두 개의 임플란트를 이용한 3본 고정성 국소의치에서 가공치 위치에 따른 하악골에서의 응력 분포 및 변형에 관한 삼차원 유한요소법적 연구 (The three dimensional finite element analysis of stress distribution and deformation in mandible according to the position of pontic in two implants supported three-unit fixed partial denture)

서지정보

· 발행기관 : 대한구강악안면외과학회
· 수록지 정보 : 대한구강악안면외과학회지 / 34권 / 2호 / 166 ~ 179페이지
· 저자명 : 김동수, 김일규, 장금수, 박태환, 김규남, 손충렬

초록

Excessive concentration of stress which is occurred in occlusion around the implant in case of the implant supported fixed partial denture has been
known to be the main cause of the crestal bone destruction. Therefore, it is essential to evaluate the stress analysis on supporting tissue to get higher
success rates of implant.
The purpose of this study was to evaluate the effects of stress distribution and deformation in 3 different types of three-unit fixed partial denture supported
by two implants, using a three dimensional finite element analysis in a three dimensional model of a whole mandible. A mechanical model of
an edentulous mandible was generated from 3D scan, assuming two implants were placed in the left premolars area. According to the position of pontic,
the experiments groups were divided into three types. Type I had a pontic in the middle position between two implants, type II in the anterior position,
and type III in the posterior position. A 100-N axial load was applied to sites such as the central fossa of anterior and posterior implant abutment,
central fossa of pontic, the connector of pontic or the connector between two implants, the mandibular boundary conditions were modeled considering
the real geometry of its four-masticatory muscular supporting system.
The results obtained from this study were as follows;
1. The mandible deformed in a way that the condyles converged medially in all types under muscular actions. In comparison with types, the deformations
in the type II and type III were greater by 2-2.5 times than in the type I regardless of the loading location.
2. The values of von Mises stresses in cortical and cancellous bone were relatively stable in all types, but slightly increased as the loading position
was changed more posteriorly.
3. In comparison with type I, the values of von Mises stress in the implant increased by 73% in Type II and by 77% in Type III when the load was
applied anterior and posterior respectively, but when the load was applied to the middle, the values were similar in all types.
4. When the load was applied to the centric fossa of pontic, the values of von Mises stress were nearly 30 35% higher in the type III than type I or
II in the cortical and cancellous bone. Also, in the implant, the values of von Mises stress of the type II or III were 160 170% higher than in the
type I.
5. When the load was applied to the centric fossa of implant abutment, the values of von Mises stress in the cortical and cancellous bone were relatively
20 25% higher in the type III than in the other types, but in the implant they were 40-45% higher in the type I or II than in the type III.
According to the results of this study, musculature modeling is important to the finite element analysis for stress distribution and deformation as the
muscular action causes stress concentration. And the type I model is the most stable from a view of biomechanics. Type II is also a clinically acceptable
design when the implant is stiff sufficiently and mandibular deformation is considered. Considering the high values of von Mises stress in the cortical
bone, type III is not thought as an useful design.

영어초록

Excessive concentration of stress which is occurred in occlusion around the implant in case of the implant supported fixed partial denture has been
known to be the main cause of the crestal bone destruction. Therefore, it is essential to evaluate the stress analysis on supporting tissue to get higher
success rates of implant.
The purpose of this study was to evaluate the effects of stress distribution and deformation in 3 different types of three-unit fixed partial denture supported
by two implants, using a three dimensional finite element analysis in a three dimensional model of a whole mandible. A mechanical model of
an edentulous mandible was generated from 3D scan, assuming two implants were placed in the left premolars area. According to the position of pontic,
the experiments groups were divided into three types. Type I had a pontic in the middle position between two implants, type II in the anterior position,
and type III in the posterior position. A 100-N axial load was applied to sites such as the central fossa of anterior and posterior implant abutment,
central fossa of pontic, the connector of pontic or the connector between two implants, the mandibular boundary conditions were modeled considering
the real geometry of its four-masticatory muscular supporting system.
The results obtained from this study were as follows;
1. The mandible deformed in a way that the condyles converged medially in all types under muscular actions. In comparison with types, the deformations
in the type II and type III were greater by 2-2.5 times than in the type I regardless of the loading location.
2. The values of von Mises stresses in cortical and cancellous bone were relatively stable in all types, but slightly increased as the loading position
was changed more posteriorly.
3. In comparison with type I, the values of von Mises stress in the implant increased by 73% in Type II and by 77% in Type III when the load was
applied anterior and posterior respectively, but when the load was applied to the middle, the values were similar in all types.
4. When the load was applied to the centric fossa of pontic, the values of von Mises stress were nearly 30 35% higher in the type III than type I or
II in the cortical and cancellous bone. Also, in the implant, the values of von Mises stress of the type II or III were 160 170% higher than in the
type I.
5. When the load was applied to the centric fossa of implant abutment, the values of von Mises stress in the cortical and cancellous bone were relatively
20 25% higher in the type III than in the other types, but in the implant they were 40-45% higher in the type I or II than in the type III.
According to the results of this study, musculature modeling is important to the finite element analysis for stress distribution and deformation as the
muscular action causes stress concentration. And the type I model is the most stable from a view of biomechanics. Type II is also a clinically acceptable
design when the implant is stiff sufficiently and mandibular deformation is considered. Considering the high values of von Mises stress in the cortical
bone, type III is not thought as an useful design.

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