Effect of the Controlled Delivery of Chelating Agents on the Pulp Tissue Dissolution Ability of Fresh Sodium Hypochlorite Solutions.

Introduction: The purpose of this study was to evaluate pulp tissue dissolution ability of sodium hypochlorite (NaOCl) when mixed with tetrasodic etidronate (NaHEBP) and disodic ethylenediaminetetraacetate (NaEDTA) under controlled flow.

Methods: Bovine pulp tissue was extracted from the lower incisors of 10 bovine jaws. Pulp specimens were standardized in size (1 × 3 × 10 mm), blotted dry, and weighed (initial weight [T0]: mean (SD) = 31.

Full mapping tensile bond strength of luting in search for differences due to centripetal curing shrinkage.

Objectives: testing if hypothetical transverse centripetal strains due to polymerization contraction of luting materials produce differential alterations in its bonding to luted structures, depending on distances to the center of the luting mass, and if this effect is C-factor related. Two hypotheses were tested: (1) there is a statistically significant decreasing relationship between the bonding strength and the transverse distances to the center of the luting material, and (2) there is a statistically significant difference between bonding strengths among luting spaces with different configuration factors.

Methods: 10 PMMA (15 mm Ø) pairs of cylinders were cemented (Scotchbond Universal adhesive & Relyx Universal, both chemically cured) in a compliant setup under two (20 and 70 N) luting forces forming 2 groups (5 samples each), resulting in different C-factors.

Body temperature fatigue behaviour of reciprocating and rotary glide path instruments in sodium hypochlorite solutions alone or combined with etidronate.

The aim of the study was to compare cyclic fatigue (CF) resistance of reciprocating and rotary glide path instruments in the presence of irrigation solutions at body temperature. CF resistance of 100 instruments (50 ProGlider and 50 WaveOne Gold Glider) was tested in sodium hypochlorite solutions alone (NaOCl) or in combination with etidronate (NaOCl/HEBP). The CF platform with a simulated canal (curvature = 60°/radius = 3 mm) was submerged in a temperature-controlled bath with the solutions kept at 37 ± 1°C controlled by a precision mercury glass thermometer.

Effect of gamma-ray sterilization on phase transformation behavior and fatigue resistance of contemporary nickel-titanium instruments.

Objectives: The aim of this study was to compare body temperature cyclic fatigue resistance (CF) of heat-treated NiTi rotary instruments submitted to gamma-irradiation or autoclave sterilization.

Materials And Methods: A total of 176 instruments (88 Hyflex EDM (HEDM) and 88 TRUShape (TS)) were used. Forty-four of each were submitted to gamma-irradiation.

Resistance to cyclic fatigue of reciprocating instruments determined at body temperature and phase transformation analysis.

The purpose of this study was to compare cyclic fatigue (CF) resistance of reciprocating instruments at body temperature and relate the findings to their martensitic transformation temperatures. Contemporary nickel-titanium (NiTi) reciprocating instruments WaveOne Primary, WaveOne Gold Primary and EdgeFile X1 (n = 20 each and #25 tip diameter) were tested for CF resistance at body temperature (37 ± 1°C). Instruments were actioned according to manufacturer guidelines until fracture occurred in a simulated canal (angle of curvature = 60°, radius of curvature = 3 mm and centre of curvature = 5 mm from the tip).

Impact of a modified motion on the fatigue life of NiTi reciprocating instruments: a Weibull analysis.

Objectives: To evaluate the impact of a modified motion on the fatigue life of four brands of nickel-titanium (NiTi) reciprocating instruments.

Materials And Methods: Cyclic fatigue (CF) resistance of 160 instruments was evaluated in an artificial stainless-steel canal (90° angle, 5-mm radius of curvature). WaveOne and WaveOne Gold (Denstply Maillefer, Baillagues, Switzerland) and Reciproc and Reciproc Blue (VDW, Munich, Germany) were tested with two different motions: (1) X-Smart Plus (Denstply Maillefer) endodontic motor and (2) a 4:1 contra-angle with an experimental motion (EVO) with different rotation angles and based on a sinusoidal acceleration.

Variable impact by ambient temperature on fatigue resistance of heat-treated nickel titanium instruments.

Objectives: The purpose of this study was to evaluate the effect of different ambient temperatures on cyclic fatigue (CF) life of two NiTi rotary systems and correlate the results with martensitic transformation temperatures.

Materials And Methods: Heat-treated NiTi Vortex Blue (VB) and EdgeSequel Sapphire (SP) instruments (tip sizes no. 20, 25, 30, 35, 40) were tested for CF resistance at room and body temperature (n = 20 each group) in a simulated canal (angle of curvature 60°; radius 3 mm; center from instrument tip 4.

Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments.

Introduction: The aim of this study was to assess differences in cyclic fatigue (CF) life of contemporary heat-treated nickel-titanium rotary instruments at room and body temperatures and to document corresponding phase transformations.

Methods: Forty Hyflex EDM (H-EDM) files (Coltene, Cuyahoga Falls, OH [#25/.08, manufactured by electrical discharge machining]) and 40 TRUShape (TS) files (Dentsply Tulsa Dental Specialties, Tulsa, OK [#25/.

Differences in cyclic fatigue resistance between ProTaper Next and ProTaper Universal instruments at different levels.

Introduction: New designs and alloys have been developed to increase cyclic fatigue (CF) resistance of rotary files. The aim of this study was to compare CF resistance of ProTaper Universal (PTU; Dentsply Tulsa Dental, Tulsa, OK) and ProTaper Next (PTN, Dentsply Tulsa Dental) instruments at different points of curvature.

Methods: A total of 420 files (240 PTU, S1, F1, F2, and F3 and 180 PTN, X1, X2, and X3) were divided in 14 groups of 30 instruments each.

Prospective case controlled clinical study of post-endodontic pain after rotary root canal preparation performed by a single operator.

Objectives: The aim of this study was to assess the influence of the shaping technique on incidence, intensity, duration and type of postoperative pain (PP).

Methods: Root canal treatments were carried out with rotary instrumentation (n=80) during a single-visit, and data about pre-treatment conditions were collected. Patients were given a questionnaire to record the presence or absence of post-endodontic pain, its duration and level of discomfort.

Microtensile bond strength test bias caused by variations in bonded areas.

Purpose: While it has been shown that no method produces specimens with exactly the same cross-sectional bonded area (BA), BA variations within and between studies are a well-known covariate in microtensile test results. However, no method has yet been described to accurately account for its influence. A procedure is presented that allows controlling for variations of BA effects on results.

Cyclic fatigue resistance of K3, K3XF, and twisted file nickel-titanium files under continuous rotation or reciprocating motion.

Introduction: New designs and alloys and different motions have been introduced to increase the cyclic fatigue (CF) resistance of nickel-titanium (NiTi) files. The aim of this study was to compare the CF resistance of K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and TF (SybronEndo) files under continuous rotation and reciprocating motion.

Methods: A total of 210 files (30-tip diameter, 0.

Differences in cyclic fatigue resistance at apical and coronal levels of Reciproc and WaveOne new files.

Introduction: Recent improvements in alloys, kinematics, and concepts have been combined to increase the cyclic fatigue resistance of nickel-titanium (NiTi) instruments. The aim of this study was to compare the cyclic fatigue resistance of new M-Wire reciprocating WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) and Reciproc (VDW GmbH, Munich, Germany) files at 2 levels.

Methods: Sixty Reciproc and 60 WaveOne new files were fixed to a specifically designed device and tested in tempered steel canals with a 3-mm radius and a 60° angle of curvature.

Regional variations of µTBS of light- and chemically cured resin composite restorations in clinically relevant situations.

Purpose: To test whether the distance to the mass center of a buildup made of visible-light- or chemically curing composite resin bonded to dentin and cured in one increment has an influence on µTBS.

Materials And Methods: In the experimental groups, one-increment visible-light (Z250) or chemically-cured (TiCore) composite-resins buildups were bonded to flattened bovine dentin surfaces. In the control groups, the same materials were bonded as separate buildups on circumscribed areas to minimize the effect of shearing polymerization contraction.

Frequently asked questions in composite restorative dentistry.

Unlabelled: With an increasing number of dental practitioners using composite resins as the restorative material of choice, knowledge of terminology, handling properties and restorative techniques are important.

Clinical Relevance: This paper addresses many of the questions raised by participants at lectures and courses given by the authors across Europe.

Microtensile bond strength distributions of three composite materials with different polymerization shrinkages bonded to dentin.

Purpose: To assess the detrimental effects that polymerization contraction causes on the interfacial microtensile bond strength (μTBS) to dentin of three light-curing resin composites: two conventional bis-GMA-based composite resins (Filtek Z250, TPH Spectrum) and a low shrinkage material (Filtek Silorane [SIL]).

Materials And Methods: Flat surfaces of labial dentin were made in 46 bovine teeth and restored in single (group A) or in three separate (group B) one-increment visible-light cured resin composite blocks, with similar locations among teeth. After 24 h, restored teeth were sectioned perpendicular to interfaces, producing rectangular compound specimens (385 specimens were produced in group A, and 132 in group B), and submitted to tension (crosshead speed 1mm/min) until failure.

Effects of polymerization contraction on interface's microTBS of luting material and dentin.

Polymerization contraction of composite resin luting materials is known to produce high stresses in the interfaces being cemented that are described as perpendicular to them. This study describes the effect of shearing strains of curing luting materials on microtensile bond strength (microTBS) of interfaces. A flat surface of labial dentin of bovine incisors was exposed and teeth randomly assigned to A (n = 12) or B (n = 6) groups.

Relationship between postendodontic pain, tooth diagnostic factors, and apical patency.

This study compares the incidence, degree, and length of postoperative pain in 300 endodontically treated teeth, with and without apical patency, in relation to some diagnostic factors (vitality, presence of preoperative pain, group, and mandible of treated tooth). Of the questionnaires received back, apical patency was maintained during shaping procedures with a #10 K-file in one group (n = 115) and not in the other (n = 121). There was significantly less postendodontic pain when apical patency was maintained in nonvital teeth.

Microtensile bond strength of self-adhesive luting cements to ceramic.

Purpose: To test the null hypothesis that three self-adhesive luting materials had the same microtensile bond strength when used to lute ceramic IPS Empress II disks to the dentin of perfused teeth.

Materials And Methods: Occlusal enamel and the roots of 9 human third molars were removed and crown segments connected to a perfusion system (30 cm H2O). Nine ceramic disks (IPS Empress II) were prepared, conditioned with 5% HF (20 s), rinsed with water, and air dried.

Effects of etching time of primary dentin on interface morphology and microtensile bond strength.

Objectives: To determine the influence of different etching times (5, 15 or 30 s) on the morphology and micro-tensile bond strength (muTBS) of primary dentin.

Methods: For muTBS study, nine primary molars were randomly distributed in three experimental groups. Three Class I cavities per tooth were drilled and etched (37% orthophosphoric acid gel for 5, 15 or 30 s).

Method to compare mu-tensile bond strength of a self-etching adhesive and mu-cohesive strength of adjacent dentin.

Unlabelled: Laboratory results from tensile or micro-tensile testing of adhesive/restorative systems need a gold standard to make their interpretation possible. This can be done by comparing the mu-tensile bond strength (muTBS) of the tested adhesive(s) with the mu-tensile cohesive strength (muTCS) of the adjacent dentin, which is meant to be replaced by the restoration.

Objectives: To test immediate muTBS of an adhesive/restorative system versus muTCS of the dentin adjacent to the bonded interface, in perfused specimens.

Conversion from cyclosporin A to tacrolimus as a non-surgical alternative to reduce gingival enlargement: a preliminary case series.

Background: Gingival enlargement (GE) is a frequent side effect that occurs in organ transplant recipients (OTR) after the administration of cyclosporin A (CsA). The availability of new drugs used to suppress graft rejection in OTR offers an opportunity to manage GE non-surgically. This preliminary case series aimed to analyze the effect of CsA withdrawal and its substitution by another immunosuppressant in OTR with severe GE.

Inverse relationship between tensile bond strength and dimensions of bonded area.

It is a known fact that there is a relationship between magnitude of bonded area and laboratory tensile test results. This relationship has been described for a range of areas between 1 and 10 mm(2), in extracted, nonperfused teeth. The aim of this study is to test this relationship in perfused teeth, with bonded areas ranging from 0.