scholarly journals Post-mortem enamel surface texture alteration during taphonomic processes—do experimental approaches reflect natural phenomena?

PeerJ ◽  
2022 ◽  
Vol 10 ◽  
pp. e12635
Author(s):  
Katrin Weber ◽  
Daniela E. Winkler ◽  
Ellen Schulz-Kornas ◽  
Thomas M. Kaiser ◽  
Thomas Tütken
Keyword(s):  
Size Fraction ◽  
Fine Sand ◽  
Enamel Surface ◽  
Acid Etching ◽  
Post Mortem ◽  
Dental Microwear ◽  
Sediment Grain Size ◽  
Experimental Approaches ◽  
Dental Surface ◽  
Taphonomic Processes

Experimental approaches are often used to better understand the mechanisms behind and consequences of post-mortem alteration on proxies for diet reconstruction. Dental microwear texture analysis (DMTA) is such a dietary proxy, using dental wear features in extant and extinct taxa to reconstruct feeding behaviour and mechanical food properties. In fossil specimens especially, DMTA can be biased by post-mortem alteration caused by mechanical or chemical alteration of the enamel surface. Here we performed three different dental surface alteration experiments to assess the effect of common taphonomic processes by simplifying them: (1) tumbling in sediment suspension to simulate fluvial transport, (2) sandblasting to simulate mechanical erosion due to aeolian sediment transport, (3) acid etching to simulate chemical dissolution by stomach acid. For tumbling (1) we found alteration to be mainly dependent on sediment grain size fraction and that on specimens tumbled with sand fractions mainly post-mortem scratches formed on the dental surface, while specimens tumbled with a fine-gravel fraction showed post-mortem formed dales. Sandblasting (2) with loess caused only negligible alteration, however blasting with fine sand quartz particles resulted in significant destruction of enamel surfaces and formation of large post-mortem dales. Acid etching (3) using diluted hydrochloric acid solutions in concentrations similar to that of predator stomachs led to a complete etching of the whole dental surface, which did not resemble those of teeth recovered from owl pellets. The experiments resulted in post-mortem alteration comparable, but not identical to naturally occurring post-mortem alteration features. Nevertheless, this study serves as a first assessment and step towards further, more refined taphonomic experiments evaluating post-mortem alteration of dental microwear texture (DMT).

Dental microwear texture analysis on extant and extinct sharks: Ante- or post-mortem tooth wear?

2021 ◽  
Vol 562 ◽  
pp. 110147
Author(s):  
Katrin Weber ◽  
Daniela E. Winkler ◽  
Thomas M. Kaiser ◽  
Živilė Žigaitė ◽  
Thomas Tütken
Keyword(s):  
Texture Analysis ◽  
Tooth Wear ◽  
Post Mortem ◽  
Dental Microwear ◽  
Dental Microwear Texture Analysis

scholarly journals Enamel bonding of self-etching and phosphoric acid-etching orthodontic adhesives in simulated clinical conditions: Debonding force and enamel surface

2009 ◽  
Vol 28 (4) ◽  
pp. 419-425 ◽  
Author(s):  
Shinya HORIUCH ◽  
Kazuyuki KANEKO ◽  
Hiroko MORI ◽  
Emi KAWAKAMI ◽  
Takashi TSUKAHARA ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Enamel Surface ◽  
Acid Etching ◽  
Orthodontic Adhesives ◽  
Clinical Conditions ◽  
Phosphoric Acid Etching

Effects of Pretreatment Methods on the Enamel Surface Improving Sealant Adhesion

2019 ◽  
Vol 40 ◽  
pp. 92-100
Author(s):  
Adina Rotaru-Birgaoanu ◽  
Teodora Teslaru ◽  
R. Ionut Olariu ◽  
Ionut Chirap ◽  
Liliana Sachelarie ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Diffuse Reflectance ◽  
Enamel Surface ◽  
Acid Etching ◽  
Minimum Level ◽  
Angle Measurements ◽  
Physical Chemical ◽  
Contact Angle Measurements ◽  
Hydrophilic Character ◽  
Yellow Index

Is PlasBeam pretreatment an efficient method to improve sealant adhesion onto the enamel surface?The aim of this study isto investigate the effects induced by three pretreatment techniques used to improve sealant adhesion on the enamel surface, respectively standard acid-etching, UV radiations and a new method based on plasma operating at atmospheric pressure, namely the PlasBeam method.The physical-chemical modifications induced onto the enamel surface by the above pretreatments were analyzed using Contact Angle Measurements and Diffuse Reflectance Spectroscopy.The changes in the enamel surface morphology show that the acid-etching pretreatment is mostly efficient in increasing roughness, but this method stimulates the degradation processes that are well-known and turns down the brillianceof the treated surface. On the other hand, the PlasBeam treatment brings a higher roughness at the contact area between sealant and the enamel surface, compared to the UV radiations pretreatments.Moreover, the PlasBeam improves the hydrophilic character of enamel as a practical solution in enhancing the sealant adhesion to the surface. Related to other effects, it has been noticed that thePlasBeam method generates the most reflective enamel surface, whereas the White/Yellow index reaches the minimum level after a 10 second treatment.

scholarly journals Universal relation with regime transition for sediment transport in fine-grained rivers

2019 ◽  
Vol 117 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Hongbo Ma ◽  
Jeffrey A. Nittrouer ◽  
Baosheng Wu ◽  
Michael P. Lamb ◽  
Yuanfeng Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Sediment Load ◽  
Yellow River ◽  
Fine Sand ◽  
Sediment Flux ◽  
Universal Relation ◽  
Sediment Grain Size ◽  
Fine Grained ◽  
Predictive Algorithm ◽  
Sediment Size

Fine-grained sediment (grain size under 2,000 μm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 μm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

scholarly journals Diversity and distribution of crustaceans from 13 sheltered sandy beaches along São Sebastião Channel, south-eastern Brazil

2001 ◽  
Vol 81 (3) ◽  
pp. 475-484 ◽  
Author(s):  
P.R. Nucci ◽  
A. Turra ◽  
E.H. Morgado
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Clay Content ◽  
Fine Sand ◽  
Sandy Beaches ◽  
Matter Content ◽  
Sediment Grain Size ◽  
Crustacean Species ◽  
South Eastern ◽  
Eastern Brazil

The crustacean species composition in the intertidal zones of 13 sheltered unconsolidated marine beaches in south-eastern Brazil is described. Fifty-three crustacean species were collected, adding 46 species to the total reported by previous studies in the same region. Decapods dominated the community, in contrast to exposed sandy beaches where peracarids normally predominate. The species were distributed irregularly among the beaches. Richness varied markedly among sites, and was positively related to a combination of factors such as fine sand grains, high organic matter content, and relatively low silt–clay content. The presence of rock fragments enabled both rocky shore and sandy beach crustaceans to occur on the same beaches. Richness and abundance of crustaceans showed no clear relationship to sediment grain size and slope, in contrast to the norm for exposed sandy beaches. The dominance of the tanaid Kalliapseudes schubarti in some areas may be a result of organic matter pollution in the region. These beaches showed higher species richness than typical sheltered and exposed sandy beaches, indicating that this sheltered, highly heterogeneous seascape is an important area for conservation.

Effects of Pulsed Nd:YAG Laser on Tensile Bond Strength and Caries Resistance of Human Enamel

2014 ◽  
Vol 39 (3) ◽  
pp. 273-282 ◽  
Author(s):  
X Wen ◽  
L Zhang ◽  
R Liu ◽  
M Deng ◽  
Y Wang ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Bond Strength ◽  
Nd:Yag Laser ◽  
Acid Resistance ◽  
Enamel Surface ◽  
Acid Etching ◽  
Laser Parameter ◽  
Pulsed Nd:Yag Laser ◽  
Resistance Evaluation ◽  
Human Enamel

SUMMARY This study aims to evaluate the effects of pulsed Nd:YAG laser on the tensile bond strength (TBS) of resin to human enamel and caries resistance of human enamel. A total of 201 human premolars were used in this in vitro study. A flat enamel surface greater than 4 × 4 mm in area was prepared on each specimen using a low-speed cutting machine under a water coolant. Twenty-one specimens were divided into seven groups for morphology observations with no treatment, 35% phosphoric acid etching (30 seconds), and laser irradiation (30 seconds) of pulsed Nd:YAG laser with five different laser-parameter combinations. Another 100 specimens were used for TBS testing. They were embedded in self-cured acrylic resin and randomly divided into 10 groups. After enamel surface pretreatments according to the group design, resin was applied. The TBS values were tested using a universal testing machine. The other 80 specimens were randomly divided into eight groups for acid resistance evaluation. Scanning electron microscope (SEM) results showed that the enamel surfaces treated with 1.5 W/20 Hz and 2.0 W/20 Hz showed more etching-like appearance than those with other laser-parameter combinations. The laser-parameter combinations of 1.5 W/15 Hz and 1.5 W/20 Hz were found to be efficient for the TBS test. The mean TBS value of 14.45 ± 1.67 MPa in the laser irradiated group was significantly higher than that in the untreated group (3.48 ± 0.35 MPa) but lower than that in the 35% phosphoric acid group (21.50 ± 3.02 MPa). The highest mean TBS value of 26.64 ± 5.22 MPa was identified in the combination group (laser irradiation and then acid etching). Acid resistance evaluation showed that the pulsed Nd:YAG laser was efficient in preventing enamel demineralization. The SEM results of the fractured enamel surfaces, resin/enamel interfaces, and demineralization depths were consistent with those of the TBS test and the acid resistance evaluation. Pulsed Nd:YAG laser as an enamel surface pretreatment method presents a potential clinical application, especially for the caries-susceptible population or individuals with recently bleached teeth.

scholarly journals Etching Enamel for Orthodontics with an Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser System

2007 ◽  
Vol 77 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Güvenç Basaran ◽  
Törün Özer ◽  
Nükhet Berk ◽  
Orhan Hamamcı
Keyword(s):  
Bond Strength ◽  
Laser Irradiation ◽  
Shear Bond Strength ◽  
Laser System ◽  
Surface Characteristics ◽  
Enamel Surface ◽  
Acid Etching ◽  
Adhesive Remnant Index ◽  
Significant Difference ◽  
Power Outputs

Abstract Objective: To test the shear bond strength, surface characteristics, and fracture mode of brackets that are bonded to enamel etched with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser operated at different power outputs: 0.5 W, 1 W, and 2 W. Materials and Methods: Human premolars that had been extracted for orthodontic purposes were used. Enamel was etched with an Er,Cr:YSGG laser system operated at one of three power outputs or with orthophosphoric acid. Results: The shear bond strength associated with the 0.5-W laser irradiation was significantly less than the strengths obtained with the other irradiations. Both the 1-W and 2-W laser irradiations were capable of etching enamel in the same manner. This finding was confirmed by scanning electron microscopy examination. The evaluation of adhesive-remnant-index scores demonstrated no statistically significant difference in bond failure site among the groups, except for the 0.5-W laser–etched group. Generally, more adhesive was left on the enamel surface with laser irradiation than with acid etching. Conclusion: The mean shear bond strength and enamel surface etching obtained with an Er,Cr: YSGG laser (operated at 1 W or 2 W for 15 seconds) is comparable to that obtained with acid etching.

A new species of Polygordius (Polychaeta: Polygordiidae): from the inner continental shelf and in bays and harbours of the north-eastern United States

2006 ◽  
Vol 86 (5) ◽  
pp. 1025-1034 ◽  
Author(s):  
Patricia A. Ramey ◽  
Dieter Fiege ◽  
Brian S. Leander
Keyword(s):  
New Jersey ◽  
New Species ◽  
Continental Shelf ◽  
Rank Correlation ◽  
Fine Sand ◽  
Coarse Sand ◽  
Eastern United States ◽  
Sediment Grain Size ◽  
Inner Continental Shelf ◽  
A New Species

A new species of Polygordiidae, Polygordius jouinae sp. nov., along with its distribution, habitat, and reproduction is described. Polygordius jouinae sp. nov., the first North American Polygordius, is a dominant member of macrofaunal communities on the inner continental shelf, and in bays and harbours from Massachusetts to southern New Jersey. It is distinguished from most other Polygordius species by its non-inflated, heavily ciliated pygidium, absence of pygidial glands, and a conical (rather than rounded) prostomium. The 18S SSU rDNA from P. jouinae sp. nov. was sequenced and represents the first named Polygordius species with a DNA reference in GenBank. Spearman rank correlation of sediment grain size with density of P. jouinae sp. nov. at a New Jersey site showed that density was significantly (P<0.05; N=92) positively correlated with the proportion of medium to very coarse sand and negatively correlated with the fine sand fractions. Ecologically, P. jouinae sp. nov. is an important macrofaunal species given its widespread distribution and its fidelity for coarse sand habitats. Thus, its relative abundance may be useful as an indicator of changing sedimentary conditions.

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