effect of one-step or two-step MTA plug and tooth apical width on coronal leakage in open apex teeth

Mineral trioxide aggregate [MTA] has been suggested as an effective material for apical barrier, forming an effective seal against bacterial leakage in teeth with open apices. MTA needs moisture for setting; which can come from the apical region or a moist cotton pellet. This study was intended to compare bacterial leakage in one- and two-step MTA apical barrier technique in open apices with different diameters. The root canals of 52 extracted human maxillary incisors were prepared and open apices in two different diameters of 1 and 1.4 mm were created. The samples put in experimental groups randomly. A 4-mm thickness of MTA was placed as apical barrier for both one- and two-step methods. In one-step groups [1.4 mm diameter; n=12 and 1 mm diameter; n=12], the samples were obturated immediately after placing MTA plug. For two-step groups [1.4 mm diameter; n=12 and 1 mm diameter; n=12], a moist cotton pellet was placed over the MTA plug for 3 days before root canal obturation. Four samples served as positive/negative control groups. After one week, microleakage was evaluated using bacterial penetration technique and results were statistically analyzed utilizing SPSS software and Chi-square test. In one-step technique 13 and in two-step technique 12 samples showed bacterial leakage. There was no statistically significant differences between two techniques [Chi square, P=1]. The difference between the results related to 1 and 1.4 mm apical foramens was also not significant [P=1]. Also 12 and 13 samples showed bacterial contamination in teeth with 1 mm and 1.4 mm apical foramens, respectively [P=1]. It seems that leakage of MTA apical plug using one- and two-step technique is comparable; however, in vivo investigations are highly recommended for more accurate results

Hydroxyl ion diffusion through intact and resorbed roots at various time intervals

The purpose of this study was to investigate root surface pH changes over a period of 4 weeks following treatment with calcium-hydroxide dressing of intact and resorbed roots. The canals of 30 single-rooted teeth were instrumented with ProTaper rotary files and randomly divided into 2 experimental groups of 14 each, and one control group with two samples. To simulate external resorption in group 2 and control, two defects were made on the buccal and lingual mid-root surfaces of each tooth with a diamond bur [1x1mm]. Teeth were then submerged in 20% sulfuric acid for 4 days. Canals of 14 intact teeth in group 1, and 14 resorbed teeth in group 2 were filled with calcium hydroxide Ca[OH]2 while canals of resorbed teeth in control group were filled with saline. All teeth were then placed in a glass vial containing 15mL of deionized water [pH?7]. The pH of water was measured at 0 and 1, 4, 7, 10, 14, 21 and 28 days using pH microelectrode. Independent t-test and repeated measured ANOVA analyzed the data. Except a mild decline at 7days and 14days, the average pH values showed increased during the time periods of this study. Day 28 showed the maximum pH average value in both groups [7.67-7.72] [P<0.05]. Significant increase of pH values were detected at different time intervals compared with the baseline time [P<0.05]. Diffusion of hydroxyl ions was similar in both resorbed and intact roots. In both groups pH values were significantly higher than the baseline pH at the various times

effect of blood on apical microleakage of Epiphany and AH26: an in vitro study

Blood contamination of the canal during preparation can be a major problem in endodontics; this may result in apical microleakage. The aim of this in vitro study was to evaluate the effect of blood on apical microleakage of a resin-based root canal sealer [AH26] and a polymer-based root canal sealer [Epiphany].In this experimental study, 50 decoronated' central incisors and canine teeth were prepared by RaCe rotary system and randomly divided into 4 groups [n=10]. Groups A[1] and A[2] were obturated by Epiphany/Resilon and AH26/Gutta-percha, respectively. The obturations were performed with a single cone technique after drying root canals. In B[1] and B[2] groups, the test groups, 0.02cc citrated human blood was injected into dried root canals and they were obturated in the same manner. Ten specimens were served as positive and negative controls [n=5].The apical leakage was measured by means of a computerized fluid filtration method after 1 day and 3 weeks. The data was analyzed by One-Sample Kolmogorov-Smirnov, Independent Sample t-test and univariate analysis. Statistical significances were preset at a=0.05. There was no significant difference in apical microleakage of the two sealers after 1 day and 3 weeks in dry and blood environment [P>0.05]. Sealer and environment had no interaction [P>0.05]. Blood contamination has no significant effect on the apical microleakage of Epiphny and AH26

Efficacy of two rotary systems in removing gutta-percha and sealer from the root canal walls

The aim of this in vitro study was to compare the efficacy of two retreatment rotary systems in removal of gutta-percha [GP] and sealer from the root canal walls with and without use of solvent. Sixty single-canalled distal roots of mandibular molars were prepared and root filled with gutta-percha and AH26. Each canal was randomly allocated to receive one of the retreatment techniques, Mtwo R or ProTaper. The groups were further divided into two subgroups: with or without the use of solvent. The cleanliness of canal walls was determined by stereomicroscope and scanning electron microscopy. The results showed that Mtwo R without the use of solvent was more efficient in material removal compared to ProTaper D [P<0.05]. Most remnants were found in the apical third of the canals [P<0.05]. Mtwo R seems to be an efficient rotary system for endodontic retreatment of root canal with GP

comparative study on anti-hyperalgesia effect of MTA and ketoprofen in inflammatory pain

Mineral trioxide aggregate [MTA] is an endodontic material with different clinical applications e.g. root-end filling, pulp capping and perforation repair. It has been reported to possess antimicrobial and antifungal activities. The aim of this study was to examine the effect of White MTA on formalin-induced hyperalgesia in a rat with inflammatory pain. Inflammatory pain was induced by subcutaneous [SC] injection of formalin [40 microL, 2.5%] into the rat upper lip. The nociceptive behavioral responses i.e. shaking of the lower jaw and face rubbing were quantified. 40 uL of eugenol [50 mg/kg], WMTA [20 mg/0.2 mL] or ketoprofen were injected solely or in combination with formalin 2.5% and the behavioral responses were compared with those observed after formalin treatment alone. One-way ANOVA, Tukey were used for analysis of data. Formalin 2.5% provoked a biphasic nociceptive response, with an early and short lasting first tonic phase followed by a second phase. Solely SC injection of either WMTA or ketoprofen [a non steroidal anti-inflammatory drug] did not stimulate any significant nociceptive behaviour. However, injection of eugenol [a pain relieving agent] induced the early phase not the tonic phase of nociceptive response. WMTA, eugenol or ketoprofen injection 20 min before formalin injection attenuated the first phase but somehow prevented the induction of the second phase of nociceptive responses which were produced by formalin. Behavioural nociceptive responses including shaking of the lower jaw and face rubbing were significantly reduced when the subject was pretreated with either WMTA or ketoprofen [P<0.001]. In this study, WMTA induced pain reduction by suppression of the formalin-induced nociceptive response

new approach to root formation

In endodontics, treatment of an open apex tooth with necrotic pulp is a problem. It seems that with promotion of remnants of Hertwig's epithelial sheath or rest of malassez accompany with a good irrigation of root canal we can expect root formation

Comparison of pulpotomy with formocresol and MTA in primary molars: a systematic review and metaanalysis

There are various studies looking at the effects of formocresol [FC] and mineral trioxide aggregate [MTA] on pulpotomy of primary molars. This is a systematic review of literature comparing the success rates of MTA and FC in pulpotomy of primary molars. The study list was obtained using PubMed, EMBASE, Scopus, Science Citation Index, Iran Medex, Google Scholar, the Cochrane Library, and also some hand searches contains through dental journals approved by the Iranian Ministry of Health. Papers which met the inclusion were accepted. The quality of studies for the meta-analysis was assessed by a series of validity criteria according to Jadad's scale. Eight qualified studies met the criteria. Terms of clinical outcomes and radiographic findings were evaluated in all studies to assess clinical success and root resorption. Fixed model was applied to aggregate the data of homogenous studies. A random effect model was carried out for measuring the effect size of heterogeneous studies. The overall clinical and radiographic success rates based on the data suggested that MTA was superior to FC [P=0.004] with the Odds Ratio=3.535 and 95% confidence interval [1.494-8.369]. Primary molars pulpotomy with MTA have better clinical and radiographic success rates than FC

Technical quality of root canal treatment performed by undergraduate dental students

This study was carried out to evaluate the technical quality of root canal treatment [RCT] performed by undergraduate dental students at the Islamic Azad University in Tehran, Iran. Four-hundred records of patients who had received RCT at faculty of dentistry, between the years 2004-2006 were evaluated. For each treated tooth at least three periapical x-rays were assessed: preoperative, working length measurement, and postoperative. Evaluation of root canal filling was based on two variables: length and density. The filling length was recorded as adequate, under- or overfilled. Density of filling was recorded as poor or adequate. Fillings with adequate length and density were recorded as acceptable. Detected iatrogenic errors were: ledge formations, root perforations, furcation perforations, strip perforations and presence of fractured instruments. Results were evaluated statistically using one-way ANOVA and Chi-square analysis. Out of the 400 teeth, 50.5% had at least one of the mentioned errors. Acceptable filling was observed in 32.5% of all studied teeth. Ledge was found in 17.5% of the teeth. Canal curvature was the most important factor associated with ledge formation [P<0.05]. The technical quality of RCT performed by undergraduate dental students using step-back preparation and cold lateral condensation was classified as acceptable in 32.5% of the cases

External root resorption: Arrested or progressing?

External root resorptionmay be an uncontrolled phenomenon, and themost known interventions have no effect. Even progressive external root resorption may not be controlled by long term Ca[OH][2] therapy. Currently, there are no treatment options for vital tooth that suffer from root resorption. This invasive resorption can lead to extraction of the tooth. The use of new technologies such as low power laser may control this type of resorption