Personalized lattice-structured prosthesis as a graftless solution for mandible reconstruction and prosthetic restoration: A finite element analysis.

Oral cavity tumors are a prevalent cause of mandible reconstruction surgeries. The mandible is vital for functions like oralization, respiration, mastication, and deglutition. Current mandible reconstruction methods have low success rates due to complications like plate fracture or exposure, infections, and screw loosening. Autogenous bone grafts are commonly used but carry the risk of donor region morbidity. Despite technological advances, an ideal solution for mandible reconstruction remains elusive. Additive manufacturing in medicine offers personalized prosthetics from patient-specific medical images, allowing for the creation of porous structures with tailored mechanical properties that mimic bone properties. This study compared a commercial reconstruction plate with a lattice-structured personalized prosthesis under different biting and osseointegration conditions using Finite Element Analysis. Patient-specific images were obtained from an individual who underwent mandible reconstruction with a commercial plate and suffered from plate fracture by fatigue after 26 months. Compared to the commercial plate, the maximum von Mises equivalent stress was significantly lowered for the personalized prosthesis, hindering a possible fatigue fracture. The equivalent von Mises strains found in bone were within bone maintenance and remodeling intervals. This work introduces a design that doesn't require grafts for large bone defects and allows for dental prosthesis addition without the need for implants.

Cranial reconstruction: 3D biomodel and custom-built implant created using additive manufacturing.

Additive manufacturing (AM) technology from engineering has helped to achieve several advances in the medical field, particularly as far as fabrication of implants is concerned. The use of AM has made it possible to carry out surgical planning and simulation using a three-dimensional physical model which accurately represents the patient's anatomy. AM technology enables the production of models and implants directly from a 3D virtual model, facilitating surgical procedures and reducing risks. Furthermore, AM has been used to produce implants designed for individual patients in areas of medicine such as craniomaxillofacial surgery, with optimal size, shape and mechanical properties. This work presents AM technologies which were applied to design and fabricate a biomodel and customized implant for the surgical reconstruction of a large cranial defect. A series of computed tomography data was obtained and software was used to extract the cranial geometry. The protocol presented was used to create an anatomic biomodel of the bone defect for surgical planning and, finally, the design and manufacture of the patient-specific implant.

Paired evaluation of calvarial reconstruction with prototyped titanium implants with and without ceramic coating.

PURPOSE: To investigate the osseointegration properties of prototyped implants with tridimensionally interconnected pores made of the Ti6Al4V alloy and the influence of a thin calcium phosphate coating. METHODS: Bilateral critical size calvarial defects were created in thirty Wistar rats and filled with coated and uncoated implants in a randomized fashion. The animals were kept for 15, 45 and 90 days. Implant mechanical integration was evaluated with a push-out test. Bone-implant interface was analyzed using scanning electron microscopy. RESULTS: The maximum force to produce initial displacement of the implants increased during the study period, reaching values around 100N for both types of implants. Intimate contact between bone and implant was present, with progressive bone growth into the pores. No significant differences were seen between coated and uncoated implants. CONCLUSION: Adequate osseointegration can be achieved in calvarial reconstructions using prototyped Ti6Al4V Implants with the described characteristics of surface and porosity.

Paired evaluation of calvarial reconstruction with prototyped titanium implants with and without ceramic coating

PURPOSE: To investigate the osseointegration properties of prototyped implants with tridimensionally interconnected pores made of the Ti6Al4V alloy and the influence of a thin calcium phosphate coating. METHODS: Bilateral critical size calvarial defects were created in thirty Wistar rats and filled with coated and uncoated implants in a randomized fashion. The animals were kept for 15, 45 and 90 days. Implant mechanical integration was evaluated with a push-out test. Bone-implant interface was analyzed using scanning electron microscopy. RESULTS: The maximum force to produce initial displacement of the implants increased during the study period, reaching values around 100N for both types of implants. Intimate contact between bone and implant was present, with progressive bone growth into the pores. No significant differences were seen between coated and uncoated implants. CONCLUSION: Adequate osseointegration can be achieved in calvarial reconstructions using prototyped Ti6Al4V Implants with the described characteristics of surface and porosity. .

Thermal, morphologic and mechanical characterization of poly (L-lactic acid)/poly (hydroxybutyrate-cohydroxyvalerate) blends

O desenvolvimento de polímeros bioabsorvíveis pode ser considerado como um avanço no desenvolvimento de materiais biomédicos. Materiais bioabsorvíveis apresentam numerosas aplicações na Medicina. A proposta deste trabalho foi estudar blendas de Poli(L-ácido láctico) e Poli(3-hidroxibutirato-co-3-hidroxivalerato) PLLA/PHBV em diferentes composições (100/0, 60/40, 50/50, 40/60, e 0/100), obtidas através da fusão dos polímeros em uma mini injetora Mini Max Molder, obtendo pinos de 31x90 mm. As blendas foram caracterizadas através das análises de Calorimetria Diferencial de Varredura(DSC), Análise Dinâmico-Mecânica(DMA), Microscopia Eletrônica de Varredura(SEM) e ensaios mecânicos. As análises de DSC e DMA mostraram que as blendas de PLLA/PHBV apresentaram duas temperaturas de transição vítrea, cristalização e fusão distintas, respectivas aos polímeros puros, indicando a imiscibilidade das blendas em todas as composições. Através do SEM foi possível observar que tanto os polímeros puros como as blendas apresentaram uma morfologia densa, sendo que nas blendas verificou-se a presença de duas fases, confirmando os dados de DSC e DMA. Os testes de ensaio mecânico de flexão mostraram que o PLLA impõe maior resistência mecânica e flexibilidade ao sistema. Devido à sua boa compatibilização térmica e mecânica, as blendas de PLLA/PHBV, mostraram ser uma boa alternativa para aplicação na área ortopédica