Factors influencing the outcome of nonsurgical root canal treatment and retreatment: A retrospective study.

This study assessed the influence of diverse variables on the outcome of nonsurgical root canal treatment/retreatment. In general, 304 teeth from 218 patients were treated/retreated and the outcome evaluated by the periapical index (PAI). Teeth with apical periodontitis lesions that have not completely healed were classified as success or failure based on lenient and rigid criteria, respectively. Findings were evaluated using a logistic regression analysis. The overall success rates were 74% and 82% using the PAI-rigid and lenient success criteria, respectively. Specifically for treatment, the success rates were 73% (rigid) and 82% (lenient), while for retreatment they were 78% (rigid) and 83% (lenient). The treatment outcome was negatively affected by overextension, presence of preoperative lesion, lesion size >10 mm, and higher number of treatment visits (with no intracanal medication). Regarding retreatment, the chance of success was greater for teeth with adequate coronal restorations.

Microbiome-targeted interventions for the control of oral-gut dysbiosis and chronic systemic inflammation.

Recent research has confirmed the strong connection between imbalances in the oral and gut microbiome (oral-gut dysbiosis), periodontitis, and inflammatory conditions such as diabetes, Alzheimer's disease, and cardiovascular diseases. Microbiome modulation is crucial for preventing and treating several autoimmune and inflammatory diseases, including periodontitis. However, the causal relationships between the microbiome and its derived metabolites that mediate periodontitis and chronic inflammation constitute a notable knowledge gap. Here we review the mechanisms involved in the microbiome-host crosstalk, and describe novel precision medicine for the control of systemic inflammation. As microbiome-targeted therapies begin to enter clinical trials, the success of these approaches relies upon understanding these reciprocal microbiome-host interactions, and it may provide new therapeutic avenues to reduce the risk of periodontitis-associated diseases.

Planned Apical Preparation Using Cone-Beam Computed Tomographic Measures: A Micro-Computed Tomographic Proof of Concept in Human Cadavers.

INTRODUCTION: This study assessed the amount of unprepared surface areas at the apical 4-mm segment of the root canal after a planned preparation based on cone-beam computed tomography (CBCT) measurements. METHODS: Eighteen posterior mandible segments were obtained from cadavers and scanned using CBCT and micro-computed tomographic (micro-CT) imaging. CBCT images were used to measure the largest initial canal diameter from 29 root canals of premolars at 1, 2, 3, and 4 mm short of the apical foramen. Each measurement was used to select a master apical instrument with size/taper that was 1 diameter larger to prepare the apical 4 mm of each particular root canal. A post-preparation micro-CT scan was obtained, and the unprepared canal areas were calculated. RESULTS: A very high amount of surface areas over the apical 4 mm of the root canal was included in the final preparation (mean >90%). The unprepared areas ranged from as low as 3.7% to a maximum of 14.6% (mean and median, 9.2% and 9.1%, respectively). CONCLUSIONS: The proposed planned apical root canal preparation resulted in optimized root canal shaping with a substantial amount of prepared surface areas. The protocol used also resulted in a conservative canal enlargement using final instruments that were 1 size larger than the initial largest canal diameter.

Disinfecting and Shaping Type I C-shaped Root Canals: A Correlative Micro-computed Tomographic and Molecular Microbiology Study.

INTRODUCTION: This ex vivo study compared the disinfection and shaping abilities of 2 preparation protocols in C-shaped canals. METHODS: Mandibular second molars with type I C-shaped canals were pair matched based on micro-computed tomographic (micro-CT) analysis and distributed into 2 groups. The canals were contaminated with a mixed bacterial culture and prepared using 2 protocols, both with 2.5% sodium hypochlorite irrigation: XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) supplemented with XP-endo Finisher (FKG Dentaire) (XP-E) and BioRaCe (FKG Dentaire) supplemented with a Hedström file (Dentsply/Sirona, Tulsa, OK) (BR-Hed). Micro-CT scans and intracanal bacteriologic samples were taken before (scan #1 and sample 1) and after preparation (scan #2 and sample 2) and after the supplementary step (scan #3 and sample 3). Canal shaping was evaluated by micro-CT imaging, and disinfection was assessed by quantitative polymerase chain reaction. RESULTS: Micro-CT data from the XP-E (n = 21) and BR-Hed (n = 23) protocols revealed no significant differences between groups regarding shaping parameters (canal volume, surface area, structure model index, and prepared walls) after preparation and after the supplementary step (P > .05). All these parameters significantly increased after each preparation step (P < .05), except for structure model index changes after the XP-endo Finisher (P > .05). Bacteriologic data from the XP-E (n = 21) and BR-Hed (n = 22) groups showed that 14 (66.7%) and 10 (45.5%) S2 samples still had detectable bacteria, respectively. The corresponding figures for supplementary steps with the XP-endo Finisher and Hedström file were 11 (52.4%) and 10 (45.5%), respectively. Bacterial counts in sample 1 significantly decreased in samples 2 and 3 in both groups (P < .01). Intragroup comparison between sample 2 and sample 3 showed a 66% reduction in counts after using the Hedström file and 18% after using the XP-endo Finisher (P > .05 for both groups). The quantitative bacterial reduction was not different between groups (P > .05). CONCLUSIONS: The XP-endo Shaper and BioRaCe systems have similar disinfecting and shaping abilities in C-shaped canals. Supplementary steps with the Hedström file and the XP-endo Finisher were similarly effective in improving shaping, but this was not sufficient to enhance disinfection. About half of the cases, in both groups, still harbored detectable amounts of bacteria.

Outcome of endodontic treatment with chlorhexidine gluconate as main irrigant: A case series.

This study evaluated the overall endodontic therapy success using 0.12% or 2% chlorhexidine gluconate as main irrigant. Seventy-two teeth diagnosed as vital, necrotic or previously treated teeth with apical periodontitis that were consecutively treated by orthograde therapy. All cases were followed clinically and radiographically for at least 1-year period. Success was established in teeth without signs or adverse clinical symptoms and complete or incomplete radiographic healing. Failure was determined in teeth with any sign or adverse clinical symptoms and a new, unchanged or enlarged radiographic periapical lesion. The data were analysed using chi-square and Fischer's exact tests. The overall success rate for teeth undergoing vital pulp was 84.6%, 76.2% as for the necrotic teeth and 84% for the retreatment cases. No significant differences were observed between groups (P > 0.05). Cases treated with CHX as main irrigant showed a high overall endodontic therapy success rate.

Distribution of sodium hypochlorite throughout the mesial root canal system of mandibular molars after adjunctive irrigant activation procedures: a micro-computed tomographic study.

OBJECTIVES: To evaluate and compare irrigant distribution throughout the root canal system of mesial roots of mandibular molars after application of distinct adjunctive irrigant activation procedures. MATERIALS AND METHODS: Fifteen extracted mandibular molars presenting Fan's type II, III, or IV isthmus configurations were selected. The canals were initially enlarged and cleaned. The same specimens were subjected to conventional positive pressure irrigation (PPI) followed by adjunctive irrigation approaches: passive ultrasonic irrigation (PUI), mechanical activation with the XP-endo Finisher instrument, and a control group in which the irrigant remained in the canal with no activation. Retention time for the irrigant was the same for all groups. Sodium hypochlorite mixed with a contrast medium (Omnipaque 300) was used as the irrigant. Before and immediately after the adjunctive irrigation, micro-computed tomographic (micro-CT) scans were taken to evaluate the volume of the entire root canal system that was filled by the irrigant. An exclusive analysis was also done for the isthmus area. RESULTS: Analysis of the entire root canal system showed that the XP-endo Finisher instrument promoted better distribution of the irrigant than PUI and the control group (p < 0.01). PUI was not significantly different from the control group (p > 0.05). A separate analysis of the isthmus area showed no significant difference between the adjunctive irrigation methods and the control (p > 0.05). CONCLUSIONS: The XP-endo Finisher instrument promoted better distribution of irrigant throughout the root canal system, especially in the apical canal segment, when compared to PUI. However, the tested approaches did not differ as to the ability to drive irrigants into the isthmus area. CLINICAL RELEVANCE: This study highlighted that the XP-endo Finisher instrument presented a better performance to distribute irrigant throughout the root canal system, especially in the apical canal segment compared to positive pressure irrigation and PUI.

Transportation assessment in artificial curved canals after instrumentation with Reciproc, Reciproc Blue, and XP-endo Shaper Systems.

AIM: In the present study, we compared the transportation of three different instrumentation systems in different levels of standardized artificial curved canals. METHODS: Sixty epoxy resin blocks containing simulated canals were divided into three groups (n = 20) according to the instrument used for canal preparation: Reciproc (REC), Reciproc Blue (REC Blue), and XP-endo Shaper (XPS). Pre- and post-instrumentation digital images of each specimen were superimposed by Photoshop software to evaluate the different amount of transportation. The Kruskal-Wallis and Wilcoxon were the non-parametric tests applied for the intergroup and intragroup analyses, respectively. The significance level was set at 5%. RESULTS: The XPS showed significantly less canal transportation than REC Blue at five levels (P < 0.05) and significantly less canal transportation at seven evaluated levels when compared with the REC (P < 0.05). REC Blue showed significant less canal transportation than REC at four of the eight evaluated levels (P < 0.05). All evaluated instruments showed a significantly higher amount of resin removal toward the inner wall compared to the outer wall of the curvature (P < 0.001). CONCLUSION: Although the XPS showed significantly less canal transportation than REC and REC Blue, all systems produced transportation from the original canal anatomy.