James Tsoi

The University of Hong Kong | HKU · Faculty of Dentistry

Magnetic resonance (MR) imaging (MRI) provides compelling features for the guidance of interventional procedures, including high-contrast soft tissue imaging, detailed visualization of physiological changes, and thermometry. Laser-based tumor ablation stands to benefit greatly from MRI guidance because 3D resection margins alongside thermal distrib...

Purpose: This study explores novel solutions other than standard SBF for biomimetic evaluations of mineralization particularly for resin composites containing bioactive glass (BAG). Methods: Experimental UDMA/TEGDMA resin composites with 0.0, 1.9, 3.8 or 7.7 vol% of 45S5 BAG fillers were prepared. Besides simulated body fluid (SBF) as control, t...

Background A continuous positive airway pressure (CPAP) mask is a respiratory ventilation method used for treating breathing disorders including respiratory failure and obstructive sleep apnoea (OSA). The forces applied by a CPAP mask may affect facial development and lead to pressure ulcers. In an experimental setting, the magnitude and the distri...

Objectives: This study utilised an Artificial Intelligence (AI) method, namely 3D-Deep Convolutional Generative Adversarial Network (3D-DCGAN), which is one of the true 3D machine learning methods, as an automatic algorithm to design a dental crown. Methods: Six hundred sets of digital casts containing mandibular second premolars and their adjac...

Objective: To seek dentine analogue materials in combined experimental, analytical, and numerical approaches on the mechanical properties and fatigue behaviours that could replace human dentine in a crown fatigue laboratory test. Methods: A woven glass fibre-filled epoxy (NEMA grade G10; G10) and a glass fibre-reinforced polyamide-nylon (30% gla...

Objectives The aim of present study was to examine the effect of Porphyromonas gingivalis (P.g.) adhesion on dental zirconia by characterizing the physical and chemical properties. Methods Eighty polished-sintered zirconia discs were prepared and randomly distributed to 5 groups (n = 16): Zirconia cultured with - Group 1: broth containing P.g. for...

Durable adhesion between resin composite cement and Ti prostheses is critical for a long clinical life in dentistry. A rough surface is a prerequisite for mechanical interlocking and a special coating method, silica-coating must be followed by silanation for chemical adhesion. Commercially pure grade-2 Ti specimens were modified by silica-coating a...

Purpose To compare and contrast mechanical properties of experimental alkali-resistant (AR) glass fibre-reinforced composites (FRCs) silanised with one of three functional trialkoxysilanes: 3-methacryloxypropyltrimethoxysilane (3-MPS), 8-methacryloxypropyltrimethoxysilane (8-MOS) and 3-acryloxypropyltrimethoxysilane (3-APS). The experimental AR-FRC...

The purpose of the study was to determine the influence of preparation techniques on marginal adaptation and sealing of Biodentine™ and TotalFill® RRM bioceramic retrograde fillings. Fifty-two single-root teeth extracted for periodontal reasons were used. Root canals were instrumented using Reciproc Blue #25 and obturated using a single cone techni...

The presence of Si on the Ti surface is quintessential for a strong, durable silane‐based adhesion utilized in several dental applications. Silica‐coating and silanization form durable ≡Si‐O‐Si≡ bonds, which might have a positive effect on resin‐Ti adhesion. This laboratory study studied the effect of strong acids, their blends, and silica‐coating...

Purpose To compare and contrast mechanical properties of experimental alkali-resistant (AR) glass fibre-reinforced composites (FRCs) silanised with one of three functional trialkoxy silanes: 3-methacryloxypropyltrimethoxysilane (3-MPS), 8-methacryloxypropyltrimethoxysilane (8-MOS) and 3-acryloxypropyltrimethoxysilane (3-APS). The experimental AR-FR...

Objectives: The aim of the present study was to examine the plaque removal effectiveness of a personalised 3D-printed dental plaque removal mouthguard device in a clinical trial setting. Methods: A personalised 3D-printed mouthguard was developed to clean dental plaque using micro-mist. A clinical trial was conducted to examine the plaque remova...

Durable adhesion between resin composite cement and Ti prostheses is critical for a long clinical life. A rough surface is a prerequisite for mechanical interlocking and silica-coating followed by silanation for chemical adhesion. Commercially pure grade-2 Ti specimens were modified by silica-coating and silanized with an experimental silane blend...

Purpose To investigate mechanical properties of experimental resin composites containing 8-methacryloxyoctyltrimethoxysilane (MOS) and a more commonly used silane monomer, 3-methacryloxypropyltrimethoxysilane (MPS). Materials and methods MOS and MPS were hydrolysed in 95vol% ethanol solution at pH 4 for 1 h before silanisation of SiO2-based bioact...

Background: Autogenous tooth bone graft material (AutoBT) has been advocated as a bone substitute when conducting alveolar ridge preservation. This study is aimed at using a radiomics approach in order to evaluate and testify whether AutoBT can stimulate bone growth during socket preservation in severe periodontal cases. Materials and methods: F...

Quaternary ammonium compounds (QACs) have been widely used due to their excellent antimicrobial activity. However, using the technology where nanomaterials are employed as drug carriers to deliver QAC drugs has not been fully explored. In this study, mesoporous silica nanoparticles (MSNs) with short rod morphology were synthesized in a one-pot reac...

This study was conducted as a means to evaluate the stress distribution patterns of anterior ceramic resin-bonded fixed partial dentures derived from different materials and numerous connector designs that had various loading conditions imposed onto them through the utilization of the finite element method. A finite element model was established on...

Purpose To investigate mechanical properties of experimental resin composites contain 8-methacryloxyoctyltrimethoxysilane (MOS) and a commonly used silane, 3-methacryloxypropyltrimethoxysilane (MPS). Materials and methods MOS and MPS were hydrolysed in 95vol% ethanol solution at pH 4 for 1h before silanisation of SiO2-based bioactive glass powder...

Artificial Intelligence (AI) is the ability of machines to perform tasks that normally require human intelligence. AI is not a new term, the concept of AI can be dated back to 1950. However, it has not become a practical tool until two decades ago. Owing to the rapid development of three cornerstones of current AI technology—big data (coming throug...

Recent studies have shown that global variation in body proportions is more complex than previously thought as some traits formerly associated with climate adaptation are better explained by geographic proximity and neutral evolutionary forces. While the recent incorporation of quantitative genetic methodologies has improved understanding of patter...

Background The aim of the study was to investigate whether the citric acid and rough surface have a synergistic effect leading to severe wear behavior of resin composite. Materials and methods Disk-shaped (Ø15 × 1.5 mm) specimens of resin composite ( n = 12) with different initial roughness were prepared. Reciprocating ball-on-flat wear tests were...

Objectives: To develop a risk of bias tool for pre-clinical dental materials research studies that aims to support reporting of future investigations and improve assessment in systematic reviews. Methods: A four-stage process following EQUATOR network recommendations was followed, which included project launch, literature review, Delphi process and...

This review aims to provide a comprehensive analysis of the characterizations of bioactive glass (BAG)-loaded dental resin-based composite materials. Online databases (Web of Science, PubMed, and Science Direct) were used to collect data published from January 2011 to January 2022. Only BAG-containing resin adhesive and resin restorative composites...

Objective: Dentists use a large number of dental materials to treat patients, mainly for pain relief, improved oral function, and orofacial appearance purposes. These materials supposably have been clinically tested and registered before launching onto the market. In terms of clinical testing, despite various objective and subjective assessments t...

The wear behavior of dental restorative materials is highly related to the biolubricating medium in the oral environment. Bacteria, along with their metabolic products, are essential substances in the oral cavity and have not been studied as a potential factor affecting lubrication performance during mastication. In this study, the effects of the S...

Purpose: Measurement of bacterial adhesion has been of great interest for different dental materials. Various methods have been used for bacterial counting; however, they are all indirect measurements with estimated results and therefore cannot truly reflect the adhesion status. This study provides a new direct measurement approach by using a simpl...

Electrospun nanofibers have been widely used in dentistry due to their excellent properties, such as high surface area and high porosity, this bibliometric study aimed to review the application fields, research status, and development trends of electrospun nanofibers in different fields of dentistry in recent years. All of the data were obtained fr...

This study aimed to compare the occlusal morphology and fracture behavior of lithium disilicate ceramic dental crowns on 12 human participants' premolar #45 designed by a knowledge-based AI (CEREC, biogeneric individual function, BI) and different human personnel (experienced technician, TD, and trained dental students, AD) using CAD software. Digi...

Objectives: To evaluate the inhibitory effect of a novel mussel-inspired monomer (N-(3,4-dihydroxyphenethyl)methacrylamide (DMA) on the soluble and matrix-bound proteases. Methods: The inhibitory effect of DMA (0, 1, 5, and 10 mM) and 1 mM chlorhexidine (CHX) dissolved in 50% ethanol/water on soluble recombinant human matrix metalloproteinases (...

Purpose: To investigate the error accumulation and distribution through various stages of the digital workflow for complete-arch implant-supported framework fabrication. Materials and methods: A resin model of edentulous maxilla with 6 dental implants was scanned using an intraoral scanner for 10 times (Complete-digital group). Ten conventional...

Objectives To evaluate the biocompatibility and mechanical properties of experimental bis-phenol-A and bis-GMA free E-glass fiber-reinforced composites (FRCs) prepared with hexanediol dimethacrylate (HDDMA) based resin. Methods Two ratios of HDDMA/TEGDMA resin were evaluated: exp-1 (70/30 wt.%) and exp-2 (50/50 wt.%) with two bis-GMA resin control...

The objective of this study was to characterize natal and neonatal teeth using micro-computed tomography. A total of 4 natal and 11 neonatal teeth were used for the analysis. The reconstructed scans were assessed for the maximum enamel/dentin thickness and mineral density (MD). The scanned specimens were 3D reconstructed to qualitatively determine...

Abstract: This laboratory study aimed to compare, contrast, and evaluate the effect of a novel dual surface modification method on the adhesion strength of resin composite cement to titanium. C.p.-2 grade titanium samples were silica-coated, etched with HNO3(69vol %) or a blend of HCl (35vol %) and H3PO4 (85vol %), for 1 h at 80ᵒC. Surface roughnes...

Midpalatal suture was analysed with cone beam computed tomography to identify its maturation with respect to age and maxillary-complex growth in 72 patients 9- to 21-year-old. Maxillary-complex was divided in premaxillary, maxillary, and palatine segment. Interdigitation and ossification of midpalatal suture, its density relative to hard tissues an...

Purpose/Aim This study aimed to evaluate single crown restorations generated by CEREC biogeneric function, designed by experienced dental technician, and designed by dental student using a dental CAD software. Occlusal morphological parameters were evaluated by superimposing and analyzing the digital datasets, while fracture resistance was assessed...

Purpose/Aim This study aims at explores immersion solutions other than standard SBF that could evaluate mineralization of dental resin composites containing low percentage bioactive glass (BAG). Materials and Methods Experimental UDMA/TEGDMA resin composites containing total 25 vol% glass fillers (with 0.0, 1.9, 3.8 or 7.7 vol% of 45S5 bioactive g...

Objectives To compare 2 implant scan bodies with different geometry on the accuracy of the virtual alignment process in the digital workflow. Materials and Methods A master model of the edentulous maxilla with 6 implants and multi-unit abutments (MUA) inserted was fabricated. Six dome-shaped and cuboidal scan bodies were mounted on the MUAs respec...

Objective: This study aimed to compare the effectiveness of various combinations of dental suction devices in reducing the amount and distance of spread of aerosols and droplets using an electrical surgical motor model with a self-irrigation system. Materials and Methods: In a standard single-chaired air-conditioned ventilated dental clinic, an ele...

The present dry-mandible study evaluated the presence of the mental (MF), lingual (LF), and retromolar (RMF) foramina to assess the accuracy of CBCT in detecting these anatomical structures. In total, 38 human dry mandibles were analyzed (30 men, 8 women; mean age: 61.9 ± 13.7 years). CBCT scans were taken using low-dose parameters, and LF, MF, and...

Fusobacterium nucleatum (F. nucleatum) is a gram-negative obligate anaerobe bacterium that threatens human periodontal health. It can cause many oral diseases, including periodontitis, gingivitis and peri-implantitis, and even some diseases such as colorectal cancer are related to it. This paper aims to develop a novel and simple surface modificati...

Telescopic systems constructed using computer aided design and computer aided manufacture (CAD/CAM) can overcome many drawbacks associated with conventionally constructed ones. Since retention is considered the most important function of these retainers, this scoping review aimed to discuss and summarize the parameters that affect this function in...

Objectives To develop a novel auxiliary device for improving the accuracy of intraoral implant scanning in the complete-edentulous arch. Materials and methods A standard model of edentulous maxilla with 6 dummy implants was prepared. Scan bodies were attached to the model, which was scanned by a laboratory scanner. A simulated mucosa (Group 0), a...

Numerous approaches have been developed to improve the resin-dentin bond performance, among which the bio-application of mussel-derived compounds have drawn great attention recently. To assess the performance of N-(3,4-dihydroxyphenethyl)methacrylamide (DMA), a mussel-derived compound, as a functional monomer in dental adhesive, its potential prope...

The study objective was to examine the acid-resistance potential of enamel carious lesions treated with arginine (Arg)-sodium fluoride (NaF) varnishes using nano-mechanical testing and chemical mapping. L-arginine (at 1%, 2%, & 4%) was incorporated in 5% NaF varnish. The experimental/control groups were: 1% Arg-NaF, 2% Arg-NaF, 4% Arg-NaF, NaF, and...

Objectives. To evaluate the anti-proteolytic and cross-linking effect of N-(3,4-dihydroxyphenethyl)methacrylamide (DMA) on the demineralized dentin matrix in vitro. Methods. Four experimental solutions were selected: 50% ethanol/water solution (Control); 1, 5, and 10 mmol/L DMA dissolved in 50% ethanol/water solution. Sound human molars were sectio...

Spatial deviations of the temporomandibular joint (TMJ) after oncological mandibular reconstruction are important to the aesthetic and functional rehabilitation. The aim of this study was to clarify whether and how three dimensionally (3D) printed patient-specific surgical plates, and the preservation of the condyle or ramus, affect spatial deviati...

Being as a non-pharmacological medical intervention, low-magnitude high-frequency vibration (LMHFV) has shown a positive effect on bone induction and remodeling for various muscle diseases in animal studies, among which dental implants osteointegration were reported to be improved as well. However, whether LMHFV can be clinically used in dental imp...

Objectives The present study aimed to evaluate the effect of restoration thickness, CAD/CAM material, and 6 months of artificial saliva storage on the fracture resistance of occlusal veneers. Materials and methods A total of 84 intact maxillary molars were sectioned 4.0 mm occlusal to the cementoenamel junction to expose the dentine. The teeth wer...

Objectives The present work describes the status and contents of The Human Bone Collection of the Faculty of Dentistry at the University of Hong Kong. Materials and methods The Collection originates from the 1980s and became officially established in 2017 for teaching and research purposes. Most of the Collection consists of unclaimed human remain...

Objective To give a current review of the mechanism of mussel adhesion, the application of mussel-inspired compounds in dentistry and the challenges associated with clinical application. Methods Inspired by the wet adhesion property of 3,4-dihydroxyphenol-l-alanine (Dopa) in mussel plaques, various chemical compounds have been synthesized to mimic...

Background. Monolithic restorations made of translucent yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) have become popular over the past few decades. However, whether aging affects the color and translucency of monolithic translucent Y-TZP is unclear. Objective. The aim of this systematic review and meta-analysis of in vitro studies was...

Background The fit of implant‐supported prostheses is of prime importance for the long‐term success of implant therapy. Purpose This systematic review aimed to evaluate recent evidence on current techniques for assessing implant‐framework misfit, its associated strain/stress, and whether these misfits are related to mechanical, biological, and cli...

Background: Flavonoids in Chinese Medicine have been proven in animal studies that could aid in osteogenesis and bone formation. However, there is no consented mechanism for how these phytochemicals action on the bone-forming osteoblasts, and henceforth the prediction model of chemical screening for this specific biochemical function has not been...

The study aimed to compare three methods for determining total (TF) and total soluble fluorides (TSF) in 5 child formula dentifrices (CFD) using Inter-method reliability (IMR) statistical approach. The methods were direct acid-hydrolysis (DM), the least-time-consuming method; Modified direct acid-hydrolysis with standard-addition method (MDM), ISO...

During the current coronavirus disease 2019 (COVID-19) pandemic, dental education and training requiring face-to-face interaction must prioritize infection prevention and the safety of students, staff, and patients. In July 2020, the Association for Dental Education, Asia Pacific (ADEAP) published safety guidelines for safe dental education during...

Objective(s): To: 1) examine the fluoride concentrations in commercial child formula dentifrices (CFD)s; and 2) investigate the effect of arginine incorporation in CFDs on fluoride bioavailability. Study Design: Five commercial CFDs were examined for fluoride concentrations. Total, total soluble, and insoluble fluorides in CFDs were determined by t...

Objectives: To use both absolute anteroposterior maxillary complex length (APMCL) and relative APMCL to investigate the relationship between the maxillary complex, its individual bony segments, and their association to the anterior cranial base. In addition, the relationship between length and position of the maxillary complex was analyzed. Materia...

Purpose: To seek a simple solution that can recycle and regenerate dental CAD/CAM zirconia green blanks from its waste residuals. Methods: Waste residuals (3M® Lava™ Plus HT) were pulverized after dry milling and cutting, and subsequently sieved before pickling in a 0.5 M nitric acid. These powders were then dry-pressed and pre-sintered into blo...

Statement of problem Lithium disilicate (LD) is a popular dental ceramic and has been a focus of dental research. Nevertheless, a quantified literature analysis focusing on the research of lithium disilicate is lacking. Purpose The purpose of this bibliometric analysis was to review the progress of research into lithium disilicate in dentistry, i...

Objectives: To compare the accuracies of 4 laboratory scanners using a new custom-made block for complete-arch implant rehabilitation. Materials and methods: A block comprised 4 cylinders, with 2 in the anterior (0° angulation) and 2 in the posterior region (45° distal angulation) (Experimental group) and a standard block with 2 parallel cones i...

Background: The study examined the effect of arginine incorporation in child formula dentifrices (CFD) on fluoride bioavailability. Methods: L-arginine (L-Arg) and L-arginine monohydrochloride (L-Arg.HCl) at 2% w/w of dentifrices were incorporated in five tested commercial CFDs. Total, total soluble, and insoluble fluorides in CFDs were determined...

Current control of pathogenic bacteria at all biomaterial interfaces is poorly attuned to a broad range of disease-causing pathogens. Leading antimicrobial surface functionalization strategies with antimicrobial peptides (AMPs), Defensins, have not shown their promised efficacy. One of the main problems is lack of stability and swift clearance from...

Objective: The purpose of this systematic review was to summarize scientific evidence that evaluates in vitro fracture and fatigue strength of occlusal veneers in different thicknesses, CAD/CAM materials, and under different aging methodologies. Materials and methods: An electronic search of 3 English databases (The National Library of Medicine (ME...