In Silico Mechanical Effort Analysis of the All-On-4 Design Performed With Platform-Switching Distal Short Dental Implants.

Short dental implants with platform matching connection have been used for the rehabilitation of atrophic jaws whenever standard-length dental implants cannot be placed without prior bone augmentation. Yet, there remains a lack of data regarding the risk of technical failures when the all-on-4 configuration is performed in atrophic jaws with platform-switching distal short dental implants. Thus, the current study used the finite element method to evaluate the mechanical behavior at the level of the prosthetic components of the all-on-4 concept performed in atrophic mandible using short-length distal implants with platform switching (PSW) connection. Three models of the all-on-4 configuration were generated in human atrophic mandibles. The geometric models consisted of PSW connection tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) and straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants. A resultant force of 300 N was performed obliquely in the left side and posterior region of the prosthetic bar. The von Mises equivalent stress (σvm) and maximum and minimum principal stresses (σmax and σmin) were performed at level of the prosthetic components/implants and peri-implant bone crest, respectively. The general displacement of the models was also evaluated. The stress analysis was performed on the side of load application. The AO4S configuration showed the lowest values of σvm in the mesial left (ML) and distal left (DL) abutments (37.53 MPa and 232.77 MPa, respectively) and dental implants (91.53 MPa and 231.21 MPa, respectively). The AO4Sh configuration showed the highest values of σvm in the bar screw (102.36 MPa), abutment (117.56 MPa), and dental implant (293.73 MPa) of the ML area. Among the models, the highest values of σmax and σmin were noticed in the peri-implant bone crest of the AO4T design (131.48 MPa and 195.31 MPa, respectively). All models showed similar values of general displacements, which were concentrated in the mandible symphysis. The all-on-4 configurations designed with PSW connection and tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) or straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants were not associated with higher odds of technical failures. The AO4Sh design may be a promising option for the prosthetic rehabilitation of atrophic jaws.

Antineoplastic agents aggravate the damages caused by nicotine on the peri-implant bone: an in vivo histomorphometric and immunohistochemical study in rats.

OBJECTIVE: To assess the interaction between chemotherapy and normal tissues is critical to assure quality of life during and after the treatment of cancer. This study evaluated the influence of cisplatin (CIS) and 5-fluorouracil (5-FU) over the peri-implant tissues around osseointegrated titanium implants in animals previously exposed to nicotine. Materials and methods One hundred twenty male rats were divided into two groups, receiving via subcutaneous injection, either physiological saline solution (PSS) (n = 30) or nicotine hemissulfate (NIC) (n = 90) for 30 days prior to implants' placement. One titanium implant (4.0 × 2.2 mm) was installed in each tibia of all animals. PSS and NIC were continued for 30 days after surgery. Five days after cessation, rats were subdivided into three subgroups in accordance with systemic treatments with either PSS, CIS, or 5-FU. Euthanasia was performed at 50, 65, and 95 days post-surgery. Histometric, histopathological, and immunohistochemical analyses were performed. RESULTS: NIC-CIS and NIC-5FU presented lower BIC (50, 65, and 95 days) and bone area fraction occupancy (BAFO) (65 and 95 days) than group NIC. Intense inflammatory infiltration, severe tissue breakdown, reduced expression of bone formation biomarkers, and upregulation of TRAP were observed in NIC-CIS and NIC-5FU when compared with group NIC. TRAP expression was significantly higher in NIC-5FU as compared with NIC-CIS at 50 and 95 days. Groups NIC, NIC-CIS, and NIC-5FU presented statistically significant negative impact in all outcome parameters than group PSS. CONCLUSION: CIS and 5-FU severely disrupted the peri-implant tissues around osseointegrated implants in animals previously exposed to nicotine. CLINICAL RELEVANCE: Assessing the interaction between chemotherapy and normal tissues is critical to assure quality of life during and after the cancer treatment.

Dose-dependent effects of zoledronic acid on the osteogenic differentiation of human bone marrow stem cells (hBMSCs).

Recent studies have shown that bisphosphonates can also impact osteoblasts besides osteoclasts. This study aimed to evaluate the effects of different concentrations of Zoledronic acid (ZA) during the osteogenic differentiation of human Bone Marrow Stem Cells (hBMSCs) in vitro. Thus, osteogenic differentiation of hBMSCs was conducted with different concentrations of Zoledronic Acid (ZA) (0, 0.1, 1.0, and 5.0 µM) for the first 3 days. Cell metabolism was quantified at 1-, 3-, 7-, and 14 days. At 7- and 14-days, the following analyses were performed: 1) mineralization nodule assay, 2) LIVE/DEAD™, 3) cell adhesion and spreading, 4) alkaline phosphatase (ALP) activity, and 5) qPCR analysis for RUNX-2), ALPL, and COL1 A1. Data were analyzed by ANOVA 2-way, followed by Tukey's post hoc test (p < 0.05). Cell metabolism (3-, 7-, and 14-days) (p < 0.001), mineralization (7-, 14-days) (p < 0.001), and ALP activity (14-days) (p < 0.001) were reduced in ZA 5.0 µM when compared to control (no ZA). Also, ZA 5.0 µM downregulated the expression of RUNX2 at 7- and 14-days (p < 0.001). It is possible to conclude that ZA (5.0 µM) can impair hBMSC differentiation into osteoblasts and interferes with its mineralization phase.

Temporomandibular Joint Fibrocartilage Contains CD105 Positive Mouse Mesenchymal Stem/Progenitor Cells with Increased Chondrogenic Potential.

Objective: A specific type of mesenchymal stem/progenitor cells (MSPCs), CD105+ is reported to aid in cartilage regeneration through TGF-ß/Smad2-signalling. The purpose of this study was to identify and characterize CD105+ MSPCs in temporomandibular joint (TMJ) cartilage. Materials and Methods: MSPCs were isolated from mouse TMJ condyle explants and evaluated for their clonogenicity and pluripotential abilities. MSPC were examined for CD105 antigen using immunohistochemistry and flow cytometry. Results: Immunohistochemistry revealed presence of CD105+ MSPCs in the proliferative zone of condyle's cartilage. Only 0.2% of isolated MSPCs exhibited CD105, along with the stem cell surface markers CD44 and Sca-1. In CD105+ MSPCs, intracellular immunostaining revealed significantly higher (p < 0.05) protein levels of collagen type 1, 2, proteoglycan 4. Ability for chondrogenic differentiation was found to be significantly higher (p < 0.05) after 4 weeks compared to CD105- cells, using alcian blue staining. CD105+ cells were found to resemble an early MSPC subgroup with significantly higher gene expression of biglycan, proteoglycan 4, collagen type 2, Gli2, Sox5 (p < 0.001) and Sox9 (p < 0.05). In contrast, significantly lower levels of Runx2 (p < 0.05), Osterix, Trps1, Col10a1 (p < 0.01), Ihh (p < 0.001) related to chondrocyte senescence and commitment to osteogenic lineage, were observed compared to CD105- cells. Conclusion: The study showed the existence of a CD105+ MSPC subgroup within TMJ fibrocartilage that may be activated to aid in fibrocartilage repair.

Evaluation of oral implant survival rate in postmenopausal women with osteopenia/osteoporosis. A retrospective pilot study.

BACKGROUND: Implant placement is a common part of dental rehabilitation in older individuals. The role of diminished bone mineral density on the healing of dental implants remains to be elucidated. OBJECTIVE: The aim of this study was to assess the implant survival rate in postmenopausal women with osteopenia/osteoporosis. METHODS: A retrospective cohort study was conducted of postmenopausal women treated with dental implants and stratified into two groups: those receiving antiresorptive therapy (W ≥ 50 years S) or those not receiving treatment (W ≥ 50 years U). The predictor variable was osteopenia/osteoporosis treatment. The outcome variable was implant failure rate at stage two uncovering. Other study variables included: age, implant location, and bone graft placement. T-test, chi-square test, and univariate and multivariate logistic regression were computed. A p-value<0.05 was considered statistically significant. RESULTS: The sample was composed of 93 W ≥ 50 years U (197 implants) and 114 W ≥ 50 years S (189 implants). W ≥ 50 years U showed a statistically higher implant failure rate with chi-square testing compared to W ≥ 50 years S (p=0.022). However, univariate, and multivariate logistic regression between age, location, bone grafting, and implant failure did not demonstrate significant associations. CONCLUSION: Both groups integrated dental implants successfully, with a low failure rate. Implant location, bone grafting, and osteopenia/osteoporosis treatment did not significantly affect osseointegration at uncovering.

A new multiphase calcium phosphate graft material improves bone healing-An in vitro and in vivo analysis.

This study aims to evaluate the potential of a novel biomaterial synthesized from amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), and hydroxyapatite (HA) to repair critical-sized defects (CSD) in rabbit calvaria. In vitro analyses of cell viability, cell proliferation, formation of mineral nodules, and cell differentiation using qPCR were performed for comparing experimental calcium phosphate (ECP), deproteinized bovine bone (DBB), and beta-tricalcium phosphate (ß-TCP). Bilateral CSDs were created in 45 rabbit calvaria. Six groups were evaluated: ECP, ECP + fibrin sealant (ECP + S), coagulum, autogenous bone, DBB, and ß-TCP. Euthanasia was performed at 2, 4, and 8 weeks, followed by micro-computed tomography and histological and immunohistochemical analyses. Results from in vitro analyses revealed similar biocompatibility for all tested materials and a tendency for higher gene expression of some bone markers in the ECP group than in ß-TCP and DBB groups at 7 days. In contrast to that in DBB and ß-TCP groups, ECP displayed growing bone volume over total volume percentage (BV/TV%) with time in vivo. Histological analysis revealed a greater number of giant cells and reduced size of grafted particles in ECP during all periods of analysis. RUNX-2 expression was statistically lower in ECP than DBB at 2 and 4 weeks. Despite no statistical significance, ECP presented the highest absolute values for ALP-expression at 2, 4, and 8 weeks compared with other groups. Together, our findings indicate that a combination of the ACP, OCP, and HA phases into ECP is beneficial and promising for bone regeneration.

Perspectivas atuais da engenharia de tecidos da articulação temporomandibular / Perspectivas Actuales de la Ingeniería de Tejidos para la Articulación Temporomandibular / Current Perspectives of Tissue Engineering for the Temporomandibular Joint

Introdução: As limitações das terapias atuais para doenças degenerativas da articulação temporomandibular (ATM) levaram ao aumento do interesse em estratégias regenerativas. A engenharia de tecidos (ET), combinando células-tronco, arcabouços e fatores de crescimento, pode fornecer uma substituição biológica funcional e permanente das estruturas da ATM, além de prevenir o avanço de doenças degenerativas. Objetivo: Este artigo descreve as perspectivas atuais da ET das estruturas da ATM em modelos animais. Metodologia: As abordagens da ET foram categorizadas de acordo com as estruturas primárias da ATM: 1) o disco articular, 2) o côndilo mandibular e 3) a fossa glenóide e eminência articular. Resultados: As áreas com a maior quantidade de estudos são o côndilo mandibular e disco articular, em estudos que abordam o uso de arcabouços tridimensionais, de origem sintética e/ou natural, podendo ou não estar associados a células tronco (diferenciadas ou não) e a fatores de crescimento. Conclusão: A ET da ATM ainda é uma área relativamente nova, em desenvolvimento e em constante avanço. Os avanços tecnológicos desenvolvidos nessa área têm o potencial de auxiliar no desenvolvimento de terapias mais eficientes e menos invasivos... (AU)

Introducción: Las limitaciones de las terapias actuales para las enfermedades degenerativas de la articulación temporomandibular (ATM) han llevado a un mayor interés en las estrategias regenerativas. La ingeniería de tejidos, que combina células, andamios y factores de crecimiento, puede proporcionar un reemplazo biológico funcional y permanente de las estructuras de la ATM, además de prevenir el avance de enfermedades degenerativas. Objetivo: Este artículo describe las perspectivas actuales de la ingeniería de tecidos de las estructuras de la ATM en modelos animales. Metodología: Los enfoques de ingeniería de tejidos se clasificaron según las estructuras primarias de la ATM: 1) el disco articular, 2) el cóndilo mandibular y 3) la fosa glenoidea y la eminencia articular. Resultados: Las áreas con mayor número de estudios son el cóndilo mandibular y el disco articular, en estudios que abordan el uso de estructuras tridimensionales, de origen sintético y/o natural, que pueden o no estar asociadas a células (diferenciadas o no) y con factores de crecimiento. Conclusión: La ingeniería de tejidos de la ATM es todavía un área relativamente nueva, en desarrollo y en constante avance. Los avances tecnológicos desarrollados en esta área tienen el potencial de ayudar en el desarrollo de terapias más eficientes y menos invasivas... (AU)

Introduction: The limitations of current therapies for degenerative diseases of the temporomandibular joint (TMJ) have led to increased interest in regenerative strategies. Tissue engineering (TE), combining stem cells, scaffolds, and growth factors, can provide a functional and permanent biological replacement of TMJ structures, in addition to preventing the advancement of degenerative diseases. Aim: This article describes current TE perspectives of TMJ structures in animal models. Methods: TE approaches were categorized according to the primary TMJ structures: 1) the articular disc, 2) the mandibular condyle, and 3) the glenoid fossa and articular eminence. Results: The areas with the greatest number of studies are the mandibular condyle and articular disc, in studies that address the use of three-dimensional scaffolds, of synthetic and/ or natural origin, which may or may not be associated with stem cells (differentiated or not) and with growth factors. Conclusion: TE of the TMJ is still a relatively new, developing, and constantly advancing area. The technological advances developed in this area have the potential to assist in the development of more efficient and less invasive therapies... (AU)

Perspectivas atuais da Engenharia de Tecidos da articulação temporomandibular / Perspectivas Actuales de la Ingeniería de Tejidos para la Articulación Temporomandibular / Current Perspectives of Tissue Engineering for the Temporomandibular Joint

Introdução: As limitações das terapias atuais para doenças degenerativas da articulação temporomandibular (ATM) levaram ao aumento do interesse em estratégias regenerativas. A engenharia de tecidos (ET), combinando células-tronco, arcabouços e fatores de crescimento, pode fornecer uma substituição biológica funcional e permanente das estruturas da ATM, além de prevenir o avanço de doenças degenerativas. Objetivo: Este artigo descreve as perspectivas atuais da ET das estruturas da ATM em modelos animais. Metodologia: As abordagens da ET foram categorizadas de acordo com as estruturas primárias da ATM: 1) o disco articular, 2) o côndilo mandibular e 3) a fossa glenóide e eminência articular. Resultados: As áreas com a maior quantidade de estudos são o côndilo mandibular e disco articular, em estudos que abordam o uso de arcabouços tridimensionais, de origem sintética e/ou natural, podendo ou não estar associados a células tronco (diferenciadas ou não) e a fatores de crescimento. Conclusão: A ET da ATM ainda é uma área relativamente nova, em desenvolvimento e em constante avanço. Os avanços tecnológicos desenvolvidos nessa área têm o potencial de auxiliar no desenvolvimento de terapias mais eficientes e menos invasivos... (AU)

Introducción: Las limitaciones de las terapias actuales para las enfermedades degenerativas de la articulación temporomandibular (ATM) han llevado a un mayor interés en las estrategias regenerativas. La ingeniería de tejidos, que combina células, andamios y factores de crecimiento, puede proporcionar un reemplazo biológico funcional y permanente de las estructuras de la ATM, además de prevenir el avance de enfermedades degenerativas. Objetivo: Este artículo describe las perspectivas actuales de la ingeniería de tecidos de las estructuras de la ATM en modelos animales. Metodología: Los enfoques de ingeniería de tejidos se clasificaron según las estructuras primarias de la ATM: 1) el disco articular, 2) el cóndilo mandibular y 3) la fosa glenoidea y la eminencia articular. Resultados: Las áreas con mayor número de estudios son el cóndilo mandibular y el disco articular, en estudios que abordan el uso de estructuras tridimensionales, de origen sintético y/o natural, que pueden o no estar asociadas a células (diferenciadas o no) y con factores de crecimiento. Conclusión: La ingeniería de tejidos de la ATM es todavía un área relativamente nueva, en desarrollo y em constante avance. Los avances tecnológicos desarrollados en esta área tienen el potencial de ayudar en el desarrollo de terapias más eficientes y menos invasivas... (AU)

Introduction: The limitations of current therapies for degenerative diseases of the temporomandibular joint (TMJ) have led to increased interest in regenerative strategies. Tissue engineering (TE), combining stem cells, scaffolds, and growth factors, can provide a functional and permanent biological replacement of TMJ structures, in addition to preventing the advancement of degenerative diseases. Aim: This article describes current TE perspectives of TMJ structures in animal models. Methods: TE approaches were categorized according to the primary TMJ structures: 1) the articular disc, 2) the mandibular condyle, and 3) the glenoid fossa and articular eminence. Results: The areas with the greatest number of studies are the mandibular condyle and articular disc, in studies that address the use of three-dimensional scaffolds, of synthetic and/or natural origin, which may or may not be associated with stem cells (differentiated or not) and with growth factors. Conclusion: TE of the TMJ is still a relatively new, developing, and constantly advancing area. The technological advances developed in this area have the potential to assist in the development of more efficient and less invasive therapies... (AU)

Surface physical chemistry properties in coated bacterial cellulose membranes with calcium phosphate.

Bacterial cellulose has become established as a new biomaterial, and it can be used for medical applications. In addition, it has called attention due to the increasing interest in tissue engineering materials for wound care. In this work, the bacterial cellulose fermentation process was modified by the addition of chondroitin sulfate to the culture medium before the inoculation of the bacteria. The biomimetic process with heterogeneous calcium phosphate precipitation of biological interest was studied for the guided regeneration purposes on bacterial cellulose. FTIR results showed the incorporation of the chondroitin sulfate in the bacterial cellulose, SEM images confirmed the deposition of the calcium phosphate on the bacterial cellulose surface, XPS analysis showed a selective chemical group influences which change calcium phosphate deposition, besides, the calcium phosphate phase with different Ca/P ratios on bacterial cellulose surface influences wettability. XTT results concluded that these materials did not affect significantly in the cell viability, being non-cytotoxic. Thus, it was produced one biomaterial with the surface charge changes for calcium phosphate deposition, besides different wettability which builds new membranes for Guided Tissue Regeneration.

Caracterização físico-química, morfológica, análise mecânica e de elementos finitos 3D, de diferentes placas e parafusos metálicos e técnicas de fixação interna, empregadas em fraturas de ângulo mandibular / Physico-chemical and morphological characterization, mechanical and 3D finite element analysis, of different metal plates and screws and internal fixation techniques, employed in mandibular angle fractures

Proposição: Realizar uma caracterização físico-química, morfológica e comparar o comportamento mecânico de uma liga experimental de Ti-Mo, ao sistema de fixação análogo à base de Ti, em fraturas de ângulo mandibular, favoráveis ao deslocamento. Adicionalmente, análises de elementos finitos 3D foram realizadas para avaliar o padrão de distribuição de tensões nas placas e nos parafusos. Material e Método: Vinte e oito réplicas de mandίbulas de poliuretano foram usadas e uniformemente seccionadas na região do ângulo mandibular esquerdo. Estas foram divididas em 4 grupos considerando o material das placas e as técnicas de fixação interna: grupo Eng 1P, uma placa (zona de tensão da mandίbula) e 4 parafusos de 6 mm de comprimento; grupo Eng 2P, duas placas (uma na zona de tensão da mandίbula e a outra na zona de compressão), a primeira fixada com 4 parafusos de 6 mm de comprimento e a segunda com 4 parafusos de 12 mm de comprimento, sendo todo o material de fixação do sistema 2.0-mm. Os mesmos grupos foram criados para a liga Ti-15Mo. Cada grupo foi submetido a uma carga vertical linear no primeiro molar. As médias e os desvios-padrão foram comparados para avaliação estatίstica (ANOVA; p < .05). Adicionalmente, foi construído um modelo de elementos finitos 3D considerando as mesmas variáveis para avaliar as tensões equivalentes de von Mises (σvM) nas placas e nos parafusos. Resultados: Diferença estatisticamente significativa (p < .05) foi encontrada quando foi realizada a comparação entre ambas as técnicas de fixação (1 e 2 placas), independentemente do material das placas (cpTi and Ti-15Mo). Quando considerado os valores das tensões equivalentes de von Mises (σvM) para a comparação entre ambos os grupos (Eng and Ti-15Mo) com 1 placa, verificou-se uma redução de 10.5% na placa e de 29.0% nos parafusos, para o grupo da liga titânio-molibdênio. Ainda, quando foi realizada a comparação dos mesmos grupos com 2 placas, o fator mais relevante foi uma redução, na...

Purpose: Perform a physico-chemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures, favorable to displacement. Additionally, finite element analysis was performed to assess the stress distribution in the plates and screws. Material and Method: Twenty eight polyurethane mandible replicas were used and uniformly sectioned on the left mandibular angle. These were divided into 4 groups considering the material of the plates and the internal fixation techniques: group Eng 1P, one 2.0-mm plate (tension zone of the mandible) and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates (one in the tension zone of the mandible and the other in the compression zone), the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the titanium alloy (Ti-15Mo). Each group was subjected to linear vertical loading at the first molar. Means and standard deviations were compared with respect to statistical significance (ANOVA; p < .05). Additionally, an three-dimensional finite element model reproducing the characteristics of the specimens used in the mechanical tests were created to evaluate the von Mises equivalent stress (σvM) in the plates and screws. Results: Statistically significant difference (p < .05) was found when the comparison between both internal fixation techniques (1 and 2 plates) was performed, regardless the materials of the plates (cpTi and Ti-15Mo). When considering the von Mises equivalent stress (σvM) values for the comparison between both groups (Eng and Ti-15Mo) with 1 plate, an decrease of 10.5% in the plate and an decrease of 29.0% in the screws for the titanium-molybdenum- based group was observed. Also, when comparing the same groups with 2 plates, the relevant fact was an decrease of 28.5% in the screws for the Ti- 15Mo group. Conclusion: The 2P technique showed…

Caracterização físico-química, morfológica, análise mecânica e de elementos finitos 3D, de diferentes placas e parafusos metálicos e técnicas de fixação interna, empregadas em fraturas de ângulo mandibular / Physico-chemical and morphological characterization, mechanical and 3D finite element analysis, of different metal plates and screws and internal fixation techniques, employed in mandibular angle fractures

Proposição: Realizar uma caracterização físico-química, morfológica e comparar o comportamento mecânico de uma liga experimental de Ti-Mo, ao sistema de fixação análogo à base de Ti, em fraturas de ângulo mandibular, favoráveis ao deslocamento. Adicionalmente, análises de elementos finitos 3D foram realizadas para avaliar o padrão de distribuição de tensões nas placas e nos parafusos. Material e Método: Vinte e oito réplicas de mandίbulas de poliuretano foram usadas e uniformemente seccionadas na região do ângulo mandibular esquerdo. Estas foram divididas em 4 grupos considerando o material das placas e as técnicas de fixação interna: grupo Eng 1P, uma placa (zona de tensão da mandίbula) e 4 parafusos de 6 mm de comprimento; grupo Eng 2P, duas placas (uma na zona de tensão da mandίbula e a outra na zona de compressão), a primeira fixada com 4 parafusos de 6 mm de comprimento e a segunda com 4 parafusos de 12 mm de comprimento, sendo todo o material de fixação do sistema 2.0-mm. Os mesmos grupos foram criados para a liga Ti-15Mo. Cada grupo foi submetido a uma carga vertical linear no primeiro molar. As médias e os desvios-padrão foram comparados para avaliação estatίstica (ANOVA; p < .05). Adicionalmente, foi construído um modelo de elementos finitos 3D considerando as mesmas variáveis para avaliar as tensões equivalentes de von Mises (σvM) nas placas e nos parafusos. Resultados: Diferença estatisticamente significativa (p < .05) foi encontrada quando foi realizada a comparação entre ambas as técnicas de fixação (1 e 2 placas), independentemente do material das placas (cpTi and Ti-15Mo). Quando considerado os valores das tensões equivalentes de von Mises (σvM) para a comparação entre ambos os grupos (Eng and Ti-15Mo) com 1 placa, verificou-se uma redução de 10.5% na placa e de 29.0% nos parafusos, para o grupo da liga titânio-molibdênio. Ainda, quando foi realizada a comparação dos mesmos grupos com 2 placas, o fator mais relevante foi uma redução, na...

Purpose: Perform a physico-chemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures, favorable to displacement. Additionally, finite element analysis was performed to assess the stress distribution in the plates and screws. Material and Method: Twenty eight polyurethane mandible replicas were used and uniformly sectioned on the left mandibular angle. These were divided into 4 groups considering the material of the plates and the internal fixation techniques: group Eng 1P, one 2.0-mm plate (tension zone of the mandible) and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates (one in the tension zone of the mandible and the other in the compression zone), the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the titanium alloy (Ti-15Mo). Each group was subjected to linear vertical loading at the first molar. Means and standard deviations were compared with respect to statistical significance (ANOVA; p < .05). Additionally, an three-dimensional finite element model reproducing the characteristics of the specimens used in the mechanical tests were created to evaluate the von Mises equivalent stress (σvM) in the plates and screws. Results: Statistically significant difference (p < .05) was found when the comparison between both internal fixation techniques (1 and 2 plates) was performed, regardless the materials of the plates (cpTi and Ti-15Mo). When considering the von Mises equivalent stress (σvM) values for the comparison between both groups (Eng and Ti-15Mo) with 1 plate, an decrease of 10.5% in the plate and an decrease of 29.0% in the screws for the titanium-molybdenum- based group was observed. Also, when comparing the same groups with 2 plates, the relevant fact was an decrease of 28.5% in the screws for the Ti- 15Mo group. Conclusion: The 2P technique showed…

Uso da proteína morfogenética óssea recombinante humana-2 em levantamento de assoalho de seio maxilar / Recombinant human bone morphogenetic protein-2 in maxillary sinus floor augmentation

Pacientes desdentados posteriores frequentemente apresentam pneumatização dos seios maxilares, dificultando a colocação de implantes dentários. Atualmente, o material mais utilizado para o preenchimento de seio maxilar é o enxerto ósseo autógeno retirado de sítios intra ou extrabucais. Apesar desse procedimento ter sua eficácia comprovada clínica e histologicamente, nem sempre é bem tolerado pelos pacientes devido à morbidade associada à manipulação da área doadora. Por isso, vários substitutos ósseos vêm sendo desenvolvidos. A proteína óssea morfogenética recombinante humana-2 surgiu recentemente como uma alternativa aos enxertos autógenos, oferecendo excelente padrão de reparo e/ou neoformação óssea, quando utilizada na reconstrução de rebordos alveolares, possibilitando a reabilitação com próteses implantossuportadas. Nesse trabalho foi feita uma revisão da literatura e apresentação de caso de levantamento de assoalho de seio maxilar bilateral com o uso da proteína óssea morfogenética.

Edentulous patients in the posterior maxillary region frequently present pneumatization of maxillary sinuses, which makes difficult installation of dental implants. Nowadays, most commonly used materials for maxillary sinus filling are autogenous bone grafts from intra- or extra-oral donor sites. Despite the elevated clinical and histologic success rates of this procedure, it is always not well-tolerated by patients due to morbidity seen after donor site manipulation. For this, many bone substitutes have been developed. Recombinant human bone morphogenetic protein-2 appeared recently as an alternative to autogenous bone grafts, offering excellent patterns of bone repair and/or neoformation when used for reconstruction of alveolar ridges, allowing rehabilitation with implant-supported prostheses. The aim of this article is to perform a literature review and also to report a case in which bilateral elevation of maxillary sinus floor was performed along with rhBMP-2.

Uso da proteína morfogenética óssea recombinante humana-2 em levantamento de assoalho de seio maxilar / Recombinant human bone morphogenetic protein-2 in maxillary sinus floor augmentation

Pacientes desdentados posteriores freqüentemente apresentam pneumatização dos seios maxilares, dificultando a colocação de implantes dentários. Atualmente o material mais utilizado para o preenchimento de seio maxilar é o enxerto ósseo autógeno retirado de sítios intra ou extrabucais. Apesar desse procedimento ter sua eficácia comprovada clínica e histologicamente, nem sempre é bem tolerado pelos pacientes devido à morbidade associada à manipulação da área doadora. Por isso, vários substitutos ósseos vêm sendo desenvolvidos. A proteína óssea morfogenética recombinante humana-2 surgiu recentemente como uma alternativa aos enxertos autógenos, oferecendo excelente padrão de reparo e/ou neoformação óssea quando utilizada na reconstrução de rebordos alveolares, possibilitando a reabilitação com próteses implantossuportadas. Nesse trabalho foi feita uma revisão da literatura e apresentação de caso de levantamento de assoalho de seio maxilar bilateral com o uso da proteína óssea morfogenética.