Development and characterization of 3CaO.P2O5-SiO2-MgO glass-ceramics with different crystallization degree

The CaO-P2O5-SiO2-MgO system presents several compounds used as biomaterials such as hydroxyapatite (HA), tricalcium phosphate (TCP) and TCP with magnesium substituting partial calcium (TCMP). The beta-TCMP phase with whitlockite structure has interesting biological features and mechanical properties, meeting the requirements of a bioactive material for bone restoration. In this work, the production of Mg-doped TCP, beta-TCMP, has been investigated by crystallization from a glass composed of 52.75 wt% 3CaO center dot P2O5, 30 wt% SiO2 and 17.25 wt% MgO (i.e., 31.7 mol% CaO, 10.6 mol% P2O5, 26.6 mol% MgO and 31.1 mol% SiO2) using heat treatments between 775. and 1100 degrees C for up to 8 h. The devitrification process of the glass has been accompanied by differential scanning calorimetry (DSC), high-resolution X-ray diffraction (HRXRD), relative density and bending strength measurements. The characterization by HRXRD and DSC revealed the occurrence of whitlockite soon after the bulk glass preparation, a transient non-cataloged silicate between 800 degrees C and 1100 degrees C, and the formation of diopside in samples treated at 1100 degrees C as crystalline phases. The overall crystalline fraction varied from 26% to 70% depending on the heat treatments. Furthermore, contraction of the a-axis lattice parameter and expansion of the c-axis lattice parameter of the whitlockite structure have been observed during the heat treatments, which were attributed to the beta-TCMP formation with the partial substitution of Ca2+ by Mg2+. Relative densities near 99% and 97% for the glass and glass-ceramics respectively indicated a discrete reduction as a function of the devitrification treatment. Bending strengths of 70 MPa and 120 MPa were determined for the glass and glass-ceramic material crystallized at 975 degrees C for 4 h, respectively

O custo direto da fratura de fêmur por quedas em pessoas idosas: análise no setor privado de saúde na cidade de Brasília, 2009

OBJECTIVE: to assess the direct cost of surgical treatment of femoral fracture resulting from falls during the hospitalization and surgery up to two months after injury. METHODS: cross-sectional, descriptive and retrospective study conducted in patients of both sexes, aged 60 years or older, from January 2008 to June 2009. Data were extracted from hospital bills of an agreement accredited to private hospital network in the city of Brasilia. RESULTS: the frequency of femoral fracture for females was 76.2%(n=16) and 23.8%(n=5) for males. The average hospital stay for surgery was 7.1 days and 2.7 days in ICU. There were 16 patients with femoral fractures. The average expenditures for surgery was R$39.160,74 resulting from the all R$ 626,572.06. The direct cost of hospitalization was between R$8.293.55 and R$ 139,837.50, but the hospital medical resources used in the postoperative period accounted for 5.7% of the direct cost of hospitalization. CONCLUSIONS: the cost per femoral fracture surgery is significant to the Brazilian private health system and females are more vulnerable than males. The highest costs were with the prosthesis, material and medicines, and they varied according to the type of surgery, hospital stay and age.OBJETIVO: estimar o custo direto dos recursos médico-hospitalares utilizados no tratamento cirúrgico da fratura de fêmur decorrente de quedas durante a hospitalização e pós-operatório até dois meses após a lesão. MÉTODO: estudo transversal, descritivo e retrospectivo em pacientes de ambos os sexos, com 60 anos ou mais de idade, no período de janeiro de 2008 a junho de 2009. Os dados foram extraídos das contas hospitalares de um convênio credenciado à rede hospitalar privada da cidade de Brasília. RESULTADOS: a frequência de fratura por quedas para o sexo feminino foi 76,2% (n=16), e no masculino, 23,8%(n=5), sendo que 66,7% (n=14) das lesões resultaram em fratura de fêmur proximal. A média de permanência hospitalar das cirurgias foi de 7,1 dias e 2,7 dias em UTI. Houve 16 pacientes com fratura de fêmur e a média do tratamento cirúrgico foi R$39.160,75, totalizando R$ 626.572,06. O custo direto dos recursos médico-hospitalares durante a internação ficou entre R$8.293,55 e R$ 139.837,50; já no pós-operatório, corresponderam a 5,7% do custo total da internação. CONCLUSÃO: o custo cirúrgico da fratura de fêmur é considerável para os convênios do sistema de saúde suplementar e confirmou a vulnerabilidade do sexo feminino para as fraturas de quadril. As maiores despesas foram com a prótese, material e medicamentos, e variaram em função do tipo de cirurgia, período de hospitalização e faixa etária.Universidade Católica de Brasília Programa de Pós-graduação em GerontologiaFundação Oswaldo Cruz Escola Nacional de Saúde PúblicaUniversidade Federal de São Paulo (UNIFESP) Núcleo de Pesquisa em Economia da SaúdeUNIFESP, Núcleo de Pesquisa em Economia da SaúdeSciEL

Extracting hydroxyapatite and its precursors from natural resources

Healing of segmental bone defects remain a difficult problem in orthopedic and trauma surgery. One reason for this difficulty is the limited availability of bone material to fill the defect and promote bone growth. Hydroxyapatite (HA) is a synthetic biomaterial, which is chemically similar to the mineral component of bones and hard tissues in mammals and, therefore, it can be used as a filler to replace damaged bone or as a coating on implants to promote bone in-growth into prosthetic implants when used in orthopedic, dental, and maxillofacial applications. HA is a stoichiometric material with a chemical composition of Ca10(PO4)6(OH)2, while a mineral component of bone is a non-stoichiometric HA with trace amounts of ions such as Na+, Zn2+, Mg2+, K+, Si2+, Ba2+, F-, CO3 2-, etc. This review looks at the progress being made to extract HA and its precursors containing trace amount of beneficial ions from biological resources like animal bones, eggshells, wood, algae, etc. Properties, such as particle size, morphology, stoichiometry, thermal stability, and the presence of trace ions are studied with respect to the starting material and recovery method used. This review also highlights the importance of extracting HA from natural resources and gives future directions to the researcher so that HA extracted from biological resources can be used clinically as a valuable biomaterial