In vitro wear behavior of restorative resin composites against bovine enamel.

The purpose of this study was to clarify the effects of fabrication method of restorative resin-based composites on its wear using enamel as antagonist teeth. Wear evaluation was performed via two-body wear test using hemispherical samples of restorative resin-based composite (abrader specimen) fabricated through direct restoration method, indirect restoration method, and CAD/CAM, and bovine enamel (substrate specimen). As a result, there was a difference in wear volume between resin-based composite and bovine enamel depending on the fabrication method.

A case of desmoplakin mutation and delayed arrhythmogenic right ventricular cardiomyopathy/dysplasia after atrial septal defect closure.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a slow-developing cardiomyopathy characterized by ventricular arrhythmias and fibrofatty replacement of the right ventricular (RV) myocardium. Its clinical diagnosis is challenging because of its variable clinical presentation and low genetic penetrance. We describe the case of a 67-year-old man who was diagnosed as having ARVC/D with a desmoplakin mutation that appeared after occlusion of an atrial septal defect (ASD).

Corrosion behavior of titanium in response to sulfides produced by Porphyromonas gingivalis.

Objective: To investigate the effects of sulfides produced by Porphyromonas gingivalis (P. gingivalis) on the corrosion behavior of titanium.

Methods: Commercially pure titanium disks were mirror-polished and immersed in culture medium (BHI), spent medium after culturing P.

Effects of calcium hydroxide reagent on the bond strength of resin cements to root dentin and the retention force of FRC posts.

The aim of this study was to determine the effects of calcium hydroxide (Ca(OH)) treatment on bond strength of resin cements to root dentin and retention force of fiber-reinforced composite (FRC) posts. Bovine root dentin was endodontically prepared and treated with Ca(OH) for 7 days. Root dentin for bond strength test was adhered to resin-composite with resin cements.

Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber.

This study evaluated the microtensile bond strength (TBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (HO) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% HO-containing titanium dioxide (TiO) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2).

Participation of Patient Community Members in Communication Classes for Dental Students at Tokyo Dental College.

In 2009, the Ministry of Education, Culture, Sports, Science and Technology launched its "Program for Promoting University Education and Student Support, Theme A: Program for Promoting University Education Reform". The ministry's stated aims were to 1) enhance student training centered on the needs of the individual patient; 2) improve their ability to make comprehensive diagnosis and treatment plans; and 3) instill high ethical standards and good communication skills. One of the main pillars of this project was to establish an educational organization aimed at encouraging public participation, the "Patient Community".

Influence of sulfide concentration on the corrosion behavior of titanium in a simulated oral environment.

This study assessed the corrosion behavior of titanium in response to sulfide by determining the effects of sulfide concentration and pH over immersion period. Corrosion was evaluated through changes in color, glossiness, surface characterization, and titanium release. Sulfide solutions were prepared in 3 different concentrations with Na2S, each in pH unadjusted (sulfide-alkaline) and pH adjusted to 7.

Development of a Drilling Simulator for Dental Implant Surgery.

The aim of this study was to develop and evaluate a dental implant surgery simulator that allows learners to experience the drilling forces necessary to perform an osteotomy in the posterior mandibular bone. The simulator contains a force-sensing device that receives input and counteracts this force, which is felt as resistance by the user. The device consists of an actuator, a load cell, and a control unit.

The influence of colored zirconia on the optical properties of all-ceramic restorations.

This study investigated the effects of different colored tetragonal zirconia polycrystal (TZP) core on the optical properties of TZP framework restorations. Three various colors of TZP discs (Katana Zirconia) 14 mm in diameter and 0.5 mm thickness were layered with 2 shades of veneering ceramics (shade A1 and A4: Cerabian ZR).

Effect of intermediate ceramics and firing temperature on bond strength between tetragonal zirconia polycrystal and veneering ceramics.

The purpose of the present study was to investigate the influence of the intermediate ceramics and firing temperature on bond strength between tetragonal zirconia polycrystal (TZP) and its intermediate ceramics. Two types of intermediate ceramics, defined as a ceramics placed between the TZP and its veneering ceramics, were used; one including high-strength lithium-disilicate (EP) or feldspathic liner porcelain (SB). The firing temperature of the intermediate ceramics was set at 930°C, 945°C or 960°C.

Effect of adhesive system on retention in posts comprising fiber post and core resin.

The purpose of this study was to compare the retention of fiber-reinforced composite (FRC) posts luted with either conventional or self-adhesive resin cement. The FRC posts and core resin were built up in bovine teeth. The posts were luted with standard etch-andrinse cement, self-etch cement, or one of two self-adhesive cements.

Discoloration of titanium alloy in acidic saline solutions with peroxide.

The objective of this study was to compare corrosion behavior in several titanium alloys with immersion in acidulated saline solutions containing hydrogen peroxide. Seven types of titanium alloy were immersed in saline solutions with varying levels of pH and hydrogen peroxide content, and resulting differences in color and release of metallic elements determined in each alloy. Some alloys were characterized using Auger electron spectroscopy.

Establishment and current status of patient community at Tokyo Dental College.

The "Dental students training to address the needs of each individual patient: enhancement of ability to make a comprehensive diagnosis and treatment plans with high ethical standards and good communication skills", project launched at Tokyo Dental College was adopted by the Ministry of Education, Culture, Sports, Science and Technology as part of its "Program for Promoting University Education and Student Support, Theme A: Program for Promoting University Education Reform" in 2009. One of the main goals of this subject is "the establishment of Patient Community". Patient Community members allowed students to gain a more realistic experience of clinical practice than simulated patients.

Flexural properties of three kinds of experimental fiber-reinforced composite posts.

The aim of this study was to estimate the flexural properties of three kinds of experimental fiber-reinforced composite (FRC) posts and to evaluate their potential use as posts. Experimental FRC posts were fabricated with glass, aramid, and UHMWP fibers. Commercial FRC posts were used for comparison.

Development and status of e-Learning program at Tokyo Dental College.

This article reports the development and current status of an e-Learning system (hereafter, referred to as "ELS") at Tokyo Dental College. The ELS was developed to promote self-study. In order to achieve this, all new students were encouraged to use a notebook PC, and an intramural IT environment providing full, wireless LAN Web access was established.

Effect of chromium content on mechanical properties of casting Ti-Cr alloys.

The mechanical properties of a series of binary Ti-Cr alloys were investigated. Chromium content ranged from 5 to 20 mass%. Dumbbell- and disk-shaped specimens of each alloy were obtained by casting for mechanical testing and microstructural observation.

Durability of fiber-post and resin core build-up systems.

The aim of this study was to evaluate the durability of unidirectional and bidirectional fiber-reinforced post systems under static and cyclic loading. Three prefabricated fiber posts with one of two core composite resins each or a post resin were used. Each specimen was subjected to a three-point bending test after cyclic loading (1000 times) by 0.

Mechanical properties of roots combined with prefabricated fiber post.

This study examined the mechanical properties of roots combined with prefabricated fiber post. Three types of specimens were evaluated: (1) prefabricated fiber post alone (FP); (2) core composite resin with FP (CFP); and (3) root with CFP (RCFP). The volume fractions of the prefabricated fiber post in the core composite resin (FP/CFP ratio) were set to 0, 0.

Influence of peroxide treatment on bovine enamel surface--cross-sectional analysis.

Carbamide peroxide and hydrogen peroxide are used as the main agents in vital tooth bleaching. In this study, the influence of peroxide treatment on cross-sectional morphology and mechanical property was investigated. A 3 x 5-mm window of enamel on the labial surface of a bovine tooth was exposed to immersion in 10% or 30% carbamide peroxide or hydrogen peroxide for 30 or 180 min.

Corrosion mechanism of Ti-Cr alloys in solution containing fluoride.

Objective: The objective of this study was to clarify the influence of chromium content on surface reaction of Ti-Cr alloys in an acidic fluoride-containing saline solution.

Methods: Four Ti-Cr alloys containing 5, 10, 15 or 20 mass% chromium were characterized in terms of dissolution of metals in an acidic fluoride-containing saline solution and surface structure by X-ray photoelectron spectroscopy and Auger electron spectroscopy.

Results: Total amount of metals dissolved from each alloy decreased with increase in chromium content.

Development of computer-based OSCE re-examination system for minimizing inter-examiner discrepancy.

The validity of objective structured clinical examination (OSCE) in evaluating clinical skills has been confirmed in a number of studies. However, inter-examiner reliability has been noted as a concern by many educators. To minimize discrepancy between examiners, in application of the OSCE, we have developed an OSCE attitude and skill test re-examination system.

Suppression of fluoride-induced corrosion of titanium by albumin in oral modified environment.

Although fluoride induces corrosion in titanium in an oral environment, the influence of protein on this corrosion remains to be clarified. The objective of this study was to investigate suppression of fluoride-induced corrosion of titanium where albumin was either present in a solution or where albumin was preadsorbed on titanium. Titanium dissolution in titanium specimens and surface characterization of each specimen were determined.

Discoloration and dissolution of titanium and titanium alloys with immersion in peroxide- or fluoride-containing solutions.

This study compared differences in discoloration and dissolution in several titanium alloys with immersion in peroxide- or fluoride-containing solution. Commercially pure titanium (CP-Ti) and six titanium-based alloys were used: Ti-0.15Pd, Ti-6Al-4V, Ti-7Nb-6Al, Ti-55Ni, Ti-10Cu, and Ti-20Cr.