METHODS: A literature search was performed in 3 electronic databases for articles published before August 2018. Randomized clinical trials published in English that compared PP between machine-assisted agitation and syringe irrigation with needles as part of nonsurgical root canal treatment were included. Two authors were independently involved in the article selection process, data extraction, and assessment of the quality of included studies using the revised Cochrane risk of bias tool. The pooled effect estimates of the standardized mean difference (SMD) between machine-assisted agitation and syringe irrigation with needle was calculated by a random effects-modeled meta-analysis. A subgroup meta-analysis was performed. The quality of evidence was evaluated by the Grading of Recommendations, Assessment, Development and Evaluations approach.

RESULTS: Six studies were included for systematic review. Meta-analysis was performed using 3 studies and showed that machine-assisted agitation resulted in less PP compared with syringe irrigation with needle at 24 hours (SMD = -0.73; 95% confidence interval, -1.04 to -0.42; I2 = 30.6%) and 48 hours (SMD = -0.60; 95% CI, -0.85 to -0.35; I2 = 0%). The quality of evidence by Grading of Recommendations, Assessment, Development and Evaluations for the PP outcomes (24 hours and 48 hours) was graded as "moderate" quality.

METHODOLOGY: STROBE guidelines were used to design a study using 60 periodontal ligament samples obtained from healthy lower premolars where extraction was indicated for orthodontic reasons. Prior to extraction 40 of these premolars were equally divided into four groups and root canals were prepared using different systems: Mtwo, Reciproc Blue, HyFlex EDM and Plex-V. Ten premolars were prepared with hand files and served as a positive control group. The remaining 10 premolars where extracted without treatment and served as a negative control group. All periodontal ligament samples were processed to measure the expression of SP, CGRP and their receptors by radioimmunoassay. Kruskal-Wallis and Duncan tests were performed to determine statistically significant differences between the groups for each variable.

MATERIALS AND METHODS: Ninety human single rooted maxillary and mandibular teeth were selected for this study. The teeth were randomly divided into two experimental groups and one control group as follows: Group A (Ethanolic extract of Sapindus Mukorossi), Group B (17% EDTA), and Group C (Distilled water). The root canals of all three groups were prepared with stainless steel K-files by means of the standard step-back technique and irrigated with 5.25% sodium hypo chloride. The teeth were decoronated, following the irrigation and divided longitudinally into two-halves and visualized using scanning electron microscope (SEM) for the amount of smear layer present utilizing the three-point score system. The observations were noted both before and after the treatment. Nonparametric tests were applied for the comparison and p-value ⩽ 0.05 was considered as statistically significant.

RESULTS: It was evident from that smear layer was completely removed in coronal portion of 27 out of 30 teeth in-group A. For middle and apical areas of group A, 24 and 19 teeth showed complete smear layer removal. In-group B it was found that there were 24, 21, and 3 teeth at coronal, middle and apical, areas respectively where smear layer were completely absent. Intra group comparison showed a significant difference (p = 0.002) in smear layer removal was found for group A at coronal, middle and apical thirds. Similarly, a significant difference (p = 0.001) was also found for group B; however heavy smear layer was found among the three parts of the canal for group C.

MATERIALS AND METHODS: A systematic review of studies comparing the fracture resistance and/or endodontic outcomes between different AC designs was conducted in two electronic search databases (PubMed and Web of Science) following the PRISMA guidelines. Study selection, data extraction, and quality assessment were performed. Meta-analyses were undertaken for fracture resistance and root canal detection, with the level of significance set at 0.05 (P = 0.05).

Settings and Design: Endodontic treatment aims at disinfection and then obturation of root canal system in to prevent re-infection. Root canal irrigants play a pivotal role in the disinfection process. One of the important properties of an irrigant is the removal of complete smear layer and debris. Smear layer has the potential to protect bacteria within the dentinal tubules; therefore removal may be prudent. Smear layer removal increases the bond strength of resin sealers which results in better apical seal.

Materials and Methods: Forty extracted single-rooted, primary teeth were allocated randomly into four groups of ten each: Group 1 - NaOCl, Group 2 - Nutmeg, Group 3 - Myrobolan, and Group 4 - Tulsi. Samples were stored in sterile saline (0.9% NaCl) and then decoronated at the level of the cementoenamel junction. Working length was determined followed by appropriate irrigation. The roots were split into two halves with a chisel and were stored in 2.5% glutaraldehyde solution for 24 h. After fixation, the samples were dehydrated in ethanol series (70, 90, and 95 and twice at 100%). Each specimen was mounted on Al stub and sputter coated with a 20 nm layer of gold. Samples were then examined using a SEM quantum 60 at magnification of ×2000.

Results: Tulsi demonstrated the most statistically significant results followed by myrobolan and nutmeg extract. All herbal extracts were found to be significantly effective than 2.5% NaOCl.