CBCT Study Of Early Bone Remodeling Following Immediate Implant Into Extraction Sockets In The Molar Region

Objective :To evaluate the ridge alterations following molar teeth extraction and immediate implantment of implants with CBCT,analyze the osteogenesis in the absence of GBR and explore possible factors that influence early bone remodeling.Methods:From January 2018 to August 2018,samples were selected in the patients who met the inclusion criteria and were implanted immediately in molar teeth extraction in the Department of Stomatology,the Fourth Affiliated Hospital of Nanchang University.After minimally invasive extraction and completely removement of the inflammatory tissue,the locking tapper implant was implanted at the same time.The autologous bone was implanted into the neck of the implant.The second surgery was performed 4 months after the operation.On the day after the implantation(T1)and on the day before the second operation(T2),CBCT was taken for all patients,and the images were processed with CS 3D Imaging software.The following data were measured:(1)Alveolar bone width(OC-OC),distance between the outside of the bone wall and the implant surface(OC-S)and thickness of the bone wall(OC-IC)at the horizontal level of 1 mm above the implant neck(L11),implant neck(L0),1mm,3mm and 5mm lower implant neck(L1、L3、L5)at T1 and T2(2)vertical distance from the alveolar ridge to the implant neck(C-R)at T1 and T2(3)vertical distance of the bone defect gap around the implant(D-R),horizontal distance of the bone defect gap around implant neck(IC-S)at T1 and T2(4)bone width of 1mm below the buccal and lingual alveolar ridge at T1.The SPSS24.0 statistical software was used to compare the bone height and bone width around the implants at T1 and T2.Results:There is a significant difference in the alveolar height(C-R)and the vertical distance(D-R)of the bone defect space,the OC-OC of L11 and L0,IC-S between T1 and T2.From L0 to L5,the amount of bone tissue changes gradually decreases.There is a greatly significant difference in the bone width,while the change of bone height was no significant difference in the extraction site with infection and non-infection.The size of the horizontal gap(IC-S)at T1 had a significant effect on the thickness of the bone wall(OC-IC)within the 4 months.Conclusion:When GBR is not taken,the bone defect around the immediate implantation area in the molar area is basically filled with new bone within 4 months and forms a good bone bond with the implant,but it will be accompanied by a decrease in the height and width of the alveolar ridge,especially around the implant neck;the implant can be deeply implanted under the bone(≥2mm)to reduce the risk of exposure to the alveolar bone due to early bone remodeling,especially for teeth with chronic inflammation.