Dissolution of root canal sealers in EDTA and NaOCl solutions

The Efficacy of Two Novel Retreatment Systems in the Removal of Root Canal Obturating Materials (An In vitro Study)

BACKGROUND: The complete removal of root filling material is one of the main goals of non-surgical endodontic retreatment. Thus, the development of new techniques and instruments aiming to promote this task presents clinical significance. AIM: The purpose of the study was to assess the amount of residual root canal filling materials (gutta-percha/sealer) after using two different endodontic retreatment systems and ultrasonic tip. METHODS: Forty-five mandibular premolar teeth were mechanically instrumented and obturated. Retreatment was performed using two different Endostar RE (Group 2), Rogin retreatment system (Group 3), and ultrasonic tip (Group 1). Roots were separated buccolingually into two halves. A digital camera connected to the stereomicroscope captured images to each half. Image-J software was used to evaluate and measure the areas with remaining filling material in each third (cervical, middle, and apical). RESULTS: Data analysis revealed significant differences between the groups in the coronal, middle, and apical thirds (p < 0.05). The ultrasonic retreatment tips (G1) were significantly more efficient in removing the gutta-percha and sealers compared to the Rogin (G3) and Endostar (G2) retreatment endodontic kits. CONCLUSIONS: All the file systems left some filling material in the canals. Ultrasonic retreatment tip had maximum efficacy for the removal of filling materials in comparison with the retreatment file systems under investigation.

Effects of different irrigation protocols on dentin surfaces as revealed through quantitative 3D surface texture analysis

The combination of ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) has been advocated as an effective irrigation methodology to remove organic and inorganic matter in root canal therapy. Yet, it was suggested that both solutions might lead to structural changes of the dentinal wall surface, depending on the order of application which might affect sealer mechanical retention. This study aims to evaluate the effect of different irrigating protocols on dentin surface roughness using quantitative 3D surface texture analysis. Data stems from 150 human root dentin sections, divided into five groups, each prepared according to one of the following protocols: Negative control; 17% EDTA; 17% EDTA followed by 5.25% NaOCl; 5.25% NaOCl; and 5.25% NaOCl followed by 17% EDTA. Each dentin sample was examined for its three-dimensional surface texture using a high-resolution confocal disc-scanning measuring system. EDTA 17% and the combined EDTA 17% with NaOCl 5.25% showed considerably higher roughness properties compared to the control and to NaOCl 5.25% alone. However, the irrigation sequence did not affect the dentin roughness properties. Therefore, mechanical retention is probably not dependent upon the selection of irrigation protocol sequence.

Properties and applications of calcium hydroxide in endodontics and dental traumatology

Calcium hydroxide has been included within several materials and antimicrobial formulations that are used in a number of treatment modalities in endodontics. These include, inter-appointment intracanal medicaments, pulp-capping agents and root canal sealers. Calcium hydroxide formulations are also used during treatment of root perforations, root fractures and root resorption and have a role in dental traumatology, for example, following tooth avulsion and luxation injuries. The purpose of this paper is to review the properties and clinical applications of calcium hydroxide in endodontics and dental traumatology including its antibacterial activity, antifungal activity, effect on bacterial biofilms, the synergism between calcium hydroxide and other agents, its effects on the properties of dentine, the diffusion of hydroxyl ions through dentine and its toxicity. Pure calcium hydroxide paste has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. Its main actions are achieved through the ionic dissociation of Ca(2+) and OH(-) ions and their effect on vital tissues, the induction of hard-tissue deposition and the antibacterial properties. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. It has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also an effective anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

Influence of sodium hypochlorite and edta on the microtensile bond strength of a self-etching adhesive system

Chemical substances used during biomechanical preparation of root canals can alter the composition of dentin surface and affect the interaction with restorative materials.