The Effect Of Implant Quantity On Stress Distribution Of Single Crown Restoration

Objective: Different implant quantity was applied to restore wide-distanced molar. Three-dimensional finite element models were built up. The aim of this experiment is to study the effects of different implants in single wide-distanced molar implant restoration on the stress distribution of implant-bone interface and to provide theory for clinical application. Method: Three implant designs restored single wide-distanced molar: odel1, ingle small implant (diameter:4.8mm) restoration; model 2, two implants (diameter:3.5mm*2) restoration; model 3, single big implant(diameter:7.0mm).Computed Tomography was used to build up a three-dimensional finite element model. Three-dimensional finite element models were built up on computer with the ALGOR finite-element-analyzing software. After the nodes of the implant-to-bone interface were selected, he stress average values were analyzed.When an axial load of 160N and an oblique load of 100N were applied, the stress distribution of three implant designs was compared. Result: 1.When an axial force was loaded, he maximal stress areas were formed at the neck and root tip region of implants. 2. When an oblique force was loaded, the maximal stress areas were formed at lingual neck region of implants. 3. When an axial force was loaded, the Von Mises stress quantities scope of three model in cortical bone were as follow: single small implant(diameter:4.8mm) restoration:0.3~7.7Mpa; two implants(diameter:3.5mm*2) restoration: 0.2~6.0Mpa; single big implant(diameter:7.0mm) restoration: 0.2~4.7Mpa.4. When an oblique force was loaded, the Von Mises stress quantities scope of three model in cortical bone were as follow: single small implant(diameter:4.8mm) restoration: 0.1~20.5Mpa; two implants(diameter:3.5mm*2) restoration: 0.1~18.2MPa; single big implant(diameter:7.0mm) restoration: 0.1~10.0Mpa. 5. When an axial force was loaded, the Von Mises stress quantities scope of three model in cancellous bone were as follow: single small implant(diameter:4.8mm) restoration: 0.1~0.94MPa; two implants(diameter:3.5mm*2) restoration: 0.08~0.94MPa; single big implant(diameter:7.0mm) restoration: 0.05 ~0.71 MPa. 6. When an oblique force was loaded, the Von Mises stress quantities scope of three model in cancellous bone were as follow: single small implant(diameter:4.8mm) restoration: 0.01~1.41MPa ; two implants(diameter:3.5mm*2) restoration: 0.01~1.22MP; single big implant(diameter:7.0mm) restoration: 0.01~ 0.86MPa. 7. When an axial force was loaded,the maximal stress quantity of single small implant(diameter:4.8mm) restoration was 7.7Mpaï¼›the maximal stress quantity of two implants(diameter:3.5mm*2) restoration was 6.0 Mpa; the maximal stress quantity of single big implant(diameter:7.0mm) restoration was 4.7Mpa. When an oblique force was loaded, the maximal stress quantity of single small implant(diameter:4.8mm) restoration was 20.5Mpa; the maximal stress quantity of two implants(diameter:3.5mm*2) restoration was 18.2Mpa ; the maximal stress quantity of single big implant(diameter:7.0mm) restoration was 10.0Mpa.The stress distribution of single big implant(diameter:7.0mm) restoration was best, The stress distribution of two implants(diameter:3.5mm*2) restoration was better, and the stress distribution of single small implant(diameter:4.8mm) restoration was not good. Conclusion: 1.Implant quantity and diameter had influenced stress distribution between bone and implant.2.When area of two implant was bigger than that of one implant, stress distribution of two implants was better than that of one implant. 3. When area of two implant equaled to that of one implant, stress distribution of one implan was better than that of two implants.4. Implant quantity and diameter hadn't influenced stress distribution place, the maximal stress areas were formed at the neck and root tip region of implants.