Removal of the root canal smear layer using Carisolv III and sodium hypochlorite.

The present study investigated the effectiveness of a Carisolv III + 0.5% sodium hypochlorite (NaOCl)-based root canal irrigant for smear layer removal.Forty maxillary incisors were randomly divided into 4 groups (n = 10 per group). The canals in group A (experimental) were prepared with 0.5% NaOCl, and Carisolv III and 0.5% NaOCl was used for the final washing; groups B and C (positive controls) used 2% and 5.25% NaOCl, respectively; and group D (negative control) used phosphate-buffered saline (PBS). Ethylenediaminetetraacetic acid (EDTA) was used for all of the groups. A 5-point scoring scale and scanning electron microscopy were used to evaluate the effectiveness of the irrigants. The canals were consistently cleaner in the coronal and middle thirds than in the apical thirds (P < .05).For cleaning the root canals, 5.25% NaOCl was more effective than 2% NaOCl, 0.5% NaOCl + Carisolv III, and phosphate-buffered saline , respectively (P < .05). The 2% NaOCl solution showed similar results to 0.5% NaOCl + Carisolv III (P > .05). The combination of 5.25% NaOCl and 17% EDTA remains the most effective irrigant for removal of the root canal smear layer.A combination of Carisolv III + 0.5% NaOCl (with 17% EDTA) showed a cleaning ability similar to that of 2% NaOCl (with 17% EDTA).

Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA.

Laser-induced agitation and cavitation from proprietary honeycomb tips for endodontic applications.

Cavitation and agitation generated by lasers in fluid-filled root canals create fluid movement and shear stresses along the root canals walls, enhancing removal of the smear layer and biofilm. When used with sodium hypochlorite and EDTA, laser activation of aqueous fluids can increase the efficiency of debridement and disinfection of root canals. However, the use of forward-firing laser fibers with such solutions poses a risk of driving fluid past the root apex, which could cause postoperative complications. The purpose of this study was to evaluate the mechanism of fluid agitation caused by a novel honeycomb tip. Glass capillary tubes filled with distilled water were used to replicate single-tooth root canals. A 980 nm pulsed diode laser was used with 200 µm diameter plain tips, tube-etched conical tips, and honeycomb tips. To record fluid movements, the tubes were backlit and imaged using a digital camera attached to a microscope. The honeycomb tips generated agitation with fluid movement directed onto the walls, while both the conventional plain fibers and the conical tips created fluid movement largely in a forward direction. The use of honeycomb tips alters the pattern of fluid agitation, and this laterally directed effect might lower the risk of fluid extrusion beyond the apex.

MTAD in endodontics: an update review.

The major objective in endodontic therapy is to achieve complete chemomechanical debridement of the entire root canal system. This can be accomplished with biomechanical instrumentation and chemical irrigation. Various endodontic irrigants, such as sodium hypochlorite, chlorhexidene, and iodine potassium iodide, are available, each having its own advantages with some limitations. MTAD, a new endodontic irrigant, has been introduced to fulfill these limitations. MTAD is a mixture of doxycycline, citric acid, and a detergent (Tween 80). Since its introduction, it is a material that has been researched extensively for its properties. This article presents a review on the numerous properties of MTAD, such as antimicrobial activity, smear layer- and pulp-dissolving capability, effect on dentin and adhesion, and biocompatibility.

Effectiveness of the EndoActivator System in removing the smear layer after root canal instrumentation.

INTRODUCTION: Elimination of the smear layer after root canal instrumentation requires the use of irrigating solutions. This cleaning can be completed with passive ultrasonic or sonic irrigation. The aim of this study was to evaluate the effectiveness of the EndoActivator System in removing the smear layer after rotary root canal instrumentation, with and without a final flush of 17% ethylenediaminetetraacetic acid (EDTA) solution, in coronal, middle, and apical thirds. METHODS: Forty single-canal teeth were decoronated and randomly divided into 4 groups (n = 10). The groups were instrumented by using Mtwo System. EndoActivator was used with a final rinse of 1 mL of 17% EDTA or 4% NaOCl for 1 minute. The roots were longitudinally split and were grooved in the coronal, middle, and apical thirds. Scanning electron microscopy digital photomicrographs at 400x were taken to evaluate the amount of smear layer in each third. RESULTS: The NaOCl/EndoActivator group did not remove any smear layer of the root canal wall (100% in the coronal, middle, and apical thirds). In the groups that used 17% EDTA (with or without EndoActivator), the smear layer was eliminated completely (100%) in the coronal third, but the amount of removal was less in the other two thirds. The comparisons between NaOCl versus NaOCl/EndoActivator groups and EDTA/NaOCl versus EDTA/EndoActivator/NaOCl groups showed no significant differences in root canal thirds. CONCLUSIONS: The EndoActivator System did not enhance the removal of smear layer as compared with conventional Max-I-Probe irrigation with NaOCl and EDTA.

One-appointment endodontic therapy: biological considerations.

BACKGROUND: The authors conducted a literature review to present the best available biological evidence concerning one-appointment endodontic therapy for asymptomatic teeth with apical periodontitis. TYPES OF STUDIES REVIEWED: Because of recent advances in technology, such as rotary engines and nickel-titanium instruments, some practitioners are performing one-appointment endodontic therapy for asymptomatic teeth with apical periodontitis. The authors reviewed the literature, which revealed only a small number of randomized, controlled clinical trials that have been conducted on one-appointment versus multiple-appointment endodontic therapy. RESULTS: As the apical canal preparation is enlarged, a greater percentage of bacteria is eradicated from infected root canals. In addition, sufficiently large apical root canal enlargement facilitates the delivery of antimicrobial irrigant to the apical portion of the canal. However, an association between positive or negative preobturation root canal culture results and the outcome of endodontic treatment has not been well-established. CLINICAL IMPLICATIONS: The best available evidence, based on a systematic literature review, indicates that one-appointment endodontic therapy may be feasible in selected cases of apical periodontitis in asymptomatic teeth. However, additional randomized, controlled clinical trials are required.

Evaluation of healing with use of an internal matrix to repair furcation perforations.

AIM: The purpose of this study was to evaluate healing responses following repair of furcation perforations, with and without an internal matrix. Two matrix materials, HAPSET (65% non-resorbable hydroxyapatite and 35% plaster of paris) and hydroxyapatite were compared. METHODOLOGY: Four adult female baboons (Papio anubis) served as experimental models. Furcation perforations were made in the molar and premolar teeth, which were then randomly assigned to one of the five groups, according to the method of perforation repair: 1 Experimental group 1 (16 teeth): The matrix material was HAPSET and the sealing material, amalgam. 2 Experimental group 2 (16 teeth): The matrix material was hydroxyapatite and the sealing material, amalgam. 3 Experimental group 3 (16 teeth): No matrix was placed. The sealing material was amalgam. 4 Positive control group (16 teeth): The perforation was not sealed. 5 Negative control group (16 teeth): No perforation was made. The animals were sacrificed at 1 week and 1, 3 and 7 months. Specimens were prepared for examination with light microscopy. RESULTS: The data revealed that when amalgam was used alone without a matrix, there was marked extrusion of the material into the underlying bone with an associated severe inflammatory response, which continued throughout the observational period. When an internal matrix was used, there was an initial acute inflammatory response that diminished with time such that at 7 months, 75% of these specimens were free of inflammation. There was no difference in the tissue response to the different matrix materials. HAPSET and hydroxyapatite underwent connective tissue encapsulation in the early stages followed by new bone deposition in direct contact with the materials. CONCLUSIONS: Within this animal model healing responses are better when an internal matrix, whether HAPSET or hydroxyapatite, is used in the repair of furcation perforations.