• 대한치과보철학회지
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• 제61권2호
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• pp.113-124
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• 2023

목적: 본 연구의 목적은 임플란트 보철물의 종류 및 특성과 생존율 분석을 통해 성공률을 높이는데 도움이 되는 데에 있다. 대상 및 방법: 원광대학교 치과대학 산본치과병원에서 2011~2020년에 식립한 임플란트 중 한 명의 보철전문의에 의해 수복된 사례에 대하여 그 특성과 실패에 대한 상관관계 등을 조사하였다. 실패의 원인은 골유착 실패, 임플란트주위염, 고정체 파절, 지대주 파절, 나사 파절, 나사 풀림, 보철물 파절, 보철물 유지력 상실 등으로 분류했다. 보철방식, 캔틸레버 여부, 식립 위치 등과 임플란트 실패와의 연관성을 분석했다. 결과 분석은 SPSS ver 25.0 (IBM, Chicago, IL, USA)을 이용하여 Chi-square test, Kaplan-Meier 생존분석 등을 통하여 도출했다. 결과: 총 2587개의 임플란트가 식립되었으며, 그 중 1141개의 임플란트가 단일관(Single Crown)으로, 1446개의 임플란트가 고정성 국소의치(Fixed Partial Denture)로 수복되었고 누적생존율은 88.1%이었다. SC의 성공률은 86.2% (984개), FPD의 성공률은 89.6% (1295개)로 통계적으로 유의한 차이를 보였으며 그 중 유의한 차이가 있었던 요인은 지대주 파절, 나사 파절, 나사 풀림 등이었다 (P < .05). 결론: 10년간의 추적조사 결과 생물학적인 요인보다는 생역학적인 요인으로 인한 실패가 더 많이 발생했고 임플란트의 성공률은 보철방식 별로 상이했으며 영향을 미치는 요인도 상이했다. 추후 임플란트의 성공에 관한 추가적인 연구가 더 필요할 것이다.

• 대한골관절종양학회지
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• 제18권2호
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• pp.51-58
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• 2012

목적: 슬관절 주위에 발생한 골종양 환자에서 종양 대치물을 이용한 재건술의 결과와 보행 분석의 유용성을 알아보고자 하였다. 대상 및 방법: 2001년부터 2010년까지 슬관절 주위에 발생한 골종양에 대하여 광범위 절제술 후 종양 대치물을 이용한 재건술을 시행 받은 30명 중 7명을 대상으로 하였으며 기능적 결과 및 보행 분석 검사를 평가하였다. 결과: SF-36 점수는 신체적, 정신적 역할제한 항목에서 각각 100% (100점)으로 높은 점수를 보였으며 일반 건강상태, 신체적 기능 정도, 활력, 사회적 기능에서 낮은 점수를 나타냈다. 또한 MSTS 평가의 종합 평균 점수는 88.1% (23.8점[17-27])였다. 보행 분석 검사상 평균 보행속도 97.2 m/s, 평균 분속수 105.6 step/min, 평균 활보장 111.3 m, 평균 보장 61.5 cm, 유각기 39.8%cycle, 입각기 60.1%cycle, 평균 단하지 지지기 37.1%cycle, 평균 양하지 지지기 13.0%cycle, 평균 발 들림시기 60.7%cycle였다. 결론: 슬관절 주위 종양에 대한 광범위 절제술 후 종양 대치물을 이용한 재건술은 좋은 기능적결과를 기대할 수 있으며, 보행 분석 검사는 술후 환자의 상태를 정량적으로 평가함으로써 보행 모습 및 기능을 객관화 할 수 있는 한 방법으로 사료되며 기능적 평가 방법과 함께 치료 및 술 후 재활 계획을 세우는데 도움이 되리라 생각된다.

• 대한치과기공학회지
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• 제39권1호
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• pp.35-42
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• 2017

Purpose: The purpose of this paper was to evaluate the occurrence of errors regarding adaptation by conducting a three-dimensional assessment comparing the bridge type dental restoration after the cutting process, which has multiple abutments, with a single type dental restoration. Methods: By using ten identical files obtained by scanning the master model, thirty designs were created consisting of ten maxillary right first premolars and ten maxillary right first molars with single crown abutments, along with ten bridge designs with the identical abutment. A 5-axis milling machine was used to produce the design file. The produced denture prostheses were scanned using a silicone replica for a STL file. An evaluation was conducted using 3D analysis software on the master model and each of the thirty data files. Results: The RMS value of the pre-molar (14) was $38.4{\pm}4{\mu}m$ for single and $54.7{\pm}6{\mu}m$ for bridge abutment; therefore, a statistically significant difference was observed for single and bridge designs although both shared the same abutment form (P<.05). Also, the RMS value of the molar (16) was $47.6{\pm}2{\mu}m$ and $56.6{\pm}5{\mu}m$ for the single and bridge designs, respectively, thereby presenting a statistically significant difference (P<.05). Conclusion: As a result, dental prosthesis fabricated using the single method presented better internal adaptation outcomes.

• 대한치과보철학회지
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• 제39권3호
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• pp.306-312
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• 2001

Achieving an aesthetic implant-supported restoration in the single tooth missing case can be challenging when the implant site is in e anterior region. The objective of this report is to focus on presurgical evaluation of implant site and systematic development of related prosthetic modalities. An accurate diagnostic evaluation, a systematically developed pesurgical plan, and knowledge and clinical skill of the various related therapeutic modalities are indispensible. Collection of patient's information, appropriate abutment selection, soft tissue contour, implant axis, and occlusion need to be discussed for aesthetic clinical outcome. For aesthetic restoration, such as surgical guide stent for precise implant positioning customized provisional restoration for development of optimal periimplant soft tissue contours, and fabrication customized abutment (mesiostructure) for veriable emergence profile, are recommended.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.101-112
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• 2004

Osseointegrated implnats have proven to be successful in both full and partial edentulous patients since the 1960s and recently have shown successful results when used to restore single tooth missing. However, in most studies reporting the success of single implants, single implants replacing anterior teeth are more frequently mentioned than posterior single implants. Moreover, in studies regarding posterior single implants, the replaced region seemed to be variable; the maxilla, mandible and areas from the first premolar to the second molar were mentioned. However, considering the difference in bone quality in the mandible and maxilla, and the increased occlusal force in the posterior region, the success rates in each region may be different. In this study, the cumulative success rates and amount of bone loss of single implants replacing the mandibular first and second molar, respectively, were compared and analyzed to come to the following conclusion. 1. The 20 (20 persons) single implants that were placed in the mandibular first molar region were all successful and showed a 100% 5 year cumulative success rate. Among the 27 (24 persons) single implants replacing the mandibular second molar, 8 failed (27.63%) showing a 5 year cumulative success rate of 70.37%. 2. Among the 8 failed implants, one showed symptoms of postoperative infection and one complained of parenthesia. 6 implants failed after functional loading; 5 showed mobility and one resulted in fixture fracture. 3. After the attachment of the prosthesis, there was no significant statistical difference regarding the marginal bone loss in group 1 and group 2 during the checkup period (P>0.05). In conclusion, restoration of the mandibular first molar using single implants was found to be an excellent treatment modality, and when replacing mandibular second molars with single implants, poor bone quality and risk of overloading must be considered.

• 대한치과기공학회지
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• 제41권4호
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• pp.271-278
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• 2019

Purpose: To quantify the effect of the crystallization process on lithium disilicate ceramic crowns that are fabricated using a computer-aided design/computer-aided manufacturing(CAD/CAM) system, and to determine whether they are clinically acceptable by comparing values before and after the crystallization process. Methods: The maxillary first molar was selected as the abutment for the experiments. Ten working models were prepared. Marginal and internal gap of 4 groups of lithium disilicate crowns(n=10) fabricated with conventional method. Comparison was performed using the silicone replica technique and 3D superimposition analysis. The marginal and internal gaps of the restoration were measured before and after the crystallization process of this prosthesis. The average value of each part(the average of values measured before and after the crystallization) was statistically analyzed using paired t-test(α=0.05). Results: The results from the second phase of this research, which compared the average value of the gap between the marginal and internal fits of the lithium disilicate single crown before and after the crystallization process, indicated that the marginal gap was larger and the internal gap was smaller after the crystallization process, and this difference was statistically significant (P<0.05) in all the parts evaluated. Conclusion: While the shrinkage that occurs during crystallization does affect the marginal and internal fit of the prosthesis, it cannot be concluded to be a major effect because the resultant distortion was within the clinically acceptable range.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.71-74
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• 1994

In cementless total hip arthroplasty(THA), an initial stability of the femoral component is mandatory to achieve bony ingrowth and secondary long term fixation. Bone ingrowth depends strongly on relative micromotion and stress distributions at the interface. Primary stability of the femoral component can be obtained by minimizing the magnitude of relative micromotions at bone-prosthesis interface, Hence an accurate evaluation of interface behavior and stress/strain fields in the bone implant system may be relevant for better understanding of clinical situations and improving THA design. However, complete evaluation of load transfer in the bone remains difficult to assess experimentally, Hence, recently finite element method (FEM) was introduced in orthopaedic research field to fill the gap due to its unique capacity to evaluate stress in structure of complex shape, loading and material behavior. The authors developed the 3-dimensional numerical finite element model which is composed of totally 1179 elements off and 8 node blick. We also analyzed the micromotions at the bone-stem interface and mechanical behavior of existing bone prosthesis for a loading condition simulating the single leg stance. The result indicates that the values of relative motion for this well fit Multilock stem were $150{\mu}m$ in maximum, $82{\mu}m$ in minimum, and the largest relative motion developed in medial region of proximal femur with anterior-posterior direction. The proximal region of the bone was much larger in motion than the distal region and the stress pattern shows high stress concentration on the cortex near the tip of the stem. These findings indicates that the loading in the proximal femoral bone in the early postoperative situation can produce micromotions on the interface and clinically cementless TEA patient should not be allowed weight bearing strictly early in the postoperative period.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권2호
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• pp.133-142
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• 2020

Objectives: In this study, we determined the incidence and pattern of screw loosening in patients who received dental implants. Materials and Methods: Patients who received implants between January 2008 and October 2013 and completed their prosthetic rehabilitation were evaluated for the incidence, frequency, and onset of screw loosening using dental charts and radiographs. The association between each factor and screw loosening was analyzed using the chi-square test and a multivariate analysis with binary logistic regression models (P<0.05). Results: Total 1,928 implants were placed in 837 patients (448 males, 389 females), whose follow-up period after loading varied from 0.25 to 70 months (mean period, 31.5 months). Screw loosening occurred in 7.2% of implants. Most cases occurred less than six months after loading. Among those, 22.3% experienced recurrent screw loosening. Screw loosening was most common in the molar region (8.5%) and frequently associated with an implant diameter of ≥5 mm (14.2%). External implant-abutment connections (8.9%) and screw-retained implant prostheses (10.1%) showed higher incidence of problems than internal implant-abutment connections and cement-retained implants, respectively. Screw loosening was most common in implant prostheses with single crowns (14.0%). Conclusion: Within the limits of the current study, we conclude that the incidence of screw loosening differs significantly according to the position of implant placement, the type of implant and manufacturer, implant diameter, the type of implant-abutment connection, the type of retention in the implant prosthesis, and the type of implant prosthesis.

• Journal of Periodontal and Implant Science
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• 제35권1호
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• pp.53-63
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• 2005

Number of fixtures supporting prosthesis for rehabilitation of partial edentulism in distal area is an important factor in distal area to the bone tissue response around dental implant. Optimal number and optimal positioning of dental implant has leaded to the stable condition of bone tissue and successful long-term treatment outcome. This clinical and radiographic study was performed to document and evaluate the short-term result of occlusal rehabilitation by means of implant-supported fixed prostheses (ISPs) especially for partial edentulism in distal area in patients treated for advanced periodontal disease and to verify the number of fixture affecting the bone tissue response. A total of 30 consecutive patients referred because of advanced periodontal disease were included. Before the implant therapy was initiated, periodontal treatment was performed and the outcome evaluated during at least a 6-month period. An individual maintenance care program was designed for each patient. All 75 implants were placed using a 2-stage surgical approach. The patients were divided into 2 groups, in one of which two fixtures were placed and in the other of which three fixtures were placed with tripodal geometry. Following installation of the ISPs, all patients underwent a baseline examination including evaluation of i) oral hygiene, and ii) periodontal/ peri-implant conditions, and iii) radiographs. These examinations were repeated annually during the 1 or 2-year observation period. The results were as follows: 1.No single implant was lost during the observation follow-up period. 1.The percentage of plaque harboring surfaces and bleeding units upon probing were found to be low (<10%), and no soft tissue complications were recorded. 1.Two-fixture group showed bone destruction ranged from 0.0mm to 1.5mm and the mean was 0.31mm. Three-fixture group showed more bone destruction of 0.51mm. There was no statistically difference between two groups. These results suggested that the factor for success is not the number of fixture but the strict maintenance of peri-implant tissue health and initial stability of fixture.

• 대한치과기공학회지
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• 제42권4호
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• pp.348-354
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• 2020

Purpose: Zirconia is differentiated from other ceramics because of its high resistance to corrosion and wear, excellent flexural strength (900~1400 MPa), and high hardness. Dental zirconia with proven mechanical/biological stability is suitable for the manufacture of implants. However, there are limited in vivo studies evaluating stress distribution in zirconia compared with that in titanium implants and studies analyzing finite elements. This study was conducted to evaluate the stress distribution of the supporting bone surrounding zirconia and titanium implants using the finite element analysis method. Methods: For finite element analysis, a single implant-supported restoration was designed. Using a universal analysis program, eight occlusal points were set in the direction of the occlusal long axis. The occlusal load was simulated at 700 N. Results: The zirconia implant (47.7 MPa) von Mises stress decreased by 5.3% in the upper cortical bone compared with the titanium implant (50.2 MPa) von Mises stress. Similarly, the zirconia implant (20.8 MPa) von Mises stress decreased by almost 4% in the cancellous bone compared with the titanium implant (21.7 MPa) von Mises stress. The principal stress in the cortical and cancellous bone exhibited a similar propensity to von Mises stress. Conclusion: In the supporting bone, the zirconia implant is able to reduce bone resorption caused by mechanically transferred stress. It is believed that the zirconia implant can be a potential substitute for the titanium implant by reinforcing aesthetic characteristics and improving stress distribution.