An Investigation Of Retention Of Overdenturewith Magnetic Attachment After Partly Buffering

ObjectiveAccording simulation the absorption of alveolar ridges to contrast the retention ofoverdenture with magnetic attachment after partly absorption with before to analyzingthe relation between the force of dislocation and the the time of treatment. ToInvestigate the effect of the change of retention of overdenture with magneticattachment and the path of movement, to study the effect of partly absorption on theretention of magnetic attachment after the absorption of distal alveolar ridges.MethodOne healthy cross-breed maleness majority dog was used in the study. Extractedall of mandibular teeth except the canine teeth of anterior teeth to establish the modelof overdenture with magnetic attachment needed in the study. They wereexecuted6weeks later. And then donduct teeth preparation, prepare the canine teeth andmade the magnetic attachment. Depart the abutment part of mandibular model,elevatethe model containing armature, establish the model of distal alveolar bridge absorption(MAGFIT EX 600W magnetic attachment), mesure the change of retention force ofoverdenture with magnetic attachment in different absorption conditions(the amount ofabsorption respective are 0mm,0.4mm,0.8mm, 1.2mm,1.6mm,2.0mm, dividing 1-6groupaccording to this),record the data. The data were analyzed by SAS 8.12 statisticssoftware and the analysis of variance (ANOVA) was performed to compare the retentionforce prependicular direction and 60°bolique to the anodic of the same exerting pointbefore and after the buffering of the denture, p＜0.01. Draw the curve of tensile force-time, conduct contrast analysis.ResultThere were no obvious difference in the retention of prependicular direction ofanterior teeth area and the posterior teeth area and 60°bolique to the anodic ofposterior teeth area. The retention force the elevation of 60°bolique to the anodic ofanterior teeth area was obvious difference in the course of absorption. by ANOVA.There was no obvious difference between group 1 and group 2, and in the 3-6 group, butobvious degrade retention force was detected in group 2-3.In the unbuffering,the retention force of prependicular direction of anterior teetharea was decreased followed the absorption of alveolar, there was no obviousdifference between group 1 and group 2, and between group 4 and group 5,but obviousdegrade retention force was detected in group 2-3, group 3-4 and group 5-6 (p＜0.01).the retention force of 60°bolique to the anodic of anterior teeth area increased in group1-2.and then the retention force all decreased in each group.There was significantdifference in the change of each group(p＜0.01). There were no significant difference inthe retention of prependicular direction and 60°bolique to the anodic of posteriorteeth area in unbuffering.The tensile force increased with time in the dislocation curve of anterior teeth areain buffering, attain the peak value at 10-20s,then decreased dramatically, the decreasedcurve was a vertical straight line. In the initial stage,the tensile force increased withtime in the dislocation curve of anterior teeth area in unbuffering, attain the peak valueat 10s, then decreased dramatically, but the last part of the curve was gently and becametardy. The tensile force increased with time in the dislocation curve of posterior teetharea in buffering, attain the peak value at 50-60s,retain the fluctuation at the peak,anda platform presented in the top of the curve,then became decrease. The tensile forceincreased rapidly with time in the dislocation curve of posterior teeth area inunbuffering, attain the peak value in 10s,then decreased slowly, and this was obvious inthe dislocation curve of 60°bolique to the anodic.Conclusion The retention force of overdenture with magnetic attachment in the anterior teetharea was obviously degraded. While the partly buffering of the magnetic attachment canelevate the retention of anterior teeth area after the absorption of alveolar ridge.