| Objective:To analyze the occlusion and condylar three-dimensionalposition changes between centric relation(CR) and maximumintercuspation(MI) in patients with mandibular deviation,to analyze theclinical manifestations and related factors，and to discuss its influence onorthodontic diagnosis and treatments of dental maxillofacial deformities.Methods:Fifty patients with mandibular deviation were taken asexperimental group and fifty patients with non-deviation as control grouprandomly.Occlusal records of CR position and MI position were acquiredby occlusal record wax in mouth and then transfered to AD2articulator bythe bite fork、facebow,and the wax record, the overbite of anterior teeth atCR or MI position and overjet of anterior teeth at CR or MI position weremeasured and compared respectively;occlusal interferences of CR positionwere recorded.Condylar positions of CR and MI were recorded respectively by measures condyle displacement(MCD), and the amount ofdisplacement of CR-MI in vertical、sagittal and transverse plane werecalculated, it was recognized as CR-MI discrepancy with reference to thestandard as follows:amount of displacement of CR-MI in vertical or sagittalgreater than or equal to1.0millimeter or amount of displacement of CR-MIin transverse plane greater than or equal to0.5millimeter,and the CR-MIdiscrepancy frequency were counted,percentages of occlusal interferencesand CR-MI discrepancy,as well as the amount of displacement of CR-MIof experiment group were compared. with control group, CR-MIdiscrepancy and the amount of displacement of CR-MI was comparedbetween deviated and non-deviated side、 temporomandibular jointdisorder(TMD) group and non-TMD group、male and female in experimentgroup,and related factors of CR-MI discrepancy were analyzed.Results:(1)Overbite of CR was less than overbite of MI,overjet of CRwas greater than overjet of MI,and there was statisticalsignificance(P<0.01);Percentages of occlusion interferences betweenexperimental and control group was90%and72%respectively withstatistical differences(χ2=5.263,P=0.022);and the occlusion interferences ofboth groups were located at the posterior teeth,accounting for84%and68%respectively;percentages of occlusion interferences between deviatedand non-deviated side in experiment group were similarly46%and44%respectively;(3)Percentages of CR-MI discrepancy between experimental and control group was86%and12%respectively with statisticaldifferences(χ2=54.782,P=0.000);amount of displacement of CR-MI ofexperiment were greater than control group with statisticaldifferences(P<0.01);in experimental group,there was no significantdifference in the percentage of CR-MI discrepancy and the amount ofdisplacement of CR-MI between deviated and non-deviatedside(P>0.05);(4)There was no significant difference between TMD groupand non-TMD group of experiment group in the percentage of CR-MIdiscrepancy and the amount of displacement of CR-MI(P>0.05); Therewas no significant difference between male and female of experimentgroup in the percentage of CR-MI discrepancy and the amount ofdisplacement of CR-MI(P>0.05);There was positive correlation betweenCR-MI transverse shift and CR-MI overbite difference、CR-MI overjetdifference;There was no correlation between the amount of displacementof CR-MI and amount of displacement of mandible.Conclusions:Patients with mandibular deviation show a highertendency to suffer CR-MI discrepancy,and the occlusion between CR andMI was not consistent,which was possibly caused by occlusalinterference at CR position.For mandibular deviation people,occlusionchanges by clinical observation could not stand for condylar positionchanges in three-dimensional direction,however,we should analyze the realocclusion and CR-MI discrepancy by transferring CR occlusion relationship to articulator,which is the basis of making right diagnosis andplan.We should pay attention to eliminate the influence of occlusalinterference and to vertical control,and to establish occlusion at CRposition,which facilitate the stability of treatment effect. |
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