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OBJECTIVE: This systematic review examines the effect of age on changes to coronal dentin properties. DESIGN: Pubmed, Cinhal, Scopus, Web of Science and the Cochrane Database were searched for publications up to 31 December 2021. All studies were uploaded and reviewed using Covidence software. At different stages of the review, study selection and the extraction of data were completed by six independent reviewers based on the eligibility criteria. The quality of the articles was judged based on JBI Critical Appraisal Checklist for quasi-experimental studies. RESULTS: Twelve studies satisfied the eligibility criteria and were included. Dentin characteristics and mechanical properties alter with age, and spatially within a tooth to depend on tubule orientation. Age-related mineral deposition within tubules, and collagen maturation in intertubular dentin compound the spatial effects on mechanical properties. Mechanical properties depend on collagen fiber orientation and apatite alignment relative to dentin tubules, characteristic differences in peritubular and intertubular dentin, and relative dentin tubule distribution within a tooth. The bulk of the research focussed on age-related apatite effects, although many reported limited understanding of changes to collagen, particularly in intertubular dentin. CONCLUSION: Investigations into the effect of age, depth, site and location on dentin collagen are warranted to minimize tooth loss in older populations by providing targeted adhesive, restorative or preventative interventions.
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Dentina , Diente , Adulto , Humanos , Anciano , Colágeno , Apatitas , MineralesRESUMEN
To investigate age and site-related changes to human dentin collagen, sound human teeth collected from donors aged 13-29 (young) and 50-74 (aged) years (n = 9/group) were cut to shallow and deep sites. Dentin collagen orientation and fibril bundling was investigated using the Picrosirius Red (PSR) stain observed under cross-polarized light microscopy (Pol), and collagen distribution was investigated using Confocal Laser Scanning Microscopy (CLSM). Collagen types III to I distribution in peritubular dentin (PTD) was revealed using Herovici stain and brightfield microscopy. Image analysis software and linear mixed modelling quantified outcomes. In situ dentin collagen was observed using Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM). The PSR-Pol analysis revealed less coherently aligned and more bundled collagen fibrils in aged dentin (P = 0.005). Deep inner dentin collagen in both groups were less coherently aligned with reduced bundling. Regardless of age, CLSM showed collagen distribution remained stable; and more collagen type III was detectable in PTD located in inner dentin (Young: P = 0.006; Aged: P = 0.008). Observations following Xe PFIB-SEM cross-sectioning showed apatite-like deposits surrounding large intratubular collagen fibers, and evidence of smaller intertubular dentin collagen fibrils in situ. In conclusion, aging changes collagen network architecture, but not distribution or content.
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Colágeno Tipo I , Microscopía , Humanos , DentinaRESUMEN
OBJECTIVE: To determine the effect of patient age (young or mature), anatomical location (shallow/deep and central/peripheral) and microscopic site (intertubular/peritubular) on dentine mineral density, distribution and composition. METHODS: Extracted posterior teeth from young (aged 19-20 years, N = 4) and mature (aged 54-77 years, N = 4) subjects were prepared to shallow and deep slices. The dentine surface elemental composition was investigated in a SEM using Backscattered Electron (BSE) micrographs, Energy Dispersive X-ray Spectroscopy, and Integrated Mineral Analysis. Qualitative comparisons and quantitative measures using machine learning were used to analyse the BSE images. Quantitative outcomes were compared using quantile or linear regression models with bootstrapping to account for the multiple measures per sample. Subsequently, a Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM) was used to mill large area (100 µm) cross-sections to investigate morphology through the dentine tubules using high resolution secondary electron micrographs. RESULTS: With age, dentine mineral composition remains stable, but density changes with anatomical location and microscopic site. Microscopically, accessory tubules spread into intertubular dentine (ITD) from the main tubule lumens. Within the lumens, mineral deposits form calcospherites in the young that eventually coalesce in mature tubules and branches. The mineral occlusion in mature dentine increases overall ITD density to reflect peritubular dentine (PTD) infiltrate. The ITD observed in micrographs remained consistent for age and observation plane to suggest tubule deposition affects overall dentine density. Mineral density depends on the relative distribution of PTD to ITD that varies with anatomical location. SIGNIFICANCE: Adhesive materials may interact differently within a tooth as well as in different age groups.
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In view of the need for aesthetics, restorations of teeth will typically be completed using tooth colored restorative materials. With the advent of biomimetic restorative materials, such as glass ionomer cements (GIC), much greater emphasis is now being placed on how well such materials can resist the challenge of acids that are present in foods and drinks, or gastric contents that are regurgitated. This laboratory study compared the dissolution and behavior of five GIC materials (GC Fuji® VII, GC Fuji® Bulk, GC Fuji® IX Fast, Fuji® IX Extra and GC Equia® Forte Fil) when exposed to three acids (citric acid, phosphoric acid and lactic acid), versus ultrapure deionized water, which was used as a control. Discs of each material GIC were submerged in solutions and percentage weight changes over time determined. Subsequently, the GIC materials were also placed as a part of standardized Class II sandwich restorations in bovine teeth (n = 20), and submerged in the solutions, and the extent of GIC dissolution and protection of the adjacent tooth was scored. Weight loss increased with time and with acid concentration. Overall, the most soluble material was GC Fuji® IX Extra, while GC Fuji® IX Fast and GC Fuji® Bulk were less soluble, and the least soluble material was GC Equia® Forte Fil. The most destructive solution for both the discs and for GIC restorations in teeth was 10% citric acid, while the least destructive acid was 0.1% lactic acid. The more recent GIC materials GC Fuji® Bulk and GC Equia® Forte Fil showed increased acid resistance over the older GIC materials, and this further justifies their use in open sandwich Class II restorations in more hostile environments.
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BACKGROUND: As glass ionomers have the ability to reload fluoride from outside sources, the aim was to compare the recharge pattern of six glass ionomer cements after exposure to fluoride. MATERIALS AND METHODS: Fuji VII, Fuji IX, Riva Pink, Riva Bleach, Ketac Fil and Fuji IX Extra were investigated. The fluoride-containing materials used were tooth paste and mouth wash (Colgate). Specimens of each material (n=15) were immersed separately in deionized water for 59 days. Then the samples of each material were divided into three groups of five each. Two groups were recharged for 2, 20 and 60 min daily during three consecutive weekly intervals and then no treatment for one week. The third group was used as control. Fluoride release measurements (µg/cm(2)/day) were made in every 24 h. One-way and repeated measures analysis of variance tests were used. RESULTS: Tooth paste recharged materials showed higher level of recharge. On day 1, the difference of fluoride release from different treatment groups of different materials except for Fuji IX Extra were not significant (P>0.05). On days 7 and 14, the differences observed were significant (P<0.05) for all materials except for Fuji VII (tooth paste versus mouth wash) and Trial Fuji IX (mouth wash versus control) and on day 14 for Rvia Pink (mouth wash versus control). On days 21 and 28, the differences observed were significant for all the materials (P<0.05) except for Riva Pink (toothpaste versus mouth wash), Riva Bleach, Ketac Fil and Trial FujiI X (mouth wash versus control) on day 28. CONCLUSION: A time tabled schedule of application of fluoride-containing materials could help to achieve high fluoride release.
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This study examined the effect of air abrasion and thermocycling on the adaptation and shear bond strength, of composite resin bonded to dentin using etch-and-rinse and self-etch resin adhesives. Confocal microscopy showed both adhesives closely adapted to dentin and a significantly (p<0.001) greater number of resin tags were observed for the etch-and-rinse adhesive. Air abrasion significantly increased resin tag length (p<0.05) for the etch-and-rinse adhesive and significantly increased the number (p<0.001), length (p<0.001) and thickness (p<0.01) of tags for the self-etch adhesive. However, air abrasion resulted in defect formation within the hybrid layer and thermocycling caused separation of the hybrid layer from adjacent dentin containing resin tags. A significant (p<0.05) reduction in shear bond strength was observed for the etch-and-rinse adhesive following thermocycling. Both adhesive systems adapted well to dentin in vitro and shear bond strengths were similar. The area of tag penetration into dentin was significantly (p<0.0001) enhanced following air abrasion.
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Grabado Ácido Dental/métodos , Abrasión Dental por Aire , Recubrimiento Dental Adhesivo , Análisis del Estrés Dental , Permeabilidad de la Dentina , Recubrimientos Dentinarios , Cementos de Resina , Bisfenol A Glicidil Metacrilato , Resinas Compuestas , Preparación de la Cavidad Dental , Dentina , Calor , Humanos , Microscopía Confocal , Resistencia al Corte , Propiedades de SuperficieRESUMEN
With a tube etching process, conical-ended optical fibers for middle infrared lasers that have lateral emissions can be produced, a feature of benefit for delivering laser energy onto the root canal walls. This study examined the ability of these improved laser tips when Er:YAG and Er,Cr:YSGG lasers were used in root canals in which thick smear layers had been created intentionally to provide a challenge for the laser system. Smear layer was assessed from scanning electron microscopy images with an objective digital method. Lasing improved the action of ethylene diamine tetraacetic acid with cetavlon (EDTAC) in removing smear layer. Conical fibers performed better than plain fibers, but there was no difference in performance between the 2 laser systems when matched for all other parameters. These results provide a "proof of concept" for lateral emitting fibers for endodontic procedures and illustrate the novel contribution of lasing to the action of EDTAC in dissolving smear layer.
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Cavidad Pulpar/efectos de los fármacos , Dentina/efectos de los fármacos , Láseres de Estado Sólido/uso terapéutico , Fibras Ópticas , Irrigantes del Conducto Radicular/efectos de la radiación , Capa de Barro Dentinario , Ápice del Diente/efectos de los fármacos , Cetrimonio , Compuestos de Cetrimonio/efectos de la radiación , Compuestos de Cetrimonio/uso terapéutico , Quelantes/efectos de la radiación , Quelantes/uso terapéutico , Cavidad Pulpar/ultraestructura , Dentina/ultraestructura , Ácido Edético/análogos & derivados , Ácido Edético/efectos de la radiación , Ácido Edético/uso terapéutico , Diseño de Equipo , Humanos , Peróxido de Hidrógeno/efectos de la radiación , Peróxido de Hidrógeno/uso terapéutico , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Irrigantes del Conducto Radicular/uso terapéutico , Preparación del Conducto Radicular/instrumentación , Preparación del Conducto Radicular/métodos , Hipoclorito de Sodio/efectos de la radiación , Hipoclorito de Sodio/uso terapéutico , Ápice del Diente/ultraestructuraRESUMEN
The incidence of tooth wear or non-carious tooth surface loss (NCTSL) is increasing and oral rehabilitation of patients with tooth tissue loss requires strategies that address all the factors relevant to the aetiology and pathogenesis of the disease. The multifactorial nature of the disease and the variability in its clinical presentation provides treatment challenges for the clinician. Management of tooth wear must be more than just restoration. Risk assessment, compliance and a commitment from both professional and patient underpin overall success of the treatment. Understanding that long term success is affected by the patient's oral environment and how diet, lifestyle and medical factors modify this environment. Improvements in the quantity and quality of saliva and remineralization strategies to enhance the remaining tooth structure are essential pre-restorative requirements. Successful management requires recognition of the problem, stabilization of the oral environment, remineralization of the tooth structure and when appropriate restoration.
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Restauración Dental Permanente/métodos , Abrasión de los Dientes/diagnóstico , Atrición Dental/diagnóstico , Erosión de los Dientes/diagnóstico , Adulto , Factores de Edad , Anciano , Tampones (Química) , Bebidas Gaseosas/efectos adversos , Cariostáticos/uso terapéutico , Caseínas/uso terapéutico , Conducta Alimentaria , Fluoruros/uso terapéutico , Humanos , Estilo de Vida , Persona de Mediana Edad , Higiene Bucal , Cooperación del Paciente , Medición de Riesgo , Saliva/fisiología , Abrasión de los Dientes/prevención & control , Abrasión de los Dientes/terapia , Atrición Dental/prevención & control , Atrición Dental/terapia , Desmineralización Dental/diagnóstico , Desmineralización Dental/prevención & control , Desmineralización Dental/terapia , Erosión de los Dientes/prevención & control , Erosión de los Dientes/terapia , Remineralización Dental , Resultado del TratamientoRESUMEN
A technique is presented for the use of a transparent polyvinyl siloxane template constructed from a diagnostic wax-up to rapidly reproduce the anatomical structure with direct restorative materials in the mouth. This technique is beneficial for a number of geriatric patients who would be unable to undertake long and complex dental treatment sessions and provides an alternative for those unable to meet the immediate costs of multiple indirect restorations. Consideration of increases in vertical dimension to create space for the new restorations and reconstruction utilizing a combination of direct and indirect procedures provides control and predictability over the final restorative result. In the short to medium term, the use of minimally invasive adhesive techniques enables tooth surface loss to be replaced with minimal destruction of the remaining sound tooth material, yet still enables the option for a more definitive restorative option at a later date.
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Restauración Dental Permanente/métodos , Abrasión de los Dientes/diagnóstico , Atrición Dental/diagnóstico , Erosión de los Dientes/diagnóstico , Grabado Ácido Dental , Cariostáticos/uso terapéutico , Caseínas/uso terapéutico , Resinas Compuestas/química , Coronas , Recubrimiento Dental Adhesivo , Materiales Dentales/química , Diseño de Prótesis Dental/instrumentación , Restauración Dental Permanente/instrumentación , Fluoruros/uso terapéutico , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Higiene Bucal , Planificación de Atención al Paciente , Polivinilos/química , Siloxanos/química , Propiedades de Superficie , Abrasión de los Dientes/terapia , Atrición Dental/terapia , Erosión de los Dientes/terapia , Preparación del Diente/métodos , Pastas de Dientes/uso terapéutico , Dimensión VerticalRESUMEN
PRIMARY OBJECTIVE: To extend the capabilities of current electropalatography (EPG) systems by developing a pressure-sensing EPG system. An initial trial of a prototype pressure-sensing palate will be presented. RESEARCH DESIGN: The processes involved in designing the pressure sensors are outlined, with Hall effect transistors being selected. These units are compact, offer high sensitivity and are inexpensive. An initial prototype acrylic palate was constructed with five embedded pressure sensors. Syllable repetitions were recorded from one adult female. MAIN OUTCOMES, RESULTS AND FUTURE DIRECTIONS: The pressure-sensing palate was capable of recording dynamic tongue-to-palate pressures, with minimal to no interference to speech detected perceptually. With a restricted number of sensors, problems were encountered in optimally positioning the sensors to detect the consonant lingual pressures. Further developments are planned for various aspects of the pressure-sensing system. CONCLUSIONS: Although only in the prototype stage, the pressure-sensing palate represents the new generation of EPG. Comprehensive analysis of tongue-to-palate contacts, including pressure measures, is expected to enable more specific and effective therapeutic techniques to be developed for a variety of speech disorders.
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Electrofisiología/instrumentación , Hueso Paladar/fisiopatología , Trastornos del Habla/diagnóstico , Trastornos del Habla/terapia , Lengua/fisiopatología , Adulto , Diseño de Equipo , Femenino , Humanos , PresiónRESUMEN
OBJECTIVES: This study examined the depth of cure and surface microhardness of Filtek Z250 composite resin (3M-Espe) (shades B1, A3, and C4) when cured with three commercially available light emitting diode (LED) curing lights [E-light (GC), Elipar Freelight (3M-ESPE), 475H (RF Lab Systems)], compared with a high intensity quartz tungsten halogen (HQTH) light (Kerr Demetron Optilux 501) and a conventional quartz tungsten halogen (QTH) lamp (Sirona S1 dental unit). METHODS: The effects of light source and resin shade were evaluated as independent variables. Depth of cure after 40 s of exposure was determined using the ISO 4049:2000 method, and Vickers hardness determined at 1.0 mm intervals. RESULTS: HQTH and QTH lamps gave the greatest depth of cure. The three LED lights showed similar performances across all parameters, and each unit exceeded the ISO standard for depth of cure except GC ELight for shade B1. In terms of shade, LED lights gave greater curing depths with A3 shade, while QTH and HQTH lights gave greater curing depths with C4 shade. Hardness at the resin surface was not significantly different between LED and conventional curing lights, however, below the surface, hardness reduced more rapidly for the LED lights, especially at depths beyond 3 mm. SIGNIFICANCE: Since the performance of the three LED lights meets the ISO standard for depth of cure, these systems appear suitable for routine clinical application for resin curing.