A Study Of Fenestration And Dehiscence Incidence Of Skeletal Class ? Division 1 Malocclusions With Cone Beam CT

Periodontal tissue include alveolar?cementum?gum?periodontal ligament.The healthy periodontal tissue can give sufficient supply and support during the movement of the teeth.However,periodontal defects,especially alveolar bone defects,maybe lead to excessive mobility.It is well documented that,under certain conditions,the lack of bony support during orthodontic movement can be detrimental to the health of the teeth and periodontium.With the increasing number of adult patients,the orthodontists will be faced with more and more cases with alveolar bone defects.So effective evaluation of periodontal condition related the design and carry out the treatment plan.Skeletal Class ? malocclusion is a common type in clinic,division 1 of them were classified on procumbency,deep occlusal,deep cover etc.In the course of orthodontic treatment,the shape and structure of alveolar bone determine the extent of tooth movement,especially the amount of bone on the buccal.In anterior teeth retraction process,with the root gradually close to the labial cortical bone,will increase the root exposure at the cortical bone and fenestrations and dehiscence are probably happened,or anterior fenestration and dehiscence already exist,it will aggravate the disease degree.There are few previous studies on skeletal class ? division1 malocclusions.This study aims to use cone beam CT(cone-beam computed tomography,CBCT)to investigate the incidence and sites of alveolar bone fenestration and dehiscence of skeletal class ? division 1 malocclusions of North Chinese young people.Morphology and distribution of alveolar bone defect(fenestration and dehiscence),and to provide reference for orthodontic treatment.Objective To investigate the incidence and sites of alveolar bone fenestration and dehiscence of adult skeletal class ?division 1 malocclusions with CBCT images,and to guide orthodontic clinical works.Methods 1376 CBCT images of orthodontic patients in Dalian Stomatological Hospital were randomly selected.55 of them were Skeletal Class? Division 1malocclusions.Their fenestration and dehiscence incidence were studied and statistically analyzed.To observe the incidence,morphology and distribution of bone defects(fenestration and dehiscence)in the buccal bone.Results The incidence of fenestration and incidence of Skeletal Class ?Division 1 malocclusions was 11.23% and 9.8%,the defect of alveolar is 20.58%.The fenestration most commonly affected maxillary is 16.88%.The dehiscence most commonly affected mandibular is 15.84%.The defect commonly affected mandibular.Among the fenestration,72.83% limited to the 1/3 root length,while 76.50% of the dehiscence was within 2-4mm.No significant difference was found between genders for fenestration and dehiscence.Conclusion The most incidence of bone fracture is the posterior region of Skeletal Class ? Division 1 malocclusions.Fenestration occurred more frequently in maxillary alveolar.The defect commonly affected mandibular.The incidence of defects in posterior region is lower than anterior region.Dehiscence occurred more frequently in mandibular alveolar,and the incidence of lower canines was the highest.In general,bone defects occur more in the mandible.The most incidence of defect was the first premolar in posterior areas.