Do instrument kinematics and the apical preparation limit influence canal disinfection and bacterial extrusion?

This in vitro research assessed the influence of the instrument kinematics (rotary and reciprocating) and the apical preparation limit on the root canal disinfection and apical bacterial extrusion. After 21 days of Enterococcus faecalis biofilm formation in 72 mesial root canals of mandibular molars, the root canals were distributed into 2 groups (n = 36) according to the systems used for preparation: ProDesign S and Reciproc. The groups were redistributed according to the limit of apical preparation (n = 11): (a) 1 mm up to the apical foramen (TL-1); (b) at the apical foramen (TL = 0); (c) 1 mm beyond the apical foramen (TL + 1).

Effect of final irrigation protocols on the structural integrity and mechanical properties of the root dentine.

This study compared the effects of different final irrigation protocols on the mechanical properties and structural integrity of root dentine. One-hundred eight teeth were instrumented and irrigated with sodium hypochlorite (NaOCl) using conventional irrigation (CI). Teeth were distributed into four groups based on final irrigation protocols: Control Group (CG): 17%EDTA/CI + H2O; G1: 2.

Do the apical limit and diameter of the instrumentation influence the extrusion of sodium hypochlorite solution? A micro-CT study.

This study evaluated the influence of the apical limit and the diameter of the instrumentation on the extrusion of the irrigating solution. Sixty human lower premolars were distributed into 5 groups according to the apical limit and diameter of the root canal instrumentation (n = 12): (G-1) R40 instrument 1 mm above the tooth length (TL) (Control); (G-1) R50 instrument 1 mm above the TL; (GF) R25 instrument at the TL; (GF) R40 instrument at the root canal length and (GF) R50 instrument at the TL. A space of 33.

Ultrasonic activation of adhesive systems increases bond strength and intratubular penetration of resin cement in root dentin subjected to radiation therapy.

Objective: This study aimed to evaluate the effect of ultrasonic activation of etch-and-rinse and self-etch adhesive systems on the bond strength of resin cement to irradiated root dentin.

Materials And Methods: Eighty human maxillary anterior teeth were distributed into 8 groups (n = 10), according to the type of adhesive system used (etch-and-rinse and self-etch), the ultrasonic activation of the adhesive systems, and the dentin condition (irradiated or non-irradiated - 70 Gy). Endodontic treatment was performed followed by fiberglass post-space preparation.

Assessment of multispecies biofilm growth on root canal dentin under different radiation therapy regimens.

Objectives: To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens.

Materials And Methods: Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55 Gy; and RT70) 70 Gy.

Longer light-curing time decreases the effect of ageing on composite resin hardness used in root reinforcement.

This study evaluated the hardness of a composite resin used for root reinforcement, considering the light-curing time, root canal region and ageing due to long-term storage. Twenty incisor roots were reinforced using composite resin, varying the photopolymerisation time (40 or 120 s). Following fibre post cementation, the roots were transversely sectioned into coronal, middle and apical regions.

Effect of the timing of primary endodontic treatment and dosage of radiation therapy on the filling material removal.

This study investigated the effect of the timing of primary endodontic treatment and dosage of radiotherapy on the remaining filling material (RFM) during endodontic reintervention. 60 single-rooted human mandibular premolars were distributed into five groups (n = 12), according to the timing and dosage of radiation (55Gy or 70Gy): NegativeCG-non-irradiated teeth; Endo-pre-RT-obturation before irradiation (55Gy or 70Gy); Endo-post-RT-obturation and reintervention after irradiation (55Gy or 70Gy). Roots were cleaved and analysed under stereomicroscope and Scanning Electron Microscope to quantify (%) the RFM.

Comparative Analysis of AH Plus Bond Strength to Root Canal Dentin and Adhesive Interface Quality after Calcium Hydroxide Removal using Different Irrigation Protocols.

Introduction: To evaluate the push-out bond strength (POBS) of AH Plus sealer to root dentin and the adhesive interface quality after calcium hydroxide (Ca(OH)) intracanal dressing removal with different final irrigation protocols.

Method: After root canal instrumentation and irrigation, 40 root canals were filled with Ca(OH) and sealed. After 14 days, the specimens were randomly distributed according to the irrigation protocols for Ca(OH) removal (n = 10): G (control) - distilled water; G - 1% NaOCl; G - 17% EDTA; G - 17% EDTA + 1% NaOCl.

How Does Intentional Apical Foraminal Enlargement Affect the Foramen and Root Canal Morphology?

Introduction: This study assessed the effect of intentional foraminal enlargement on the foramen and the apical root canal morphology.

Method: Sixty mesial roots of mandibular molars were scanned by micro-computed tomography. Their apical foramina were photographed with a stereomicroscope before and after preparation.

Ultrasonic activation of the endodontic sealer enhances its intratubular penetration and bond strength to irradiated root dentin.

To evaluate the effect of ultrasonic activation of the endodontic sealer on its intratubular penetration and bond strength to irradiated root dentin. Forty human teeth were distributed into 4 groups (n = 10), according to the radiation therapy (RT) exposure-70 Gy-and ultrasonic activation (UA) of the endodontic sealer: RT/UA-irradiated teeth and sealer UA; RT/no-UA-irradiated teeth and no sealer UA; no-RT/UA-non-irradiated teeth and sealer UA and no-RT/no-UA-non-irradiated teeth and no sealer UA. Push-out bond strength test was performed in a Universal Testing Machine.

The effects of heating on the physicochemical properties of tricalcium silicate root canal sealers.

This study evaluated the effect of heating on the physicochemical properties and surface changes of tricalcium silicate sealers. Three tricalcium silicate root canal sealers (Bio-C Sealer, BioRoot-RCS, EndoSequence BC Sealer), and one epoxy resin-based sealer (AH Plus; control) were tested. The effect of heating on setting time (ST) and flowability were assessed according to ANSI/ADA 57 and ISO 6876 standards.

Did in-between rinsing and agitating with distilled water prevents precipitate formation by the interaction between sodium hypochlorite and chlorhexidine canal irrigants?

The interaction of sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) produces an orange-brown precipitate. The present study evaluated the influence of distilled water (H O) in different irrigation protocols designed to prevent the formation of precipitate with NaOCl and CHX. Fifty canine teeth were instrumented and split longitudinally.

Tip and taper compatibility of accessory gutta-percha points with rotary and reciprocating instruments.

Objectives: This study was conducted to evaluate and compare the tip and taper compatibility of accessory gutta-percha points (AGPs) with various rotary and reciprocating instruments.

Materials And Methods: Using a profile analyzer, tip and taper measurements were taken of 10 AGPs of each of the 14 models available from Odous de Deus and the 4 models available from Dentsply-Maillefer. Diameter measurements were taken at 1-mm intervals, from 3 mm from the tip (D3) to 16 mm.

Evaluation of changes in root canal length and accuracy of the electronic apex locator during different stages of endodontic treatment and retreatment.

This study evaluated changes in the root canal length (RCL) and the accuracy of the electronic apex locator (EAL) during the different stages of endodontic treatment and retreatment. Fifty-six mesial root canals of mandibular molars were selected. The actual root canal length (AL) of the canals was obtained by inserting a size 15 hand file up to the apical foramen, under magnification.

Effectiveness of different supplementary protocols for remaining filling material removal in endodontic reintervention: an integrative review.

The aim of this study was to perform an integrative review to identify the most effective supplementary protocols used after filling material (FM) removal and root canal reinstrumentation, during endodontic reintervention. The literature search was performed on the electronic databases PubMed and Latin American and Caribbean Health Sciences Literature (LILACS), using a combination of specific scientific descriptors. Selection criteria accepted articles published in English, Spanish and Portuguese languages, up to August 2021, involving in vitro and ex vivo studies.

Prevalence of postoperative pain after endodontic treatment using low and high concentrations of sodium hypochlorite: a systematic review and meta-analysis.

Objectives: To determine the prevalence of postoperative pain after endodontic treatment using low (LC) and high (HC) concentrations of sodium hypochlorite (NaOCl).

Materials And Methods: Six databases and the grey literature were searched to identify randomized clinical trials that evaluated postoperative pain after endodontic treatment using NaOCl. NaOCl concentrations were dichotomized into 'LC' (0.

Dental and composite resin discoloration induced by different hydraulic calcium silicate-based cements: two-year in vitro assessment.

Few long-term studies assess the discoloration induced by hydraulic calcium silicate-based cement on dental structures. In addition, as far as we know, no long-term study has assessed the discoloration induced by these cement on composite resin. This in vitro study aimed to assess, during a period of two years, the discoloration potential of different hydraulic calcium silicate-based cements (hCSCs) on the enamel/dentin structure and composite resin restoration.

Effect of radiation therapy on fracture resistance of simulated immature teeth submitted to root reinforcement.

Background: The literature is scanty regarding the effect of radiation therapy (RT) on the mechanical properties of immature permanent teeth.

Aim: To evaluate the effect of RT on the fracture resistance of simulated immature teeth submitted to different types of root reinforcement.

Design: Sixty-four human teeth simulating the Cvek stage 3 of root development were distributed into eight groups (n = 8), according to exposure or not to RT (70 Gy) and the root reinforcement method: Group NR (control)-no reinforcement/no RT; Group NR + RT (control)-no reinforcement/RT; Group PO-tricalcium silicate-based cement (TS) apical plug/canal obturation/no RT; Group PO + RT-TS apical plug/canal obturation/RT; Group TS-canal filling with TS/no RT; Group TS + RT-canal filling with TS/RT; Group FP-TS apical plug/fibreglass post/no RT; and Group FP + RT-TS apical plug/fibreglass post/RT.

Evaluation of pH and calcium ions release of two tricalcium silicate-based sealers through roots of primary teeth.

Background: This study aimed to evaluate the pH and calcium ions (Ca) release from two tricalcium silicate-based sealers (Sealer Plus BC and Bio-C Pulpecto) through roots of primary teeth.

Methods: Forty root canals of primary incisors were prepared and distributed into four groups according to the filling material: G (Sealer Plus BC); G (Bio-C Pulpecto); G (Ultracal); and G (no filled). pH measurement was performed with a digital pH meter, and the Ca+ release was measured in an atomic absorption spectrophotometer at baseline, 24 h and 1, 2, 3, and 4 weeks later.

Impact of radiotherapy on the morphological and compositional structure of intra-radicular dentin.

Considering the side effects in the oral cavity and dental structures of radiotherapy (RDT) for head and neck cancer, this study aimed to evaluate the effects of RDT on the root dentin concerning the obliteration of dentinal tubules, the inorganic composition of intra-radicular dentin, and the integrity of collagen fibers. Thirty human canines were selected from a biobank and randomly divided into two groups (n=15). The samples were sectioned buccolingually, and a hemisection was used for structural analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS).

Physicochemical properties of a calcium aluminate cement containing nanoparticles of zinc oxide.

Objectives: This study evaluated the effect of different nanoparticulated zinc oxide (nano-ZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC).

Materials And Methods: The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventional-ZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (R), setting time (S), dimensional change (D), solubility (S), compressive strength (C), and pH were evaluated.

Analysis of physicochemical properties of endodontic sealers containing rhodamine B.

The use of fluorescent dyes in microscopy studies is frequent. Therefore, it is important to investigate whether these compounds may alter the physicochemical properties of materials in which they are incorporated to avoid methodological biases. This study evaluated the physicochemical properties of two endodontic sealers containing dry or diluted rhodamine B.

Development and validation of a method for creating incomplete vertical root fracture in extracted teeth.

The present study reported a method for inducing incomplete root fracture in human extracted teeth for the purpose of evaluating the merits of different diagnostic imaging techniques. Thirty-five single-rooted teeth were inspected under magnification and transillumination to exclude previously fractured teeth. Tooth crowns were removed, and the root canals were prepared up to the ProTaper Next X4 (40.

Effect of dental tissue thickness on the measurement of oxygen saturation by two different pulse oximeters.

This study aimed to evaluate the influence of different dental tissue thickness on the measurement of oxygen saturation (SpO2) levels in high (HP) and low (LP) blood perfusion by comparing the values obtained from two different pulse oximeters (POs) - BCI and Sense 10. Thirty freshly extracted human teeth had their crowns interposed between the POs and an optical simulator, which emulated the SpO2 and heart beats per minute (bpm) at HP (100% SpO2/75 bpm) and LP (86% SpO2/75 bpm) modes. Afterwards, the palatine/lingual surfaces of the dental crowns were worn with diamond drills.

Effect of the timing of radiation therapy on the push-out strength of resin cement to root dentine.

This study investigated the effect of radiation timing on the bond strength of resin cement to intraradicular dentine. Fifty human teeth were distributed into 5 groups (n = 10): Control (nonirradiated teeth), Before-RCT (teeth irradiated before root canal treatment), After-CH (teeth irradiated after canal preparation and placement of calcium hydroxide intracanal dressing), After-RCT (teeth irradiated after completion of root canal treatment) and After-FPL (teeth irradiated after luting of a glass fibre post). Each tooth received 70 Gy irradiation.