Daniel Chi Ngai Chan

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OBJECTIVE The purpose of this study was to examine the effect of solvent concentration on the degree of conversion of a model photo-activated resin formulation when placed as a thin film in ambient air. METHODS A photo-activated co-monomer mixture (ethoxylated bis-GMA/TEGDMA) (Bisco Inc.) was diluted into six concentrations (from 1.0 to 13.0M) with either(More)
The aim of this study was to evaluate the features of dentinal tubules occlusion following application of three commercially available desensitizing agents: potassium oxalate-based / Oxa-Gel (OX), HEMA and glutaraldehyde-based / Gluma Desensitizer (GD) and acidulated phosphate fluoride-based / Nupro Gel (AF). Buccal cervical areas of twenty-four extracted(More)
Consistently choosing an accurate shade match is far more difficult than it appears. Recently, several electronic shade-matching devices have been marketed. One device is an intraoral spectrophotometer, Easyshade. The current study compared the accuracy and consistency of the Easyshade (ES) device to three clinicians experienced in tooth whitening trials(More)
OBJECTIVES This study evaluated the dentine bond strength (BS) and the antibacterial activity (AA) of six adhesives against strict anaerobic and facultative bacteria. METHODS Three adhesives containing antibacterial components (Gluma 2Bond (glutaraldehyde)/G2B, Clearfil SE Protect (MDPB)/CSP and Peak Universal Bond (PUB)/chlorhexidine) and the same(More)
The retentive and morphologic changes of overdenture attachments were evaluated independently after repeated insertion and sinusoidal loading on implant abutments. Stud and magnetic attachments were embedded in overdenture housing (n = 5). The overdentures were subjected to either repeated insertion and removal for 5,400 cycles or sinusoidal cyclic loading(More)
Every day in the United States, complete caries removal in vital, asymptomatic teeth with deep carious lesions ends in unavoidable exposure of the pulp. As a result, the complexity and cost of treatment increases dramatically and many patients are left with extraction as their only viable option. This review appraises evidence which supports alternative(More)
The objective of this study has been to characterize sialolith, a calcium phosphate deposit that develops in the human oral cavity, by high-resolution field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The morphological and chemical data obtained helped in the determination of their formation mechanism in salivary(More)
STATEMENT OF PROBLEM The ceramic composition and microstructure surface of all-ceramic restorations are important components of an effective bonding substrate. Both hydrofluoric acid etching and airborne aluminum oxide particle abrasion produce irregular surfaces necessary for micromechanical bonding. Although surface treatments of feldspathic and leucite(More)
This placebo-controlled, double-blind randomized clinical trial compared five 10% carbamide peroxide tooth whitening formulations. Three products contained varying concentrations of potassium nitrate as desensitizers. One contained no desensitizers and one was a placebo. During the two weeks of active bleaching, participants used a daily diary to record the(More)
The purpose of this study was to determine the reliability of the data acquisition and modeling process of laser and white light scanners by evaluating the reproducibility of digitized simulated crowns with different convergences. A secondary purpose was to analyze the influence of die preparation by testing this hypothesis with a set of dies without(More)