Electrochemical Properties of Nickel-Titanium Rotary Endodontic Instruments.

Introduction: Nickel-titanium rotary endodontic files have been commercially available for decades, but more recent innovations have introduced heat-treated and surface-treated files. This study investigated the corrosion properties of various nickel-titanium files in normal saline and sodium hypochlorite (NaOCl).

Methods: Ten different file brands of size 40 with a 0.

12-Month flexural mechanical properties of conventional and self-adhesive flowable resin composite materials.

The aim of this study was to investigate the 12-month flexural mechanical properties of 23 flowable resin-based composites (FRBC) that included 5 self-adhesive FRBC materials. Specimens were evaluated following ISO 4049:2019 guidelines, but additionally stored in physiologic 0.2M phosphate buffered saline solution being tested at 24 h, 1 week, 1 month, and at 3-, 6-, 9-, and 12-months.

Sports mouthguard overview: Materials, fabrication techniques, existing standards, and future research needs.

Sports mouthguards are proven devices that reduce both the probability of and damage to orofacial tissues. While commonly used, clinicians may be unaware of the different sports mouthguard materials, proposed fabrication techniques, design recommendations, and newer digital fabrication methods. An overview of existing sports mouthguard standards is presented.

Dislodgement pushout resistance of five bioceramic root-end filling materials.

This study evaluated the dislodgement push-out resistance of five bioceramic materials. One hundred single-rooted teeth with one canal had the apical 3 mm and crown resected to create a 14 mm standardized length. The canals were instrumented to an apical size 80 with a 3 mm root-end preparation made with ultrasonic diamonds.

Long-Term Water Balance Evaluation in Glass Ionomer Restorative Materials.

The complex role of water in glass ionomer cement (polyalkenoate) dental restorative materials has been studied, but much of the present understanding concerning water balance within these materials is based on very early studies and short-term experiments. This study evaluated the nature of the water species of six conventional and four resin modified glass ionomer restorative materials over 3 years using thermogravimetric analysis techniques. Materials were prepared, placed in crucibles, and stored in physiologic phosphate buffered saline and evaluated at 24 h, 1 week, and then at 1, 3, 6, 9, 12, 18, 24, 30 and 36 months.

Three-dimensional Change of Elastomeric Impression Materials During the First 24 Hours: A Pilot Study.

Objectives: To evaluate the three-dimensional (3D) changes of three elastomeric impression materials using a novel measurement method for the first 24 hours after preparation.

Methods And Materials: Three impression materials consisting of a low-viscosity polyvinyl siloxane (PVS) (Aquasil LV, Dentsply Sirona, Charlotte, NC, USA) and two vinyl polyether silicone (VPES) materials consisting of a light body (EXA'lence LB, GC America, Alsip, IL, USA) and monophase (EXA'lence Monophase, GC America) materials were used in this study. All materials were prepared following manufacturer's recommendations with approximately 1-2 millimeters of material placed on the measurement pedestal of a calibrated noncontact, video imaging based, volumetric change measuring device (AcuVol ver 2.

Effect of post-irradiation polymerization on selected mechanical properties of six direct resins.

This study evaluated the post-irradiation mechanical property development of six resin composite-based restorative materials from the same manufacturer starting at 1 h post irradiation, followed by 24 h, 1 week, and 1 month after fabrication. Samples were stored in 0.2M phosphate buffered saline until testing.

The effect of endodontic access preparation on the failure load resistance of a 3Y-TZP monolithic zirconia crown.

The effect of endodontic access preparation on the failure load resistance of 3Y-TZP zirconia crowns was accomplished by preparing human molars and luting monolithic zirconia crowns with a self-adhesive resin cement. Besides the intact control, teeth received endodontic access preparations and then grouped (n = 12) into a positive control (no access repair), dentin core replacement only and complete access repair groups. Specimens were axially tested until failure with results of no significant difference between the failure load of intact controls and the complete access repair group.

Hardness Development in Resin Composite Core Materials.

Purpose: To investigate the hardness characteristics of 13 contemporary resin core materials.

Materials And Methods: Specimens (n = 12) were fabricated using stainless steel molds with top surfaces of dual-cure products photopolymerized while additional groups were allowed to self-cure. Twelve Knoop hardness indentations 500 microns apart were obtained of photopolymerized top and bottom sample surfaces as well as the self-cured sample surface with the mean recorded as the representative sample hardness.

24 hour polymerization shrinkage of resin composite core materials.

Purpose: The study's purpose was to evaluate the 24-hour polymerization shrinkage of resin composite core materials.

Material And Methods: Eleven resin composite core material samples (n = 12) were evaluated using a non-contact imaging device with measurements obtained over 24 h. Shrinkage values were determined corresponding to proposed times involved with CAD/CAM same-day treatment and at 24 h.

Anesthesia and Perioperative Considerations for Patients With Myasthenia Gravis.

Patients with neuromuscular diseases such as myasthenia gravis can present as complicated anesthetic cases. This article reviews anesthetic considerations for optimal perioperative care of patients with myasthenia gravis. The pathophysiology of myasthenia gravis, cholinergic and myasthenic crises, and perioperative management are discussed; this includes the pharmacology of acetylcholinesterase inhibitors vs sugammadex, extubation criteria, pain management, and risk factors for postoperative myasthenic crisis.

Methacrylate perspective in current dental practice.

Objective: To provide a current perspective concerning dental personnel sensitivity to methacrylate materials.

Overview: Methacrylate related sensitivity and allergies are currently beyond traditional thoughts concerning denture base resins and methyl methacrylate provisional materials. Methacrylates are now ubiquitous in current dental practice and dental personnel should be aware that dental adhesives contain potent sensitizers that may also cross-sensitize individuals to other methacrylates not experienced.

Flexural Performance of Direct Resin Composite Restorative Materials Past Expiration Date.

Objective:  This study' s purpose was to examine the flexural properties of five direct restorative resin composites stored up to 30 months after the expiration date.

Materials And Methods:  Ambient-stored materials had pre-expiration date baseline flexure strength values as per ISO 4049 ( = 20). All materials were used per manufacturer guidelines, photopolymerized on both sides using a LED-based visible light curing unit, and stored in 0.

Microtomographic Analysis of Resin Composite Core Material Porosity.

Purpose: To nondestructively evaluate the porosity of ten contemporary resin composite core materials using microtomographic (microCT) analysis.

Material And Methods: Resin composite core material samples (n = 12) including dual-cure, visible light cure only, and a self-cure material were fabricated using a standardized mold following manufacturer's recommendations. After storage in phosphate buffered saline for one week, specimens were analyzed using a microCT unit at 5.

Effect of Molar Preparation Axial Height on Retention of Adhesively-luted CAD-CAM Ceramic Crowns.

Purpose: To evaluate the effect of axial wall height (AWH) on failure resistance of CAD-CAM adhesively-bonded, all-ceramic crowns on molar preparations with a conservative total occlusal convergence (TOC).

Materials And Methods: 60 newly extracted maxillary third molars were divided into 5 groups (n = 12) and prepared for all-ceramic crowns with occlusal cervical AWH of 0, 1, 2, 3, and 4 mm, all containing a conservative 10-degree TOC. Scanned preparations were fitted with lithium-disilicate glass-ceramic crowns using a self-adhesive resin-composite luting agent after intaglio surface preparation with hydrofluoric acid and silane.

Fracture resistance of all-ceramic crowns based on different preparation designs for restoring endodontically treated molars.

Objectives: To evaluate endodontically treated molar fracture resistance restored with CAD/CAM lithium disilicate (LDS) crowns with different amalgam core preparation design.

Materials And Methods: Eighty-four recently extracted mandibular third molars were divided into seven groups (n = 12) and embedded in autopolymerizing resin. Coronal tooth structure was removed, pulp chamber exposed, and pulpal remnants removed.

Physical property investigation of contemporary glass ionomer and resin-modified glass ionomer restorative materials.

Objectives: The objective of this study was to investigate selected physical properties of nine contemporary and recently marketed glass ionomer cement (GIC) and four resin-modified glass ionomer cement (RMGI) dental restorative materials.

Materials And Methods: Specimens (n = 12) were fabricated for fracture toughness and flexure strength using standardized, stainless steel molds. Testing was completed on a universal testing machine until failure.

Effect of Premolar Axial Wall Height on Computer-Aided Design/Computer-Assisted Manufacture Crown Retention.

Purpose: To evaluate the effect of premolar axial wall height on the retention of adhesive, full-coverage, computer-aided design/computer-assisted manufacture (CAD/CAM) restorations.

Materials And Methods: A total of 48 premolar teeth randomized into four groups (n = 12 per group) received all-ceramic CAD/CAM restorations with axial wall heights (AWH) of 3, 2, 1, and 0 mm and 16-degree total occlusal convergence (TOC). Specimens were restored with lithium disilicate material and cemented with self-adhesive resin cement.

Bicuspid Axial Wall Height Effect on CAD/CAM Crown Fracture Mode on Preparations Containing Advanced Total Occlusal Convergence.

Purpose: To evaluate bicuspid axial wall height effect on the fracture mode of adhesively luted, all-ceramic CAD/CAM crowns with a 20° total occlusal convergence (TOC).

Materials And Methods: Recently extracted premolars were randomly divided into 4 groups (n = 12) with all-ceramic crown preparations accomplished using a high-speed handpiece inserted into a milling device. Specimens were prepared containing occlusogingival axial wall heights of 3, 2, and 1 mm as well as a group containing a flat preparation surface with no axial wall height.

Failure load effect of molar axial wall height with CAD/CAM ceramic crowns with moderate occlusal convergence.

Objectives: To evaluate the significance of axial wall height (AWH) in molar fracture resistance involving CAD/CAM adhesively bonded, all-ceramic full coverage restorations on preparations with moderate total occlusal convergence (TOC) (16°).

Materials And Methods: 60 newly extracted maxillary third molars were divided into 5 groups (n = 12). Specimens were prepared for full-coverage, all ceramic restorations with occlusal cervical AWHs of 4, 3, 2, 1 as well as a flat preparation (0 mm AWH) with all preparations with AWH containing a moderate 16° TOC.

Preparation Ferrule Design Effect on Endocrown Failure Resistance.

Purpose: To evaluate the effect of preparation ferrule inclusion with fracture resistance of mandibular molar endocrowns.

Materials And Methods: Recently extracted mandibular third molars were randomly divided into 3 groups (n = 12) with the coronal tooth structure removed perpendicular to the root long axis approximately 2 mm above the cemento-enamel junction with a slow-speed diamond saw. The pulp chamber was exposed using a diamond bur in a high-speed handpiece with pulpal remnants removed and canals instrumented using endodontic hand instruments.

Effect of surface treatments on the mechanical properties and antimicrobial activity of desiccated glass ionomers.

Objectives: The purpose of this study was to evaluate the effect of various surface treatments on the mechanical properties and antibacterial activity of desiccated glass-ionomer (GI) and resin-modified glass-ionomer (RMGI) materials.

Methods: One hundred GI and RMGI specimens were fabricated in a mold, stored in 100% humidity for 24h, placed in air to desiccate for 24h, and then stored for one week in one of the five media [casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), chlorhexidine (CHX), sodium fluoride (NaF), cetylpyridinium chloride (CPC), or 100% humidity (control)]. Fifty GI and RMGI specimens were tested in flexure to determine flexural strength and modulus, with the fragments used for Knoop hardness testing.

Selected physical properties of new resin-modified glass ionomer luting cements.

Statement Of Problem: Two resin-modified glass ionomer (RMGI)-based luting agents have been recently marketed without independent reports of their physical properties.

Purpose: The purpose of this in vitro study was to evaluate selected physical properties of 2 newly marketed RMGI luting agents and compare the findings with traditional materials.

Material And Methods: Specimens (N=12) of Nexus RMGI, UltraCem, GC Fuji Cem 2, and RelyX Luting Plus were fabricated using standardized molds for flexural strength and fracture toughness according to manufacturer recommendations and stored in physiologic phosphate-buffered saline solution at 37°C until testing.

A Comparison of Coronal Tooth Discoloration Elicited by Various Endodontic Reparative Materials.

Introduction: The purpose of this study was to evaluate coronal tooth discoloration of ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN), white ProRoot MTA, EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), MTA Angelus (Angelus Solucoes Odontologicas, Londrina, Brazil), and Biodentine (Septodont, Saint Maur des Fosses, France) when used in an ex vivo pulpotomy model.

Methods: Freshly extracted mandibular third molars were collected and stored in 1% chloramine-T solution. Teeth were randomly assigned into 6 groups (n = 15) and stored individually in phosphate buffered saline at 37 °C in 100% humidity.