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

Avaliação de cimento endodôntico resinoso experimental contendo nanopartículas core-shell Ag@SiO2

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Surface and mechanical properties of adhesives with calcium phosphates challenged to different storage media

To evaluate the behavior of experimental dental adhesives with hydroxyapatite (HAp), alpha-tricalcium phosphate (α-TCP) or octacalcium phosphate (OCP) after storing them in three different media: dry storage, distilled water, or lactic acid. Methods: An experimental adhesive resin was formulated with bisphenol A glycol dimethacrylate, 2-hydroxyethyl methacrylate, and photoiniciator/co-initiator system. HAp (GHAp), α-TCP (Gα-TCP), or OCP (GOCP) were added to the adhesive resin at 2 wt.%, and one group remained without calcium phosphates to be used as a control (GCtrl). The adhesives were evaluated for surface roughness, scanning electron microscopy (SEM), and ultimate tensile strength (UTS) after storing in distilled water (pH=5.8), lactic acid (pH=4) or dry medium. Results: The initial surface roughness was not different among groups (p>0.05). GHAp showed increased values after immersion in water (p<0.05) or lactic acid (p<0.05). SEM analysis showed a surface variation of the filled adhesives, mainly for Gα-TCP and GHAp. GHAp showed the highest UTS in dry medium (p<0.05), and its value decreased after lactic acid storage (p<0.05). Conclusions: The findings of this study showed that HAp, OCP, and α-TCP affected the physical behavior of the experimental adhesive resins in different ways. HAp was the calcium phosphate that most adversely affected the surface roughness and the mechanical property of the material, mainly when exposed to an acid mediu

Análise comparativa do desgaste de materiais odontológicos através de Tribômetro Callowear – ensaio “in vitro”

The aim of present study was to evaluate the wear coeficient of different dental materials submited to ballcrattering test. Different restorative materials were compared to bovine enamel. The samples were made with nylon matrix stripes and had 7mm diameter and 2mm thickness. The samples were submitted to the ballcratering test in a Calowear tribometer (CSEM Instruments Advanced Mechanical Surface Testing) and maded six measures in each sample with different revolutions of the ball: 10, 20, 30, 40, 50 and 60 revolutions. After the crattering generation the samples were avaliated to a Zeiss Axiotech Vario Microscope with SVGA Cam and all cratters photographed. After, the photos were evaluated at UTHSCSA ImageTool for Windows 3.0 and the meaning of measured radius were inserted at SigmaPlot, that gave the wear coefficients by linear regression. To bovine enamel the coefficient was 3,83 X 10-14 m²/N, to microhybrid resin was 3,6542 x 10-14 m²/N, 2,06 x 10-12 m²/N to amalgam and 2,18 x 10-12 m²/N to acrylic resin. In conclusion, bovine teeth presented higher wear resistance and lower wear coefficient than composite resin, amalgam and acrylic resin.O objetivo do presente estudo foi avaliar o coeficiente de resistência ao desgaste de diferentes materiais odontológicos submetidos ao ensaio de micro-abrasão através da metodologia de ball-crattering. Para isso foram avaliados diferentes materiais restauradores em comparação com o esmalte bovino. As amostras foram confeccionadas através de matrizes de nylon bipartida, com 7mm de diâmetro e 2mm de espessura em negativo e após, a resistência ao desgaste foi avaliada em um ensaio de micro abrasão (Ball cratering test) realizado em tribômetro modelo Calowear (CSEM Instruments Advanced Mechanical Surface Testing). Em cada corpo de prova foram feitas seis medições com variação no número de voltas realizadas pela esfera: 10, 20, 30, 40, 50 e 60 voltas. Após a realização das crateras o corpo de prova foi levado a um Zeiss Axiotech Vario Microscope com câmera SVGA acoplada onde foram fotografadas todas as crateras geradas e após, foram analisadas em UTHSCSA ImageTool for Windows versão 3.0, os valores de raio médio das marcas foram, então levados ao SigmaPlot versão 8.0 que através da correlação dos dados determinou o coeficiente de desgaste através de uma regressão linear. Para os corpos de esmalte bovino foi encontrado o coeficiente de desgaste de 3,83 X 10-14 m²/N, para resina composta micro híbrida 3,6542 x 10-14 m²/N, para amálgama de prata 2,06 x 10-12 m²/N e para resina acrílica autopolimerizável foi de 2,18 x 10-12 m²/N. Após a execução dos ensaios chega-se a conclusão que o esmalte bovino apresentou maior resistência e menor coeficiente de desgaste, seguido por resina composta, amálgama de prata e resina acrílica autopolimerizável

Evaluation of guanidine antifungal solutions for denture base resin: an in vitro study

Antecedentes: Os objetivos deste estudo foram: (1) formular soluções de cloridrato de polihexametileno guanidina (PHM-GH) em diferentes concentrações; (2) avaliar sua atividade antifúngica contra biofilme maduro de Candida albicans em resinas acrílicas; (3) avaliar efeitos na resistência à flexão e rugosidade da superfície. Métodos: Soluções de PHMGH foram formuladas com água destilada e 0,125, 0,250 ou 0,5% em peso de PHMGH. Um grupo sem PHMGH foi usado como controle. Para análise da atividade antifúngica, amostras de resina acrílica foram contaminadas com C. albicans, e imersas em soluções de PHMGH ou água destilada por 5 ou 10 min. Resistência à flexão final e rugosidade da superfície foram avaliadas. Resultados: Todas as soluções de PHMGH aos 5 ou 10 minutos apresentaram atividade antifúngica em comparação ao grupo controle (pBackground: The purposes of this study were: (1) to formulate polyhexamethylene guanidine hydrochloride (PHMGH) solutions at different concentrations; (2) to evaluate their antifungal activity against a mature biofilm of Candida albicans on acrylic resins; (3) to evaluate possible effects on acrylic resins flexural strength and surface roughness. Methods: PHMGH solutions were formulated with distilled water and 0.125, 0.250, or 0.5 wt.% of PHMGH. One group without PHMGH was used as control. For antifungal activity analysis, acrylic resin specimens were contaminated with C. albicans. Specimens were immersed in PHMGH solutions or distilled water for 5 or 10 min. Ultimate flexural strength and surface roughness of acrylic resins were evaluated. Results: All PHMGH solutions at 5 or 10 min showed antifungal activity compared to the control group (

Brazilian dentistry research productivity : state level socioeconomic, educational and structural factors

Aim: To explore socioeconomic, educational and research factors associated with dental research productivity at the state level in Brazil. Methods: The authors used the Scopus database to identify dental articles published from 2006 to 2016 associated with Brazilian universities at the state level. Several social, economic, educational and research structure variables were obtained from the census and National Research Council to predict the rate of articles per 100 thousand inhabitants among the 27 Brazilian states. Rates were fitted in linear weighted least-squared regression with stepwise technique. Twenty-two variables were grouped in six blocks (social, economic, general education, dental education, research workforce and structure). Results: A total of 21189 articles were published, and the state of São Paulo accounted for 46%, followed by Rio Grande do Sul with 9.4%; four states did not publish any articles. There were an average (± standard deviation) of 2.6 (±1.98) published articles per 100 researchers and 13.4 (±9.6) articles per 100 thousand inhabitants. Research structure and workforce explained 92.4% and 87.2% of state variability, respectively, while the final model explained 94.5%. One extra PhD and one extra undergraduate researcher per 100 thousand inhabitants were associated with 11.3 more and 3.5 fewer articles, respectively, while every 10 points (range 0-100) on the Human Development Index (Education Component) was associated with 3.3 more articles. Conclusion: State scientific output has several associated factors, but research workforce and general education variables seem to be good predictors. Large disparities among state research outputs have been described and must be addressed by research and development policies