Research progress on the mechanical compatibility of restorative materials with dental tissue / 口腔疾病防治

@#As the main means of mastication, teeth can withstand countless functional contacts. The mechanical properties of teeth are closely related to their tissue structure. Enamel and dentin have a high hardness and modulus of elasticity, and their graded structure allows them to withstand bite forces without being susceptible to fracture. When tooth tissue is defective, full crown restoration is often needed to restore the normal shape and function of the tooth. Metal materials, ceramic materials, and polyetheretherketone (PEEK) materials are commonly used for crown restoration. Metal materials have certain disadvantages in terms of aesthetics and are relatively rarely used in clinical practice. Ceramic materials with different compositions exhibit differences in performance and aesthetics, but their elastic modulus and hardness are much higher than those of dental tissue, resulting in mismatching mechanical properties. In contrast, the elastic modulus of PEEK is lower than that of tooth tissue and similar to that of bone tissue, but its properties can be improved by fiber reinforcement. Notably, when the mechanical properties of a restoration material and tooth tissue are not fully matched, the interface between them often forms a potential weak link, which ultimately affects the stability and long-term effect of the restoration. This article introduces the mechanical properties and corresponding structural characteristics of enamel and dentin. On this basis, the advantages and limitations of existing restoration materials are analyzed, and the possibility of biomimetic design of full crowns is further explored.

Aumento do Rebordo Alveolar com Enxerto em Bloco Impresso Personalizado: Relato de Caso / Alveolar ridge augmentation with custom 3D-printed block graft: Case report

A utilização da tecnologia CAD/CAM (computer aided design/computer aided manufacturing) e 3D (tridimensional) para reconstruções alveolares na implantodontia permite o planejamento pré-operatório detalhado, o design do resultado desejado do enxerto e a avaliação virtual do resultado em relação à reconstrução protética. Este trabalho objetiva detalhar a técnica cirúrgica de enxerto ósseo sintético confeccionado por meio dessa tecnologia, seguido da instalação de implantes osseointegráveis e reabilitação protética em um defeito ósseo na mandíbula. Paciente masculino, 22 anos, compareceu à clínica por avulsão dos elementos 32, 31, 41 e 42 com significativa perda óssea vertical de rebordo alveolar. Devido à extensa perda óssea, realizou-se enxerto em bloco prototipado impresso. O escaneamento intraoral e os arquivos de imagem gerados foram enviados ao centro de planejamento virtual. Primeiramente, foi realizada a cirurgia para instalação do enxerto em bloco. Após o período de cicatrização, foi realizada cirurgia para instalação de dois implantes osseointegráveis. Esperado o período de três meses a partir da instalação dos implantes, foi realizada a confecção de próteses provisórias fixas sobre implantes a fim de realizar o condicionamento dos tecidos moles peri-implantares e o carregamento progressivo dos implantes. O aumento do rebordo alveolar através do uso de enxerto em bloco impresso personalizado apresentou-se como uma técnica com inúmeras vantagens, por não necessitar de sítio doador, reduzir tempo cirúrgico e apresentar perfeita adaptação do bloco ao defeito ósseo, resultando em menor morbidade pós-operatória. Essa técnica é uma indicação para casos de defeitos ósseos severos, visando a otimizar o resultado e a propiciar menor desconforto ao paciente.

The use of the technology CAD/CAM (computer aided design/computer aided manufacturing) and 3D (three dimensional) to alveolar reconstructions in implant dentistry allows detailed preoperative planning, the design of the desired grafting result, and the virtual evaluation of the result in relation to the prosthetic reconstruction. This paper aims to details the synthetic bone graft made through this technology, followed by the installation of osseointegrated implants and prosthetic rehabilitation in a bone imperfection in the jaw. A 22-year-old man attended the clinic due to a tooth avulsion of the four lower incisors with significant vertical bone loss of alveolar ridge. Because of the extensive bone loss, it was made a prototyped printed block graft. The intraoral scan and the generated image files were sent to the virtual planning center. First, it was necessary a surgery to install the block graft. After the healing process, it was made a surgery to put two osseointegrated implants. Three months later, temporary fixed prostheses on implants were made to conditioning the peri-implant soft tissues and the progressive loading of the implants. The increase of the alveolar ridge using personalized printed block graft was presented as a technique with numerous advantages, since it does not require a donor site, reduces the surgical time and presents perfect adaptation of the block to the bone imperfection, resulting in a less postoperative morbidity. This technique is indicated to cases of severe bone imperfections, aims to optimize results, and provide less discomfort to the patient.

Anti-erosion effect of an experimental varnish on eroded dentin

Abstract This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Resumo Este estudo in vitro avaliou o efeito de um verniz experimental contendo 20% de nano-hidroxiapatita (nHAP) associado a 5% de cloreto estanoso (SnCl2) contra o desgaste erosivo-abrasivo da dentina bovina. As amostras de dentina cervical bovina foram pré-erodificadas (0,3% de ácido cítrico, pH 2,6 durante 10 minutos) e aleatorizadas em 4 grupos (n=10): Grupo controle - verniz experimental sem ingrediente ativo (GC); verniz experimental contendo 20% nHAP (GnH); verniz experimental contendo 5% SnCl2 (24.800 ppm Sn2+) (GSn); verniz experimental contendo 20% nHAP associado a 5% SnCl2 (18.300 ppm Sn2+) (GnHSn). Após a aplicação dos materiais, os desafios erosivo-abrasivos foram realizados durante cinco dias. Perda de dentina erosiva e análise do padrão de obliteração dentinária foram realizadas por microscopia laser confocal 3D. Foi realizado o teste ANOVA/Bonferroni unidireccional para analisar os dados (α=0,05). Os grupos experimentais GSn e GnHSn apresentaram maior eficácia na prevenção do desgaste erosivo quando comparados com os outros grupos (p<0,05). Não houve diferença estatisticamente significativa entre os grupos GSn e GnHSn (p = 0,731) na perda de dentina da estrutura dentária. Relativamente à quantidade de túbulos dentinários abertos, a maior quantidade de túbulos dentinários obstruídos foi demonstrada em GSn e GnHSn (p < 0,05) quando comparada com os outros grupos. Entre GSn e GnHSn, não houve diferença significativa (p = 0,952) na quantidade de túbulos dentinários fechados na dentina. Os vernizes experimentais contendo 5% de SnCl2 associados ou não a 20% de nHAP mostraram ser uma estratégia promissora na prevenção do desgaste erosivo-abrasivo da dentina. Além disso, o GnHSn conseguiu obliterar os túbulos dentinários.

Suckermouth catfish bone extract as bone graft raw material for bone-healing promotes bone growth in bone loss / Extrato de osso de bagre como material de reparo promove o crescimento ósseo em perda óssea

Objective: This study aimed to evaluate the properties of suckermouth catfish bone extract, which allows it to be adopted as a raw material for bone graft following its graft in an artificial defect of a rat model. Material and Methods: Hydroxyapatite (HA) from suckermouth catfish bone extract was characterized using Fourier-transform infrared spectroscopy (FTIR), and its toxicity was evaluated by Brine Shrimp Lethality Test (BSLT). This material was grafted on artificial defects in rats' femoral bones, which were observed immunologically by Enzyme-linked immunosorbent assay (ELISA) after one week and four weeks, and radiographically in the second week, and histologically in the second and fourth weeks. Results: FTIR shows that this material consists of phosphate, hydroxyl, and carbonate groups, while the BSLT results show that this material is not toxic. Observations by ELISA showed an increase in the expression of Tumor necrosis factor alpha (TNF-α) in defects with HA in the fourth week. Radiographically the defect did not show closure in the second week. In contrast, histological analysis showed a better bone healing process in the defect, which was applied with the HA of the suckermouth catfish bone. Conclusion: The HA extracted from the suckermouth catfish bone has beneficial properties as an alternative to bone graft raw material and, more investigated needed to support this biomaterial to be used in the treatment of bone loss (AU)

Objetivo: Avaliar as propriedades do extrato de osso de bagre, que permitem sua adoção como material bruto para enxerto ósseo, em um defeito ósseo artificial em ratos. Material e Métodos: A hidroxiapatita (HA) do extrato de osso de bagre foi caracterizada usando espectroscopia infravermelha por transformada de Fourier (FTIR), e sua toxicidade foi avaliada pelo Teste de Letalidade do Camarão de Sal (BSLT). Esse material foi enxertado em defeitos artificiais nos ossos femorais de ratos. Análise imunológica por meio do ensaio imunoenzimático (ELISA) foi realizada uma e quatro semanas após a colocação dos enxertos. Análises radiográficas foram feitas na segunda semana e histológica na segunda e quarta semanas. Resultados: A FTIR mostrou que esse material é composto por grupos de fosfato, hidroxila e carbonato, enquanto os resultados do BSLT mostraram que esse material não é tóxico. As observações pelo ELISA mostraram um aumento na expressão do fator de necrose tumoral alfa (TNF-α) nos defeitos com HA na quarta semana. Radiograficamente, o defeito não apresentou fechamento na segunda semana. Em contraste, a análise histológica mostrou um melhor processo de cicatrização óssea no defeito que foi aplicado com a HA do osso de bagre. Conclusão: A HA extraída do osso de bagre possui propriedades benéficas como alternativa ao material bruto para enxerto ósseo, sendo necessárias mais investigações para apoiar esse biomaterial a ser usado no tratamento da perda óssea.(AU)

Expression of Stro-1, Runx-2, Osterix, and Alp in Alveolar Bone Regeneration Process Following the Administration of Hydroxyapatite Gypsum Puger (HAGP) Scaffold

@#Introduction: Tooth extraction before denture placement could result in trauma and damage to up to 50% of the alveolar bone, inducing bone resorption, and affecting the patient’s quality of life. Hydroxyapatite Gypsum Puger (HAGP) can be used as an alternative to bone graft material which degrades slowly, affecting the proliferation and activity of cells that are responsible for bone tissue engineering. This study aimed to analyze the regeneration mechanism of alveolar bone by administering the HAGP scaffold and observing the Stro-1, Runx-2, Osterix, and ALP expression. Methods: Laboratory experimental research was conducted and we used 150-355µm HAGP scaffold particles, applied in vivo inside alveolar sockets of the rats for 7, 14, and 28 days, followed by immunohistochemical examination of Stro-1, Runx-2, Osterix, and ALP expressions. Results: The HAGP scaffold group showed that the Stro-1 expression was significantly higher than the K(-) group, and the Runx-2 expression increased on day 7 and decreased on day 28 in the HAGP and K(-) groups. Osterix expression increased from day 7, 14, to day 28. The high expression of Osterix on day 28 means it took over the Runx-2 function. In ALP there was a significant increase on day 7. ALP expression was a sign of early osteoblast differentiation and production by cells, this extracellular matrix mineralization is an indicator of the osteogenic process. Conclusion: Alveolar bone regeneration mechanism in rats revealed that the expression of Stro-1, Runx-2, Osterix, and ALP was higher in the HAGP scaffold group compared to the control group on days 7,14, and 28.

Preparation and properties of silica/hydroxyapatite whiskers porous ceramics scaffold / 中国修复重建外科杂志

OBJECTIVE@#To investigate the preparation and properties of the novel silica (SiO 2)/hydroxyapatite (HAP) whiskers porous ceramics scaffold.@*METHODS@#The HAP whiskers were modified by the SiO 2 microspheres using the Stöber method. Three types of SiO 2/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO 2/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO 2/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics.@*RESULTS@#The SiO 2 microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO 2/HAP whiskers, the amorphous SiO 2 microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO 2/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO 2/HAP whisker porous ceramic was the highest. The SiO 2 microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO 2 microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity.@*CONCLUSION@#SiO 2/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.

Biocomponents Based on Hydroxiapatite: Influence of Sterilization on the Mechanical Resistance / Biocomponentes à base de hidroxiapatita: Influência da esterilização na resistência mecânica

Abstract Objective This study aimed to evaluate the influence of sterilization on the compressive and flexural mechanical strength of hydroxyapatite-based biocomponents obtained through freeze-dried bovine bone, and its association with chitosan. Methods Freeze-dried bovine bone was processed into 100 μm particles and mixed with 50% of its weight in chitosan. The mixture was packed in metallic molds for preparing the specimens, and sterilized at 127°C using an autoclave for subsequent experimentation. The specimens were subjected to compression and flexion tests following norm 5833 of the International Organization for Standardization (ISO), with 6 × 12 mm cylindrical blocks (for compression tests) and 75 × 10 × 3.3 mm plates (for flexion tests) as samples. The samples were divided into four groups of 20 specimens each, with 10 for compression and 10 for flexion tests. Three groups were sterilized (autoclave, gamma rays, and ethylene oxide), whereas the fourth group (control) was not. The mechanical tests obtained from the different sterilization processes were compared using analysis of variance (ANOVA, p< 0.05), followed by the Tukey multiple comparison test of means, with a 95% confidence interval. Results The specimens presented mean compressive strengths of 10.25 MPa for the control group and 3.67 MPa, 9.65 MPa, and 9.16 MPa after ethylene oxide, gamma ray, and autoclave sterilization, respectively. Flexion test results showed an average resistance of 0.40 MPa in the control group, and 0.15 MPa, 0.17 MPa, and 0.30 MPa after ethylene oxide, gamma ray, and autoclave sterilization, respectively. There were statistically significant differences observed in the maximum compression of the ethylene oxide-sterilized group compared with that of the control group (p= 0.0002), gamma ray-sterilized (p= 0.0003), and the autoclaved (p= 0.0006) groups. There was a statistically significant difference in maximum flexion of the specimens sterilized by gamma rays when compared with the control group (p= 0.0245). However, low flexural strengths were observed in all specimens. Conclusion The autoclave sterilization group did not result in statistically significant differences in either compression or flexion strength tests. Thus, the autoclave proved to be the best sterilization option for the hydroxyapatite-based biocomponents in this study.

Resumo Objetivo O objetivo deste estudo foi avaliar a influência da esterilização na resistência mecânica à compressão e flexão de biocomponentes à base de hidroxiapatita obtida a partir de osso bovino liofilizado e sua associação com quitosana. Métodos O osso bovino liofilizado foi processado em partículas de 100 μm e misturado à quitosana em proporção de 50% de seu peso. A mistura foi acondicionada em moldes metálicos para preparo dos espécimes e esterilizada a 127°C em autoclave para posterior experimentação. Os espécimes foram submetidos a ensaios de compressão e flexão seguindo a norma 5833 da International Organization for Standardization (ISO); os espécimes eram blocos cilíndricos de 6 × 12 mm (para ensaios de compressão) e placas de 75 × 10 × 3,3 mm (para ensaios de flexão). As amostras foram divididas em quatro grupos de 20 espécimes cada, sendo 10 para ensaios de compressão e 10 para ensaios de flexão. Três grupos foram esterilizados (por autoclavagem, raios gama e óxido de etileno), enquanto o quarto grupo (controle) não foi. Os testes mecânicos obtidos nos diferentes processos de esterilização foram comparados por análise de variância (ANOVA, p< 0,05) seguido pelo teste de comparação múltipla de médias de Tukey, com intervalo de confiança de 95%. Resultados Os espécimes apresentaram resistências médias à compressão de 10,25 MPa para o grupo de controle e 3,67 MPa, 9,65 MPa e 9,16 MPa após esterilização com óxido de etileno, raios gama e autoclavagem, respectivamente. Os resultados do teste de flexão mostraram uma resistência média de 0,40 MPa no grupo de controle, e 0,15 MPa, 0,17 MPa e 0,30 MPa após esterilização com óxido de etileno, raios gama e autoclavagem, respectivamente. A compressão máxima observada no grupo esterilizado com óxido de etileno foi estatisticamente diferente à obtida no grupo de controle (p= 0,0002), esterilizado com raios gama (p= 0,0003) e autoclavado (p= 0,0006). A flexão máxima dos espécimes esterilizados com raios gama foi estatisticamente diferente à observada no grupo de controle (p= 0,0245). No entanto, a resistência à flexão foi baixa em todos os espécimes. Conclusão A esterilização em autoclave não foi associada a diferenças estatisticamente significativas nos testes de compressão ou flexão. Assim, a autoclave foi a melhor opção de esterilização para os biocomponentes à base de hidroxiapatita neste estudo.

Fracture healing, the diamond concept under the scope: Hydroxyapatite and the hexagon / Consolidación de fractura, una mirada al concepto diamante: Hidroxiapatita y el hexágono

Abstract Bone healing after a fracture has many intercalated steps that depend on the host, type of injury, and often the orthopedist. The diamond concept since 2007 has outlined 4 main facets that have to be considered as a model by the treating surgeon at the time of injury and when nonunion develops: osteogenic cells, osteoconductive scaffolds, osteoinduction, and the biomechanical environment. All of these foment fracture healing in optimal circumstances. Yet, this work proposes other facets, such as osteoimmunology and vascularity, to be considered as well in the model. These are as important as the original four, though their correlation to the original work has been less noted until more recent literature. The mindset of the orthopedist must thoroughly analyze all these facets and many more when dealing with nonunion. This work presents, probably the most sig nificant ones, parting from the original 4-corner diamond model and expanding it to a more representative hexagon integrated model. Metaphorically, just like the strongest inorganic constituent of the bone: hydroxyapatite.

Resumen Hay múltiples pasos intercalados en la consolidación de la fractura que dependen del paciente, el tipo de fractura y frecuentemente del ortopedista. Desde su introducción en el año 2007, el concepto del diamante ha delineado 4 facetas o aristas principales que se han de tener en cuenta por el ortopedista en el momento de la lesión y cuando la no-unión de fractura ocurre: células osteogénicas, matrices osteocunductivas, osteoinducción, y el ambiente biomecánico. Otras facetas para tener en cuenta, no menos importantes, son la osteoimmunología y la vascularidad. Estas son tan importantes como las 4 facetas originales, pero la correlación entre las mismas ha sido poco notada o integrada hasta ahora. El ortopedista tratante debe analizar todas ellas en profundidad, especialmente cuando se trata de una no-unión. Este trabajo presenta las más significantes, partiendo del modelo original del diamante de 4 facetas hacia uno más representativo e integrado como el hexágono. Metafóricamente, como el elemento inorgánico más abundante y fuerte en el hueso: la hidroxiapatita.

Hydroxyapatite and Biopolymer Composites with Promising Biomedical Applications

ABSTRACT The purpose of tissue engineering (regenerative medicine) is to develop materials that replace human tissue, having as main characteristics' biodegradability, biocompatibility, no toxicity, osteoconductivity, which lead to cell maturation and proliferation. Due to the importance of the development of this type of materials, several researchers have used biopolymers and calcium phosphate salts (hydroxyapatite) as composites to be used in this area as drug releases, scaffolds, implants, among others. Different biopolymers can be suitable for this type of application, in this work we have described the most widely used biopolymers for biomedical purposes, such as alginate, collagen, gellan gum, chitosan, and polylactic acid, in addition to a detailed description of hydroxyapatite, biopolymers, as well as biopolymer/hydroxyapatite composites, to highlight their potential and the most relevant characteristics of these materials.

Biomimetic of hydroxyapatite with Tridax procumbens leaf extract and investigation of antibiofilm potential in Staphylococcus aureus and Escherichia coli

In the last few decades, hydroxyapatite (HA) has become one of the most highly prized biominerals in the biomedical industry for orthopedic and dental applications. The focus of this research was to synthesize biomimetic HA from Tridax procumbens (TP) leaf extract and investigate their antibiofilm properties. The HA was made using the sol-gel method and the HA-TP biocomposite was made by precipitation method. The d.nm size of HA and HA-TP biocomposite was determined as 193.28 and 258.14 d.nm, respectively. The zeta potential of HA and HA-TP biocomposite was determined as ?21.2 and ?18.3 mV, respectively, and found highly stable. The FTIR study revealed that phytochemicals of TP were successfully impregnated into HA-TP biocomposite. The HA and HA-TP biocomposite were found spherical and agglomerated from SEM analysis. In HR-TEM analysis, the average diameter of the HA and HA-TP biocomposite were 16.57 – 64.22 nm and 51.71 – 138.68 nm, respectively. According to the EDX analysis, HA is primarily composed of calcium, oxygen, and phosphate, whereas, HA-TP biocomposite is primarily composed of calcium, phosphate, oxygen, and carbon. In the antioxidant assay, the IC50 value (concentration required to scavenge 50% of free radicals) of HA-TP biocomposite was determined as 156.69 ± 14.02 and 180.21 ± 12.84 µg/mL in DPPH and ABTS free radical scavenging assays, respectively. The MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) of as-synthesized HA-TP biocomposite against Staphylococcus aureus – ATCC 13565 and Escherichia coli – MTCC 41 were observed as 181.09 ± 21.47 and 317.30 ± 41.03, and 157.59 ± 32.18 and 264.03 ± 21.58 µg/mL, respectively. The as-synthesized HA-TP biocomposite has detrimentally affected the biofilm formation of both the tested bacteria S. aureus – ATCC 13565 and E. coli – MTCC 41. The study concluded that the as-synthesized HA-TP biocomposite could be highly helpful in the biomedical field for alleviating oxidative-stress-related disorders and inhibiting microbial biofilm formation.

Tendinitis cálcica atraumática de tendón extensor común del dedo medio: un caso infrecuente de dolor metacarpofalángico / Atraumatic calcium tendonitis of common extensor tendon of the middle finger: a rare case of metacarpophalangeal pain

Calcific tendinitis is a pathology characterized by the deposits of periarticular hydroxyapatite. Its pathophysiology is not completely known. It is clinically characterized by important inflammatory changes with incapacitating pain. It most commonly affects the shoulder joint and it rarely affects the hand and wrist. Given the unusual nature of this localization, we present the clinical case of a woman who developed calcific tendinitis of the third metacarpophalangeal muscle. We present the clinical evolution of the case, the treatments carried out, and a review of the literature related to this unusual localization of calcific tendinitis.

Evaluation of biphasic hydroxapatite and ?-tricalcium phosphate as a bone graft material in the treatment of periodontal vertical bony defects – A clinical and digital radiological measurement study

Aims and Objective: The present study aimed to evaluate 2 bone graft materials, that is, biphasic hydroxyapatite and ??tricalcium phosphate, in the treatment of periodontal vertical bony defects. In term of attachment level, probing depth and radiographic bone level changes. Also, a new digital method of radiographic assessment was used for measurement of vertical bone defect. Material and Methods: Ten subjects with periodontitis and having two or more vertical bony defects were enrolled in the study. Patients were classified randomly into 2 groups. Group I consisted of the experimental site where defect was filled with biphasic hydroxyapatite and ??tricalcium phosphate graft and Group II consisted of control site where only the open flap debridement (OFD) was carried out. Clinical parameters were evaluated at baseline, 3 and 6 months; Radiographs were taken at baseline and 6 months after surgery. Results: Overall, by the end of 6 months, biphasic hydroxyapatite and ??tricalcium phosphate and OFD treatment groups exhibited a significant reduction in probing depth almost by 75% and gain in clinical attachment level at follow?up. In the biphasic hydroxyapatite and ??tricalcium phosphate group, radiographic bone level gain appeared to be greater than in the OFD group. Conclusion: In the present study, biphasic hydroxyapatite and ??tricalcium phosphate have shown promising results and have showed reduction in probing depth, a resolution of osseous defects and gain in clinical attachment level when compared to open flap debridement.

Synthesis, characterization, and evaluation of nano-hydroxyapatite based experimental calcium silicate cement as a root repair material / Síntesis, caracterización y evaluación de cemento experimental de silicato de calcio a base de nanohidroxiapatita como material de reparación radicular

Introduction: This study aimed to prepare a new root repair material including Portland cement, bismuth oxide, and nano-hydroxyapatite and analyze its physicochemical properties and its effects on the proliferation and differentiation of human dental pulp stem cells (hDPSCs). Material and Methods: Bismuth oxide as a radiopaque component and nano-hydroxyapatite particles were added to white Portland cement at 20% and 5% weight ratio, respectively. Characterization of the prepared cement was done using conventional methods. To examine the bioactivity of this new material, atomic absorption spectroscopy (AAS) was used for the investigation of the rate of calcium ions dissolution in simulated body fluid media. The viability of hDPSCs was assessed by an MTT assay after 1, 3 and 7 days. The odontogenic potential of this substance was evaluated by measuring alkaline phosphatase activity and alizarin red S staining. Results: Based on the bioactivity results, the cement presented high bio-activity, corroborating sufficiently with the calcium release patterns. The cell viability was significantly increased in new root repair material containing hydroxyapatite nanoparticles after 3 and 7 days (p<0.05). Conclusion: Moreover, alkaline phosphatase activity increased over 7 days in all experimental groups. The new cement containing nano-hydroxyapatite particles could be a good root repair material.

Objetivo: Este estudio tuvo como objetivo preparar un nuevo material de reparación de raíces que incluye cemento Portland, óxido de bismuto y nano-hidroxiapatita y analizar sus propiedades fisicoquímicas y sus efectos sobre la proliferación y diferenciación de células madre de pulpa dental humana. Material y Métodos: El óxido de bismuto como compo-nente radiopaco y las partículas de nano-hidroxiapatita se agregaron al cemento Portland blanco en una proporción en peso del 20 % y el 5 %, respectivamente. La caracterización del cemento preparado se realizó utilizando métodos con-vencionales. Para examinar la bioactividad de este nuevo material, se utilizó la espectroscopia de absorción atómica para investigar la velocidad de disolución de los iones de calcio en medio fluido corporal simulado. La viabilidad de las células madre de pulpa dental humana se evaluó mediante un ensayo MTT después de 1, 3 y 7 días. El potencial odontogénico de esta sustancia se evaluó midiendo la actividad de la fosfatasa alcalina y la tinción con rojo de alizarina S.Resultados: Con base en los resultados de bioactividad, el cemento presentó alta bioactividad, corroborando suficientemente con los patrones de liberación de calcio. La viabilidad celular aumentó significativamente en el nuevo material de reparación de raíces que contenía nanopartículas de hidroxiapatita después de 3 y 7 días (p<0,05). Conclusión: Además, la actividad de la fosfatasa alcalina aumentó durante 7 días en todos los grupos experimentales. El nuevo cemento que contiene partículas de nanohidroxiapatita podría ser un buen material de reparación radicular.

Study on the remineralization of demineralized enamel surfaces with glycine-guided carboxymethyl chitosan/amorphous calcium phosphate / 口腔疾病防治

Objective@#To explore effect on the remineralization of demineralized enamel surfaces with glycine-guided carboxymethyl chitosan (CMC)/amorphous calcium phosphate (ACP).@*Methods@# Remineralized solultion at different stages were prepared: ①reactive CMC/ACP (CMC/ACP nanoparticles treated with NaClO), ②reactive CMC/ACP+glycine; transmission electron microscopy was used to detect the morphology of the remineralized solution particles. Twenty teeth were randomly divided into two groups: group A and group B. Reactive CMC/ACP was applied to the enamel surface of group A and group B was treated with reactive CMC/ACP remineralization solution containing glycine. Scanning electron microscopy was used to detect the enamel surface morphology before and after remineralization, and nanoindentation was used to detect the mechanical strength (including nanoindentation depth, hardness and elastic modulus) of the enamel surface.@*Results@#Under a transmission electron microscope, the particles in the reactive CMC/ACP remineralization solution were smooth, and the increase in particle size was approximately 100-300 nm. After the addition of glycine, the particles in the reactive CMC/ACP remineralization solution particles showed a linear ordered arrangement, and microcrystals were formed in the solution 15 min later, with a crystal length of approximately 5-15 μm. Remineralization in group A was granular and heterogeneous. In group B, the crystal morphology of the demineralized enamel was homogeneous and ordered, similar to that of natural enamel. The nanoindentation depth of group B after remineralization was smaller than that of group A, and it was closest to that of natural enamel, there was no significant difference between group B and natural enamel in terms of the hardness and elastic modulus of the enamel surface after remineralization.@*Conclusion@# CMC/ACP nanoparticles treated with NaClO can rapidly and specifically form directional and ordered remineralization on the enamel surface of a model of glycine-guided rapid remineralization of enamel caries. The surface structure of remineralized enamel is similar to that of natural enamel in terms of nanoindentation depth, hardness and elastic modulus.

The osteogenic niche-targeted arsenic nanoparticles prevent colonization of disseminated breast tumor cells in the bone

Up to 70% of patients with late-stage breast cancer have bone metastasis. Current treatment regimens for breast cancer bone metastasis are palliative with no therapeutic cure. Disseminated tumor cells (DTCs) colonize inside the osteogenic niches in the early stage of bone metastasis. Drug delivery into osteogenic niches to inhibit DTC colonization can prevent bone metastasis from entering its late stage and therefore cure bone metastasis. Here, we constructed a 50% DSS6 peptide conjugated nanoparticle to target the osteogenic niche. The osteogenic niche was always located at the endosteum with immature hydroxyapatite. Arsenic-manganese nanocrystals (around 14 nm) were loaded in osteogenic niche-targeted PEG-PLGA nanoparticles with an acidic environment-triggered arsenic release. Arsenic formulations greatly reduced 4T1 cell adhesion to mesenchymal stem cells (MSCs)/preosteoblasts (pre-OBs) and osteogenic differentiation of osteoblastic cells. Arsenic formulations also prevented tumor cell colonization and dormancy via altering the direct interaction between 4T1 cells and MSCs/pre-OBs. The chemotactic migration of 4T1 cells toward osteogenic cells was blocked by arsenic in mimic 3D osteogenic niche. Systemic administration of osteogenic niche-targeted arsenic nanoparticles significantly extended the survival of mice with 4T1 syngeneic bone metastasis. Our findings provide an effective approach for osteogenic niche-specific drug delivery and suggest that bone metastasis can be effectively inhibited by blockage of tumor cell colonization in the bone microenvironment.

Preparation and physicochemical properties of PVA/HA composite microspheres for embolization / 国际生物医学工程杂志

Objective:To prepare polyvinyl alcohol (PVA) and hydroxyapatite (HA) composite embolization microspheres and investigate their physicochemical properties.Methods:PVA/HA composite embolization microspheres were prepared by reverse suspension polymerization, using PVA and HA as dispersed phases, liquid paraffin containing sorbitan fatty acid ester as the continuous phase, and glutaraldehyde as the cross-linking agent. The morphology, particle size distribution, and microscopic morphology of PVA/HA composite embolization microspheres were observed by optical microscopy and scanning electron microscopy. The chemical structure of PVA/HA composite embolization microspheres and the elasticity, drug loading, and drug release properties of PVA/HA composite bolus microspheres were characterized by Fourier infrared spectroscopy.Results:The PVA/HA composite embolization microspheres were internal, porous round spheres with a particle size distribution of 50-300 μm. The elastic properties of PVA/HA composite embolization microspheres were(13.6±0.145) kPa, which was 2.28 times that of PVA microspheres, and the drug loading capacity and encapsulation efficiency were (76.80±1.22) mg/g and (38.4±12.7)%, respectively. The maximum cumulative release rate of the microspheres within 7 days was (7.37±0.101)%, and the maximum cumulative release was (256.2±9.8) μg.Conclusions:PVA/HA composite embolization microspheres have good mechanical properties and drug-loading and drug-releasing properties, which provide an important reference for their use as medical devices.

Study on the inhibition and remineralization of enamel demineralization by polydopamine in vitro / 口腔疾病防治

Objective@#To investigate the inhibitory effect of polydopamine (PDA) on enamel demineralization in isolated teeth and the induction of hydroxyapatite (HA) production on the surface of demineralized enamel to provide a novel protocol for the prevention and treatment of enamel demineralization. @*Methods@#Twenty isolated bovine teeth were cut into 20 enamel slices and randomly divided into an experimental group and a control group, with 10 slices in each group. The enamel slices in the experimental group were immersed in 2 mg/mL freshly prepared dopamine solution and incubated for 24 hours at room temperature in the dark to prepare the PDA coating, while the control group was left untreated. Then, the isolated bovine teeth, with and without PDA coating, were immersed in artificial demineralization solution at 37 °C for 3 days, followed by 7 days in simulated body fluid (SBF), and the immersion solution was changed daily. The surface morphology of enamel was observed by scanning electron microscopy (SEM), the calcium/phosphorus ratio of the enamel surface was analyzed by energy dispersive spectroscopy (EDS), and the characteristic functional groups in enamel deposits were analyzed by Fourier transform infrared spectroscopy (FTIR).@* Results@#Compared with the control group, the number of demineralized pores produced after 3 d of enamel demineralization with polydopamine coating was less, and the diameter was smaller. EDS elemental analysis showed that the Ca/P ratio after enamel demineralization was 2.37 in the experimental group, which was smaller than the 2.53 ratio in the control group. In the remineralization experiment, after 7 days of remineralization of PDA coated enamel in the experimental group, lamellar grains were produced on the enamel surface, and the growth showed obvious directionality, growth regularity and uniform arrangement. In the control group, the surface of enamel was flocculent mineral deposit, and the crystallinity was poor. The FTIR results proved that the enamel surface deposit of PDA-coated enamel was HA after 7 d of remineralization. @*Conclusion @#PDA can affect the nucleation process of HA and promote the production of HA on the surface of demineralized enamel.

Análise fatorial da adsorção de cobre em solução aquosa por hidroxiapatita / Factor analysis of copper adsorption in aqueous solution by hydroxyapatite

RESUMO O cobre (Cu) é um contaminante frequente das águas residuais, o que pode levar a intoxicação humana e danos ambientais. A hidroxiapatita (HAP) pode ser utilizada para remoção dessa substância de efluentes, pois é de fácil produção e alto rendimento. Assim, o presente estudo objetivou analisar a influência de vários fatores (factorial design) na adsorção do Cu+2 em solução. A HAP foi produzida por meio de precipitação aquosa e, subsequentemente, caracterização por difração de raios X (DRX), espectroscopia no infravermelho por transformada de Fourier (FTIR), espectroscopia por energia dispersiva (EDS) e microscopia eletrônica de transmissão (TEM). A influência das variáveis pH, concentração inicial (Ci) e massa adsorvente na adsorção de Cu+2 foi analisada por intermédio de um planejamento fatorial 12 (23), com 4 pontos centrais. As três variáveis analisadas foram estatisticamente significantes, sendo possível observar remoções acima de 80% do metal dissolvido em solução. A análise de variância (ANOVA) mostrou que o pH da solução (1), a massa adsorvente (3), a concentração inicial de metal (2) e a interação 2x3 (23) foram estatisticamente significantes. A eficiência máxima de remoção de Cu+2 obtida no procedimento de otimização foi de 85,33%.

ABSTRACT Copper is a frequent contaminant of wastewater, which can lead to human intoxication and environmental damage. The hydroxyapatite (HAP) can be used to remove this substance from wastewater, as it is easy to produce and has high yield. Thus, the present study aimed to analyze the influence of several factors (factorial design) on the adsorption of Cu+2 in solution. HAP was produced by means of aqueous precipitation and subsequently characterized by XRD, FTIR, EDS, and TEM. The influence of the variables pH, initial concentration (Ci), and adsorbent mass on the adsorption of Cu+2 was performed through 12 factorial design (23), with four central points. The three variables analyzed were statistically significant, being possible to observe removals above 80% of the dissolved metal in solution. The analysis of variance (ANOVA) showed that the pH of the solution (1), the adsorbent mass (3), the initial concentration of metal (2), and the interaction 2×3 were statistically significant. The maximum Cu+2 removal efficiency obtained in the optimization procedure was 85.33%.

Antibacterial Activity Analysis of Hydroxyapatite Based Materials with Fluorine and Silver / Análisis de la Actividad Antibacteriana de Materiales a Base de Hidroxiapatita con Flúor y Plata

ABSTRACT This investigation aims to evaluate the antibacterial activity of nanostructured hydroxyapatite based materials doped with silver and fluorine, to be used as a biomaterial with antibacterial activity. Four different formulations were prepared by combustion method: hydroxyapatite, hydroxyapatite-fluorine, hydroxyapatite-silver-fluorine and hydroxyapatite-silver, with 2% of the doping agents. X-ray diffraction technique was used to determine the mineralogy, identifying the presence of Ca5(PO4)3OH, Ca2P2O7, Ag3PO4, AgCa10(PO4)7 Ca5(PO4)3F and CaF2 phases for the studied samples. Scanning electron microscopy was used to study the morphological structure and it showed homogeneous crystallization of the hydroxyapatite and the inclusion of dopant agents. The antibacterial activity was determined using a modified inhibition test zone to observe if the bacteria (E. faecalis) was susceptible to the antimicrobial agent by the appearance of the zone of inhibition on the agar plate. Both the hydroxyapatite-silver and the hydroxyapatite-silver-fluorine materials generated an inhibition zone. It was possible to determine the minimum inhibitory concentration needed to kill most viable organisms after 48 hours of incubation using the broth microdilution method, resulting in 75 µg/ml and 200 µg/ml for the hydroxyapatite-silver and the hydroxyapatite-silver-fluorine formulation, respectively. These materials could be used for the development of new biomaterials that can be used in dental applications.

RESUMEN El objetivo de esta investigación es analizar la actividad antibacteriana de materiales nanoestructurados a base de hidroxiapatita con iones de flúor y plata que le confieran características particulares para que pueda ser utilizado como un biomaterial con actividad antimicrobiana. Se realizaron cuatro formulaciones distintas: hidroxiapatita, hidroxiapatita-flúor, hidroxiapatita-plata-flúor e hidroxiapatita-plata con un 2% de los agentes dopantes. La síntesis del material se realizó a través del método de combustión. La caracterización mineral se realizó a través de difracción de rayos X identificando las siguientes fases en las diversas formulaciones: Ca5(PO4)3OH, Ca2P2O7, Ag3PO4, AgCa10(PO4)7 Ca5(PO4)3F and CaF2. La estructura morfológica se analizó a través de microscopía electrónica de barrido que muestra la formación de estructuras compactas, presencia de cristales y la incrustación de flúor y plata. Se analizó la actividad antimicrobiana utilizando una prueba modificada para la observación del halo de inhibición, encontrándose solamente que los materiales que contenían plata-flúor y plata generaron dicho halo de inhibición. Por otra parte, usando la prueba de microdilución en pozo se encontró que la concentración mínima inhibitoria para el material de HA-Ag fue de 75 μg/ml y para el material de HA-Ag-F fue de 200 μg/ml, después de 48 horas de incubación utilizando E. faecalis.

Biological properties of experimental methacrylate-based sealers containing calcium phosphates

Abstract This study aimed to evaluate, in vitro and in vivo, the biocompatibility of experimental methacrylate-based endodontic sealers containing α-tricalcium phosphate (α-TCP) or nanostructured hydroxyapatite (HAp). Experimental methacrylate-based dual-cure sealers with the addition of α-TCP or HAp, at 10%wt were formulated and compared to AH Plus (AHP). Cell viability was assessed by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT), and sulforhodamine B (SRB). Sealers were implanted in rats' subcutaneous tissue and histologically evaluated. Bioactivity was assessed by alkaline phosphatase enzyme activity (ALP) and Alizarin Red (AR), using apical papillary cells (SCAPs), and by the bone deposition measured in surgical cavities on rats' femur filled with AH Plus or α-TCP. In both viability assays, HAp and AHP sealers were similar, and α-TCP presented lower viability compared to the others at MTT assay (p<0.05). A gradual decrease of the inflammatory response according to the periods was observed and AHP was the only that presented giant cells (7-day period). Collagen fibers condensation increased according to the periods, with no differences among sealers. There was an increase at ALP activity and mineralized nodules deposition according to periods. HAp and α-TCP presented higher values for ALP activity at 5 days and at 5, 10, and 15 days for AR and were different from AHP (p<0.05). α-TCP presented superior values at 10 and 15 days compared to HAp and AHP for AR (p<0.05). At 90 days, α-TCP and control (empty cavity) showed high bone deposition compared to AHP (p<0.05). α-TCP and HAp, in a methacrylate-based sealer, presented biocompatibility and bioactivity, with the potential to be used as endodontic sealers in clinical practice. Further investigations are required to gain information on the physicochemical properties of these sealers formulation before its clinical implementation.

Resumo O objetivo deste estudo foi avaliar a biocompatibilidade de cimentos endodônticos experimentais à base de metacrilato contendo fosfato α-tricálcico ou hidroxiapatita nanoestruturada in vitro e in vivo. Cimentos experimentais de cura dual à base de metacrilato com a adição de fosfato de α-tricálcico (α-TCP) ou hidroxiapatita (HAp), a 10% em peso, foram formulados e comparados com AH Plus (AHP). Viabilidade celular foi avaliada por brometo de 3- (4,5-dimetil-tiazoil) -2,5-difenil-tetrazólio (MTT) e sulforodamina B (SRB). Cimentos foram implantados no tecido subcutâneo dos ratos e avaliados histologicamente. Bioatividade foi avaliada pela atividade da enzima fosfatase alcalina (ALP) e Alizarin Red (AR) utilizando células da papila apical (SCAPs) e pela deposição óssea, medida em cavidades cirúrgicas no fêmur de ratos preenchidos com AH Plus e α-TCP. Nos dois ensaios de viabilidade, HAp e AHP não apresentaram diferenças estatísticas, α-TCP apresentou menores resultados de viabilidade para o ensaio MTT (p <0,05). Resultados histológicos mostraram que houve uma diminuição do conteúdo inflamatório de acordo com os períodos, e o AHP foi o único grupo que apresentou células gigantes (período de 7 dias). A condensação das fibras colágenas aumentou conforme os períodos, sem diferenças entre os grupos. Houve aumento da atividade da ALP e deposição de nódulos mineralizados de acordo com os períodos. HAp e α-TCP apresentaram maiores valores para a atividade de ALP em 5 dias e em 5, 10 e 15 dias para AR, com diferença para o AHP (p <0,05). O α-TCP apresentou valores superiores aos 10 e 15 dias quando comparado ao HAp e AHP para AR (p <0,05). Aos 90 dias, α-TCP e controle (cavidade vazia) apresentaram maior deposição de tecido ósseo quando comparado ao AHP (p <0,05). α-TCP e HAp, presentes nos cimentos à base de metacrilato, apresentaram biocompatibilidade e potencial para serem utilizados como seladores endodônticos na prática clínica. Investigações adicionais são necessárias para obter informações sobre as propriedades físico-químicas dessas formulações de cimentos antes de sua implementação clínica.