Analysis Of The Changes Of The Arch Symmetry In The Patients With Mandible Deviation Before And After The Treatment With Three-dimensional Scanning Technique

Objective: Measure the arch width of the mandible deviation before and after orthodontic treatment by using three-dimensional scanning technology.To analyzed and compared the changes of the symmetry of the arch of the patients before and after treatment.Methods:To collect and sort out 214 of the patients with mandible deviation who visit Shenyang Stomatology Hospital from May 2008 to February 2014,15 patients who met the screening criteria were selected as the subjects of the retrospective study.There are 3males and 12 females,aged 12-17 years old,the average age of 14.3 years,the average duration of 22.8 months,chin left 7 cases,right 8 cases.Inclusion criteria : Permanent dentition,teeth with row full(except the third molars)were Angle Class III or Skeletal III,sagittal molar to close in relationship were mesial,one side posterior teeth were crossbite,anterior teeth were on the edge or crossbite,dentition mild or moderate crowding.The front view: facial asymmetry,chin oblique over 2mm,intercuspal occlusion and mandibular postural position mandible are deflected condition.Periodontal health.Patients with no facial tumor,no trauma history,no condylar benign hypertrophy,temporomandibular joint infection history,no other cause of severe skeletal malformation of the maxillofacial syndrome,no orthodontic treatment history and other medical history.All of the subjects were using sodium alginate impression material impression,anhydrite perfusion model,and model of finishing standby.Respectively 3shape 3D scanner in maximum intercuspal position scanning in patients with preoperative and postoperative model and obtain the digital dental model,definition of mandibular deviation in the direction of the side for the deviation side,on the side is deviated side,biased side of the dental arch width minus deviation from the side of the arch width and analysis of the dental arch before and after treatment before,middle and posterior segment of the dental arch symmetry.The changes of mandible deviation treatment dental arch symmetry will be analyzed and compared by paired t test statistical analysis of before and after treatment of dental arch before,during and after the symmetry change.Results:All patients with mandibular teeth were aligned,arch,symmetry,anterior teeth overbite and overjet,molar teeth of neutral between upper and lower midline alignment,but did not correct facial asymmetrical.Patients before and after treatment of dental models were scanned by three-dimensional models analysis,obtained the results:Before treatment patients with maxillary anterior and posterior segment arch side width and bias were greater than the deviated side(P < 0.05),anterior dental arch asymmetry differences minimum arch middle times,largest segment of the posterior arch asymmetry;after treatment of maxillary arch asymmetry differences decreased obviously,changes of the dental arch anterior difference minimum dental arch in the middle of the difference changes times,variation of dental arch segment difference.There was no statistical significance(P>0.05)in the treatment of mandibular dental arch before and after treatment.Conclusion: The asymmetry of dental patients before treatment of maxillary arch has obvious asymmetry,the dental arch asymmetry differences in orthodontic treatment of small,maxillary dental arch symmetry.