Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Kwok-Hung Chung is active.

Publication


Featured researches published by Kwok-Hung Chung.


Clinical Implant Dentistry and Related Research | 2015

A Novel Dental Implant Guided Surgery Based on Integration of Surgical Template and Augmented Reality

Yen-Kun Lin; Hong-Tzong Yau; I‐Chung Wang; Cheng Zheng; Kwok-Hung Chung

BACKGROUNDnStereoscopic visualization concept combined with head-mounted displays may increase the accuracy of computer-aided implant surgery.nnnPURPOSEnThe aim of this study was to develop an augmented reality-based dental implant placement system and evaluate the accuracy of the virtually planned versus the actual prepared implant site created in vitro.nnnMATERIALS AND METHODSnFour fully edentulous mandibular and four partially edentulous maxillary duplicated casts were used. Six implants were planned in the mandibular and four in the maxillary casts. A total of 40 osteotomy sites were prepared in the casts using stereolithographic template integrated with augmented reality-based surgical simulation. During the surgery, the dentist could be guided accurately through a head-mounted display by superimposing the virtual auxiliary line and the drill stop. The deviation between planned and prepared positions of the implants was measured via postoperative computer tomography generated scan images.nnnRESULTSnMean and standard deviation of the discrepancy between planned and prepared sites at the entry point, apex, angle, depth, and lateral locations were 0.50u2009±u20090.33u2009mm, 0.96u2009±u20090.36u2009mm, 2.70u2009±u20091.55°, 0.33u2009±u20090.27u2009mm, and 0.86u2009±u20090.34u2009mm, respectively, for the fully edentulous mandible, and 0.46u2009±u20090.20u2009mm, 1.23u2009±u20090.42u2009mm, 3.33u2009±u20091.42°, 0.48u2009±u20090.37u2009mm, and 1.1u2009±u20090.39u2009mm, respectively, for the partially edentulous maxilla. There was a statistically significant difference in the apical deviation between maxilla and mandible in this surgical simulation (pu2009<u2009.05).nnnCONCLUSIONSnDeviation of implant placement from planned position was significantly reduced by integrating surgical template and augmented reality technology.


Clinical Implant Dentistry and Related Research | 2014

Cementing an Implant Crown: A Novel Measurement System Using Computational Fluid Dynamics Approach

Chandur Wadhwani; Sabine Goodwin; Kwok-Hung Chung

BACKGROUNDnCementing restorations to implants is a widely used clinical procedure. Little is known about the dynamics of this process. Using a systems approach and advanced computing software modeling this can be investigated virtually. These models require validation against real-life models.nnnPURPOSEnThe study aims to consider the system effect of a crown, abutment, and cement flow under different conditions and comparing real physical models to virtual computer simulations.nnnMATERIALS AND METHODSnA physical model of implant abutments and crowns provided three groups according to abutment screw access modification (nu2009=u20099): open (OA), closed (CA), and internal vented (IVA) abutment groups. Crowns were cemented using standardized amounts and site application. Proportion of cement retained within the crown-abutment system was recorded and compared. Differences among groups were identified using analysis of variance (ANOVA) with Tukeys post hoc test (αu2009≤u20090.05). Three-dimensional multiphysics numerical stimulation software (STAR-CCM+, CD-adapco) with computational fluid dynamics (CFD) approach was applied to a virtual model system of a scanned abutment and crown system. Three-dimensional real-time model simulations of cement and air displacement were produced, evaluating cement application site, speed of crown seating, and abutment modifications.nnnRESULTSnStatistically significant differences in cement retained within the system (pu2009<u20090.01) were found among the IVAu2009>u2009OAu2009>u2009OCA abutment groups. The CFD virtual simulations followed this trend. Site application and speed of seating also affected cement extrusion and cement marginal infill. Fast crown seating and occlusal cement site application produced air incorporation at the margins.nnnCONCLUSIONSnThe CFD approach provides a convenient way to evaluate crown-cement-implant abutment systems with respect to cement flow. Preliminary evaluation indicates that the results achieved follow those of a physical actual cement-retained crown-implant abutment study.


Journal of Prosthetic Dentistry | 2016

Laboratory technique for coloring titanium abutments to improve esthetics

Chandur Wadhwani; Richard O’Brien; Mathew T. Kattadiyil; Kwok-Hung Chung

Titanium alloys are used for implant abutments onto which prostheses are attached. One major disadvantage of titanium abutments is their esthetics; the metallic gray color may show through the restorative material or through surrounding tissues. A laboratory technique using readily available household items is described that can alter the abutment color by anodization.


Journal of Prosthetic Dentistry | 2017

Effect of hydrothermal treatment on light transmission of translucent zirconias

Armand Putra; Kwok-Hung Chung; Brian D. Flinn; Tuesday Kuykendall; Cheng Zheng; Kosuke Harada; Ariel J. Raigrodski

Statement of problem. Studies of the light transmission of translucent zirconias after hydrothermal treatment are limited. Purpose. The purpose of this in vitro study was to evaluate the effect of hydrothermal treatment on the light transmission of translucent zirconias for monolithic restorations. Material and methods. Four commercially available zirconia products, BruxZir Anterior Solid Zirconia (BruxAnt, BA), Lava Plus High Translucency (LPHT), Katana Zirconia Super Translucent (KST), and Katana Zirconia Ultra Translucent (KUT) were assessed and 1 type of lithium disilicate, e.max Press LT (LDLT) was used as a control. Plate specimens, 20×20×1 mm (n=80) for the translucency assessment were sectioned from postsintered zirconia bulk materials and ground with a #400‐grit diamond wheel and coolant. The specimens were placed under hydrothermal conditions of 134°C at 0.2 MPa (n=5 per group at 0, 5, 50, and 100 hours). Percentage of total transmittance of light (Tt%) of each specimen was measured using a spectrophotometer with an integrating sphere. X‐ray diffraction analyses were used to measure tetragonal‐monoclinic phase transformation. Surfaces were examined by scanning electron microscopy and energy dispersive spectrometry. Data were analyzed using 2‐way ANOVA followed by the Tukey test (&agr;=.05). Results. The Tt% ranged from 6.5% to 28.3%. Group LDLT obtained significantly higher transmittance than other tested groups, whereas groups KST and KUT had significantly higher Tt% than groups BA and LPHT (P<.05). A statistically significant increase in the amount of monoclinic phase was revealed within all translucent zirconia groups (P<.05), and the increase in group LPHT was significantly higher than those of the other 3 translucent zirconias (P<.05). Minimal changes in the percentages of light transmittance were revealed after 100‐hour hydrothermal treatment for all tested translucent zirconias and a lithium disilicate glass‐ceramic control. Conclusions. Hydrothermal treatment had minimal effects on the translucency of translucent zirconias. The tetragonal‐monoclinic phase transformation rate of translucent zirconias was found to be low, except in group LPHT.


Clinical Implant Dentistry and Related Research | 2016

In‐Vitro Study of the Contamination Remaining on Used Healing Abutments after Cleaning and Sterilizing in Dental Practice

Chandur Wadhwani; Todd R. Schonnenbaum; Franco Audia; Kwok-Hung Chung

BACKGROUNDnReuse or recycle of dental implant healing abutments in clinical practice is common, primarily for economic rational.nnnPURPOSEnTo determine of this practice results in reuse of components that carry with them some degree of contamination between patients, even following thorough cleaning and sterilization.nnnMATERIALS AND METHODSnOne hundred healing abutments were collected from eight clinicians following patient use. The abutments were cleaned, sterilized, and then collected. The samples were treated with a protein specific stain (Phloxine B), and photographed.nnnRESULTSnNinety-nine percent of the abutments showed protein contamination at one or more sites following cleaning and sterilization.nnnCONCLUSIONnReuse of healing abutments between patients should be reevaluated in light of this data.


Journal of Prosthetic Dentistry | 2018

Colorizing titanium-6aluminum-4vanadium alloy using electrochemical anodization: Developing a color chart

Chandur Wadhwani; Marco Brindis; Mathew T. Kattadiyil; Richard O’Brien; Kwok-Hung Chung

Colorizing titanium alloys by electrochemical anodization is used in dentistry especially for identification purposes. Colorization is the result of distinct voltage applications to specific titanium alloys when placed in an electrolyte. Titanium and titanium alloys differ in their ability to be anodized. As titanium-6aluminum-4vanadium is commonly used as an abutment material, we have developed a specific color reference scale relating color to the voltage applied.


Acta Biomaterialia Odontologica Scandinavica | 2015

Antibacterial activity of gold-titanates on Gram-positive cariogenic bacteria

Trinuch Eiampongpaiboon; Whasun O. Chung; James D. Bryers; Kwok-Hung Chung; Daniel C. N. Chan

Abstract Objective: Gram-positive cariogenic bacteria are etiological agents in dental caries; therefore, strategies to inhibit these bacteria to reduce the incident of this disease have intensified. In this study, we investigated antibacterial activities of titanates and gold-titanates against Lactobacillus casei (Lc) and Streptococcus mutans (Sm). Materials and methods: Monosodium titanate (MST), nanomonosodium titanate (nMST) and amorphous peroxo-titanate (APT), which are inorganic compounds with high-binding affinity for specific metal ions, were used. Total bacterial proteins were measured to represent bacterial cell mass after 24u2009h incubation with gold-titanates. We further examined the effect of nMST-Au(III) concentrations (10,200,400u2009mg/L) on Lc and Sm cell viability over time via Live/Dead fluorescent staining and colony forming units (CFUs). Transmission electron microscopy (TEM) was used to determine specific locations on the bacterial cells affected by the nMST-Au(III). Results: We found all gold-titanates and APT alone reduced bacterial protein for Lc (p value <0.001) while only MST-Au(III) and nMST-Au(III) affected Sm growth (p value <0.001). Overall, nMST-Au(III) showed the most effectiveness against both Lc and Sm at 400u2009mg/L. The Live/Dead staining showed all concentrations of nMST-Au(III) affected Lc growth but only 200 and 400u2009mg/L nMST-Au(III) interrupted Sm growth. The growth curves based on CFUs/mL showed all nMST-Au(III) concentrations affected growth of both Lc and Sm. TEM images showed nMST-Au(III) attached to Lc and Sm cell wall and were internalized into both cells. Conclusions: nMST-Au(III) demonstrated potential antimicrobial activity against Gram-positive cariogenic bacteria. These results support further development of nMST-Au(III) as a potential novel material to prevent dental caries.


Journal of Esthetic and Restorative Dentistry | 2018

Esthetics and smile‐related characteristics assessed by laypersons

Cui Wang; Wenjie Hu; Ling-zhi Liang; Yan-ling Zhang; Kwok-Hung Chung

PURPOSEnThis study aimed to identify the characteristics of full-smile images assessed by laypersons using visual analog scale measurement.nnnMATERIALS AND METHODSnA total of 176 young Chinese subjects (88 males and 88 females; 20-35 years of age) with healthy dentogingival tissue were recruited to have their dynamic smiles captured using digital technology. A full-smile frame image of each subject was selected and evaluated by 22 laypersons (11 males and 11 females; 20-35 years of age) using visual analog scale measurement. Unattractive and attractive groups were designated according to the 25th percentile and 75th percentile of average visual analog scale score for the subjects, respectively. Eight smile variables were used to measure the characteristics of the full-smile images. Pearsons Chi-square test and unpaired t tests were used to analyze the data with significance level αu2009=u20090.05.nnnRESULTSnThe visual analog scale measurement scores of unattractive and attractive subgroups, respectively, were 37.89u2009±u20092.12 and 50.67u2009±u20092.75 (male subjects), and 37.14u2009±u20092.80 and 51.92u2009±u20091.99 (female subjects). VAS scores were significantly different between subgroups for both male and female subjects (Pu2009<u2009.001). No significant differences were observed between male and female subjects (Pu2009>u2009.05).nnnCONCLUSIONSnAttractive full-smiles in young Chinese subjects demonstrated higher frequencies of average or low anterior smile line, average or low posterior smile line, upward upper lip curvature, and broad and short smile with high smile index.nnnCLINICAL SIGNIFICANCEnThe smile variables of anterior smile line, posterior smile line, upper lip curvature, and smile index are predominant factors of smile attractiveness, which should be given priority to consider and manage in the anterior esthetic treatment plan.


Clinical and Experimental Dental Research | 2016

A finite element analysis of novel vented dental abutment geometries for cement-retained crown restorations

Lucas C. Rodriguez; Juliana N. Saba; Clark A. Meyer; Kwok-Hung Chung; Chandur Wadhwani; Danieli C. Rodrigues

Recent literature indicates that the long‐term success of dental implants is, in part, attributed to how dental crowns are attached to their associated implants. The commonly utilized method for crown attachment – cementation, has been criticized because of recent links between residual cement and peri‐implant disease. Residual cement extrusion from crown‐abutment margins post‐crown seating is a growing concern. This study aimed at (1) identifying key abutment features, which would improve dental cement flow characteristics, and (2) understanding how these features would impact the mechanical stability of the abutment under functional loads. Computational fluid dynamic modeling was used to evaluate cement flow in novel abutment geometries. These models were then evaluated using 3D‐printed surrogate models. Finite element analysis also provided an understanding of how the mechanical stability of these abutments was altered after key features were incorporated into the geometry. The findings demonstrated that the key features involved in improved venting of the abutment during crown seating were (1) addition of vents, (2) diameter of the vents, (3) location of the vents, (4) addition of a plastic screw insert, and (5) thickness of the abutment wall. This study culminated in a novel design for a vented abutment consisting of 8 vents located radially around the abutment neck‐margin plus a plastic insert to guide the cement during seating and provide retrievability to the abutment system.Venting of the dental abutment has been shown to decrease the risk of undetected residual dental cement post‐cement‐retained crown seating. This article will utilize a finite element analysis approach toward optimizing dental abutment designs for improved dental cement venting. Features investigated include (1) addition of vents, (2) diameter of vents, (3) location of vents, (4) addition of plastic screw insert, and (5) thickness of abutment wall.


Archive | 2015

Cemented Implant Restorations and the Risk of Peri-implant Disease: Current Status

Chandur Wadhwani; Thomas G. Wilson; Kwok-Hung Chung

The relationship between implant disease and cement has evolved from multiple sources. Initially case studies, then a positive link, was established by Wilson. More evidence is presented by evaluating failed, removed implants and establishing if cement was present on the body of the implant. Although this does not explain why the peri-implant disease occurs, it does highlight significant problems dentists are having when restoring implants with cemented restorations.

Collaboration


Dive into the Kwok-Hung Chung's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Cheng Zheng

University of Wisconsin–Milwaukee

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Armand Putra

University of Washington

View shared research outputs
Top Co-Authors

Avatar

Brian D. Flinn

University of Washington

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge