Experimental Mineral Trioxide Aggregate Research Articles

Addition of phosphates and chlorhexidine to resin‐modified MTA materials

To evaluate the properties of experimental mineral trioxide aggregate (MTA) resin-modified materials for root-end filling procedures, varying their compositions regarding the addition of hydroxiapatite (HA) or dicalcium phosphate dihydrate, with or without chlorhexidine digluconate. White MTA (Angelus, Londrina, Brazil) was used as a reference material. Degree of conversion (DC) was evaluated by Fourier transformed infrared (FTIr) spectroscopy (n = 5). Flowability (n = 3) and radiopacity (n = 3) were evaluated following ISO 6876:2001 methods. For splitting tensile strength analysis, cylindrical samples (n = 10) were subjected to compressive load using a universal testing machine (Instron Corporation, Norwood, MA). Water sorption and solubility tests were performed according to ISO 4049:2009 methods. Calcium ion release and pH analysis (n = 10) were evaluated using a pH meter (Orion, Watsonville, CA). Cytotoxicity (n = 8) of materials extracts was evaluated as cell viability percentage. Statistical analysis was performed using Kolmogorov-Smirnov for normal distribution and data was subjected to one-way ANOVA and Tukey test (α = 0.05). Addition of chlorhexidine digluconate reduced DC mean values for experimental materials (<50%). White MTA demonstrated lower flowability (5.3 mm) and higher radiopacity (9.8 mm Al), splitting tensile strength (9.1 MPa), solubility (8.2 μg/mm3 ), calcium ion release (~26.5 ppm), cytotoxicity (55.2%), and pH mean values (10.8), when compared to experimental materials. All groups demonstrated a decrease in calcium release (<85%) and pH (<13%). Formulation containing HA demonstrated similar pH values after 28 days when compared to white MTA. Evaluated experimental resin-modified MTA based materials without chlorhexidine digluconate showed satisfactory results for all physico-chemical properties tested and cytotoxicity. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2195-2201, 2019.

Biocompatibility of an experimental MTA sealer implanted in the rat subcutaneous: Quantitative and immunohistochemical evaluation

The tissue reaction promoted by an experimental mineral trioxide aggregate sealer (MTAS) in the rat subcutaneous was evaluated by morphological and morphometric analyses. In the animals from each group (n = 20), polyethylene tubes filled with MTAS, Portland cement (PC) or MTA were implanted in the dorsal subcutaneous. In the control group, empty tubes were implanted. After 7, 14, 30, and 60 days, the specimens were fixed and embedded in paraffin. In the HE-stained sections, the numerical density of inflammatory cells (IC) in the capsule was evaluated and statistical analyses performed (p ≤ 0.05). The expression of osteopontin (OPN) was evaluated by immunohistochemistry. The von Kossa method for detection of calcified structures was also performed. A moderate inflammatory process in the capsule was seen in all groups, at 7 and 14 days. At 60 days, significant reduction in the number of IC was verified in comparison to initial periods; however, significant differences were not verified among the groups. OPN immunolabeling was observed in the fibroblasts cytoplasm of the capsule next to the implants. Structures von Kossa-positive were observed in the capsule adjacent to all materials implanted at 7, 14, and 30 days. The results strongly indicate that MTAS presents biocompatibility similarly to MTA and PC.

Inflammatory and bone regulators expression in murine macrophages under exposure of commercial and experimental mineral trioxide aggregate

Mineral trioxide aggregate (MTA) has been used in a variety of surgical and non-surgical endodontic applications. The aim of this study was to evaluate the gene expression and protein production of TNF-α, IL-1β and IL-6, as well as the gene expression of RANKL and OPG using both commercial and experimental MTA in macrophage cell cultures. Peritoneal macrophage cell culture was performed. Viability, gene expression of cytokines, RANKL and OPG, and protein levels in experimental- and commercial-grey MTA co-cultured with peritoneal macrophages was determined by tryptan blue, real time PCR and ELISA. The expression of TNF-α for both commercial and experimental MTA was higher, while the expression of IL-1β and IL-6 was similar when compared to the negative control. At protein expression level, no differences were observed between the negative control and cements. RANKL did not show a significant improvement in gene expression when compared with the negative control, but OPG expression in cement samples was higher when compared to the negative control. This study suggests that commercial and experimental MTA promotes anti-inflammatory processes, as well as bone healing capacity.

PH, Calcium Ion Release, and Setting Time of an Experimental Mineral Trioxide Aggregate–based Root Canal Sealer

Introduction An experimental mineral trioxide aggregate sealer (MTAS) has been developed for use as a root canal sealer. The aim of this study was to evaluate the setting time, pH, and calcium ion release of MTAS compared with white Portland cement (CPB-40; Votorantin Cimentos, Camargo Correa SA, Pedro Leopoldo, MG, Brazil), white MTA Angelus (MTA; Angelus, Londrina, PR, Brazil), and AH Plus (Dentsply DeTrey, Konstanz, Germany). Methods For the evaluation of setting time, each material was analyzed using Gilmore-type needles. Polyethylene tubes with the materials were immersed in distilled water for the measurement of pH (digital pH meter) and calcium release (atomic absorption spectrophotometry). The evaluations were performed at 3, 6, 12, 24, and 48 hours and 7, 14, and 28 days. Data were analyzed by analysis of variance and the Tukey test at 5% significance level. Results MTAS showed higher calcium release at all experimental periods, a greater increase in pH up to 48 hours and the longest setting time. Conclusions MTAS presented favorable properties for its indication as a root canal sealer.