Cost-related variables in the public purchase of dental materials for endodontic application: 10-year analysis

Aim: This study analyzed public procurements for different endodontic materials used in the Brazilian public health system and evaluated the variables related to their cost. Methods: A time-series study was performed by screening materials for endodontic application in the public Brazilian Databank of Healthcare Prices from 2010 to 2019. Data were categorized according to material composition and clinical application. The collated variables were used in a multiple linear regression model to predict the impact of unit price in procurement processes. Results: A total of 5,973 procurement processes (1,524,693 items) were evaluated. Calcium hydroxides were found in 79% of the observations (4,669 processes). Prices drop each year by US$1.87 while MTAs and epoxy resins are increasingly purchased at higher prices (US$50.87; US$67.69, respectively). The microregion, the procurement modality, and the type of institution had no influence on unit prices in the adjusted model (p > 0.05). Conclusions: Calcium hydroxide-based materials were the cheapest and most frequently purchased endodontic materials in the public health care system. Novel formulations are being implemented into clinical practice over time and their cost may be a barrier to the broad application of materials such as MTAs, despite their effectiveness

Impact of economic factors and knowledge translation on public procurement for dental adhesive systems

Abstract: This study aimed to screen the public procurement for dental adhesives in a public health system and evaluate the variables associated with the type and cost of purchased materials. A time series was conducted with secondary data collated from the Brazilian Databank of Healthcare Prices (BDHP). All public procurements for adhesive systems registered from 2010 to 2019 were collated. The frequency of purchase was described, and a multiple linear regression model was used to assess the influence of unit price on predictor variables. Multinomial logistic regression was conducted to describe the influence of selected variables on the probability of purchase for different classes of adhesive systems. A total of 2,752 purchases were analyzed, and the total cost of these materials reached US$ 7,022,659.00 in the 10 analyzed years. The 3-step Etch & Rinse adhesives corresponded to 45.63% of the processes, with increased probability of being purchased over time. The process conducted by public universities in recent years, using the auction modality, presented lower unit prices. The year of purchase, the type of institutions, the institution's location, and the procurement modality influenced the procurement process. The performed analyses contribute to the understanding of the variables associated with the procurements for adhesive systems, providing valuable information for rationalizing public expenditure and for implementing evidence-based practices to guarantee cost-effective and clinically effective procedures for users of the Brazilian public healthcare system.

The influence of the particle's size on the setting reaction of sol-gel derived calcium silicate particles / A influência do tamanho de partícula na reação de presa de cimentos de silicate de cálcio produzidos por sol-gel

Introduction: This study aims to analyze the influence of particles size of sol-gel derived calcium silicate particles in the setting reaction of bioactive endodontic cements. Materials and Methods: Sol-gel derived calcium silicate particles were synthesized and sieved to separate the particles in different sizes: CS400, CS200, and CS100. A commercial MTA (Control) was used as control. The particle size and the specific surface area were assessed by laser diffraction and nitrogen adsorption. The cements were prepared with water as the liquid for the reaction. The setting time was conducted according to ISO 6876, and the setting kinetics was analyzed by Fourier trans-formed infrared spectroscopy (FTIR) at different time points between 120s to 72h. Results: The particle size varied from 9.45µm (CS400 ) to 31.01 (Control). The higher specific surface area valuer reached 15.14g/cm2 in the CS400. The smallest particle sizes, the higher specific surface area, and the lowest setting time were found for CS400 (p < 0.05). Control presented the highest setting time (p < 0.05). The FTIR analyses showed the differences in materials structure over time, with faster hydration and crystallization for CS400. The setting kinetics was slower for Control even when compared to a sol-gel derived group with similar particle size. Conclusion:The route of synthesis and the particle size influences the setting reaction of calcium silicate-based cements. The reduction of particle size for sol-gel derived calcium silicates lead to the acceleration of the setting reaction of the produced bioactive endodontic cement.

Introdução: Este estudo tem como objetivo analisar a influência do tamanho de partículas de silicato de cálcio derivadas de sol-gel na reação de presa de cimentos endodônticos bioativos. Materiais e Métodos: Partículas de silicato de cálcio derivadas de sol-gel foram sintetizadas e peneiradas para separar as partículas em diferentes tamanhos: CS400, CS200 e CS100. Um MTA comercial (Controle) foi usado como controle. O tamanho das partículas e a área superficial específica foram avaliados por difração a laser e adsorção de nitrogênio. Os cimentos foram preparados com água como líquido para a reação. O tempo de presa foi conduzido de acordo com a ISO 6876, e a cinética de presa foi analisada por espectroscopia de infravermelho transformada de Fourier (FTIR) em diferentes pontos de tempo entre 120s a 72h. Resultados: O tamanho de partícula variou entre 9,45µm (CS400) e 31,01 (Controle). A maior área de superfície foi encontrada nas partículas do grupo CS400 (15.14g/cm2). Os menores tamanhos de partícula, a maior área de superfície específica e o menor tempo de presa foram encontrados para CS400 (p < 0,05). O Control apresentou o maior tempo de presa (p < 0,05). As análises de FTIR mostraram as diferenças na estrutura dos materiais ao longo do tempo, com hidratação e cristalização mais rápidas para CS400. A cinética de presa foi mais lenta para Control mesmo quando comparado a um grupo derivado de sol-gel com tamanho de partícula semelhante. Conclusão: A rota de síntese e o tamanho das partículas influenciam a reação de endurecimento dos cimentos à base de silicato de cálcio. A redução do tamanho de partícula para silicatos de cálcio derivados de sol-gel leva à aceleração da reação de pega do cimento endodôntico bioativo produzido.

Development of resin-based bioactive endodontic cements with glycerol salicylate and calcium silicate / Desenvolvimento de cimentos endodônticos bioativos à base de resina com salicilato de glicerol e silicato de cálcio

Introduction: The combination of sol-gel derived calcium silicate particles and glycerol salicylate resins may enhance the pyhisico-chemical properties contribute to the unders-tanding of the interaction between these materials. This study aims to evaluate the physical-chemical properties of resin-based bioactive endodontic cements with glycerol salicylate resins and calcium silicate particles. Materials and methods: Calcium silicate was produced by the sol-gel route, while the resin was produced by mixing 60wt% glycerol salicylate, 30wt% methyl salicylate and 10wt% distilled water. Calcium silicate was added in three different concentrations, 50, 40 and 25% by weight. The cement was tested for setting time, flow, radiopacity and pH. Results: The 50:50 group shows the time of 15min8s while the 75:25 shows the time of 256min13s (p < 0.05). The 50:50 group has a lower flow (15.156mm) compared to 60:40 (23.588 mm) and 75:25 (25.396 mm). All radiopacity values were below 3mmAl. All groups showed a pH increase up to 24 hours and the pH value drop was inversely proportional to the amount of calcium silicate. Discussion: Bioactive calcium silicate particles were used in a composite material with a glycerol salicylate resin. Among the tested cements, the combination of 50wt% calcium silicate particles to 50wt% glycerol salicylate resin showed adequate setting time and promoted an increase in water pH. Conclusion: The 50:50 group showed the setting time and the pH, showing that these materials may be able to promote enhanced biological response. The adjustment of flow and radiopacity should be considered for its clinical application.

Introdução: A combinação entre partículas de silicato de cálcio e glycerol salicilato tem potencial para melhorar as propriedades físico-químicas de cimentos endodônticos bioativos. O objetivo deste estudo foi avaliar as propriedades físico-químicas de cimentos resinosos contendo glicerol salicilato e silicatos de cálcio. Materiais e métodos: O silicato de cálcio foi produzido pelo método sol-gel, en-quanto o líquido foi obtido pela mistura de 60% de salicilato de glicerol, 30% de salicilato de metila e 10% de água destilada em peso. O silicato de cálcio foi adicionado em três diferentes concentrações, sendo elas 50, 40 e 25% em peso. O cimento foi testado em relação ao tempo de presa, escoamento, radiopacidade e pH. Resultados: O grupo 50:50 apresentou tempo de presa de 15min8s enquanto o 75:25 apresentou um tempo de 256min13s (p < 0,05). O grupo 50:50 apresentou menor escoamento (15,156mm) em comparação ao 60:40 (23,588mm) e 75:25 (25,396mm). Quanto à radiopacidade, todos obtiveram valores menores que 3mmAl. Todos apresentaram aumento de pH até 24h, e após esse período tiveram quedas inversamente proporcionais a quantidade de silicato de cálcio em cada um. Discussão: Partículas bioativas de silicato de cálcio foram utilizadas em um compósito com base resi-nosa de glicerol salicilato. Dentre os cimentos utilizados, a combinação de 50:50 entre os componentes tem resultados promissores para a aplicação destes materiais. Conclusão: O grupo 50:50 apresentou adequado tempo de presa e pH, indicando que o material pode manter suas propriedades biológicas. A radiopacidade e o escoamento, no entando, devem ser adequadas para aplicação do material.