Effect of synthetic tissue fluid on microleakage of grey and white mineral trioxide aggregate as root-end filling materials

The success of endodontic surgery has been shown to depend partly on the apical seal. Grey mineral trioxide aggregate [GMTA] produces hydroxyapatite twice as often as white mineral trioxide aggregate [WMTA] when suspended in a phosphate buffered saline [PBS] solution. The aim of this in vitro study was to compare the microleakage phenomenon of gray and white mineral trioxide aggregates as root-end filling materials after immersion in synthetic tissue fluid [STF]. 55 single-rooted extracted maxillary anterior human teeth were divided into two experimental groups of 20 teeth each, plus 3 groups of 5 teeth each as two negative and one positive control groups. The root canals were cleaned, shaped, and laterally compacted with gutta-percha. The root ends were resected and 3 mm deep cavities were prepared. The root-end preparations were filled with GMTA or WMTA in the experimental groups. Leakage was determined using a dye penetration method. Data were analysed using analysis of variance [ANOVA] at the 0.05 level of significance. Results: The mean dye leakage was 0.40 +/- 0.1 mm for GMTA and 0.50 +/- 0.1 mm for WMTA groups, respectively. There was no significant difference between the two experimental groups [P = 0.14]. Despite the different properties and behaviours of GMTA and WMTA in STF, there were no significant differences in microleakage when using GMTA or WMTA

Mandibular second premolars with three root canals: a review and 3 case reports

Before initiating any endodontic therapy, probability of extra canals should be considered. The Incidence of three canals in mandibular second premolar has been reported to be 0.46-0.5%. The present report describes nonsurgical endodontic treatment of three mandibular second premolars with three canals. In these cases, three orifices were located in mesiobuccal, distobuccal and lingual. Mesiobuccal orifices were found after removing dentinal shelves. Even in teeth with extremely complex root canal morphologies, conventional endodontic treatment without surgical intervention can result in adequate healing, as in these cases. Clinicians should be aware of unusual root canal anatomy in mandibular premolars. Very careful examination of the pulpal space, preferably with an optical device is recommended to locate any unusual orifices

Endodontic treatment of a hypertaurodont mandibular second molar: a case report

A 28-year old patient was referred for endodontic treatment of his left mandibular second molar. The patient had no history of systemic diseases and his chief complaint was spontaneous pain in left posterior region of mandible. Clinically, there was a deep caries in the left mandibular second molar. Radiographic examination of this tooth revealed a long crown containing large pulp chamber and two short roots with a apically located furcation, indicating hypertaurodontism. After coronal access preparation, five orifices were found including mesiolingual, mesiobuccal, distobuccal, mid-distal and distolingual. Subsequent to root canal preparation, a modified filling technique was used for canal obturation. After one year the treated tooth was symptom free

Comparison between the accuracy of NovApex apex locator and radiographs in determining radiographic apex

Determination of the canal working length with radiographs has many drawbacks. Electronic apex locators have been developed to overcome some of these problems. Recently, a newly designed apex locator called NovApex has been introduced. All the studies conducted to determine the accuracy of NovApex have been carried out in-vitro on extracted teeth. The aim of this in vivo study was to evaluate the accuracy of NovApex compared with traditional radiographic method. Twenty-five patients whose lower molars that were candidates for extraction were selected. The teeth were accessed, and the radiographic working length was determined by measuring the length of the initial file 0.5mm short of the radiographic apex. Then, NovApex apex locator was used to measure the electronic working length. Subsequently, the tooth was extracted, and the actual working length was measured by introducing a size #15 K-file into each canal until the file tip was visible at the apex, then 1.5mm was subtracted to attain the working length. Cohen's Kappa was computed for each of the methods versus actual working length as a measure of reliability. The accuracies were compared using Chi-square test. The accuracy of NovApex apex locator and radiographic method in detecting the apical end point within +/- 0.5mm was 74.7% and 68%, respectively; this was not significantly different [P<0.001]. The NovApex apex locator is useful in detecting the apical end point with the accuracy similar to radiographic method. However, neither technique is fully reliable in detecting the apical end point of the canal

In vitro comparison of dye penetration through four temporary restorative materials

The purpose of this in vitro study was to compare the coronal seal of four temporary filling materials, Coltosol, Zonalin, Zamherir, and Intermediate Restorative Material [IRM] by the India ink dye penetration test. Endodontic access preparations were prepared in 120 extracted intact human premolars. The teeth were randomly divided into six groups including four experimental and two control groups. The access cavities in each group were sealed with Coltosol, Zonalin, Zamherir, and IRM; subsequently thermocycling was applied for 5-55°C for 150 cycles. The teeth were immersed in 10% India ink for 72 hours to assess leakage. The teeth were then rinsed, dried, and sectioned mesiodistally and evaluated under a stereomicroscope for dye penetration. Data were analyzed using one-way ANOVA and post hoc Tukey tests. Positive control specimens showed complete dye penetration, while negative controls had no penetration. In the experimental groups, the lowest and highest leakage scores were observed in the Zonalin and Coltosol groups, respectively [P<0.05]. There were no statistically significant differences in marginal leakage between Zonalin-Zamherir and Coltosol-IRM groups. These results suggest that Zonalin and Zamherir have a superior seal and less micro-leakage into the canals compared to the two other materials

Comparison of apical microleakage using Ni-Ti with stainless steel finger spreaders

The purpose of this in vitro study was to compare apical microleakage after obturation with Nickel-Titanium [NiTi] compared to Stainless Steel [SS] finger spreaders. Eighty straight single-rooted human teeth were instrumented using step-back technique. The specimens were randomly divided into four groups. The two experimental groups [n=30] and the negative control group [n=10] were obturated by lateral condensation technique with Ariadent gutta-percha and AH26 sealer. The roots in the positive control group [n=10] were instrumented but not obturated. In one group, SS and in another group NiTi spreaders were used. Microleakage evaluation was conducted using dye penetration method t-test was used for statistical analysis. The results showed statistically significant differences between NiTi and SS groups [P=0.022], with the greatest dye penetration in SS group and the least in NiTi group. According to the results of the present study using NiTi spreader decrease apical microleakage in endodontically treated teeth

Connective tissue reaction to white and gray MTA mixed with distilled water or chlorhexidine in rats

The purpose of this study was to compare the histocompatibility of white [WMTA] and gray [GMTA] mineral trioxide aggregate mixed with 0.12% chlorhexidine [CHX] and distilled water [DW] in subcutaneous connective tissues of rats. The freshly mixed WMTA and GMTA with CHX or DW were inserted in polyethylene tubes and implanted into dorsal subcutaneous connective tissue of 50 Wistar Albino rats; tissue biopsies were collected and were then examined histologically 7, 15, 30, 60 and 90 days after the implantation procedure. The histology results were scored from 1-4; score 4 was considered as the worst finding. Data were analyzed using one-way ANOVA tests. All experimented materials were tolerated well by the connective tissues after 90- day evaluation, except for the WMTA/CHX group that had significantly more mean inflammatory scores [P<0.001]. There was a statistically significant difference in the mean inflammation grades between experimental groups in each interval [P<0.001]. After 90 days, GMTA/CHX group had the lowest inflammatory score. Although adding CHX to WMTA produces significantly higher inflammatory response, it seems a suitable substitute for DW in combination with GMTA. Further research is necessary to recommend this mixture for clinical use

Root canal morphology of human mandibular first permanent molars in an Iranian population

The knowledge of variations in root canal morphology is critical for a successful endodontic treatment. The purpose of this study was to investigate variations in the root canal system of human mandibular first permanent molars in an Iranian population. In this study, 209 mandibular first molar teeth were decalcified, dye-injected, and cleared in order to determine the number and configuration of the root canals. The results demonstrated that 65.56% of the mandibular first molars under study had three, 31.57% had four and 2.87% had two canals. According to the results of this study and considering variations in the root canal systems of the mandibular first molars, it seems that great care should be taken in the root canal treatment of these teeth

comparative scanning electron microscope investigation of cleanliness of root canals using hand K-Flexofiles, rotary RaCe and K3 instruments

The most important aims of root canal preparation are the removal of vital pulp tissue, remaining necrotic debris and infected dentin, eliminating the bulk of bacteria present in the root canal system. The aim of this study was to compare the cleaning efficacy of hand K-Flexofiles and rotary RaCe and K3 instruments in root canal preparation. A total of 60 single rooted teeth with maximum curvature of <20§ were selected and divided into three groups of 20 teeth each. Canals were prepared with KFlexofiles, K3 and RaCe instruments using crown down preparation technique, up to size #30. After instrumentation, the root canals were flushed with 5 mL of 2.5% NaOCl solution. The amount of debris and smear layer was quantified on the basis of Hulsmann method using a scanning electron microscope. The data were statistically analyzed with one-way ANOVA test at a significance level of P<0.05. None of the three groups achieved completely debrided root canals.. In general, KFlexofiles were able to achieve cleaner canals compared to K3 and RaCe instruments [P<0.05]. There were no significant differences between three groups in smear layer removal throughout the root canal walls [P<0.05]. K-Flexofiles group had less remained debris when compared to K3 and RaCe instruments

Root canal configuration of maxillary first permanent molars in an Iranian population

It is critical to have a proper knowledge of the normal anatomy of the pulp and its variations for the success of endodontic treatment. The purpose of this study was to investigate variations in the root canal system of maxillary first permanent molars in an Iranian population. In this study, 137 maxillary first molars were decalcified, dye-injected, cleared and studied. The results demonstrated that 37.96% of the maxillary first molars under study had three canals, 58.4% had four canals and 3.64% had five canals. According to the results of this study and considering variations in the root canal systems of maxillary first molars, it seems that great care should be taken in the root canal treatment of these teeth

Root canal configuration of mandibular first and second premolars in an Iranian population

It is critical to have a proper knowledge of the normal anatomy of the pulp and its variations for the success of endodontic treatment. The aim of this study was to determine the canal configuration and the prevalence of C-shaped canals in mandibular first and second premolars in a North-Western Iranian population. A total of 163 extracted mandibular first and 103 mandibular second premolars were injected with India ink and demineralized. They were made clear and transparent with methyl salicylate and the anatomy of their canal[s] was studied. The results showed that 98% of mandibular first premolars had one root, 2% had two roots, 70.6% had one canal, 27.8% had two canals, 1.2% had three canals and the prevalence of C-shaped canals was 2.4%. All mandibular second premolars had one root, 80.5% had one canal, 17.5% had two canals and the prevalence of C-shaped canals was 2%. It is important that clinicians, before treatment of mandibular first and second premolars, pay complete attention to radiographs, have a true concept of the number of root[s] and canal[s], and prepare a correct access cavitiy