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Subgingival dental restorations and periodontal health have been studied for many years; however, there is a low histological evidence on the behavior of new materials in the supracrestal tissue attachment. The aim of this study is to analyze the periodontal response when a tricalcium silicate material (TSM) or composite margin restorations is placed to 0.5 mm and 1.5 mm from the bone crest with a histomorphometric analysis in dogs. Nine mongrel dogs were used in this study: four dogs (8 canine teeth) for TSM group, 4 dogs (8 canine teeth) for composite group, and 1 dog (2 canine teeth) with cavities without restorations. Cavity preparation of 2×2×1 mm was created on the buccal aspect of the canines at 0.5 and 1.5 mm of the crestal bone. Cavities were restored with composite and TSM or were left unrestored as control. After 12 weeks of healing, the dogs were euthanized and blocks containing the tooth and soft tissues were processed. In all the specimens, the junction epithelium was stablished apical to the tooth preparations. A shorter distance to the bone (0.5 cavity) implies greater apical periodontal migration regardless of the material used. In the TSM groups, the connective tissue height and the distance between bone level and apical margin preparation were greater than those in the composite groups, while the epithelium height was less. However, there were no statistically significant differences comparing TSM and composite groups at either 0.5 mm or 1.5 mm (p > 0.05). Histologic analysis did not show periodontal reattachment to TSM or composite. In both cases, bone crest migrates apically. For that reason, it is recommended to perform composite restorations at the subgingival level whenever the distance to the bone crest is at least 2 mm. Both composite and TSM do not achieve reinsertion of the connective tissue in the biological width.

The aim of this study was to evaluate the effectiveness of smear layer removal after the use of different irrigation methods (passive ultrasonic irrigation (PUI), continuous ultrasonic irrigation (CUI), apical negative pressure irrigation and conventional irrigation) using scanning electron microscopy (SEM) as an analytical tool. A total of 100 single-canal teeth were decoronated and randomly divided into five groups (n = 20) according to the irrigation method used: conventional irrigation with front outlet syringe, conventional irrigation with lateral outlet syringe, apical negative pressure irrigation (EndoVac), PUI with Irrisafe and CUI with ProUltra PiezoFlow ultrasonic irrigation needle. Root canal preparation was performed with the ProTaper Gold system up to the F4 instrument, and 5.25% NaOCl was used as an irrigant. After chemical-mechanical preparation, the roots were split longitudinally, and the coronal, middle and apical thirds were examined. SEM digital photomicrographs were taken at ×1000 magnification to evaluate the amount of smear layer in each root canal third; CUI significantly removed more smear layer than any other irrigant activation protocol (p < 0.05); CUI was more effective in removing the smear layer than the other irrigation protocols. However, none of the irrigation protocols were able to produce root canals completely free from smear layer.

The aim of this study was to evaluate the effectiveness of smear layer removal after the use of different irrigation methods (passive ultrasonic irrigation [PUI], continuous ultrasonic irrigation [CUI], apical negative pressure irrigation and conventional irrigation) using the scanning electron microscopy (SEM) as an analytical tool. A total of 100 single-canal teeth were decoronated and randomly divided into five groups (n = 20) according to the irrigation method used: conventional irrigation with front outlet syringe, conventional irrigation with lateral outlet syringe, apical negative pressure irrigation (EndoVac), PUI with Irrisafe, and CUI with ProUltra PiezoFlow ultrasonic irrigation needle. Root canal preparation was performed with the ProTaper Gold system up to the F4 instrument and 5.25% NaOCl was used as an irrigant. After chemical-mechanical preparation, the roots were split longitudinally, and the coronal, middle and apical thirds examined. SEM digital photomicrographs were taken at ×1000 magnification to evaluate the amount of smear layer in each root canal third. CUI was more effective in removing the smear layer than the other irrigation protocols. However, none of the irrigation protocols were able to produce root canals completely free from smear layer.

The aim of this study was to evaluate the efficacy of continuous apical negative ultrasonic irrigation into simulated lateral canals and the apical third in straight and curved root canals. Two simulated lateral canals were created 2, 4 and 6 mm from the working length in 120 single-rooted teeth (6 canals/tooth, n = 360 straight, n = 360 curved). The teeth were randomly divided into 3 experimental groups: positive pressure irrigation (PPI) (n = 20); passive ultrasonic irrigation (PUI) (n = 20); continuous apical negative ultrasonic irrigation (CANUI) (n = 20). 20% Chinese ink was added to a 5% sodium hypochlorite solution and delivered into the root canals. The results showed a significantly higher (P

Introduction The aim of this study was to evaluate the influence of rotary (ProTaper Next [PTN; Dentsply Maillefer, Ballaigues, Switzerland] and ProTaper Gold [PTG, Dentsply Maillefer]) and reciprocating (WaveOne Gold [WOG, Dentsply Maillefer]) systems in dentinal microcrack generation after the preparation of curved root canals using micro–computed tomographic analysis. Methods Twenty-four human mandibular molars with curved roots were scanned in a micro–computed tomographic device using an isotropic resolution of 6.78 μm and randomly assigned into 1 of 3 experimental groups (n = 8) according to the root canal instrumentation system used (PTN, PTG, or WOG). Then, the root canals were prepared up to PTN X2, PTG F2, and WOG Primary instruments in the PTN, PTG, and WOG groups, respectively. After canal preparation, each specimen was scanned again. Pre- and postoperative cross-sectional images of the roots (N = 35,304) were analyzed to identify the presence of dentinal microcracks. Results Overall, 26% of the images presented dentinal defects (n = 9188). Dentinal microcracks were observed in 24.6%, 26%, and 27.4% of the postinstrumentation images from the PTN, PTG, and WOG groups, respectively. However, all of these dentinal microcracks were already present in the corresponding preoperative images. No new microcracks were generated after the preparation of curved root canals of mandibular molars using the aforementioned systems. Conclusions Root canal instrumentation with PTN, PTG, and WOG systems did not induce the formation of new dentinal microcracks. Sin financiación 4.4422 JCR (2021) Q1, 13/92 Dentistry, Oral Surgery & Medicine 1.599 SJR (2021) Q1, 4/142 Dentistry (miscellaneous) No data IDR 2021 UEM

Background: In this study, the authors assessed the readability of online endodontic information in English and Spanish. Methods: The authors performed a systematic search in Google in May 2016. Search queries were “root canal treatment” and “?Que es una endodoncia?” without limits or filters. The authors assessed English readability by using Flesch-Kincaid Reading Grade Level, Flesch Reading Ease Score, Gunning Fog Index, Coleman-Liau index, automated readability index, and Simple Measure of Gobbledygook (SMOG) index. The authors calculated readability for Spanish by using the Fernandez-Huerta index and INFLESZ (Ines-Barrio). Results: The authors assessed the first 100 consecutive sites identified with each search strategy and selected 117 sites. Readability scores for English-language sites were in the category of normal to read, easily understood by 13- through 15-year-old students (Flesch Reading Ease Score, 63, interquartile range (IQR) [53.9-66.2]; Gunning Fog Index, 10.4, IQR [8.8-12]; Coleman-Liau index, 12.5, IQR [11.6-13.3]; and automated readability index, 8.6, IQR [6.7-9.8]). SMOG results led to the estimation that only 7 years of education would be needed to understand these contents (SMOG, 7.6, IQR [6.5-8.8]). Spanish-language sites had a readability index normal for an adult, equivalent to a seventh or eighth school year (Fernandez-Huerta, 62.3, IQR [59.7-66.6]; INFLESZ, 57.5, IQR [55.1-62.1]). The authors found that 36.6% of English-language sites had some degree of difficulty for readers to understand their contents, whereas 23% of Spanish-language sites had some degree of difficulty (14.46; 95% confidence interval, −3.16 to 30.08). Conclusions: Spanish- and English-language electronic health information about endodontic treatment is acceptable to read, but—particularly for English-language sites—there is an important proportion of sites scoring difficulty levels well above the recommendations. Practical Implications: The internet is a useful tool for communicating with patients, but available endodontic information is difficult for laypeople to understand. Endodontists should produce relevant materials in plain language to overcome this problem.

Surgical extrusion should be considered as an alternative treatment in patients with structurally compromised teeth that retain coronal integrity and have favorable root anatomy. The procedure described is straightforward and can be performed quickly. A situation in which it was used to treat a maxillary premolar with substantial structural loss but well-preserved periodontal attachment is presented. The biologically oriented preparation technique is a conservative method of tooth restoration.

Background One of the causative factors of root defects is the increased friction produced by rotary instrumentation. A high canal curvature may increase stress, making the tooth more susceptible to dentinal cracks. The purpose of this study was to evaluate dentinal micro-crack formation with the ProTaper NEXT and ProTaper Universal systems using LED transillumination, and to analyze the micro-crack generated at the point of maximum canal curvature. Material and Methods 60 human mandibular premolars with curvatures between 30–49° and radii between 2–4 mm were used. The root canals were instrumented using the Protaper Universal® and Protaper NEXT® systems, with the aid of the Proglider® system. The obtained samples were sectioned transversely before subsequent analysis with LED transillumination at 2 mm and 8 mm from the apex and at the point of maximum canal curvature. Defects were scored: 0 for no defects; and 1 for micro-cracks. Results Root defects were not observed in the control group. The ProTaper NEXT system caused fewer defects (16.7%) than the ProTaper Universal system (40%) (P

Background: Irrigation of the root canal system is an essential step in the endodontic treatment. The aim of this article is to introduce continuous apical negative-pressure ultrasonic irrigation (CANUI), a new irrigation concept, and compare the characteristics of this new technique with current devices for activating the irrigant. Material and Methods: CANUI is designed for cleaning and disinfecting the root canal system. The device consists of a tube inside another tube that allows the continuous ultrasonic exchange of fresh irrigant, as the irrigant is simultaneously aspirated apically. The coronal and apical tubes are 0.75 and 0.3 mm in diameter, respectively. It is composed of a nickel-titanium microcannula suitable for the working length of curved canals. Results: The CANUI technique has the advantages of apical negative pressure (to avoid apical extrusion of the irrigant) and continuous ultrasonic irrigation (continuous refreshment of the irrigant and forced introduction into the canal ramifications). Conclusions: The CANUI technique could improve the irrigation technique of dentists to reach more disinfection in endodontic treatments. Key words:Apical negative pressure, continuous ultrasonic irrigation, irrigation in curved canals, irrigation systems.

BACKGROUND The efficacy of endodontic irrigation procedures can be compromised by the complexity of the root canal system. Delivering irrigants to the apical third of curved canals presents a particular challenge to endodontists. This study compared the effects of two ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of curved roots in extracted teeth. MATERIAL AND METHODS Two sets of simulated lateral canals were created at 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360 canals). The teeth were randomly divided into three experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). To assess the irrigation solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the curved root canals. The penetration of contrast solution into the simulated lateral canals was scored by counting the number of lateral canals (0-2) penetrated to at least 50% of the total length. RESULTS The CUI group showed significantly higher (P < 0.05) irrigant penetration into the lateral canals and into the apical third of the main canals. The PPI group showed significantly lower sodium hypochlorite penetration (P < 0.001) into the main and lateral canals compared with that in the CUI and PUI groups. Significantly higher irrigant penetration was observed in the PUI group than the PPI group. CONCLUSIONS Using CUI as the final rinse significantly increased the penetration of irrigant solution into the simulated lateral canals and apical third of curved roots. Key words:Continuous ultrasonic irrigation, curved root canals, passive ultrasonic irrigation, positive pressure irrigation, root canal irrigation.