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Chernohorskyi D. M., Chepurnyi Y. V., Vasiliev O. S., Voller M. V., Kopchak A. V. Evaluation of the accuracy of surgical reconstruction of mandibular defects when using navigation templates and patient-specific titanium implants. Journal of Education, Health and Sport. 2021;11(2):117-132. eISSN 2391-8306. DOI http://dx.doi.org/10.12775/JEHS.2021.11.02.013 https://apcz.umk.pl/czasopisma/index.php/JEHS/article/view/JEHS.2021.11.02.013 https://zenodo.org/record/4594307 The journal has had 5 points in Ministry of Science and Higher Education parametric evaluation. § 8. 2) and § 12. 1. 2) 22.02.2019. © The Authors 2021; This article is published with open access at Licensee Open Journal Systems of Nicolaus Copernicus University in Torun, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike. (http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 11.01.2021. Revised: 10.02.2021. Accepted: 26.02.2021. Evaluation of the accuracy of surgical reconstruction of mandibular defects when using navigation templates and patient-specific titanium implants D. M. Chernohorskyi, Y. V. Chepurnyi, O. S. Vasiliev, M. V. Voller, A. V. Kopchak O.O. Bogomolets National Medical University, Kyiv, Ukraine Stomatology department Abstract The management of patients with post-traumatic and post-operative mandibular defects is a major challenge even for experienced surgeons. Performing traditional reconstructive interventions with the use of bone autografts is always confronted with the problem of inconsistency between the shape, architecture, a biological. An alternative to conventional bone grafting is the use of digital protocol and CAD / CAM technology, which allows fabricating different types of customised medical devices. All patients underwent reconstructive and restoring interventions with the use of patient-specific titanium implants guided by a full digital protocol. Patients were examined in compliance with the standard scheme. To repair the defects, PSIs were fabricated with the use of selective laser sintering of titanium. The introduction of digital technologies and computer technique of diagnosing, planning and implementation of surgical interventions has been the main direction aimed at the improving the accuracy and predictability of reconstructive restorative surgery. Among the main achievements in this direction are the improvement of software and methods of computer modeling, as well as the introduction of CAD / CAM technology. The use of CAD / CAM technologies, in particular, navigational surgical templates and patient-specific implants for the repair of mandibular defects ensures a high level of accuracy and predictability. Key words: Patient-specific implant; mandibular defect; mandible segmentation; mandible reconstruction; navigation templates.

Background Fibula free flap mandible reconstruction is the standard procedure after wide resection of the mandible. Establishment and maintenance of normal occlusion are important in mandible reconstruction both intraoperatively and after surgery. However, scar formation on the surgical site can cause severe fibrosis and atrophy of soft tissue in the head and neck region. Case presentation Here, we report a case of severe soft tissue atrophy that appeared along with scar formation after mandibular reconstruction through the fibular free flap procedure. This led to normal occlusion collapse after it was established, and the midline of the mandible became severely deviated to the affected side that was replaced with the fibula free flap, leading to facial asymmetry. We corrected the malocclusion with a secondary operation: a sagittal split ramus osteotomy on the unaffected side and a sliding osteotomy on the previous fibula graft. After a healing time of 3 months, implants were placed on the fibula graft for additional occlusal stability. Conclusion We report satisfactory results from the correction of malocclusion after fibula reconstruction using sliding fibula osteotomy and sagittal split ramus osteotomy. The midline of the mandible returned to its original position and the degree of facial asymmetry was reduced. The implants reduced difficulties that the patient experienced with masticatory function.

Background The reconstruction of segmental mandibular defects remains a challenge for the reconstructive surgeon, from both a functional and an esthetic point of view. Methods This clinical review examines the different techniques currently in use for mandibular reconstruction as related to a range of etiologies, including the different bone donor sites, the alternatives to free flaps (FFs), as well as the contribution of computer‐assisted surgery. Recent progress and the perspectives in bone tissue engineering (BTE) are also discussed. Results Osseous FF allows reliable and satisfying outcomes. However, locoregional flap, distraction osteogenesis, or even induced membrane techniques are other potential options in less favorable cases. Obtaining an engineered bone with satisfactory mechanical properties and sufficient vascular supply requires further investigations. Conclusions Osseous FF procedure remains the gold standard for segmental mandible reconstruction. BTE strategies offer promising alternatives.

Background: The customized prosthesis is a new method for the reconstruction of large mandibular defects. The ability of dental rehabilitation to improve masticatory functions while maintaining the aesthetics of the main anatomy of the patient’s jaw. But the most important problem with all custom prosthesis is the poor performance of screw fixation strength the connections at the bone-plate interface. Materials and Methods: This study was performed to investigate the effect of the number and layout of screws to improve the strength of the bone–prosthesis interface. Due to the inherent variability of input parameters, Analysis of the biomechanical performance of screw fixation strength, a probabilistic finite element method approach has been used. Random input parameters include mechanical properties of the cortical bone, cancellous bone, titanium alloy (Ti6Al4V), and bite force. The layout of the screws was designed in 6 models. Criteria for evaluating the biomechanical performance of screw fixation strength include maximum stress and strain of von Mises cortical bone around the screws. The Monte-Carlo method was used for finite element simulation. Results: The most critical screw in all models is screw No.1, which by increasing the number of screws and correcting the layout shape, the values of maximum stress and strain in the bone around screw No.1 has decreased by 26.7% and 46.3%, respectively, and increased the reliability of the screw connection performance by 25% and 28%, respectively. Conclusion: Finally, in the reconstruction of a large lateral mandibular defect by the customized prosthesis, the strength of the prosthesis to connect to the remaining mandible bone can be improved by increasing the number and modifying the layout of the screws. Keywords: Mandible reconstruction; Customized prosthesis; Probabilistic finite element method; Reliability.

This paper proposes a semi-autonomous robot control system for mandible reconstruction surgery. To reconstruct a segmental defect of the mandible caused by cancerous tissue, a piece of matched fibula bone is often segmented and used to replace the removed mandible section. In this paper, to provide guidance to the surgeon during fibula segmentation according to the reconstruction surgical plan and to improve the fibula bone cutting accuracy, an admittance-controlled robotic assistant incorporating 3D augmented reality (AR) visualization and haptic virtual fixtures (VF) is proposed. The admittance controller is used to reduce the surgeon’s hand tremor. The VF and AR are used to provide haptic and visual guidance to the surgeon, respectively. A feasibility study is performed through a comparison of fibula osteotomies when performed with image-guided surgery, AR-guided surgery, VF-guided robot-assisted surgery, and AR-and VF-guided robot-assisted surgery. Experimental results show the effectiveness of the proposed admittance-controlled robotic assistant with AR and VF compared to the other three methods. The proposed method was found to beable to increase precision of the osteotomized segments with a lower average linear variation of 1.04 ±0.79 mm and a lower average angular variation of 1.83 ±1.85° compared to the virtual preoperative plan.

Background This clinical case presented a novel method of segmental mandible reconstruction using 3D-printed titanium implant with pre-mounted dental implants that was planned to rehabilitate occlusion. Case presentation A 53-year-old male who suffered osteoradionecrosis due to the radiation after squamous cell carcinoma resection. The 3D-printed titanium implant with pre-mounted dental implant fixtures was simulated and fabricated with selective laser melting method. The implant was successfully inserted, and the discontinuous mandible defect was rehabilitated without postoperative infection or foreign body reaction during follow-ups, until a year. Conclusions The 3D-printed titanium implant would be the one of the suitable treatment modalities for mandible reconstruction considering all the aspect of mandibular functions.

In the present study, the reproducibility and postoperative stability of a 3D printed surgical guide were evaluated in mandibular reconstruction with an osteocutaneous free flap (OCFF), including a fibular free flap (FFF) and deep circumflex iliac artery free flap (DCIA). Fifteen patients were enrolled, and a 3D surgical guide was fabricated by simulation surgery using preoperative (T0) Computed tomography (CT) images. Mandibular reconstruction was performed with OCFF using the 3D surgical guide. Postoperative CTs were taken immediately, 1 week (T1), and 6 months (T2) after surgery, to evaluate the reproducibility of the 3D surgical guide and condyle stability. Error of the 3D surgical guide ranged from 0.85 to 2.56 mm. There were no differences in reproducibility according to flap type. Condylar error and error at mandible midpoint were significantly different in FFF. However, there was no difference in DCIA error between the condyle and mandible midpoint. Regarding condyle stability 6 months after surgery, condyles moved more than 2 mm (up to 2.85 mm) in FFF, whereas there were no significant movement in DCIA. Careful intraoperative flap fixation and closed postoperative observation should be considered for stable clinical outcome, especially in the case of FFF.

Severe restriction of airway volume in the orofacial region, caused by temporomandibular joint (TMJ) ankylosis, may lead to obstructive sleep apnea (OSA). If the TMJ ankylosis is progressive, rarely, the caregivers may fail to notice the problem. Such patients may have only symptoms of snoring, daytime sleepiness, fatigue, inability to concentrate, and irritability. At times, emergency tracheostomy may be needed to increase the oxygen supply. Distraction osteogenesis (DO) is a less invasive surgical technique in the management of such OSA by correcting the reduced airway space. In DO, the angulation of the distractors and the pace of activation determine the success of the neo-generation of segments of bone. The formation of a well-corticated mandibular canal (MC) in the newly generated bone is an evidence of the success of the procedure. Such bilateral formation of the MC is not reported from this part of the world. We report a case of a 4-year-old boy who was struggling with OSA due to TMJ ankylosis. He was successfully treated by bilateral mandibular DO. The formation and cortication of the MC is discussed with emphasis on the neural regeneration.

Rosai–Dorfman disease or sinus histiocytosis is a rare entity which may affect various lymph node groups. Extranodal form is observed in 45 % of cases, facial bone involvement is especially rare. A 62-year old male presented with complaints on dumb sensation of the chin and lower lip. After clinical assessment and surgical exploration an intraosseous extranodal Rosai–Dorfman disease was diagnosed. The patient under-went free fibula osseous graft reconstruction. After 2 years the patient is recurrent free. The purpose of this publication is to describe a rare case of lower jaw involvement in an intraosseous form with significant bone destruction. The clinical and microscopic features of the process are discussed.

The iliac crestal flap is often used in maxillofacial reconstruction surgery because it has a similar bone contour to jaw bone. However, complications occur frequently in this flap, and the avulsion fracture of the anterior superior iliac spine (ASIS) occurs only in rare cases. The purpose of this study is to evaluate the risk factors affecting fractures that may occur after iliac crestal flap harvesting. In this study, we performed preoperative and postoperative CT scans of the iliac bones of 22 patients who underwent iliac crestal flaps between February 2013 and July 2019. Three of these patients had fractures within 1 month after surgery. After converting DICOM files to a three-dimensional model using Mimics software, some reference points were defined for analysis. The patients were classified into fracture and non-fracture groups. The patients’ age and sex, harvested bone, residual bone and absolute bed rest (ABR) periods were investigated. The patients’ age and sex were not associated with fracture occurrence. There was a statistically significant difference in the width of the anterior–superior part of residual bone. The fracture group showed statistically significantly shorter ABR periods. In the case of the iliac crestal flap, it was found that the factors that can affect the occurrence of fractures are the width of the residual bone and the ABR period. Iliac avulsion fracture can be prevented when the remaining bone is sufficient and the ABR period is prolonged sufficiently.

Ameloblastoma is a benign dental tumor mostly found in the mandible, with several variations. The treatment of this pathology ranges from simple enucleation to resection of large sections of the affected bone. There are several options for correcting the sequelae of ameloblastoma treatment, including the use of grafts and currently microvascular free flaps, which have become the standard treatment. This report describes a clinical case of a large mandibular ameloblastoma, which was resected with safety margins about 10 years ago, reconstructed by free grafts in successive surgical times and rehabilitated using removable prostheses. The question is then what the best option is today in the reconstruction of patients affected by this type of pathologies, taking into account emerging options, the clinicians’ learning curve and the patients’ resources.

Aims: The aim of the study is to audit the titanium reconstruction of jaw defects in benign conditions in Christian Medical College and Hospital , Vellore. Methods and Material: A retrospective study of titanium reconstruction of mandibular defects due to jaw lesions at Christian Medical College and Hospital, Vellore, India, between May 2008 and May 2011. Results: Mouth opening, facial symmetry, occlusion, chewing ability, plate exposure and patient satisfaction were used as outcome measures. Conclusions: The three-dimensional titanium plate is a reasonable material for immediate mandible reconstruction after surgical resection of benign jaw pathologies.

We did biomechanical loading tests to compare the quantity and quality of interfragmentary movement in fractured human cadaver mandibles that had been reconstructed with iliac crest using 3 different osteosynthesis systems. Eighteen mandibles from human cadavers with a 4.5 cm paramedian L-type defect were reconstructed with bone from the iliac crest using 3 different osteosynthesis systems and continuously loaded on the "Mandibulator" test bench. Six mandibles each had the bones joined together using 2 monocortical non-locking plates, 2 monocortical locking plates, or a single bicortical locking plate/fracture gap. Macroscopic deformation, failure mechanisms, and movement of the fracture gap in all 3 dimensions were assessed and quantified over increasing loading by PONTOS(?) optical measurement systems. Final mechanisms of failure were excessive deformation of the plate, fracture of the mandibular fragments, and failure of the iliac crest graft. The plate became deformed mainly in the miniplate group. The iliac crest graft failed in all the specimens in which osteosynthesis was performed by a 6-hole TriLock(?) plate. Interfragmentary movement was minimised in the miniplate group. All three osteosynthesis systems provided sufficient stability for reconstruction when mechanically loaded up to 100 N. The miniplate allowed less movement in the gap and gave better stability than the two TriLock(?) plate systems. The superiority of the miniplate was significant when compared with the 4-hole TriLock(?) plate. The transplant failed mainly in the 6-hole TriLock(?) group, which suggests that the iliac crest graft works better with the miniplate as a more malleable osteosynthesis system. The British Association of Oral and Maxillofacial Surgeons.

This paper describes a new protocol for mandibular reconstruction. Computer-aided design/computer-aided manufacturing (CAD/CAM) technology was used to manufacture custom-made cutting guides for tumor ablation and reconstructive plates to support fibula free flaps. CT scan data from a patient with an odontogenic keratocyst on the left mandibular ramus were elaborated to produce a virtual surgical plan of mandibular osteotomy in safe tissue for complete ramus resection. The CAD/CAM procedure was used to construct a customized surgical device composed of a cutting guide and a titanium reconstructive bone plate. The cutting guide allowed the surgeon to precisely transfer the virtual planned osteotomy into the surgical environment. The bone plate, including a custom-made anatomical condylar prosthesis, was designed using the outer surface of the healthy side of the mandible to obtain an ideal contour and avoid the bone deformities present on the side affected by the tumor. Operation time was reduced in the demolition and reconstruction phases. Functional and aesthetic outcomes allowed patients to immediately recover their usual appearance and functionality. This new protocol for mandibular reconstruction using CAD/CAM to construct custom-made guides and plates may represent a viable way to reproduce the patient’s anatomical contour, give the surgeon better procedural control, and reduce operation time.

AIM: The objective of this study was to evaluate the incidence of plate-related complications after vascularized bony reconstruction of the mandible, comparing the plate type used. PATIENTS AND METHODS: Between 2004 and December 2012, a total of 41 free osteocutaneous fibula flaps have been used in an equal number of patients for reconstruction of the mandible, at the Division of Maxillofacial surgery, San Giovanni Battista Hospital, University of Turin. Malignant pathology was the most common indication for segmental mandibulectomy.Patient outcomes were retrospectively evaluated with special attention to plate complications such as plate fracture, exposure, infection, and bony nonunion.The types of reconstruction plates used were mandible plates 2.0, locking plates 2.0, miniplates (

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:24:39Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:41:18Z : No. of bitstreams: 1 2-s2.0-77955529726.pdf: 270693 bytes, checksum: f67dd0a707d7b45e3c82a424f5bba8c3 (MD5) Made available in DSpace on 2014-05-27T11:24:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-01 The treatment of Class II adult individuals with mandibular deficiency has been the combination of orthodontic treatment and orthognathic surgery. Therefore, a study was conducted in which cephalometric analysis was used to evaluate the influence of dentoalveolar decompensation in Class II patients submitted to orthodontic and surgical treatment for mandibular advancement, by bilateral osteotomy of the mandibular ramus. A sample of 15 leukoderma adult female patients were selected and three cephalometric radiographs of each patient, taken before the orthodontic treatment, before surgery and after at least 6 months postoperatively, were analyzed in a total of 45 roentgenograms. The tracings were made by the manual method and the points were digitalized using software. The results showed that values of SNB increased from 75.6 to 78.6°. The measures BNP and PGNP were reduced from -12.7 to -7.7 mm and -12.7 to -6.6 mm, respectively. For ANB there was a reduction of 3.23° (from 8.1° to 4.9°). Likewise, the values of AOBO were diminished by 6.3 mm (from 7.6 to 1.3 mm), and in the values of OJ there was a reduction of 5.7 mm (from 9 to 3.3 mm). It was concluded that the pre-surgical orthodontic treatment promoted minimal and variable dental and skeletal changes in the final result. The surgical treatment caused significant skeletal changes, especially in the measurements related to the mandible (SNB, BNP, PGNP and SNPM) or indirectly to it (ANB, AOBO and OJ). Department of Orthodontics Herminio Ometto University Center Araras University (UNIARARAS), Araras, SP Department of Orthodontics Faculdade de Odontologia de Araraquara Universidade Estadual Paulista (UNESP), Araraquara, SP Department of Surgery Piracicaba Dental School University of Campinas (UNICAMP), Piracicaba, SP Department of Orthodontics Faculdade de Odontologia de Araraquara Universidade Estadual Paulista (UNESP), Araraquara, SP

The aim of mandible reconstruction using reconstruction plate after resection is to restore aesthetic and function for muscles attachment and allow mandible movement during normal function and free from joint problem. Temporomandibular joint (TMJ) is an area of concern during mandible reconstruction using reconstruction plate as misalignment on placing of the reconstruction plate may cause the joint place in distortion to the glenoid fossa. Loss large part of mandible bone structure may lead problems during mandible reconstruction procedure because the surgeon may lose in orientation during forming the reconstruction plate into a horseshoe-shaped form of the mandible as well as during plate placement. The plate can only be well adapted when the position of two distal ends of the resected mandible bone are in a stable position. Simple ascending ramus fixator (CARF) to fix the ascending ramus in its stable original position to allow easy mandible reconstruction was created. Those CARF were designed in two types which have one and two fixator stems used to stabilize one or both sites of the ascending rami and showed its effectiveness.

Traumas, malformative or dysplastic pathologies, atrophy, osteoradionecrosis, and benign or malignant neoplasm can cause bone deficits in the mandible. Consequent mandibular defects can determine aesthetic and functional problems; therefore, being able to perform a good reconstruction is of critical importance.Several techniques have been proposed for mandibular reconstruction over the years. In this article, we present and discuss the evolution during the time of the methods of mandible reconstruction as well as pros and cons of each procedure on the basis of experience of 10 years in the maxillofacial department of the Catholic University of Sacred Heart of Rome.Free flaps represent the gold standard method of reconstruction of large mandibular defects: the fibula bone flap represents the best choice for large defects involving the arch and the mandibular ramus, whereas the deep circumflex iliac artery represents a valid alternative for mandibular defects involving the posterior region.In cases where free flap reconstructions are contraindicated, the use of regional pedicle flap combined with autologous bone grafts still represents a valid choice. Patients who are not deemed suitable for long and demanding surgery can still be treated using alloplastic materials in association with regional pedicle flap or, when adjuvant radiation therapy is needed, by simple locoregional pedicle flap. Finally, in selected cases, the bone transporting technique should be considered as a valid alternative to the more "traditional" reconstructive methods because of the extraordinary potential and its favorable cost-benefit ratio.

The aim of this retrospective study was to investigate cephalometrically the skeletal, dental, and soft tissue modifications induced by activator treatment in patients with Class II malocclusions caused by mandibular retrognathism. The subjects, all in the mixed dentition, were selected from a single centre and were divided into two groups: 40 patients treated with an incisor double capping activator (20 girls, 20 boys with a mean age of 10 years) and a control group of 30 subjects (15 girls, 15 boys with a mean age of 10 years). The dentoskeletal and aesthetic changes that occurred were compared on lateral cephalograms taken before treatment (T0) and after 18-24 months, when the activator was removed (T1). In the control group the radiographs were obtained before (T0) and after (T1) 21 months (standard deviation +/- 3 months). Activator treatment in these growing patients resulted in a correction of the Class II relationship (ANB -2.14 degrees), a restriction of maxillary growth (SNA -0.5 degrees), an advancement of the mandibular structures (SNB +1.64 degrees, FH--NPg +3.39 degrees; OLp-B +5.17 mm, OLp-Pg +5.14 mm, OLp-Go +2.44 mm), a correction of the overjet (-5.03 mm), an improvement in overbite (-1.17 mm) and uprighting of the maxillary incisors (1--FH -5.64 degrees). The activator appliance was effective in treating growing patients with mandibular deficiency: activator therapy corrected Class II malocclusions by a combination of skeletal and dental changes and improved the soft tissue facial profile.

This report describes a novel protocol for the construction of surgical cutting guides and reconstructive titanium bone plates to guide osteotomies according to the preoperative plan and to position and fix an osseous free flap in mandibular reconstruction after cancer removal. Computed tomographic data of a mandible affected by an ameloblastoma were elaborated to produce a virtual surgical plan that included the osteotomy cuts, area of bone resection, and reconstruction. STLfiles were elaborated for use with direct metal laser sintering, and a cutting guide and custom-made bone fixation plate were rapidly prototyped. The operating time was reduced in both the demolition and reconstruction phases. The patient's usual appearance and functionality were restored immediately. The new protocol for mandibular reconstruction is a viable way of reproducing the patient's anatomical contour while giving the surgeon better procedural control and reducing operating time. The innovative technique presented here involves three steps: (1) surgery planning, (2) computer-aided design/computer-aided manufacture and rapid prototyping, and (3) the surgery. High-resolution computed tomographic images of the patient's craniofacial skeleton and soft tissues were acquired using a multidetector computed tomography scanner (HiSpeed CT scanning station; General Electric Company, Fairfield, Conn.). The Digital Imaging and Communications in Medicine–format data were processed by the surgeons using CMF 6.0 software (Materialise, Leuven, Belgium). Three projections of the bone cuts were made in the three spatial axes and imported in Rhino 4.0 software (Robert McNeel & Associates, Seattle, Wash.) to allow the perfect transfer of the surgical plan. The computer-aided design of the surgical device was obtained using Rhino 4.0 software. The first component was a customized cutting guide for use in mandibular resection and to maintain free space after tumor ablation (Fig. 1, above). The second component was a customized reconstructive bone plate to support the iliac free flap (Fig. 1, below). The plate was designed by thickening the outer surface of the mirrored healthy side of the mandible to obtain an ideal mandibular contour and to avoid bone deformities on the side affected by the tumor. Reference notches were also added to delimit the part that would support the free flap. The two components (cutting guide and bone plate) were projected so that the same holes for the screws to fix the guide were used to secure the bone plate that supported the free flap. The cutting guide and bone plate were manufactured directly using the EOSINT M270 system (Electro Optical Systems, Munich, Germany). EOS CobaltChrome MP1 (Electro Optical Systems) was used to produce the cutting guide. The bone plate was produced with EOS Titanium Ti64 (Electro Optical Systems). A man with an ameloblastoma of the left mandibular body underwent mandibular resection and reconstruction using an iliac free flap. The mandibular cutting guide was fixed to the mandible to reproduce the demolition plan (Fig. 2, above). After mandibular resection, the cutting guide was removed and the reconstructive plate was introduced and fixed using the same holes as for the cutting guide. The reconstructive bone plate supported the iliac free flap in the correct position to restore the patient's original mandibulofacial contour exactly (Fig. 2, below). The protocol presented here offers several benefits. First, the virtual environment permitted optimal preoperative planning for tumor ablation: the resection boundaries were chosen accurately in safe tissues. No operating time was consumed by modeling a plate to the native mandible.1–5 Second, the morphology of the opposite hemimandible was mirrored and the reconstruction bone plate was designed using the external healthy cortical bone as a template, reproducing the patient's ideal mandibular contour and avoiding potential bone deformities. Co...

In this report, we describe the first successful case of microvascular free tissue transfer in a patient with Evans Syndrome (ES), a rare form of idiopathic thrombocytopenic purpura (ITP) and associated autoimmune hemolytic anemia (AIHA). Microvascular surgery in the setting of ES is likely to have higher complication rates because of the increased risk of postoperative bleeding and free flap thrombosis. The case presented here opens up to the feasibility of microvascular reconstruction of patients with coagulation disorders like ES. Every effort should be made to control for hemolytic, thrombocytopenic, and thrombophilic states associated with ES. In the absence of evidence-based treatment guidelines for ES, personalized treatment protocols with high-dose corticosteroids, immunoglobulin, and postoperative anticoagulation regimen are highly recommended.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:29:00Z No. of bitstreams: 0 Made available in DSpace on 2014-05-27T11:29:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-04-26 A finite element analysis was used to compare the effect of different designs of implant-retained overdentures and fixed full-arch implant-supported prosthesis on stress distribution in edentulous mandible. Four models of an human mandible were constructed. In the OR (O'ring) group, the mandible was restored with an overdenture retained by four unsplinted implants with O'ring attachment; in the BC (bar-clip) -C and BC groups, the mandibles were restored with overdentures retained by four splinted implants with bar-clip anchor associated or not with two distally placed cantilevers, respectively; in the FD (fixed denture) group, the mandible was restored with a fixed full-arch four-implant-supported prosthesis. Models were supported by the masticatory muscles and temporomandibular joints. A 100-N oblique load was applied on the left first molar. Von Mises (σvM), maximum (σmax) and minimum (σmin) principal stresses (in MPa) analyses were obtained. BC-C group exhibited the highest stress values (σvM=398.8, σmax=580.5 and σmin=-455.2) while FD group showed the lowest one (σvM=128.9, σmax=185.9 and σmin=-172.1). Within overdenture groups, the use of unsplinted implants reduced the stress level in the implant/prosthetic components (59.4% for σvM, 66.2% for σmax and 57.7% for σmin versus BC-C group) and supporting tissues (maximum stress reduction of 72% and 79.5% for σmax, and 15.7% and 85.7% for σmin on the cortical and trabecular bones, respectively). Cortical bone exhibited greater stress concentration than the trabecular bone for all groups. The use of fixed implant dentures and removable dentures retained by unsplinted implants to rehabilitate edentulous mandible reduced the stresses in the periimplant bone tissue, mucosa and implant/prosthetic components. © 2013 Elsevier Ltd. Department of Dental Materials and Prosthodontics Araçatuba Dental School Univ Estadual Paulista (UNESP), Sao Paulo Smarttech Company, Sao Paulo Department of Prosthodontics and Periodontology Piracicaba Dental School State Univ of Campinas (UNICAMP), Sao Paulo Department of Dental Materials and Prosthodontics Araçatuba Dental School Univ Estadual Paulista (UNESP), Sao Paulo

International audience; Major atrophies of the mandible corpus are a significant challenge to implant insertion. Depending on the situation, there are a variety of surgical techniques that can be used to rebuild the corpus and to provide an easy way to insert implants. In cases of normal or reduced prosthetic space, grafts are not possible and reconstruction is performed using a nerve lateralization. In cases of increased prosthetic space there is the possibility for reconstruction using distraction or an onlay bone graft.

Mandibular reconstruction is important for providing good functional and cosmetic results after the resection of a mandibulary segment. Reconstruction plates and titanium meshes are usually used to reconstruct the bony defects in mandible. Although their complications are well known there is not a report on the fractures of a titanium mesh after mandible reconstruction in the literature. We reported a case of a broken titanium mesh after mandible reconstruction.

Background This study examined the usefulness of the fibula positioning guide for boosting the accuracy of mandible reconstructions. Methods Thirty mandibular rapid prototype (RP) models were allocated to experimental (N = 15) and control (N = 15) groups. For reference, we prepared a reconstructed mandibular RP model with a three-dimensional printer, based on surgical simulation. In the experimental group, a fibula positioning guide template and fibula cutting guide, based on simulation, were used to reconstruct the mandible with a fibula graft. In the control group, only the fibula cutting guide, with reference to the reconstructed RP mandible model, was used to reconstruct the mandible with a fibula graft. The two mandibular reconstructions were compared to the surgical simulation by registering images with the non-surgical right side of the mandible. On the reconstructed side, 3D measurements were compared between the surgical simulation and actual surgery, and the sum of differences was taken as the total error. Results The combined use of the fibula cutting and positioning guides produced a smaller total error (mean ± SD: 10.0 ± 7.9 mm) than the fibula cutting guide alone (12.8 ± 8.8 mm; p = 0.015). The greatest point error was the vertical error at the mesial point of the anterior fibula segment. The anteroposterior and lateral errors were not significantly different between groups. These results showed that these two methods were not significantly different, except in the total and vertical errors. Conclusions Considering the CAD/CAM processes required for creating positioning devices, the benefit provided with a positioning guide justified its use over the fibula cutting guide alone.

Background This study aimed to evaluate the accuracy of surgical outcomes in free iliac crest mandibular reconstructions that were carried out with virtual surgical plans and rapid prototyping templates. Methods This study evaluated eight patients who underwent mandibular osteotomy and reconstruction with free iliac crest grafts using virtual surgical planning and designed guiding templates. Operations were performed using the prefabricated guiding templates. Postoperative three-dimensional computer models were overlaid and compared with the preoperatively designed models in the same coordinate system. Results Compared to the virtual osteotomy, the mean error of distance of the actual mandibular osteotomy was 2.06 ± 0.86 mm. When compared to the virtual harvested grafts, the mean error volume of the actual harvested grafts was 1412.22 ± 439.24 mm3 (9.12% ± 2.84%). The mean error between the volume of the actual harvested grafts and the shaped grafts was 2094.35 ± 929.12 mm3 (12.40% ± 5.50%). Conclusions The use of computer-aided rapid prototyping templates for virtual surgical planning appears to positively influence the accuracy of mandibular reconstruction.