement and equipment in a scientific method and the skilled technique. 2. The duty of the dental technician are determined as A. preparation for manufacture B. manufacture C. management of the place of the dental technology D. self-development. A. The field of "the preparation for manufacture" are determined as 1. to confirm work authorization 2. To confirm the working model, B. The field of "In manufacture" are determined as 1. to manufacture the temporary crown 2. to manufacture the inlay and crown & bridge prosthesis 3. to manufacture the porcelain fused metal crown prosthesis 4. to manufacture the all ceramic crown prosthesis 5. to manufacture the temporary denture prosthesis 6. to manufacture the partial denture prosthesis 7. to manufacture the complete denture prosthesis 8. to manufacture the attachment prosthesis 9. to manufacture implant prosthesis 10. to manufacture the removable orthodontic device, 11. to manufacture the fixed orthodontic device, 12. to manufacture the orthodontic study cast C. The field of "in management of the dental lab." are determined as 1. management 2. to control the dental lab. D. The field of "In the self-development" are determined as 1. to improve the professionalism 2. self-control. 3. The developing items selected under the duty evaluation of the dental technician are l7s in the manufacture preparation, 1,011s in the manufacture, 7s in the management for the dental technology, 5s in self-development, and in all together 1,040s

• 대한치과기공학회지
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• 제34권4호
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• pp.337-344
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• 2012

Purpose: This study examined the corrosion level by alloy type and pH, and used the corrosion levels as the dental health data. The study utilized one Ni-Cr alloy for the full and removable partial denture metal frameworks and two Ni-Cr alloys for porcelain-fused-to-metal crown, among the non-beryllium dental casting non-precious Ni-Cr alloys. Methods: The alloy specimens were manufactured in $10cm^2$ and stored in the corrosive solution(pH 2.2-4.4) in the electrical water bath($37^{\circ}C$) for seven days. Afterwards, the metal ions were quantitatively analyzed using the ICP. Results: Of the three metal alloys, Bellabond-Plus$^{(R)}$alloy and SOLIBOND N$^{(R)}$alloy, with 22% or higher chrome chemical contents, had higher corrosion resistance than Jdium-100$^{(R)}$alloy with 20% chrome chemical content. In all three alloys, the corrosion of Ni was highest, and metal ion corrosion was higher in the pH 2.2 corrosive solution. Conclusion: Although Ni-Cr alloy was not very corrosive, a Ni-allergic patient should not have Ni-Cr alloy prosthesis. The Ni-Cr alloy for porcelain-fused-to-metal crown should be designed for the dental porcelain to cover the whole crown.

• 구강회복응용과학지
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• 제34권4호
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• pp.317-323
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• 2018

구강암이 상악에 발생하게 되면 원발 부위의 제거를 포함한 외과적 처치 후 비구강 개통(oro-nasal communication)이 발생하게 된다. 비구강 개통으로 인한 음식물의 저류를 막고 및 원할한 발음 및 심미적 회복을 위해서는 구강 폐색장치(Obturator)를 통한 수복이 필요하다.본 증례에서는 구강암으로 인해 우측 상악 편측절제술(hemi-maxillectomy) 시행하고 두경부 방사선 치료의 영향으로 인해 잔존 지대치의 우식과 불량한 치주지지를 보이는 환자에서 구강폐색장치(obturator)를 하이브리드형 이중관의치(hybrid telescopic double crown denture)로 수복하였다. 18개월 간 경과관찰에서 성공적인 예후를 보여 이를 보고하고자 한다.