Ph e liberação de cálcio de materiais forradores / Ph and calcium Ion release of pulp-capping materials

Objetivo: Avaliar o pH e liberação de íons cálcio dos materiais forradores a base de hidróxido de cálcio não fotopolimerizável (Hydro C), um fotopolimerizável (Biocal) e MTA. Os materiais foram manipulados e inseridos em tubos de 1 cm de comprimento e 1 mm de diâmetro. Os tubos foram preenchidos e imediatamente imersos em frascos contendo 10 mL de água deionizada. Os tubos foram removidos dos frascos depois de 10 minutos, 24, 48 horas, 7, 15 e 30 dias, e a liberação de íons cálcio e hidroxila foi mensurada com um pHmetro e espectrofotômetro de absorção atômica, respectivamente. Os dados foram comparados pela análise de variância a dois critérios, e as comparações individuais pelo teste de Tukey-Kramer, com nível de significância de 5%. Com relação a liberação de íons calcio, no periodo de 10 minutos ocorreram diferenças significantes (P<0,05) nas comparações do MTA com os outros dois materiais. Nos períodos de 24 e 48 horas os três materiais se diferenciaram estatisticamente (P<0,05) entre si. Na análise de 7 e 15 dias ocorreram diferenças significantes (P<0,05) nas comparações entre: MTA e Biocal, e no confronto entre Hydro C e Biocal. Na avaliação de 30 dias as diferenças significantes (P<0,05) ocorreram nas comparações do MTA com os demais materiais. Com relação ao pH, no período de 10 minutos e 24 horas não ocorreram diferenças significantes (P>0,05). Nos períodos de 48 horas ocorreu diferença estatística (P<0,05) nas comparações do BioCal com os outros dois materiais. Na análise de 7 dias ocorreu diferença significante (P<0,05) na comparação entre MTA e Biocal. Na avaliação de 15 dias ocorreram diferenças significantes (P<0,05) na comparação do Hidro C com os demais materiais. Na análise de 30 dias ocorreram diferenças significantes (P>0,05) nas comparações. Conclui-se que todos os materiais foram capazes de liberar íons cálcio e hidroxila.

Objective: Evaluate the pH and calcium ion release from the pulp-capping materials based on calcium hydroxide does not light-cured (Hydro), a light-cured (Biocal) and MTA. The materials were manipulated and inserted into tubes of 1 cm in length and 1 mm in diameter. The tubes were completed and immediately immersed in vials containing 10 mL of deionized water. The tubes were removed from bottles after 10 minutes, 24, 48 hours, 7, 15 and 30 days, and calcium and hydroxyl ions release was measured with an atomic absorption spectrophotometer and pHmetro, respectively. The data were compared by analysis of variance on two criteria, and individual comparisons by Tukey-Kramer test with significance of 5%. Regarding the calcium ion release, in period of 10 minutes there were significant differences (P<0 .05) MTA comparisons with the other two materials. During periods of 24 and 48 hours the three materials have differentiated statistically (P<0 .05) among themselves. Analysis of 7 and 15 days there were significant differences (P<0 .05) in the comparisons between: MTA and the confrontation between Biocal and Hydro C and Biocal. 30 days evaluation of significant differences (P<0 .05) occurred in MTA comparisons with other materials. With regards to pH, within 10 minutes and 12:0 am not significant differences occurred (P>0 .05). During periods of 48 hours there was statistical difference (P0 .05) in BioCal's comparisons with the other two materials. In During periods of 48 hours there was statistical difference (P<0 .05) in BioCal's comparisons with the other two materials. Analysis of 7 days there was significant difference (P<0 .05) in the comparison between MTA and Biocal. In 15 days trial significant differences occurred (P<0 .05) in comparison with the other's Hydro C materials. In the analysis of significant differences occurred 30 days (P<0 .05) in the comparisons. It is concluded that all materials were able to release calcium ions and hydroxyl.

Effect of ultrasonic activation on pH and calcium released by calcium hydroxide pastes in simulated external root resorption.

INTRODUCTION: The purpose of this study was to analyze the influence of ultrasonic activation of calcium hydroxide (CH) pastes on pH and calcium release in simulated external root resorptions. METHODS: Forty-six bovine incisors had their canals cleaned and instrumented, and defects were created in the external middle third of the roots, which were then used for the study. The teeth were externally made impermeable, except for the defected area, and divided into the following 4 groups containing 10 samples each according to the CH paste and the use or not of the ultrasonic activation: group 1: propylene glycol without ultrasonic activation, group 2: distilled water without ultrasonic activation, group 3: propylene glycol with ultrasonic activation, and group 4: distilled water with ultrasonic activation. After filling the canals with the paste, the teeth were restored and individually immersed into flasks with ultrapure water. The samples were placed into other flasks after 7, 15, and 30 days so that the water pH level could be measured by means of a pH meter. Calcium release was measured by means of an atomic absorption spectrophotometer. Six teeth were used as controls. The results were statistically compared using the Kruskal-Wallis and Mann-Whitney U tests (P < .05). RESULTS: For all periods analyzed, the pH level was found to be higher when the CH paste was activated with ultrasound. Calcium release was significantly greater (P < .05) using ultrasonic activation after 7 and 30 days. CONCLUSIONS: The ultrasonic activation of CH pastes favored a higher pH level and calcium release in simulated external root resorptions.

Evaluation of the physical and chemical properties of two commercial and three experimental root-end filling materials.

OBJECTIVE: The aim of this study was to evaluate the pH, calcium release, setting time, and solubility of two commercially available mineral trioxide aggregate (MTA) cements (white MTA Angelus and MTA Bio), and of three experimental cements (light-cured MTA, Portland cement with 20% bismuth oxide and 5% calcium sulfate, and an epoxy resin-based cement). STUDY DESIGN: For evaluation of pH and calcium ion release, polyethylene tubes with 1.0 mm internal diameter and 10.0 mm length were filled with the cements and immediately immersed in flasks containing 10 mL deionized water. After 3, 24, 72, and 168 hours, the tubes were removed and the water from the previous container was measured for its pH and calcium content with a pH meter and an atomic absorption spectrophotometer. For analysis of the setting time, Gilmore needles weighing 100 g and 456.5 g were used, in accordance with the American Society for Testing and Materials specification no. C266-03. Solubility of each cement was also tested. RESULTS: All the cements were alkaline and released calcium ions, with a declining trend over time. After 3 hours, Portland cement + bismuth oxide and MTA Bio had the highest pH and light-cured MTA the lowest. After 1 week, MTA Bio had the highest pH and light-cured MTA and epoxy resin-based cement the lowest. Regarding calcium ion release, after 3 hours, Portland cement + bismuth oxide showed the highest release. After 1 week, MTA Bio had the highest. Epoxy resin-based cement and light-cured MTA had the lowest calcium release in all evaluation periods. Regarding setting times, white MTA Angelus and MTA Bio had the shortest, Portland cement + bismuth oxide had an intermediate setting time, and the epoxy resin-based cement had the longest. The materials that showed the lowest solubility values were the epoxy resin-based cement, Portland cement + bismuth oxide, and light-cured MTA. The highest solubility values were presented in white MTA Angelus and MTA Bio. CONCLUSIONS: The white MTA Angelus and MTA Bio had the shortest setting times, higher pH and calcium ion release, and the highest solubility. In contrast, the epoxy resin-based cement and light-cured MTA showed lower values of solubility, pH, and calcium ion release.

Evaluation of pH and calcium ion release of calcium hydroxide pastes containing different substances.

INTRODUCTION: The objective of this study was to evaluate the pH and calcium ion release of calcium hydroxide pastes associated with different substances. METHODS: Forty acrylic teeth with simulated root canals were divided into 4 groups according to the substance associated to the calcium hydroxide paste: chlorhexidine (CHX) in 2 formulations (1% solution and 2% gel), Casearia sylvestris Sw extract, and propylene glycol (control). The teeth with pastes and sealed coronal accesses were immersed in 10 mL deionized water. After 10 minutes, 24 hours, 48 hours, and 7, 15, and 30 days, the teeth were removed to another container, and the liquid was analyzed. Calcium ion release was measured by atomic absorption spectrophotometry, and pH readings were made with a pH meter. Data were analyzed statistically by analysis of variance and Tukey test (alpha = 0.05). RESULTS: Calcium analysis revealed significant differences (P < .05) for 1% CHX solution and 2% CHX gel at 10 minutes. After 24 hours, 2% CHX gel x Control and 2% CHX gel x 1% CHX solution differed significantly (P < .05). After 48 hours, there were significant differences (P < .05) for 2% CHX gel x Control and Extract x Control. No differences (P > .05) were observed among groups in the other periods. Regarding the pH, there were significant differences (P < .05) for 2% CHX gel x Control and 2% CHX gel x 1% CHX solution after 48 hours and for 2% CHX gel x Control after 15 days. In the other periods, no differences (P > .05) were observed among groups. CONCLUSIONS: All pastes behaved similarly in terms of pH and calcium ion release in the studied periods.