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Objective:To observe the effect of orbital implant load angle on the stress distribution of peri-implant surface.Methods:The 3D finite element analysis model of orbital implant with diameter of 3.75 mm and length of 6 mm was established.A force of 20 N was applied on the model at various angles.The stress distribution and displacement of the implant were recorded and analyzed.Results:Under 0°,1 0°,20°,30°,45°and 90°the maximum stress(MPa)on the peri-implant surface was 3.1 73,6.535,1 0.506,1 4.1 68, 1 8.949 and 24.755,the maximum displacement(μm)of the implant was 1 .761 ,3.654,7.665,1 1 .567,1 6.774 and 25.072,respec-tively.Conclusion:The loading angle is an important factor influencing stress and displacement of peri-implant bone.
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<p><b>OBJECTIVE</b>This study aims to observe the effect of orbital implant lengths on stress distribution in peri-implant surfaces.</p><p><b>METHODS</b>The three-dimensional finite element analysis models of craniofacial and orbital implants with a diameter of 3.75 mm and lengths of 3, 4, 6, and 10 mm were established. A force of 20 N was applied to the models. The stress and displacement distribution under every condition were recorded and analyzed.</p><p><b>RESULTS</b>The loading direction along the implant axis and the stress concentration on the implant root were observed. The loading direction was at a 45 degree angle relative to the implant axis, and the stress concentration was located at the implant neck and the first screw thread. The maximum stress of the 3 mm implant was significantly higher than that under the other two loading directions. The maximum displacement of the four lengths exhibited no significant change. Given the same implant length, stress, and displacement, the peak of the implant axial direction was lower than that of the 45 degree direction. The loading type was an important factor influencing the stress and displacement of peri-implant bones.</p><p><b>CONCLUSION</b>The implants of more than 4 mm length can be considered for clinical use. The implant of 3 mm length should be implanted in a region with thicker cortical bone.</p>
Subject(s)
Biomechanical Phenomena , Dental Implants , Dental Prosthesis Design , Dental Stress Analysis , Finite Element Analysis , Orbital Implants , Stress, MechanicalABSTRACT
Objective To investigate the influence of Herba Epimedium, a kidney-strengthening Chinese herb, on the regenerate ossification of nano-hydroxyapatite/collagen/ polylactic acid (nHAC/PLA) in the repair of rabbit mandibular defect. Methods Sixteen rabbit models with 10 mm × 8 mm subperiosteal mandibular defect were established. The rabbits were randomly divided into 2 groups, namely Herba Epimedium group and control group. In both groups, the left mandibular defect region (short for left side) was not filled with any material, while the right mandibular defect region ( short for right side) was filled with nHAC/PLA. On week 2, 4, 8, 12 after modeling, rabbits in each group were killed, and then the macro-view, imageology and histology of the bilateral mandibles were observed. The data of the regenerate bone areas were calculated and analyzed with analysis of variance (ANOVA) . Results The imageological results showed bone mineral density in the right side of Herba Epimedium group and the control group, and in the left side of Herba Epimedium group were higher than those in the left side of the control group on week 2, 4, 8, 12 after modeling. The histological results showed that the regenerate ossification in the right side of Herba Epimedium group and the control group was superior to that in the left side of the corresponding groups, with more regenerative bone and vessels. In the right side of Herba Epimedium group and the control group, amount of bone-like tissues were grown into nHAC/PLA, and the maturity degree of bone tissue was increased with the prolongation of time. And the changes were more obvious in the right side of Herba Epimedium group, showing as the remaining of nHAC/PLA having been surrounded and replaced by regenerative bone tissue. Regenerative bone area was increased in both sides of Herba Epimedium group, which differed from the same side of the control group (P<0.05) . The differences of the regenerative bone area were also significant between the left side and right side of the same group (P<0.05) . Conclusion Herba Epimedium can effectively accelerate the repair of mandibular defect, and nHAC/PLA is of good biocompatibility, osteoinduction and bone conduction, and can be expected for bone defect repairing in clinic.
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Objective To evaluate the clinical efficacy of Yinhe gargle on infected root canals. Methods Forty-seven cases of root canal infection ( involving 48 affected teeth) were randomly divided into two groups. The experimental group (22 cases involving 22 affected teeth) was given intracanal medicament with Yinhe gargle, and the control group ( 25 cases involving 26 affected teeth) was given root canal disinfection with camphor phenol. After intracanal medicament for one week, therapeutic effect and safety were evaluated in the two groups. Results ( 1) During root canal disinfection, none of the subjects had adverse reaction such as hypersensitiveness or cauterization of soft tissue. Canal obturation was available after the first intracanal medicament for the infected root canals. (2) After intracanal medicament for one week, the effective rate in the experimental group was 95.45%, and was 100.00%in the control group, the difference being in significant (P>0.05). Conclusion Yinhe gargle has similar disinfection effect to camphor phenol on infected root canals, and it can be used as disinfection medicament for root canals.