Changes in the Properties of Different Zones in Multilayered Translucent Zirconia Used in Monolithic Restorations During Aging Process.

This study assessed the changes in the mechanical and surface properties of the transition zone in multilayered translucent monolithic zirconia subjected to long-term hydrothermal aging. A total of 360 disk-shaped specimens (diameter: 15.0 mm; thickness: 1.

Biomineralization reaction from nanosized calcium silicate: A new method for reducing dentin hypersensitivity.

Background/purpose: This study assessed the ability of experimental materials consisting of dicalcium silicate (DCS) and tricalcium silicate (TCS) with nanosized particles to form intratubular crystals under phosphate-buffered saline (PBS) and the effect on dentin permeability reduction.

Materials And Methods: By isolating the cervical part of the extracted premolars, 195 specimens were obtained. Two experimental materials (DCS/TCS and TCS) were applied to the dentin surface by brushing and stored in PBS (n = 65).

Effect of dentin surface conditions and curing mode of resin cement on the dentin bond strength.

This study investigates the effects of dentin's drying time, roughness, and curing modes of resin cement on bond strength. Forty human teeth were divided into eight groups based on three experimental factors: dentin's roughness by 240-or 600-grit SiC paper (coarse or fine), dentin wetness with air-drying time (5-s or 10-s), and Single Bond Universal adhesive's curing mode by co-curing with RelyX Ultimate cement or light-curing separately (co-curing or light-curing). The micro-tensile bond strength of fifteen resin-dentin stikcs per groups was measured.

Shear bond strength of dual-cured resin cements on zirconia: The light-blocking effect of a zirconia crown.

Abstract Background/purpose: The presence of restorative material between resin cement and the light-curing unit can reduce light transmission. This study aimed to evaluate the effect of the light-blocking effect of zirconia crown on shear bond strength (SBS) between three dual-cured resin cements and the zirconia surface.

Materials And Methods: Sixty zirconia specimens were prepared and divided into three groups according to the type of resin cement [RXU (RelyX Ultimate); SC2 (SmartCem2); MEC (Maxcem Elite Chroma)].

Lipopolysaccharide penetration analysis of two different resin cement systems to dentin and ceramic surface.

Background/purpose: One of the challenges in adhesive ceramic restorations is deterioration of tooth-cement-ceramic interfaces. This study was to quantitatively investigate lipopolysaccharide (LPS) penetration through adhesive ceramic restorations.

Materials And Methods: Standardized holes were formed on ceramic (IPS Empress CAD, Ivoclar Vivadent) and human dentin discs.

Intratubular crystal formation in the exposed dentin from nano-sized calcium silicate for dentin hypersensitivity treatment.

The aim of this study is to evaluate intratubular crystal formation from the experimental material consisting of dicalcium silicate (CS) and tricalcium silicate (CS) with nano-scaled particle size. A total of twenty-four specimens were made by isolating 8 mm of the cervical part centered at the cementoenamel junction of extracted premolars. Twelve specimens were not treated and considered as control.

Effects of a blended design of closed-book and open-book examinations on dental students' anxiety and performance.

Background: While closed-book examinations (CBEs) have traditionally been implemented in dental education, open-book examinations (OBEs) are being introduced for the purpose of acquiring higher levels of knowledge and promoting long-term memory. This study examines whether it is effective to use a blended assessment of CBEs and OBEs for dental students to reduce test anxiety and enhance academic performance.

Methods: Using a quasi-experimental research method, a blended assessment that combined CBEs in class and OBEs online was designed for a dental course.

Effects of virtual body-representation on motor skill learning.

Motor learning is often hindered or facilitated by visual information from one's body and its movement. However, it is unclear whether visual representation of the body itself facilitates motor learning. Thus, we tested the effects of virtual body-representation on motor learning through a virtual reality rotary pursuit task.

In vivo real-time temperature measurement on the surface of intact and gold-restored teeth during consumption of hot and cold drinks.

This study aimed to measure real-time temperature changes in gold-restored teeth compared with intact teeth during the intake of hot and cold drinks. Sixteen molars, including eight natural intact teeth and eight restored teeth with gold inlays, were selected from the participants. Custom-made thermocouple sensors were attached to the coronal third of the buccal surface of teeth.

Effect of cyclic thermal stress on the fatigue life of teeth restored with gold inlay.

This study aimed to evaluate the stress distribution that results from temperature changes in teeth restored with gold inlay and to predict the fatigue life of the teeth. A thermal load regimen for finite element analysis (FEA) was established in an in vivo experiment, in which participants with gold inlays drank hot and cold water. An extracted human maxillary molar was converted into a 3D FEA model.

Influence of different inlay configurations and distance from the adjacent tooth on the accuracy of an intraoral scan.

Statement Of Problem: Clinical guidelines for obtaining accurate scan data during the intraoral scanning of inlay cavities with various configurations and interproximal distances are lacking.

Purpose: The purpose of this in vitro study was to evaluate the effect of interproximal distance and cavity type on the accuracy of digital scans for inlay cavities, including proximal cavities.

Material And Methods: Four artificial teeth with 4 types of inlay cavities designed based on the buccolingual width and gingival level of the proximal box were installed in a mannequin at distances of 0.

Association between longitudinal tooth fractures and visual detection methods in diagnosis.

Objectives: This study investigated the distribution of longitudinal tooth fractures (LTFs) according to the patient's age and analyzed the association between visual detection methods and the types of LTFs.

Methods: Patients with symptomatic teeth with LTFs were examined at the department of conservative dentistry in a dental hospital from September 1, 2009 to March 31, 2014. Naked eye examination, staining with a dye, operating microscopy, transillunimation, and periapical radiography were used to identify the fracture lines.

Did Clinical Reasoning and Knowledge Questions During Team-Based Learning Enhance Dental Students' Performance in Esthetic Dentistry?

The aim of this study was to assess whether clinical reasoning and factual knowledge questions used in team-based learning (TBL) enhanced dental students' performance in esthetic dentistry. Ninety-seven third-year dental students enrolled in esthetic dentistry in a dental school in Korea in 2018 were assigned to 16 teams consisting of five or six students each. A four-step TBL sequence (pre-study, readiness assurance test, appeal/feedback, and final test) was designed to examine how clinical reasoning and knowledge questions affected academically high- and low-achieving students.

Catechol-thiol-based dental adhesive inspired by underwater mussel adhesion.

The critical problem associated with the underwater mussel adhesive catechol-based 3,4-dihydroxy-L-phenylalanine (DOPA) is its sensitivity to oxidation. To overcome this problem, mussels underwent etching in the presence of acidic pH conditions (<3.0), and thiol chemistry was used to control the propensity of DOPA for oxidation.

Effects of Printing Parameters on the Fit of Implant-Supported 3D Printing Resin Prosthetics.

The purpose of the study was to investigate the influence of 3D printing parameters on fit and internal gap of 3D printed resin dental prosthesis. The dental model was simulated and fabricated for three-unit prostheses with two implants. One hundred prostheses were 3D printed with two-layer thicknesses for five build orientations using a resin (NextDent C&B; 3D systems, Soesterberg, The Netherlands) and ten prostheses were manufactured with a milling resin as control.

Biocompatibility and Mineralization Activity of Three Calcium Silicate-Based Root Canal Sealers Compared to Conventional Resin-Based Sealer in Human Dental Pulp Stem Cells.

The purpose of this study was to compare the cytotoxic effects and mineralization activity of three calcium silicate-based root canal sealers to those of a conventional resin-based sealer. Experiments were performed using human dental pulp stem cells grown in a monolayer culture. The root canal sealers tested in this study were EndoSequence BC Sealer (Brasseler), BioRoot RCS (Septodont), Endoseal MTA (Maruchi), and AH Plus (Dentsply DeTrey).

Transparent wearable three-dimensional touch by self-generated multiscale structure.

Pressure-sensitive touch panels can measure pressure and location (3D) information simultaneously and provide an intuitive and natural method for expressing one's intention with a higher level of controllability and interactivity. However, they have been generally realized by a simple combination of pressure and location sensor or a stylus-based interface, which limit their implementation in a wide spectrum of applications. Here, we report a first demonstration (to our knowledge) of a transparent and flexible 3D touch which can sense the 3D information in a single device with the assistance of functionally designed self-generated multiscale structures.

Do Dental Students' Personality Types and Group Dynamics Affect Their Performance in Problem-Based Learning?

The aim of this study was to determine whether the personality types of dental students and their group dynamics were linked to their problem-based learning (PBL) performance. The Myers-Briggs Type Indicator (MBTI) instrument was used with 263 dental students enrolled in Seoul National University School of Dentistry from 2011 to 2013; the students had participated in PBL in their first year. A four-session PBL setting was designed to analyze how individual personality types and the diversity of their small groups were associated with PBL performance.

How light attenuation and filler content affect the microhardness and polymerization shrinkage and translucency of bulk-fill composites?

Objectives: The purpose of this study was to investigate the microhardness, polymerization shrinkage, and translucency of bulk-fill composites (BFCs) which have different light attenuation properties and filler contents.

Materials And Methods: Five BFCs [Filtek Bulk Fill (FB), SureFil SDR (SS), Venus Bulk Fill (VB), SonicFill (SF), and Tetric N-Ceram Bulk Fill (TB)] and two resin-based composites (RBCs) [Tetric N-Ceram (TN) and Filtek Z350XT Flowable (ZF)] were chosen. Numbers of transmitted photons, refractive index, microhardness at different thicknesses, polymerization shrinkage, and translucency parameter (TP) were evaluated.

Dentin wear after simulated toothbrushing with water, a liquid dentifrice or a standard toothpaste.

Purpose: To investigate the influence of dentifrices with and without abrasives on the wear and surface topography of human dentin following simulated toothbrushing in vitro.

Methods: 24 dentin specimens were prepared and randomly allocated to a liquid dentifrice (Garglin Gum-Guard), conventional dentifrice (333 Clinic Total Care), and control (distilled water) groups. Specimens were subjected to simulated toothbrushing of 50,000 repeated strokes under a 150 g-load.