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

Tissue scaffolds mimicking hierarchical bone morphology as biomaterials for oral maxillofacial surgery with augmentation: structure, properties, and performance evaluation forin vitrotesting

In this study, tissue scaffolds mimicking hierarchical morphology are constructed and proposed for bone augmentation. The scaffolds are fabricated using lyophilization, before coating them with collagen (Col). Subsequently, the Col-coated scaffolds undergo a second lyophilization, followed by silk fibroin (SF) coating, and a third lyophilization. Thereafter, the scaffolds are divided into six groups with varying ratios of Col to SF: Col/SF = 7:3, 5:5, 3:7, 10:0, and 0:10, with an SF scaffold serving as the control group. The scaffold morphology is examined using a scanning electron microscope, while molecular and structural formations are characterized by Fourier transform infrared spectrometer and differential scanning calorimeter, respectively. Physical and mechanical properties including swelling and compression are tested. Biological functions are assessed throughin vitroosteoblast cell culturing. Biomarkers indicative of bone formation-cell viability and proliferation, alkaline phosphatase activity, and calcium content-are analyzed. Results demonstrate that scaffolds coated with Col and SF exhibit sub-porous formations within the main pore. The molecular formation reveals interactions between the hydrophilic groups of Col and SF. The scaffold structure contains bound water and SF formation gets disrupted by Col. Physical and mechanical properties are influenced by the Col/SF ratio and morphology due to coating. The biological functions of scaffolds with Col and SF coating show enhanced potential for promoting bone tissue formation, particularly the Col/SF (7:3) ratio, which is most suitable for bone augmentation in small defect areas.

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 use of customized 3D-printed mandibular prostheses with pressure-reducing device: A clinical trial

BACKGROUND

Segmental bone defects of the mandible result in the complete loss of the affected region. We had incorporated the pressure-reducing device (PRD) designs into the customized mandible prostheses (CMP) and conducted a clinical trial to evaluate this approach.

METHODS

Seven patients were enrolled in this study. We examined the association among the history of radiotherapy, the number of CMP regions, the number of chin regions involved, and CMP exposure.

RESULTS

We included five men and two women with an average age of 55 years. We excised tumors with an average weight of 147.8 g and the average weight of the CMP was 68.5 g. No significant difference between the two weights was noted (p = 0.3882). Three patients received temporary dentures and the CMP remained stable in all patients.

CONCLUSION

The use of PRD in CMP may address the previous challenges associated with CMP, but further research is necessary.

Senolytics ameliorate the failure of bone regeneration through the cell senescence-related inflammatory signalling pathway

Stress-induced premature senescent (SIPS) cells induced by various stresses deteriorate cell functions. Dasatinib and quercetin senolytics (DQ) can alleviate several diseases by eliminating senescent cells. α-tricalcium phosphate (α-TCP) is a widely used therapeutic approach for bone restoration but induces bone formation for a comparatively long time. Furthermore, bone infection exacerbates the detrimental prognosis of bone formation during material implant surgery due to oral cavity bacteria and unintentional contamination. It is essential to mitigate the inhibitory effects on bone formation during surgical procedures. Little is known that DQ improves bone formation in Lipopolysaccharide (LPS)-contaminated implants and its intrinsic mechanisms in the study of maxillofacial bone defects. This study aims to investigate whether the administration of DQ ameliorates the impairments on bone repair inflammation and contamination by eliminating SIPS cells. α-TCP and LPS-contaminated α-TCP were implanted into Sprague-Dawley rat calvaria bone defects. Simultaneously, bone formation in the bone defects was investigated with or without the oral administration of DQ. Micro-computed tomography and hematoxylin-eosin staining showed that senolytics significantly enhanced bone formation at the defect site. Histology and immunofluorescence staining revealed that the levels of p21- and p16-positive senescent cells, inflammation, macrophages, reactive oxygen species, and tartrate-resistant acid phosphatase-positive cells declined after administering DQ. DQ could partially alleviate the production of senescent markers and senescence-associated secretory phenotypes in vitro. This study indicates that LPS-contaminated α-TCP-based biomaterials can induce cellular senescence and hamper bone regeneration. Senolytics have significant therapeutic potential in reducing the adverse osteogenic effects of biomaterial-related infections and improving bone formation capacity.

New Innovation: Custom Titanium Zygomaticomaxillary Complex (ZMC) Plate for Facial Reconstruction

Zygomaticomaxillary complex (ZMC) fractures typically result from traumatic injuries, such as motor vehicle-related incidents, assaults, falls, and sports-related injuries. These fractures characteristically occur along suture lines where the zygomatic bone borders the frontal bone, maxilla, temporal bone, and sphenoid bone, resulting in a "tetrapod" fracture pattern that can be surgically fixated utilizing one, two, and three-point plate and screw fixation. However, fractures with complete loss of bone stock are less common, and standardized methods of fixation are not suitable for such complex fractures. Here, we present an interesting case of implantation of a custom-made alloplastic implant in a patient with complex ZMC fractures with loss of bone stock. A 52-year-old male sustained a traumatic gunshot wound to the face, resulting in significant destruction of bones involving the left orbital floor, left lateral orbital wall, and left zygomatic arch. Routine plating was not feasible, so a custom spanning plating system by DePuy Synthes (Synthes USA Products, LLC, West Chester, PA) was designed using the patient's CT scans. The patient recovered well with no complications. This case illustrates the successful application of patient-specific custom plates for complex ZMC fractures when standard plating methods are not suitable.

Utilization of 3D printing technology in hepatopancreatobiliary surgery

The technology of three-dimensional (3D) printing emerged in the late 1970s and has since undergone considerable development to find numerous applications in mechanical engineering, industrial design, and biomedicine. In biomedical science, several studies have initially found that 3D printing technology can play an important role in the treatment of diseases in hepatopancreatobiliary surgery. For example, 3D printing technology has been applied to create detailed anatomical models of disease organs for preoperative personalized surgical strategies, surgical simulation, intraoperative navigation, medical training, and patient education. Moreover, cancer models have been created using 3D printing technology for the research and selection of chemotherapy drugs. With the aim to clarify the development and application of 3D printing technology in hepatopancreatobiliary surgery, we introduce seven common types of 3D printing technology and review the status of research and application of 3D printing technology in the field of hepatopancreatobiliary surgery.

Total temporomandibular joint reconstruction prosthesis in hemifacial microsomia: A systematic review

Hypoplastic asymmetry due to hemifacial microsomia (HFM) often represents the most difficult reconstruction in the craniomaxillofacial clinic. Although autogenous grafts are generally used for temporomandibular joint reconstruction (TMJR), the use of TMJR prostheses is not well established. The aim of this review was to identify, collect and analyse the use of extended TMJR (eTMJR) prostheses in patients with HFM, describing clinical features, surgical procedures and postoperative complications. Online searches of all major databases were performed according to PRISMA guidelines. All studies with HFM patients treated with the eTMJR prostheses were included. Descriptive statistics were used for data analysis. A total of 19 studies, including 08 case studies, 06 case series and 05 retrospective cohort studies, met the inclusion criteria, where a total of 42 HFM patients were reported from 18 countries, mostly from the United States (05; 26%). Fifteen of the 42 cases (~36%) were male. The mean ± SD (range) age of patients in all studies was 19.79 ± 5.81 (9-36) years. The mean ± SD (range) of patient follow-up was 41.30 ± 35.50 (6-136) months. A total of 5 (10.6%) patients were implanted with bilateral eTMJR prostheses. The Pruzansky classification was used in 18 (~89.5%) studies, OMENS classification in 01 (~5%) study, whereas no classification was reported in one study. Only 01 (7.1%) study had documented the eTMJR classification for the prosthesis used. In growing patients with or without a history of failed autogenous tissues, TMJR prostheses may provide a viable alternative. Randomized studies with large cohorts are warranted to validate these preliminary results.

Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery

Advanced head and neck cancers involving the mandible often require surgical removal of the diseased parts and replacement with donor bone or prosthesis to recreate the form and function of the premorbid mandible. The degree to which this reconstruction successfully replicates key geometric features of the original bone critically affects the cosmetic and functional outcomes of speaking, chewing, and breathing. With advancements in computational power, biomechanical modeling has emerged as a prevalent tool for predicting the functional outcomes of the masticatory system and evaluating the effectiveness of reconstruction procedures in patients undergoing mandibular reconstruction surgery. These models offer cost-effective and patient-specific treatment tailored to the needs of individuals. To underscore the significance of biomechanical modeling, we conducted a review of 66 studies that utilized computational models in the biomechanical analysis of mandibular reconstruction surgery. The majority of these studies employed finite element method (FEM) in their approach; therefore, a detailed investigation of FEM has also been provided. Additionally, we categorized these studies based on the main components analyzed, including bone flaps, plates/screws, and prostheses, as well as their design and material composition.

Balancing beauty and science: a review of facial implant materials in craniofacial surgery

Facial reconstruction and augmentation, integral in facial plastic surgery, address defects related to trauma, tumors infections, and congenital skeletal deficiencies. Aesthetic considerations, including age-related facial changes, involve volume loss and diminished projection, often associated with predictable changes in the facial skeleton. Autologous, allogeneic, and alloplastic implants are used to address these concerns. Autologous materials such as bone, cartilage, and fat, while longstanding options, have limitations, including unpredictability and resorption rates. Alloplastic materials, including metals, polymers, and ceramics, offer alternatives. Metals like titanium are biocompatible and used primarily in fracture fixation. Polymers, such as silicone and polyethylene, are widely used, with silicone presenting migration, bony resorption, and visibility issues. Polyethylene, particularly porous polyethylene (MedPor), was reported to have one of the lowest infection rates while it becomes incorporated into the host. Polyether-ether-ketone (PEEK) exhibits mechanical strength and compatibility with imaging modalities, with custom PEEK implants providing stable results. Acrylic materials, like poly-methylmethacrylate (PMMA), offer strength and is thus mostly used in the case of cranioplasty. Bioceramics, notably hydroxyapatite (HaP), offer osteoconductive and inductive properties, and HaP granules demonstrate stable volume retention in facial aesthetic augmentation. Combining HaP with other materials, such as PLA, may enhance mechanical stability. 3D bioprinting with HaP-based bioinks presents a promising avenue for customizable and biocompatible implants. In conclusion, various materials have been used for craniofacial augmentation, but none have definitively demonstrated superiority. Larger randomized controlled trials are essential to evaluate short- and long-term complications comprehensively, potentially revolutionizing facial balancing surgery.

Research progress and perspective of metallic implant biomaterials for craniomaxillofacial surgeries

Craniomaxillofacial bone serves a variety of functions. However, the increasing number of cases of craniomaxillofacial bone injury and the use of selective rare implants make the treatment difficult, and the cure rate is low. If such a bone injury is not properly treated, it can lead to a slew of complications that can seriously disrupt a patient's daily life. For example, premature closure of cranial sutures or skull fractures can lead to increased intracranial pressure, which can lead to headaches, vomiting, and even brain hernia. At present, implant placement is one of the most common approaches to repair craniomaxillofacial bone injury or abnormal closure, especially with biomedical metallic implants. This review analyzes the research progress in the design and development of degradable and non-degradable metallic implants in craniomaxillofacial surgery. The mechanical properties, corrosion behaviours, as well as in vitro and in vivo performances of these materials are summarized. The challenges and future research directions of metallic biomaterials used in craniomaxillofacial surgery are also identified.

Shaping the Future of Cardiovascular Disease by 3D Printing Applications in Stent Technology and its Clinical Outcomes

Cardiovascular disease (CVD) is a leading cause of death worldwide. In recent years, 3D printing technology has ushered in a new era of innovation in cardiovascular medicine. 3D printing in CVD management encompasses various aspects, from patient-specific models and preoperative planning to customized medical devices and novel therapeutic approaches. In-stent technology, 3D printing has revolutionized the design and fabrication of intravascular stents, offering tailored solutions for complex anatomies and individualized patient needs. The advantages of 3D-printed stents, such as improved biocompatibility, enhanced mechanical properties, and reduced risk of in-stent restenosis. Moreover, the clinical trials and case studies that shed light on the potential of 3D printing technology to improve patient outcomes and revolutionize the field has been comprehensively discussed. Furthermore, regulatory considerations, and challenges in implementing 3D-printed stents in clinical practice are also addressed, underscoring the need for standardization and quality assurance to ensure patient safety and device reliability. This review highlights a comprehensive resource for clinicians, researchers, and policymakers seeking to harness the full potential of 3D printing technology in the fight against CVD.

Use of customized 3-dimensional printed mandibular prostheses with a dental implant pressure-reducing device in mandibular body defect: A finite element study performing multiresponse surface methodology

Background/purpose

Segmental body defects of the mandible result in the complete loss of the affected region. In our previous study, we investigated the clinical applicability of a customized mandible prosthesis (CMP) with a pressure-reducing device (PRD) in an animal study. In this study, we further incorporated dental implants into the CMP and explored the use of dental implant PRD (iPRD) designs.

Materials and methods

By employing a finite element analysis approach, we created 4 types of CMP: CMP, CMP with iPRD, CMP-PRD, and CMP-PRD with iPRD. We developed 2 parameters for the iPRD: cone length (CL) in the upper part and spring pitch (SP) in the lower part. Using the response surface methodology (RSM), we determined the most suitable structural assignment for the iPRD.

Results

Our results indicate that CMP-PRD had the highest von Mises stress value for the entire assembly (1076.26 MPa). For retentive screws and abutments, CMP with iPRD had the highest von Mises stress value (319.97 and 452.78 MPa, respectively). CMP-PRD had the highest principal stress (131.66 MPa) in the anterior mandible. The iPRD reduced principal stress in both the anterior and posterior mandible. Using the RSM, we generated 25 groups for comparison to achieve the most favorable results for the iPRD and we might suggest the CL to 12 mm and the SP to 0.4 mm in the further clinical trials.

Conclusion

Use of the PRD and iPRD in CMP may resolve the challenges associated with CMP, thereby promoting its usage in clinical practice.

Gene-Activated Materials in Regenerative Dentistry: Narrative Review of Technology and Study Results

Treatment of a wide variety of defects in the oral and maxillofacial regions requires the use of innovative approaches to achieve best outcomes. One of the promising directions is the use of gene-activated materials (GAMs) that represent a combination of tissue engineering and gene therapy. This approach implies that biocompatible materials will be enriched with gene-carrying vectors and implanted into the defect site resulting in transfection of the recipient's cells and secretion of encoded therapeutic protein in situ. GAMs may be presented in various designs depending on the type of material, encoded protein, vector, and way of connecting the vector and the material. Thus, it is possible to choose the most suitable GAM design for the treatment of a particular pathology. The use of plasmids for delivery of therapeutic genes is of particular interest. In the present review, we aimed to delineate the principle of work and various designs of plasmid-based GAMs and to highlight results of experimental and clinical studies devoted to the treatment of periodontitis, jaw bone defects, teeth avulsion, and other pathologies in the oral and maxillofacial regions.

Micro-arc oxidation (MAO) and its potential for improving the performance of titanium implants in biomedical applications

Titanium (Ti) and its alloys have good biocompatibility, mechanical properties and corrosion resistance, making them attractive for biomedical applications. However, their biological inertness and lack of antimicrobial properties may compromise the success of implants. In this review, the potential of micro-arc oxidation (MAO) technology to create bioactive coatings on Ti implants is discussed. The review covers the following aspects: 1) different factors, such as electrolyte, voltage and current, affect the properties of MAO coatings; 2) MAO coatings affect biocompatibility, including cytocompatibility, hemocompatibility, angiogenic activity, corrosion resistance, osteogenic activity and osseointegration; 3) antibacterial properties can be achieved by adding copper (Cu), silver (Ag), zinc (Zn) and other elements to achieve antimicrobial properties; and 4) MAO can be combined with other physical and chemical techniques to enhance the performance of MAO coatings. It is concluded that MAO coatings offer new opportunities for improving the use of Ti and its alloys in biomedical applications, and some suggestions for future research are provided.

The Utility of 3D Printing for Surgical Planning and Patient-Specific Implant Design in Maxillofacial Surgery: A Narrative Review

Maxillofacial reconstructive implants are typically created in standard shapes and have a widespread application in head and neck surgery. During surgical procedures, the implant must be correctly bent according to the architecture of the particular bones. Bending takes practice, especially for untrained surgeons. Furthermore, repeated bending may increase internal stress, resulting in fatigue in vivo under masticatory loading and an array of consequences, including implant failure. There is a risk of fracture, screw loosening, and bone resorption. Resorption, infection, and displacement are usually associated with the use of premade alloplastic implants and autogenous grafts. Recent technological breakthroughs have led to the use of patient-specific implants (PSIs) developed by computer-designed additive manufacturing in reconstructive surgery. The use of computer-designed three-dimensional (3D)-printed PSI allows for more precise restoration of maxillofacial deformities, avoiding the common difficulties associated with premade implants and increasing patient satisfaction. Additive manufacturing is something that refers to a group of additive manufacturing methods. This technique has been quickly used in a variety of surgical procedures. The exponential expansion of this technology can be attributed to its enormous surgical value. Adding 3D printing to a medical practice can be a rewarding experience with stunning results.

3D printing for bone regeneration: challenges and opportunities for achieving predictability

3D printing offers attractive opportunities for large-volume bone regeneration in the oro-dental and craniofacial regions. This is enabled by the development of CAD-CAM technologies that support the design and manufacturing of anatomically accurate meshes and scaffolds. This review describes the main 3D-printing technologies utilized for the fabrication of these patient-matched devices, and reports on their pre-clinical and clinical performance including the occurrence of complications for vertical bone augmentation and craniofacial applications. Furthermore, the regulatory pathway for approval of these devices is discussed, highlighting the main hurdles and obstacles. Finally, the review elaborates on a variety of strategies for increasing bone regeneration capacity and explores the future of 4D bioprinting and biodegradable metal 3D printing.

Severe midface necrosis after liver failure induced fungal infection: A case report on the outcome after reconstruction

INTRODUCTION

Reconstruction of the complex anatomy of the midface is challenging and requires meticulous preparation. Immunosuppression therapy increases patient susceptibility to infection and can compromise wound healing.

PRESENTATION OF CASE

A 22-year-old male presented with acute hepatic failure and underwent liver transplantation. The subsequent immunosuppressing therapy resulted in an invasive fungal infection in the midface involving the left lower eyelid, skin and soft tissue of the cheek and the underlying maxilla and zygoma. After multiple revisions, a primary surgical closure of the defect was performed with a free partial myocutaneous latissimus dorsi flap. 3 years post-transplantation the patient was referred to our hospital with no nasal airflow on the right side and completely obliterated nasal airway on the left side. He experienced trouble with the left eye tearing up and double vision when looking upward. Furthermore, he was troubled by missing 4 teeth in the left upper jaw. Lastly, he was not entirely satisfied with the general cosmetic outcome. These issues were addressed in two stages of surgery while considering that the patient was immunosuppressed.

DISCUSSION

The patient did not suffer any complications or adverse side effects. Overall, the patient was satisfied with the results, and a questionnaire showed a clear improvement in patient reported outcome on both functional and cosmetic results of the problems addressed.

CONCLUSION

Here we present how to plan a complex 3D midface reconstruction on an immunosuppressed patient and a questionnaire follow up on patient reported outcome. The patient reported overall satisfaction.

Extended total temporomandibular joint reconstruction prosthesis: A comprehensive analysis

Alloplastic total temporomandibular joint replacement (TMJR) is the treatment of choice for end-stage temporomandibular joint diseases. Extended TMJR (eTMJR) is a modification of the standard alloplastic fossa-condyle joint that includes components extending further to the skull base or the mandible. The aim of this study is to review the use of the eTMJR prosthesis for the treatment of large craniomaxillofacial defects. Data mining was performed according to the PRISMA statement using online search in databases such as PubMed (Medline), Google Scholar, Dimensions, Semantic Scholar and Web of Science. A total of 19 case reports, 08 case series and 03 retrospective studies were identified. A total of 49 patients were presented in the case reports and case series, who were implanted with 56 eTMJR prostheses (07 bilateral and 42 unilateral procedures). The mean age of the patients was 36.02±16.54 years, the male to female patient ratio was 1:1.72 and the mean follow-up time was 23.74 ± 19.83 months. The eTMJR prosthesis was most frequently used to treat ameloblastoma and hemifacial microsomia. Analysis of the retrospective studies was performed in three domains: the baseline characteristic of patients, treatment outcomes in terms of functional variables and complications after eTMJR prostheses implantation. This study concluded that the implantion of the eTMJR prosthesis was uncommon, that appropriate class of eTMJR prosthesis was not reported, and that the width of the mandibular component (like the length) of eTMJR prosthesis has substantial variations.

3D printing titanium grid scaffold facilitates osteogenesis in mandibular segmental defects

Bone fusion of defect broken ends is the basis of the functional reconstruction of critical maxillofacial segmental bone defects. However, the currently available treatments do not easily achieve this goal. Therefore, this study aimed to fabricate 3D-printing titanium grid scaffolds, which possess sufficient pores and basic biomechanical strength to facilitate osteogenesis in order to accomplish bone fusion in mandibular segmental bone defects. The clinical trial was approved and supervised by the Medical Ethics Committee of the Chinese PLA General Hospital on March 28th, 2019 (Beijing, China. approval No. S2019-065-01), and registered in the clinical trials registry platform (registration number: ChiCTR2300072209). Titanium grid scaffolds were manufactured using selective laser melting and implanted in 20 beagle dogs with mandibular segmental defects. Half of the animals were treated with autologous bone chips and bone substances incorporated into the scaffolds; no additional filling was used for the rest of the animals. After 18 months of observation, radiological scanning and histological analysis in canine models revealed that the pores of regenerated bone were filled with titanium grid scaffolds and bone broken ends were integrated. Furthermore, three patients were treated with similar titanium grid scaffold implants in mandibular segmental defects; no mechanical complications were observed, and similar bone regeneration was observed in the reconstructed patients' mandibles in the clinic. These results demonstrated that 3D-printing titanium grid scaffolds with sufficient pores and basic biomechanical strength could facilitate bone regeneration in large-segment mandibular bone defects.

A Novel Method to Reconstruct the Upper and Lower Jaws Using 3D-Custom-Made Titanium Implants

BACKGROUND

This paper presents a novel method of upper and lower jaw reconstruction using 3D-custom-made titanium implants with abutment-like projections. The implants were designed to rehabilitate the oral and facial shape, esthetic, function, and occlusion.

PATIENT AND METHOD

A 20-year-old boy was diagnosed as having Gorlin syndrome. The patient suffered from having large bony defects, after ablative multiple keratocysts resection, of the maxilla and mandible. The resulting defects were reconstructed with 3D-custom-made titanium implants. The implants with abutment-like projections were simulated, printed, and fabricated with a selective milling method based on computed tomography scan data.

RESULT

There were no postoperative infections or foreign body reactions during the 1-year follow-up period.

CONCLUSION

To the best of our knowledge, this is the first report on the use of 3D-custom-made titanium implants with abutment-like projections, attempting to rehabilitate the occlusion and overcome the limitations of custom-made implants in treating large bony defects of the maxilla and mandible.

Morphometric analysis of the infratemporal fossa using three-dimensional (3D) digital models

PURPOSE

The infratemporal fossa contains important neurovascular components and is directly related to other anatomical regions and structures. The morphometric distances between the bones forming its borders have not been thoroughly investigated. The aim of this study was to determine the morphometry of the infratemporal fossa.

METHODS

3D models of the skull of 83 individuals were reconstructed from DICOM datasets, from which length, depth and width measurements were determined and compared between genders and the right and left sides.

RESULTS

All measurements obtained were significantly different between males and females. There were also significant differences between the left and right sides for depth and width measurements.

CONCLUSION

This is the first study to determine and investigate measurements of the infratemporal fossa; as such it provides a comprehensive view of the morphology of the fossa. It provides valuable information for surgical interventions and differential diagnoses of pathologies in this region, as well as enhancing its understanding in medical education.

Patient Specific Alloplastic Implant Reconstruction of Mandibular Defects-Safe Practice Recommendations and Guidelines

Mandibular continuity defects are commonly seen after tumor resection, osteomyelitis or maxillofacial trauma. Three-dimensional reconstruction of these mandibular segmental defects is critical for proper mandibular functioning and esthetics. Various methods used to reconstruct such defects include bridging reconstruction plates, modular endoprosthesis, non-vascularized and vascularized bone grafting with stock reconstruction plate or patient specific implants (PSI) and tissue engineering bone transfer. But in the recent years, literature documents use of PSI only alloplastic reconstruction as an alternate to microvascular bone flap reconstruction. Representative cases enumerate current practice of 'patient specific implant only' mandibular reconstruction and its pitfalls. This article discusses current status of literature on PSI's, choice of indications for 'PSI only' mandibular reconstruction and also proposes guidelines for safe practice of patient specific implant reconstruction of mandible.

An innovative additively manufactured implant for mandibular injuries: Design and preparation processes based on simulation model

Objective: For mandibular injury, how to utilize 3D implants with novel structures to promote the reconstruction of large mandibular bone defect is the major focus of clinical and basic research. This study proposed a novel 3D titanium lattice-like implant for mandibular injuries based on simulation model, which is designed and optimized by a biomechanical/mechanobiological approach, and the working framework for optimal design and preparation processes of the implant has been validated to tailored to specific patient biomechanical, physiological and clinical requirements. Methods: This objective has been achieved by matching and assembling different morphologies of a lattice-like implant mimicking cancellous and cortical bone morphologies and properties, namely, an internal spongy trabecular-like structure that can be filled with bone graft materials and an external grid-like structure that can ensure the mechanical bearing capacity. Finite element analysis has been applied to evaluate the stress/strain distribution of the implant and bone graft materials under physiological loading conditions to determine whether and where the implant needs to be optimized. A topological optimization approach was employed to improve biomechanical and mechanobiological properties by adjusting the overall/local structural design of the implant. Results: The computational results demonstrated that, on average, values of the maximum von-Mises stress in the implant model nodes could be decreased by 43.14% and that the percentage of optimal physiological strains in the bone graft materials can be increased from 35.79 to 93.36% since early regeneration stages. Metal additive manufacturing technology was adopted to prepare the 3D lattice-like implant to verify its feasibility for fabrication. Following the working framework proposed in this study, the well-designed customized implants have both excellent biomechanical and mechanobiological properties, avoiding mechanical failure and providing sufficient biomechanical stimuli to promote new bone regeneration. Conclusion: This study is expected to provide a scientific and feasible clinical strategy for repairing large injuries of mandibular bone defects by offering new insights into design criteria for regenerative implants.