Experimental protocol for evaluation of biomaterials in an in-vivo silicone implant coverage.

PURPOSE: To describe an experimental surgical model in rats using a dual-plane technique for evaluation of biomaterials in an in-vivo silicone implant coverage. METHODS: This study was developed following the ISO 10993-6 standard. In this study, 40 male Wistar rats weighing between 250 and 350 g were used, distributed into two groups: experimental, biomaterial superimposed on the minimammary prosthesis (MP); and control, MP without implantation of the biomaterial, with eight animals at each biological point: 1, 2, 4, 12, and 26 weeks. Thus, at the end of biological points (1, 2, 4, 12, and 26 weeks; n = 8 animals per week), the tissue specimens achieved were fixed in buffered formalin and stained with hematoxylin-eosin. RESULTS: Macroscopically, throughout the study, no postoperative complications were apparent. In the histological analysis, it was possible to observe the evolution of the inflammatory response, tissue repair, and fibrous capsule during the biological points. CONCLUSIONS: The experimental model described in this study proved to be suitable for evaluating the biomaterial used in the coverage of breast silicone implants.

Histomorphometric Study of Non-critical Bone Defect Repair after Implantation of Magnesium-substituted Hydroxyapatite Microspheres.

Objective The present study aims to analyze histomorphometrically the repair of a non-critical bone defect after implantation of hydroxyapatite (HA) microspheres substituted by magnesium (Mg). Methods Thirty rats were distributed into 3 experimental groups, evaluated at 15 and 45 days postoperatively: HAG (bone defect filled with HA microspheres); HAMgG (bone defect filled with HA microspheres replaced with 1 mol% Mg), and CG (bone defect without implantation of biomaterials). Results After 15 days, the biomaterials filled the entire defect extent, forming a new osteoid matrix between the microspheres. In the CG, this neoformation was restricted to the edges with the deposition of loose connective tissue with reduced thickness. At 45 days, new bone formation filled almost the entire extension of the bone defect in the 3 groups, with statistically significant osteoid deposition in the CG despite the reduced thickness compared with the HAG and HAMgG. The groups with biomaterial implantation displayed a more abundant osteoid matrix than at 15 days. Conclusion The biomaterials studied showed biocompatibility, osteoconductivity, and bioactivity. The Mg concentration in the substituted HA did not stimulate more significant bone formation than HA without this ion.

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.

A new hydroxyapatite-alginate-gelatin biocomposite favor bone regeneration in a critical-sized calvarial defect model.

This study aimed to evaluate the osteogenic potential of hydroxyapatite (HA), Alginate (Alg), and Gelatine (Gel) composite in a critical-size defect model in rats. Twenty-four male rats were divided into three groups: a negative control with no treatment (Control group), a positive control treated with deproteinized bovine bone mineral (DBBM group), and the experimental group treated with the new HA-Alg-Gel composite (HA-Alg-Gel group). A critical size defect (8.5mm) was made in the rat's calvaria, and the bone formation was evaluated by in vivo microcomputed tomography analysis (µCT) after 1, 15, 45, and 90 days. After 90 days, the animals were euthanized and histological and histomorphometric analyses were performed. A higher proportion of mineralized tissue/biomaterial was observed in the DBBM group when compared to the HA-Alg-Gel and Control groups in the µCT analysis during all analysis periods. However, no differences were observed in the mineralized tissue/biomaterial proportion observed on day 1 (immediate postoperative) in comparison to later periods of analysis in all groups. In the histomorphometric analysis, the HA-Alg-Gel and Control groups showed higher bone formation than the DBBM group. Moreover, in histological analysis, five samples of the HA-Alg-Gal group exhibited formed bone spicules adjacent to the graft granules against only two of eight samples in the DBBM group. Both graft materials ensured the maintenance of defect bone thickness, while a tissue thickness reduction was observed in the control group. In conclusion, this study demonstrated the osteoconductive potential of HA-Alg-Gel bone graft by supporting new bone formation around its particles.

A new hydroxyapatite-alginate-gelatin biocomposite favor bone regeneration in a critical-sized calvarial defect model

Abstract This study aimed to evaluate the osteogenic potential of hydroxyapatite (HA), Alginate (Alg), and Gelatine (Gel) composite in a critical-size defect model in rats. Twenty-four male rats were divided into three groups: a negative control with no treatment (Control group), a positive control treated with deproteinized bovine bone mineral (DBBM group), and the experimental group treated with the new HA-Alg-Gel composite (HA-Alg-Gel group). A critical size defect (8.5mm) was made in the rat's calvaria, and the bone formation was evaluated by in vivo microcomputed tomography analysis (µCT) after 1, 15, 45, and 90 days. After 90 days, the animals were euthanized and histological and histomorphometric analyses were performed. A higher proportion of mineralized tissue/biomaterial was observed in the DBBM group when compared to the HA-Alg-Gel and Control groups in the µCT analysis during all analysis periods. However, no differences were observed in the mineralized tissue/biomaterial proportion observed on day 1 (immediate postoperative) in comparison to later periods of analysis in all groups. In the histomorphometric analysis, the HA-Alg-Gel and Control groups showed higher bone formation than the DBBM group. Moreover, in histological analysis, five samples of the HA-Alg-Gal group exhibited formed bone spicules adjacent to the graft granules against only two of eight samples in the DBBM group. Both graft materials ensured the maintenance of defect bone thickness, while a tissue thickness reduction was observed in the control group. In conclusion, this study demonstrated the osteoconductive potential of HA-Alg-Gel bone graft by supporting new bone formation around its particles.

Resumo Este estudo teve como objetivo avaliar o potencial osteogênico de um compósito de hidroxiapatita (HA), alginato (Alg) e gelatina (Gel) em um modelo de defeito de tamanho crítico em ratos. Vinte e quatro ratos machos foram divididos em três grupos: um controle negativo sem tratamento (grupo controle), um controle positivo tratado com osso bovino desproteinizado (grupo DBBM) e o grupo experimental tratado com o novo compósito HA-Alg-Gel (grupo HA-Alg-Gel). Um defeito de tamanho crítico (8,5mm) foi feito na calvária dos ratos, e a formação óssea foi avaliada por análise de microtomografia computadorizada in vivo (µCT) após 1, 15, 45 e 90 dias. Após 90 dias, os animais foram eutanasiados e análises histológicas e histomorfométricas foram realizadas. Uma maior proporção de tecido mineralizado/biomaterial foi observada no grupo DBBM quando comparado aos grupos HA-Alg-Gel e controle na análise de µCT durante todos os períodos de análise. Entretanto, não foram observadas diferenças na proporção tecido mineralizado/biomaterial no dia 1 (pós-operatório imediato) em relação aos períodos posteriores de análise em todos os grupos. Na análise histomorfométrica, os grupos HA-Alg-Gel e controle apresentaram maior formação óssea do que o grupo DBBM. Além disso, na análise histológica, cinco amostras do grupo HA-Alg-Gal exibiram espículas ósseas formadas adjacentes aos grânulos do enxerto contra apenas duas das oito amostras do grupo DBBM. Ambos os materiais de enxerto garantiram a manutenção da espessura óssea do defeito, enquanto uma redução da espessura do tecido foi observada no grupo controle. Em conclusão, este estudo demonstrou o potencial osteocondutor do enxerto ósseo de HA-Alg-Gel, promovendo a formação de osso novo ao redor das suas partículas.

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 Study of Non-critical Bone Defect Repair after Implantation of Magnesium-substituted Hydroxyapatite Microspheres / Estudo histomorfométrico do reparo de defeito ósseo não crítico após implantação de microesferas de hidroxiapatita substituída por magnésio

Abstract Objective The present study aims to analyze histomorphometrically the repair of a non-critical bone defect after implantation of hydroxyapatite (HA) microspheres substituted by magnesium (Mg). Methods Thirty rats were distributed into 3 experimental groups, evaluated at 15 and 45 days postoperatively: HAG (bone defect filled with HA microspheres); HAMgG (bone defect filled with HA microspheres replaced with 1 mol% Mg), and CG (bone defect without implantation of biomaterials). Results After 15 days, the biomaterials filled the entire defect extent, forming a new osteoid matrix between the microspheres. In the CG, this neoformation was restricted to the edges with the deposition of loose connective tissue with reduced thickness. At 45 days, new bone formation filled almost the entire extension of the bone defect in the 3 groups, with statistically significant osteoid deposition in the CG despite the reduced thickness compared with the HAG and HAMgG. The groups with biomaterial implantation displayed a more abundant osteoid matrix than at 15 days. Conclusion The biomaterials studied showed biocompatibility, osteoconductivity, and bioactivity. The Mg concentration in the substituted HA did not stimulate more significant bone formation than HA without this ion.

Resumo Objetivo O presente estudo teve como objetivo fazer uma análise histomorfométrica do reparo de um defeito ósseo não crítico após a implantação de microesferas de hidroxiapatita (HA) com substituição por magnésio (Mg). Métodos Trinta ratos foram distribuídos em 3 grupos experimentais, avaliados aos 15 e 45 dias após a cirurgia: GHA (defeito ósseo preenchido com microesferas de HA); GHAMg (defeito ósseo preenchido com microesferas de HA com substituição por 1 mol% de Mg) e GC (defeito ósseo sem implantação de biomateriais). Resultados Aos 15 dias, evidenciou-se que os biomateriais preencheram toda a extensão do defeito, com neoformação de matriz osteoide de permeio às microesferas. No GC, essa neoformação ficou restrita às bordas, com deposição de tecido conjuntivo frouxo de espessura reduzida. Aos 45 dias, a neoformação óssea preencheu quase toda a extensão do defeito ósseo nos 3 grupos, com deposição osteoide estatisticamente significativa no GC, apesar da espessura reduzida em comparação ao GHA e o GHAMg. Os grupos com implantação de biomaterial apresentaram matriz osteoide mais abundante do que aos 15 dias. Conclusão Os biomateriais estudados apresentaram biocompatibilidade, osteocondutividade e bioatividade. A concentração de Mg na HA com substituição não estimulou a formação óssea mais significativa do que a HA sem este íon.

Experimental protocol for evaluation of biomaterials in an in-vivo silicone implant coverage

ABSTRACT Purpose: To describe an experimental surgical model in rats using a dual-plane technique for evaluation of biomaterials in an in-vivo silicone implant coverage. Methods: This study was developed following the ISO 10993-6 standard. In this study, 40 male Wistar rats weighing between 250 and 350 g were used, distributed into two groups: experimental, biomaterial superimposed on the minimammary prosthesis (MP); and control, MP without implantation of the biomaterial, with eight animals at each biological point: 1, 2, 4, 12, and 26 weeks. Thus, at the end of biological points (1, 2, 4, 12, and 26 weeks; n = 8 animals per week), the tissue specimens achieved were fixed in buffered formalin and stained with hematoxylin-eosin. Results: Macroscopically, throughout the study, no postoperative complications were apparent. In the histological analysis, it was possible to observe the evolution of the inflammatory response, tissue repair, and fibrous capsule during the biological points. Conclusions: The experimental model described in this study proved to be suitable for evaluating the biomaterial used in the coverage of breast silicone implants.

Investimentos do Sistema Único de Saúde do Brasil em vocologia no período de 2008 a 2022 / Investments of the Brazilian Unified Health System in vocology in the period from 2008 to 2022

RESUMO Objetivo Analisar os investimentos do Sistema Único de Saúde do Brasil destinados à vocologia. Métodos Estudo ecológico, de caráter quantitativo com dados públicos, secundários, disponibilizados na plataforma digital DataSUS/TABNet. Os dados referem-se à quantidade e aos valores dos procedimentos da vocologia, apresentados e aprovados durante o período de 2008 a 2022 no Brasil. Após a coleta e análise descritiva dos dados, foram adotados os valores absolutos, relativos, taxas de crescimento e déficit. Resultados No período analisado foram realizados 4.6 milhões de procedimentos realizados a um custo total de R$18.350 milhões. Destes, 2.4 milhões de procedimentos foram aprovados a receberem o pagamento pelas secretarias de saúde dos estados e municípios a um custo total de R$ 10.617 milhões aos cofres públicos. Estes valores repassados representaram uma taxa de crescimento nos investimentos destinados aos procedimentos da vocologia em até 491%, se comparado ao ano de 2008, porém acumulou-se uma taxa de déficit financeiro de até 360% em todo o período estudado. Conclusão Constatou-se que os investimentos públicos destinados à vocologia passaram por crescimento significativo em todos os índices analisados, apesar de não terem sido repassados a totalidade dos valores referentes aos procedimentos realizados.

ABSTRACT Purpose To analyze the investments of the Unified Health System in Brazil destined to vocology. Methods Ecological, quantitative study with public, secondary data, available on the DataSUS/TABNet digital platform. The data refer to the quantity and values of the vocology procedures, presented and approved during the period from 2008 to 2021 in Brazil. After data collection and descriptive analysis, absolute and relative values, growth rates and deficit were adopted. Results In the analyzed period, 4,6 million procedures were carried out at a total cost of R$18,350 million. Of these, 2,4 million procedures were approved to be paid by state and municipal health departments at a total cost of R$10,617 million to public coffers. These transferred values represented a growth rate in investments destined to vocology procedures of up to 491%, if compared to 2008, however, a financial deficit rate of up to 360% was accumulated throughout the studied period. Conclusion It was verified that the public investments destined to vocology had a significant growth in all the indices analyzed, despite not having been passed on the totality of the values referring to the procedures carried out.

Investimentos do Sistema Único de Saúde em avaliação miofuncional do sistema estomatognático / Investments of the Single Health System in myofunctional assessment of the stomatognatic system

Introdução: o sistema estomatognático é responsável por funções inatas e primordiais ao ser humano, como respiração, sucção, deglutição e fonação. O fonoaudiólogo é o profissional qualificado para realizar avaliação, diagnóstico e reabilitação desse sistema. Dessa forma, tais procedimentos são realizados por serviços de fonoaudiologia, e essa produtividade é lançada na plataforma correspondente do Sistema Único de Saúde (SUS) como "avaliação miofuncional do sistema estomatognático". Objetivo: analisar os investimentos do SUS destinados à avaliação miofuncional do sistema estomatognático no Brasil, no período de 2008 a 2021. Metodologia: trata-se de estudo ecológico, de caráter quantitativo, realizado com dados secundários disponibilizados na plataforma DataSUS/TABNet. Os dados coletados se referem a valores apresentados e aprovados para a avaliação miofuncional do sistema estomatognático, no período supracitado, no Brasil. Após a coleta, realizou-se a análise descritiva dos dados, com exposição dos valores absolutos e relativos, das taxas de crescimento e do déficit de repasses dos recursos financeiros. Resultados: no período estudado, foram realizadas 5,4 milhões de avaliações miofuncionais do sistema estomatognático, a um custo total de R$ 21,5 milhões com taxas de crescimento dos investimentos financeiros de até 64,1% ao longo dos anos. Observou-se que, em todo o período estudado, ocorreu déficit de repasses para procedimentos relacionados aos serviços de fonoaudiologia, chegando a taxas de 17464,6% de pagamentos não efetuados. Conclusão: constatou-se que houve aumento dos investimentos financeiros do SUS destinados ao procedimento de avaliação miofuncional. Contudo, foram notados, também, déficits de pagamentos pelas secretarias de saúde, destinados a uma parcela dos procedimentos realizados nos serviços de fonoaudiologia.

Introduction: the stomatognathic system is responsible for innate and primordial functions for human beings, such as breathing, sucking, swallowing and phonation. The speech therapist is the qualified professional to carry out evaluation, diagnosis and rehabilitation of this system. Thus, such procedures are performed by speech therapy services, and this productivity is released on the corresponding platform of the Unified Health System (SUS) as "myofunctional assessment of the stomatognathic system". Objective: to analyze SUS investments for the myofunctional assessment of the stomatognathic system in Brazil, from 2008 to 2021. Methodology: this is an ecological study, of a quantitative nature, carried out with secondary data available on the DataSUS/TABNet platform. The data collected refer to values presented and approved for the myofunctional assessment of the stomatognathic system, in the aforementioned period, in Brazil. After collection, a descriptive analysis of the data was carried out, with exposure of absolute and relative values, growth rates and the deficit in transfers of financial resources. Results: in the studied period, 5.4 million myofunctional assessments of the stomatognathic system were performed, at a total cost of R$ 21.5 million, with growth rates of financial investments of up to 64.1% over the years. It was observed that, throughout the studied period, there was a deficit in transfers for procedures related to speech therapy services, reaching rates of 17464.6% of payments not made. Conclusion: it was found that there was an increase in SUS financial investments for the myofunctional assessment procedure. However, deficits in payments by the health secretariats were also noted, destined for a portion of the procedures performed in the speech-language pathology services.

Morbimortalidade por acidentes de trânsito terrestres na Bahia entre os anos de 2011 e 2021 / Morbidity and mortality from road traffic accidents in Bahia between the years 2011 and 2021

Introdução: os acidentes de trânsito terrestre (ATT) representam um problema de saúde pública de grande relevância, que tem provocado impacto na morbimortalidade da população brasileira. Assim, torna-se premente a busca de soluções que visem a melhorar a segurança no trânsito e reduzir os ATT, que comprometem e oneram diferentes setores da sociedade e a qualidade de vida das vítimas. Objetivo: estimar tendências acerca da morbimortalidade por ATT na Bahia, entre 2011 e 2021. Metodologia: trata-se de um estudo ecológico, quantitativo, descritivo, realizado mediante análise dos dados populacionais do Departamento de Informática do Sistema Único de Saúde (DATASUS) acerca dos indivíduos que sofreram ATT na Bahia, entre 2011 e 2021. Resultados: foram registrados 2.268 óbitos e 102.490 internações, com maior ocorrência na macrorregião de Salvador, com o sexo masculino, cor parda, faixa etária entre 20 e 29 anos, mais frequente entre os motociclistas, seguidos dos pedestres. Observou-se tendência de aumento no número de internações, nos dias de permanência hospitalar e nos valores dos serviços associados, bem como variabilidade do número de óbitos e redução da taxa de mortalidade. As fraturas dos ossos da tíbia e clavícula, do antebraço e fêmur foram os procedimentos cirúrgicos com maior quantidade de internações relacionadas. Conclusão: os dados evidenciaram uma tendência de aumento do número de traumas, lesões, internações, óbitos e custos decorrentes dos ATT. Destarte, almeja-se que os Resultados do presente estudo subsidiem discussões e políticas públicas que intensifiquem as medidas de segurança no trânsito, com vistas a reduzir a incidência dos ATT e suas consequências socioeconômicas.

Introduction: road traffic accidents (RTA) represent a public health problem of great importance, which has had an impact on the morbidity and mortality of Brazilian population. Thus, the search for solutions that aim to improve traffic safety and reduce ATT becomes urgent, which compromise and burden different sectors of society and the quality of life of victims. Objective ­ To estimate trends in morbidity and mortality from RTA in Bahia, between 2011 and 2021. Methodology: this is an ecological, quantitative, descriptive study carried out by analyzing population data from the Department of Informatics of the Unified Health System (DATASUS) about individuals who suffered RTA in Bahia, between 2011 and 2021. Results: there were 2,268 deaths and 102,490 hospitalizations, with the highest occurrence in the macro-region of Salvador, with males, mixed race, aged between 20 and 29 years, more frequent among motorcyclists, followed by pedestrians. There was a trend towards an increase in the number of hospitalizations, in the days of hospital stay and in the values of associated services, as well as variability in the number of deaths and a reduction in the mortality rate. Fractures of the tibia and clavicle, forearm and femur bones were the surgical procedures with the highest number of related hospitalizations. Conclusion: data showed a trend towards an increase in the number of traumas, injuries, hospitalizations, deaths and costs resulting from RTA. Thus, it is hoped that the Results of the present study support discussions and public policies that intensify traffic safety measures, with a view to reducing the incidence of RTA and their socioeconomic consequences.

Influence of the geometry of nanostructured hydroxyapatite and alginate composites in the initial phase of bone repair1.

PURPOSE: To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair. METHODS: Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldner's trichrome. RESULTS: The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect. CONCLUSION: The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.

Influence of the geometry of nanostructured hydroxyapatite and alginate composites in the initial phase of bone repair

Purpose:To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair.Methods:Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldners trichrome.Results:The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect.Conclusion:The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.(AU)

Influence of the geometry of nanostructured hydroxyapatite and alginate composites in the initial phase of bone repair

Abstract Purpose: To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair. Methods: Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldner's trichrome. Results: The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect. Conclusion: The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite.

This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 µm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes.

Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite

ABSTRACT Objective: This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Methods: Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. Results: The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. Conclusion: The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes.

SHEEP AS AN EXPERIMENTAL MODEL FOR BIOMATERIAL IMPLANT EVALUATION

ABSTRACT Objective: Based on a literature review and on our own experience, this study proposes sheep as an experimental model to evaluate the bioactive capacity of bone substitute biomaterials, dental implant systems and orthopedics devices. The literature review covered relevant databases available on the Internet from 1990 until to date, and was supplemented by our own experience. Methods: For its resemblance in size and weight to humans, sheep are quite suitable for use as an experimental model. However, information about their utility as an experimental model is limited. The different stages involving sheep experiments were discussed, including the care during breeding and maintenance of the animals obtaining specimens for laboratory processing, and highlighting the unnecessary euthanasia of animals at the end of study, in accordance to the guidelines of the 3Rs Program. Results: All experiments have been completed without any complications regarding the animals and allowed us to evaluate hypotheses and explain their mechanisms. Conclusion: The sheep is an excellent animal model for evaluation of biomaterial for bone regeneration and dental implant osseointegration. From an ethical point of view, one sheep allows for up to 12 implants per animal, permitting to keep them alive at the end of the experiments. Level of Evidence II, Retrospective Study.

SHEEP AS AN EXPERIMENTAL MODEL FOR BIOMATERIAL IMPLANT EVALUATION.

OBJECTIVE: Based on a literature review and on our own experience, this study proposes sheep as an experimental model to evaluate the bioactive capacity of bone substitute biomaterials, dental implant systems and orthopedics devices. The literature review covered relevant databases available on the Internet from 1990 until to date, and was supplemented by our own experience. METHODS: For its resemblance in size and weight to humans, sheep are quite suitable for use as an experimental model. However, information about their utility as an experimental model is limited. The different stages involving sheep experiments were discussed, including the care during breeding and maintenance of the animals obtaining specimens for laboratory processing, and highlighting the unnecessary euthanasia of animals at the end of study, in accordance to the guidelines of the 3Rs Program. RESULTS: All experiments have been completed without any complications regarding the animals and allowed us to evaluate hypotheses and explain their mechanisms. CONCLUSION: The sheep is an excellent animal model for evaluation of biomaterial for bone regeneration and dental implant osseointegration. From an ethical point of view, one sheep allows for up to 12 implants per animal, permitting to keep them alive at the end of the experiments. Level of Evidence II, Retrospective Study.

Avaliação do potencial osteogênico de matrizes tridimensionais colagênicas aniônicas, reticuladas ou não em glutaraldeído, na regeneração de defeitos críticos, em calvária de rato / Evaluation of the osteogenic potential of three-dimensional arrays collagenic anionic, crosslinked or not in glutaraldehyde, the regeneration of critical defects in rat calvaria

O objetivo deste trabalho foi avaliar histomorfometricamente, por microscopia de luz comum, o potencial osteogênico de matrizes colagênicas aniônicas, reticuladas ou não em glutaraldeído, implantadas em defeitos ósseos críticos, em calvária de ratos. Foram utilizados 86 ratos divididos aleatoriamente para compor quatro grupos: GI - matriz colagênica aniônica com 24h de hidrólise e 15min de reticulação em GA 0,05 por cento (MCAHGA); GII - matriz colagênica aniônica com 24h de hidrólise (MCA); GIII - matriz colagênica neutra, controle positivo (MCN) e GIV - defeito ósseo vazio, sem implantação de biomaterial, preenchido por coágulo sanguíneo, controle negativo. Os animais foram avaliados nos pontos biológicos de 15, 45, 90 e 120 dias. Os resultados evidenciaram que os biomateriais implantados nos grupos I e II foram biocompatíveis, embora tenham desencadeado inflamação crônica granulomatosa discreta e regressiva. Estas matrizes apresentaram velocidade de biodegradação compatível com a neoformação óssea, a qual se mostrou associada a angiogênese no interior das matrizes, em todos os pontos biológicos. No GIII, a fragmentação e biodegradação mostraram-se acentuadas, pela ausência de tratamento químico do colágeno. A neomineralização evidenciada nos grupos I e II apresentou aumento estatisticamente significante ao longo dos tempos. O percentual de mineralização do Gil (87 por cento) foi estatisticamente diferente daquele encontrado no GI (66 por cento). Ao compararmos estes percentuais com a mineralização observada no GIV, notam-se diferenças muito significantes. Neste último, assim como no GIII, a neoformação óssea esteve limitada às bordas do defeito com fibrose na área seccional do defeito. Conclui-se que as matrizes colagênicas aniônicas apresentaram potencial osteogênico mais evidente nas matrizes sem reticulação em glutaraldeído. Estas matrizes apresentam grande potencial de aplicabilidade clínica, nas terapias regenerativas ósseas.

Histomorphometric analysis of tissue responses to bioactive glass implants in critical defects in rat calvaria.

The aim of this study was to evaluate the osteogenic behavior of two chemically similar bioactive glass products (Biogranand Perioglas) implanted in critical bone defects in rat calvaria. Thirty-six transfixed bone defects of 8 mm diameter were made surgically in adult male Wistar rats. The animals were distributed equally into three groups: Biogran (GI), Perioglas (GII) and without implant material (control; GIII). The morphology and composition of both bioactive glasses were analyzed by scanning electron microscopy and energy-dispersive spectrometry. Tissue specimens were analyzed at the biological time points of 15, 30 and 60 days by optical microscopy and morphometry, demonstrating biocompatibility for the tested materials with moderate chronic inflammation involving their particles. Bone neoformation resulted only as a reparative reaction to an intentionally produced defect and was limited to the defect's edges. No statistically significant differences among the groups were observed. At the scar interstice, abundant deposits of collagenous fibers enveloping the particles were noted. The present results indicated that the bioactive glasses, under the experimental conditions analyzed, did not show osteogenic behavior.