Evaluation Of Cone Beam CT About Alveolar Ridge Preservation With Severe Periodontitis

Objectives: The effects of Alveolar Ridge Preservation(ARP)on the height and width of the alveolar ridge and the alveolar height of adjacent teeth were observed by CBCT(Cone beam Computer Tomography)as well as the effect on density and contour of the bone,compared with the site of extraction alone.Evaluate the effect of ARP with bone loss in different degree.Methods: Seventy-five teeth from 46 patients were included in the study,including 31 anterior teeth and 44 posterior teeth.The eligibility criteria:(1)the teeth with severe periodontitis should be removed;PD>6mm;AL?5mm;the alveolar bone loss is more than half of the root;FI ??;(2)at least two bone walls exist,and the remaining height of bone wall ? 3mm;(3)at least one adjacent teeth exist;(4)through periodontal initial therapy,the patient could maintain good oral status.Patients were voluntarily enrolled in the trial and signed informed consent.The exclusion criteria:(1)<18 years old;(2)in the acute infection period;(3)the history of systemic or infectious disease;(4)long-term use drugs,such as corticosteroids and bisphosphonates related to bone metabolism;(5)the history of head and neck radiotherapy;(6)in the period of pregnancy or lactation.Using random number tables,the test group is ARP after tooth extraction immediately,and the control group is the teeth of natural healing.Then the teeth are divided into group A(bone loss 5-7mm)and group B(bone loss> 7mm).In the test group,teeth are removed minimally invasive extraction,then the alveolar socket is filled Bio-Oss? bone powder and Bio-Oss? Collagen.A Bio-Gide? bio-membrane covers the bone defect area and the alveolar crest.In the end,reduce tension and suture.The teeth of control group,are minimally invasive removed,scratched,reset,and suture.According to CBCT+3D-Invivo5 dental software,we observe the change of alveolar bone.First,both buccal and lingual height of the alveolar crest on the three sagittal plane(the mesial,middle and distal)were measured before and after 6 months of removal as well as the buccolingual width of the alveolar crest below 1mm,4mm,7mm.When we measure the height,mandibular teeth treat the tangent of the lower edge of the jaw as a reference,and maxillary teeth treat the tangent of lower edge of the sinus as a reference,and the distance from alveolar ridge to the reference is measured.Second,buccal,lingual and middle height of adjacent tooth is measured from CEJ to the alveolar crest on the coronal position.Finally,evaluate the density and contour of the socket.According to Lekholm and Zarb classification,the bone is divided ?~? level.The evaluation criteria of the contour are: natural and healed well as 2';slightly sunken as 1';irregular shape as 0'.Calculate the loss of alveolar bone at different site.Using SPSS20.0 software,the independent t test and chi-square test are used to analyze the relevant data.Results: 1.There was a significant difference(P <0.05)in the absorption of height,on the mesial buccal and lingual side and the distal buccal side,as well as in the absorption of width on 1mm of the mesial sagittal alveolar crest and 1mm,4mm and 7mm at the central sagittal.In addition,there is significance(P<0.05)between group A and B.2.After tooth extraction,the height of alveolar bone was increased in the test group,while that in the control group was decreased.Compared with the control group,there were significant differences(P <0.05)in the middle and lingual side.There were many statistically significant variables in both group A and group B,which concentrated in the middle and lingual side of adjacent teeth.3.ARP has a effective impact(P<0.05)on the bone contours and density.There are more gentle contours,and more ? class bone in test group.For the group B,ARP has a significant effect on the bone contours and density.Conclusions: 1.ARP can effectively preserve the height and width of the alveolar bone,and the effect of the ARP in the teeth with severe bone defects is more significant.2.ARP is helpful to maintain the alveolar height of adjacent teeth.3.ARP is conducive to maintain the gentle shape in the edentulous area,as well as appropriate bone density,so that provide the condition for further implant and repair.