Antimicrobial activity of root canal irrigants associated with cetrimide against biofilm and planktonic Enterococcus Faecalis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of the physicochemical properties and push-out bond strength of mta-based root canal cement

Aim: This study investigated the flowability, setting time, pH, calcium release and bond strength of a MTA-based cement (MTA Fillapex®) compared to AH Plus and Sealapex. Materials and methods: For the flowability test, the ISO 6876:2001 specification was utilized and for the setting time test, the ASTM C266-03 specification was utilized. For the pH and calcium release measurements, 10 samples were prepared for each group and analyzed for several different periods. For the push-out test, dentin disks were distributed into three groups, according to the cement utilized and into three subgroups, according to the root third (n = 10). After obturation, the specimens underwent push-out testing. The data were compared statistically using a significance level of 5%. Results: The flowability of all materials was found to be similar (p > 0.05). The setting times were different among the groups tested (MTA Fillapex < Sealapex < AH Plus) (p < 0.05). At days 7 and 28, the MTA Fillapex presented the higher pH values (p < 0.05). At 24 hours and at 14 days, the calcium release of the MTA Fillapex was similar to that of Sealapex (p > 0.05). AH Plus presented the lowest pH and calcium release values (p < 0.05). In all root thirds, the adhesion to the dentin of the MTA Fillapex and Sealapex were significantly lower than that of AH Plus (p < 0.05). Conclusion: MTA Fillapex and Sealapex presented several similar properties and both were found to be different than AH Plus. Clinical significance: This study evaluated the physicochemical and mechanical properties of new MTA-based root canal cement, in order to use this scaler in root canal fillings. MTA Fillapex showed satisfactory properties for clinical use.

Adaptation and penetration of resin-based root canal sealers in root canals irradiated with high-intensity lasers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of root canal status on periodontal healing after surgical injury in dogs.

This study was carried out to observe if the status of the root canal might influence the healing process of surgically prepared experimental periodontal lesions. Forty tooth roots from four dogs were divided into four different groups: a) root canals with vital pulps, b) root canals open to the oral environment, c) root canals infected and filled with zinc oxide eugenol cement, and d) root canals infected and filled with calcium hydroxide. By means of a surgical intervention, a cavity was prepared in the medium portion of the roots. Six months later, the specimens were removed and prepared for histological analysis. The results, which were submitted to statistical analysis, showed that the status of the root canals influenced the healing process of the experimental periodontal lesions. In the groups where the root canals were filled, calcium hydroxide gave the best results. In the group with root canals left open to the oral environment, resorption of the dentin of the experimental cavities, was the most obvious observation. However, it did not prevent the repair process, only slowed it down.

Push-out bond strength and SEM evaluation of a new bonding approach into the root canal

Objective: This study evaluated the performance of different adhesive systems in fiber post placement aiming to clarify the influence of different hydrophobic experimental blend adhesives, and of one commercially available adhesive on the frictional retention during a luting procedure. Material and Methods: One luting agent (70 Wt% BisGMA, 28.5% TEGDMA; 1.5% p-tolyldiethanolamine) to cement fiber posts into root canals was applied with 4 different adhesive combinations: Group 1: The etched roots were rinsed with water for 30 s to remove the phosphoric acid, then rinsed with 99.6% ethanol for 30 s, and blot-dried. A trial adhesive (base to catalyst on a 1: 1 ratio) was used with an experimental luting agent (35% Bis-GMA, 14.37% TEGDMA, 0.5% EDMAB, 0.13% CQ); Group 2: A trial adhesive (base to catalyst on a 1: 2 ratio) was luted as in Group 1; Group 3: One-Step Plus (OSP, Bisco Inc.) following the ethanol bonding technique in combination with the luting agent as in Group 1; Group 4: OSP strictly following the manufacturer's instructions using the luting agent as in Group 1. The groups were challenged with push-out tests. Posted root slices were loaded until post segment extrusion in the apical-coronal direction. Failure modes were analyzed under scanning electron microscopy. Results: Push-out strength was not significantly influenced by the luting agent (p>0.05). No statistically significant differences among the tested groups were found as Group 1 (Exp 1 - ethanol-wet bonding technique)=Group 2 (Exp 2 - ethanol-wet bonding technique)= Group 3 (OSP - ethanol-wet bonding technique)= Group 4 (control, OSP - water-wet bonding technique) (p>0.05). The dominating failure modes in all the groups were cohesive/adhesive failures, which were predominantly observed on the post/luting agent interface. Conclusions: The results of this study support the hypothesis that the proposal to replace water with ethanol to bond fiber posts to the root canal using highly hydrophobic resin is plausible, but this seems to be more the proof of a concept than a clinically applicable procedure.

Efficacy of NiTi rotary instruments in removing calcium hydroxide dressing residues from root canal walls

The aim of this study was to evaluate the efficacy of three rotary instrument systems (K3, Pro Taper and Twisted File) in removing calcium hydroxide residues from root canal walls. Thirty-four human mandibular incisors were instrumented with the Pro Taper System up to the F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA, and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments: G1. - NiTi size 25, 0.06 taper, of the K3 System; G2 - NiTi F2, of the Pro Taper System; or G3 - NiTi size 25, 0.06 taper, of the Twisted File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (x1000). The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05).

Evaluation of epoxy resin sealer after three root canal filling techniques by confocal laser scanning microscopy

The aim of this study was to evaluate the penetration of endodontic sealer into the dentin tubules, the integrity of the sealer layer perimeter, and the sealer area at the apical third after different filling techniques by confocal laser scanning microscopy (CLSM). Forty-five mandibular premolars were mechanically prepared with ProTaper files, until F5 file. Thereafter, they were filled with an epoxy-resin sealer (AH Plus) mixed with Rhodamine B dye (0.1% proportion) and allocated in three groups: Group 1, single master cone; Group 2, cold lateral compaction; and Group 3, Thermafil. For confocal laser scanning microscopy analysis, the specimens were transversely sectioned at 4 mm from the apex. The images at x10 and x40 were analyzed by Imagetool 3.0 software. Significant differences were not found among the three experimental groups according the dentin-impregnate area by the sealer (P = 0.68) and between the sealer and root canal perimeter (P = 0.18). However, root canal filling techniques were significantly different when apical sealer areas were compared (P = 0.001). Thermafil group showed smaller sealer areas (8.09%) while cold lateral compaction and gutta-percha master cone showed similar areas (17.37 and 21.18%, respectively). The dentin-impregnated area was not dependent on the root canal filling technique. Single master cone, cold lateral condensation and Thermafil techniques presented integrity of the sealer perimeter close to 100% and Thermafil resulted in a significantly thinner sealer layer. Microsc. Res. Tech. 75:12771280, 2012. (C) 2012 Wiley Periodicals, Inc.

The antimicrobial effects of root canal irrigation and medication

The role of microorganisms in the development and maintenance of pulpal and periapical inflammation have been well documented. The success of root canal treatment largely depends on the elimination of microbial contamination from the root canal system. Although mechanical instrumentation of root canals can reduce bacterial population, effective elimination of bacteria cannot be achieved without the use of antimicrobial root canal irrigation and medication. This review will discuss the antimicrobial effects of the known root canal irrigants and medicaments and explore future developments in the field. © 2007 Mosby, Inc. All rights reserved.

Matrix Metalloproteinase Expression in Teeth with Apical Periodontitis Is Differentially Modulated by the Modality of Root Canal Treatment

Introduction: The objective of this study was to investigate the expression of matrix metalloproteinases (MM Ps) in apical periodontitis and during the periapical healing phase after root canal treatment. Methods: Apical periodontitis was induced in dog teeth, and root canal treatment was performed in a single visit or by using an additional calcium hydroxide root canal dressing. One hundred eighty days after treatment the presence of inflammation was examined, and tissues were stained to detect bacteria. Bacterial status was correlated to the degree of tissue organization, and to further investigate molecules involved in this process, tissues were stained for MMP-1, MMP-2, MMP-8, and MMP-9. Data were analyzed by using one-way analysis of variance followed by Tukey test or Kruskal-Wallis followed by Dunn test. Results: Teeth with apical periodontitis that had root canal therapy performed in a single visit presented an intense inflammatory cell infiltrate. Periapical tissue was extremely disorganized, and this was correlated with the presence of bacteria. Higher MMP expression was evident, similar to teeth with untreated apical periodontitis. In contrast, teeth with apical periodontitis submitted to root canal treatment with calcium hydroxide presented a lower inflammatory cell infiltrate. This group had moderately organized connective tissue, lower prevalence of bacteria, and lower number of MMP-positive cells, similar to healthy teeth submitted to treatment. Conclusions: Teeth treated with calcium hydroxide root canal dressing exhibited a lower percentage of bacterial contamination, a lower MMP expression, and a more organized extracellular matrix, unlike those treated in a single visit. This suggests that calcium hydroxide might be beneficial in tissue repair processes. (J Endod 2010;36:231-237)

Apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing on root canal disinfection in dog teeth

Objective. The aim of this study was to compare in vivo the efficacy of 2 root canal disinfection techniques (apical negative pressure irrigation versus apical positive pressure irrigation plus triantibiotic intracanal dressing) in immature dog teeth with apical periodontitis. Study design. Two groups of root canals with pulp necrosis and apical periodontitis were evaluated according to the disinfection technique: group 1: apical negative pressure irrigation (EndoVac system); and group 2: apical positive pressure irrigation (conventional irrigation) plus triantibiotic intracanal dressing. The first sample (S1) was collected after lesions were radiographically visible, and the second sample (S2) was collected after apical negative pressure irrigation (group 1) or conventional irrigation/triantibiotic dressing (group 2). All samples were seeded in a culture medium for anaerobic bacteria. Colony-forming unit counts were analyzed statistically by the Mann-Whitney test (alpha = .05). Results. Microorganisms were present in 100% of canals of both groups in S1. In S2, microorganisms were absent in 88.6% of group 1`s canals and 78.28% of group 2`s canals. There was no significant difference between the groups in either S1 (P = .0963) or S2 (P = .0566). There was significant (P < .05) bacterial reduction from S1 to S2 in both groups. Conclusion. In immature teeth with apical periodontitis, use of the EndoVac system can be considered to be a promising disinfection protocol, because it provided similar bacterial reduction to that of apical positive pressure irrigation (conventional irrigation) plus intracanal dressing with the triantibiotic paste, and the use of intracanal antibiotics might not be necessary. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:e42-e46)

Tissue damage after sodium hypochlorite extrusion during root canal treatment

Sodium hypochlorite solution is toxic to vital tissues, causing severe effects if extruded during endodontic treatment. This paper presents a report on the tissue damage related to inadvertent extrusion of concentrated sodium hypochlorite solution during root canal treatment. A 65-year-old woman was referred with moderate pain, ecchymosis, and severe swelling of the right side of the face. These symptoms appeared immediately after a root canal treatment of the maxillary right canine, which had been started 21 hours earlier. It was diagnosed as air emphysema related to sodium hypochlorite solution extravasation during the endodontic treatment. To avoid this, an initial radiograph should be taken to determine the correct canal working length and confirm root canal integrity. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: e46-e49)

Outcome of Root Canal Treatment in Dogs Determined by Periapical Radiography and Cone-Beam Computed Tomography Scans

The purpose of this study was to compare the favorable outcome of root canal treatment determined by periapical radiographs (PRs) and cone beam computed tomography (CBCT) scans. Ninety-six roots of dogs` teeth were used to form four groups (n = 24). In group 1, root canal treatments were performed in healthy teeth. Root canals in groups 2 through 4 were infected until apical periodontitis (AP) was radiographically confirmed. Roots with AP were treated by one-visit therapy in group 2, by two-visit therapy in group 3, and left untreated in group 4. The radiolucent area in the PRs and the volume of CBCT-scanned periapical lesions were measured before and 6 months after the treatment. In groups 1, 2, and 3, a favorable outcome (lesions absent or reduced) was shown in 57 (79%) roots using PRs but only in 25 (35%) roots using CBCT scans (p = 0.0001). Unfavorable outcomes occurred more frequently after one-visit therapy than two-visit therapy when determined by CBCT scans (p = 0.023). (J Endod 2009; 35:723-726)

Preliminary study of the inflammatory response to subcutaneous implantation of three root canal sealers

P>Aim To evaluate the kinetics of the inflammatory tissue response to three root canal sealers using a physicochemical method for quantification of the enhanced vascular permeability and histopathological analysis. Methodology Twenty-eight male Wistar rats randomly assigned to four groups according to the evaluation periods (1, 3, 7 and 14 days) were used to assess the vascular permeability and histopathological reaction to RoekoSeal, AH Plus and Sealapex (new formulation) sealers, using saline and Chloropercha as negative and positive controls, respectively. Seven rats were sacrificed per period. The biocompatibility of the sealers was evaluated spectrophotometrically and histopathologically. Results At day 14, Sealapex produced significantly more inflammatory exudate than AH Plus and RoekoSeal (P < 0.05); however, there was no significant difference between AH Plus and RoekoSeal (P > 0.05). Sealapex (new formulation) was the most irritating sealer, producing severe inflammation with the presence of multinucleated giant cells. RoekoSeal was the most biocompatible sealer, producing the least amount of inflammatory exudate. Conclusions RoekoSeal root canal sealer was biocompatible when implanted in connective tissue.