• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.369-375
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• 2020

PURPOSE. This study evaluated the availability of multi-directionally forged (MDF) titanium (Ti) as a component of removable partial dentures (RPDs). MDF-Ti remarkably improved the mechanical properties of RPDs due to its ultrafine-grained structure. MATERIALS AND METHODS. The wear resistance, plaque adhesion, and machinability of MDF-Ti were tested. As controls, commercially pure (CP) titanium was used for wear, plaque adhesion, and machinability tests. For wear resistance, the volume losses of the titanium teeth before and after wear tests were evaluated. Plaque adhesion was evaluated by the assay of Streptococcus mutans. In the machinability test, samples were cut and ground by a steel fissure bur and carborundum (SiC) point. An unpaired t-test was employed for the analysis of the significant differences between MDF-Ti and the control in the results for each test. RESULTS. Wear resistance and plaque adherence of MDF-Ti similar to those of CP-Ti (P>.05) were indicated. MDF-Ti exhibited significantly larger volume loss than CP-Ti in all conditions except 100/30,000 g/rpm in machinability tests (P<.05). CONCLUSION. Although the wear resistance and plaque adherence of MDF-Ti were comparable to those of controls, MDF-Ti showed better machinability than did CP-Ti. MDF-Ti could be used as a framework material for RPDs.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.635-645
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• 1993

This study was perfomed to investigate the prosthodontic and periodontal status of the abutment teeth in distally extending bridges(DEBs) (78 cases) and removable partial dentures(RPDs) (43 cases) for 122 patients (55 males and 57 females) visiting department of Periodontology, Seoul National University Hospital. The average wearing periods were 67.8 months for DEBs and 66.4 months for RPDs. 38.4% of the patients in DEBs and 35.9% in RPDs complainted of chewing discomfort and 22.6% and 24.4% were not chewing on the prosthodontically - treated sides, respectively. In DEBs, when the restoration for 2nd molar supported by 1st molar & 2nd premolar was grouped to type 1, 1st molar supported by 1st & 2nd premolars was type 2, and 1st & 2nd molars supported by 1st & 2nd premolars was type 3, there was a significant differences only in the tooth mobility score among clinical parameters (type 2>type 1>type 3). In RPDs, when bilateral free-end case was grouped to type 1, and unilateral case was type 2, there was a significant difference in the Gingival index (type 1>type 2). In DEBs, 62.8% of restoration were overcontoured, 72% had interproximal space closures, 30.5% overextended pontics and 86.6% overhanging margins. In RPDs, 24.4% of the restorations were overcontoured, 45.5% had interproxinal space closures and 58.3% overhanging margins. From these results of this study, periodontal problems caused by prosthodontic defects were considered to be contributing factors in chewing discomfort.

• The Journal of Advanced Prosthodontics
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• 제14권2호
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• pp.108-121
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• 2022

PURPOSE. The purpose of this study was to evaluate survival rates and marginal bone loss (MBL) of implants in IC-RPDs. MATERIALS AND METHODS. Seventy implants were placed and used as surveyed crowns in 30 RPDs. The survival rates and MBL around implants based on multiple variables, e.g., position, sex, age, opposing dentitions, splinting, type of used retainer, and first year bone loss, were analyzed. Patient reported outcome measures (PROMs) regarding functional/esthetic improvement after IC-RPD treatment, and complications were also inspected. RESULTS. The 100% implant survival rates were observed, and 60 of those implants showed MBL levels less than 1.5 mm. No significant differences in MBL of implants were observed between implant positions (maxilla vs. mandible; P = .341) and type of used retainers (P = .630). The implant MBL of greater than 0.5 mm at 1 year showed significantly higher MBL after that (P < .001). Splinted implant surveyed crowns showed lower MBL in the maxilla (splinted vs. non-splinted; P = .037). There were significant esthetic/functional improvements observed after treatment, but there were no significant differences in esthetic results based on implant position (maxilla vs. mandible). Implants in mandible showed significantly greater improvement in function than implants in the maxilla (P = .002). Prosthetic complication of IC-RPD was not observed frequently. However, 2 abutment teeth among 60 were failed. The bone loss of abutment teeth was lower than MBL of implants in IC-RPDs (P = .001). CONCLUSION. Class I RPD connected to residual teeth and strategically positioned implants as surveyed crowns can be a viable treatment modality.

• The Journal of Advanced Prosthodontics
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• 제13권5호
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• pp.327-332
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• 2021

PURPOSE. The purpose of this in vitro study was to evaluate the accuracy of digitally designed removable partial denture (RPD) frameworks, constructed by additive and subtractive methods castable resin patterns, using comparative 3D analysis. MATERIALS AND METHODS. A Kennedy class III mod. 1 educational maxillary model was used in this study. The cast was scanned after modification, and a removable partial denture framework was digitally designed. Twelve frameworks were constructed. Two groups were defined: Group A: six frameworks were milled with castable resin, then casted by the lost wax technique into Co-Cr frameworks; Group B: six frameworks were printed with castable resin, then casted by the lost wax technique into Co-Cr frameworks. Comparative 3D analysis was used to measure the accuracy of the fabricated frameworks using Geomagic Control X software. Student's t-test was used for comparing data. P value ≤ .05 was considered statistically significant. RESULTS. Regarding the accuracy of the occlusal rests, group A (milled) (0.1417 ± 0.0224) showed significantly higher accuracy than group B (printed) (0.02347 ± 0.0221). The same results were found regarding the 3D comparison of the overall accuracy, in which group A (0.1501 ± 0.0205) was significantly more accurate than group B (0.179 ± 0.0137). CONCLUSION. In indirect fabrication techniques, subtractive manufacturing yields more accurate RPDs than additive manufacturing.

• 구강회복응용과학지
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• 제32권4호
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• pp.314-321
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• 2016

기존의 후방 연장 국소의치는 재이장을 위한 잦은 내원의 필요성, 클래스프에 의한 지대치로의 과도한 응력, 클래스프의 노출에 의한 비심미성 등의 단점이 있다. 이에 임플란트를 이용하여 부가적인 지지나 유지를 얻는 Implant-assisted RPD(IARPD)는 국소의치의 안정성과 심미성, 그리고 저작 효율 증진에 도움을 줄 수 있다. 또한 의치의 교합면을 지르코니아로 교체한다면 인공치 마모로 인한 대합치의 정출 및 교합평면의 부조화를 예방할 수 있을 것이다. 본 증례는 엇갈린 교합을 가진 상하악 부분 무치악 환자에서 임플란트 고정성 보철물과 임플란트 유지 국소의치를 제작하여 전악 재건 시행한 증례로 주기적인 내원을 통해 기능적, 심미적으로 만족할만한 결과를 얻었기에 보고하고자 한다.

• 구강회복응용과학지
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• 제33권4호
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• pp.284-290
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• 2017

구순구개열 환자에게 가철성 보철치료는 중요한 치료 선택 중 하나이다. 구순구개열 환자에서 만족스러운 기능적 및 심미적 결과를 얻기 위해서는 전통적인 보철 치료법에서 약간의 수정이 필요할 수 있는데, 치주 질환에 이환되어 있으며 소수의 구치만 잔존해 있는 구개열 환자의 경우 이중관에 연결된 가철성 보철이 치료 선택의 대안이 될 수 있다. 이중관이 가철성 국소의치에 연결되면 보철적 안정성과 유지를 증가시키고 치아 장축에 유리한 힘 전달을 최적화하며 심미성도 향상시킨다. 그리고 이중관 의치의 횡단치열궁안정(cross arch stabilization)은 구순구개열 환자의 갈라진 치조제의 안정화에도 도움을 준다. 본 증례는 성인 구순구개열 환자에서 마찰핀(friction pin)을 사용한 혼성 이중관 가철성 국소의치를 제작하여 유지 및 안정성과 함께 심미성도 향상시켜 만족할 만한 결과를 나타낸다.

• 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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• 제54권3호
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• pp.239-245
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• 2016

목적: 임플란트 지지 서베이드 고정성 보철물을 이용한 가철성 국소의치의 합병증을 임상적으로 조사하고, 임플란트 식립위치, 보철물 연결고정여부, 국소의치의 유지장치 종류, 케네디 분류, 대합치에 따른 연관 관계를 조사하고자 하였다. 대상 및 방법: 2000년부터 2016년까지 임플란트 고정성 서베이드 보철물을 이용한 가철성 국소의치로 수복을 받은 환자 11명(남자 7명, 여자 4명)을 대상으로 하였다. 평균 연령은 67.5세였으며, 상악 7개, 하악 4개의 국소의치가 제작되었다. 장착된 국소의치 11개와 이를 지지하는 37개의 임플란트 고정성 보철물의 기계적 합병증, 잔존 자연치아 상태, 주변 연조직 상태 등 모든 합병증과 그와 관련된 요소를 조사하였다. 결과: 장착된 국소의치 11개를 지지하는 총 임플란트는 37개로 국소의치마다 평균 3.4 개의 임플란트 지지 서베이드 고정성 보철물이 이용되었다. 평균 41.5 개월의 추시 기간 동안 발생한 합병증은 임시시멘트 접착 탈락, 대합치 파절/동요, 나사 파절, 나사 풀림, 클래스프 헐거움, 상부 도재파절, 임플란트 주위 골 흡수/동요, 국소의치 인공치아 파절 순으로 발생하였다. 이러한 합병증은 구치부보다 전치부에서, 연결한 보철물 보다 연결하지 않은 보철물에서, 가공선 클래스프를 유지장치로 이용한 보철물에서, 대합치가 의치를 포함하는 보철물보다 자연치열인 경우 합병증 발생이 좀 더 높은 빈도로 나타난 것을 확인 할 수 있었다. 케네디 분류에 따른 합병증 발생 빈도 차이는 유의한 차이를 확인할 수 없었다. 결론: 임플란트 융합 국소의치는 장기간 사용되고 있고 충분히 효과적으로 기능하고 있었다. 하지만 아직까지 이러한 치료의 예후에 대한 축적된 임상 결과는 많이 부족한 실정이므로 좀 더 장기적인 임상 연구가 필요한 상황이다.