Application Research Of Cast-based Guided Implant Template Of Stereoscopic Technique

With the development of a new concept of “prosthetically guidedimplantology”,dental implant technology has been greatly improved,more and morepatients and doctors perfer implant dentures.The application of surgical guide is the keytechnology.Currently surgical guide can be divided into two types according to theproduction method,these include computer-assisted design and manufacturing(CAD/CAM) based surgical guide and cast-based guided surgical guide.CAD/CAM technology uses data from CT to plan implant rehabilitation in planningsoftware.This software then transfers this presurgical plan to the surgery site usingstereolithographic drill guides according rapid prototyping technique.Accuracy ofCAD/CAM-based surgical guide is high. Special equipment is necessary.Cast-basedguided surgical guide is a combination of an analog technique done along with diagnosticwax-up, bone sounding and the use of periapical radiographs to roughly locate plantingdirection. It finished by mechanical drilling equipment manufacture.Its advantages aresimple of production process,low cost, short cycle, clinicians and technicians can easilycreate. The biggest drawback is the lack of precision, especially for complex cases, itsaccuracy and safety can not be guaranteed.Some production methods of improvedcast-based guided surgical guides have emerged.These methods still need to rely on a variety of special positioning devices and supporting software planting. Oral implantologylocator that can ues three-dimensional CT data of patients, precise positioning of theimplant three-dimensional position, and then mechanical drill to generate the surgicalguide.This method is more convenient, economical and practical.However, it is alsodependent on the special positioning equipment and effect the promotion and application.Therefore,this study was to establish a relatively simple method of surgical guides,thatdoctor or technician make use of common device to complete.It assist in guiding plantingfor some simple clinical cases.The study build stereoscopic positioning device based onstereoscopic technique, accurately transferring the three-dimensional relationship betweenthe bone and the implant simulated in software to the model, and then by mechanicaldrilling technology to produce surgical guides. Then explore the feasibility of theapplication of this surgical guide by in vitro experiments. Finally, to further validate theclinical usefulness and precision the application of this method. In order to provide a newmethod for future oral implantology guides research。Materials and methodsPart one: Stereoscopic positioning device is builded according to the size and form ofdental arch.This device consists of an arcuate base,parallel positioned columns,retentiveapophysis and radiological points.It accepted CBCT scanning,the date were reconstructedthree-dimensional model.Meanwhile,it establish a new methods of cast-based guidedsurgical guide Based on stereoscopic technique.Part two:Turn the mandibular epoxy resin model.According to production process ofthe surgical guides from part one,maxillary model with radiation guide was accepted CTscanning,the date were imported in planting software to reconstruct three-dimensionalmodel and simulate implantation.The three-dimensional models of stereoscopicpositioning device from CBCT and CT were registrated with each other by radiologicalpoints.The spatial relationship of implants and decices was measured.clinometeraccurately transfer the three-dimensional relationship between the bone and the implantsimulated in software to the model, and then by bench drill to puch for producing surgicalguides.Under the guidance of the surgical guides,12implants were implanted in jaw model, comparing actual and virtual implant differences in the three-dimensional directionafter registration of pre-and post-operative CT images in Geomagic software。Part three:17patients with dentition defect were randomly selected, surgicaltemplate were fabricated.In total,32implants were inserted. Comparing actual and virtualimplant implant differences in the three-dimensional direction after registration of pre-andpost-operative CT images in Geomagic software。Results and conclusions:1.A new methods of cast-based guided surgical guide based on stereoscopic techniquewas established.Generic stereoscopic positioning device was successfully constructed.Itcan be used repeatedly, eliminating the tedious of the dual CT scan, reducing the time andmoney costs.This method:the radiation guides with the stereoscopic positioning devicewas generated.It was located on the mouth of the patient after the CT scanning.The datewere imported in SimPlant software to reconstruct three-dimensional model and simulateimplantation.The three-dimensional models of stereoscopic positioning device fromCBCT and CT were registrated with each other by radiological points.Three-dimensionalmodel as a reference to measure implant site and relative angel.In vitro,it can transferthree-dimensional relationship between the bone and the implants to the model by usingthe cable universal observation platform and angle measuring instrument.The radiationguide was transfered into final surgical guide by laser bench,or bench drill to puch inmodel and vacuum membrane technique forming surgical guide.2. Measurements deviation between planned implants and actual implants in vitro.Theentry deviations of the implant was0.97±0.24mm (95%CI:0.81-1.12mm),and apicaldeviation was1.44±0.25mm (95%CI:1.28-160mm), and the axis deviation was5.01±1.76°(95%CI:3.89-6.12°).Although it produce a certain deviation, the deviationvalue within the range of deviation of CAD/CAM guides (entry deviations:95%CI:0.76-1.22mm, apical deviation:95%CI:1.26-2.0mm,axis deviation:95%CI:3.94°-6.58°,). This surgical guide with high precision can guide planting。3.In clinical experimental,the entry deviations of the implant was1.10±0.25mm (95%CI:0.61-1.59mm),and apical deviation was1.76±0.38mm（95%CI:1.21–2.25mm）, and the axis deviation was5.75±2.62°（95%CI:3.01°–8.21°）.The deviation value is slightlylarger than the CAD/CAM guides.These guides still played an important role in accuratepositioning for simple case.The production of surgical guides of this study issimple,economical and practical, with good prospects for clinical application.