Effects Of Dynamic And Static Loading Of Three Abutment Materials On Bone Stress Under Different Implantation Conditions

Objective:Based on the three-dimensional finte element method,the influence of three fixed implant design schemes on the biomechanics of implant fixation repair of edentous maxilla under different upper support materials was compared and analyzed,so as to explore a more optimal fixed implant repair design scheme.Methods: The conical beam CT data of an adult normal jaw was selected,and the edentulous maxillary model was obtained by using the Mimics software through Boolean manipulation according to the threshold command segmentation.The Geomagic Studio software was used to construct the 3D finite element model of the edentulous maxillary complete dental arch implant fixed denture combined with the specific model parameters.According to the different upper stent materials and distal implant implantation methods in the maxillary posterior region,assembly of different schemes was carried out to establish six different fixed implant repair models of maxillary edentors,including three scheme design models of the whole dental arch titanium stent group and the polyether ether ketone stent group(Scheme 1: All-on-4 design in accordance with the routine clinical application).Two implants were implanted vertically into the bilateral incisor region of the maxilla,and the other two implants were implanted into the bilateral second premolar region at an Angle of30°.Scheme 2: Two implants were vertically implanted in the lateral incisor region of the maxilla,and two short implants were vertically implanted in the posterior region of the maxilla in the bilateral second premolars.Scheme 3: Two implants were vertically implanted in the lateral incisor region of the maxilla,and four short implants were vertically implanted in the posterior region of the maxilla in the bilateral second premolars and second molars respectively.Then,three fixed implant restoration design schemes were compared and comprehensively analyzed under the inclined load direction to obtain the optimal fixed restoration design scheme.Results:(1)Regardless of the material used in the upper stent,the maximum stress peak of each model was evenly distributed in the neck region around the posterior implant and the cortical bone in the three edentulous implant fixed repair scheme designs.(2)In plan 3 design,four short implants were vertically implanted on the maxilla,showing a more ideal stress distribution.(3)The scaffold model constructed with polyether ether ketone material transferred higher stress to the implant and surrounding bone tissue near the loading area of the upper jaw;For the stent itself,the stress peak value of the upper bracket was lower than that of the titanium bracket.Among the two upper scaffolds,titanium scaffolds were more beneficial to disperse the stress distribution of implant and bone tissue.Conclusions: This study showed that the three design schemes for fixed implant repair of edentulous jaw could be applied in clinical practice.However,scheme 3 was designed as the optimal design scheme for fixed implant repair of edentulous jaw patients,which was more conducive to the long-term prognosis of fixed implant repair of edentulous jaw patients.The upper scaffold material has certain influence on the stress distribution of the implant-bone interface.