• 대한치과보철학회지
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• 제30권4호
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• pp.582-610
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• 1992

The long-term success of any dental implant is dependent upon the optimization of stresses which occur during oral function and parafunction. Especially, it has been suggested that there is an unique set of problems associated with joining an osseointegrated implant and a natural tooth with a fixed partial denture. For this particular case, although many literatures suggest different ways to avoid high stress concentrations on the bone surrounding the implant under static and dynamic loading conditions, but few studies on the biomechanical efficacy of each assertion have been reported. The purpose of this investigation was to evaluate the efficacies of clinically suggested methods on stress distribution under static load and shock absorption under dynamic load, using two dimensional finite element method. In FEM models of osseointegrated implant-natural tooth supported fixed partial dentures, calculations were made on the stresses in surrounding bone and on the deflections of abutments and superstructure, first, to compare the difference in stress distribution effects under static load by the flexure of fastening screw or prosthesis, or intramobile connector, and second, to compare the difference in the shock absorption effects under dynamic load by intramobile connector or occlusal veneering with composite resin. The results of this analysis suggest that : 1. Under static load condition, using an implant design with fastenign screw connecting implant abutment and prosthesis or increasing the flexibility of fastening screw, or increasing the flexibility of prosthesis led to the .increase in height of peak stresses in cortical bone surrounding the implant, and has little effect on stress change in bone around the natural tooth. 2. Under static load condition, intramobile connector caused the substantial decrease in stress concentration in cortical bone surrounding the implant and the slight increase in stress in bone around the natural tooth. 3. Under dynamic load condition, both intramobile connector and composite resin veneering showed shock absorption effect on bone surrounding the implant and composite resin veneering had a greater shock absorption effect than intramobile connector.

• The Journal of Advanced Prosthodontics
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• 제13권1호
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• pp.12-23
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• 2021

Purpose. The aim of the study was to compare the lingualized implant placement creating a buccal cantilever with prosthetic-driven implant placement exhibiting excessive crown-to-implant ratio. Materials and Methods. Based on patient's CT scan data, two finite element models were created. Both models were composed of the severely resorbed posterior mandible with first premolar and second molar and missing second premolar and first molar, a two-unit prosthesis supported by two implants. The differences were in implants position and crown-to-implant ratio; lingualized implants creating lingually overcontoured prosthesis (Model CP2) and prosthetic-driven implants creating an excessive crown-to-implant ratio (Model PD2). A screw preload of 466.4 N and a buccal occlusal load of 262 N were applied. The contacts between the implant components were set to a frictional contact with a friction coefficient of 0.3. The maximum von Mises stress and strain and maximum equivalent plastic strain were analyzed and compared, as well as volumes of the materials under specified stress and strain ranges. Results. The results revealed that the highest maximum von Mises stress in each model was 1091 MPa for CP2 and 1085 MPa for PD2. In the cortical bone, CP2 showed a lower peak stress and a similar peak strain. Besides, volume calculation confirmed that CP2 presented lower volumes undergoing stress and strain. The stresses in implant components were slightly lower in value in PD2. However, CP2 exhibited a noticeably higher plastic strain. CONCLUSION. Prosthetic-driven implant placement might biomechanically be more advantageous than bone quantity-based implant placement that creates a buccal cantilever.

• 대한치과보철학회지
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• 제62권2호
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• pp.131-139
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• 2024

무치악 환자에서 임플란트를 이용한 보철치료는 임플란트 고정성 보철, 임플란트 융합 국소 의치, 하이브리드 보철물, 임플란트 유지 및 지지 피개의치 등의 다양한 방법이 있다. 본 증례에서는 중등도 이상의 만성 치주염에 이환 되어 전악 발치가 필요한 환자에서 computer guided surgery를 이용하여 계획된 위치에 임플란트를 식립하였다. 상악은 불량한 골질로 초기고정력이 충분하지 않아 지연 부하를 시행하였고 골 유착 기간 동안 임시 의치를 사용하였다. 하악은 안정적인 초기 고정을 얻어 즉시 부하를 이용하여 환자의 불편감을 감소시켰다. 임플란트 일차 안정은 즉시 부하를 얻기 위해 가장 중요한 요소로 여겨지기 때문에 수술 전 반드시 임상적, 방사선학적 평가를 통해 잔존 치조골 양 및 골질을 파악해야 한다.

• 구강회복응용과학지
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• 제36권4호
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• pp.289-295
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• 2020

비심미적인 임플란트유지형 보철물의 심미성 개선은 매우 어려운 문제이며 특히, 상악 전치부 임플란트와 관련되어 있는 경우는 더욱 그러하다. 본 증례는 상악전치부 임플란트의 주기적 배농과 비심미성을 주소로 보철과의사로부터 의뢰된 69세 남자 환자의 심미성 개선에 관한 보고이다. 임플란트는 다소 깊게 식립되어 긴 임상치관길이를 보였으며, 주변 연조직 양도 부족하였다. 임상 검사와 방사선검사 후, 깊게 식립된 임플란트의 제거 대신 예후가 불량한 인접 치아의 발치 후 임플란트를 추가 식립하여 임플란트 유지형 고정성보철물을 제작하고, 깊게 식립된 임플란트는 제거 대신 치조제 증대에 도움을 주기 위해 침수(submergence)시켜 치조제를 증대시키는 방식을 선택하였다. 적절한 진단이 동반된 임플란트 침수가 전치부의 임플란트 비심미성을 개선시킬 수 있는 또다른 대안이 될 수 있을 것이다.

• 대한치과보철학회지
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• 제60권1호
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• pp.127-134
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• 2022

임플란트 실패의 경우에서 과도한 하중 및 염증이 실패율을 높이는 대표적인 원인이 된다. 특히, 임플란트 주변의 불량한 구강위생은 임플란트 실패의 가장 흔한 원인 중 하나이다. 임플란트 상부보철물의 실패가 발생할 경우, 임상의는 남은 고정체를 사용하여 재진단하고 평가하여 치료계획을 수립해야 한다. 임플란트를 추가 식립하여 새로운 보철물을 만들거나 남은 임플란트를 이용하여 임플란트 융합 가철성 의치 및 임플란트 피개의치로 치료를 시행할 수 있다. 본 증례의 환자는 상악 무치악부를 고정성 임플란트 보철물로 수복한 후 구강위생관리가 불가하여 임플란트 보철물 실패한 환자에서 잔존 임플란트의 지대주 및 부가적인 유지 장치를 장착한 milled bar를 이용하여 가철성 임플란트 피개의치로 전환하여 치료하였고 심미성과 저작기능, 지속적인 유지관리 면에서 장기적으로 만족할 만한 결과를 얻었기에 보고하는 바이다.

• 대한치과보철학회지
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• 제33권2호
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• pp.281-299
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• 1995

The purpose of this study was to evaluate the degree of occlusal contact under the fixed implant prosthesis of partially edentulous patients which was hased on occlusal concept of implant prosthesis. From the patients who have free-standing implant supported prosthesis of unilateral partially edentulous area, occlusal and occlusal contact point of th enatural tooth side and implant side of light closure and heavy closure were analyzed by T-scan system throuht pre-and post-adjustment and the degree of occlusal contact was estimated by Shimstock. The following results were obtained : 1. The occlusal force of natural tooth side(NF) from mid-sagittal axis was relatively constant at light and heavy closure through pre-and post-adjustment, but the occlusal force of implant side(IF) was decreased significantly at light closure(P<0.01) and heavy closure(P<0.05) of post-adjustment. 2. Natural tooth side-implant side moment(MIMoment) fo occlusal force from mid-sagittal axis was significant(p<0.05) through pre-and post-adjustment and the deviation from mid-sagittal axis was increased at light closure of post-adjustment, but was decreased at heavy closure of post-adjustment. 3. Comparing the NF and IF, IF was greater at heavy closure of pre-adjustment, and NF was greater at light closure of post-adjustment, and the NF and IF was relatively equally distributed at light closure of pre-adjustment and at heavy closure of post-adjustment. 4. The number of occlusal contact point of natural tooth side(NC) was relatively constant through pre-and post-adjustment, but the number of occlusal contact point of implant side(IC) was significantly decreased(P<0.05) at light closure of post-adjustment, and was not significant but was lesser at heavy closure of post-adjustment. 5. Difference of the NC and IC was greater at light closure of post-adjustment, but it was less at heavy closure of post-adjustment, and therefore occlusal contact point of natural tooth side and implant side was relatively equally distributed at heavy closure of postadjustment. 6. When bilaterally distribution of occlusal force and occlusal contact point was established, degree of occlusal contact of implant suporoted prosthesis with opoosing teeth at light clousre was $34.13{\pm}21.69{\mu}m$.

• 대한치과의사협회지
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• 제31권6호통권289호
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• pp.438-443
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• 1993

• 대한심미치과학회지
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• 제10권2호
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• pp.51-62
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• 2001

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.167-172
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• 2020

PURPOSE. The aim of the present study was to investigate the passive fit of metal substructure after repetitive firing processes in implant-supposed prosthesis. MATERIALS AND METHODS. Five implants (4 mm diameter and 10 mm length) were placed into the resin-based mandibular model and 1-piece of screw-retained metal substructure was produced with the direct metal laser sintering (DMSL) method using Co-Cr compound (n = 10). The distance between the marked points on the multiunit supports and the marginal end of the substructure was measured using a scanning electron microscope (SEM) at each stage (metal, opaque, dentin, and glaze). 15 measurements were taken from each prosthesis, and 150 measurements from 10 samples were obtained. In total, 600 measurements were carried out at 4 stages. One-way ANOVA test was used for statistical evaluation of the data. RESULTS. When the obtained marginal range values were examined, differences between groups were found to be statistically significant (P<.001). The lowest values were found in the metal stage (172.4 ± 76.5 ㎛) and the highest values (238.03 ± 118.92 ㎛) were determined after glaze application. When the interval values for groups are compared with pairs, the differences between metal with dentin, metal with glaze, opaque with dentin, opaque with glaze, and dentin with glaze were found to be significant (P<.05), whereas the difference between opaque with metal was found to be insignificant (P=.992). CONCLUSION. Passive fit of 1-piece designed implant-retained fixed prosthesis that is supported by multiple implants is negatively affected by repetitive firing processes.

• 대한치과보철학회지
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• 제60권4호
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• pp.382-394
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• 2022

심한 치주염을 가진 환자의 치료는 환자의 개개 치아의 정확한 진단과 전략적인 치료 계획을 통해 단계적으로 진행되어야 한다. 임플란트 지지 고정성 보철 수복은 국소의치에 비해 환자의 만족도가 높고, 안정적인 수직 고경을 유지할 수 있는 장점이 있지만, 경조직이 부족한 다수 치아 결손 부위에서는 심미적인 측면의 실패와 치료 기간이 길어진다는 점의 단점이 있을 수 있다. 또한 통상의 고정성 보철물을 제작하고 장착하는 데에는 일정 기간이 소요되는데, 이 기간 동안 임시 보철물은 치아의 기계적, 생물학적, 심미적 요구 조건을 만족시켜야 한다. 이번 증례 보고에서는 상악과 하악의 부분 무치악 환자에서 단계적인 접근을 통한 임플란트 고정성 보철물을 수복한 증례를 보고하고자 한다.