Flapless Implant Placement using Drills versus Drills plus Screw Expanders

Abstract

The present study was conducted on 14 implants inserted in two male patients seeking implant placement of their lost teeth selected from outpatient clinic; Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Ain shams University. The aim of current study was to evaluatethe accuracy of successful implant placement using drills alone and drills with screw expanders and to compare the outcome obtained radiographically. Preoperative diagnosis and evaluation of the patients was carried out through a combination of clinical and radiographic examination. Clinical examination included intraoral examination of Inter arch space, examination of the ridge shape and volume. Preoperative CBCT were used to evaluate bone height and shape of the edentulous area of the ridge. Fabrications of surgical guide was done through different steps as following; fabrication of radiopaque template by duplication of the acrylic denture using X-resin material, then all patients were scanned preoperatively using CBCT machine while wearing the RO templates while biting on cotton pellets to ensure maximum compression of soft tissue mucosa, then segmentation, threshold-processing of CBCT data, virtual implant placement and design of the surgical guide were done usingOnDemand software program and fabricated by In2Guide by 3D Vision of Cybermed Inc. Patients were randomly divided into two groups: • GroupA (control): included seven implants placed after flapless and computer guided surgery technique using usual drills only. • GroupB (study): included seven implants placed after flapless and computer guided surgical technique using initial drill only plus screw expanders. Implant placement was performed under local anesthesia, in minor surgical clinic; surgical guide was placed with cotton pellets on the occlusal surface and patient was asked to bite against the opposing teeth or denture, then the surgical guide was secured in place using mono-cortical screws then custom made metal sleeves were placed in their fitting hubs on the surgical guide template, and full sequence drillings preformed using custom made drill guide keys until the proper implant diameter was reached, after the process was finished, the fixing screws were unscrewed and the surgical guide was removed, then the cover screws were placed. Postoperative clinical evaluation of these patients were undertaken on second, fifth, and seventh postoperative day in order to check bleeding, pain, swelling, and infection. Then at one and three months postoperatively, the patients were recalled six months later for fabrication of final restorations. In all cases immediate postoperative CBCT scans, directly performed after surgery, with the same parameters of preoperative scans for comparative analysis, the CT scan DICOM images of pre and post-operative scans were then imported into proprietary software programs, all implants were identified in the resultant post-operative CTs and virtual implants were super-positioned on their images, the measurement of distances between the planned and actual position of the implants and/ or implant angle deviations had to be clearly described, error at the entry and the apex and the error in the height were measured in mm while the angular deviation was measured in degrees. Radiographic evaluation was done using standardized periapical digital radiograph and readings were obtained at the following intervals:0,1, 3,and 6 months postoperatively to measure the amount of cortical bone loss and radio density of peri-implant bone in following intervals. Reviewing the results regard to region at the degree differences ( angular deviation) there was no differences in accuracy between two groups, also there was no significant difference in accuracy between two groups regards to x and y directions coronaly or apically. The significant differences were in z direction between two groups both coronal and apical and in the region coronaly supporting the use of expanders more than traditional drills. The results of this study showed that the application of screw bone expanders resulted in statistically high significant increase in the radiodensity at three and six months postoperatively compared to the control group. Also there were statistically highly significant differences; between control and study group regards changes in vertical bone loss from immediate till post-operative at one, three and six months, the mean of bone loss for study group was lower than that for control group.