Computer Aided Full Arch Restoration by Means of One-Piece Implants and Stackable Guide: A Technical Note

This technical note aims to present a recently developed computer-guided protocol characterized by titanium-reinforced stackable surgical guides during post-extractive implant placement and subsequent immediate loading. A full maxillary edentulism was rehabilitated with one-piece implants, starting from a pre-existing removable denture. 3D digital scans of the removable denture and upper and lower arches were performed. On this basis, a prototype with ideal esthetic and functional outcomes was realized and replicated into a custom-made radiological stent with markers. The superimposition of STL and DICOM files allowed virtual planning of one-piece implants in the ideal prosthetically driven position. The stackable guides, composed of a fixed base template and additional removable components, were then realized. The fixed template, initially secured with anchor pins to the bone, was no longer removed. The removable components, which were screwed to the base template, were used to perform implant surgery and immediate prosthetic loading. No surgical complications occurred, the implants achieved a minimum insertion torque of 35 Ncm, and immediate prosthetic loading was performed. The base template allowed for the maintenance of a fixed reference during the entire workflow, improving the transition between the digital project, the surgical procedure, and the prosthetic rehabilitation.

Accuracy of Palatal Orthodontic Mini-Implants Placed Using Fully Digital Planned Insertion Guides: A Cadaver Study

Digital workflows have become integral in orthodontic diagnosis and therapy, reducing risk factors and chair time with one-visit protocols. This study assessed the transfer accuracy of fully digital planned insertion guides for orthodontic mini-implants (OMIs) compared with freehanded insertion. Cone-beam computed tomography (CBCT) datasets and intraoral surface scans of 32 cadaver maxillae were used to place 64 miniscrews in the anterior palate. Three groups were formed, two using printed insertion guides (A and B) and one with freehand insertion (C). Group A used commercially available customized surgical templates and Group B in-house planned and fabricated insertion guides. Postoperative CBCT datasets were superimposed with the planning model, and accuracy measurements were performed using orthodontic software. Statistical differences were found for transverse angular deviations (4.81° in A vs. 12.66° in B and 5.02° in C, p = 0.003) and sagittal angular deviations (2.26° in A vs. 2.20° in B and 5.34° in C, p = 0.007). However, accurate insertion depth was not achieved in either guide group; Group A insertion was too shallow (-0.17 mm), whereas Group B insertion was deeper (+0.65 mm) than planned. Outsourcing the planning and fabrication of computer-aided design and computer-aided manufacturing insertion guides may be beneficial for certain indications; particularly, in this study, commercial templates demonstrated superior accuracy than our in-house-fabricated insertion guides.

Applications of CAD/CAM Technology for Craniofacial Implants Placement and Manufacturing of Auricular Prostheses-Systematic Review

This systematic review was aimed at gathering the clinical and technical applications of CAD/CAM technology for craniofacial implant placement and processing of auricular prostheses based on clinical cases. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, an electronic data search was performed. Human clinical studies utilizing digital planning, designing, and printing systems for craniofacial implant placement and processing of auricular prostheses for prosthetic rehabilitation of auricular defects were included. Following a data search, a total of 36 clinical human studies were included, which were digitally planned and executed through various virtual software to rehabilitate auricular defects. Preoperative data were collected mainly through computed tomography scans (CT scans) (55 cases); meanwhile, the most common laser scanners were the 3dMDface System (3dMD LLC, Atlanta, Georgia, USA) (6 cases) and the 3 Shape scanner (3 Shape, Copenhagen, Denmark) (6 cases). The most common digital design software are Mimics Software (Mimics Innovation Suite, Materialize, Leuven, Belgium) (18 cases), Freeform software (Freeform, NC, USA) (13 cases), and 3 Shape software (3 Shape, Copenhagen, Denmark) (12 cases). Surgical templates were designed and utilized in 35 cases to place 88 craniofacial implants in auricular defect areas. The most common craniofacial implants were Vistafix craniofacial implants (Entific Medical Systems, Goteborg, Sweden) in 22 cases. A surgical navigation system was used to place 20 craniofacial implants in the mastoid bone. Digital applications of CAD/CAM technology include, but are not limited to, study models, mirrored replicas of intact ears, molds, retentive attachments, customized implants, substructures, and silicone prostheses. The included studies demonstrated a predictable clinical outcome, reduced the patient's visits, and completed the prosthetic rehabilitation in reasonable time and at reasonable cost. However, equipment costs and trained technical staff were highlighted as possible limitations to the use of CAD/CAM systems.

[The role of 3D technology in the support of mechanical circulation therapy.]

INTRODUCTION

Successful mechanical circulatory support is influenced by various factors, which are difficult or impossible to control. For ideal functioning of the left ventricular assist device inflow-cannula, its axis should be close to parallel with the septum, facing the mitral valve within the left ventricle. Numerous international publications discuss that deviation from optimal implantation can lead to inadequate functioning and serious complications.

OBJECTIVE

Our objective was to developing a method, which, using 3D technology, anatomical and hydrodynamic data, makes optimal surgical implantation of the left ventricular assist device possible.

METHOD

Data of 57 patients, receiving mechanical circulatory support at Semmelweis University, Heart and Vascular Center, were analyzed retrospectively. Results of operations performed with the patented novel navigation device (exoskeleton) were compared with results of operations performed conventionally, without navigation (control group). Following pairing based on estimated participation probability, postoperative data of 7-7 patients were compared. DICOM files from CT angiography images were used to create virtual geometries of individual hearts. Optimal inflow-cannula angle was determined through hydrodynamic simulation. Exoskeletons were printed using synthetic resin suitable for surgical purposes. Exoskeleton templates guided punch knife positioning and inflow-cannula implantation.

RESULTS

Evaluation of postoperative CT angiography images showed that the angle between inflow-cannula and interventricular septum significantly differed in the exoskeleton and control groups (10.13° ± 2.69° vs. 22.87° ± 12.38°, p = 0.0208). Hydrodynamic tests found significantly lower turbulence in the exoskeleton group. Simulated turbulent kinetic energy was significantly lower in the exoskeleton group, which was 11.7 m2/s2 ± 9.39 m2/s2 vs. 49.59 m2/s2 ± 7.61 m2/s2 on average.

CONCLUSION

The results suggest left ventricular assist device implantation with patented exoskeleton to be a standardizable, safe and effective method. Preliminary results suggest, that the method may facilitate individualized care, reduce surgical time and incidence of serious complications. Orv Hetil. 2023; 164(26): 1026-1033.

Can computer-guided surgery help orthodontics in miniscrew insertion and corticotomies? A narrative review

Orthodontics has considerably increased the use of technology combined with surgery as a tool to improve dental movements in terms of predictability, acceleration of movement, and fewer side effects. To achieve these goals miniscrews and corticotomy were introduced. The digital workflow permits an increase in the accuracy of surgical and orthodontic setups. The tool that transfers the information is the CAD/CAM (Computer-Aided Design/ Computer-Aided Manufacturing) template. The aim of this review is to illustrate the use of computer-guided surgery in orthodontics regarding miniscrews and piezocision. The search strategy was a combination of Medical Subject Headings (Mesh) and free text words for PubMed. A total of 27 articles were included in this review: 16 concerned miniscrews and 11 concerned corticotomy. The current need for faster treatments, the improved systems of anchorage, and the evolution of imaging technologies require operators to be knowledgeable of the digital workflow. CAD/CAM templates allow greater precision and predictability of miniscrew insertion even if in the hands of less experienced clinicians and permit a better orientation and depth of the cortical incision. In conclusion, digital planning makes surgery faster and easier and allows for the identification and correction of any potential problem before the procedure.

PRESS and Piezo MicroSurgery (Bony Lid): A Seven Year Evolution in a Residency Program Part 2: PRESS- defined site location

INTRODUCTION

Treatment of a failing endodontic procedure via microsurgical revision presents better outcomes due, in part, to the integration of the Surgical Operating Microscope (SOM) and CBCT into clinical practice. But challenges still remain with respect to the operational locations and the techniques required to address them. Posterior sites, with substantial cortical plate thicknesses and sensitive anatomy, present the dichotomy of visualization versus post-surgical regeneration of bone. The bony lid technique bridges the gap between these two concepts, and the application of Piezosurgery renders a precise and biocompatible osseous incision. The purpose of this paper is to outline, through Case reports, the progression of Piezo-Guided surgery in a resident setting.

METHODS

The first two evolutions of the technique utilized a surgeon-defined method for site location. This third and final evolution utilizes a digital workflow to virtually plan the surgical procedure, integrating STL and DICOM files to create 3-dimensional guides with exacting resection locations, levels, and angles. Export of the virtually planned guide in post-production generates the Precision Endodontic Surgical Stent (PRESS) to accurately define the site location and parameters of the procedure. All surgeries were executed using the Piezosurgical method with increasing levels of guidance and precision throughout the evolution process.

RESULTS

Each step in the technique implementation enabled the resident to assimilate a new technique and skill set while maintaining bone architecture and minimizing volume loss post-operatively. The patient benefits were an increase in intra-operative safety and post-operative comfort. The resident benefits were accelerated regeneration timetables, increase in the confidence level of the resident and number of scheduled posterior surgical procedures.

CONCLUSIONS

The progression from crude on-site measurements to elegant and precise surgical guides enabled the access and manipulations of difficult surgical sites without compromising visibility, post-operative osseous regeneration, or patient comfort.

3D-printed, patient-specific DIEP flap templates for preoperative planning in breast reconstruction: a prospective case series

Background

Modern imaging technologies, such as computed tomographic angiography (CTA), can be useful for preoperative assessment in deep inferior epigastric artery perforator (DIEP) flap surgery. Planning perforator flap design can lead to improved surgical efficiency. However, current imaging modalities are limited by being displayed on a two-dimensional (2D) surface. In contrast, a 3D-printed model provides tactile feedback that facilitates superior understanding. Hence, we have 3D-printed patient-specific deep inferior epigastric artery perforator (DIEP) templates, in an affordable and convenient manner, for preoperative planning.

Methods

Twenty consecutive patients undergoing 25 immediate or delayed post-mastectomy autologous breast reconstruction with DIEP or muscle-sparing transverse rectus abdominis (MS-TRAM) flaps are recruited prospectively. Using free, open-source softwares (3D Slicer, Autodesk MeshMixer, and Cura) and desktop 3D printers (Ultimaker 3E and Moment), we created a template based on a patient's abdominal wall anatomy from CTA, with holes and lines indicating the position of perforators, their intramuscular course and the DIEA pedicle.

Results

The mean age of patients was 52 [38-67]. There were 15 immediate and 10 delayed reconstructions. 3D printing time took mean 18 hours and 123.7 g of plastic filament, which calculates to a mean material cost of AUD 8.25. DIEP templates accurately identified the perforators and reduced intraoperative perforator identification by 7.29 minutes (P=0.02). However, the intramuscular dissection time was not affected (P=0.34). Surgeons found the template useful for preoperative marking (8.6/10) and planning (7.9/10), but not for intramuscular dissection (5.9/10). There were no immediate flap-related complications.

Conclusions

Our 3D-printed, patient-specific DIEP template is accurate, significantly reduces intraoperative perforator identification time and, hence, may be a useful tool for preoperative planning in autologous breast reconstruction.

Use of computer-aided three-dimensional prototyping to surgically assist in tooth autotransplantation

Autotransplantation is a surgical technique in which a donor tooth belonging to the same individual is repositioned into a surgically prepared socket or site of previous tooth extraction. It is beneficial in patients with teeth affected by agenesis, trauma, significant caries, and in teeth in a non-restorable condition or prognostically poor due to other pathology. It is particularly useful in paediatric patients, as properly transplanted teeth have a vital periodontium that allows for continuous growth and functional adaptation leading to preservation of the alveolar ridge. Technological advances in rapid prototyping combined with three-dimensional (3D) computed tomography (CT) have the ability to revolutionise autotransplantation. Preoperative planning for atraumatic extraction of the donor tooth and precise preparation of the recipient site with a rapid prototyped surgical template of the donor tooth considerably reduces the extra-alveolar time, and also reduces manipulation of the root sheath and periodontal ligament, and related trauma. This case series demonstrates the efficient and successful autotransplantation of various types of teeth with the use of a rapid prototyped surgical template produced from 3D CT. The use of this technology is expected to refine the surgical technique and improve treatment outcomes.

Comparison of positioning accuracy between two different implant systems using mucosa-supported surgical templates: a retrospective clinical study

Although guided implant surgery is widely practiced, clinical studies examining the differences in accuracy between implanting systems that use the same surgical guide are currently lacking. This study aimed to evaluate and compare the effects of different dental implanting systems on positioning accuracy using a uniform type of stereolithographic surgical guide to account for cumulative errors in guide production. One hundred BEGO Semados® S implants (Group A) and ninety-one NobelActive® implants (Group B) were inserted into patients using the same type of guide. The accuracy was assessed by matching the preoperative and postoperative cone-beam computed tomography (CBCT). The implant shoulder, tip, depth and angular deviation were registered. Statistically significant differences between groups were  determined using student's t-test, bivariate correlation test and generalized estimating equation. The angular deviation was 3.16±1.74° in Group A and 2.58±1.41° in Group B (P=0.013 ); the depth deviation was 0.44±0.23mm in GroupA and 0.51±0.22mm in Group B (P=0.032). In terms of vertical accuracy, the Bego implant system is superior to the Nobel implant system using the same type of surgical guide, while the angle accuracy is opposite. Therefore, it is important to control the depth when using the template guided surgery in Nobel implant system. Similarly, angle control should be emphasized in Bego implant system. Measurements of the deviations provide the basis for a clinical reference that will be useful in preoperative analysis for improvement of the safety and accuracy of guided implant surgical procedures.

The development of computer-aided patient-specific template design software for 3D printing in cranio-maxillofacial surgery

BACKGROUND

The patient-specific templates for osteotomy often have complex surface features. Using current commercial software to design such templates is quite complicated, tedious and unrepeatable.

AIMS

In this study, a novel surgical planning system for oral and maxillofacial surgery named EasyTemplate is developed, aiming to help doctors shorten the modelling time and assure the reliability in template design.

MATERIALS & METHODS

In the simplified design process of an osteotomy guide, the main template can be formed efficiently using a surface offsetting algorithm, which is based on isosurface extraction and oriented bounding box. Thereafter, the cutting grooves can be generated automatically.

RESULTS

A complicated surgical guide could be built accurately in about 10 min. Clinical orthognathic cases were conducted successfully using osteotomy and repositioning templates designed by EasyTemplate.

DISCUSSION

Compared with commercially available softwares, higher efficiency and simpler design process were achieved, moreover, the time cost is one-third or even less.

CONCLUSION

EasyTemplate can be a useful alternative to traditional softwares. This software allows the auto-generation algorithm which helps avoid a tedious modeling process while providing basic shapes for designers.

Concept description and accuracy evaluation of a moldable surgical targeting system

Purpose: We explain our concept for customization of a guidance instrument, present a prototype, and describe a set of experiments to evaluate its positioning and drilling accuracy.

Methods: Our concept is characterized by the use of bone cement, which enables fixation of a specific configuration for each individual surgical template. This well-established medical product was selected to ensure future intraoperative fabrication of the template under sterile conditions. For customization, a manually operated alignment device is proposed that temporary defines the planned trajectory until the bone cement is hardened. Experiments (n=10) with half-skull phantoms were performed. Analysis of accuracy comprises targeting validations and experiments including drilling in bone substitutes.

Results: The resulting mean positioning error was found to be 0.41±0.30  mm at the level of the target point whereas drilling was possible with a mean accuracy of 0.35±0.30  mm.

Conclusion: We proposed a cost-effective, easy-to-use approach for accurate instrument guidance that enables template fabrication under sterile conditions. The utilization of bone cement was proven to fulfill the demands of an easy, quick, and prospectively intraoperatively doable customization. We could demonstrate sufficient accuracy for many surgical applications, e.g., in neurosurgery. The system in this early development stage already outperforms conventional stereotactic frames and image-guided surgery systems in terms of targeting accuracy.

[Clinical application and accuracy analysis of occlusion-guided functional mandibular reconstruction]

Objective

To investigate the influence of the design and application of novel surgical template on the accuracy of reconstructed mandibula and implant position in occlusion-guided functional mandibular reconstruction, so as to provide guidance for clinical treatment.

Methods

Between January 2017 and May 2019, 11 patients with segmental mandible defects were treated, including 8 males and 3 females with an average age of 31.8 years (range, 19-45 years). There were 6 cases of ameloblastoma, 3 cases of keratocystic tumor, and 2 cases of ossifying fibroma. According to Urken classification of mandible defects, there were 1 case of CRB, 4 cases of RB, 2 cases of RBS, and 4 cases of SB. According to the occlusion relationship, a novel surgical template with the reconstruction titanium plate screws and implants drill-guided information was designed and manufactured. With the help of the novel surgical template, the "one and a half" fibula reconstruction mode was used for jaw functional reconstruction, and the implant supported denture was finally completed. The postoperative CT at 1 week were collected to analyze the morphology of the preoperative virtual design jaw and postoperative jaw. The coincidence of fibular reconstructed mandible (fibular upper barrel, fibular reconstructed ramus and condyle, and whole mandible) and implant in mandible were calculated. When the coincidence was less than 80%, it was considered that the deviation was obvious. Oral panoramic X-ray film and cone beam CT were examined at 6 months after operation to evaluate the osseointegration before implant repair.

Results

None of the 11 flaps had postoperative vascular crisis. One flap occurred necrosis at 1 month after reconstruction combined with 3 implants failed, and had been removed at 6 months after reconstructed surgery; the others had no flap necrosis. One week postoperatively, the coincidence of the fibular upper barrel was 87.55%±3.08%, the whole mandible was 82.68%±5.94%, and the implant in mandible was 88.00%, with significant differences ( t=8.131, P=0.000; t=2.118, P=0.046; Z=4.070, P=0.000) when compared to 80%, respectively. The fibular reconstructed ramus and condyle was 77.82%±3.54%, with no significant difference ( t=-2.042, P=0.068) when compared to 80%. Six months postoperatively, oral panoramic X-ray film and cone beam CT showed that all 22 implants achieved osseointegration and the palatal mucosa transplantation was performed, then finally completed the denture rehabilitation at 6-9 months after operation. All patients were satisfied with their postoperative appearance.

Conclusion

The novel surgical template can guarantee the accuracy of functional mandible reconstruction guided by occlusal guidance, and ultimately achieve the beautiful contour of jaw and occlusal function reconstruction, and improve the patient's life quality.

Guided Osteotomy and Guided Autotransplantation for Treatment of Severely Impacted Teeth: A Proof-of-Concept Report

INTRODUCTION

The aim was to present a novel surgical technique using virtually preplanned 3-dimensional (3D)-printed templates for guided osteotomies. These were to ensure atraumatic uncovering of a severely impacted donor tooth including guided drilling of the recipient alveolus followed by a secure autotransplantation procedure.

METHODS

This report presents an autotransplantation procedure of a 14-year-old patient with a severely impacted second premolar and extensive contact to the roots of the adjacent teeth and the inferior alveolar nerve. Autotransplantation of the impacted premolar was virtually performed using modified methods from guided implant surgery in order to prefabricate 3D-printed templates with the aid of a fully digital workflow.

RESULTS

Satisfactory treatment could be achieved using surgical templates for guided osteotomies of the surgical access, guided drilling of the recipient site, and occlusal reference template ensuring autotransplantation in the appropriate 3D location of the graft. An atraumatic approach could be ensured with an extraoral time of 46 seconds by 1 fitting attempt; no injuries or altered sensation of the inferior alveolar nerve were present. A vital natural tooth could be observed.

CONCLUSIONS

This innovative technique uses for the first time a fully implemented digital workflow for guided osteotomies, guided drilling, and guided autotransplantation of a severely impacted tooth. 3D-printed templates could ensure a guided atraumatic approach and facilitate highly complex treatments by virtually implementing recommended guidelines in future autotransplantations.

Computer-guided palatal canine disimpaction: a technical note

AIM

To present a minimally invasive approach to solve the impaction of palatal canines using computer-guided orthodontic miniscrews.

MATERIALS AND METHODS

Miniscrew-supported appliances for palatal canine disimpaction are performed with CAD/CAM technology. With adequate software, it is possible to match the STL files of the dental arch with the DICOM images of the maxilla, previously transformed into STL files. The ideal points for miniscrew insertion can be identified on the STL 3D model file on the basis of the width and thickness of the palatal vault. A software application allows for the design of the surgical guide, which is printed using a 3D printer. The virtual position of the planned miniscrews is transferred onto a printed dental cast on which the orthodontic device is realized. On the day of surgery, both the surgical guide and the orthodontic appliance are ready for use.

RESULTS

Miniscrew insertion and palatal canine disimpaction can be achieved in one surgical procedure.

CONCLUSION

The use of computer-guided skeletal anchorage allows for both the reduction of the biomechanical side effects typical of conventional treatment and the risk of damaging adjacent anatomical structures, increasing the effectiveness of treatment. Controlled clinical trials are necessary to evaluate more fully any advantages of this minimally invasive technique.

Improved accuracy of hemimandibular reconstructions involving the condyle by utilizing hydroformed reconstruction plates rather than hand-bent stock plates

BACKGROUND

Computer-aided design/computer-aided manufacturing (CAD/CAM) surgical templates allow precise mandibular reconstructive surgery. However, their clinical accuracy is limited by manual plate bending. Digitally hydroformed plates maintain a digital workstream in virtual planning.

METHODS

Twelve patients with Brown's class IIc mandibular defects were randomized into two groups: group I (experimental), the reconstruction plate was digitally hydroformed, and group II (control), surgeries were performed CAD/CAM guided with the reconstruction plate manually prebent. The linear and angular deviations of reconstruction outcomes were compared to surgical simulation in both groups.

RESULTS

The mean linear and angular deviations of middle and posterior segments were 2.14 ± 0.79 mm, 3.71 ± 0.95 mm, 8.73° ± 1.91°, and 9.06° ± 0.96° in group I and 4.31 ± 0.78 mm, 6.74 ± 1.40 mm, 16.35° ± 0.72°, and 31.48° ± 3.38° in group II, respectively. Measurements in group I were significantly lower than group II (P < .005).

CONCLUSION

Digital hydroforming for plate prebent is a reliable method that helps improving the clinical accuracy of CAD/CAM-guided mandibular reconstruction surgery.

Computerized three-dimensional design for accurate orienting and dimensioning artificial dental socket for tooth autotransplantation

OBJECTIVE

To present an improved, accurate, and efficient method for planning and preparing an artificial socket for autotransplantation, by using a three-dimensional (3D) surgical guide and a replica of the transplanted donor tooth. The guide and the tooth replica were fabricated using a computerized 3D simulation. A case treated with this approach is presented.

METHOD AND MATERIALS

Cone beam computed tomography (CBCT) and computerized 3D simulations (Simplant plus registration as stereolithography) were used for planning the optimal artificial socket position and dimensions, within the limitations of the alveolar bone borders and the adjacent teeth roots, and for producing a metal replica of the transplanted tooth. The replica was used to assure the correct socket preparation and orientation before extraction and replantation of the donor premolar.

RESULTS

The entire procedure time for autotransplantation of a permanent second premolar to the incisor site without the buccal plate was about 45 minutes. At 15 months' follow up, clinical examination of the transplanted tooth demonstrated both normal mobility and no sensitivity to cold stimulation. A radiographic examination revealed continuous root development and pulp obliteration. The adjacent teeth maintained their vitality with no pathologic signs.

CONCLUSION

We present an improved technique for autotransplantation based on computerized 3D simulations and guidance for accurate dimensioning and optimal locating of the artificial socket relative to the alveolar bone borders and the adjacent teeth roots. This technique may significantly simplify the autotransplantation procedure and will probably also increase its success rate and use in young patients, even in cases with absence of a buccal plate.

Digital implantological workflow for a CAD/CAM immediate long-term temporary restoration for the edentulous maxilla

The rehabilitation of the edentulous jaw using angulated implants and screw-retained retrievable fixed prosthetic dentures is a well-established treatment method. Possible advantages include the option to avoid bone augmentation, to provide an immediate long-term provisional restoration, and, where appropriate, to perform a minimally invasive procedure. A variety of prosthodontic solutions are available for the definitive restoration, not least allowing the patient's financial situation to be accommodated. Implementing this concept requires systematic planning and an exacting surgical procedure. It makes sense to rely on a computer-assisted process for this purpose as it standardizes the procedure and makes it reproducible, with all the benefits this entails. The present report highlights the consistent integration of virtual planning and computer-aided design/computer-aided manufacturing (CAD/CAM), from the surgical template to the immediate long-term provisional restoration. The relevant procedures are described in general terms and illustrated by a patient case.

Computer-designed surgical guide template compared with free-hand operation for mesiodens extraction in premaxilla using "trapdoor" method

The aim of this study was to introduce a novel method of mesiodens extraction using a vascularized pedicled bone flap by piezosurgery and to compare the differences between a computer-aided design surgical guide template and free-hand operation.A total of 8 patients with mesiodens, 4 with a surgical guide (group I), and 4 without it (group II) were included in the study. The surgical design was to construct a trapdoor pedicle on the superior mucoperiosteal attachment with application of piezosurgery. The bone lid was repositioned after mesiodens extraction. Group I patients underwent surgeries based on the preoperative planning with surgical guide templates, while group II patients underwent free-hand operation. The outcome variables were success rate, intraoperative time, anterior nasal spine (ANS) position, changes of nasolabial angle (NLA), and major complications. Data from the 2 groups were compared by SPSS 17.0, using Wilcoxon test.The operative time was significantly shorter in group I patients. All the mesiodentes were extracted successfully and no obvious differences of preoperative and postoperative ANS position and NLA value were found in both groups. The patients were all recovered uneventfully.Surgical guide templates can enhance clinical accuracy and reduce operative time by facilitating accurate osteotomies.

A new design of CAD/CAM surgical template system for two-piece narrowing genioplasty

The purpose of this study was to develop and validate a new chin template system for a two-piece narrowing genioplasty. Nine patients with wide chin deformities were enrolled. Surgeries were planned with the computer-aided surgical simulation (CASS) planning method. Surgical splints and chin templates were designed in a computer and fabricated using a three-dimensional printing technique. The chin template system included a cutting guide and a repositioning guide for a two-piece narrowing genioplasty. These guides were also designed to avoid the mental foramen area and inferior alveolar nerve loops during the osteotomy, for nerve protection. After surgery, the outcome evaluation was completed by first superimposing the postoperative computed tomography model onto the planned model, and then measuring the differences between the planned and actual outcomes. All surgeries were completed successfully using the chin template system. No inferior alveolar nerve damage was seen in this study. With the use of the chin templates, the largest linear root mean square deviation (RMSD) between the planned and the postoperative chin segments was 0.7mm and the largest angular RMSD was 4.5°. The results showed that the chin template system provides a reliable method of transfer for two-piece osseous narrowing genioplasty planning.

Minimally invasive corticotomy in orthodontics: a new technique using a CAD/CAM surgical template

Accelerating orthodontic tooth movement is a topical issue. Despite the different techniques described in the literature, the corticotomy is the only effective and safe means of accelerating orthodontic tooth movement. Although effective, the corticotomy presents significant postoperative discomfort. The aggressive nature of these particular methods, related to the elevation of mucoperiosteal flaps and to the length of the surgery, has resulted in reluctance to proceed with this technique among both patients and the dental community. To overcome the disadvantages of the corticotomy, this technical note describes an innovative, minimally invasive, flapless procedure combining piezoelectric surgical cortical micro-incisions with the use of a 3D Printed CAD/CAM surgical guide.

A randomized clinical trial comparing guided implant surgery (bone- or mucosa-supported) with mental navigation or the use of a pilot-drill template

AIM

To assess the accuracy of guided surgery (mucosa and bone-supported) compared to mental navigation or the use of a surgical template, in fully edentulous jaws, in a randomized controlled study.

MATERIAL AND METHODS

Fifty-nine patients (72 jaws), requiring four to six implants (maxilla or mandible), were consecutively recruited and randomly assigned to one of the following treatment groups; guidance via Materialise Universal(®)/mucosa, Materialise Universal(®)/bone, Facilitate™/mucosa, Facilitate™/bone, or mental navigation or a pilot-drill template. The precision was assessed by matching the planning computed tomography (CT) with a post-operative cone beam CT.

RESULTS

A significant lower mean deviation at the entry point (1.4 mm, range: 0.3-3.7), at the apex (1.6 mm, range: 0.2-3.7) and angular deviation (3.0°, range: 0.2-16°) was observed for the guiding systems when compared to mental navigation (2.7 mm, range: 0.3-8.3; 2.9 mm, range: 0.5-7.4 and 9.9°, range: 1.5-27.8) and to the surgical template group (3.0 mm, range: 0.6-6.6; 3.4 mm, range: 0.3-7.5 and 8.4°, range: 0.6-21.3°). Differences between bone and mucosa support or type of guidance were negligible. Jaw and implant location (posterior-anterior, left-right), however, had a significant influence on the accuracy when guided.

CONCLUSION

Based on these findings, guided implant placement appears to offer clear accuracy benefits.

A novel dental implant guided surgery based on integration of surgical template and augmented reality

BACKGROUND

Stereoscopic visualization concept combined with head-mounted displays may increase the accuracy of computer-aided implant surgery.

PURPOSE

The aim of this study was to develop an augmented reality-based dental implant placement system and evaluate the accuracy of the virtually planned versus the actual prepared implant site created in vitro.

MATERIALS AND METHODS

Four fully edentulous mandibular and four partially edentulous maxillary duplicated casts were used. Six implants were planned in the mandibular and four in the maxillary casts. A total of 40 osteotomy sites were prepared in the casts using stereolithographic template integrated with augmented reality-based surgical simulation. During the surgery, the dentist could be guided accurately through a head-mounted display by superimposing the virtual auxiliary line and the drill stop. The deviation between planned and prepared positions of the implants was measured via postoperative computer tomography generated scan images.

RESULTS

Mean and standard deviation of the discrepancy between planned and prepared sites at the entry point, apex, angle, depth, and lateral locations were 0.50 ± 0.33 mm, 0.96 ± 0.36 mm, 2.70 ± 1.55°, 0.33 ± 0.27 mm, and 0.86 ± 0.34 mm, respectively, for the fully edentulous mandible, and 0.46 ± 0.20 mm, 1.23 ± 0.42 mm, 3.33 ± 1.42°, 0.48 ± 0.37 mm, and 1.1 ± 0.39 mm, respectively, for the partially edentulous maxilla. There was a statistically significant difference in the apical deviation between maxilla and mandible in this surgical simulation (p < .05).

CONCLUSIONS

Deviation of implant placement from planned position was significantly reduced by integrating surgical template and augmented reality technology.

An optimal design for patient-specific templates for pedicle spine screws placement

BACKGROUND

Currently, pedicle screws are positioned using a free-hand technique or under fluoroscopic guidance, with error in the range 10-40%, depending on the skill of the surgeon.

METHODS

After spine CT acquisition, each vertebra is segmented and the surgeon plans screw positioning in a virtual environment, then the template is designed around the chosen trajectories. This design is based on surgical and mechanical considerations to obtain an optimal solution to guarantee template stability, simple positioning and minimized intervention invasiveness. In vitro evaluation on synthetic spine models and ex vivo animal tests on porcine specimens were performed, with the insertion of 28 Kirschner wires.

RESULTS

During the in vitro tests, all the surgeons rendered positive evaluations regarding the device and considered template placement to be easy. Ex vivo tests were evaluated by CT examination, which showed that 96.5% of the Kirschner wires had been correctly inserted.

CONCLUSIONS

The proposed solution is a promising, simple, highly precise, low-cost solution to safely performing posterior stabilization. Such a solution would be of interest even in hospitals in which a few spine interventions are performed per year, and for which it is not reasonable to purchase the equipment required for robotic or navigated approaches.