Significant Difference In Leakage Research Articles

Propensity-score-matched analysis of a multi-institutional dataset to compare postoperative complications between Billroth I and Roux-en-Y reconstructions after distal gastrectomy.

Few well-controlled studies have compared postoperative complications between Billroth I (B-I) and Roux-en-Y (R-Y). The aim of the present study was to compare the incidence of overall and severe postoperative complications by reconstruction method after distal gastrectomy. We performed a multi-institutional dataset study of patients who underwent distal gastrectomy with B-I or R-Y reconstruction from 2010 to 2014. Using propensity scores to strictly balance the significant variables, we compared postoperative complications between the techniques. After matching, we enrolled 1014 patients (n = 507 in each group). The incidence of postoperative complications in the R-Y group was significantly higher vs the B-I group (29% vs 17%, P < 0.0001). The incidence of intra-abdominal abscess (4.3% vs 1.8%, P = 0.0177), bowel obstruction (2.6% vs 0.6%, P = 0.0203), and delayed gastric emptying (5.3% vs 1.0%, P < 0.0001) in the R-Y group was significantly higher vs the B-I group, respectively; we saw no significant difference in leakage (3.4% vs 4.1%, P = 0.5084). The incidence of grade ≥ III severe postoperative complications in the R-Y group was significantly higher vs the B-I group (13% vs 7.1%, P = 0.0013). Multivariable analysis showed that R-Y reconstruction was a strong independent risk factor for overall postoperative complications (odds ratio 1.58, P = 0.0044) and grade ≥ III severe postoperative complications (odds ratio 1.75, P = 0.0127). A forest plot revealed that R-Y reconstruction was associated with a greater risk of both overall and grade ≥ III severe postoperative complications in any subgroups. R-Y reconstruction was associated with increasing overall postoperative complications, as well as severe postoperative complications.

Propensity-score-matched analysis of a multi-institutional dataset to compare the postoperative complications after distal gastrectomy between Billroth I and Roux-en-Y.

292 Background: Billroth I (B-I) or Roux-en-Y (R-Y) are common reconstruction technique after distal gastrectomy, each with advantages and disadvantages and which is the most successful remains unclear. The aim of the present study was to clarify the difference of postoperative complications between the two techniques. Methods: A multi‐institutional retrospective database comprising clinical information of 3484 patients who received resection of gastric cancer from 2010 to 2014 at nine institutions. Using propensity scores to strictly balance the significant variables, and we compared the overall and severity postoperative complications. We considered Clavien–Dindo grade ≥ II postoperative complications clinically relevant, and grade ≥ III severe postoperative complications. Results: After matching, we enrolled 1086 patients (n=543 in each group). The incidence of postoperative complications in the R-Y group was significantly higher vs the B-I group (28% vs 17%, respectively; P&lt;0.0001). The incidence of intra-abdominal abscess (4.2% vs 1.7%, P=0.0120), pancreatic fluid leakage (3.1% vs 1.1%, P=0.0204), bowel obstruction (2.8% vs 0.7%, P=0.0109), and delayed gastric emptying (5.0%s 0.9%, P&lt;0.0001) in the R-Y group was significantly higher vs the B-Ⅰ group, respectively; but not significant difference in leakage (3.2% vs 3.3%, respectively; P=0.8636). The incidence of severe postoperative complications in the R-Y group was also significantly higher vs the B-I group (15% vs 6.3%, respectively; P&lt;0.0001). Multivariable analysis for severe postoperative complications found that R-Y reconstruction was an independent risk factor (odds ratio, 2.20, P=0.0005). Subgroup analysis found that R-Y reconstruction was associated with a greater risk of severe postoperative complications in most subgroups, but not the subgroup of patients receiving intraoperative transfusions. Conclusions: R-Y reconstruction was associated with increasing overall postoperative complications, as well as grade ≥ III severe postoperative complications.

Cinnamon and clove oil nanoemulsions: novel therapeutic options against vancomycin intermediate susceptible Staphylococcus aureus

Antibiotic resistance is one of the most important public health concerns worldwide. Essential oils especially as micro- and nanoemulsion formulations are emerging as potential agents to target resistant pathogens and as drug delivery vehicles. Cinnamon and clove oils were formulated into nanoemulsions using Brij 35 or Tween 20. Based on the physicochemical characteristics and stability, CiB-3, ClB-3, CiT20-5 and ClT20-5 were identified as optimised emulsions and their anti-Staphylococcal properties were determined. Hydrodynamic diameter of the oil droplets was < 15 nm. The emulsions have only 5% of oil, and there was an 83–166-fold improvement in static MIC over the bulk oil. Inocula ranging from 105 to 107 CFU mL−1 of both MSSA and VISA strains did not significantly affect the activity of all four nanoemulsions. Tween 20 containing nanoemulsions had higher anti-biofilm activity (66–76%) and the activity was comparable between MSSA and VISA. ClT20-5 decreased the viable counts of both strains below detectable limits by 24 h. There was a statistically significant difference in leakage of 260-nm-absorbing cellular components between MSSA and VISA at 30 min (CiB-3: P = 4.67e−013, ClB-3: P = 2.49e−010, CiT20-5: P = 0.00028, ClT20-5: P = 0.00056) and at 60 min (CiB-3: P = 1.37e−014, ClB-3: P = 4.14e−014, CiT20-5: P = 5.30e−012, ClT20-5: P = 2.82e−009). The SEM images of the treated and untreated cells show significant damage and alteration in the morphology of the emulsion treated cells. This study demonstrates the significant anti-Staphylococcal activity of cinnamon and clove oil against MSSA and VISA strains.

Comparative Study of the Effect on Apical Sealability with Different Levels of Remaining Gutta-Percha in Teeth Prepared to Receive Posts: An in vitro Study.

Objective:The objective of this study is to compare the apical sealability of mineral trioxide aggregate (MTA) Fillapex and Endosequence BC sealer at three different lengths of remaining gutta-percha after postspace preparation.Materials and Methods:A total of 80 freshly extracted human maxillary anterior teeth were decoronated, biomechanically prepared, and randomly divided into four groups; Group A and Group B served as positive and negative control with 10 teeth each. The teeth in Group C and Group D (with 30 teeth each) were obturated with gutta-percha using MTA Fillapex sealer and Endosequence BC sealer, respectively. Teeth in Group C and Group D were further subdivided into three subgroups depending on the length of remaining apical gutta-percha, i.e., 3, 4, and 5 mm after postspace preparation. Apical leakage was assessed using dye penetration method under stereomicroscope.Results:In both the Groups C and D, there was overall no statistically significant difference in leakage; however, Group C showed slightly more leakage than Group D. There was a statistically significant difference in leakage at 3 mm and 5 mm level in both groups.Conclusion:Although less microleakage occurred, the bioceramic sealers could not totally eliminate leakage.

Postoperative urinary symptoms after transobturator tape in normal-weight compared with overweight and obese woman.

ObjectivesTo examine the clinical outcome of obesity in women who underwent the transobturator tape procedure for stress urinary incontinence and to compare postoperative urinary symptoms after transobturator tape surgery between normal-weight women and overweight and obese women.MethodsWe performed a retrospective cohort study of the risk of postoperative urinary symptoms, including recurrence after transobturator tape surgery, in normal-weight women compared with overweight and obese women at our institution from January 2009 through October 2011. We compared the body mass index (BMI) among the four groups. The primary outcome was the occurrence of postoperative urinary symptoms.ResultsThree hundred ten patients who underwent transobturator tape surgery were reviewed. At the 1-year follow-up, 281 women were analyzed: 89 (34%) normal-weight women, 78 (25%) overweight women, 101 (37%) obese 1 women, and 13 (3%) obese 2 women. There was a significant difference in the occurrence of postoperative urinary symptoms. They occurred in 3.4% (n=3) of normal-weight women, 5.1% (n=4) of overweight women, and 12.9% (n=13) of obese 1 women (P=0.038). The most common postoperative urinary symptom was frequent urination (n=14). There was a significant difference in leakage; it occurred in 1.1% (n=1) of normal-weight women, 3.9% (n=3) of overweight women, and 7.9% (n=8) of obese 1 women (P=0.139). Postoperative urinary symptoms were almost four times more likely to occur in obese 1 women than in normal-weight women.ConclusionTransobturator tape surgery seems effective regardless of BMI, but obese women had a higher occurrence of postoperative urinary symptoms than did normal-weight women.

Modified Double-Layer Anastomosis for Minimally Invasive Esophagectomy: An Effective Way to Prevent Leakage and Stricture.

Anastomotic leakage and stricture contribute to a large number of mortality and morbidity after esophagectomy. The aim of this work is to evaluate the outcome of modified double-layer hand-sewn esophagogastric anastomosis during minimally invasive esophagectomy for esophageal cancer. The clinicopathological data of 176 consecutive esophageal cancer patients who underwent cervical esophagogastric anastomosis using modified double-layer hand-sewn technique after radical esophagectomy were retrospectively reviewed. Total minimally invasive approach, including thoracoscopic surgery for thoracic procedure and laparoscopic approach for abdominal procedure, was implemented during the radical Mckeown esophagectomy. Patients were followed up for the assessment of postoperative anastomotic complications including anastomotic leakage and stricture, being the primary outcome measures for this study. Anastomotic leakage occurred in 2 of 176 patients (1.1%); both of the patients experienced only minor leakage and were treated conservatively. There was no significant difference in leakage between patients with and without major comorbidity (p=0.331). After a mean follow-up of 21.3months, four patients (4/176, 2.3%) developed benign anastomotic strictures, including those 2 patients experienced postoperative leakage. Symptoms for stricture were improved by endoscopic dilatations in all 4 patients. Besides, there was one case (1/176, 0.6%) of gastric necrosis in this cohort, who was also successfully managed by conservative therapy with no operative mortality. This modified double-layer hand-sewn anastomosis is a highly safe and stable technique for esophagogastrostomy, which is an effective way to prevent both anastomotic leakage and stricture.

Intraorifice sealing ability of different materials in endodontically treated teeth: An in vitro study.

Background:Microbial contamination of the pulp space is one of the major factors associated with endodontic failure. Thus, in addition to a three dimentional apical filling a coronal seal for root canal fillings has been recommended.Aim:The present study was conducted to evaluate and compare the intra-orifice sealing ability of three experimental materials after obturation of the root canal system.Materials and Methods:Fourty single rooted mandibular premolars were decoronated, cleaned, shaped and obturated. Gutta-percha was removed to the depth of 3.5 mm from the orifice with a heated plugger. Ten specimens each were sealed with Light Cure Glass Ionomer Cement (LCGIC), Flowable Composite (Tetric N-Flow), and Light Cure Glass Ionomer Cement with Flowable Composite in Sandwich Technique along with a positive control respectively and roots submerged in Rhodamine-B dye in vacuum for one week. Specimens were longitudinally sectioned and leakage measured using a 10X stereomicroscope and graded for depth of leakage.Results:According to the results of the present study LC GIC + Tetric N Flow demonstrated significantly better seal (P < 0.01) than LC GIC. However there was no statistically significant difference in leakage (P > 0.01) between Tetric N-Flow and LCGIC+Tetric N-Flow groups.Conclusion:In the current study LCGIC+Tetric N-Flow was found to be superior over other experimental materials as intra-orifice barriers.

Comparison of outcomes according to the operation for type A esophageal atresia.

PurposeThe purpose was to evaluate outcomes according to different operative strategies of type A esophageal atresia (EA).MethodsAll patients who underwent surgery for type A EA between 1980 and 2011 were included. Patients were divided into 2 groups: E-E group included patients who received esophageal end-to-end anastomosis, whereas E-G group included patients who received esophago-gastric tube anastomosis.ResultsTwenty-two patients were included. The median gestational age was 37.5 weeks. The median birth weight was 2.5 kg. Twenty-one patients underwent gastrostomy as initial procedures, and one patient underwent primary esophageal end-to-end anastomosis. The median gap between both esophageal ends was six vertebral distance (VD). Seven patients underwent primary anastomosis of the esophagus, and 14 patients underwent gastric replacement. Three patients (13.6%) had anastomotic leakage and 10 patients (45.5%) had anastomotic stenosis. Most of the patients (90.9%) had gastroesophageal reflux, but only two patients required antireflux surgery. The median VD was significantly shorter in E-E group than in E-G group (3 VD vs. 6 VD). Stenosis was significantly more often in E-E group, but there was no significant difference in leakage and reflux symptoms.ConclusionThe treatment for type A EA can include E-E anastomosis or E-G anastomosis, depending on the length of the end-to-end interval after performing gastrostomy. Appropriate tension and blood flow in the anastomosis site are essential for preventing postoperative stenosis and leakage, and esophageal replacement with gastric tube is believed to be feasible and safe in cases where excessive tension is present.

A comparative evaluation of the sealing ability of 2 root-end filling materials: an in vitro leakage study using Enterococcus faecalis

The purpose of this study was to evaluate the sealing ability of EndoSequence Bioceramic Root-end Repair (BCRR) material when compared with white mineral trioxide aggregate (WMTA). Forty single-rooted teeth were instrumented, obturated with gutta-percha, root-end resected, and retrofilled with 2 different materials: white ProRoot MTA (WMTA) (n = 15) and BCRR (n = 15). Unfilled specimens (n = 10) received no retrofill and were used as controls. All groups received E. faecalis in a created reservoir coronal to the root filling and the presence of microleakage was evaluated by counting the colony-forming units from each specimen. The results were analyzed with 1-way analysis of variance. There was no significant difference in leakage between the 2 experimental groups, but there was a significant difference with the control (P ≤ .05). This study suggests that BCRR is equivalent in sealing ability to WMTA when used as root-end filling material in vitro.

Microleakage comparison of glass-ionomer and white mineral trioxide aggregate used as a coronal barrier in nonvital bleaching

There is some evidence that the pH at the root surface is reduced by intracoronal placement of bleaching pastes, which is known to enhance osteoclastic activity. Therefore, it is recommended that a protective barrier be used over the canal filling to prevent leakage of bleaching agents. Glass-ionomer (GI) is commonly used as a coronal barrier before nonvital bleaching. Because mineral trioxide aggregate (MTA) creates high alkalinity after mixing with water, using MTA as a protective barrier over the canal filling may not only prevent leakage of bleaching agents and microorganisms, but may prevent cervical resorption. The aim of this study was to evaluate sealing ability of white mineral trioxide aggregate (WMTA) as a coronal barrier before nonvital bleaching. Root canals of one hundred thirty human maxillary incisors were instrumented and filled with gutta-percha without sealer. Gutta-percha was removed up to 3 mm below the cementoenamel junction (CEJ). The teeth were randomly divided into six experimental groups of 20 teeth each and two control groups of 5. In three experimental groups, WMTA was packed into the canal to the level of CEJ. In the remaining experimental groups, glass-ionomer (GI) was used as a coronal barrier. After a 24-hour incubation period, one of the following three bleaching agents was placed in the access cavity of each of the WMTA or GI groups. These three bleaching agents were 30% hydrogen peroxide, sodium perborate mixed with 30% hydrogen peroxide, and sodium perborate mixed with distilled water. The bleaching agents were replaced every 3 days for three times. In the positive controls, no coronal barrier was used. In the negative controls, all the tooth surfaces were covered by two layers of nail varnish. Microleakage was evaluated using protein leakage test. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney tests. The experimental groups showed minimum leakage which was not significantly more than tha in the negative controls. There was no statistically significant difference in leakage between the experimental groups (p<0.05). This study indicated that different bleaching agents have no effect on sealing ability of WMTA.

Emissions of N2O and NH3, and nitrogen leaching from direct seeded rice under different tillage practices in central China

Tillage practices affect the fate of fertilizer nitrogen (N) through influencing transformations of N, but few studies have examined N2O and NH3 emissions, and N leaching from different rice tillage systems. Thus the objective of this study was to assess N2O emission, NH3 volatilization and N leaching from direct seeded rice in conventional tillage (CT) and no-tillage (NT) production systems in the subtropical region of China during the 2008 and 2009 rice growing seasons. Treatments were established following a split-plot design of a randomized complete block with tillage practices as the main plot and N fertilizer level as the sub-plot treatment, and there were four treatments: NT+no fertilizer (NT0), CT+no fertilizer (CT0), NT+compound fertilizer (NTC) and CT+compound fertilizer (CTC), respectively. Results showed that N fertilization significantly increased (p<0.01) N2O emissions, NH3 volatilization and N leaching from rice fields in both years. In general, there was no significant difference in N2O emissions and NH3 volatilization between NT0 and CT0 in both years, while NTC had significantly higher (p<0.05) N2O emissions and NH3 volatilization compared to CTC. Over the two rice growing seasons, NTC showed 32% and 47% higher N2O emissions, and 29% and 52% higher NH3 losses than CTC. Higher (p<0.05) N2O emissions from NTC than CTC were presumably due to higher soil organic C and greater denitrification. Total N and NO3− concentrations were higher (p<0.05) in CTC than NTC, but larger volumes of percolation water in NTC than CTC resulted in no significant difference in leakage of total N and NO3−. Hence, application of N fertilizer in combination with NT appeared to be ineffective in reducing N losses from N fertilizer in paddy fields.

Sealing Ability of Four Materials in the Orifice of Root Canal Systems Obturated With Gutta-Percha

Failure to maintain the coronal as well as apical seal may expose obturated canals to microbes that could retard healing and create infection in the periodontal ligament or supporting osseous structures. 50 single rooted teeth (Type I canal anatomy) were randomly assigned to 4 experimental and 2 control groups. Ten specimens each were sealed with Mineral Trioxide Aggregate (MTA), Tetric Flow, Glass Ionomer Cement (GIC) and Light Cure Glass Ionomer cement (LC GIC). After creation of uniform orifice diameter, the smear layer was removed and the canal systems obturated using lateral compaction of gutta-percha (GP). GP was removed to the depth of 3.5 mm, experimental materials placed in orifice and the roots submerged in Rhodamine-B dye in vacuum for one week. Specimens were longitudinally sectioned and leakage measured using a 10X stereomicroscope and graded for depth of leakage. According to the result of the present study LC GIC demonstrated significantly better seal (p<.01) than MTA however there was no statistically significant difference in leakage (p>.01) between Tetric Flow, GIC and LC GIC and in between MTA, Tetric Flow and GIC.

Glucose penetration and fluid transport through coronal root structure and filled root canals

To measure glucose penetration and fluid transport through coronal root structure and compare it with leakage along the coronal region of root fillings. A total of 50 single-rooted teeth were selected and divided into three groups. Ten roots were sectioned longitudinally and the apical portion was removed leaving a total length of 9 mm. These 20 half-roots served as group 1: root structure (n = 20). The canals of the remaining 40 roots were prepared to size 50 and filled with vertically compacted injectable filling material and sealer. Group 2: Resilon + Epiphany (n = 20) and group 3: gutta-percha + AH26 (n = 20). The apical portion of the root was removed. Glucose penetration through the coronal root structure and coronal root fillings was checked over a period of 4 weeks and fluid transport was measured after completion of the glucose penetration test. Differences between the groups were statistically analysed with the Kruskal-Wallis test and the Mann-Whitney test. The three groups presented significantly different glucose penetration (P < 0.05). The two groups of filled canals showed significant glucose leakage whilst the root structure group did not show any leakage. In the fluid transport model, the root structure group also did not show any leakage. No significant difference in leakage existed between the two vertically compacted filling materials, Resilon with Epiphany sealer and gutta-percha with AH26 in both models (P > 0.05). Under the conditions of this study, in both models used, no leakage was observed through root structure. Filled canals were associated with penetration of glucose regardless of the material used.

An Evaluation of MTA Cements as Coronal Barrier.

Coronal leakage seems to play an important role in the failure of endodontic treatment. A double seal over root canal filling has been suggested as a means of improving the coronal seal. Several restorative materials have been used in an attempt to produce a coronal barrier. The purpose of this study was to assess gray-coloured mineral trioxide aggregate (GMTA), white-coloured mineral trioxide aggregate MTA (WMTA), and Principle (a resin-modified glass ionomer) as coronal barriers to bacterial leakage. Fifty-one human anterior teeth were cleaned and obturated with gutta-percha and sealer. In group 1, teeth received a 3 mm barrier of GMTA. In groups 2 and 3, samples received WMTA and Principle, respectively. Obturated teeth without barrier were used as positive control and obturated teeth covered with epoxy resin were used as negative control. A leakage model utilizing Enterococcus faecalis used for the evaluation. Leakage was recorded when turbidity was observed. All controls behaved as expected. Three samples in group 1, three samples in group 2, and four samples leaked in group 3. There was no statistically significant difference in leakage between GMTA and WMTA or between GMTA and Principle. It seems that GMTA, WMTA and Principle can be recommended as a coronal barrier for up to 90 days.

Effect of Intracanal Medicament on the Sealing Ability of Root Canals Filled with Resilon

The purpose of this in vitro study was to investigate the effects of the use of calcium hydroxide as an intracanal dressing on the sealing ability of a thermoplastic synthetic polymer-based root filling (Resilon). Forty-seven single rooted teeth were decoronated and instrumented to ISO sizes 40. The teeth were randomly divided into three experimental groups of 15 roots each. Group 1 was immediately filled. Group 2 and group 3 had calcium hydroxide paste placed with lentulo-spiral filler. After 7 days, calcium hydroxide was removed from the canals with two different techniques: #15 K-file agitated irrigation with 17% Ethylenediaminetetracitic acid (EDTA) (group 2) or ultrasonically agitated irrigation with 17% EDTA (group 3) for 2 min. All teeth were filled with Resilon points and the resin sealer (Ephiphany root canal sealant) using lateral condensation technique. Two teeth were immediately filled with Resilon master point size 40/.04 without sealer to act as a positive control. A split chamber microbial leakage model using Streptococcus mutans was used and the leakage was evaluated daily for a period of 30 days. Overall, 6 of 44 (14%) of samples filled with Resilon points and the resin sealer had microbial leakage. Three samples in group 1 (21%), two samples in group 2 (13%), and one specimen in group 3 (7%) had bacterial leakage. Using the Fisher’s Exact test, there was no statistically significant difference in leakage between the groups with calcium hydroxide dressing and the group without calcium hydroxide (p > 0.05). Under the condition of this study, calcium hydroxide did not adversely affect the seal of the root-canal system filled with Resilon.

Furcation Perforation Repair Comparing Gray and White MTA: A Dye Extraction Study

The purpose of this study was to evaluate the ability of gray and white ProRoot MTA to seal furcation perforations in mandibular molars using a dye extraction leakage model. Sixty-four mandibular molars were randomly divided into four experimental groups. Six teeth with perforations were used as positive controls and six teeth without perforations were used as negative controls. Perforations in groups 1 and 2 were repaired with white MTA. Groups 3 and 4 were repaired with gray MTA. Dye leakage was tested from an orthograde direction (groups 1 and 3) and a retrograde direction (groups 2 and 4). After dye extraction, absorbance was measured on a spectrophotometer at 550 nm. No statistically significant difference in leakage was found between gray and white MTA when used as a furcation perforation repair material. However, there was significantly more leakage when the perforations were challenged from the orthograde than the retrograde direction (p < 0.001).

Bacterial Leakage with Mineral Trioxide Aggregate or a Resin-Modified Glass Ionomer Used as a Coronal Barrier

The purpose of this study was to evaluate gray mineral trioxide aggregate (MTA), white MTA, and Fuji II LC cement as coronal barriers to bacterial leakage. Seventy-eight, matched, human teeth were obturated with gutta-percha. In group I, 18 pairs received a 3-mm barrier of gray or white MTA. In group II, 18 pairs received a 3-mm barrier of gray MTA or Fuji cement. Three pairs were used as positive (obturated without barrier) and negative (covered with epoxy resin) controls. A dual-chamber leakage model utilizing salivary microbes was used for the evaluation. Leakage was recorded when turbidity was observed. All controls behaved as expected. In group I, three gray MTA and three white MTA samples leaked. In group II, one gray MTA and three Fuji samples leaked. There was no statistically significant difference in leakage between gray and white MTA or gray MTA and Fuji at 30, 60, or 90 days. Gray and white MTA or Fuji II can be recommended as a coronal barrier for up to 3 months.

Effect of 2% Chlorhexidine Gel as an Intracanal Medication on the Apical Seal of the Root-Canal System

The purpose of this study was to determine what effect intracanal medications might have on the apical seal of the root-canal system. Forty-two teeth were cleaned and shaped in a crown-down manner to a size #50 K-file. The teeth were divided into three groups: (A) immediate obturation; (B) intracanal placement of calcium hydroxide placed for 14 days; and (C) 2% chlorhexidine gel placed for 14 days. After 14 days, these materials were removed using copious irrigation and obturation was completed on groups B and C. Obturation was performed using the continuous wave of condensation technique using AH Plus sealer in all groups. Leakage was evaluated 60 days after obturation by using a fluid-filtration device. Using the one-way ANOVA test, there was no statistically significant difference in leakage between the three groups. Under the conditions of this study, 2% chlorhexidine gel and calcium hydroxide paste did not adversely affect the apical seal of the root-canal system.

A Comparison of Laterally Condensed Gutta-Percha, Thermoplasticized Gutta-Percha, and Mineral Trioxide Aggregate as Root Canal Filling Materials

The purpose of this study was to evaluate the potential of using mineral trioxide aggregate as a root canal filling material by comparing its apical sealing ability with that of laterally condensed gutta-percha with sealer and high-temperature thermoplasticized gutta-percha with sealer in extracted bovine teeth. Sixty bovine incisors with single canals were prepared in a standard manner using LightSpeed instruments, randomly divided into three groups of 20 teeth, and obturated. The sealing ability of each technique was assessed by immersion in 1% methylene blue dye for 3 days. The teeth were cleared, and the linear extent of dye penetration was measured with a stereomicroscope. Data were analyzed by the Kruskal-Wallis one-way ANOVA followed by Dunn's test. Canals filled with laterally condensed gutta-percha or thermoplasticized gutta-percha showed significantly less apical dye penetration than canals obturated with mineral trioxide aggregate (p < 0.001). There was no significant difference in leakage between the laterally condensed group and the thermoplasticized group. The results suggest that gutta-percha obturation may provide an apical seal that is superior to MTA.

An In Vitro Evaluation of the Sealing Ability of a New Root-canal–obturation System

In this study the sealing ability of a new urethane methacrylate resin-based sealer, EndoRez, was evaluated using a fluid-filtration model. Sixty-four single-rooted lower bicuspids were decoronated, instrumented, and divided into 3 groups of 20 each with 4 teeth used as controls. In group A, the roots were obturated with EndoRez and a single cone of gutta-percha, group B with AH Plus and a single cone of gutta-percha, and group C was obturated using gutta-percha with warm vertical compaction and AH Plus sealer. All specimens were allowed to set for 7 days in 100% humidity at 37 degrees C. The groups were compared for differences in the amount of leakage (mm/h) using a Chi-square test. The leakage of group A was significantly higher at p = 0.01 than the other two groups. There was no significant difference in leakage between groups B and C.