Effect of sodium hypochlorite and ethylenediaminotetraacetic acid activated by laser and ultrasonic energy on surface morphology and chemical composition of intracanal dentin.

The aim of the study was to evaluate the structural and chemical changes in intracanal dentin after root canal irrigation with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) using additional activation with a novel Er:YAG Shock Wave-Enhanced Emission Photoacoustic Streaming (SWEEPS), ultrasonic irrigation (UI), and Nd:YAG irradiation. Root canals of extracted human premolars were instrumented with distilled water and distributed into groups according to the irrigation protocol used: Group 1: conventional needle irrigation (CI) with 3% NaOCl; group 2: CI with 15% EDTA; and group 3: CI with NaOCl+EDTA. In group 4, root canals were irrigated with NaOCl+EDTA+NaOCl using the following techniques: CI (group 4A), SWEEPS (group 4B), UI (group 4C). In group 4D, root canals were finally irradiated with Nd:YAG laser. After the irrigation, the intracanal dentin sample was collected and analyzed using spectroscope with a Fourier transformation of infrared spectrum in Attenuated total reflection technique (FTIR-ATR) to calculate apatite/collagen ratio. Scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS) were used to determine its chemical composition. FTIR-ATR showed no significant difference in the phosphate/amid I ratio between the control and the experimental groups (p > 0.05). SWEEPS and UI of NaOCl+EDTA+NaOCl caused the most pronounced decrease of Ca and P (p < 0.05) value compared to CI and control group, and canal wall erosion. SWEEPS and UI of NaOCl+EDTA+NaOCl caused the most pronounced decrease of Ca and P value and significant canal wall erosion. However, no difference in phosphate/amide ratio was reported among groups. RESEARCH HIGHLIGHTS: SWEEPS and UI of NaOCl+EDTA+NaOCl caused the most pronounced decrease of Ca and P values and significant canal wall erosion. There was no difference in phosphate/amide ratio among the irrigation protocols.

Efficiency Evaluation of Various Solvents in Retreatment of Endodontic Filling in Extracted Teeth.

Objectives: The aim of this study was to evaluate the retreatment duration and efficacy of eucalyptol and tea tree oil in engine driven and manual retreatment of epoxy resin based endodontic filling in extracted human teeth. Methods and materials: Sixty human single rooted teeth were randomly divided into two groups. The first group was prepared using hand files, and the second one using Reciproc system. Root canals were filled with gutta-percha points and AH Plus sealer. Retreatment was performed using K-reamers and Hedström files for the first group, and Reciproc instruments for the second group. Each group was divided into two subgroups (n=15) according to the retreatment solvent used (eucalyptol or tea tree oil). Root canals were longitudinaly split and analized with stereomicroscope (15x magnification). The surface of the remaining filling material was measured using an image processing software. Results: There were no statistically significant differences in the area of residual filling material among used solvents, nor in applied technique. Retreatment with Reciproc instruments was significantly faster compared to retreatment using hand files. The manual retreatment technique was faster when tea tree essential oil was used as a solvent compared to eucalyptol. Conclusions: Australian tea tree oil and eucalyptus oil were equally effective in removing endodontic filling material, but none of canals were completely free of the residual filling material. Retreatment with Reciproc instruments was faster compared to retreatment using hand files. The manual retreatment technique is faster when tea tree essential oil is used as a solvent compared to eucalyptol.

Efficacy of Reciprocating Instruments in Retreatment of Bioactive and Resin-Based Root Canal Sealers.

Objective: To compare the effectiveness of reciprocating instruments in removing gutta-percha and bioactive-based (BioRoot RCS and MTA Fillapex) and epoxy resin-based (AH Plus) sealers from root canals based on filling residues and the time required for root canal revision. Material and methods: Root canals of 90 teeth were instrumented with Reciproc R40. All root canals were obturated using the single-cone technique with Reciproc R40 gutta-percha and with one of the selected sealers. Samples with oval, straight canals were used and randomly divided into three groups: (i) filled with AH Plus sealer and gutta-percha (n=30); (ii) filled with MTA Fillapex and gutta-percha (n=30); (iii) filled with BioRoot RCS and gutta-percha (n=30). Each group was divided into two subgroups (n=15) according to the retreatment instrument used (Reciproc M-Wire R25/R40 or Reciproc blue RB25/RB40). Root canals were longitudinally split and analyzed with a stereomicroscope at 15 × magnifications in the coronal, middle, and apical third. Computational analyses were performed with the Image J software. Data were compared using the Kruskal-Wallis test and Mann-Whitney U test. Results: While no statistically significant differences in the residual material surface were found for Reciproc Blue, Reciproc M-Wire showed significantly higher residual material surface for AH Plus and MTA Fillapex compared to BioRoot RCS. For AH plus. Residual material surface was significantly lower for Reciproc Blue than for Reciproc M-Wire. In contrast, BioRoot RCS showed a significantly higher residual material surface for Reciproc Blue. Conclusions: Calcium silicate-containing sealers were more retrievable compared to AH Plus, with fewer sealer remnants and shorter retreatment time. Retreatment with Reciproc M-Wire instruments was superior to Reciproc blue instruments in retreatment of BioRoot RCS. However, none of the sealers were removed completely.