완전무치악 환자에서 고정성 임플란트 하이브리드 수복물의 임상성적

허윤혁,이양진,권민정,김영균,차민상,Huh, Yoon-Hyuk,Yi, Yang-Jin,Kwon, Min-Jung,Kim, Young-Kyun,Cha, Min-Sang 대한치과보철학회 2013 대한치과보철학회지 Vol.51 No.3

연구 목적: 이 연구의 목적은 완전무치악 환자에서 임플란트 지지 고정성 하이브리드 수복물로 수복한 환자의 임상성적을 알아보는 것이다. 연구 대상 및 방법: 분당서울대병원에서 2003년 10월부터 2009년 11월 사이에 4-6개의 임플란트 지지 고정성 하이브리드 수복물로 수복을 하고 1년 이상 기능한 환자를 대상으로 하였다. 방사선 사진상에서 변연골 흡수량을 측정하고 성별, 해부학적 위치(상악 대 하악), 대합치, 하중시기, 식립 경사도에 따른 차이를 비모수 검정(Mann-Whitney U test) 하고, 외팔보의 길이에 따른 영향을 회귀분석하였으며 합병증을 조사하였다. 유의 수준P<.05로 검정하였다. 결과: 총 16명, 16개 수복물에서 84개의 임플란트의 평균 28개월 후의 골흡수량은 $0.53{\pm}0.39mm$였다. 환자의 성별, 해부학적 위치(상악 대 하악), 대합치, 하중시기에 따른 골흡수량의 유의차는 관찰되지 않았으며(P>.05) 회귀분석 결과 외팔보의 길이와 외팔보 인접 최후방 임플란트의 골흡수량 사이에도 유의성이 없었다(P>.05). 16명중11명의 환자에서 합병증이 발생하였으며 전장재 파절과 인공치 탈락이 가장 많았다. 결론: 짧은 기간의 후향적 연구라는 한계 내에서, 임플란트 지지 고정성 하이브리드 수복물의 평균 골흡수는 매우 적었지만 높은 빈도의 합병증 발생을 보였다. 외팔보 인접 최후방 임플란트의 경사와 관계 없이 외팔보 인접 최후방 임플란트보다 나머지 전방부 임플란트의 변연골 흡수량이 유의하게 컸다. 모든 증례의 외팔보 길이(< 17 mm)는 외팔보 인접 최후방 임플란트 변연골 흡수량에 영향을 주지 않았다. Purpose: The aim of this study was to evaluate clinical outcomes of implant supported fixed-hybrid prostheses (FHP) in the fully edentulous arches. Materials and methods: Patients in this retrospective study were restored with fixed-hybrid prostheses supported by 4 to 6 implants and functioned more than 1 year of loading. Outcome measures were marginal bone change of implant related with sex, anatomical location (maxilla vs. mandible), opposing teeth, loading time of patients, tilting of posterior implant by Mann- Whitney U test and cantilever length of superstructure by regression analysis, and complication rates. Significance level was set P<.05. Results: A total number of 84 implants (16 restorations) placed in 16 patients were observed for 28 months and mean marginal bone loss was $0.53{\pm}0.39mm$. There were no differences of marginal bone loss according to sex, anatomical location (maxilla vs. mandible), opposing teeth, loading time of patients (P>.05), and cantilever length was not significantly related with a marginal bone loss of implant next to cantilever (P>.05). Complication was shown in 11 patients and veneer fracture and dislodging of artificial teeth were most prevalent. Conclusion: Within the limitations of this study, although marginal bone loss of FHP was very little, complication rates were high. Irrespective of tilting of most posterior implants, marginal bone loss of most posterior implants next to cantilever was less than those of the other implants positioned anteriorly. Cantilever length (<17 mm) did not affect a marginal bone loss of most posterior implants.

풀림토크를 이용한 임플란트 토크조절기의 비교

허윤혁(Yoon-Hyuk Huh),조리라(Lee-Ra Cho),김대곤(Dae-Gon Kim),박찬진(Chan-Jin Park) 대한턱관절교합학회 2010 구강회복응용과학지 Vol.26 No.4

상악 완전 무치악 환자의 CAD/CAM 을 이용한 임플란트 식립(NobelGuide™) 및 즉시하중 후 고정성 보철수복 증례

허윤혁(Yoon-Hyuk Huh),이양진(Yang-Jin Yi),김대곤(Dae-Gon Kim),조리라(Lee-Ra Cho),박찬진(Chan-Jin Park) 대한턱관절교합학회 2012 구강회복응용과학지 Vol.28 No.4

Finite Element Analysis of Stress Distribution around Patterned Implants

조리라,허윤혁,김대곤,박찬진 대한치의학회 2012 Journal of korean dental science Vol.5 No.1

Purpose: The purpose of this study was to investigate the effect of patterning on the stress distribution in the bone tissue using the finite element analysis (FEA) model. Materials and Methods: For optimal comparison, it was assumed that the implant was axisymmetric and infinitely long. The implant was assumed to be completely embedded in the infinitely long cortical bone and to have 100% bone apposition. The implant-bone interface had completely fixed boundary conditions and received an infinitely big axial load. von Mises stress and maximal principal stress were analyzed. Conventional thread and 2 or 3 patterns on the upper and lower flank of the thread were compared. Result: The surface areas of patterned implants were increased up to 106~115%. The thread with patterns distributed stress better than conventional thread. Patterning in threads may produce more stress in the implant itself, but reduce stress in the surrounding bone. Stress patterns of von Mises stress were favorable with patterns, while the maximal principal stress was increased with patterns. Patterns in the lower flank showed favorable stress distribution. Conclusion: The patterns in implant thread reduce the stress generated in surrounding bone, but the number and position of patterns were crucial factors in stress distribution.

A two-short-implant-supported molar restoration in atrophic posterior maxilla: A finite element analysis

송호용,허윤혁,박찬진,조리라 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.4

PURPOSE. The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS. Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS. The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION. 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla.

Comparison of the fracture resistances of glass fiber mesh- and metal mesh-reinforced maxillary complete denture under dynamic fatigue loading

임소민,허윤혁,조리라,박찬진 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.1

PURPOSE. The aim of this study was to investigate the effect of reinforcing materials on the fracture resistances of glass fiber mesh- and Cr–Co metal mesh-reinforced maxillary complete dentures under fatigue loading. MATERIALS AND METHODS. Glass fiber mesh- and Cr–Co mesh-reinforced maxillary complete dentures were fabricated using silicone molds and acrylic resin. A control group was prepared with no reinforcement (n = 15 per group). After fatigue loading was applied using a chewing simulator, fracture resistance was measured by a universal testing machine. The fracture patterns were analyzed and the fractured surfaces were observed by scanning electron microscopy. RESULTS. After cyclic loading, none of the dentures showed cracks or fractures. During fracture resistance testing, all unreinforced dentures experienced complete fracture. The mesh-reinforced dentures primarily showed posterior framework fracture. Deformation of the all-metal framework caused the metal mesh-reinforced denture to exhibit the highest fracture resistance, followed by the glass fiber meshreinforced denture (P<.05) and the control group (P<.05). The glass fiber mesh-reinforced denture primarily maintained its original shape with unbroken fibers. River line pattern of the control group, dimples and interdendritic fractures of the metal mesh group, and radial fracture lines of the glass fiber group were observed on the fractured surfaces. CONCLUSION. The glass fiber mesh-reinforced denture exhibits a fracture resistance higher than that of the unreinforced denture, but lower than that of the metal mesh-reinforced denture because of the deformation of the metal mesh. The glass fiber mesh-reinforced denture maintains its shape even after fracture, indicating the possibility of easier repair.

Effect of cyclic loading and retightening on reverse torque value in external and internal implants

조웅래,허윤혁,박찬진,조리라 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.4

PURPOSE. The aim of this study was to evaluate the effect of cyclic loading and screw retightening on reverse torque value (RTV) in external and internal type implants. MATERIALS AND METHODS. Cement-retained abutments were connected with 30 Ncm torque to external and internal type implants. Experimental groups were classified according to implant connection type and retightening/loading protocol. In groups with no retightening, RTV was evaluated after cyclic loading for 100,000 cycles. In groups with retightening, RTV was measured after 3, 10, 100 cycles as well as every 20,000 cycles until 100,000 cycles of loading. RESULTS. Every group showed decreased RTV after cyclic loading. Before and after cyclic loading, external type implants had significantly higher RTVs than internal type implants. In external type implants, retightening did not affect the decrease in RTV. In contrast, retightening 5 times and retightening after 10 cycles of dynamic loading was effective for maintaining RTV in internal type implants. CONCLUSION. Retightening of screws is more effective in internal type implants than external type implants. Retightening of screws is recommended in the early stage of functional loading.

Bone changes around the maxillary posterior teeth opposing the implants in mandible: a clinical study

박찬진,허윤혁,조리라 대한턱관절교합학회 2015 구강회복응용과학지 Vol.31 No.4

Purpose: When the edentulous area is restored by implant prostheses, the opposing hypofunctioned teeth will receive physiologic mechanical stimuli. This study evaluated the bone changes around the maxillary teeth opposing an implant restoration installed in the mandibular posterior area. Materials and Methods: Radiographs of the opposing teeth were taken at prostheses delivery (baseline), 3 and 6 months later. A customized film holding device was fabricated to standardize the projection geometry for the serial radiographs of the opposing teeth. The gray values of the region of interest of each digital image were compared according to time. Repeated measured analysis of variance was performed at the 95% significance level. Results: The gray values of the alveolar bone around the antagonist teeth of implants increased with time. The changes in gray values of the middle area were greater than those of the crestal area. However, the gray values of the mesial and distal areas were not different. The changes in gray values were different according to the unloaded time. Conclusion: A change in bone tissue will occur if a proper physiologic load is again applied to the bone tissues around a hypofunctioned tooth.

Effect of metal primers and tarnish treatment on bonding between dental alloys and veneer resin

추승식,허윤혁,조리라,박찬진 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.5

PURPOSE. The aim of this study was to evaluate the effect of metal primers on the bonding of dental alloys and veneer resin. Polyvinylpyrrolidone solution’ tarnish effect on bonding strength was also investigated. MATERIALS AND METHODS. Disk-shape metal specimens (diameter 8 mm, thickness 1.5 mm) were made from 3 kinds of alloy (Co-Cr, Ti and Au-Ag-Pd alloy) and divided into 4 groups per each alloy. Half specimens (n=12 per group) in tarnished group were immersed into polyvinylpyrrolidone solution for 24 hours. In Co-Cr and Ti-alloy, Alloy Primer (MDP + VBATDT) and MAC-Bond II (MAC-10) were applied, while Alloy Primer and V-Primer (VBATDT) were applied to Au-Ag-Pd alloys. After surface treatment, veneering composite resin were applied and shear bond strength test were conducted. RESULTS. Alloy Primer showed higher shear bond strength than MAC-Bond II in Co-Cr alloys and Au-Ag-Pd alloy (P<.05). However, in Ti alloy, there was no significant difference between Alloy Primer and MAC-Bond II. Tarnished Co-Cr and Au-Ag-Pd alloy surfaces presented significantly decreased shear bond strength. CONCLUSION. Combined use of MDP and VBATDT were effective in bonding of the resin to Co-Cr and Au-Ag-Pd alloy. Tarnish using polyvinylpyrrolidone solution negatively affected on the bonding of veneer resin to Co-Cr and Au-Ag-Pd alloys.

총의치 사용에 대한 환자와 술자간 평가 비교

변진수,허윤혁,조리라,박찬진,Byun, Jin-Soo,Huh, Yoon-Hyuk,Cho, Lee-La,Park, Chan-Jin 대한치과보철학회 2016 대한치과보철학회지 Vol.54 No.4

목적: 총의치를 사용하고 있는 무치악 환자에서 의치 사용에 대한 환자의 평가와 술자간의 평가를 비교하고자 하였다. 대상 및 방법: 의치를 사용한지 최소 1년 이상 경과된 총의치 장착자 중 43명의 환자가 정기검진에 응하였다. 환자에 관한 여러 정보를 얻기 위해 다양한 문헌에서 얻은 자료를 토대로 설문지를 개발하고 술자의 객관적인 평가간 일치도를 분석하였다. 술자의 평가 사항으로는 유지, 안정, 교합과 같은 기능적 항목과 의치의 상태를 포함한다. Friedman test와 Cohen's Kappa값을 이용하여 통계학적인 분석을 시행하였다. 결과: 의치 장착자의 평가와 술자의 평가 간에는 약하거나 약간의 차이가 있다. 상악 의치보다는 하악의치에서 차이가 더 크게 나타났으며 심미와 저작은 중등도의 차이가 있었다. 결론: 의치에 대한 환자의 주관적, 술자의 객관적인 평가는 일치하지 않으나 큰 차이를 보이지 않는다. Purpose: The aim of this study was to compare denture wearer's evaluation and clinician's technical rating for complete denture used on edentulous patients. Materials and methods: Total 43 edentulous patients who had complete denture fabricated more than one year ago were recalled. The questionnaire based on the various literatures was modified and applied to patients for subjective assessments. Functional aspects related to retention, stability, occlusion and denture condition were included in operator's evaluation. In addition, correlations were evaluated between patient's subjective and operator's objective assessments. Friedman test and Cohen's Kappa value were used for statistical analysis. Results: It was found that denture wearers' evaluations were slightly or fairly agree to clinician's rating for complete denture. More differences were found in maxillary denture than mandibular denture and moderate difference was found in esthetic, occlusion aspects. Conclusion: There were slightly or fairly agreement between subjective and objective evaluations.