Laurence James Walsh

The University of Queensland | UQ · School of Dentistry

Background: To evaluate the cyclic fatigue resistance of rotary endodontic nickel-titanium instruments using both experimental and finite element methods. Methodology: Four different proprietary rotary endodontic instruments (PTG, PTU, VB, and TRN) were subjected to cyclic fatigue tests through a custom-built fixture (n = 30 for each group) and tes...

Knowledge, attitudes and performance of Iranian endodontists regarding patients with kidney diseases Fatemeh Arabpour1, Maryam Kuzekanani2, Laurence Walsh3, Moghaddameh Mirzaei4 1Department of Orthodontics, School of dentistry, Shahid Sadoughi university of medical sciences, Yazd, Iran 2Department of Endodontics.Kerman university of medical science...

Objective: The high prevalence of chronic kidney disease in the community, especially in older patients,makes their management an important aspect of clinical practice. The aim of this study was to evaluatethe knowledge attitudes and performance of Iranian endodontists regarding patients with chronic kidneydisease (CKD).Methods: This cross-sectiona...

This study aimed to evaluate and compare the effects of ambient temperature and post-manufacture heat-treatment on the mechanical behavior of nickel-titanium (NiTi) wires. Four types of commercial NiTi variants (Stock NiTi, heat treated “Blue”, “Gold”, “Superflex”, all Dentsply Maillefer, Ballaigues, Switzerland) were stressed in a tensile testing...

Objective To assess literature for the effectiveness and impact of femtosecond (fs) laser irradiation for surface processing of enamel and dentine. Materials and methods This systematic review followed PRISMA guidelines. Criteria for inclusion and exclusion were established, and searches undertaken in the PubMed/MEDLINE, Embase and, Scopus databas...

Micro-ribonucleic acid (miRNA)-based therapies show advantages for bone regeneration but need efficient intracellular delivery methods. Inorganic nanoparticles such as mesoporous bioactive glass nanoparticles (MBGN) and mesoporous silica nanoparticles (MSN) have received growing interest in the intracellular delivery of nucleic acids. This study ex...

Despite the many treatment modalities offered to prevent or manage peri-implantitis, there is currently a lack of high-quality evidence that supports any approach being regarded as a gold standard. Given that methods such as hand scaling with metal instruments and ultrasonic scaling may damage the implant surfaces, it is important to identify metho...

Objectives: Debridement methods may damage implant surfaces. This in vitro study investigated 8 debridement protocols across three implant surfaces to assess both biofilm removal and surface alterations. Material and methods: 160 commercially pure titanium disks were treated to simulate commercially available titanium implant surfaces- smooth, a...

Background: This prospective cohort study aimed to evaluate the antibody responses in non-invasive gingival crevicular fluid (GCF) and unstimulated whole saliva to the SARS-CoV-2 Spike unit 1 receptor-binding domain (S1-RBD) protein following administration of the mRNA BNT162b2 vaccine. Materials and methods: This longitudinal study recruited 37...

Following the global COVID-19 pandemic, nanotechnology has been at the forefront and enables the fast development of diagnostic tools, vaccines and anti-viral treatment for this novel virus (SARS-CoV-19). In this review, we first summarize the nanotechnology for the detection of SARS-CoV-2 including nanoparticle-based techniques such as rapid antig...

The development of protocols for laser-assisted therapy demands strict compliance with comprehensive operating parametry. The purpose of this investigation was to examine the accuracy of correlation between laser control panel and fibre emission power values in a selection of diode dental lasers. Through retrospective analysis using successive syst...

The internal topography of the root canal is complex, especially for the mesial root of the permanent first molar. In response to such challenges, enhanced irrigation protocols have been developed, using laser pulses to agitate fluids and enhance the removal of microbial deposits. The aim of this laboratory study was to assess the effectiveness of...

Objectives This study evaluated particle spread associated with various common periodontal aerosol-generating procedures (AGPs) in simulated and clinical settings. Materials and methods A simulation study visualized the aerosols, droplets, and splatter spread with and without high-volume suction (HVS, 325 L/min) during common dental AGPs, namely u...

Background Laser-fluorescence diagnostic technology for real-time clinical assessment of residual bacteria could help assist in determining the endpoints for root canal debridement. Sodium hypochlorite (NaOCl) can however quench fluorescence and lead to false low reading. This study aims to evaluate various antioxidant for their ability to recover...

As a range of materials used in endodontics may cause tooth discolouration, exploration of factors responsible for the darkening of the tooth crown or root is warranted. This narrative review paper discusses the range of technical factors that apply in laboratory studies that assess endodontic discolouration. As an example of how these factors oper...

Subsurface remineralization can be promoted by the topical application of nanoparticles of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). To assess changes in enamel white spot lesions, an in situ proof-of-concept investigation was performed using 5 subjects (all of whom were healthy young adults) with a cross-over study design. Custo...

Recent studies have shown prebiotic effects of casein phosphopeptides on dental plaque microflora in orthodontic patients. The aim of this study was to assess dental plaque ecological changes in orthodontic patients that resulted from the application of a topical crème containing casein phosphopeptides and 900 ppm fluoride (GC Tooth Mousse Plus™) (...

This study examined the effect of various root canal irrigants and medicaments on dentin fluorescence elicited by 655nm visible red laser light. To replicate clinical use, irrigants were applied onto dentin samples for 2 minutes, while medicaments were applied for 2 weeks. Fluorescence values tracked from baseline across the following to 24 hours,...

Objectives: Workplace non-sharps injuries are a common occurrence in a dental school setting. In dentistry, the importance of preventing non-sharps injuries is often overlooked due to emphasis on sharps-related injuries. The aim of this research was to analyse the incidences of non-sharps injuries over an 11-year period in a dental school to ident...

Purpose: This in vitro study compared root canal preparation in curved mesiobuccal canals of molar teeth using either the One Shape™ or the Neoniti (Neolix) rotary NiTi single-file systems, assessing canal transportation, instrument separation and time required for preparation. Methods. Extracted maxillary and mandibular human molar teeth with mes...

Peri-implantitis is the major cause of the failure of dental implants. Since dental implants have become one of the main therapies for teeth loss, the number of patients with peri-implant diseases has been rising. Like the periodontal diseases that affect the supporting tissues of the teeth, peri-implant diseases are also associated with the format...

Finite element analysis has been a valuable research tool for rotary nickel-titanium endodontic files over the last two decades. This review aims to summarise and critique the methodology as used in currently available endodontic literature for finite element analysis of rotary nickel-titanium instruments. An electronic literature research in PubMe...

Introduction : This study aimed to assess changes in the fluorescence characteristics of Enterococcus faecalis in human dentine over a period of 24 hours following treatment with endodontic irrigants. Method : Sterilised, non-functional extracted third molars were embedded in acrylic resin and uniformly sectioned into 2mm thick dentine sections. A...

Periodontitis is a chronic complex inflammatory disease associated with a destructive host immune response to microbial dysbiosis, leading to irreversible loss of tooth-supporting tissues. Regeneration of functional periodontal soft (periodontal ligament and gingiva) and hard tissue components (cementum and alveolar bone) to replace lost tissues is...

Photo‐activated disinfection using photosensitisers has been proposed as an adjunct to conventional endodontic therapy for additional disinfection and improved treatment outcomes. This systematic review aims to investigate the effectiveness of photosensitisers used in laser endodontics disinfection. A comprehensive literature search is conducted to...

Dental aerosol-generating procedures produce a large amount of splatters and aerosols that create a major concern for airborne disease transmission, such as COVID-19. This study established a method to visualise splatter and aerosol contamination by common dental instrumentation, namely ultrasonic scaling, air-water spray, high-speed and low-speed...

MicroRNA-based therapy for bone repair has shown promising results for regulating stem cell proliferation and differentiation, however, an efficient and stable vector for delivery of microRNA (miRNA) delivery is still a major gap in this field. The present study explored the stability and functionality of PEI modified mesoporous silica nanoparticle...

Gene therapy can be an effective treatment modality for some severe genetic diseases. Despite efforts to improve their performance, non-viral gene delivery methods remain inefficient and costly. As an alternative to viral vectors, cationic liposomes have a good safety profile and low immunogenicity, but relatively low transfection efficiency. They...

Loss of dental tissues and structure due to dental caries, periodontal diseases, bone resorption, tooth loss, and oral lesions impacts oral function as well as systemic health. Achieving true regeneration of the oral tissues is a major challenge in the oral biosciences. With recent advancements in cellular biology and biotechnology, regenerative th...

Aims This study investigated caries predictors in 378 children remaining from a birth cohort of 1,052 at 7 y and compared the efficacy of home visits (HVs) and telephone contacts (TCs) for early childhood caries (ECC) prevention. Methods The HVs or TCs were made at ages 6, 12, 18, 30, and 42 mo with annual dental clinic examinations at ages 2 to 7...

The application of mesoporous silica nanoparticles (MSNs) as drug delivery systems to deliver drugs, proteins, and genes has expanded considerably in recent years, using in vitro and animal studies. For future translation to clinical applications, the biological safety aspects of MSNs must be considered carefully. This paper reviews the biosafety o...

This study aimed to use multiple methodologies, including a novel usage of scanning electron microscopy (SEM), to evaluate the antimicrobial actions of sodium hypochlorite (NaOCl) admixed with clodronate or etidronate in root canal irrigation. The study also examined the usefulness of colony counting as a biofilm assessment methodology. Seven day E...

In bone regenerative engineering, the biomechanical performance of the scaffold at the bone-tissue interface is a key consideration. The evaluation of this parameter is a crucial step in designing, optimizing and manufacturing of bone substitute materials for clinical application, but is as yet comparatively unexplored. To this end, we utilized a n...

Purpose: Missed additional canals are one of the most important reasons for RCT failures in molar teeth. This study aimed to determine the prevalence and distribution of middle mesial canals in mandibular first molars of the Kerman population. Materials and methods: A retrospective study was performed on de-identified cone beam image sets from 3...

This article has been accepted to be pubilshed in the international journal of dentistry and soon could be accessed on line.

Continuous chelation involves the simultaneous use of sodium hypochlorite and a chelating agent. Given the combination of a proteolytic agent and a demineralising chelator, this study aimed to investigate whether mixtures containing the weak chelators etidronate or clodronate and sodium hypochlorite could adversely affect the mechanical strength of...

The aim of the study was to investigate the effects of neodymium: yttrium aluminium garnet (Nd:YAG) (1064 nm) and erbium: yttrium aluminium garnet (Er:YAG) (2940 nm) laser energy on titanium when delivered with conventional optics (focusing handpieces or plain ended optical fibres) or with a conical tip. Machined and micro-roughened implant discs w...

There are concerns that general dentists (GDs) and dental specialists may be prescribing antibiotics inappropriately. This study explored the prescribing habits and decision-making processes of GDs versus oral and maxillofacial surgeons (OMFSs). A case-based online questionnaire was used to examine the prescribing of therapeutic and prophylactic an...

Background The ability to determine the effectiveness of root canal disinfection in real-time prior to the final root filling could significantly influence the management and treatment outcomes of root canal therapy. Laser fluorescence devices can detect bacterial fluorescence in real-time, however since quenching of fluorescence is a possible conf...

Given that oropharyngeal squamous cell carcinoma (OPSCC) have now surpassed cervical cancer as the most common human papillomavirus (HPV)‐driven cancer, there is an interest in developing non‐invasive predictive biomarkers to early detect HPV‐driven OPSCC. A total of 665 cancer‐free individuals were recruited from Queensland, Australia. Oral HPV16...

This study evaluated the stability of continuous chelation mixtures of clodronate admixed with sodium hypochlorite at room temperature (23°C), at root canal temperature (34–35°C) and in refrigerated storage (2–4°C). In continuous chelation, one solution containing a chelator and sodium hypochlorite simultaneously disinfects and removes organic matt...

Oropharyngeal cancer (OPC) caused by human papillomavirus (HPV) is a rising global concern. Early lesions are small and are often located in difficult to access areas (such as the crypts of the tonsils or base of tongue). Unlike cervical cancer, there is no standard or routine screening program for HPV-driven OPC. HPV DNA from OPC tumors may shed d...

Purpose: This study investigated whether selected natural products could specifically target the growth of a caries-associated bacterial species (Streptococcus mutans) without affecting the viability of a health-associated oral commensal bacterial species (Streptococcus sanguinis). Materials and methods: Agar diffusion assays were used to screen...

Objective: The fluorescence properties of tooth-colored restorative materials can vary according to the shade of the material. The objective of this study was to investigate the fluorescence behavior of different shades of selected contemporary tooth-colored restorative materials when illuminated with violet light (405 nm wavelength). Methods: F...

Bone tissue engineering involves the combined use of materials with functional properties to regenerate bone. Nanohydroxyapatite (nHA) can influence the behavior of cells. The functional and structural properties of nHA can be controlled during nanoparticle synthesis. This review defines the relationship between the attributes of nHA nanoparticles...

Introduction: Mixtures of clodronate with sodium hypochlorite (NaOCl) better maintain free available chlorine (FAC) than etidronate-hypochlorite mixtures. This research aimed to compare organic tissue dissolution and residual FAC between clodronate and etidronate mixtures. Additionally, clodronate-hypochlorite mixtures lose no FAC over several hou...

Laser fluorescence (LF) and differential reflectometry (DR) are two new optical methods which have been used to help diagnose subgingival deposits of dental calculus. This study compared the performance of LF using the KEY3 laser system versus DR using the DetecTar system under controlled laboratory conditions designed to simulate clinical conditio...

Biofilms can be produced by multiple species or by a single strain of bacteria. The biofilm state enhances the resistance of the resident microorganisms to antimicrobial agents by producing extracellular polymeric substances. Typically, antibiotics are used to stop the growth of bacteria, but emerging resistance has limited their effectiveness. Bac...

We are pleased to announce the launch of a new platinum open access journal entitled Bioengineering International. Bioengineering International is a peer-reviewed journal that encourages worldwide academic and scientific researchers to share their original research work, reviews and commentaries. The journal will provide an extensive platform for t...

Aim: During removal of resin-based composite (RBC) restorations, removal of adjacent sound tooth structure can easily occur. The aim of the study was to compare the fluorescence-aided identification of restorations (FAIR) method with the conventional method (CM) using white light illumination for the selective removal of tooth-colored RBC restorat...

Aim: To identify chelators which when mixed with sodium hypochlorite (NaOCl) are stable, exhibiting minimal loss of free available chlorine (FAC) over 80 minutes and to further investigate potential mixtures by assessing FAC over 18 hours and the capacity to remove smear layer. Methodology: 0.25 M EDTA (10%), 0.25 M EGTA (egtazic acid), 0.25 M C...

During antemortem and postmortem comparison of dental records of carbonized victims, restorations may be part of such records. The objective of this study was to evaluate the effect of heat on the fluorescence behavior of contemporary tooth‐colored restorative materials and natural tooth structure when subjected to range of temperatures, using illu...

Introduction Ecological approaches to dental caries prevention play a key role in attaining long-term control over the disease and maintaining a symbiotic oral microbiome. Objectives This study aimed to investigate the microbial ecological effects of 2 interventional dentifrices: a casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) dentif...

Purpose: This paper discusses the cariostatic mechanisms of some of the most promising natural products and explores the research directions that are needed to translate the potential of natural products into commercial oral care products for dental caries control. Materials and methods: The search strategy for this narrative review involved per...

Background: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) acts as a salivary biomimetic that provides bioavailable calcium and phosphate ions to augment fluoride-mediated remineralisation of early caries lesions. However, there are indications that it may also have beneficial ecological effects on the oral microbiome. Objective: Th...

As patients progress from childhood through to teenage years, they progress through periods of high caries risk as they undergo changes in lifestyle and oral microflora. Removable or fixed orthodontic treatment also alters the oral microflora and can dramatically increase caries risk. This paper outlines ways to identify the transition to higher ca...

Bioactive polyphenol components of cranberry (Vaccinium macrocarpon) are known to have virulence attenuating effects against several cariogenic virulence properties responsible for dental caries pathogenesis. In particular, cranberry A-type proanthocyanidins and flavonols have demonstrated potent inhibitory effects against cariogenic virulence targ...

Objective: To investigate the effect of cranberry extracts on saliva-derived polymicrobial biofilms with regards to biofilm biomass, acidogenicity, exopolysaccharide (EPS)/microbial biovolumes, colony forming unit (CFU) counts, and the relative abundance of specific caries- and health-associated bacteria. Methods: Saliva-derived polymicrobial bi...

Purpose: The purpose of this study was to investigate the effects of polyphenol-rich cranberry extracts on dual-species Streptococcus mutans-Candida. albicans biofilms implicated in contributing to the severity of early childhood caries. Methods:S. mutans-C. albicans biofilms were grown on saliva-coated hydroxyapatite discs (s-HA) mounted on the hi...

Dark‐colored fruit berries are a rich source of polyphenols that could provide innovative bioactive molecules as natural weapons against dental caries. High‐quality extracts of cranberry, blueberry, and strawberry, and a combination of the three berry extracts (Orophenol), were used to treat 24‐h‐old Streptococcus mutans biofilms. The grown biofilm...

Introduction Tetrasodium etidronate (Na4 etidronate) and tetrasodium EDTA (Na4 EDTA) are chelators that can combine with sodium hypochlorite (NaOCl) as a 1-mix endodontic irrigant in a process called continuous chelation. The therapeutic window of these mixtures is determined by the chemical reaction between NaOCl and the chelator. At room temperat...

Contemporary caries prevention protocols recommend not only effective remineralizing agents but also ecological measures to reverse the dental plaque dysbiosis responsible for the disease pathogenesis. There is a high‐level of evidence supporting the remineralizing efficacy of Casein Phosphopeptide‐Amorphous Calcium Phosphate (CPP‐ACP) from studies...

Aim The aim of the present study was to investigate fracture resistance of implant‐supported zirconia‐based crowns (monolayer vs bilayer) cemented to hybrid abutments. Methods Monolayer and bilayer zirconia crowns were constructed and cemented to zirconia hybrid abutments. Crowns were divided into two subgroups: (a) untreated control group; and (b...

Victim identification using dental records involves antemortem and postmortem comparison of dental charts. Since dental restorations may be part of such records, identifying them accurately is critical. The objective of this study was to compare the diagnostic reliability and validity of two optical methods for identifying tooth‐colored restoration...

Data on complaints was extracted from annual reports of the national regulator (the Australian Health Practitioner Regulation Agency, AHPRA). For co-regulated Australian jurisdictions, data on complaints were derived from the annual reports of the Office of the Health Ombudsman (Qld) and the NSW Dental Council. The major patterns were compared to t...

The anti-microbial activity of calcium hydroxide pastes used in endodontics is dependent on establishing high levels of hydroxyl ions in dentine. This study investigated hydroxyl ion diffusion from different commercial calcium hydroxide pastes using a novel colourimetric method. In this method, human tooth roots were stained with anthocyanin dye, w...

Aetiological concepts of dental caries have evolved over the years from being considered as a disease initiated by nonspecific microorganisms, to being regarded as an 'infectious' disease caused by specific bacteria, to the current paradigms that emphasise a 'mixed bacterial-ecological approach' as being responsible for lesion initiation and pathog...

The aim of this study was to investigate the influence of tip design on patterns of laser energy dispersion through the dentine of tooth roots when using near-infrared diode lasers. Diode laser emissions of 810 or 940 nm were used in combination with optical fiber tips with either conventional plain ends or conical ends, to irradiate tooth roots of...

Contemporary paradigms of dental caries aetiology focus on the ecology of the dental plaque biofilm and how local environmental factors can modulate this to cause disease. The crucial role that a healthy oral microbiome plays in preventing caries and promoting oral health is also being increasingly recognized. Based on these concepts, several ecolo...