METHODS: Studies were identified from 4 electronic databases up to June 2019. Randomized clinical trials (RCTs) comparing the anesthetic success rate of GG, VA, and MI NBs with IANBs in mandibular premolars and molars with irreversible pulpitis were included. The quality of selected RCTs was appraised using the revised Cochrane risk of bias tool. Random-effects meta-analyses of risk ratio (RR) and 95% confidence intervals (CIs) were calculated, and random errors were evaluated by TSA. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation approach.
RESULTS: Five RCTs were included; 2 of them were classified as low risk of bias. No significant difference was observed in the anesthesia success rate compared between GG and IA NBs (RR = 1.10; 95% CI, 0.82-1.48; I2 = 0%). Similarly, no difference was evident between MINB and IANB (RR = 1.15; 95% CI, 0.97-1.36; I2 = 0%). Overall, the cumulative success rates for the 3 anesthetic techniques were low. TSA showed a lack of firm evidence for the results of the meta-analysis between GG NB and IANB. The Grading of Recommendations, Assessment, Development and Evaluation approach evaluation showed that the evidence was of moderate quality for GG NB and IANB compared with low quality for MI and IA NBs. Because only 1 study was available comparing VA NB and IANB, a meta-analysis was not performed. The adverse effect associated with MI NB was swelling, whereas it was prolonged numbness for IANB.
CONCLUSIONS: GG NB and IANB showed similar anesthetic efficacy compared with IANB in mandibular teeth with irreversible pulpitis. However, the success rates for each technique indicate the need for supplemental anesthesia. Further well-designed RCTs evaluating different anesthetic techniques with and without supplemental injection are required to provide stronger evidence.
METHODS: This systematic review was undertaken following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The protocol has been registered with the International Prospective Register of Systematic Reviews (number CRD42019127021). A comprehensive literature search was performed by 2 independent reviewers using a selected search strategy in 2 electronic databases (PubMed and Scopus) until January 28, 2019. A further search was performed manually in endodontic journals. Studies investigating or comparing at least 1 shaping property resulting from root canal instrumentation with a glide path or preflaring in human extracted teeth or clinical studies were included.
RESULTS: The literature shows that the definition of glide path and preflaring procedures remains controversial, which requires an elaboration in the American Association of Endodontists' Glossary of Endodontic Terms. After the removal of irrelevant and duplicated articles, 98 articles were included. The impact of glide path preparation and preflaring on working length determination, apical file size determination, canal transportation, separation of endodontic files, shaping time, dentinal microcrack formation, and extrusion of debris was discussed. Because of heterogeneity among the included studies, quantitative synthesis was not performed for most of the parameters.
CONCLUSIONS: An evidence-based guideline is needed to define and correlate the basic concepts and current applications of each step of contemporary advancements in root canal instruments. Glide path preparation reduces the risk of debris extrusion, has no influence on the incidence of dentinal crack formation, and improves the preservation of the original canal anatomy. The creation of a glide path may have no impact on Reciproc files (VDW, Munich, Germany) in reaching the full working length. Preflaring increases the accuracy of working length determination. Further randomized clinical trials are required to evaluate the effect of a glide path and preflaring on root canal treatment outcomes.
DESIGN: Intracanal samples were collected from primarily infected (n = 10) and post-treatment infected (n = 10) root canals of human teeth using sterile paper points. Bacterial DNA was amplified from seven hypervariable regions (V2-V4 and V6-V9) of the 16S rRNA gene, then sequenced using next-generation sequencing technology. The data was analyzed using appropriate bioinformatic tools.
RESULTS: Analyses of all the samples revealed eight major bacterial phyla, 112 genera and 260 species. Firmicutes was the most representative phylum in both groups and was significantly more abundant in the post-treatment (54.4%) than in primary (32.2%) infections (p>0.05). A total of 260 operational taxonomic units (OTUs) were identified, of which 126 (48.5%) were shared between the groups, while 83 (31.9%) and 51 (19.6%) disparate species were isolated from primary and post-treatment infections, respectively. A significant difference in beta, but not alpha diversity was noted using several different indices (p< 0.05). Differential abundance analysis indicated that, Prevotella maculosa, Streptococcus constellatus, Novosphigobium sediminicola and Anaerococcus octavius were more abundant in primary infections while Enterrococcus faecalis, Bifidobacterium dentium, Olsenella profusa and Actinomyces dentalis were more abundant in post-treatment infections (p <0.05).
CONCLUSION: Significant differences in the microbiome composition and diversity in primary and post-treatment endodontic infections were noted in our UAE cohort. Such compositional differences of microbiota at various stages of infection could be due to both intrinsic and extrinsic factors impacting the root canal ecosystem during disease progression, as well as during their therapeutic management. Identification of the key microbiota in primarily and secondarily infected root canals can guide in the management of these infections.