Intracanal medication is considered an alternative after instrumentation in the case of pulp necrosis. However, the elimination of this medication plays an important role in the obturation process, which is why various chelating solutions have currently been studied for this purpose. Therefore, this study aimed to analyze the irrigant based on alendronic acid (AA), which contains in its chemical structure functional groups capable of forming complexes with Ca2+ ions. 90 single-rooted teeth were crowned and standardized to a length of 13 mm. They were instrumented with a progressive K file (Dentsply Maillefer) from #15 to #30. Ca(OH)2 was placed as intracanal medication for 7 days. The roots were randomly divided into the following 4 experimental groups (n=13) according to the irrigant used: 2.25% NaClO, calcium suspension, 0.22% AA, and 10% citric acid; as well as negative (n=5; saline solution) and positive controls (n=5, 17% EDTA). The roots were divided longitudinally and the % of permeable dentinal tubules (% PDT) was determined by thirds (cervical, middle and apical), by analyzing the micrographs obtained by scanning electron microscope (SEM) and the imageJ program. The quantification of the remaining Ca2+ was determined using the Arsenazo III technique. The Kruskal Wallis test was used for the % of permeable dentinal tubules where a significant difference was determined for the different thirds (p<0.005). In the apical third, citric acid and AA irrigants presented a median of 17.71 and 17.51 % PDT respectively. In relation to the quantification of the remaining total calcium, the lowest value was found with AA with a concentration of 4.83 mmol/L. The 0.22% AA solution has the same capacity to remove Ca(OH)2 from the root canal walls as 17% EDTA and 10% citric acid. Key words:Alendronic acid, calcium hydroxide, citric acid, EDTA, irrigant solution,root canal.

Objective: The present study aimed to evaluate the changes in the physicochemical properties of dentine after irrigation with a solution of 0.22% alendronic acid (AA) as a chelating agent compared to 17% ethylene-diaminetetraacetic acid (EDTA).Methods: A total of 48 extracted premolars and molars that were intact, free of caries or cracks, without root canal treatment and restorations were collected. The roots were randomised into three groups (n=16): Group A: Distilled Water (dH2O); Group B: 17% EDTA, and Group C: 0.22% AA. Longitudinal sections of the dentine with a root of 1x1x10 mm were made with a diamond disc and a low-speed handpiece for bending tests (n=9). For morphological analysis, images were taken with a scanning electron microscope, crystallographic analysis with X-ray diffraction, and chemical analysis with Fourier Transform Infrared Spectroscopy (FTIR) and Vickers Hardness. For this purpose, cross-sections were made through the root using the Isomet to obtain 3 mm thick dentine discs (n=14). The samples were stored in dH2O for up to 24 h before use and dried at room temperature before exposure to chelating solutions for 1 h in a Stuart STR6D mixer at 50 rpm. For data comparison, the Kruskal-Wallis statistical test was used (α=0.05).Results: The chelating solutions of EDTA and AA cause alterations in the physicochemical structure of dentine, attacking mainly the inorganic part (Hydroxyapatite), which was observed in the decrease in intensity of the peaks in the X-ray diffraction pattern of hydroxyapatite. This generated a greater exposure of the collagen fibres that were observed in SEM and the increase in the bands characteristic to Collagen Type I in the infrared spectrum at 1645, 1550, and 1240 cm–1 belonging to amide I (C=O), amide II (N-H) and amide III (C-N), significantly affecting its dentine hardness (p=0.001).Conclusion: AA can be used as a chelating agent in the area of dentistry. It does not generate a significant demineralising effect that modifies the physicochemical properties of dentine, as observed with EDTA.

Gutta-percha (Gp) is an inert thermoplastic polymer used as a filling to replace the dental pulp space, which has been reformulated to improve its three-dimensional sealing properties. Therefore, this study aimed to analyze the physical, chemical and thermal properties of two types of gutta-percha filling. As well as measuring the temperature distribution along the cone at the time of cutting through an in-situ test. Two commercially available brands of gutta-percha point were investigated: Conform Fit TM Gutta-Percha for ProTaper Gold® (PTG) (Dentsply Sirona), and Hygenic Gutta-Percha (Coltene whaledent). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were selected for the thermal characterization of materials, and Fourier Transform Infrared Spectroscopy (FT-IR) for the chemical analysis of Gp cones. Regarding temperature distribution, it was evaluated using a thermographic camera (FLIR ONE® PRO by MicroUSB P/N 435-0011-01) at 0 to 20 s after the cutting process (n=11/group). Both materials have three fusion endotherms associated with the three crystalline phases of Gp, with similar temperatures but enthalpies that differ by 60%, the fusion enthalpy being higher for Conform Fit. In the chemical characterization, elements such as Zn, C, O, Ba, S and Si were found in both materials but in different proportions. Regarding the content of fillers, the Conform Fit presented around 30% of Gp polymer and 25% for the Hygenic. The morphological characterization shows a microtexturized coating in the form of bars on a micrometric scale for the Conform Fit, which could favor a better three-dimensional seal. In addition to that, in heat transfer studies they showed greater temperature control. The characterization of the materials allowed us to see the variation in terms of their composition and configuration to the Gp cones of two commercial brands. These variations directly modify the thermal behavior of the material. Key words:Gutta-percha, Conform Fit, Infrared thermography, Differential Scanning Calorimetry, Infrared Spectroscopy.

This study aimed to synthesize and characterize cassava starch-based (S) scaffolds functionalized with decellularized extracellular matrix (dECM) and isosorbide dinitrate (ISDN) for wound healing. The scaffolds were synthesized via the casting method and evaluated for physicochemical, mechanical, and morphological properties, as well as ISDN release and hemocompatibility. Swelling and degradation tests revealed a biphasic behavior, with high water absorption followed by controlled degradation. The ISDN release followed a biphasic pattern, fitting the Korsmeyer–Peppas model. Hemolysis tests confirmed biocompatibility, with hemolysis levels below 2%. Among the formulations, the scaffold containing 12.5% ECM and 40 mg ISDN exhibited optimal mechanical stability, controlled drug release, and biocompatibility. These findings suggest that starch/ECM/ISDN scaffolds hold potential for wound healing applications. Further studies should focus on in vivo evaluation and cytotoxicity assessments to confirm their clinical applicability.