• 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.

• 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.

• 구강회복응용과학지
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• 제31권3호
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• pp.253-261
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• 2015

만성 치주염 환자 치료시 잔존치 발치 여부를 결정할 때 신중을 기해야 한다. 고정성 또는 가철성 국소의치 치료시 치주조건이 불량한 치아를 지대치로 사용하면 과부하로 조기실패가 우려되어 발치를 고려하지만, 임플란트 고정성 보철물의 경우 잔존치로 전달되는 기능하중을 감소시킬 수 있기 때문에 잔존치를 유지시키는 경우가 많다. 잔존치를 이용한 전악수복시 proprioceptive response를 보존할 수 있어 악간관계와 교합평면 결정시 도움이 될 뿐 아니라 환자의 보철물에 대한 적응이 쉽다. 본 증례의 환자는 치주질환에 의해 다수치 상실 및 대합치의 정출을 보였다. 동요도가 심해 예후가 좋지 않은 치아를 발거하고 소수 잔존치와 임플란트로 전악수복하여 적절한 기능적, 심미적 결과를 얻었다.

• 대한치과보철학회지
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• 제59권2호
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• pp.201-209
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• 2021

가철성 국소의치 치료 시 유지력을 얻는 방법에 따라 많은 연구와 임상적인 적용이 이루어 지고 있다. 그중 한 종류인 이중관 의치는 독일과 스웨덴과 같은 유럽의 나라에서 널리 사용되어지고 있다. 텔레스코픽 이중관 국소의치는 구강 위생관리의 편의성, 지대치로 교합력의 수직적인 전달, 그리고 지대치들 간의 2차적인 고정과 같은 장점들이 있어 클라스프 유지형 가철성 국소의치에 비해 임상적으로 더 나은 결과를 보여줄 수 있다. 본 증례에서 처음에 환자는 자연치를 이용하여 상악에 프릭션핀을 이용한 하이브리드 텔레스코픽 이중관 의치를 제작하였습니다. 7년 뒤 환자의 불량한 구강위생관리 습관과 정기검진의 부재로 지대치들에 치주염이 발생하였고 5개중 4개의 자연치 지대치를 발치하게 되었다. 남은 1개의 자연치 지대치의 내관을 그대로 사용하면서 3개의 추가적인 임플란트를 식립하였다. 대합치인 하악이 고정성 보철임에도 불구하고 전략적인 임플란트 식립으로 인해 환자는 새롭게 제작된 상악 치아-임플란트 연합 이중관 의치에 적응하였고 만족하였다.

• The Journal of Advanced Prosthodontics
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• 제13권6호
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• pp.361-372
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• 2021

PURPOSE. To improve the clinical effects of complete denture use and simplify its clinical application, a digital complete denture restoration workflow (Functional Suitable Digital Complete Denture System, FSD) was proposed and preliminary clinical evaluation was done. MATERIALS AND METHODS. Forty edentulous patients were enrolled, of which half were treated by a prosthodontic chief physician, and the others were treated by a postgraduate student. Based on the primary impression and jaw relation obtained at the first visit, diagnostic denture was designed and printed to create a definitive impression, jaw relation, and esthetic confirmation at the second visit. A redesigned complete denture was printed as a mold to fabricate final denture that was delivered at the third visit. To evaluate accuracy of impression made by diagnostic denture, the final denture was used as a tray to make impression, and 3D comparison was used to analyze their difference. To evaluate the clinical effect of FSD, visual analogue scores (VAS) were determined by both dentists and patients. RESULTS. Two visits were reduced before denture delivery. The RMS values of 3D comparison between the impression made via diagnostic dentures and the final dentures were 0.165 ± 0.033 mm in the upper jaw and 0.139 ± 0.031 mm in the lower jaw. VAS ratings were between 8.5 and 9.6 in the chief physician group, while 7.7 and 9.5 in the student group; there was no statistical difference between the two groups. CONCLUSION. FSD can simplify the complete denture restoration process and reduce the number of visits. The accuracy of impressions made by diagnostic dentures was acceptable in clinic. The VASs of both dentists and patients were satisfied.

• 대한치과보철학회지
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• 제60권3호
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• pp.283-292
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• 2022

임플란트를 이용한 고정성 보철 치료를 위해서는 보철 치료에 적합한 위치에 임플란트가 식립되어야 하며 이를 위해 guided implant surgery와 CAD-CAM을 활용한 보철물 제작이 최근 널리 사용되고 있다. 수술 시에는 surgical guide를 이용해 flapless 방식으로 최소침습 보철수복이 가능 하다. 본 증례의 환자는 86세 남성 환자로 기존 의치 사용 시 불편함으로 치료를 원하였다. 환자는 전신질환으로 인해 가철성 국소의치 사용이 어려워 상악은 총의치, 하악의 경우 임플란트 고정성 보철물 수복하였다. 전신질환으로 인해 높은 출혈 위험성을 가지므로 surgical guide를 사용해 flapless 방식으로 임플란트를 식립하였다. 최종적으로 상악 총의치 및 하악 나사 유지형 지르코니아를 보철물을 제작하였으며, 만족스러운 기능 및 심미 회복을 보였기에 보고하는 바이다.

• 대한치과보철학회지
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• 제57권4호
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• pp.495-505
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• 2019

본 증례는 다수의 치아 상실과 심한 치아 마모로 인해 교합 고경(occlusal vertical dimension)의 감소 및 수복 공간 부족을 보이는 환자에 대한 computer-aided design and computer-aided manufacturing (CAD/CAM) 기술을 활용한 완전 구강 회복 치료이다. 진단 단계에서 교합 고경에 대한 여러 분석을 통해 교합 고경 증가를 통한 완전 구강 회복을 계획하였다. 새롭게 설정된 교합 고경을 반영한 임시 수복물을 환자에게 적용하여 적응시키고, 이중 스캔 방법을 통해 임시 수복물의 정보를 최종 수복물에 옮긴 후, 3D 프린팅을 통해 금속 코핑을 제작하여 최종 고정성 금속 도재 수복물을 완성하였다. 이후 전자 서베잉과 3D 프린팅을 통해 가철성 국소의치 금속 구조물을 제작, 최종 가철성 국소의치로 환자치료를 완료하였다. 이러한 디지털 기술을 활용한 완전 구강 회복 치료로 환자는 기능적, 심미적으로 만족하였고, 술자는 임상적으로 받아들일 만한 치료결과로 판단하였다.

• 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.

• 품질경영학회지
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• 제36권2호
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• pp.59-66
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• 2008

Dental implant has recently become one of the most viable treatment options for regaining the oral function and dental aesthetics compared with conventional fixed or removable dentures. Dental implants vary in material, dimensions, geometries, surface properties, and interface geometries. It has been reported that there has been a proliferation of manufacturers who produce implants using various materials and surface treatments, and the dentist needs to select from over 2,000 different dental implants and abutments in a specific treatment situation. Unfortunately, however, no metrics have been specifically identified for the purpose of quality assessment and selection of an appropriate dental implant. This study aims to provide practical guidelines for quality assessment of dental implant based on clinical data. Like other medical devices and materials, the superiority related to specific characteristics of the dental implant needs to be verified through extensive clinical studies. The procedures of clinical monitoring for dental implants have been proposed along with a case study to exemplify the usefulness of clinical monitoring for the purpose of continuous quality improvement in medical industry.

• 대한치과보철학회지
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• 제44권6호
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• pp.677-682
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• 2006

Statement of problem. Various double crown systems have been used with removable partial dentures in the clinical field. Although retentive force between inner and outer crown are affected by several factors, differences between the retentive forces of different double crown system types are expected. Purpose. The purpose of this study was to evaluate the initial retentive force of outer crowns fabricated by the conventional casting technique in conus and hybrid double crowns. Material and methods. Ten double crowns were fabricated. The groups were as follows. Group 1, double crowns of hybrid inner and outer crowns using the conventional casting method; Group 2, double crowns of conus inner and outer crowns using the conventional casting method. Tensile strengths of double crowns when the inner and outer crowns were separated on a universal testing machine were measured. These values of retentive force were then statistically analyzed using the Kruskal-Wallis test. Results. Retentive force in group 2 was significantly higher than that in group 1(p<.05). Conclusion. The initial retentive forces of double crowns were affected by the types of the double crown system.