Analysis of the Chemical Composition, Morphological Characterization, and Porosimetry of Allograft and Comparison with Xenograft for Dental Applications / Análisis de la Composición Química, Caracterización Morfológica y Porosimetría de Aloinjerto y Comparación con Xenoinjerto para Aplicaciones Odontológicas

SUMMARY: Tissue engineering aims to fabricate a scaffold that exhibits a suitable surface topography for a desired cellular response. Therefore, a study analyzing the characteristics of bone grafts is important for future research directions. This work aims to analyze the physical-chemical characteristics of commercially available bone grafts of human and bovine origin for dental use, using morphological analysis of the surface and chemical composition by variable pressure scanning electron microscope (VP-SEM) and energy-dispersive x-ray (EDX) spectrometry. In addition, pore diameter and surface area were analyzed by degassing method using a porosimeter, and particle size by laser diffraction. The analyzed allograft and xenograft particles differ in morphological characteristics and chemical composition. The allograft particles present a cuboidal and prismatic geometric morphology with angled edges and the absence of macropores. On the contrary, the xenograft particles present an irregular morphology with macropores in their structure. There is a statistically significant difference in C, P, and Ca between the xenograft and allografts (p < 0,05). The analyzed composition of allografts showed mainly the presence of C and O. In contrast, the composition of the xenograft was mainly Ca. These differences could influence the osteogenic properties of allografts and xenografts. This analysis provides basic information to understand the physicochemical properties of allografts and xenografts that facilitate cell-graft interaction.

La ingeniería de tejidos tiene como objetivo fabricar un andamio que muestre una topografía de superficie adecuada para una respuesta celular deseada. Por tanto, un estudio que analice las características de los injertos óseos es importante para futuros enfoques de investigación. Este trabajo tiene como objetivo analizar las características físico-químicas de injertos óseos de origen humano y bovino disponibles comercialmente para uso odontológico, mediante análisis morfológico de la superficie y composición química mediante microscopio electrónico de barrido de presión variable (VP-SEM) y x-dispersivo de energía. espectrometría de rayos (EDX). Además, el diámetro de los poros y el área superficial se analizaron mediante el método de desgasificación utilizando un porosímetro y el tamaño de las partículas mediante difracción láser. Las partículas de aloinjerto y xenoinjerto analizadas difieren en características morfológicas y composición química. Las partículas del aloinjerto presentan una morfología geométrica cúbica y prismática con bordes angulados y ausencia de macroporos. Por el contrario, las partículas de xenoinjerto presentan una morfología irregular con macroporos en su estructura. Existe una diferencia estadísticamente significativa en C, P y Ca entre el xenoinjerto y los aloinjertos (p < 0,05). La composición analizada de los aloinjertos mostró principalmente la presencia de C y O. Por el contrario, la composición del xenoinjerto fue principalmente Ca. Estas diferencias podrían influir en las propiedades osteogénicas de los aloinjertos y xenoinjertos. Este análisis proporciona información básica para comprender las propiedades fisicoquímicas de aloinjertos y xenoinjertos que facilitan la interacción célula-injerto.

Reparación tisular de los tejidos orales: una revisión de la literatura / Oral tissues healing: a review of the literature

El odontólogo realiza de forma rutinaria procedimientos que generan lesiones en los tejidos duros y blandos, por lo que resulta importante que el profesional conozca los procesos normales de cicatrización y reparación. La cicatrización es un fenómeno fisiológico que se presenta en cualquier tejido vivo que ha sido lesionado, que tiene importantes componentes vasculares y celulares que llevan una secuencia específica y que dependiendo de la magnitud de la lesión, el tejido podrá regenerar o cicatrizar según sea el caso. Asimismo, existen patologías sistémicas específicas y locales capaces de retrasar el proceso normal de cicatrización. El objetivo del presente artículo es explicar el proceso normal de reparación tisular de los tejidos orales y periorales (AU)

The dentist routinely performs procedures that generate injuries to hard and soft tissues, so it is important that the professional knows the normal healing and repair processes. Cicatrization is a physiological phenomenon that occurs in any living tissue that has been injured that has important vascular and cellular components that carry a specific sequence and that, depending on the magnitude of the lesion, the tissue may regenerate or heal as the case may be. Likewise, there are specific systemic and local pathologies capable of delaying the normal healing process. The aim of this article is to explain the normal tissue repair process of oral and perioral tissues (AU)

Fibroma ameloblástico mandibular: caso clínico / Fibroblastic fibroma mandibular: a clinical case

El fibroma ameloblástico (FA) se describe como una neoplasia benigna de origen odontogénico mixto que suele presentarse entre la primera y segunda década de vida, frecuentemente en los molares permanentes inferiores. Por lo general es asintomático, pero las lesiones de gran tamaño suelen acompañarse con dolor e inflamación. Su tratamiento por lo regular es conservador. Se describe el caso de un fibroma ameloblástico en un paciente de 13 años de edad, que involucraba cuerpo y ángulo mandibular izquierdo, tratado de manera conservadora, se realiza extirpación del tumor, regeneración ósea guiada y rehabilitación con implante dental (AU)

Ameloblastic fibroma (AF) is described as a benign neoplasm of mixed odontogenic origin that usually presents between the first and second decade of life, frequently in lower permanent molars. It is usually asymptomatic, but large lesions are usually accompanied by pain and inflammation. His treatment is generally conservative. The clinical case of an ameloblastic fibroma in a 13-year-old patient is described, involving the left mandibular body and angle, treated conservatively, tumor removal, guided bone regeneration and rehabilitation with dental implants are performed (AU)

Bioceramic scaffolds with two-step internal/external modification of copper-containing polydopamine enhance antibacterial and alveolar bone regeneration capability / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Magnesium-doped calcium silicate (CS) bioceramic scaffolds have unique advantages in mandibular defect repair; however, they lack antibacterial properties to cope with the complex oral microbiome. Herein, for the first time, the CS scaffold was functionally modified with a novel copper-containing polydopamine (PDA(Cu2+‍)) rapid deposition method, to construct internally modified (*P), externally modified (@PDA), and dually modified (*P@PDA) scaffolds. The morphology, degradation behavior, and mechanical properties of the obtained scaffolds were evaluated in vitro. The results showed that the CS*P@PDA had a unique micro-/nano-structural surface and appreciable mechanical resistance. During the prolonged immersion stage, the release of copper ions from the CS*P@PDA scaffolds was rapid in the early stage and exhibited long-term sustained release. The in vitro evaluation revealed that the release behavior of copper ions ascribed an excellent antibacterial effect to the CS*P@PDA, while the scaffolds retained good cytocompatibility with improved osteogenesis and angiogenesis effects. Finally, the PDA(Cu2+)-modified scaffolds showed effective early bone regeneration in a critical-size rabbit mandibular defect model. Overall, it was indicated that considerable antibacterial property along with the enhancement of alveolar bone regeneration can be imparted to the scaffold by the two-step PDA(Cu2+) modification, and the convenience and wide applicability of this technique make it a promising strategy to avoid bacterial infections on implants.

Demineralized freeze-dried bone allograft with/without i-Platelet-rich fibrin in 3 wall intrabony defects

Demineralized freeze-dried bone allograft (DFDBA) contains bone morphogenetic proteins (BMPs), hence is osteoinductive. Autologous platelet concentrates exhibit a higher quantity of growth factors. Both these biomaterials aid in bone regeneration when placed in three-wall intrabony defects. However, their efficacy when used alone and in conjugation is not clear. Aim: To assess clinical and radiographic efficacy of injectable platelet-rich fibrin (i-PRF) with microsurgical access flap in the treatment of three-wall intrabony defects in chronic periodontitis patients. Methods: Thirty sites with three-wall intrabony defects were randomly assigned to control and test group by computer generated method. The test group obtained i-PRF mixed with DFDBA while the control group received only DFDBA. Clinical parameters such as site-specific Plaque index (PI), Radiographic intrabony defect depth (IBDD), modified- Sulcular bleeding index (mSBI), Clinical attachment level (CAL), and Probing pocket depth (PPD) were measured at baseline, three and six months. Results: Intragroup comparison within the control group and test group exhibited statistically highly significant variation of mean PI, mSBI, PPD, CAL, and IBDD score from baseline to 3 months and from 3-6 months (p<0.001). However, intergroup comparison demonstrated no statistically significant variation of mean IBDD at all 3 intervals (p>0.05). Conclusion: i-PRF combined with DFDBA enhanced the radiographic and clinical parameters as opposed to DFDBA alone. The role of i-PRF is promising in its capacity for easy obtainability and increased potential to aid in regeneration

Validação biológica de grânulos de vidro bioativas (compostos por biovidro 45S5): estudo in vitro e in vivo / Biological validation of bioactive glass granules (composed of 45S5 bioglass): in vitro and in vivo study

O tecido ósseo, embora tenha a capacidade de regeneração, é limitado em sua eficácia diante de defeitos críticos que impedem a regeneração natural. Dessa forma, materiais como a hidroxiapatita (HA) têm sido considerados promissores na engenharia de tecido ósseo. Contudo, apesar de sua ampla utilização, a hidroxiapatita apresenta desvantagens, como a taxa de reabsorção e remodelação lenta. Em contraste, o biovidro 45S5 se destaca por sua biocompatibilidade, propriedades bioativas e degradabilidade. Este estudo objetivou avaliar o comportamento biológico in vitro e in vivo de grânulos de vidro bioativas de biovidro 45S5 fabricadas pelo método de fusão. Os biovidros foram caracterizados por meio da difração de raios X (DRX), espectroscopia de infravermelho por transformação de Fourier (FTIR), calorimetria diferencial de varredura (DSC) e espectrometria de emissão óptica com plasmas indutivamente acoplados (ICP OES). Em seguida, foi realizado o estudo in vitro, utilizando células osteoblásticas isoladas de fêmures de ratos, que foram submetidas a análise da morfologia celular (MEV), viabilidade celular (MTT), conteúdo de proteína total (PT), atividade de fosfatase alcalina (ALP) e formação de nódulos de mineralização. No estudo in vivo, foram realizados defeitos ósseos críticos de 7 mm na tíbia de coelhos da raça New Zealand, que foram divididos em dois grupos (n=6) de acordo com o material de preenchimento: hidroxiapatita comercial (HA) e biovidro 45S5 (BG45S5). Após 2, 8 e 12 semanas, os animais foram eutanasiados e as peças ósseas foram submetidas as análises histológicas e histomorfométricas. Os dados foram submetidos ao teste de normalidade Shapiro-Wilk (p=0,05) e quando normais realizamos o teste t de student e quando não normais realizamos o teste de Mann-Whitney. Os resultados dos testes físico-químicos mostraram sucesso na produção do novo biomaterial. Nos testes in vitro, observou-se que o grupo BG45S5 não apresentou citotoxicidade e mostrou-se promissor com diferença estatisticamente significante em relação ao grupo hidroxiapatita comercial (p=0.0263). Nos testes de PT, ALP e nódulos de mineralização, os grupos não apresentaram diferença estatística entre eles (p<0,05). Contudo, o grupo BG45S5 mostrou-se promissor em relação aos outros grupos. Na análise histológica, ambos os grupos apresentaram neoformação óssea nos defeitos após 2, 8 e 12 semanas. Na histomorfometria, observou-se que os grupos BG45S5 e HA apresentaram maior área de neoformação óssea em 12 semanas. Houve diferença estatisticamente significante entre os grupos no tempo de 2 semanas, com maior neoformação para o grupo BG45S5. Apesar dos resultados promissores do grupo BG45S5, não houve diferença estatisticamente significativa entre os grupos (p<0,05) nos tempos de 8 e 12 semanas. Em resumo, os resultados evidenciaram o sucesso na produção do biomaterial sintético e o potencial do biomaterial BG45S5 como um material promissor para tratamento de defeitos ósseos críticos. (AU)

Bone tissue, despite its capacity of regeneration, is limited in its effectiveness when faced with critical defects that prevent natural regeneration. Therefore, materials such as hydroxyapatite (HA) have been considered promising in bone tissue engineering. However, despite its wide use, hydroxyapatite has disadvantages, such as slow resorption and remodeling rates. In contrast, 45S5 bioglass stands out for its biocompatibility, bioactive properties and degradability. This study aimed to evaluate the in vitro and in vivo biological behavior of bioactive 45S5 bioglass beads manufactured by the melt quenched method. The bioglasses were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and inductively coupled plasma optical emission spectrometry (ICP OES). Following this, an in vitro study was conducted using osteoblastic cells isolated from rat femurs, which were subjected to analysis of cell morphology (SEM), cell viability (MTT), total protein content (TP), alkaline phosphatase activity (ALP) and mineralization nodule formation. In the in vivo study, critical bone defects of 7 mm were created in the tibia of New Zealand rabbits, which were divided into two groups (n=6) according to the filling material: commercial hydroxyapatite (HA) and bioactive glass 45S5 (BG45S5). After 2, 8, and 12 weeks, the animals were euthanized and the bone pieces were subjected to histological and histomorphometric analyses. Data were subjected to the Shapiro-Wilk normality test (p=0.05), and when normal, we performed the Student's t-test, and when non-normal, we performed the Mann-Whitney test. The results of the physicochemical tests showed success in the production of the new biomaterial. In the in vitro tests, it was observed that the BG45S5 group did not present cytotoxicity and showed promise with a statistically significant difference compared to the commercial hydroxyapatite group (p=0.0263). In the TP, ALP and mineralization nodule tests, the groups showed no statistical difference between them (p<0.05). However, the BG45S5 group showed promise compared to the other groups. In the histological analysis, both groups showed new bone formation in the defects after 2, 8, and 12 weeks. In the histomorphometric analysis, it was observed that the BG45S5 and HA groups presented a larger area of new bone formation at 12 weeks. There was a statistically significant difference between the groups at 2 weeks, with greater new formation for the BG45S5 group. Despite the promising results of the BG45S5 group, there was no statistically significant difference between the groups (p<0.05) at 8 and 12 weeks. In summary, the results evidenced the successful production of the synthetic biomaterial and the potential of the BG45S5 bioglass as a promising material for treating critical bone defect.(AU)

Biological evaluation of critical bone defect regeneration using hydroxyapatite/ alginate composite granules

Purpose: to evaluate biocompatibility and osteogenic potential of hydroxyapatite/alginate composite after its implantation on rat calvarian critical bone defect. Methods: thirty adults male Wistar rats were randomly distributed into two groups: GHA ­ critical bone defect filled with hydroxyapatite/alginate composite granules (HA/Alg) and CG ­ critical bone defect without biomaterial; evaluated at biological points of 15, 45 and 120 days. Results: the histomorphometrically analyses for GHA showed osteoid matrix deposition (OM) among the granules and towards the center of the defect in centripetal direction throughout the study, with evident new bone formation at 120 days, resulting in filling 4/5 of the initial bone defect. For CG, this finding was restricted to the edges of the bone margins and formation of connective tissue on the residual area was found in all biological points. Inflammatory response on GHA was chronic granulomatous type, discrete and regressive for all biological points. Throughout the study, the CG presented mononuclear inflammatory infiltrate diffuse and regressive. Histomorphometry analyses showed that OM percentage was evident for GHA group when compared to CG group in all analyzed periods (p > 0.05). Conclusions: the biomaterial evaluated at this study showed to be biocompatible, bioactive, osteoconductive and biodegradable synchronously with bone formation.

Histomorphometric comparison of two different preclinical models to evaluate the bone repair in grafted areas

Aim: This study was performed to compare two different rat defect models (critical calvaria defects versus guided bone regeneration in the mandibular ramus) used to evaluate bone repair in grafted areas. Methods: A total of 12 rats were allocated in two groups according the experimental model used to evaluate the bone repair in grafted areas: a critical sized-calvaria defect of 5 mm filled with bone graft (n=6) and a mandibular ramus filled with the bone graft associated with a Teflon dome-shaped membrane (n=6). Both groups were grafted with deproteinized bovine bone graft. After 60 days, the animals were euthanized and the samples obtained were submitted to histomorphometry analysis to evaluate the relative amount of bone, remaining bone substitute, and soft tissue within the grafted areas. Results: No differences were observed between the preclinical models evaluated in relation to the amount of bone tissue formation (19.93 ± 4.55% in calvaria vs. 21.00 ± 8.20% in mandible). However, there was a smaller amount of soft tissue (43.20 ± 10.97% vs. 57.79 ± 7.61 %; p<0.01) and a greater amount of bone substitute remaining (35.80 ± 5.52% vs. 22.28 ± 4.36 %; p<0.05) in the grafted areas in the mandible compared to calvaria defect. Conclusion: Preclinical models for the analysis of bone repair in grafted areas in the mandible and critical sized-calvaria defects showed different responses in relation to the amount of soft tissue and bone substitute remnants

Avaliação in vitro da fotobiomodulação das SHEDs semeadas em um scaffold de osso bovino mineral desproteinizado e colagenado / In vitro evaluation of photobiomodulation of Stem cells from human exfoliated deciduous teeth seeded in a deproteinized bovine bone mineral with 10% collagen scaffold

A regeneração óssea é um processo importante para oferecer tratamentos reconstrutivos mais rápidos e eficientes, no entanto, limitações técnicas continuam sendo um desafio, assim como a velocidade de formação e maturação óssea. Portanto, as pesquisas têm se voltado para técnicas alternativas na regeneração óssea e atualmente, a engenharia tecidual tem estudado o uso de células tronco para tratamento de perdas ósseas. A eficácia e a taxa de sucesso das diferentes técnicas e scaffolds foram avaliadas. Porém, há pouca informação sobre a eficácia combinada de carreadores xenógenos, células tronco de dentes decíduos esfoliados humano (SHEDs) e a terapia de fotobiomodulação (PBMT) na regeneração de defeitos ósseos. Baseado em estudos prévios, a proposta deste estudo foi avaliar, in vitro, a ação da PBMT, uma técnica com propriedades imunomodulatórias, angiogênicas e com capacidade de aumentar a adesão, proliferação e migração celular ao biomaterial tridimensional de osso bovino mineralizado desproteinizado com colágeno suíno a 10% (OBMDC), semeado com SHEDs, para acelerar e aumentar a taxa de formação óssea. Foi utilizado o laser de diodo, com comprimento de onda de 660nm; 40mW de potência; 3J/cm2 de densidade de energia e 2 segundos de tempo de aplicação após 24h e 72h do plaqueamento. Para avaliar a proliferação, as SHEDs foram descongeladas cultivadas, plaqueadas, semeadas no scaffold de OBMDC e divididas em 8 grupos: 1) Controle 15%; 2) Controle 5%; 3) OBMDC 15%; 4) OBMDC 5%; 5) Laser 15%; 6) Laser 5%; 7) OBMDC-L 15%; 8) OBMDC-L 5% e a análise de proliferação foi realizada por MTT. Para avaliar diferenciação celular, as amostras foram divididas em quatro grupos: 1) Grupo Controle clonogênico: SHEDs cultivadas em meio clonogênico; 2) Grupo Controle mineralizante: SHEDs cultivadas em meio mineralizante; 3) Grupo laser clonogênico: SHEDs cultivadas em meio clonogênico com aplicação de laser; 4) Grupo laser mineralizante: SHEDs cultivada em meio mineralizante com aplicação de laser. Para o grupo laser, as células foram irradiadas no período de 24h e 72h após o plaqueamento e todas as amostras fixadas para análise da formação dos depósitos de cálcio, através do ensaio de vermelho de alizarina após 23 dias de cultivo celular e os dados foram tratados estatisticamente (p0,05). Para avaliar a morfologia celular das SHEDs em todos os grupos, utilizou-se o microscópio invertido de fase em 24h e 72h após o plaqueamento. O grupo OBMDC-L 5% SFB em 72h, demonstrou maior proliferação celular que o grupo Controle (p=0.0286). O grupo laser no meio mineralizante apresentou maior formação de depósito de matriz mineralizada em comparação ao grupo controle em meio clonogênico, controle em meio mineralizante e laser em meio clonogênico (p<0,0001). Considerando as condições experimentais deste estudo, concluiu-se que, in vitro, as SHEDs, semeadas em scaffold OBMDC, proliferaram mais após 2 aplicações de PBMT e houve diferenciação osteogênica das células após 23 dias em meio mineralizante.

Neo-osteogenesis using an intentionally exposed polypropylene membrane after tooth extraction versus guided bone regeneration technique: a single-blind randomized controlled trial / Neo-osteogénesis utilizando una membrana de polipropileno expuesta intencionalmente después de la extracción del diente versus técnica de regeneración ósea guiada: ensayo clínico aleatorizado ciego / Neo-osteogênese utilizando uma membrana de polipropileno exposta intencionalmente após extração dentária versus técnica de regeneração óssea guiada: ensaio clínico randomizado e cego

Introduction: The intentionally exposed polypropylene (PP) membrane has been proposed for guided bone regeneration (GBR) of the alveo lar bone after extraction; however, there are biological limitations to this proposal. This study aimed to describe the effects of the PP membrane on neo-osteogenesis after tooth extraction, comparing to intentionally ex posed and primary soft tissue coverage techniques. Methodology: This clinical trial followed the TIDieR checklist and guide. Clinical and histo logical parameters of alveolar repair were compared between groups: 1 (control group), without regenerative procedure; 2, GBR; and 3, inten tionally exposed membrane. Results: Group 3 showed slight effect on the quality of new bone, compared to the control group. Although the GBR was underestimated by the early exposure of the membrane, alveo lar repair and newly formed bone were superior to the other groups. Poly propylene membrane intentionally exposed compromised the volume density of the immature and mineralized bone matrix, the osteoblast and osteocyte count, and stimulated the granulation tissue formation and local inflammatory infiltrate. Conclusions: Despite the exposure of the PP membrane in GBR, this technique improved the quality of new bone and alveolar repair compared to the surgical technique of intentional exposure and alveolus only sutured.

RESUMEN Introducción: La membrana de polipropileno (PP) intencionalmente expuesta ha sido propuesta para la regeneración ósea guiada (GBR) del hueso alveolar después de la extracción; sin embargo, existen limitaciones biológicas a esta propuesta. Este estudio tuvo como objetivo describir los efectos de la membrana de PP en la neo-osteogénesis después de la extracción del diente, en comparación con las técnicas de cobertura de tejido blando primarias y expuestas intencionalmente. Metodología: Este ensayo clínico siguió la lista de verificación y la guía TIDieR. Se compararon los parámetros clínicos e histológicos de la reparación alveolar entre los grupos: 1 (grupo control), sin procedimiento regenerativo; 2, GBR; y 3, membrana expuesta intencionalmente. Resultados: el grupo 3 mostró un ligero efecto sobre la calidad del hueso nuevo, en comparación con el grupo de control. Aunque la GBR fue subestimada por la exposición temprana de la membrana, la reparación alveolar y el hueso neoformado fueron superiores a los otros grupos. La membrana de polipropileno expuesta intencionalmente comprometió la densidad de volumen de la matriz ósea inmadura y mineralizada, el recuento de osteoblastos y osteocitos, y estimuló la formación de tejido de granulación y el infiltrado inflamatorio local. Conclusiones: A pesar de la exposición de la membrana de PP en GBR, esta técnica mejoró la calidad del hueso nuevo y la reparación alveolar en comparación con la técnica quirúrgica de exposición intencional y alvéolo solo suturado.

Introdução: A membrana de polipropileno (PP) intencionalmente exposta tem sido proposta para regeneração óssea guiada (ROG) do osso alveolar após exodontia; no entanto, existem limitações biológicas a esta proposta. Este estudo teve como objetivo descrever os efeitos da membrana de PP na neo-osteogênese após a extração dentária, comparando com as técnicas de exposição intencional e cobertura primária de tecidos moles. Metodologia: Este ensaio clínico seguiu a lista de verificação e o guia TIDieR. Parâmetros clínicos e histológicos do reparo alveolar foram comparados entre os grupos: 1 (grupo controle), sem procedimento regenerativo; 2, GBR; e 3, membrana intencionalmente exposta. Resultados: O Grupo 3 apresentou leve efeito na qualidade do novo osso, em comparação com o grupo controle. Embora o GBR tenha sido subestimado pela exposição precoce da membrana, o reparo alveolar e o osso neoformado foram superiores aos outros grupos. A exposição intencional da membrana de polipropileno comprometeu a densidade volumétrica da matriz óssea imatura e mineralizada, a contagem de osteoblastos e osteócitos e estimulou a formação de tecido de granulação e infiltrado inflamatório local. Conclusões: Apesar da exposição da membrana PP na ROG, esta técnica melhorou a qualidade do novo osso e da reparação alveolar em comparação com a técnica cirúrgica de exposição intencional e alvéolo apenas suturado.

Estudio de biocompatibilidad de matrices poliméricas combinadas, responsivas al pH, con aplicación en Ingeniería de Tejido Óseo / Biocompatibility study of combined pH-responsive polymeric matrices with application in Bone Tissue Engineering

El presente trabajo muestra la obtención de un material a partir de un polímero sintético (TerP) y otro natural, mediante entrecruzamiento físico y su caracterización fisicoquímica y biológica, con el fin de emplearlos para regeneración de tejido óseo. Las membranas fueron obtenidas por la técnica de evaporación del solvente y caracterizadas por espectroscopia FTIR, ensayos de hinchamiento, medidas de ángulo de contacto y microscopia electrónica de barrido (SEM). Se encontró que la compatibilidad entre los polímeros que la constituyen es estable a pH fisiológico y que, al incorporar mayor cantidad del TerP a la matriz, esta se vuelve más hidrofóbica y porosa. Además, teniendo en cuenta la aplicación prevista para dichos materiales, se realizaron estudios de biocompatibilidad y citotoxicidad con células progenitoras de médula ósea (CPMO) y células RAW264.7, respectivamente. Se evaluó la proliferación celular, la producción y liberación de óxido nítrico (NO) al medio de cultivo durante 24 y 48 horas y la expresión de citoquinas proinflamatorias IL-1ß y TNF-α de las células crecidas sobre los biomateriales variando la cantidad del polímero sintético. Se encontró mayor proliferación celular y menor producción de NO sobre las matrices que contienen menos proporción del TerP, además de poseer una mejor biocompatibilidad. Los resultados de este estudio muestran que el terpolímero obtenido y su combinación con un polímero natural es una estrategia muy interesante para obtener un biomaterial con posibles aplicaciones en medicina regenerativa y que podría extenderse a otros sistemas estructuralmente relacionados. (AU)

In the present work, the preparation of a biomaterial from a synthetic terpolymer (TerP) and a natural polymer, physically crosslinked, is shown. In order to evaluate the new material for bone tissue regeneration, physicochemical and biological characterizations were performed. The membranes were obtained by solvent casting and characterized using FTIR spectroscopy, swelling tests, contact angle measurements, and scanning electron microscopy (SEM). It was found that the compatibility between the polymers is stable at physiological pH and the incorporation of a higher amount of TerP into the matrix increases hydrophobicity and porosity.Furthermore, considering the intended application of these materials, studies of biocompatibility and cytotoxicity were conducted with Bone Marrow Progenitor Cells (BMPCs) and RAW264.7 cells, respectively. Cell proliferation, NO production and release into the culture medium for 24 and 48 hours, and proinflammatory cytokine expression of IL-1ß and TNF-α from cells grown on the biomaterials while varying the amount of the synthetic polymer were evaluated. Greater cell proliferation and lower NO production were found on matrices containing a lower proportion of TerP, in addition to better biocompatibility. The results of this study demonstrate that the obtained terpolymer and its combination with a natural polymer is a highly interesting strategy for biomaterial preparation with potential applications in regenerative medicine. This approach could be extended to other structurally related systems. (AU)

Characterization of the Masquelet Induced Membrane Technique in a Murine Segmental Bone Defect Model / Caracterização da membrana induzida pela técnica de Masquelet em modelo murino de defeito ósseo segmentar

Abstract Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208μm) than at four (186.9 ± 70.21μm, p = 0.0002) and two weeks (252.2 ± 55.1μm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.

Resumo Objetivo Reproduzir em modelo animal a técnica cirúrgica de Masquelet utilizada no tratamento de defeitos ósseos críticos e analisar as características da membrana formada em torno do cimento ósseo. Métodos Um defeito crítico de 10mm foi realizado na diáfise femoral de 21 ratos Sprague-Dawley. Após a ressecção da porção central da diáfise o defeito foi estabilizado com fio de Kirschner introduzido pelo canal medular e com a interposição de espaçador de cimento ósseo. Após 2, 4, e 6 semanas do procedimento cirúrgico os animais foram eutanasiados e avaliados em radiografias do membro posterior quanto ao tamanho do defeito, o alinhamento e a estabilidade da osteossíntese. As membranas formadas em torno do espaçador foram submetidas a análise histológica para avaliação da espessura, da maturação do tecido conjuntivo e da densidade vascular. Resultados Ao longo do tempo as membranas inicialmente constituídas por tecido conjuntivo frouxo foram substituídas por membranas representadas por tecido conjuntivo denso, rico em fibras colágenas espessas. Com seis semanas a espessura das membranas foi maior (565 ± 208μm) do que com quatro (186,9 ± 70,21μm, p = 0,0002) e duas semanas (252,2 ± 55,1μm, p = 0,001). Todas as membranas do tempo inicial apresentaram focos de diferenciação osteogênica que reduziram progressivamente ao longo do tempo. Conclusão Além da função estrutural e protetora da membrana, suas características biológicas intrínsecas podem contribuir ativamente para a regeneração óssea. A atividade biológica atribuída pela presença de focos de osteogênese confere à membrana potencial de osteoindução que favorece as condições locais para a integração do enxerto ósseo.

Regeneração óssea guiada para aumento horizontal de rebordo utilizando fibrina rica em plaquetas associada a enxertos ósseos: revisão de literatura / Guided bone regenerationfor horizontal bone augmentation using platelet- rich fibrin associated with bone grafts: literature review

Objetivo: revisar a literatura sobre os diferentes tipos de derivados de plaquetas autólogas e o desempenho clínico do uso do sticky bone para aumento ósseo horizontal de rebordo. Materiais e métodos: Para realização dessa revisão foram realizadas buscas nas bases de dados PubMed, Google Scholar e Web of Science, utilizando os seguintes descritores: "platelet-rich fibrin" AND "sticky bone" OR "alveolar bone grafting" AND "sticky bone" OR "guided bone regeneration" AND "sticky bone" AND "alveolar ridge augmentation" OR "Alveolar ridge augmentation" AND "sticky bone". Foram incluídos artigos publicados em inglês, que abordavam conceitos relacionados aos agregados plaquetários e a regeneração óssea guiada para aumento ósseo horizontal de rebordo utilizando fibrina rica em plaquetas associada à enxertos ósseos (sticky bone). Resultados: Após avaliação dos estudos encontrados foram selecionados 11 artigos sobre o uso do sticky bone para aumento horizontal de rebordo. Para compor este trabalho foram selecionados também 14 estudos de revisão e artigos associados ao tema. Por ser de fácil aplicação e obtenção, muitos autores têm estudado as aplicações cirúrgicas do sticky bone e os resultados demonstram que o aumento horizontal do rebordo utilizando essa técnica pode ser realizado de forma previsível. Conclusão: apesar de haver estudos promissores sobre o uso do sticky bone, falta evidência na literatura sobre seu sucesso clínico. Assim, para compreender o potencial regenerativo desta técnica são necessários um maior número de estudos randomizados, com diferentes materiais de enxerto e protocolos padronizados de obtenção do sticky bone.(AU)

Objective: to review the literature on the different types of autologous platelet derivatives and the clinical performance of using sticky bone for horizontal bone ridge augmentation. Materials and methods: In order to conduct this review, it was conducted searches in the PubMed, Google Scholar, and Web of Science databases using the following descriptors: "platelet-rich fibrin" AND "sticky bone" OR "alveolar bone grafting" AND "sticky bone" OR "guided bone regeneration" AND "sticky bone" AND "alveolar ridge augmentation" OR "Alveolar ridge augmentation" AND "sticky bone". It included articles published in English that addressed concepts related to platelet aggregates and guided bone regeneration for horizontal bone augmentation using platelet-rich fibrin associated with bone grafts (sticky bone). Results: After evaluating the studies found, were selected 11 articles on the use of sticky bone for horizontal ridge augmentation. To compose this work, 14 review studies and articles associated with the topic were also selected. Due to its ease of application and availability, many authors have explored the surgical applications of sticky bone, and the results indicate that horizontal ridge augmentation using this technique can be predictably performed. Conclusion: while there are promising studies on the use of sticky bone, the literature lacks evidence regarding its clinical success. Therefore, to fully understand the regenerative potential of this technique, further randomized studies are needed, involving different graft materials and standardized protocols for obtaining sticky bone.(AU)

Uso de microvibración e inhibidores de la catepsina K en tratamientos de regeneración ósea dental / Use of micro-vibration and cathepsin K inhibitors in dental bone regeneration treatments

Introducción: el hueso está en remodelación constante para mantener la estructura del esqueleto, tener un ciclo de resorción por los osteoclastos y formación de hueso nuevo a cargo de los osteoblastos; el hueso también es susceptible a enfermedades sistémicas, traumas, edad y trastornos genéticos que afectarán el remodelado óseo, produciendo una pérdida masiva de masa ósea regulado por hormonas, citocinas, enzimas, etcétera. El objetivo es realizar una revisión sistemática de artículos que muestren cambio o alteración al utilizar tratamientos con microvibraciones y farmacológicos sobre la catepsina K en el hueso alveolar. Material y métodos: para realizar una comparación entre la efectividad del tratamiento a base de microvibraciones y con inhibidores de la catepsina K, se realizó una revisión sistemática en nueve bases de datos (Wiley Online Library, PubMed, Google Academic, Scopus, ScienceDirect, SciELO, Medline, EBSCO y Springer Link). La población de estudio fueron ratas y ratones. Resultados: en este estudio se incluyeron 20 artículos cuya investigación se realizó en estudios clínicos. En los resultados podemos observar cómo todos los tratamientos de alguna forma mejoran el proceso de remodelado óseo. Es difícil comparar cuál de los tratamientos dentro de cada grupo es mejor que otro, debido a que los resultados expresados son cualitativos. Conclusión: acorde a los resultados expresados se opta por realizar un tratamiento con microvibraciones debido a que el uso de inhibidores de la catepsina K aún no se encuentra completamente desarrollado y no se comprenden sus consecuencias debido a su manera sistémica de actuar (AU)

Introduction: the bone is in constant remodeling to maintain the skeletal structure, having a cycle of resorption by osteoclasts and formation of new bone by osteoblasts, the bone is also susceptible to systemic diseases, trauma, age and genetic disorders that affect bone remodeling, producing a massive loss of bone mass regulated by hormones, cytokines, enzymes, etcetera. The objective is to perform a systematic review of articles that show a change or alteration when using micro-vibration and pharmacological treatments on cathepsin K in the alveolar bone. Material and methods: in order to make a comparison between the effectiveness of micro-vibration and cathepsin K inhibitor treatments, a systemic review was carried out in nine databases (Wiley Online Library, PubMed, Google Academic, Scopus, ScienceDirect, SciELO, Medline, EBSCO and Springer Link). The study population was rats and mice. Results: this study included 20 articles whose research was carried out in clinical studies. In the results we can see how all the treatments in some way improve the bone remodeling process, it is difficult to compare which treatment within each group is better than the other, because the results expressed are qualitative. Conclusion: according to the results expressed, it is decided that it is better to perform a treatment with micro vibrations because the use of cathepsin K inhibitors are not yet fully developed and their consequences are not understood due to their systemic way of acting (AU)

Necesidad de regeneración ósea en la instalación de implantes: Análisis Retrospectivo de 7 años, Hospital San Camilo / Need for bone regeneration in the installation of implants: 7-years retrospective analysis, San Camilo Hospital

Objetivo: Analizar la necesidad de regeneración ósea guiada en pacientes sometidos a terapia implantológica entre el año 2012 y 2019 del Hospital San Camilo, San Felipe. Material y Método: Estudio observacional retrospectivo. Se incluyeron todos los pacientes pertenecientes al programa de implantes entre el 2012 y 2019. Los pacientes fueron organizados de acuerdo a la edad, género, marca de implante, uso de injerto, tiempo de carga y tasa de pérdida. Estos datos se evaluaron empleando estadística descriptiva calculando frecuencias y porcentajes en tablas de contingencias. Resultados: Se incluyeron 182 pacientes. La distribución por sexo fue de 121 mujeres y 61 hombres. La edad promedio de los pacientes fue de 51,23 años. El 41,76% casos del total requirió ROG. El 74,3% del grupo de implantes unitarios requirió injerto óseo. Sólo un 4,71% del grupo de sobredentadura requirió de injerto óseo. El tiempo de carga promedio fue de 3,68 meses. La tasa de pérdida en implantes fue de 3,85%. Conclusiones: El conocimiento y análisis de estos datos permite replantear la distribución de los recursos con el fin de realizar tratamientos más predecibles, disminuyendo las complicaciones y generando un ahorro de presupuesto.

Objective: To determine and analyze the need for guided bone regeneration (GBR) in patients who underwent implant therapy between 2012 and 2019 at the San Camilo Hospital, San Felipe. Material and methods: Retrospective observational study. All patients belonging to the implant program were included, with the need for either single implants or overdentures, which were installed between 2012 and 2019. Patients were organized according to their age, gender, implant brand, use of graft, loading time and loss rate. These data were evaluated using descriptive statistics calculating frequencies and percentages in contingency tables. Results: A total of 182 cases of implants were included. The distribution by sex was 121 women and 61 men. The average age of the patients was 51,23 years. The percentage of cases that required GBR was 41.76%. In the single implant group, 74.3% of cases required bone grafting. In the overdenture group, only 4.71% required bone grafting. The average loading time was 3,68 months. The implant loss rate was 3,85%. Conclusions: The knowledge and analysis of these data allow us to evaluate the distribution of resources to carry out more predictable treatments to reduce complications and generate budget savings.

Use of enamel matrix- derived proteins combined with bone graft for the treatment of intrabony defects: overview of reviews (FRISBEE review) / Uso de proteínas derivadas de la matriz del esmalte combinado con injerto óseo para el tratamiento de defectos intraóseos: resumen estructurado de revisiones sistemáticas (revisión FRISBEE)

Introduction: The use of enamel matrix-derived proteins (EMD) has increased in recent years due to their tissue-inducing properties that support periodontal regeneration. This study is an overview of systematic reviews with FRISBEE methodology on the use of EMD alone or combined with autologous bone graft materials (BGM) in the treatment of intrabony defects. Materials and Methods: A systematic search in the Epistemonikos database was performed. RevMan 5.3 and GRADEpro were used for data analysis and presentation Results: Four systematic reviews and two clinical trials were identified. All studies analysed change in probing depth, clinical attachment level, gingival margin level and bone defect depth (all changes in favour of EMD+BGM groups: mean difference (MD): 0.37 mm more, MD: 0.7 mm more, MD: 0.3 mm less, MD: 0.75 more, respectively). Conclusions: Adding autologous bone graft to EMD to treat intrabony defects showed better results, but not a relevant clinical difference compared to the use of EMD alone.

Introducción: El uso de proteínas derivadas de la matriz del esmalte (EMD) ha aumentado en los últimos años debido a sus propiedades inductoras de tejidos que apoyan la regeneración periodontal. Este estudio es una revisión sistemática de revisiones sistemáticas utilizando metodología FRISBEE sobre el uso de EMD solo o combinado con materiales injerto óseo autólogo (BGM) en el tratamiento de defectos intraóseos. Materiales y Métodos: Se realizó una búsqueda sistemática en la base de datos Epistemonikos. Se utilizaron RevMan 5.3 y GRADEpro para el análisis y la presentación de los datos. Resultados: Se identificaron cuatro revisiones sistemáticas y dos ensayos clínicos. Todos los estudios analizaron el cambio en la profundidad de sondaje, el nivel de inserción clínica, el nivel del margen gingival y la profundidad del defecto óseo (todos los cambios a favor de los grupos EMD+BGM: MD: 0,37 mm más, media de diferencia (MD): 0,7 mm más, MD: 0,3 mm menos, MD: 0,75 más, respectivamente). Conclusión: La adición de injerto óseo autólogo a la EMD para tratar defectos intraóseos mostró mejores resultados, pero no una diferencia clínica relevante en comparación con el uso de la EMD sola.

Progress in Application of Concentrated Growth Factor in Oral Tissue Regeneration / 中国医学科学院学报

Tissue regeneration is an important engineering method for the treatment of oral soft and hard tissue defects.Growth factors,as one of the three elements of tissue regeneration,are a necessary condition for tissue regeneration.Concentrated growth factor(CGF)is a new generation of blood extract prepared by changing the centrifugal speed on the basis of the preparation of platelet-rich plasma(PRP)and platelet-rich fibrin(PRF).It contains abundant growth factors and a fibrin matrix with a three-dimensional network structure,being capable of activating angiogenesis and promoting tissue regeneration and healing.CGF has been widely used in the repair and regeneration of oral soft and hard tissues.This paper introduces the preparation and composition of CGF and reviews the application of CGF in oral implantation and the regeneration of oral bone tissue,periodontal tissue,and dental pulp tissue.

Research updates of osteoimmunomodulation in osteogenesis / 细胞与分子免疫学杂志

The gold-standard for bone substitution of large bone defects continues to be autogenous bone graft. Artificial bone substitutes are difficult to replace the autogenous bone grafting due to excessive immune response, fast biodegradation characteristics and inappropriate biocompatibility. Given these drawbacks, osteoimmunology and its advanced functional biomaterials have gained growing attention in recent years. Immune system plays an essential role during bone healing via regulating the shift from inflammatory to anti-inflammation phenotype, and inflammatory cytokines response. The inflammatory reaction mainly include infiltration of immune cells (such as macrophages, neutrophils, T cells, B cells, etc) and release of inflammatory factors (such as IL-1β, IL-6, TNF-α, etc.) at the bone defects, which subsequently affect the step-wised process of bone healing rejuvenation. Hence, advanced bone biomaterials with immunomodulatory properties is of great significance for the treatment of patients with recalcitrant bone defects, especially for delayed healing or non-union. The reciprocal mechanism of immuno-modulated bone healing, however, is not fully understood and more research is required in the future.

Oligonucleotide drugs and their progress in stomatology / 中华口腔医学杂志

Oligonucleotide drugs have the characteristics of targeting, modifiability and high biosafety. Recent studies have shown that oligonucleotide can be used to make biosensors, vaccine adjuvants, and has the functions of inhibiting alveolar bone resorption, promoting jaw and alveolar bone regeneration, anti-tumor, destroying plaque biofilm, and precise control of drug release. Therefore, it has a broad application prospect in the field of stomatology. This article reviews the classification, action mechanism and research status of oligonucleotide in stomatology. The aim is to provide ideas for further research and application of oligonucleotide.

Role of collagen membrane in modified guided bone regeneration surgery using buccal punch flap approach: A retrospective and radiographical cohort study / 北京大学学报(医学版)

OBJECTIVE@#To investigate whether the placement of absorbable collagen membrane increase the stability of alveolar ridge contour after guided bone regeneration (GBR) using buccal punch flap.@*METHODS@#From June 2019 to June 2023, patients who underwent GBR using buccal punch flap simultaneously with a single implant placement in posterior region (from first premolar to second molar) were divided into coverage group, in which particular bone graft was covered by collagen membrane and non-coverage group. Cone beam CT (CBCT) was taken before surgery (T0), immediately after surgery (T1), and 3-7 months after surgery (T2), and the thickness of the buccal bone plate at different levels (0, 2, 4, and 6 mm) below the smooth-rough interface of the implant (BBT-0, -2, -4, -6) was mea-sured after superimposition of CBCT models using Mimics software.@*RESULTS@#A total of 29 patients, including 15 patients in coverage group and 14 patients in non-coverage group, were investigated in this study. At T0, T1, and T2, there was no significant difference in BBT between the two groups (P>0.05). At T1, BBT-0 was (2.50±0.90) mm in the coverage group and (2.97±1.28) mm in the non-coverage group, with corresponding BBT-2 of (3.65±1.08) mm and (3.58±1.26) mm, respectively. At T2, BBT-0 was (1.22±0.55) mm in the coverage group and (1.70±0.97) mm in the non-coverage group, with corresponding BBT-2 of (2.32±0.94) mm and (2.57±1.26) mm, respectively. From T1 to T2, there were no statistically significant differences in the absolute values [(0.47±0.54)-(1.33±0.75) mm] and percentages [(10.04%±24.81%)-(48.43%±18.32%)] of BBT change between the two groups. The thickness of new bone formation in the buccal bone plate from T0 to T2 ranged from (1.27±1.09) mm to (2.75±2.15) mm with no statistical difference between the two groups at all levels.@*CONCLUSION@#In the short term, the GBR using buccal punch flap with or without collagen membrane coverage can effectively repair the buccal implant bone defect. But collagen membrane coverage showed no additional benefit on alveolar ridge contour stability compared with non-membrane coverage.