Influence of size and insertion depth of irrigation needle on debris extrusion and sealer penetration.

OBJECTIVES: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). MATERIALS AND METHODS: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. RESULTS: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). CONCLUSIONS: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.

The effect of N-acetylcysteine and calcium hydroxide on TNF-α and TGF-ß1 in lipopolysaccharide-activated macrophages.

OBJECTIVE: The present study was designed to evaluate the pro- and anti-inflammatory effects of NAC and calcium hydroxide (Ca(OH)2) on lipopolysaccharide-stimulated human macrophage cell lines. DESIGN: THP-1 human monocyte precursor cells were differentiated into macrophage adherent cells. Cell cytotoxicity was measured by flow cytometry analysis. NAC and Ca(OH)2 were applied in the presence or absence of lipopolysaccharides (LPS) for time periods of 4, 8, and 24h. Protein and mRNA levels of tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta1 (TGF-ß1) were determined using ELISA and qRT-PCR. The data were statistically analyzed by three-way ANOVA followed by Bonferroni test at α=0.05. RESULTS: In LPS-stimulated cell lines, while the TNF-α protein and mRNA levels were reduced in the first 4h, only the TGF-ß1 mRNA levels increased in the 24th hour following treatment with Ca(OH)2 and NAC when compared with the control group (p<0.001). In LPS-unstimulated cells, the TNF-α protein level was significantly decreased by NAC and Ca(OH)2 at the 4th hour. Additionally, while the TGF-ß1 mRNA levels were significantly reduced, the protein level of TGF-ß1 was increased at the 24th hour. CONCLUSIONS: It was concluded that NAC, similar to Ca(OH)2, has anti-inflammatory properties and might be considered an alternate candidate therapeutical agent to Ca(OH)2.

Evaluation of the Bond Strength and Fracture Resistance of Different Post Systems.

AIM: To compare the bond strength and the fracture resistance of different post systems. MATERIALS AND METHODS: Endodontically treated 60 mandibular incisor and 60 mandibular premolar teeth were used for the bond strength and fracture resistance test respectively. For each test, three groups (n = 20) were formed according to the posts used zirconia posts (ZR post), individually formed glass fiber reinforced composite posts with an (Interpenetrating Polymer Network-IPN post) and cast metal posts. Then groups were randomly assigned into two subgroups according to the post design: 1-parallel sided and 2-tapered (n = 10/group). All posts were luted with a self-adhesive luting agent. For push-out test two 1 mm thick horizontal root sections were obtained and subjected to push-out test. For fracture resistance test, the specimens were loaded vertically at 1 mm/min crosshead speed. The push out test data were analyzed with Kruskal-Wallis and Dunn's test. Analysis of variance (ANOVA) and Tukey significant difference tests were used to compare the fracture resistance. RESULTS: Cast metal posts showed the highest retention (p < 0.05); however, IPN and zirconia posts showed similar results. No significant difference was found between parallel sided or tapered designs of post groups in terms of bond strength (p > 0.05). In terms of fracture resistance, IPN post groups showed lowest fracture resistance (p < 0.05). No significant difference was found between parallel sided or tapered posts in terms of fracture resistance, except zirconia post (p > 0.05). There was no relationship between the bond strength and fracture resistance of the post systems (r = - 0.015, p > 0.700). CONCLUSION: Post type had effect both on the fracture resistance and retention of the posts used. However, post design had effect only on the fracture resistance of the post systems. CLINICAL SIGNIFICANCE: Superficial treatment of the post used can improve the retention of post systems.

Antimicrobial and structural effects of different irrigation solutions on gutta-percha cones.

PURPOSE: To evaluate the alterations on the surface of gutta-percha cones (GPCs) on exposure to the different irrigation solutions and their possible antibacterial effect against Enterococcus faecalis. (E. faecalis). MATERIALS AND METHODS: Disinfection ability of different solutions (5.25% sodium hypochlorite, 2% chlorhexidine, 1% peracetic acid, and QMix) were tested with 96 GPCs and the time of exposure to each solution was 5 and 10 minutes, respectively. GPCs used in this study were contaminated with E.faecalis. After disinfection, GPCs were placed in tubes containing the medium and incubated at 37˚C for 7 days. All tubes were visually checked for turbidity at 24-hour intervals. About 92 new GPCs were analyzed by means of SEM/EDS to assess the topography and chemical elements present on their surface. The data generated was analyzed using Pearson chi-square test, p<0.05. RESULTS: There were no significant statistical differences in disinfection quality between the irrigation solutions used on GPCs contaminated with E. faecalis (p>0.05). SEM/EDS analyses showed no alteration in the superficial features of GPCs after treating with various irrigation solutions. CONCLUSION: QMix was found to be an effective agent for rapid disinfection of GPCs as well-known irrigation solutions. Irrigation solutions were found to have sterilized the GPCs after both 5 and 10 minutes of exposure.

The effectiveness of a pictorial asthma action plan for improving asthma control and the quality of life in illiterate women.

BACKGROUND: Written asthma action plans are an important part of asthma management, but cannot be used for illiterate people. OBJECTIVE: The aim of this study was to establish the effectiveness of a pictorial asthma action plan on asthma control, health-related quality of life (HRQoL), and asthma morbidity in a population of illiterate women with asthma. METHODS: Forty illiterate women with moderate-severe persistent asthma were assigned alternatively to receive either asthma education alone (control group) or asthma education and a pictorial asthma action plan (study group). Asthma control was assessed using the asthma control test (ACT), HRQoL was assessed using the St George's Respiratory Questionnaire (SGRQ), and the frequency of non-scheduled hospital or emergency visits was monitored. RESULTS: Thirty-four patients completed the study. The ACT and SGRQ scores of both groups improved at every follow-up time point compared with baseline (p < 0.001). The ACT scores at 1 month (22.44 versus 20.75, p = 0.034) and 2 months (23.28 versus 21.81, p = 0.010) were higher in the study group than in the control group, but this was not maintained at 6 months (24.00 versus 23.25, p = 0.069). The SGRQ scores at 6 months were better in the study group (18.12) than in the control group (23.96, p = 0.033). No hospital admissions were recorded for either group. CONCLUSION: Education provides a significant improvement in asthma control and HRQoL while managing illiterate asthma patients, additionally the pictorial asthma action plan can be a helpful tool for self-medication.

Efficacy of rotary Ni-Ti retreatment systems in root canals filled with a new warm vertical compaction technique.

The aim of this study was to compare the efficacy of Mtwo, ProTaper retreatment files and Hedström files for the retreatment of root canals filled with BeeFill 2 in1 and cold lateral compaction techniques. 63 single-rooted human teeth were prepared with Mtwo rotary files to size 35/.04 and assigned into three groups (n=21/group). (1) BeeFill 2 in1/2Seal, (2) BeeFill 2 in1/AH26 and (3) laterally-compacted gutta-percha/AH26. The specimens were subgrouped according to the file system used to remove root fillings (n=7/subgroup): 1. Mtwo retreatment file, 2. ProTaper retreatment file, 3. Hedström file. Roots were split longitudinally and photographed. The time required for removal of root canal fillings and the areas of residual root filling materials were compared statistically (p<0.05). The maximum amount of remnant was observed in the Mtwo group for removal of BeeFill 2 in1/AH26. ProTaper retreatment files required less time to remove root filling material than Mtwo retreatment files and Hedström files (p<0.05). Among the tested removal systems, ProTaper retreatment files may offer the best efficiency-speed combination.

Bilateral palatal talon cusps on permanent maxillary lateral incisors: a case report.

Talon cusp is a rare developmental extra cusp-like projection on the cingulum area of affected anterior teeth that may cause various functional and aesthetic problems. The present report describes a case of bilateral palatal talon cusps on permanent maxillary incisors and the treatment procedure to overcome the clinical problems associated with talon cusps.

Sealing efficiency of BeeFill 2in1 and System B/Obtura II versus single-cone and cold lateral compaction techniques.

OBJECTIVE: The objective of this study was to investigate the sealing properties of 2 warm vertical compaction techniques (BeeFill 2in1, System B/Obtura II) in comparison with single-cone and cold laterally compacted gutta-percha. STUDY DESIGN: The root canals of single-rooted human teeth were prepared by using Mtwo rotary files and divided into 4 groups (n = 10/group) with respect to the filling technique tested: Group 1, cold laterally compacted gutta-percha + AH-26; Group 2, single-cone tapered Mtwo gutta-percha + AH-26; Group 3, System B/ObturaII + AH-26; Group 4, BeeFill 2in1 + 2seal. The leakage of specimens was measured using a fluid-filtration method after 1 and 2 weeks. The data were analyzed statistically with 2-way repeated measures ANOVA (P = .05). RESULTS: After 1 week, the System B/Obtura II group showed the greatest amount of leakage(P < .05) compared with the other test groups that had similar levels of fluid conductance(P < .05). By the end of the second week, the BeeFill group yielded the greatest amount of leakage (P < .05). Compared with their 1-week values, the fluid conductance of all test groups decreased significantly (P < .05). CONCLUSION: The apical sealing efficiency of System B/Obtura II and BeeFill were inferior to the other obturation techniques after 2-week fluid conductance testing in vitro.

Calcium ion diffusion from mineral trioxide aggregate through simulated root resorption defects.

The purpose of this study was to investigate the diffusion of calcium ions (Ca+2) through exposed dentinal tubules following intracanal application of mineral trioxide aggregate (MTA). Fifty-two single-rooted teeth were instrumented using 2.5% sodium hypochlorite for irrigation between each file size. Thereafter, standardized defects were created on the root surfaces so as to mimic external root resorption. The root canals and external defects received a final irrigation of 17% ethylenediaminetetraacetic acid and distilled water. MTA powder was then mixed with saline and placed into the canals. All root surfaces except the cavities were sealed with two coats of varnish. Teeth with unfilled canals (n = 26) served as controls. The teeth were immersed in saline after which the release of Ca+2 from the defects into the saline was measured at 1, 3, 7, 14, and 28 days. The results showed diffusion of Ca+2 through the defects in the dentin in MTA-filled roots with a significant increase in concentration within time.

Sealing properties of different obturation systems applied over apically fractured rotary nickel-titanium files.

This study investigated the sealing properties of cold laterally compacted gutta percha and Thermafil applied over different apically fractured rotary nickel-titanium files. Extracted human premolars were prepared by using ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland) or ProFile (Dentsply-Maillefer) systems (n = 40 for each), after which half of the specimens in each subgroup were subjected to instrument separation at the apical level. For each rotary system, roots with and without apically separated instruments (n = 10 for each) were filled with the two obturation systems and the levels of fluid conductance were recorded. In the absence of instrument separation, the leakage of Thermafil (Dentsply Maillefer) was significantly less than that achieved with cold lateral compaction (p < 0.05), whereas Thermafil yielded similar amounts of leakage in roots prepared with the ProTaper and ProFile systems (p < 0.05). Roots with fractured ProTaper instruments displayed significantly less leakage than those filled without ProTaper fragments, regardless of the obturation technique used (p < 0.05). However, intracanal separation of ProFile instruments increased the leakage (p < 0.05), but the obturation method did not influence fluid conduction (p > 0.05). These results reveal the variability of leakage associated with apically fractured ProFile and ProTaper files and different obturation methods used.

Ultramorphological and histochemical changes after ER,CR:YSGG laser irradiation and two different irrigation regimes.

The purpose of this study was to evaluate the ultramorphological and chemical changes in Er,Cr:YSGG laser-treated radicular dentin in comparison with two different irrigation regimes. Extracted human premolars were assigned into three experimental groups. Group 1: After each file size, root canals were irrigated with 5.25% NaOCL, followed by a final irrigation with 5.25% NaOCL. Group 2: At each file size, biomechanical preparation was performed in conjunction with Rc-Prep, followed by 5.25% NaOCL irrigation; and 5.25% NaOCL for the final flush. Group 3: 5.25% NaOCL was used after each file size, followed by Er,Cr:YSGG laser irradiation; and a final flush with 5.25% NaOCL. Scanning electron microscopic (SEM) evaluations revealed failure of smear removal in NaOCL-irrigated specimens. RC-Prep + NaOCL-treated dentin revealed moderate-to-total presence of the smear layer with distinct areas of exposed collagen. Er,Cr:YSGG laser irradiation of radicular dentin also resulted in partial or total removal of the smear associated with a few small regions of thermal injury, including carbonization and partial melting. Energy dispersive X-ray analysis (SEM-EDX) showed no significant difference between the Ca/P ratios of the test groups, suggesting absence of changes at the molecular level.