Search results for " abrasion"
showing 10 items of 13 documents
Release of copper-amended particles from micronized copper-pressure-treated wood during mechanical abrasion
2016
Background We investigated the particles released due to abrasion of wood surfaces pressure-treated with micronized copper azole (MCA) wood preservative and we gathered preliminary data on its in vitro cytotoxicity for lung cells. The data were compared with particles released after abrasion of untreated, water (0% MCA)-pressure-treated, chromated copper (CC)-pressure-treated wood, and varnished wood. Size, morphology, and composition of the released particles were analyzed. Results Our results indicate that the abrasion of MCA-pressure-treated wood does not cause an additional release of nanoparticles from the unreacted copper (Cu) carbonate nanoparticles from of the MCA formulation. Howev…
Retention strength of ball-attachment titanium post for removable partial denture or overdenture
2020
Aim: To evaluate the retention of an endodontic titanium post with a spherical head for removable partial denture or overdenture attachment according to surface treatment type. Methods: Sixty healthy single-rooted teeth, sectioned at the enamel/cementum junction, were treated endodontically and steadily fixed in the embedding acrylic resin. The titanium posts were subdivided into four groups: control, no surface treatment (Ctrl); posts with macro-retentive grooves (MR); air abrasion of the post surface (AB); and posts with macro-retentive grooves and air abrasion of the post surface (MR+AB). The posts were luted in the root canal using self-adhesive dual resin cement. Pull-out testing was p…
Effects Of COOH-terminal tripeptide alpha-MSH (11-13) on corneal epithelial wound healing:role of nitric oxide
2006
It is known that alpha-melanocyte stimulating hormone (alpha-MSH) may exert anti-inflammatory effects and facilitate reparative processes in different tissues. The effective message sequence of alpha-MSH resides in the COOH-terminal tripeptide alpha-MSH(11-13). This study was undertaken to investigate the effects of topical administration of the COOH-terminal tripeptide sequence of alpha-MSH (alpha-MSH(11-13), KPV) on corneal epithelial wound healing in rabbits and the possible role of nitric oxide (NO) in these effects. The whole corneal epithelium was denuded in both eyes by mechanical abrasion. The area of the corneal epithelial defect was stained with fluorescein, photographed, and then…
Species-specific enamel differences in hardness and abrasion resistance between the permanent incisors of cattle (Bos primigenius taurus) and the eve…
2022
Hypselodont (ever-growing) teeth of lagomorphs or rodents have higher wear rates (of a magnitude of mm/week), with compensating growth rates, compared to the non-ever-growing teeth of ungulates (with a magnitude of mm/year). Whether this is due to a fundamental difference in enamel hardness has not been investigated so far. We prepared enamel samples (n = 120 per species) from incisors of cattle (Bos primigenius taurus) and nutria (Myocastor coypus, hypselodont incisors) taken at slaughterhouses, and submitted them to indentation hardness testing. Subsequently, samples were split into 4 groups per species (n = 24 per species and group) that were assessed for abrasion susceptibility by a sta…
Pattern and rate of post-20 ka vertical tectonic motion around the Capo Vaticano Promontory (W Calabria, Italy) based on offshore geomorphological in…
2014
The magnitude and rate of Late Pleistocene-Holocene vertical tectonic movements offshore of the Capo Vaticano Promontory (western Calabria, southern Italy) have been measured on the basis of the present-day depth variations of the edges of submerged depositional terraces (and associated abrasion platforms) that formed below the storm-wave base, during the sea level stillstand of the Last Glacial Maximum (LGM). These depositional features, represented by submerged prograding wedges and an associated terrace-shaped upper boundary, have been identified in high-resolution seismic reflection profiles acquired along the continental shelf and the upper slope of the promontory, and are referred to …
Evaluation of retention of pit and fissure sealants placed with and without air abrasion pretreatment in 6-8 year old children – An in vivo study
2017
Background The success of pit and fissure sealants is directly related to their retention. The purpose of this study was to assess and compare the retention of pit and fissure sealants placed using acid etch alone and a combination of air abrasion and acid etch techniques. Material and Methods 50 subjects aged 6-8 years were included in the study. Primary second molars and permanent first molars were sealed in all four quadrants using split mouth design. The right maxillary and mandibular molars (Group A) were treated by acid etching alone while the left maxillary and mandibular molars (Group B) were pretreated with air abrasion followed by acid etching before application of pit and fissure…
Forage silica and water content control dental surface texture in guinea pigs and provide implications for dietary reconstruction.
2019
Significance Ingesta leave characteristic wear features on the tooth surface, which enable us to reconstruct the diet of extant and fossil vertebrates. However, whether dental wear is caused by internal (phytoliths) or external (mineral dust) silicate abrasives is controversially debated in paleoanthropology and biology. To assess this, we fed guinea pigs plant forages of increasing silica content (lucerne < grass < bamboo) without any external abrasives, both in fresh and dried state. Abrasiveness and enamel surface wear increased with higher forage phytolith content. Additionally, water loss altered plant material properties. Dental wear of fresh grass feeding was similar to lucerne brows…
The 3D modelling of musive surfaces for a monitoring protocol
2022
In questo lavoro l'utilizzo della metodologia digitale tridimensionale per la scansione di superfici musive è stato indagato nell'ambito dell'intervento di restauro di un mosaico pavimentale all'interno della Cappella Palatina di Palermo. Grazie alla possibilità di sezionare il modello di maglia con un software di rappresentazione digitale, è stato possibile confrontare la superficie della maglia con una superficie piana di riferimento allo scopo di valutare uno dei declini della posta dei pavimenti musivi, ovvero l'abrasione delle superfici In this paper the use of three-dimensional digital methodology for scanning musive surfaces was investigated within the restoration intervention on a f…
Shape, size, and quantity of ingested external abrasives influence dental microwear texture formation in guinea pigs
2020
Food processing wears down teeth, thus affecting tooth functionality and evolutionary success. Other than intrinsic silica phytoliths, extrinsic mineral dust/grit adhering to plants causes tooth wear in mammalian herbivores. Dental microwear texture analysis (DMTA) is widely applied to infer diet from microscopic dental wear traces. The relationship between external abrasives and dental microwear texture (DMT) formation remains elusive. Feeding experiments with sheep have shown negligible effects of dust-laden grass and browse, suggesting that intrinsic properties of plants are more important. Here, we explore the effect of clay- to sand-sized mineral abrasives (quartz, volcanic ash, loess,…
The effect of dentine pre-treatment using bioglass and/or polyacrylic acid on the interfacial characteristics of resin-modified glass ionomer cements.
2018
Objective To evaluate the effect of load-cycle aging and/or 6 months artificial saliva (AS) storage on bond durability and interfacial ultramorphology of resin-modified glass ionomer cement (RMGIC) applied to dentine air-abraded using Bioglass 45S5 (BAG) with/without polyacrylic acid (PAA) conditioning.Methods RMGIC (Ionolux, VOCO) was applied onto human dentine specimens prepared with silicon-carbide abrasive paper or air-abraded with BAG with or without the use of PAA conditioning. Half of bonded-teeth were submitted to load cycling (150,000 cycles) and half immersed in deionised water for 24 h. They were cut into matchsticks and submitted immediately to microtensile bond strength (μTBS) …