Publications by authors named "Karl Lyons"

Background: This in vitro study aimed to evaluate the effect of sodium hypochlorite (NaOCl) and ethylene diamine tetraacetic acid (EDTA) as pretreatments on the resin infiltration efficacy and acid resistance of enamel white spot lesions (WSLs).

Methods: Enamel blocks prepared from the buccal surfaces of sound human premolars were placed in a demineralisation solution for 3 days to establish artificial enamel WSLs. All the blocks with WSLs were randomly divided into four groups (n = 40 per group): RI (Control): resin infiltration only.

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As dental pulp contains the stem cells necessary for regeneration, the tooth should hold the intrinsic capacity for self-repair. A triphasic hybrid dental biocomposite (3HB) composed of biocompatible biopolymers to provide strength, antibacterial properties and protein-based cell support could provide a conducive microenvironment for the regeneration of dental structures. 3HB was incorporated into Mineral Trioxide Aggregate (ProRoot MTA) to construct a malleable injectable implant.

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Statement Of Problem: Denture stomatitis can pose serious health risks, especially to older people. Chemical denture cleaning agents must be effective, yet not adversely affect the longevity of removable dentures. Ready-to-use (RTU) neutral pH electrolyzed oxidizing water (EOW) is an effective biocide against Candida albicans biofilms on denture resins, but the effects of daily disinfection with EOW on the physical and mechanical properties of resins have not been established.

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Article Synopsis
  • This study mainly investigates how combining resin infiltration with either CPP-ACPF or bioactive glass affects the treatment of enamel white spot lesions (WSLs).
  • Eighty-four enamel blocks were artificially created and divided into three groups to analyze treatment effects, focusing on factors such as surface roughness, elemental analysis, and microhardness.
  • Results show that resin infiltration coupled with either remineralisation method enhances the surface properties of WSLs, suggesting these combinations might be effective treatment options for enamel repair.
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Objectives: This study aimed to compare changes in oral health-related quality of life (OHRQoL) resulting from three vital tooth bleaching protocols.

Methods: The participants (n = 105) were randomly assigned to one of three vital bleaching treatment groups: home bleaching (HB), in-office bleaching (IOB), or combined bleaching (CB). HB involved the use of custom-made trays and 10% carbamide peroxide for a 14-day treatment period.

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Objectives: The objective of this scoping review was to map evidence of electrolysed oxidising water (EOW) as a biocide for dental applications of relevance to older people and identify research gaps.

Background: EOW is an emerging, "green," and cost-effective biocide. There are no reviews on the landscape of EOW research as either an antiseptic or disinfectant in dental healthcare or its suitability for the oral healthcare of older people.

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The high aesthetic demands of patients have increased their requests to align their teeth using clear aligners, including Invisalign. Patients also want to have their teeth whitened for the same purpose; the use of Invisalign as a bleaching tray at night has been reported in few studies. However, whether 10% carbamide peroxide affects the physical properties of Invisalign is unknown.

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Colonization of surfaces in the human body by microorganisms is an early, essential, step in the initiation of infectious disease. We have developed in vitro assays to investigate interactions between yeast or bacterial cells and human tissues, fluids, or prostheses. Such assays can be used to identify the adhesins, ligands, and receptors involved in these interactions, for example, by determining which components of the microbe or human tissue/fluid interfere with adherence in the assay.

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The influence of thermocycling on the surface deterioration of glazed monolithic high translucent 3Y-TZP dental restorations is still unclear. The purpose of this study therefore was to evaluate low temperature degradation (LTD), elemental release and surface degradation pattern after five years of simulated clinical time. A total of 123 specimens were prepared from second-generation high translucent 3Y-TZP as per ISO 6872:2015 standards (3 mm × 4 mm × 30 mm).

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Introduction: An increasingly older population demands major remodeling of our health care system. Older adults are most likely to be affected by the oral-systemic connection due to their impairment in functional capacity and reduced ability to undertake routine oral care. An economic way to improve oral health outcomes in older populations is by involving nurses and caregivers in ensuring the maintenance of oral health for older adults.

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The aims of this study were to investigate the clinical effectiveness and patient acceptability of a modified glass ionomer cement placed using the atraumatic restorative treatment (ART) technique to treat root caries, and to carry out microbiological analysis of the restored sites. Two clinically visible root surface carious lesions per participant were restored using ART. One was restored with commercial glass ionomer cement (GIC) (ChemFil Superior, DENTSPLY, Konstonz, Germany) which acted as the control.

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The aim of the study was to investigate the microbial colonization (by species, anaerobic and facultative anaerobic bacteria) of maxillary obturators used for the restoration of maxillary defects, including during radiotherapy. Retrospective cohort study. Fifteen patients requiring a maxillary obturator prosthesis had swabs of their obturators and adjacent tissues taken at different stages of their treatment over a period of 8 years.

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Objectives: Investigate the effect of aging on the wear behavior of glazed vs polished monolithic zirconia and to establish if glazing provides protection against low temperature degradation.

Methods: 40 1-mm-diameter spheres made from four differently treated monolithic zirconia (VITA YZ® HT); polished, polished-aged, glazed and glazed-aged (n = 10), were tested in a wear testing machine (UFW200) against bovine enamel in artificial saliva as per the following settings (ISO20808:2016): ball-on-disc configuration, 5 N vertical load, 0.1 m/s sliding speed, 400 m sliding distance and 37 °C temperature.

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Objectives: Oral health self-care deteriorates in older adults due to a decreasing level of cognition increasing disability and/or a reduction in manual dexterity. Older adults in hospital care or residential care therefore increasingly need assistance for oral health care. There is an increase in dentate patients entering residential care due to advances in dentistry.

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The aim of this study was to describe the changes in oral health policies and guidelines in response to the Coronavirus disease 2019 (COVID-19) pandemic in different countries and regions around the world. Information on oral health policies and guidelines from 9 countries (Canada, China including Hong Kong, Egypt, India, Japan, New Zealand, Nigeria, Switzerland, and Thailand) were summarized, and sources of the information were mostly the national or regional health authorities and/or dental council/associations. The changes made to the oral health guidelines depended on the severity of the COVID-19 pandemic.

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(1) Background: The effect of glazing on the mechanical properties of monolithic high translucent zirconia is not well reported. Therefore, the purpose of this study was to evaluate the effect of glazing on the flexural strength of high translucent zirconia; (2) Methods: Ninety specimens were prepared from second-generation 3Y-TZP high translucent blocks and divided into three groups. Glaze materials were applied on one surface of the specimen and subjected to a four-point bending test and flexural stress and flexural displacement values were derived.

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Objective: This in-vitro study aims to study the stress distribution within the ceramic veneer-tooth system with two incisal preparation designs-butt joint (BJ) and feathered edge (FE), and to correlate these findings to the results of our previous published load-to-failure study.

Methods: Six photoelastic models were fabricated with an epoxy resin material (West System 105 Epoxy Resin/205 Fast Hardener, West System) to represent BJ and FE preparation configurations at 0° and 20° loading angulations. Lithium disilicate ceramic veneers (IPS e.

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Objective: This in vitro study aims to evaluate load-to-failure of ceramic veneers with butt joint (BJ) and feathered edge (FE) incisal preparation designs, and to correlate these results to the failure mode of the restorations.

Materials And Methods: One hundred and forty-eight typodont teeth (customized Nissin A25A-UL19B) were divided into two different preparation configurations BJ and FE and two different loading angulations, 0° and 20°. Lithium disilicate ceramic veneers (IPS e.

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Dental pathologies such as caries is one of the most prevalent diseases worldwide. Dental pulp contains stem cells capable of regenerating the dentine in the tooth, consequently, healthy dental pulp is essential for long term tooth survival. The aim of this study was to incorporate a variety of polymers that provide strength, an antibacterial substance and a protein-based polymer to provide cell support.

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Background: Maxillofacial prosthetics includes restoration of maxillary defects resulting from resection of palate and nasosinus neoplasms with obturator prostheses which may be colonized by microorganisms and function as a reservoir of infection. Patients with neoplasms commonly also require radiotherapy that can result in changes in saliva quality and quantity and changes in the oral microbial flora. The altered flora, in individuals immunocompromised from cancer therapy, increases their risk of prosthesis-related infections.

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Introduction: General dentistry is the most common area of practice, and new dentists must have the competency and skills to safely deliver patient care. In New Zealand (NZ), completion of a 5-year Bachelor of Dental Surgery (BDS) degree enables graduates to register with the Dental Council in NZ. This necessitates that the clinical component of the curriculum in final year dentistry (BDS5) transparently delivers learning opportunities and evaluates competency for independent practice.

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Purpose: To retrospectively assess implant stability quotient (ISQ) values in patients who were followed up between 1998 and 2014 and to evaluate any correlations between ISQ and clinical parameters, such as change in marginal bone level (MBL).

Materials And Methods: A total of 173 participants (65 men and 108 women; age range 21 to 85 years) and 383 implants were included. Implant location, MBL, and ISQ were recorded at surgery and at various recall times for statistical analysis.

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Purpose: To investigate the adhesion strength and bonding interface of layered porcelain to powdered cobalt-chromium (CoCr) processed by two different computer-aided manufacturing methods.

Methods: Sixteen specimens were manufactured from each of Three-dimensionally -printed/laser-sintered (LS) CoCr and milled pre-sintered (SM) CoCr. The specimens were layered with porcelain and 4-point bending was carried out.

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Objectives: To carry out a systematic review and meta-analysis of studies that investigated changes in perceived quality of life following vital tooth bleaching.

Methods: Online searches (Medline, PubMed, the Cochrane database of systemic reviews and Google scholar), bibliographic, and manual searches were carried out. Two authors independently screened the 313 articles identified from the searches and two authors extracted data, including risk of bias using the Cochrane data collection form.

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Purpose: To assess any correlations between resonance frequency analysis (RFA) and other clinical measurements, namely changes in marginal bone level.

Materials And Methods: A systematic review was performed to investigate the relationship between RFA and changes in marginal bone level. Clinical studies published up to May 1, 2018, were searched in electronic databases, including PubMed/MEDLINE, Embase, and Cochrane, using the following MeSH terms: resonance frequency analysis; implant stability quotient; RFA; and ISQ, in combination with marginal bone level; marginal bone loss; and marginal bone resorption.

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