Publications by authors named "Tak W Chow"

Objective: To prospectively evaluate patient-reported outcome measures (PROMs) and treatment outcomes of mandibular two-implant retained overdentures (IOD) in an edentulous geriatric cohort with history of deficient complete dentures (CD).

Materials And Methods: A total of 103 patients with deficient CD received new optimal CD. After a period of 3 months, 80 of the patients voluntarily received IOD.

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Aim: The aim of the present study was to compare the accuracy of radiographic measurements for dental implants planning using cone-beam computed tomography (CBCT) and helical computed tomography (HCT).

Methods: Six pig ribs were wrapped by putty impression material, with radiographic markers placed. Two CBCT and an HCT were taken following the standard protocols.

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Objective: The purpose of this prospective clinical study was to determine whether reduced bone mineral density (BMD) is correlated with a higher risk for dental implant therapy in an elderly patient population.

Material And Methods: Seventy-nine patients recruited at the Prince Philip Dental Hospital were provided with 2-implant-supported mandibular overdentures. Skeletal BMD was recorded before the implant therapy.

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Purpose: Ceramics are widely used as indirect restorative materials in dentistry because of their high biocompatibility and pleasing aesthetics. The objective is to review the state of the arts of CAD/CAM all-ceramic biomaterials.

Study Selection: CAD/CAM all-ceramic biomaterials are highlighted and a subsequent literature search was conducted for the relevant subjects using PubMed followed by manual search.

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Purpose: The study evaluated the diagnostic performance of computed tomography (CT) bone density measurements (in Hounsfield units [HU]) in assessing the osteoporotic status of edentulous subjects (21 men, 40 women) scheduled to receive mandibular implant-supported overdentures.

Materials And Methods: Density (in HU) of 61 left and 61 right mandibular canine sites was measured. Each subject was also subject to body bone mineral density measurements (dual-energy x-ray absorptiometry).

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Purpose: To study the changes in treatment outcomes of complete dentures and magnet-retained, implant-supported overdentures in a group of elderly patients.

Materials And Methods: In this nonrandomized trial, 43 edentulous patients (14 men and 29 women) were fitted with complete dentures followed by implant-supported mandibular overdenture in a sequential model. Treatment outcomes used for analysis included objective assessment of denture quality (Woelfel's index), patient satisfaction, nutritional status, body mass index (BMI), and serum albumin level.

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Purpose: Osteoporotic patients require particular attention during implant placement, and insertion torque (IT) has been established as a simple and noninvasive method to assess local bone quality and primary implant stability. This study aimed to test the hypothesis that IT was not significantly correlated with bone density, as assessed with computed tomography, in a group of osteopenic and osteoporotic patients. In addition, the hypothesis that IT was not significantly correlated with implant length was tested.

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Purpose: The effect of surface treatment using tribochemical silica coating/silane coupling on the shear bond strengths of (1) a glass-infiltrated, zirconia-reinforced alumina (In-Ceram Zirconia) and (2) a yttria-stabilized zirconia ceramic (YZ Zirconia) to human dentin was studied.

Materials And Methods: Twelve specimens of each ceramic were randomly assigned to one of three surface treatments: (1) no surface treatment (control group); (2) a chairside tribochemical silica coating/silane coupling system (CoJet group); and (3) a laboratory tribochemical silica coating/silane coupling system (Rocatac group). The mode of failure of each specimen was determined under magnification.

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Statement Of Problem: The fracture of maxillary complete dentures has been reported as the most common prosthesis failure.

Purpose: The purpose of this study was to evaluate strain distribution in dentures during application of occlusal load with 3-dimensional (3-D) finite element analysis (FEA).

Material And Methods: A maxillary complete denture was converted into a 3-D numerical model by an advanced topometric sensor digitizer (ATOS).

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The adhesive property of a dual-cure, self-adhesive universal resin luting agent (Rely X Unicem, 3M ESPE) between nickel-chromium (Ni-Cr) and human dentine was compared with three conventional resin luting agents (Calibra, Dentsply; Panavia-F, Kuraray; All-bond 2 C & B cement, Bisco). Ten Ni-Cr rods were bonded to human dentine with each of the four luting agents, and were subjected to shear bond test. Results showed that there was no significant difference in shear bond strengths among the luting agents.

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Purpose: This study was undertaken to investigate the chemical solubility and flexural strengths of 3 zirconia-based dental ceramics: In-Ceram Zirconia (IZ), In-Ceram 2000 YZ CUBES (YZ Zirconia) (Vita Zahnfabrik), and Cercon (Dentsply). A pressable lithium disilicate-reinforced glass ceramic (IPS Empress 2, Ivoclar Vivadent) was used as a control.

Materials And Methods: Ten block specimens (12 x 6 x 4 mm) of each ceramic material were prepared for chemical solubility testing.

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Localized severe chronic periodontitis is often seen in middle-aged patients, particularly when plaque control for malaligned teeth is not satisfactory. While orthodontic treatment can realign such teeth with reduced periodontal support, esthetics may be compromised by gingival recession due to preexisting bone loss and resolution of inflammation after periodontal treatment. This clinical report describes how a malaligned maxillary lateral incisor with severe periodontitis was replaced by an immediately placed implant and implant-supported crown with a good esthetic outcome.

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Statement Of Problem: Although ceramic veneers have been proven to be clinically successful in longevity studies, there is little information on the contrast ratios and masking ability of the available ceramic systems because dental laboratory technology and expensive experimental equipment are required for the investigation. Moreover, the complexity in understanding how to evaluate translucent ceramic materials may also explain why information in this area is limited.

Purpose: The purpose of this study was to determine the contrast ratios and masking abilities of 3 types of all-ceramic veneers by measuring their luminance and color difference over white and black backgrounds.

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This study aimed to compare the retentive forces of cast cobalt-chromium (Co-Cr) and commercially pure titanium (cpTi) clasps. A clasp assembly comprising a pair of symmetrical clasps was made to fit the opposite halves of a hardened stainless-steel sphere. This twin clasp was designed to counterbalance the tipping forces when the clasp assembly was drawn from the sphere.

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Purpose: To investigate 6 dental statuses as risk factors for malnutrition in geriatric patients admitted to a convalescent and rehabilitation hospital.

Materials And Methods: One hundred twenty (59 men and 61 women) geriatric patients admitted to a convalescent and rehabilitation hospital were recruited. Three biochemical and hematologic parameters (albumin, hemoglobin, and lymphocyte count) were used for analysis.

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The study was aimed at comparing the efficacy of disinfection of root canals with periapical radiolucencies when treated with either antibiotics/steroid medicaments (Ledermix or Septomixine) or a calcium hydroxide paste (Calasept). Microbiological samples were taken before and after two-visit endodontic treatment from 88 canals with apical periodontitis. All of the canals but one (87 of 88) had cultivable growth before treatment.

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Purpose: The aim of this study was to determine the original water content of a supplied acrylic resin powder and a monomer and of dry heat-processed acrylic bars. The effect of the original water content of acrylic resin on processing shrinkage was also investigated.

Materials And Methods: Ten bar specimens were fabricated using dried and as-supplied (control) acrylic resins.

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This study was aimed at comparing the cultivable microorganisms in canals with periapical radiolucencies with exposed and unexposed pulp space. Microbiological samples were taken and analyzed from 45 canals with exposed pulp space, and 43 canals with unexposed pulp space. The canal contents were analyzed by aerobic/anaerobic culture, and conventional identification techniques.

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Statement Of Problem: Discoloration of provisional prosthodontic materials may result in patient dissatisfaction and additional expense for replacement.

Purpose: The purpose of this study was to determine the color stability of 5 provisional prosthodontic materials before and after immersion in distilled water or coffee for 20 days or exposure to ultraviolet (UV) light for 24 hours.

Material And Methods: A total of 105 disc-shaped specimens (20+/-0.

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Tooth tissue loss from bruxism has been demonstrated to be associated with various dental problems such as tooth sensitivity, excessive reduction of clinical crown height, and possible changes of occlusal relationship. A literature search revealed a number of treatment modalities, with an emphasis on prevention and rehabilitation with adhesive techniques. Rehabilitating a patient with bruxism-associated tooth tissue loss to an acceptable standard of oral health is clinically demanding and requires careful diagnosis and proper treatment planning.

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Degenerative neurologic disorders such as Parkinson's disease are becoming more prevalent as life expectancy is improved. Although the use of an implant-supported overdenture is an acceptable treatment modality, the clinician should recognize the indications and maintenance requirements of different attachment systems for individual patients. The use of a magnetic attachment system in an implant-supported mandibular overdenture for an edentulous patient with Parkinson's disease is presented.

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Purpose: The purposes of this study were to: (1) investigate the correlation between the color difference of bilayer porcelain veneers over white and black backgrounds (deltaE1) and their opacity (contrast ratios); (2) determine whether there is a recommendable threshold contrast ratio above which the color difference is clinically acceptable (when deltaE < or = 5); and (3) compare the ability of porcelain veneers to mask a color change from white to black backgrounds (deltaE1) and their ability to mask a color change from white to clinically discolored teeth (deltaE2).

Materials And Methods: Forty-four maxillary anterior teeth of eight patients with severe tetracycline discoloration were prepared for bilayer porcelain veneers in shade A2 porcelain. The cores were 0.

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Different laboratory techniques are available for making porcelain veneers, and each has its own advantages and limitations. This article describes how high-density alumina core constructed with Computer Assisted Design/Computer Assisted Manufacture (CAD/CAM) technology can be successfully used for making porcelain veneers. Different clinical conditions are also presented to illustrate the use of these bi-layer veneers.

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The use of craniofacial implants to assist in retaining auricular prostheses often requires complex laboratory procedures, involving production of an accurate casting, fitting of a precious alloy bar, and the use of clips. A simplified method for the retention of an auricular prosthesis with a composite bar and magnets is described in this article.

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