A comparative SEM investigation of the smear layer following preparation of root canals using nickel titanium rotary and hand instruments.

The aim of this study was to compare the efficacy of NiTi flex K-file instruments and rotary FlexMaster and Race instruments (short for reamers with Alternating Cutting Edges) in root canal preparation. A total of 75 single rooted teeth with minimum curvature (< 5 degrees ) were selected and divided into three groups, each containing 25 teeth. Canals were prepared with NiTi flex K-file, FlexMaster and Race instruments using crown down preparation technique, up to size #40. After each instrument, the root canals were flushed with 5 ml of 0.5% NaOCl solution. The amount of debris and smear layer was quantified on the basis of Hulsmann method using a scanning electron microscope. Completely cleaned root canals were not found after instrumentation with any of the three instruments. In general, FlexMaster instruments left significantly less debris and smear layer than Race and NiTi flex K-file instruments (P < 0.05). NiTi flex K-files resulted in significantly more smear layer (P < 0.05) compared to Race and FlexMaster instruments only in the apical third of the canal.

An evaluation of microbial leakage after using MTAD as a final irrigation.

Cleaning the root canal is not possible without using proper irrigation. The aim of this in vitro study was to evaluate the effect of MTAD as a final irrigant on bacterial leakage of the root canal, and its interaction with two conventional root canal sealers. We used 132 extracted human maxillary anterior teeth. The teeth were randomly divided into three experimental groups (n=40) and two groups (n=6) of positive and negative control. In group 1, the smear layer was not removed and irrigation was performed using 5.25% NaOCl. In group 2, the smear layer was removed using EDTA, and in group 3, the smear layer was removed using MTAD according to the clinical protocol of use. The teeth in each group were obturated with gutta-percha and AH-Plus or Rickert sealer. The coronal portion of each root was placed in contact with inoculum of Streptococcus mutans in Brain Heart Infusion (BHI) culture media. Each root tip was placed in one bottle containing sterile BHI. Mean duration of bacterial penetration in groups 2 and 3 was significantly greater than in group 1, but there was no significant difference between groups 2 and 3. According to our findings, it takes longer for bacteria to penetrate when either EDTA or MTAD is used for smear layer removal. The root canals obturated with AH Plus showed significantly longer duration of resistance to bacterial penetration than canals obturated with Rickert.

Endodontic treatment with MTA apical plugs: a case report.

Apexification with calcium hydroxide is associated with certain difficulties, such as the very long treatment time required, the possibility of tooth fracture, and incomplete calcification of the bridge. Use of an apical plug is an alternative treatment for open apices, and this has gained popularity in recent years, employing mineral trioxide aggregate (MTA) for optimal results. Here we report the successful treatment of two maxillary central incisors that had open apices and periapical lesions using MTA apical plugs after the root canals had been debrided and rinsed with 2.5% NaOCl. Calcium hydroxide paste was then placed in the canals for 1 week, before the apical portion of the canals (5 mm) was filled with the MTA plug. The remaining portion of the root canal was then sealed with a post and crown. After 6 months of follow-up, the clinical and radiographic appearance of the teeth showed a decrease of the periapical lesions. At 2 years, although the left post had been lost and the periapical lesion of the left central incisor had subsequently deteriorated, the right central incisor had healed successfully. Considering the importance of a coronal seal, the use of MTA for apical plugging appears to be a valid option.

Clinical and Radiographic Evaluation of Success Rate with MTA Plug in Open Apices.

INTRODUCTION: The ideal endodontic treatment for the teeth with in complete root-ends and necrotic pulps may involve the use of material which forms an immediate apical barrier instead of long term calcium hydroxide therapy. Such procedure may lead us to a single appointment endodontic treatment. The purpose of the present study was to evaluate clinical and radiographic success rate in necrotic teeth with open apices treated with MTA as an apical plug. MATERIALS AND METHODS: Thirty five patients between the ages of 8-16 with total number of 41 necrotic anterior teeth containing open apices were selected. In the first visit, root canals were debrided and filled with calcium hydroxide. After one week, calcium hydroxide was removed and MTA with the thickness of 3 to 4 mm was put in the apical region of the canals. After 24 hours, the remaining part of the canals was filled with guttapercha and sealer and the teeth were restored with composite. All the cases were evaluated clinically and radiographically after 3 and 6 months and data were analyzed by McNemar test. RESULTS: No clinical symptoms were observed in 97.6% of the teeth after 3 months and in none after 6 months. The study showed a significant difference from pretreatment status. After 3 months radiographic evaluation showed that in 17 cases (41.5%), lesions were reduced and in 14 cases (34.1 %), lesions remained the same, and in 10 cases (24.4%) lesions disappeared. After 6 months in 21 cases (51.2%), lesions were reduced, in 3 cases (7.3%) lesions remained the same and in 17 cases (41.5%) lesions disappeared. These finding were statistically different from pretreatment data. CONCLUSION: The results indicate that MTA can be used as an apical plug in the teeth with open apices following root canal debridement and disinfection with calcium hydroxide. Further investigations with longer follow-ups are recommended in order to evaluate the effect of this material.

Evaluation of apically extruded debris in conventional and rotary instrumentation techniques.

OBJECTIVE: The purpose of this in vitro study was to compare two common techniques, conventional and rotary instrumentation, in debris extrusion. METHODS AND MATERIALS: Two hundred mature human teeth with mature apices and less than 15 degrees of root curvature as determined by Schneider's method were selected for use. Teeth were randomly divided into four groups of 50 teeth each and prepared using step-back instrumentation and profile 4 percent Taper Series 29 rotary system at three different speeds: 1,000 rpm, 8,000 rpm and 24,000 rpm. All of the speeds were reduced by contra angle to 1/6 rpm. Extruded debris were collected on pre-weighed vials containing distilled water through the apical foramen during instrumentation. The vials were then dried in a microwave oven at 150 degrees Celsius and weighed again. The difference was recorded as "the weight of the extruded debris." Eight control vials, two for each group, were weighed and filled with distilled water, dried, and reweighed. The mean weight of extruded debris for each group was statistically analyzed. T-student, unilateral variance analysis and Pearson tests were used in this study. RESULTS: Step-back instrumentation (Group 1) produced significantly more debris than other groups. The difference in the amount of debris produced among rotary groups was not significant. CONCLUSION: Rotary technique could reduce the amount of debris extrusion.