ABSTRACT
A lack of control over blood loss can have catastrophic implications, including death. Although several hemostatic medications have been employed to reduce bleeding, a vast majority of them are ineffective, expensive, or pose health risks to the patient. To overcome these constraints, chitosan-polyethylene glycol (CS-PEG) hemostatic gels loaded with ethanolic extract of Jatropha mollissima sap (EES) were prepared and their hemostatic, physicochemical, and cytotoxic properties were evaluated. The gels were produced by mixing CS with PEG (an external plasticizer) and EES. The phytochemical analysis revealed a significant concentration of total polyphenols and tannins content in the extract and catechin was identified as one of the key compounds of EES. Infrared spectroscopy analysis revealed the presence of EES in the gels, as well as the chemical interaction between CS and PEG. The gels were thermally stable between 25 and 37 °C (ambient and human body temperature range), had pseudoplastic deformation behavior (rheological properties preserved after shearing), were simple to inject (compression force 30 N), and were biocompatible. In vivo experiments showed that both CS-PEG-EES gels exhibited greater hemostatic action in preventing tail hemorrhage in Wistar rats, with decreased bleeding time and blood weight compared with unloaded CS-PEG gels (control groups) and Hemostank, a commercial product. However, the gel prepared with acetic acid was more efficient in controlling bleeding. These findings reveal that CS-PEG-EES gels can reduce hemorrhages and are a potent, simple, and safe hemostatic agent.
ABSTRACT
Aim: To verify the hypothesis that self-ligating brackets favor greater aggregation of microorganisms when compared with conventional brackets. Methods: Four types of self-ligating metal brackets were evaluated. Initially, 50 brackets were divided into five groups (n=10): Morelli Conventional, GAC (In-Ovation R, Dentsply Caulk), Aditek (Easy Clip), Ormco (Damon System) and 3M Unitek (Smart Clip). An in vivo evaluation was carried out in which the brackets were bonded to the mandibular teeth of five healthy individuals who had not undergone previous orthodontic treatment. The right hemiarch brackets were used for bacterial plaque collection and those on the left side were examined by scanning electron microscopy (SEM). Before bracket bonding, the bacterial plaque material aggregated to the tooth surfaces was collected, with the areas of choice being the cervical-buccal and mesial and distal interproximal regions. After 21 days had elapsed since bonding, the plaque adhered to the winglet, channel and cervical regions of the bracket bases was collected. The materials collected were diluted and seeded on Petri dishes onto Mitis salivarius medium specific for S. mutans and non-specified BHI culture medium. Colony forming unit (CFU) counts were performed visually after 24, 48 and 72 h of incubation. Results: Greater bacterial accumulation was observed on the winglets of 3M brackets, with statistical statistically significant differences from the other types (p<0.05). As regards the channel regions, most microorganisms accumulated in the Ormco Group (p<0.05), and in the cervical region of Aditek brackets. In all evaluated regions, those with least bacterial accumulation were the conventional brackets. Conclusions: The hypothesis was confirmed, as the self-ligating brackets were shown to have greater bacterial accumulation when compared with the conventional brackets.
Subject(s)
Orthodontic Brackets , Biofilms , Dental Plaque , MicrobiologyABSTRACT
Aim: This study evaluated assess the mechanical properties and forces produced by transpalatal bars made from low-nickel alloy. Methods: Using a template, a single operator made all transpalatal bars from 0.032" and 0.036" wires of two different alloys, thus originating four groups, namely: A8 (0.032" conventional stainless steel), B8 (0.032" low-nickel stainless steel), A9 (0.036" conventional stainless steel), and B9 (0.036" low-nickel stainless steel). The bars were then activated and mounted onto a device developed to serve as a support for mechanical assay in a universal testing machine (Emic DL 10.000). The values of resilience and ductility were obtained using the Origin 8 software. Results: No statistically significant differences (P > 0.05) were observed between Groups A8 and B8 neither between A9 and B9 for 0.5-, 1.0-, and 5-mm deformations. However, statistically significant differences (P < 0.05) were found in all groups for 15-mm deformation. Groups B8 and B9 showed greater ductility and resilience compared to groups A8 and A9, respectively. Conclusions: Low-nickel stainless steel transpalatal bars release the same amount of force for activations less than 10 mm compared to those made from conventional stainless steel. Mechanically, the low-nickel stainless steel bars are more ductile and resilient.
