Determination of setting time of cement-based hydroxyapatite and galactomannan extracted from Adenanthera pavonina L. seeds by the resonant cavity method

Abstract

The setting time of odontological cement is a clinically important parameter because it suggests the time available to perform the treatment after cement preparation. This time cannot be long 6876/2001 and ADA 57/2000. These techniques perform only a superficial analysis in determining the setting time, so, it is not possible to indicate whether the cement dries completely. The aim of this study was to determine the setting time of the cement-based hydroxyapatite (Hap) and galactomannan (Gal) extracted from Adenanthera pavonina L. seeds, by the method of the resonant cavity. Three composites were prepared: HAG (75 wt% of HAp and 25 wt% of Gal were used for the solid phase, while the liquid phase comprised 0.30 mL of distilled water), HAGJET (75 wt% of Hap, 25% of Gal powder with 0.10 mL of catalyst commercial JET (methyl methacrylate and dimethyl-p- toluidine) and 0.20 ml of distilled water were used), and HAGLS( 60 wt% of HAp+ 40 wt% Galactomannan (Gal) solution + 0.10 mL of phosphoric acid, zinc oxide, aluminum hydroxide and water (LS catalyst commercial). The solid phase in each material was dissolved in the liquid corresponding to each composite formed. The insertion of HAG and HAGJET cement in the cavity caused a disturbance in the electric field due to the presence of free water in the sample. This disturbance decreases as the cement harden due to evaporation of free water. The reverse process occurred with the insertion of HAGLS cement into the cavity, since the presence of water in the material is structural. This characteristic caused perturbation in the cavity to increase with the cement hardening. On the basis of the results, the HAG cement had the highest setting time due to the absence of the chemical activator in its preparation; while HAGJET and HAGLS cement that had activators in their production showed the lowest setting times.