Effects of a pre-enlargement on fracture incidence of reused reciprocating instruments: A clinical study.

This study assessed the impact of pre-enlarging the root canal using a size 25 K-file on the fracture incidence of three reciprocating instruments after multiple uses. After a glide path performed with a size 15 K-file, the instruments (Reciproc R25, Reciproc Blue R25, and WaveOne Gold Primary) were initially used in 936 root canals. Then, for the second and third uses (933 and 927, respectively), a pre-enlargement using a size 25 K-file at the working length was done.

Micro-computed tomographic evaluation of dentinal microcracks in response to progressive taper enlargement in root canals of maxillary molars.

Aim: To investigate the development of dentinal microcracks resulting from the progressive enlargement of the buccal canals of maxillary molars with and without the MB2 canal employing instruments with the same tip and four different tapers.

Methodology: Twenty maxillary molars with (n = 10) and without (n = 10) the MB2 canal underwent micro-CT scanning. Their mesiobuccal and distobuccal canals were sequentially enlarged using nickel-titanium instruments with sizes 25/.

Maxillary Dental Anatomy and Physiology: Endodontic and Periodontal.

The maxillary sinus floor is formed by the alveolar process of the maxilla. Frequently, the roots of maxillary molars and premolars may protrude into the sinus cavity, with only a thin membrane separating them. Endodontic infections are characterized by mixed biofilms of anaerobic and proteolytic bacteria that can infect the root canal space and accessory anatomy of those teeth producing apical periodontitis.

Dental Pathophysiology of Odontogenic Sinusitis: Endodontic Infections.

Bacterial odontogenic sinusitis (ODS) arises from maxillary dental issues or oral procedures, and affects at least the maxillary sinuses, with or without other paranasal sinus involvement. It has been historically underreported, in contrast to more recent findings attributing 25-40% of chronic maxillary sinusitis to dental causes. Endodontic infections represent one of the most common causes of ODS.

Multimethod Analysis of a Novel Multi-coloured Heat-treated Nickel-Titanium Rotary System: Design, Metallurgy, Mechanical Properties, and Shaping Ability.

Introduction: This study aimed to compare a new multicolored rotary system with four heat-treated rotary instruments using the multimethod approach.

Methods: Three-hundred instruments of RCS Rainbow, Rotate, RaCe EVO, OneCurve, and ProTaper Ultimate systems were evaluated regarding their design (stereomicroscopy, scanning electron microscopy, and 3D surface scanning), metallurgy, and mechanical performance (cyclic fatigue, torsional resistance, bending and buckling resistance, and cutting ability). Unprepared surfaces after canal preparation of maxillary molars were evaluated using micro-computed tomography.

Exploring access cavity through non-carious cervical lesions: Impacts on instrumentation, obturation, and fracture resistance in mandibular incisors.

Aim: To compare the effects of Cervical Access Cavity (CervAC) and Traditional Access Cavity (TradAC) on root canal preparation, root canal filling, and fracture resistance in mandibular incisors.

Methodology: Twenty recently extracted and intact mandibular incisors were initially scanned using a micro-CT device. The specimens were anatomically matched to create two groups (n = 10).

Dynamic Photoelastic Analysis of Stress Distribution in Simulated Canals Using Rotary Instruments with Varied Tip and Taper Sizes: A Quasi-3D Approach.

Introduction: To compare the stress produced on the walls of simulated canals by rotary instruments with varied tip and taper sizes.

Methods: Ninety isotropic transparent blocks, each containing a 60-degree curved canal, were distributed into 18 groups (n = 5) based on the instrument tip (sizes 10, 15, 20, 25, 30, and 35) and taper (sizes 0.02, 0.

Comprehensive Assessment of Cyclic Fatigue Strength in Five Multiple-File Nickel-Titanium Endodontic Systems.

The resistance of nickel-titanium endodontic instruments against cyclic fatigue failure remains a significant concern in clinical settings. This study aimed to assess the cyclic fatigue strength of five nickel-titanium rotary systems, while correlating the results with the instruments' geometric and metallurgical characteristics. A total of 250 new instruments (sizes S1/A1, S2/A2, F1/B1, F2/B2, F3/B3) from ProTaper Gold, ProTaper Universal, Premium Taper Gold, Go-Taper Flex, and U-Files systems underwent mechanical testing.

Effects of increasing instrument size and taper on the disinfection and shaping of mandibular incisors.

This study assessed canal preparation effects on disinfection and dentin preservation. Thirty mandibular incisors were paired into two experimental groups (n = 10). Following contamination, the initial microbial sample was collected.

Clinical strategies for successful palato-mesiobuccal canal management-Report of 2 cases.

Aim: To describe the management of the palato-mesiobuccal (PMB) canal in maxillary second molars with fused roots using conventional techniques.

Summary: Root canal treatment success hinges upon effectively addressing the intricate and variable anatomy of molar teeth. Failure to do so can lead to persistent infections and treatment failure.

Multimethod analysis of large- and low-tapered single file reciprocating instruments: Design, metallurgy, mechanical performance, and irrigation flow.

Aim: To compare eight large- and low-tapered heat-treated reciprocating instruments regarding their design, metallurgy, mechanical properties, and irrigation flow through an in silico model.

Methodology: A total of 472 new 25-mm E-Flex Rex (25/.04 and 25/.

Worldwide Anatomic Characteristics of the Mandibular Canine-A Multicenter Cross-Sectional Study with Meta-Analysis.

Introduction: This study aimed to examine the global prevalence of root and root canal morphologies in mandibular canines and analyze potential influences of region, ethnicity, sex, and age on the proportion of a second root and root canal configuration.

Methods: Observers from 44 countries screened 13,200 canines using cone-beam computed tomographic exams and gathered data on the percentages of 2 root canal morphologies and 2-rooted configurations (primary outcomes), as well as the root canal configurations (secondary outcome). Demographic factors (ethnicity, sex, and age) were collected for each participant.

Worldwide Assessment of the Root and Root Canal Characteristics of Maxillary Premolars - A Multi-center Cone-beam Computed Tomography Cross-sectional Study With Meta-analysis.

Introduction: This worldwide study examined the root and root canal characteristics of maxillary premolars and explored how demographic factors impact the outcomes.

Methods: Observers from 44 countries assessed 26,400 maxillary premolars using cone-beam computed tomography and employed a standardized screening method to gather data on multiple canal morphology and 3-rooted configuration (primary outcomes), as well as secondary outcomes related to root and root canal anatomies. Demographic factors such as ethnicity, sex, and age were collected for each participant.

The impact of long-term storage conditions on the development of experimental dentinal microcracks.

This study evaluated the impact of long-term storage conditions (medium and time) on the development of experimental dentinal microcracks through micro-computed tomography. Sixty freshly extracted premolars were stored in formalin, water, or dry conditions (n = 20) and scanned after 72 h, 30 days, 6 months and 3 years of extraction. The effect of the storage medium and time on the occurrence of dentinal defects was statistically evaluated.

Exploring the Efficacy of 6 Preparation Systems for Achieving Minimal Root Canal Transportation: A Micro-CT Investigation.

Introduction: This study aimed to assess the canal transportation with 6 preparation systems.

Methods: Sixty curved mesial roots of mandibular molars were scanned, and their root canals (n = 20 per group) were prepared with XP-endo Shaper, BioRace, ProTaper Next, Twisted File Adaptive, Reciproc, or Reciproc Blue systems. After preparation, a new scan was conducted, and transportation was determined by comparing the geometric center of the canal in 13,542 cross-sectional slices.

Characterization of four heat-treated reciprocating instruments: Design, metallurgy, mechanical performance, and irrigation flow patterns.

Aim: To compare the design, metallurgy, and mechanical properties of four heat-treated reciprocating instruments coupled with the evaluation of the irrigation flow using an in silico model.

Methodology: New EdgeOne Fire Primary, Easy-File Flex Regular 25, WaveOne Gold Primary and Reciproc Blue R25 instruments (n = 124) were initially evaluated regarding their design through stereomicroscopy, scanning electron microscopy and 3D surface scanning. In addition, energy-dispersive X-ray spectroscopy was utilized to determine their elemental composition, and differential scanning calorimetry tests to evaluate their phase transformation temperatures.

To flat or not to flat? Exploring the impact of flat-side design on rotary instruments using a comprehensive multimethod investigation.

Aim: To assess the influence of a flat-side design on the geometry, metallurgy, mechanical performance and shaping ability of a novel nickel-titanium rotary instrument.

Methodology: Sixty-five new 25-mm flat-side rotary instruments (size 25, taper 0.04) and their nonflat-side prototypes (n = 65) were assessed for major deformations and examined regarding macroscopic and microscopic design, determination of nickel and titanium elements ratio, measurement of phase transformation temperature and evaluation of mechanical performance parameters including time/cycles to fracture, maximum torque, angle of rotation, maximum bending and buckling strengths and cutting ability.

Quasi-3D dynamic photoelastic analysis of stress distribution during preparation of simulated canals with 13 mechanical preparation systems.

Aim: The aim of this study is to compare the stress produced on the internal walls of simulated canals by nine rotary and four reciprocating systems.

Methodology: Sixty-five isotropic transparent blocks containing a 60° curved and tapered simulated canal were selected and distributed into 13 groups (n = 5) according to the preparation system: BioRace, HyFlex EDM, iRaCe, Mtwo, One RECI, ProTaper Next, RaCe EVO, Reciproc, Reciproc Blue, R-Motion, VDW.ROTATE, XP-Endo Rise Shaper, and XP-Endo Shaper.

Effect of the progressive taper enlargement of buccal root canals of three-rooted maxillary molars: A stepwise micro-CT study.

This study evaluated unprepared canal areas, volume of dentine removal, and dentine thickness after the progressive enlargement of the buccal canals of 22 maxillary molars, with and without the MB2, using instruments with the same tip size (0.25 mm) but 4 different tapers (0.03, 0.

Success rate of permanent teeth pulpotomy using bioactive materials: A systematic review and meta-analysis of randomized clinical trials.

Background: The results of vital pulp treatments in permanent teeth have been encouraging. Currently, pulpotomy treatment for permanent teeth primarily utilizes mineral trioxide aggregate (MTA) as the dressing material, followed by calcium hydroxide. While other calcium-silicate-based cements have been suggested for pulpotomy, there is a limited number of studies evaluating their long-term effectiveness.

Age-related changes in the morphology of the root canal system of mandibular first molars: a micro-CT study.

Objective: This study aimed to evaluate changes on root canal morphology in patients with different ages using micro-CT technology.

Materials And Methods: Mandibular first molars (n = 150) were scanned at a pixel size of 13.68 µm, categorized into 3 groups according to patient's age and analyzed regarding configuration, orifices, apical foramina, root length, canal volume, and surface area.