Applying Cbct To Study The Effects Of Apical And Root Hard Tissue During Orthodontic Traction Of Impacted Maxillary Canines

Impacted maxillary canines refers to canines ambushed in the mucosaor bone, and thus can’t erupt to the normal position of the dental arch, dueto blocked by jaw, adjacent teeth or fibrous tissue. For patients with greatinfluences on oral normal function and appearance, is one of orthodonticclinical difficult diseases. Many scholars at home and abroad usedtraditional radiological methods to study impacted canine in the past. Withthe rapid development of computer image technology, cone beamcomputed tomography becomes the effective means on studying ofimpacted canine. Orthodontic treatment mainly through the orthodonticforce is used to the teeth and periodontal tissue, causing a series ofbiological reactions, resulting in alveolar bone alterations to achieve thepurpose of tooth movement. Studying on the effects of apical and roothard tissue during different orthodontic force on impacted maxillarycanines, reference for guiding the orthodontic clinicians to grasp and usecorrectly orthodontic force.The paper is divided into two parts:The first part: Clinical researching of maxillary impacted canines inthe region of ChongqingObjective: Investigate the prevalence of malocclusion deformitypatient with maxillary impacted canine in the region of Chongqing, toanalysis the impacted status. Methods: During July2010to August2011,collecting themalocclusion deformity cases treated in Department of orthodontics,College of Stomatology, Chongqing Medical University and filmed conebeam CT in the radiology Dept, to statistics the prevalence situation ofmaxillary impacted canine.Results: During July2010to August2011, malocclusion patientswith a total of3170cases，treated in Department of orthodontics,College of Stomatology, Chongqing Medical University and filmed conebeam CT in the radiology Dept, in which of maxillary impacted canine52cases, male28cases, female34cases.Labial impaction32cases,15casesof palatal impaction, horizontal impacted5cases.Conclusion: The rate of the maxillary impacted canine prevalence is1.6%in the region of Chongqing, the rate of female prevalence is higherthan male, of which the most common is labial impaction.The second part: Applying cone beam computed tomography(CBCT)to study the effects of apical and root hard tissue during orthodontictraction of impacted maxillary canines.Objective: Applying cone beam computed tomography(CBCT) tostudy the changes of apical and root hard tissue during differentorthodontic force on impacted maxillary canines, reference for the clinicaltreatment of impacted canine.Methods: Twenty cases with straight wire appliance orthodontictreatment of impacted maxillary canine labial ambush were selected,randomly divided into2groups of10people. Using the chain rubber ringto apply respectively forces of60g,150g in the direction of major axis oftooth body to maxillary impacted canines, from the beginning of Surgicalexposure surgery until the impacted teeth discharged fully into the arch, anaverage of10months. Using CBCT to analysis the changes of Maxillary canine root length and bone density around root before and after treatment,measurement data using SPSS16.0software paired t-test.Results: There were no significant differences on the tooth rootlength, bone density around the root when adopting60g of traction forceto move wholly toward major axis of tooth body compared with theprevious (P>0.05).But there was significant difference on the tooth rootlength, bone density around the root when adopting150g of traction forceto move wholly toward major axis of tooth body compared with theprevious (P<0.05).Conclusion: When the direction of traction is consistent with themajor axis of the tooth, tends to the overall mobile, periodontal tissuestress are more evenly distributed, beneficial to its traction. Smallertraction force value in favor of impacted canines traction.