Patient-specific implants for maxillofacial defects: challenges and solutions

A method for accuracy of placement analysis on radiolucent polyether-ether-keton facial implants: A case series

Facial asymmetry is defined as a bilateral difference between facial components. Correction, often desired by the patient, can be performed with the aim of bone born patient-specific solid implants designed using 3D CAD software. This treatment is embedded in the daily practice of today's healthcare. However, an analysis of the implant's accuracy of placement has not been reported. This case series describes the accuracy analysis of bone born aesthetic facial implants manufactured out of polyether-ether-ketone (PEEK). The accuracy analysis was based on postoperative (cone beam) computed tomography ((CB)CT) data and preoperative 3D planning. The analysis showed a median entry point error of 0.7 mm (min: 0.1, max: 3.3, interquartile range: 0.78). The median maximal orientation error was 5.5° (min: 0.1, max: 36.8, interquartile range: 7.13). Both parameters showed an excellent intraobserver and interobserver agreement with an ICC above 0.84. The described cases show that the analysis method is an objective approach for determining the accuracy of PSI placement and indicates that these implants can be placed accurately on the osseous face.

Validation of Low Cost Patient Specific Implant Design Using Finite Element Analysis (FEA) for Reconstruction of Segmental Mandibular Defects: A Case Report and Literature Review

Introduction

Mandibular continuity defects can cause functional and cosmetic deformities affecting a patient's quality of life. Reconstruction of such defects can be intricate even for the most seasoned maxillofacial surgeons. Reconstruction plates were the standard of care in the past, followed by a secondary reconstruction using autogenous grafts.

Materials and methods

Novel technological upgrades like customized computer-designed patient-specific implants (PSIs) have overtaken these stock reconstruction plates to enhance the aesthetics and address the individual clinical situation. Affirmation of the above plate design using biomechanical analysis can further improve the efficacy of PSIs.

Discussion

The present case report describes a novel combination of an autogenous graft and a low-cost patient-specific implant with the prosthesis design validated using finite element analysis. The authors have also reviewed the biomechanical evaluation of PSIs design and its uses in treating mandibular continuity defects.

Conclusion

Use of FEA helped to inspect the potential weakness and stress distribution through out the implant due to this there was no sign of hardware failure.

Influence of porous titanium-based jaw implant structure on osseointegration mechanisms

The reconstruction of maxillofacial defects caused by anomalies, fractures, or cancer is challenging for dentofacial surgeons. To produce efficient, patient-specific implants with long-term performance and biological suitability, numerous methods of manufacturing are utilized. Because additive manufacturing makes it possible to fabricate complex pore structure samples, it is now recognized as an acceptable option to design customized implants. It is well recognized that a porous structure with proper design promotes accelerated cell proliferation, which enhances bone remodeling. Porosity can also be employed to modify the mechanical characteristics of fabricated implants. Thus, design and choice of rational lattice structure is an important task. The influence of the structure of jaw implants made of highly porous titanium-based materials on their mechanical properties and bone tissue growth was studied. Based on a 3D computer model of Wigner-Seitz lattice structure, the model samples were fabricated from Ti6Al4V powder by selective laser melting to characterize the mechanical properties of the samples depending on their macroporosity. Then two types of jaw bone implants were manufactured to conduct studies of bone tissue ingrowth when implanted in laboratory animals. The research was carried out in several stages: design and production of the implants for replacing incomplete defects of the lower jaw; implantation of SLM-printed implants in laboratory animals into an artificially produced defect of the lower jaw; analysis of the degree of fixation of the "implant - bone" connection (for implantation periods from 2 weeks to 9 months). During the research, Ti-alloy structures with cell diameters of 2-3 mm and macroporosity of 90-97% mimicking the spongy structure of trabecular bone tissue, were characterized by a compressive strength of 12.47-37.5 MPa and an elastic modulus of 0.19-1.23 GPa, corresponding to the mechanical properties of bone tissue. Active processes of tissue growth into implant cells were detected 2 weeks after implantation, the significant differences in the volume and types of filling tissue depending on the size of the cell were described. Recommendations for choosing the cell size depending on the type of bone tissue damage were given. When using SLM-printed implants with lattice structure (cell sizes from 1 to 3 mm), an active osteosynthesis processes occurred, which culminated in the formation of bone tissue inside the implant cells 9 months after implantation, with 68% of the samples characterized by the maximum degree of implant fixation. Implants with 3 mm cells with macropores diameters of 850 μm were recommended for replacing cavities after removal of perihilar cysts. To replace complete and partial defects, it was recommended to use implants with a cell size of 2 and 3 mm.

Cranio-Maxillo-Facial Reconstruction with Polyetheretherketone Patient-Specific Implants: Aesthetic and Functional Outcomes

BACKGROUND

Reconstructing cranio-maxillo-facial defects presents significant challenges. This study evaluates the results of polyetheretherketone patient-specific implants (PEEK PSIs) in primary and secondary cranio-maxillo-facial reconstructions, with a focus on aesthetic and functional outcomes and long-term complications.

METHODS

From October 2009 to February 2023, 45 patients underwent cranio-maxillo-facial reconstructions with PSIs. Patients aged 18 years or older, with a minimum follow-up period of 12 months, were included. The morpho-functional outcome was evaluated through a modified Katsuragy Scale, the Visual Analogue Scale (VAS) for pain, and four FACE-Q|Aesthetics© scales.

RESULTS

In total, 44 PSIs were placed in 37 patients (51.3% males; mean age 45.1 years). The main cause of the defect was the resection of a tumor (55.4%). Mean follow-up was 78.6 months. Clinical evaluations showed an improvement in the postoperative period both in patient's and surgeon's scores (p: 0.01 and p: 0.002, respectively). Subgroup analysis confirmed a significant improvement in patients undergoing cranioplasty (p = 0.02) and mandible reconstruction (p = 0.03). No cases of prosthesis dislocation, rupture, or long-term infection were recorded.

CONCLUSIONS

PEEK PSIs offer significant advantages in craniofacial reconstructions. Despite challenges in predicting soft tissue adaptation, overall patient satisfaction was high with no long-term complications. Future improvements should focus on predicting and enhancing soft tissue adaptations.

An Unusual Case of Fibrous Dysplasia, Temporomandibular Joint Ankylosis, and Eagle's Syndrome

Fibrous dysplasia is a benign bone disease in children and young adults. This is characterized by the replacement of normal bone with fibrous tissue along with immature woven bone. Fibrous dysplasia is a rare disorder and has variable presentations that pose challenges in diagnosis and treatment. Decisions are made on a case-by-case basis, depending on the symptoms, location, or possible complications. Symptomatic lesions are treated with surgical resection. cosmetic concerns of the patients are taken care of by surgical contouring. For any unresectable or recurrent lesion, bisphosphonate therapy can be used as a form of medical management.

Digital technology revolutionizing mandibular fracture treatment: a comparative analysis of patient-specific plates and conventional titanium plates

OBJECTIVES

The treatment of fractures prioritizes the restoration of functionality through the realignment of fractured segments. Conventional methods, such as titanium plates, have been employed for this purpose; however, certain limitations have been observed, leading to the development of patient-specific plates. Furthermore, recent advancements in digital technology in dentistry enable the creation of virtual models and simulations of surgical procedures. The aim was to assess the clinical effectiveness of patient-specific plates utilizing digital technology in treating mandibular fractures compared to conventional titanium plates.

MATERIALS AND METHODS

Twenty patients diagnosed with mandibular fractures were included and randomly assigned to either the study or control groups. The surgical procedure comprised reduction and internal fixation utilizing patient-specific plates generated through virtual surgery planning with digital models for the study group, while the control group underwent the same procedure with conventional titanium plates. Assessment criteria included the presence of malunion, infection, sensory disturbance, subjective occlusal disturbance and occlusal force in functional maximum intercuspation (MICP). Statistical analysis involved using the Chi-square test and one-way repeated measures analysis of variance.

RESULTS

All parameters showed no statistically significant differences between the study and control groups, except for the enhancement in occlusal force in functional MICP, where a statistically significant difference was observed (p = 0.000).

CONCLUSION

Using patient-specific plates using digital technology has demonstrated clinical effectiveness in treating mandibular fractures, offering advantages of time efficiency and benefits for less experienced surgeons.

CLINICAL RELEVANCE

Patient-specific plates combined with digital technology can be clinically effective in mandibular fracture treatment.

The role of patient specific implants in the oral and maxillofacial region

Reconstructing maxillofacial defects is quiet challenging due to the region's complex anatomy, and cosmetic and functional effects on patients. With the help of developing technologies, patient-specific implants (PSIs) using virtual surgical planning based on a Computer aided designing (CAD)/Computer aided manufacturing (CAM) platform is an evolving treatment option. PSIs can be used in patients with maxillofacial defects and reconstruction. PSIs are also being used in the form of preformed plates for virtually planned orthognathic surgeries. Customized temporomandibular joint (TMJ) prosthesis is being routinely used in the debilitating/degenerative joint disease as a part of alloplastic joint replacement. The reconstruction of the maxillofacial region using autogenous tissue will always be gold standard due to near match of the recipient site. However, autogenous bone grafts positioned using PSIs or in certain areas such as the TMJ complex and the orbital region the PSIs are being offered with advantage of reduced donor-site morbidity. The future research is focussed towards the development of PSIs being used as a scaffold for engineering of the recipient tissue to restore the lost anatomy of specific region. This article reviews the varied aspects of this new technology of PSI for correction of various deformities/defects during the maxillofacial reconstruction.

Reconstruction of Craniomaxillofacial Bone Defects with 3D-Printed Bioceramic Implants: Scoping Review and Clinical Case Series

Reconstruction of craniomaxillofacial bone defects using 3D-printed hydroxyapatite (HA) bioceramic patient-specific implants (PSIs) is a new technique with great potential. This study aimed to investigate the advantages, disadvantages, and clinical outcomes of these implants in craniomaxillofacial surgeries. The PubMed and Embase databases were searched for patients with craniomaxillofacial bone defects treated with bioceramic PSIs. Clinical outcomes such as biocompatibility, biomechanical properties, and aesthetics were evaluated and compared to those of commonly used titanium or poly-ether-ether-ketone (PEEK) implants and autologous bone grafts. Two clinical cases are presented to illustrate the surgical procedure and clinical outcomes of HA bioceramic PSIs. Literature review showed better a biocompatibility of HA PSIs than titanium and PEEK. The initial biomechanical properties were inferior to those of autologous bone grafts, PEEK, and titanium but improved when integrated. Satisfactory aesthetic results were found in our two clinical cases with good stability and absence of bone resorption or infection. Radiological signs of osteogenesis were observed in the two clinical cases six months postoperatively. HA bioceramic PSIs have excellent biocompatible properties and imitate natural bone biomechanically and radiologically. They are a well-suited alternative for conventional biomaterials in the reconstruction of load-sharing bone defects in the craniomaxillofacial region.

An innovative 3D hydroxyapatite patient-specific implant for maxillofacial bone reconstruction: A case series of 13 patients

The study aimed to evaluate and discuss the use of an innovative PSI made of porous hydroxyapatite, with interconnected porosity promoting osteointegration, called MyBone Custom® implant (MBCI), for maxillofacial bone reconstruction. A multicentric cohort of 13 patients underwent maxillofacial bone reconstruction surgery using MBCIs for various applications, from genioplasty to orbital floor reconstruction, including zygomatic and mandibular bone reconstruction, both for segmental defects and bone augmentation. The mean follow-up period was 9 months (1-22 months). No infections, displacements, or postoperative fractures were reported. Perioperative modifications of the MBCIs were possible when necessary. Additionally, surgeons reported significant time saved during surgery. For patients with postoperative CT scans, osteointegration signs were visible at the 6-month postoperative follow-up control, and continuous osteointegration was observed after 1 year. The advantages and disadvantages compared with current techniques used are discussed. MBCIs offer new bone reconstruction possibilities with long-term perspectives, while precluding the drawbacks of titanium and PEEK. The low level of postoperative complications associated with the high osteointegration potential of MBCIs paves the way to more extensive use of this new hydroxyapatite PSI in maxillofacial bone reconstruction.

Three-dimensional measurements of symmetry for the mandibular ramus

BACKGROUND

The study examines a sample of patients presenting for viscerocranial computer tomography that does not display any apparent signs of asymmetry, assesses the three-dimensional congruency of the mandibular ramus, and focuses on differences in age and gender.

METHODS

This cross-sectional cohort study screened viscerocranial CT data of patients without deformation or developmental anomalies. Segmentations were obtained from the left and right sides and superimposed according to the best-fit alignment. Comparisons were made to evaluate three-dimensional congruency and compared between subgroups according to age and gender.

RESULTS

Two hundred and sixty-eight patients were screened, and one hundred patients met the inclusion criteria. There were no statistical differences between the left and right sides of the mandibular ramus. Also, there were no differences between the subgroups. The overall root mean square was 0.75 ± 0.15 mm, and the mean absolute distance from the mean was 0.54 ± 0.10 mm.

CONCLUSION

The mean difference was less than one millimetre, far below the two-millimetre distance described in the literature that defines relative symmetry. Our study population displays a high degree of three-dimensional congruency. Our findings help to understand that there is sufficient three-dimensional congruency of the mandibular ramus, thus contributing to facilitating CAD-CAM-based procedures based on symmetry for this specific anatomic structure.

Applications of Preoperative and Intraoperative Technologies for Complex Primary and Secondary Facial Trauma Reconstruction

This article provides a review of the current technologies available in the preoperative and intraoperative management of complex and secondary maxillofacial trauma reconstruction. These patients present a unique challenge for which the advancement of imaging technologies, patient-specific modeling and implants, and intraoperative imaging and navigation can play an important role to improve their post-treatment outcomes.

Patient-Specific Implants for Correction of Midfacial Aging

The nasolabial folds (NLFs) may be shallowed with the use of nostril base augmentation. This study aimed to design and customize patient-specific implants (PSIs) with computer-aided design/computer-aided manufacturing (CAD/CAM) to correct NLF deepening caused by midfacial aging. The patient's head computed tomography data obtained and were used for reconstruction. The PSIs were customized by CAD/CAM techniques, which were implanted into a nasal base for shallow NLFs caused by midfacial aging. Preoperative and postoperative photos and a wrinkle severity rating scale were used to evaluate the changes in NLFs. Also, the global esthetic improvement scale was used to investigate the surgical satisfaction of patients. Eleven patients (22 NLFs) received PSIs in the nasal base (22 implants). The customized PSI matched well with premaxilla, reducing the difficulty of operation. After 3 to 12 months of follow-up, PSI was stable without foreign body reaction or inflammatory reaction. Postoperative wrinkle severity rating scale scores showed that NLF severity was reduced in all patients, with a significant esthetic improvement compared with preoperatively ( P < 0.01). The global esthetic improvement scale showed an extremely satisfied improved NLF in 27.27% of patients, much improved in 63.63%, and improved in 9.90% (2/22), and none reported change or poor NLF. Patient satisfaction with their midface appearance differed significantly before and after surgery ( P < 0.01). Individualized PSI designed with high precision and matching degree by CAD and prepared using CAM could be applied to overcome the limitations of noncustomized implants.

The Use of 3D Technology in the Management of Residual Asymmetry following Orthognathic Surgery: A Case Report

The purpose of this case report was to present the aesthetic result of the reconstruction of facial residual asymmetry after orthognathic surgery using a patient-specific three-dimensional (3D) mold and a custom-made polymethyl methacrylate implant. Through computer-aided design (CAD), the healthy contralateral side of the mandible was superimposed onto the side with the defect. Exocad Gallway (exocad GmbH, Darmstadt, Germany) was used to design the patient-specific implants (PSIs) of the right mandibular angle. Next, the implant mold was created using the Meshmixer software (Version 3.5, Autodesk Inc., San Rafael, CA, USA) and fabricated using additive manufacturing. During the surgical procedure, the patient-specific implant (PSI) was cast inside the resin mold using Simplex P bone cement (Stryker, Mahwah, NJ, USA). The implant was fixed using three screws. Combining both indirect (involving the dental laboratory) and direct (with surgical intervention) approaches, this innovative hybrid method, which incorporates both computer-aided design and additive manufacturing (AM), not only enhanced facial aesthetics, functional rehabilitation, and patient quality of life but also mitigated the potential risks linked to conventional grafting methods.

Polyetheretherketone (PEEK) as a Potential Material for the Repair of Maxillofacial Defect Compared with E-poly(tetrafluoroethylene) (e-PTFE) and Silicone

Silicone and e-poly(tetrafluoroethylene) (e-PTFE) are the most commonly used artificial materials for repairing maxillofacial bone defects caused by facial trauma and tumors. However, their use is limited by poor histocompatibility, unsatisfactory support, and high infection rates. Polyetheretherketone (PEEK) has excellent mechanical strength and biocompatibility, but its application to the repair of maxillofacial bone defects lacks a theoretical basis. The microstructure and mechanical properties of e-PTFE, silicone, and PEEK were evaluated by electron microscopy, BOSE machine, and Fourier transformed infrared spectroscopy. Mouse fibroblast L929 cells were incubated on the surface of the three materials to assess cytotoxicity and adhesion. The three materials were implanted onto the left femoral surface of 90 male mice, and samples of the implants and surrounding soft tissues were evaluated histologically at 1, 2, 4, 8, and 12 weeks post-surgery. PEEK had a much higher Young's modulus than either e-PTFE or silicone (p < 0.05 each), and maintained high stiffness without degradation long after implantation. Both PEEK and e-PTFE facilitated L929 cell adhesion, with PEEK having lower cytotoxicity than e-PTFE and silicone (p < 0.05 each). All three materials similarly hindered the motor function of mice 12 weeks after implantation (p > 0.05 each). Connective tissue ingrowth was observed in PEEK and e-PTFE, whereas a fibrotic peri-prosthetic capsule was observed on the surface of silicone. The postoperative infection rate was significantly lower for both PEEK and silicone than for e-PTFE (p < 0.05 each). PEEK shows excellent biocompatibility and mechanical stability, suggesting that it can be effective as a novel implant to repair maxillofacial bone defects.

Patient-Specific Implants in Maxillofacial Reconstruction - A Case Report

Rationale

The successful utilisation of three dimensional (3D) techniques in engineering a titanium patient specific implant (PSI) for a patient who underwent hemimaxillectomy following post COVID mucormycosis infection.

Patient Concerns

Issues related to problems associated with resection following mucormycosis, such as occlusal function, aesthetics and facial asymmetry.

Diagnosis

The patient affected by mucormycosis was left with Aramany class 1 and Cordeiro type II sub total maxillectomy defect.

Treatment

The patient was operated for mucormycosis followed by reconstruction with patient specific implant.

Outcome

Positive clinical outcomes, including improved facial symmetry, function and psychological well being with immediate replacement of the teeth, the benefits of which far outweigh the traditional approach.

Take away Lessons

The advances in the use of PSI by integration of 3D printing and computer aided design computer aided manufacturing (CAD-CAM) technology for extensive and challenging defects in the maxillofacial region have been highlighted in this case report.

Segmental Resection With Primary Reconstruction Using a Patient-Specific Implant for Unicystic Ameloblastoma: A One-Year Follow-Up Case Report

Unicystic ameloblastoma is a slow-growing tumor originating from the odontogenic epithelium that can be localized within the lining of a cyst. It commonly affects younger individuals and is frequently found in the posterior mandible. The classification of this tumor is based on histopathological characteristics, distinguishing between the luminal, intraluminal, and mural proliferation of the odontogenic epithelium. Treatment options vary depending on the histology and can range from enucleation to resection with secondary reconstruction. In recent years, patient-specific implants have gained popularity in reconstructive surgeries, particularly in craniomaxillofacial surgery. This case report focuses on a 22-year-old female patient with a mural-type unicystic ameloblastoma. The treatment involved segmental mandibular resection with primary reconstruction using a patient-specific implant to address the mandibular defect. The postoperative healing process and condylar movement were evaluated, and the patient achieved satisfactory results. This case report provides valuable insights into the management of primary reconstruction using a patient-specific implant.

Vertical augmentation of a severely atrophied posterior mandibular alveolar ridge for a dental implant using a patient-specific 3D printed PCL/BGS7 scaffold: A technical note

Vertical bone augmentation for dental implants in the posterior mandibular region with significant bone resorption is challenging. For this purpose, methods such as block bone grafting with screw fixation, particulate bone grafting with titanium mesh or barrier membrane, and distraction osteogenesis have been used, and autogenous block bone grafting is considered the gold standard. However, the autogenous block bone grafting has the following disadvantages: bone harvesting is challenging, and block bone contouring according to the recipient site is time-consuming and laborious. Therefore, in this study, we report the use of particulate bone with a polycaprolactone/bioactive glass-7 scaffold, designed, and three-dimensionally printed preoperatively, to resolve the above-mentioned challenges.

Can Steam Sterilization Affect the Accuracy of Point-of-Care 3D Printed Polyetheretherketone (PEEK) Customized Cranial Implants? An Investigative Analysis

Polyetheretherketone (PEEK) has become the biomaterial of choice for repairing craniofacial defects over time. Prospects for the point-of-care (POC) fabrication of PEEK customized implants have surfaced thanks to the developments in three-dimensional (3D) printing systems. Consequently, it has become essential to investigate the characteristics of these in-house fabricated implants so that they meet the necessary standards and eventually provide the intended clinical benefits. This study aimed to investigate the effects of the steam sterilization method on the dimensional accuracy of POC 3D-printed PEEK customized cranial implants. The objective was to assess the influence of standard sterilization procedures on material extrusion-based 3D-printed PEEK customized implants with non-destructive material testing. Fifteen PEEK customized cranial implants were fabricated using an in-house material extrusion-based 3D printer. After fabrication, the cranial implants were digitalized with a professional-grade optical scanner before and after sterilization. The dimensional changes for the 3D-printed PEEK cranial implants were analyzed using medically certified 3D image-based engineering software. The material extrusion 3D-printed PEEK customized cranial implants displayed no statistically significant dimensional difference with steam sterilization (p > 0.05). Evaluation of the cranial implants’ accuracy revealed that the dimensions were within the clinically acceptable accuracy level with deviations under 1.00 mm. Steam sterilization does not significantly alter the dimensional accuracy of the in-house 3D-printed PEEK customized cranial implants.

Familial Gigantiform Cementoma: Life-Saving Total Midface Resection and Reconstruction Using Virtual Surgical Planning and 3D Printed Patient-Specific Implant-A Clinical Study

Background

Familial gigantiform cementoma (FGC) is a rare benign fibrocemento-osseous lesion of the jaw characterized by well-circumscribed, extensive, mixed radiolucent-radiopaque masses in the mandible and the maxilla that can cause severe facial deformity. This condition is extremely rare with less than 40 cases reported in the literature.

Purpose

The purpose of the paper is to highlight the importance of virtual surgical planning and patient-specific implant in the treatment of a complex lesion and reconstruction of the facial skeleton. The clinical presentations, and diagnostic challenges encountered when managing the lesion have been discussed in this article with emphasis on the treatment plan.

Method/Surgical plan

The sequence of treatment planned was resection of the lesion and immediate reconstruction with a patient-specific implant to improve the patient's quality of life. The management of FGC was a challenging one keeping in mind the rapid expansion of the lesion, widespread involvement of the jaws, and needs of the pediatric patient.

Conclusion

Virtual surgical planning (VSP) along with 3D printed implant was instrumental in reconstructing the facial form of the child where the maxilla was completely resected and rehabilitation provided support to the vital structures of the face.

Investigating the accuracy of mandibulectomy and reconstructive surgery using 3D customized implants and surgical guides in a rabbit model

BACKGROUND

This study aimed to analyze the accuracy of the output of three-dimensional (3D) customized surgical guides and titanium implants in a rabbit model, and of mandibulectomy, reconstructive surgery, and surgical outcome; additionally, the correlation between surgical accuracy and surgical outcomes, including the differences in surgical outcome according to surgical accuracy, was analyzed.

RESULTS

The output of implants was accurately implemented within the error range (- 0.03-0.03 mm), and the surgical accuracy varied depending on the measured area (range - 0.4-1.1 mm). Regarding surgical outcomes, angle between the mandibular lower borders showed the most sensitive results and distance between the lingual cusps of the first molars represented the most accurate outcomes. A significant correlation was noted between surgical accuracy in the anteroposterior length of the upper borders pre- and postoperatively and the angle between the mandibular lower borders (regression coefficient = 0.491, p = 0.028). In the group wherein surgery was performed more accurately, the angle between the mandibular lower borders was reproduced more accurately (p = 0.021). A selective laser melting machine accurately printed the implants as designed. Considering the positive correlation among surgical accuracy in the mandibular upper borders, angle between the mandibular lower borders, and more accurately reproduced angle between the mandibular lower borders, the angle between the mandibular lower borders is considered a good indicator for evaluating the outcomes of reconstructive surgery.

CONCLUSION

To reduce errors in surgical outcomes, it is necessary to devise a positioner for the surgical guide and design a 3D surgical guide to constantly maintain the direction of bone resection. A fixed area considering the concept of three-point fixation should be selected for stable positioning of the implant; in some cases, bilateral cortical bone fixation should be considered. The angle between the mandibular lower borders is a sensitive indicator for evaluating the outcomes of reconstructive surgery.

3D printed plates based on generative design biomechanically outperform manual digital fitting and conventional systems printed in photopolymers in bridging mandibular bone defects of critical size in dogs

Conventional plate osteosynthesis of critical-sized bone defects in canine mandibles can fail to restore former functionality and stability due to adaption limits. Three-dimensional (3D) printed patient-specific implants are becoming increasingly popular as these can be customized to avoid critical structures, achieve perfect alignment to individual bone contours, and may provide better stability. Using a 3D surface model for the mandible, four plate designs were created and evaluated for their properties to stabilize a defined 30 mm critical-size bone defect. Design-1 was manually designed, and further shape optimized using Autodesk ^® Fusion 360 (ADF360) and finite element analysis (FE) to generate Design-2. Design-4 was created with the generative design (GD) function from ADF360 using preplaced screw terminals and loading conditions as boundaries. A 12-hole reconstruction titanium locking plate (LP) (2.4/3.0 mm) was also tested, which was scanned, converted to a STL file and 3D printed (Design-3). Each design was 3D printed from a photopolymer resin (VPW) and a photopolymer resin in combination with a thermoplastic elastomer (VPWT) and loaded in cantilever bending using a customized servo-hydraulic mechanical testing system; n = 5 repetitions each. No material defects pre- or post-failure testing were found in the printed mandibles and screws. Plate fractures were most often observed in similar locations, depending on the design. Design-4 has 2.8-3.6 times ultimate strength compared to other plates, even though only 40% more volume was used. Maximum load capacities did not differ significantly from those of the other three designs. All plate types, except D3, were 35% stronger when made of VPW, compared to VPWT. VPWT D3 plates were only 6% stronger. Generative design is faster and easier to handle than optimizing manually designed plates using FE to create customized implants with maximum load-bearing capacity and minimum material requirements. Although guidelines for selecting appropriate outcomes and subsequent refinements to the optimized design are still needed, this may represent a straightforward approach to implementing additive manufacturing in individualized surgical care. The aim of this work is to analyze different design techniques, which can later be used for the development of implants made of biocompatible materials.

Case report: Reconstruction of a complex maxillofacial gunshot defect using a titanium patient-specific implant in a dog

This report describes the surgical reconstruction of large maxillofacial defect caused by a short-range gunshot injury in a dog using titanium patient-specific implant (PSI). A 3-year-old male Wolf Shepherd was admitted for a large right facial defect with right nasal cavity exposure caused by a gunshot injury. Radiographic examination revealed severe loss of the right maxillary, nasal, and incisive bones, multiple fractures of both left and right palatine bones, and a comminuted fracture of the right mandible. Initial surgical procedure included computed tomography (CT) imaging for three-dimensional (3D) implant design. Open wound management was maintained for 18 days until the fresh granulation tissue fully covered the wound bed. The implant was designed in a “hand grasping shape” to cover the defect, align multiple fractured palatine bones, and make a snap fit function. Multiple holes, including cortical screw holes, were added to the final design. The implant was printed on a titanium alloy. Surgical application of titanium PSI was performed 19 days after the primary surgery. A free sublingual mucosal graft was used to reconstruct the mucosal layer of the right nasal cavity. The mucosa was then covered with collagen membrane to strengthen the structure of the nasal cavity. Blunt dissection of the hard palate mucoperiosteum above the palatine process and palatine bones, soft tissue above the maxilla was performed, and the 3D printed titanium implant was fastened in a preplanned position. The facial soft tissue defect was reconstructed, and the titanium PSI was covered using an angularis oris cutaneous flap. Partial flap necrosis occurred in the rostral aspect, and the wound was managed to heal by a second intension. Flap dehiscence at the junction of the flap and hard palate mucoperiosteum occurred with exposure of the implant 2 days postoperatively. Multiple attempts to close the defect failed, and the owner wanted to stop treatment. Healthy granulated tissue was observed proximal to the implant. The defect no longer increased in size and did not show any noticeable complications related to the defect at 60 days after titanium PSI application, and the dog was discharged. Six months post-operatively, the dog remained active with great appetite, gained weight, and showed acceptable facial symmetry without enlargement of the implant exposure or any implant-related problems.

Simultaneous PSI-Based Orthognathic and PEEK Bone Augmentation Surgery Leads to Improved Symmetric Facial Appearance in Craniofacial Malformations

(1) The aim of the present study was to compare the outcome of facial symmetry after simultaneous digitally planned patient-specific implant (PSI-) based orthognathic surgery and polyether ether ketone (PEEK) bone augmentation in patients with craniofacial malformations. (2) To evaluate the outcome of the two different surgical approaches (conventional PSI-based orthognathic surgery versus simultaneous PSI-based orthognathic surgery with PEEK bone augmentation), a comparison of five different groups with a combination of the parameters (A) with vs. without laterognathia, (B) syndromic vs. non-syndromic, and (C) surgery with vs. without PEEK bone augmentation was conducted. The digital workflow comprised cone beam CT (CBCT) scans and virtual surgery planning for all patients in order to produce patient specific cutting guides and osteosynthesis plates. Additionally, deformed skulls were superimposed by a non-deformed skull and/or the healthy side was mirrored to produce PSI PEEK implants for augmentation. Retrospective analyses included posterior-anterior conventional radiographs as well as en face photographs taken before and nine months after surgery. (3) Simultaneous orthognathic surgery with PEEK bone augmentation significantly improves facial symmetry compared to conventional orthognathic surgery (6.5%P (3.2-9.8%P) (p = 0.001). (4) PSI-based orthognathic surgery led to improved horizontal bone alignment in all patients. Simultaneous PEEK bone augmentation enhanced facial symmetry even in patients with syndrome-related underdevelopment of both soft and hard tissues.

Preservation of Infraorbital Nerve in Orbital Floor and Maxillary Defect Reconstruction With Patient-Specific Three-Dimensional Implant: A Case Report

Reconstruction of orbitomaxillary defects poses many operative challenges because it requires consideration of cosmetic as well as functional elements: reestablishing facial symmetry while constituting the orbital volume and preserving involved neurovascular structures. The development of patient-specific polyetheretherketone implants have revolutionized complex craniofacial reconstruction due to its adaptability to anatomic constraints and accommodation of vital structures. Herein, we described 2 cases of orbitomaxillary reconstruction using PEEK implant with novel modifications to preserve the infraorbital nerve with optimal cosmetic outcomes and minimal postoperative morbidity.

Evaluating patients’ satisfaction level after using 3D printed PEEK facial implants in repairing maxillofacial deformities

Background

it is generally the case in any traumatic accident where a loss in hard tissue occurs to preform restorative plastic surgery, as there are many materials and approaches used to restore the loss, this research sheds the light on the use of one such material and approach being 3D printed facial implants manufactured from PolyEther Ether Ketone (PEEK) and to evaluate the level of patients’ satisfaction following the use of said method in repairing maxillofacial deformities.

Materials and methods

a research sample consisting of 10 patients with facial deformities underwent maxillofacial reconstructive surgery between 2020 and 2021 in the Department of Oral and Maxillofacial Surgery in the Tishreen University Hospital - Latakia - Syria. All patients underwent Computed Tomography (CT) scans, then the design of the required facial implant was carried out, the final form of the facial implant was printed from PolyEther Ether Ketone (PEEK), and then surgical work was performed, a check-up after 3 months of the surgical procedure was carried out to evaluate the level of satisfaction on a scale of 1–5.

Results

The results from the 10 patients showed a good level of satisfaction except in one case where the facial implant had to be removed due to recurrent infection where the patient showed no signs of response to medicinal treatment following the surgery.

Conclusions

this research suggests that the use of 3D printed PEEK facial implants to be very agreeable in terms of functionality and aesthetics in treating various facial deformities.

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3D Printed PEEK PSIs implants are used for repairing facial injuries.

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PEEK implants are very good means to achieve acceptable aesthetic results.

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The use of the method is very convenient and saves time and effort.

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After surgery results were mostly pleasing.

Reconstruction of maxillofacial bone defects using patient-specific long-lasting titanium implants

The objective of this retrospective study is to verify the effectiveness and safety of patient-specific titanium implants on maxillofacial bones, with a long-term follow-up. Total 16 patients with various maxillofacial defects underwent reconstruction using patient-specific titanium implants. Titanium implants, manufactured by electron beam melting, selective laser sintering, or milling, were inserted into the maxilla, mandible, or zygoma. Long-term follow‐up (36.7 ± 20.1 months) was conducted after the surgery. Bone fusion of the titanium implant body, postoperative infection, implant malunion, functional results, patient satisfaction, subsidence, osteolysis around the implants, and complications were recorded and analyzed at the last follow-up. Of the 28 implants, only one failed to unite with the bone; therefore, revision surgery was performed. No osteolysis or subsidence around the titanium implants nor adverse events were observed; the mean VAS score for satisfaction was 9. All patients enrolled in this trial were esthetically and functionally satisfied with their surgical results, and fixation failure and esthetic dissatisfaction complications were well resolved. Patient-specific titanium showed satisfactory outcomes when used to treat various oral and maxillofacial defects. A 3D printed titanium implant can be effectively used in the reconstruction of the zygoma and mandible instead of autogenous bone without donor site morbidity.

Bone Regeneration of a 3D-Printed Alloplastic and Particulate Xenogenic Graft with rhBMP-2

This study aimed to evaluate the bone regeneration capacity of a customized alloplastic material and xenograft with recombinant human bone morphogenetic protein-2 (rhBMP-2). We prepared hydroxyapatite (HA)/tricalcium phosphate (TCP) pure ceramic bone blocks made using a 3D printing system and added rhBMP-2 to both materials. In eight beagle dogs, a total of 32 defects were created on the lower jaws. The defective sites of the negative control group were left untreated (N group; 8 defects), and those in the positive control group were filled with particle-type Bio-Oss (P group; 12 defects). The defect sites in the experimental group were filled with 3D-printed synthetic bone blocks (3D group; 12 defects). Radiographic and histological evaluations were performed after healing periods of 6 and 12 weeks and showed no significant difference in new bone formation and total bone between the P and 3D groups. The 3D-printed custom HA/TCP graft with rhBMP-2 showed bone regeneration effects similar to that of particulate Bio-Oss with rhBMP-2. Through further study and development, the application of 3D-printed customized alloplastic grafts will be extended to various fields of bone regeneration.

Biomechanical comparison of locking and non-locking patient-specific mandibular reconstruction plate using finite element analysis

Patient-specific mandibular reconstruction plate (PSMRP), as one of the patient-specific implants (PSIs), offers a host of benefits to mandibular reconstruction. Due to the limitation of fabricating screw hole threads in the PSMRP, 3D printed PSMRP is applied to the non-locking system directly in the mandibular reconstruction with bone graft regardless of the locking system. Since the conventional manual-bending reconstruction plate (CMBRP) provides better fixation in the locking system, it needs to be validated whether the locking PSMRP performs better than the non-locking PSMRP in the patient-specific mandibular reconstruction. Thereupon, the purpose of this study was to compare the biomechanical behavior between the locking and non-locking PSMRP. Finite element analysis (FEA) was used to conduct the biomechanical comparison between the locking PSMRP and non-locking PSMRP by simulating the momentary incisal clenching through static structural analysis. Mandible was reconstructed through the virtual surgical planning, and subsequently a 3D model of mandibular reconstruction assembly, including reconstructed mandible, PSMRP, and fixation screws, was generated and meshed for the following FEA simulations. In the form of equivalent von Mises stress, equivalent elastic strain, and total deformation, the locking PSMRP demonstrated its higher strengths of preferable safety, desirable flexibility, and anticipated stability compared with the non-locking PSMRP, indicated by much lower maximum stress, lower maximum strain and equivalent displacement. Locking PSMRP/screw system provides a better fixation effect to the patient-specific mandibular reconstruction than the non-locking one as a result of its productive fixation nature. FEA plays a paramount role in pre-validating the design of PSMRP through the biomechanical behavior evaluation in static structural analysis.

A Multi-Criteria Assessment Strategy for 3D Printed Porous Polyetheretherketone (PEEK) Patient-Specific Implants for Orbital Wall Reconstruction

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient's unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

Quantitative Assessment of Point-of-Care 3D-Printed Patient-Specific Polyetheretherketone (PEEK) Cranial Implants

Recent advancements in medical imaging, virtual surgical planning (VSP), and three-dimensional (3D) printing have potentially changed how today's craniomaxillofacial surgeons use patient information for customized treatments. Over the years, polyetheretherketone (PEEK) has emerged as the biomaterial of choice to reconstruct craniofacial defects. With advancements in additive manufacturing (AM) systems, prospects for the point-of-care (POC) 3D printing of PEEK patient-specific implants (PSIs) have emerged. Consequently, investigating the clinical reliability of POC-manufactured PEEK implants has become a necessary endeavor. Therefore, this paper aims to provide a quantitative assessment of POC-manufactured, 3D-printed PEEK PSIs for cranial reconstruction through characterization of the geometrical, morphological, and biomechanical aspects of the in-hospital 3D-printed PEEK cranial implants. The study results revealed that the printed customized cranial implants had high dimensional accuracy and repeatability, displaying clinically acceptable morphologic similarity concerning fit and contours continuity. From a biomechanical standpoint, it was noticed that the tested implants had variable peak load values with discrete fracture patterns and failed at a mean (SD) peak load of 798.38 ± 211.45 N. In conclusion, the results of this preclinical study are in line with cranial implant expectations; however, specific attributes have scope for further improvements.

Quality Characteristics and Clinical Relevance of In-House 3D-Printed Customized Polyetheretherketone (PEEK) Implants for Craniofacial Reconstruction

Additive manufacturing (AM) of patient-specific implants (PSIs) is gradually moving towards in-house or point-of-care (POC) manufacturing. Polyetheretherketone (PEEK) has been used in cranioplasty cases as a reliable alternative to other alloplastic materials. As only a few fused filament fabrication (FFF) printers are suitable for in-house manufacturing, the quality characteristics of the implants fabricated by FFF technology are still under investigated. This paper aimed to investigate PEEK PSIs fabricated in-house for craniofacial reconstruction, discussing the key challenges during the FFF printing process. Two exemplary cases of class III (Group 1) and class IV (Group 2) craniofacial defects were selected for the fabrication of PEEK PSIs. Taguchi’s L9 orthogonal array was selected for the following nonthermal printing process parameters, i.e., layer thickness, infill rate, number of shells, and infill pattern, and an assessment of the dimensional accuracy of the fabricated implants was made. The root mean square (RMS) values revealed higher deviations in Group 1 PSIs (0.790 mm) compared to Group 2 PSIs (0.241 mm). Horizontal lines, or the characteristic FFF stair-stepping effect, were more perceptible across the surface of Group 1 PSIs. Although Group 2 PSIs revealed no discoloration, Group 1 PSIs displayed different zones of crystallinity. These results suggest that the dimensional accuracy of PSIs were within the clinically acceptable range; however, attention must be paid towards a requirement of optimum thermal management during the printing process to fabricate implants of uniform crystallinity.

Patient-Specific Surgical Implant Using Cavity-Filled Approach for Precise and Functional Mandible Reconstruction

Mandibular reconstruction is a complicated task because of the complex nature of the regional anatomy. Computer-assisted tools are a promising means of improving the precision and safety of such complex surgeries. The digital techniques utilized in the reconstruction of mandibular defects based on medical data, computer-aided-design approaches, and three-dimensional (3D) printing are widely used to improve the patient’s aesthetic appearance and function, as well as the accuracy and quality of diagnosis, and surgical outcomes. Nevertheless, to ensure an acceptable aesthetical appearance and functional outcomes, the design must be based on proper anatomical reconstruction, mostly done in a virtual environment by skilled design engineers. Mirroring is one of the widely used techniques in the surgical navigation and reconstruction of mandibular defects. However, there are some discrepancies and mismatches in the mirrored anatomical models. Hence, in order to overcome these limitations in the mirroring technique, a novel approach called the cavity-filled technique was introduced. The objective of this study was to compare the accuracy of the newly recommended cavity-filled technique with the widely used mirror reconstruction technique in restoring mandibular defects. A prominent 3D comparison technique was employed in this work, where the resected and the reconstructed mandibles were superimposed to quantify the accuracy of the two techniques. From the analysis, it can be inferred that the cavity-filled technique with a root-mean-square value of 1.1019 mm produced better accuracy in contrast to the mirroring approach, which resulted in an error of 1.2683 mm. Consequently, by using the proposed cavity-filled design, the discrepancy between the reconstruction plate and the bone contour was mitigated. This method, owing to its high precision, can decrease the number of adjustments and the time of surgery, as well as ensure a quick recovery time with better implant tissue in-growth.