High-elevation environments present harsh challenges for the pursuit of agropastoral subsistence strategies and relatively little is known about the mechanisms early communities employed to adapt to such locations successfully. This article presents the sequential carbon and oxygen analysis of archaeological caprine teeth from Bangga (c. 3000–2200 BP), which is approximately 3750masl on the Tibetan Plateau. Made visible through this method, intra-tooth variation in isotopic composition allows insights into herding strategies that possibly included the provisioning of livestock with groundwater and agricultural fodder and summer grazing in saline or marsh environments. Such intensive provisioning differs markedly from lower-elevation agropastoralism.

The presence of Roman material in early Anglo-Saxon graves in England is well documented, and recent excavations at Scremby in Lincolnshire have revealed a complete copper-alloy enamelled drinking cup in a sixth-century ad female burial. Not only is such a Roman vessel a very rare find, but also its inclusion in an early medieval grave makes it a unique example of the reuse of an antique object in a funerary context. This article presents a typological and metallurgical analysis of the cup and selected comparative examples from England and France are discussed. The context of deposition and the role the cup played as a burial container for animal fat are examined, as are the mechanisms that lay behind the cup's continued life several centuries after its manufacture.

The position of the Banwell Bone Cave mammal assemblage zone (MAZ) in the mammalian biostratigraphy of the British Isles has been the focus of debate for decades. Dominated by fauna typical of cold environments it was originally linked to the marine oxygen isotope stage (MIS) 4 stadial (ca. 72–59 ka). Subsequently it was argued that the Banwell Bone Cave MAZ more likely relates to the temperate interstadial of MIS 5a (ca. 86–72 ka). It is envisioned that “cold fauna” such as bison and reindeer moved into Britain during stadial MIS 5b (ca. 90 ka) and were subsequently isolated by the rising sea level during MIS 5a. Here we investigate environmental conditions during the Banwell Bone Cave MAZ using bone collagen δ13C and δ15N and tooth enamel δ18O and δ13C isotope analysis. We analyse bison and reindeer from the MAZ type-site, Banwell Bone Cave. Our results show unusually high δ15N values, which we ascribe to arid conditions within a temperate environment. Palaeotemperature estimates derived from enamel δ18O indicate warm temperatures, similar to present day. These results confirm that the Banwell Bone Cave MAZ relates to a temperate interstadial and supports its correlation to MIS 5a rather than MIS 4.

The mineral component (at least 95 wt. %) of dental enamel is hydroxyapatite (hydroxylapatite) with multiple substitutions. The biogenic origin of enamel is reflected in the unusual ribbon-like morphology of the crystals, which are extremely elongated in the c-axis direction, and their organized arrangement within the tissue. The study of enamel dissolution has been driven by the very high prevalence of dental caries. In enamel caries, the initial demineralization results in subsurface dissolution of mineral. While the surface remains intact, reversal of the lesion by remineralization is possible. Problems of understanding the physico-chemical processes in enamel demineralization include the general problems concerning the structure and chemistry of apatites formed in aqueous media. Added to these are the general problem of dissolution in an inhomogeneous porous medium and the complication that enamel apatite has a naturally variable composition which changes during demineralization. The use of model systems in caries research is illustrated by reference to X-ray absorption studies of enamel and synthetic analogues.

The enormous prestige accorded to Byzantine cloisonné enamel seems to have continued into the Palaiologan period, although evidence suggests that its production ceased in the decades after the Fourth Crusade. The medium of the imperial images described by Pseudo-Kodinos as ὑπὸ ὑελίου λεγομένου διαγελάστου, which was worn on the headgear of thirteen ranks of court officials, is here identified as verre églomisé, reverse painting on glass. A reading of Pseudo-Kodinos’ treatise alongside surviving works of art suggests that fourteenth-century Byzantines were consciously using ersatz media in an effort to keep up the appearance of continuity with the empire's more prosperous past.

Mammoth (Mammuthus sp.) teeth are relatively abundant in Quaternary deposits from Eurasia and North America, and their isotopic compositions can be used to reconstruct past seasonal patterns in precipitation, diet, and migration. Strategies for collecting and interpreting such data, however, are strongly dependent on growth rates, which can vary among species, individuals, and within teeth. In this study, we use histological and isotopic measurements to determine enamel growth rates for a Columbian mammoth (Mammuthus columbi) tooth in two directions. Using histology, the growth rate through the enamel thickness (ET; perpendicular to the height of the tooth) is estimated at 0.8 to 1.5 mm/yr. Isotopic sampling through the innermost 0.36 mm of the ET recovered less than half a period of variation (i.e., half an inferred year of growth), which is consistent with the histological estimate for ET growth rate. A combination of histological and isotopic measurements suggests that the enamel extension rate (growth in the height of the tooth) is 13–14 mm/yr. Knowledge of enamel growth rates should improve the design and interpretation of future isotopic studies of mammoth teeth. The combination of histological and isotopic measurements may also prove useful in determining growth rates for other extinct taxa.

We used analyses of the strontium isotope (87Sr/86Sr) ratios of tooth enamel to reconstruct the migration patterns of fossil mammals collected along the Aucilla River in northern Florida. Specimens date to the late-glacial period and before the last glacial maximum (pre-LGM). Deer and tapir displayed low 87Sr/86Sr ratios that were similar to the ratios of Florida environments, which suggest that these taxa did not migrate long distance outside of the Florida region. Mastodons, mammoths, and equids all displayed a wide range of 87Sr/86Sr ratios. Some individuals in each taxon displayed low 87Sr/86Sr ratios that suggest they ranged locally, while other animals had high 87Sr/86Sr ratios that suggest they migrated long distances (> 150 km) outside of the Florida region. Mastodons were the only taxa from this region that provided enough well-dated specimens to compare changes in migration patterns over time. Pre-LGM mastodons displayed significantly lower 87Sr/86Sr ratios than late-glacial mastodons, which suggests that late-glacial mastodons from Florida migrated longer distances than their earlier counterparts. This change in movement patterns reflects temporal changes in regional vegetation patterns.

Previous work in the San Luis Valley of south-central Colorado and northern New Mexico at the Hansen Bluff and SAM Cave localities has allowed reconstruction of the paleoclimate in the region during the interval from ∼0.6 myr to ∼2.6 myr. Surface exposures at Hansen Bluff have been correlated to deep-sea oxygen isotope core stages 18–23 and one of the glacial periods contained therein to the oldest “Nebraskan” till in southwestern Iowa. Deposits in SAM Cave correlate to Hansen Bluff on the basis of paleomagnetics, climate interpretation, and microtine rodent biochronology. In this paper, carbon and oxygen stable isotope data of herbivorous rodent teeth are used as indicators of change in the predominance of C3, C4, and CAM plants and of changes in temperature and precipitation. Taken together with other previously analyzed data from these localities, the evidence indicates a shift in the severity of glacial events that is mainly related to the hydrologic characteristics of the climate. This shift may have been caused by broad regional uplift that may have been instrumental in shifting global climate cycles from the 41,000-yr Matuyama cycles to the Brunhes 100,000-yr-dominated cycles.

The aim of this study was to compare surface structures of laser-irradiated dental hard tissues using confocal (CFM), atomic force (AFM), and scanning electron microscopy (SEM). The general potential of the AFM in analyzing laser-irradiated surfaces was determined in this context. Specimens of human enamel and dentin were irradiated using an 8.6 W Nd:YVO4 laser with a pulse duration of 8 ps, λCenter=1,064 nm, and a pulse repetition rate of 500 kHz. Surface topology of irradiated areas (1 mm2) was investigated using AFM, CFM, and SEM. Surface roughness Rz was measured only with the AFM and the CFM. For non-irradiated enamel and dentin surfaces, roughnesses for CFM and AFM are in the nanometer range. However, major differences in roughness were determined for laser-prepared surfaces. For enamel, Rz(CFM)=2.33 μm is much higher compared with Rz(AFM)=0.09 μm; in the case of dentin, Rz(CFM)=5.35 μm is also much higher compared with Rz(AFM)=0.093 μm. Information regarding structural properties of surfaces needs real dimensions, particularly for use in dentistry. In this respect, AFM technology provides no additional results that lead to a significant improvement.

The aim of the present work was to investigate birefringence and morphology of the secretory-stage enamel organic extracellular matrix (EOECM), and structural and mechanical properties of mature enamel of upper incisors from adult rats that had been treated with pamidronate disodium (0.5 mg/kg/week for 56 days), using transmitted polarizing and bright-field light microscopies (TPLM and BFLM), energy-dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM) and microhardness testing. BFLM showed no morphological changes of the EOECM in pamidronate and control groups, but TPLM revealed a statistically significant reduction in optical retardation values of birefringence brightness of pamidronate-treated rats when compared with control animals (p<0.01). EDX analysis showed that pamidronate-induced statistically significant decrease in phosphorus’ quantity in outer mature enamel (p<0.01) and an increase in the calcium/phosphorus ratio in that structure (p<0.05). Pamidronate did not induce ultra-structural alterations in mature enamel as revealed by SEM and did not cause a reduction in its microhardness (p>0.05). The present study indicates that pamidronate can affect birefringence of the secretory-stage EOECM, which does not seem to be associated with significant changes in morphological and/or mechanical properties of mature enamel.

By using strontium isotopic ratios of dental enamel from molars, we were able to reconstruct the migration context for three individuals of a Columbian mammoth population (Mammuthus columbi) around Laguna de las Cruces, San Luis Potosí, central México. A three-step leaching procedure was applied to eliminate secondary Sr contributions in the molar enamel. One of the studied individuals showed 87Sr/86Sr ratios similar to those obtained from soils and plants from Laguna de las Cruces and was identified as local, whereas the other two mammoths had different molar 87Sr/86Sr values, indicative of migration and mobility contexts.

Molar incisor hypomineralization (MIH) is a developmental disturbance of the enamel. This study presents analyses of hypomineralized and normal enamel in first molar teeth diagnosed with MIH, utilizing time-of-flight secondary ion mass spectrometry area analyses and X-ray microanalysis of area and spot profiles in uncoated samples between gold lines which provide electrical conductivity. Statistical analysis of mean values allows discrimination of normal from MIH enamel, which has higher Mg and lower Na and P. Inductive analysis using complete data sets for profiles from the enamel surface to the enamel–dentin junction found that Mg, Cl and position in the profile provide useful discrimination criteria. Element profiles provide a visual complement to the inductive analysis and several elements also provide insight into the development of both normal and MIH enamel. The higher Mg content and different Cl profiles of hypomineralized enamel compared with normal enamel are probably related to a relatively short period during the development of ameloblasts between birth and the 1st year of life.

Elemental analysis of dental hard tissues is of importance. The aim of this study is to evaluate X-ray microanalysis (XRMA) of bovine enamel in a scanning electron microscope (SEM) with different coatings. The buccal surface of bovine incisors was polished flat, one-third was coated with carbon, one-third with gold, leaving one-third uncoated for XRMA in an SEM equipped with an energy-dispersive microanalysis system. The elements oxygen, sodium, magnesium, phosphorous, chlorine, potassium, and calcium were analyzed using their respective characteristic K X-ray series. Comparisons were made with analyses of glass produced by fusion of the bovine enamel, showing that oxygen analyses using the K X-ray series are reliable and preferable to calculating oxygen by stoichiometry for natural enamel. For the gold-coated and uncoated analyses, carbon was also measured using the K X-ray series. Small area Analyses in small areas (80 × 80 μm) in variable pressure-SEM mode with low vacuum (20 Pa), without any coating, midway between 40 μm wide gold lines 140 μm apart to avoid build-up of electrostatic charge is the preferred method, especially if carbon is included in the analysis. The analyses of bovine enamel are sufficiently reproducible to be regarded as quantitative for all elements except carbon.

Enamel is the most visible tissue of the tooth. It gives the tooth its whiteness, its brilliance and is the main focus of our attention from an esthetic point of view. Unfortunately, it is not uncommon to see alterations in this enamel, whether they are simple localized discolored spots, or more extensive loss of tooth substance. The etiologies, then, are multiple: toxicity during the mineralization of the bud, hyperthermia or a genetic abnormality. As professionals, making an etiological diagnosis and reassuring the parents is a challenge that we must address on a daily basis.

Considerable debate persists concerning the origins of those involved in the adventus Saxonum: the arrival of Germanic peoples in Britain during the fifth century AD. This question was investigated using oxygen and strontium isotope ratios obtained from archaeological dental samples from individuals in the ‘Migration Period’ cemetery, Ringlemere, Kent (n = 7) and three continental European sites (n = 17). Results demonstrated that strontium alone is unable to distinguish between individuals from south-east England and north-west Europe. Although 87Sr/86Sr values from Ringlemere fell within local biosphere parameters and suggest a spatially and temporally related group, δ18O values were inconsistent with origins in eastern England or on the North German plain. Results from the European sites negate past climate change as an explanation. It is possible that culturally mediated behaviour has obscured geographical relationships. Further work to characterize water sources and human δ18O values in the putative European homelands is required.

The enamel of 20 Email Champlevé objects dating between the 12th and 19th centuries was investigated by means of microscopic and portable X-ray fluorescence analysis (μ-XRF and PXRF). Seven of these objects were microsampled and the fragments were analyzed with electron probe microanalysis (EPMA) and vacuum μ-XRF to obtain quantitative data about the composition of the glass used to produce these enameled objects. As a result of the evolution of the raw materials employed to produce the base glass, three different compositional groups could be discriminated. The first group consisted of soda-lime-silica glass with a sodium source of mineral origin (with low K content) that was opacified by addition of calcium antimonate crystals. This type of glass was only used in objects made in the 12th century. Email Champlevé objects from the beginning of the 13th century onward were enameled with soda-lime-silica glass with a sodium source of vegetal origin. This type of glass, which has a higher potassium content, was opacified with SnO2 crystals. The glass used for 19th century Email Champlevé artifacts was produced with synthetic and purified components resulting in a different chemical composition compared to the other groups. Although the four analytical techniques employed in this study have their own specific characteristics, they were all found to be suitable for classifying the objects into the different chronological categories.

This article reports our study, carried out as a CECSMO assignment, assessing the effectiveness of resin modified glass ionomer cement as a bonding agent on enamel over a two year period and a consideration of the relative influence of two brands of attachments, Orthos and Damon. In our study group we had an overall rate of bonding rupture of 11.6%. 17% of direct and 33% of the indirect bondings loosened in the first trimester. Globally, the direct bonding had a higher survival rate, which was, after one year, 95.2% for the direct bonding and 90.7% for the indirect. The survival rate of attachments bonded to second molars was the lowest for all the teeth in the arch with Damon Indirect recorded at .889 after a year and Orthos Indirect .524 after a year. We categorized our results in relation to the characteristics of our sample (its size, its heterogeneity, and the duration of the observation period) and in relation to the characteristics of the attachments (their size and the surface and type of their bases) and in relation to the protocols (of indirect bonding, of preparation of enamel surface, of photopolymerization, of placement of the first arch, of bracket size, of ligature placement, and type of mechano-therapy used).

Our study confirmed the hypothesis that direct or indirect bonding with Fuji Ortho LC@ functions effectively in the daily practice of orthodontics. Our rates of accidental attachment debonding and our rates of bonding survival were acceptable except in Orthos indirect bonding of mandibular teeth. We found that under the conditions of our study direct bonding functioned slightly better than indirect bonding. Practitioners need to know and understand certain parameters influencing the use of resin modified glass-ionomer cement for bonding orthodontic attachments in order to optimize its success notable with regard to the choice of attachments with respect to bonding material or the effect of overbite on retention of attachments. Furthermore, the multiplicity of interfaces and of materials utilized in indirect bonding weakened bond strength under the conditions and protocols of our study.

Dental remineralization may be achieved by mediating the interactions between tooth surfaces with free ions and biomimetic peptides. We recently developed octuplet repeats of aspartate-serine-serine (DSS-8) peptide, which occurs in high abundance in naturally occurring proteins that are critical for tooth remineralization. In this paper, we evaluated the possible role of DSS-8 in enamel remineralization. Human enamel specimens were demineralized, exposed briefly to DSS-8 solution, and then exposed to concentrated ionic solutions that favor remineralization. Enamel nano-mechanical behaviors, hardness and elastic modulus, at various stages of treatment were determined by nanoindentation. The phase, microstructure and morphology of the resultant surfaces were characterized using the grazing incidence X-ray diffraction (GIXD), variable pressure scanning electron microscopy (VPSEM), and atomic force microscopy (AFM), respectively. Nanoindentation results show that the DSS-8 remineralization effectively improves the mechanical and elastic properties for demineralized enamel.

The colonisation of the North Atlantic from the eighth century AD was the earliest expansion of European populations to the west. Norse and Celtic voyagers are recorded as reaching and settling in Iceland, Greenland and easternmost North America between c. AD 750 and 1000, but the date of these events and the homeland of the colonists are subjects of some debate. In this project, the birthplaces of 90 early burials from Iceland were sought using strontium isotope analysis. At least nine, and probably thirteen, of these individuals can be distinguished as migrants to Iceland from other places. In addition, there are clear differences to be seen in the diets of the local Icelandic peoples, ranging from largely terrestrial to largely marine consumption.

Since in vitro and animal studies suggest that the combination of starch with sucrose may be more cariogenic than sucrose alone, the study assessed in situ the effects of this association applied in vitro on the acidogenicity, biochemical and microbiological composition of dental biofilm, as well as on enamel demineralization. During two phases of 14 d each, fifteen volunteers wore palatal appliances containing blocks of human deciduous enamel, which were extra-orally submitted to four groups of treatments: water (negative control, T1); 2 % starch (T2); 10 % sucrose (T3); and 2 % starch+10 % sucrose (T4). The solutions were dripped onto the blocks eight times per day. The biofilm formed on the blocks was analysed with regard to amylase activity, acidogenicity, and biochemical and microbiological composition. Demineralization was determined on enamel by cross-sectional microhardness. The greatest mineral loss was observed for the association starch+sucrose (P<0·05). Also, this association resulted in the highest lactobacillus count in the biofilm formed (P<0·05). In conclusion, the findings suggest that a small amount of added starch increases the cariogenic potential of sucrose.