Studies of Peculiar Mg-Containing and Oscillating Bioapatites in Sheep and Horse Teeth.

New types of biological apatites have been discovered in molar sheep and horse teeth and are divided in two types. In the first and more general type, the release of Mg ions is parallel to the changes in composition of apatite leading to a final stoichiometric ratio of Ca to P ions, going from dentin depth towards the boundary of enamel with air. Inside dentin, another apatite sub-types were discovered with alternating layers of Mg-rich and C-rich apatites. The approximate formal stoichiometric relationships for these peculiar types of bioapatites are suggested. We identified two kinds of ion-exchanges responsible for formation of peculiar apatites. Various combinations of main and minor elements lead to new versions of biological apatites.

[Determination of Allyl Isothiocyanate in Mustard and Horseradish Extracts by Single Reference GC and HPLC Based on Relative Molar Sensitivities].

The main component of the Mustard and Horseradish extracts, which are used as natural food additives in Japan, is allyl isothiocyanate (AITC). The determination of AITC using GC-FID is the official method employed in the quality control assessments for these products. In this method, a commercially available AITC reagent is used as a calibrant. However, 1H-quantitative NMR (qNMR) analysis revealed that the AITC reagents contain impurity. Therefore, we examined the GC-FID and HPLC-refractive index detector (LC-RID) method based on relative molar sensitivities (RMSs) to high-purity single reference (SR). The RMSs of AITC/SR under the GC-FID and LC-RID conditions were accurately determined using qNMR. The AITC in two types of food additives was quantified using qNMR, SR GC-FID, and SR LC-RID methods. Both SR GC-FID and SR LC-RID showed good agreement within 2% with the AITC content determined by direct qNMR.

The effect of hydrochloric acid (HCl) on permanent molars: A scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) study.

It is well established that acid disposal is a potentially effective method used by criminal syndicates to hinder the identification of victims. This study documents the effects of continuous immersion in hydrochloric acid (HCl, 37%) on molars using macroscopic analysis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The goal of this study is to aid in distinguishing visually unrecognizable fragments of dental remains when drastic changes in morphology have occurred as a result of acid exposure. Macroscopic, SEM, and EDS analysis were conducted on seven maxillary molars before and after HCl treatment. Molars reduced in weight relative to the length of time immersed in HCl and the dissolution time was over 40 hours longer than reported in previous studies, at just over 66 hours. SEM and EDS analysis showed acid-treated teeth exhibited morphological patterns such as cracking and layering visible at high magnification. Calcium/phosphorous ratios fell within the expected range of 1.6-2.5, indicating that HCl-treated teeth are still identifiable as osseous or dental tissue even when not visually identifiable as teeth. This is the first study to present SEM images of molar cementum before and after immersion in HCl and to present EDS results. This information can assist researchers and investigators in determining the presence of dental tissue in a forensic context associated with acid disposal.

Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment.

Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962-2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River. There was little variation of total mercury (THg) in fish assemblages basin-wide and only 13% (272/1959) of individual fish samples exceeded the fish health benchmark (0.27 µg THg/g ww). Most THg exceedances were observed in the White-Yampa tributary whereas the San Juan had the lowest mean THg concentration. Risks associated with THg are species specific with exceedances dominated by Colorado Pikeminnow (mean = 0.38 and standard error ± 0.08 µg THg/g ww) and Roundtail Chub (0.24 ± 0.06 µg THg/g ww). For Se, 48% (827/1720) of all individuals exceeded the fish health benchmark (5.1 µg Se/g dw). The Gunnison river had the most individual exceedances of the Se benchmark (74%) whereas the Dirty Devil had the fewest. We identified that species of management concern accumulate THg and Se to levels above risk thresholds and that fishes of the White-Yampa (THg) and Gunnison (Se) rivers are at the greatest risk in the UCRB.

Laser Photobiomodulation Over Teeth Subjected to Orthodontic Movement.

Background: Orthodontics of the 21st century requires aesthetic, painless, predictable, and quick treatments. This demand for faster results generated orthodontic movement acceleration protocols (OMAPs); among other OMAPs we present low-level laser (LLL) as a candidate. Objective: To evaluate levels of interleukin (IL)-1, IL-10, and type 1 collagen in the periodontal ligament of first molars of rats subjected to orthodontic traction with and without LLL irradiation, compared with untreated controls (CO), and to evaluate whether the dose of LLL used in this work is eligible as an OMAP. Materials and methods: A total of 35 male Wistar rats were distributed into three groups: group 1 NI (nonirradiated) n = 15, group 2 IR (laser irradiated using 5 J, 177 J/cm2, and 100 mW applied in contact to the vestibular mesial, vestibular distal, and palatal faces of gum tissue around molar region for 50 sec each point, for 3 consecutive days, immediately 24 and 48 h after orthodontic device placement.) n = 15, and group 3 CO n = 5; groups 1 and 2 were subjected to orthodontic force and each group was divided into three subgroups that were sacrificed after 3, 5, and 7 days, IL-1/10 and COL-1 levels were analyzed. Results: In the IR group, levels of IL-1/10 and COL-1 showed peak anticipation after LLL irradiation compared with those in the NI and CO groups. Conclusions: These results can also infer that this dose of LLL can be used as an OMAP.

Land use and mobility during the Neolithic in Wales explored using isotope analysis of tooth enamel.

OBJECTIVES: The nature of land use and mobility during the transition to agriculture has often been debated. Here, we use isotope analysis of tooth enamel from human populations buried in two different Neolithic burial monuments, Penywyrlod and Ty Isaf, in south-east Wales, to examine patterns of land use and to evaluate where individuals obtained their childhood diet. MATERIALS AND METHODS: We employ strontium (87 Sr/86 Sr) and oxygen (δ18 O) and carbon (δ13 C) isotope analysis of enamel from adjacent molars. We compare strontium isotope values measured in enamel to locally bioavailable 87 Sr/86 Sr values. We combine discussion of these results with evaluation of new radiocarbon dates obtained from both sites. RESULTS: The majority of enamel samples from Penywyrlod have strontium isotope ratios above 0.7140. In contrast, the majority of those from Ty Isaf have 87 Sr/86 Sr values below 0.7140. At Penywyrlod oxygen isotope ratios range between 25.9 and 28.2 ‰ (mean 26.7 ± 0.6 ‰, 1σ, n = 15) and enamel δ13 Ccarbonate values range between -18.0 and -15.0 ‰ (mean -16.0 ± 0.8 ‰, 1σ, n = 15). At Ty Isaf oxygen isotope ratios exhibited by Neolithic individuals range between 25.4 and 27.7 ‰ (mean 26.7 ± 0.6 ‰, 1σ, n = 15) and enamel δ13 Ccarbonate values range between -16.9 and -14.9 ‰ (mean -16.0 ± 0.6 ‰, 1σ, n = 15). DISCUSSION: The strontium isotope results suggest that the majority of individuals buried at Penywyrlod did not source their childhood diet locally. One individual in this group has strontium isotope ratios that exceed all current known biosphere values within England and Wales. This individual is radiocarbon dated to the first few centuries of the 4th millennium BC, consistent with the period in which agriculture was initiated in Wales: the results therefore provide evidence for migration during the transition to farming in Wales. In contrast, all individuals sampled from Ty Isaf post-date the period in which agriculture is considered to have been initiated and could have sourced their childhood diet from the local region in which they were buried.

Plasmodium falciparum malaria in 1st-2nd century CE southern Italy.

The historical record attests to the devastation malaria exacted on ancient civilizations, particularly the Roman Empire [1]. However, evidence for the presence of malaria during the Imperial period in Italy (1st-5th century CE) is based on indirect sources, such as historical, epigraphic, or skeletal evidence. Although these sources are crucial for revealing the context of this disease, they cannot establish the causative species of Plasmodium. Importantly, definitive evidence for the presence of malaria is now possible through the implementation of ancient DNA technology. As malaria is presumed to have been at its zenith during the Imperial period [1], we selected first or second molars from 58 adults from three cemeteries from this time: Isola Sacra (associated with Portus Romae, 1st-3rd century CE), Velia (1st-2nd century CE), and Vagnari (1st-4th century CE). We performed hybridization capture using baits designed from the mitochondrial (mtDNA) genomes of Plasmodium spp. on a prioritized subset of 11 adults (informed by metagenomic sequencing). The mtDNA sequences generated provided compelling phylogenetic evidence for the presence of P. falciparum in two individuals. This is the first genomic data directly implicating P. falciparum in Imperial period southern Italy in adults.

Enamel alteration following tooth bleaching and remineralization.

The purpose of this study was to compare the effects of professional tooth whitening agents containing highly concentrated hydrogen peroxide (with and without laser activation), on the enamel surface; and the potential of four different toothpastes to remineralize any alterations. The study was performed on 50 human molars, divided in two groups: treated with Opalescence(®) Boost and Mirawhite(®) Laser Bleaching. Furthermore, each group was divided into five subgroups, a control one and 4 subgroups remineralized with: Mirasensitive(®) hap+, Mirawhite(®) Gelleѐ, GC Tooth Mousse™ and Mirafluor(®) C. The samples were analysed by SEM/3D-SEM-micrographs, SEM/EDX-qualitative analysis and SEM/EDX-semiquantitative analysis. The microphotographs show that both types of bleaching cause alterations: emphasized perikymata, erosions, loss of interprizmatic substance; the laser treatment is more aggressive and loss of integrity of the enamel is determined by shearing off the enamel rods. In all samples undergoing remineralization deposits were observed, those of toothpastes based on calcium phosphate technologies seem to merge with each other and cover almost the entire surface of the enamel. Loss of integrity and minerals were detected only in the line-scans of the sample remineralized with GC Tooth Mousse™. The semiquantitative EDX analysis of individual elements in the surface layer of the enamel indicates that during tooth-bleaching with HP statistically significant loss of Na and Mg occurs, whereas the bleaching in combination with a laser leads to statistically significant loss of Ca and P. The results undoubtedly confirm that teeth whitening procedures lead to enamel alterations. In this context, it must be noted that laser bleaching is more aggressive for dental substances. However, these changes are reversible and can be repaired by application of remineralization toothpastes.

Clinical, mineral and ultrastructural changes in carious dentin of primary molars after restoration.

INTRODUCTION: Partial caries removal has been shown to be an effective method to treat deep carious lesions in deciduous teeth. Nevertheless, the possibility of keeping infected dentin in the cavity still requires additional investigation. The objective of this research was to describe changes in primary infected dentin after restoration with glass ionomer cement. METHODS: Dentin from 45 primary molars with deep and active carious lesions was evaluated using clinical and laboratory criteria, before and 60 days after restoration. The clinical analysis evaluated dentin colour (CO), dentin consistency (COS) and laser fluorescence (LF). The laboratory procedures assessed bacterial contamination and mineral content (MC), and evaluated the dentin ultrastructure and collagen content. Data on CO, COS, LF and colony forming units were analysed using the Wilcoxon signed-rank test; MC, bacterial counts and collagen evaluations were evaluated using the Student's t-test. RESULTS: After 60 days, lower values of LF were observed, together with a lower bacterial count, and a higher COS was found, with an increase in calcium, phosphorus and collagen contents. Differences were not detected for CO or for fluorine content. Baseline samples showed enlarged tubules with bacterial invasion; 60-day samples showed better organised tissue, with a more compact intertubular dentin and narrower tubules. CONCLUSION: It is concluded that appropriate cavity sealing can promote beneficial changes in deep carious lesions of primary teeth, even in the presence of infected dentin.

The effect of air-abrasion on the susceptibility of sound enamel to acid challenge.

OBJECTIVE: To evaluate the effect of air-abrasion using three abrasive powders, on the susceptibility of sound enamel to an acid challenge. METHODS: 40 human enamel samples were flattened, polished and assigned to 4 experimental groups (n=10); a: alumina air-abrasion, b: sodium bicarbonate air-abrasion, c: bioactive glass (BAG) air-abrasion and d: no surface treatment (control). White light confocal profilometry was used to measure the step height enamel loss of the abraded area within each sample at three stages; after sample preparation (baseline), after air-abrasion and finally after exposing the samples to pH-cycling for 10 days. Data was analysed statistically using one-way ANOVA with Tukey's HSD post-hoc tests (p<0.05). Unique prismatic structures generated by abrasion and subsequent pH cycling were imaged using multiphoton excitation microscopy, exploiting strong autofluorescence properties of the enamel without labelling. Z-stacks of treated and equivalent control surfaces were used to generate non-destructively 3-dimensional surface profiles similar to those produced by scanning electron microscopy. RESULTS: There was no significant difference in the step height enamel loss after initial surface air-abrasion compared to the negative control group. However, a significant increase in the step height enamel loss was observed in the alumina air-abraded samples after pH-cycling compared to the negative control (p<0.05). Sodium bicarbonate as well as BAG air-abrasion exhibited similar enamel surface loss to that detected in the negative control group (p>0.05). Surface profile examination revealed a deposition effect across sodium bicarbonate and BAG-abraded groups. CONCLUSION: This study demonstrates the importance of powder selection when using air abrasion technology in clinical dentistry. Pre-treating the enamel surface with alumina air-abrasion significantly increased its susceptibility to acid challenge. Therefore, when using alumina air-abrasion clinically, clinicians must be aware that abrading sound enamel excessively renders that surface more susceptible to the effects of acid erosion. BAG and sodium bicarbonate powders were less invasive when compared to the alumina powder, supporting their use for controlled surface stain removal from enamel where indicated clinically.

Analysis of the mineral composition of hypomineralized first permanent molars.

BACKGROUND/AIM: Hypomineralization of molars and incisors (molarincisor hypomineralization--MIH) is defined as enamel hypomineralization of systemic origin of one or more of the four first permanent molars, which may be associated with changes in the maxillary, and less frequently in the permanent mandibular in cisors. The aim of this study was to investigate the mineral content in hypomineralized teeth as a contribution to understanding the origin of these changes, which will be important for effective restorative approach. METHODS: A total of 10 extracted first permanent molars diagnosed with MIH were used in the study as the experimental group, and intact first premolars extracted for orthodontic reasons were used as the control group. A certain surface of hypomineralized and healthy enamel and dentin was analyzed using a scanning electron microscope equipped with an energy-dispersive spectrometer (SEM/EDS). RESULTS: By conducting quantitative chemical analysis of the distribution of the basic chemical elements, it was found that the concentration of calcium (Ca) and phosphorus (P) was significantly higher in healthy enamel (Ca = 28.80 w%, and P = 15.05 wt%) compared to hypomineralized enamel (Ca = 27.60 wt% and P = 14.32 wt/o). Carbon (C) concentration was statistically significantly higher in hypomineralized enamel (C = 11.70 wt%) compared to healthy enamel (C = 10.94 wt%). Hypomineralized and healthy enamel did not differ significantly regarding the ratio of calcium and phosphorus concentrations whereas the ratio of calcium and carbon concentrations was statistically significantly higher in healthy enamel compared to hypomineralized enamel. CONCLUSION: Concentration of the main chemical elements, primarily calcium and phosphorus, is significantly reduced in hypomineralized enamel whereas carbon concentration is increased compared to healthy enamel.

Calcium hypochlorite as a dentin deproteinization agent: Microleakage, scanning electron microscopy and elemental analysis.

PURPOSE: This study investigated the influence of collagen removal with calcium hypochlorite on the surface morphology of acid-etched dentin and on the microleakage of composite restorations. In addition, the elemental composition (EC) of dentin after removal of the collagen fibrils was analyzed. MATERIALS AND METHODS: Forty third molars received two cavities and were divided into four groups according to dentin treatment: CTRL-no pre-treatment; Na10-10% NaOCl for 30 s; Ca10-10% CaOCl for 30 s, and Ca15-15% CaOCl for 30 s. The cavities were filled using an acetone-based adhesive system and a resin composite; they were then subjected to thermal cycling for 5,000 cycles, immersed in methylene blue for 4 h and sectioned into 1-mm thick slabs. Two examiners evaluated two slices per tooth using a stereomicroscope and assigned the degree of infiltration (scores 0-3). The data were analyzed using the Kruskal-Wallis (α = 0.05). Four teeth received surface treatment according to the groups and were submitted to SEM and EDS to carry at the EC. RESULTS: There was no significant difference between the experimental groups (P = 0.533). CaOCl alters the morphology and surface composition of the dentin, resulting in an increase in the amount of calcium in the interface. CONCLUSIONS: When used prior to an acetone-based adhesive system, CaOCl did not produce any differences in microleakage when compared to the CTRL group or to the Na10 group.

Hierarchical modelling of elastic behaviour of human enamel based on synchrotron diffraction characterisation.

Human enamel is a hierarchical mineralized tissue with a two-level composite structure. Few studies have focused on the structure-mechanical property relationship and its link to the multi-scale architecture of human enamel, whereby the response to mechanical loading is affected not only by the rod distribution at micro-scale, but also strongly influenced by the mineral crystallite shape, and spatial arrangement and orientation. In this study, two complementary synchrotron X-ray diffraction techniques, wide and small angle X-ray scattering (WAXS/SAXS) were used to obtain multi-scale quantitative information about the structure and deformation response of human enamel to in situ uniaxial compressive loading. The apparent modulus was determined linking the external load and the internal strain in hydroxyapatite (HAp) crystallites. An improved multi-scale Eshelby model is proposed taking into account the two-level hierarchical structure of enamel. This framework has been used to analyse the experimental data for the elastic lattice strain evolution within the HAp crystals. The achieved agreement between the model prediction and experiment along the loading direction validates the model and suggests that the new multi-scale approach reasonably captures the structure-property relationship for the human enamel. The ability of the model to predict multi-directional strain components is also evaluated by comparison with the measurements. The results are useful for understanding the intricate relationship between the hierarchical structure and the mechanical properties of enamel, and for making predictions of the effect of structural alterations that may occur due to the disease or treatment on the performance of dental tissues and their artificial replacements.

Ion concentration adjacent to glass-ionomer restorations in primary molars.

OBJECTIVES: The aim was to compare the levels of fluoride, calcium and phosphorus in enamel and dentin alongside glass-ionomer-based restorations over time. METHODS: This CCT consisted of children with cavities in the occlusal surface of primary molars that were restored with either a high-viscosity (Fuji IX GP(®)) or a resin-modified glass-ionomer (Vitremer(®)), being the test groups. Sound teeth (controls) were harvested from the children belonging to the test groups. Sampled teeth were cut in half and the ion concentration measured using EPMA. ANOVAs, and Newman-Keuls tests were performed to analyze the data. The study sample consisted of 35 children having 29 teeth per group available for analyses. RESULTS: Although statistically significantly higher, the mean ion-concentration of calcium in enamel and dentin, and that of phosphorous in dentin hardly differed between the tests and control groups. The mean fluoride concentration in enamel (0.20ppm×10(3) and 0.24ppm×10(3)) and dentin (0.71ppm×10(3) and 0.78ppm×10(3)) surrounding the Fuji IX GP(®) and Vitremer(®) restored teeth, respectively was statistically significantly higher than in enamel (0.12ppm×10(3)) and dentin (0.12ppm×10(3)) for the control teeth. SIGNIFICANCE: The present in vivo investigation showed that fluoride ions are released from high-viscosity and resin-modified glass-ionomer primary restoration into the restorations' surrounding enamel and, and in particular, dentin.

The morphology and mineralization of dental hard tissue in the offspring of passive smoking rats.

OBJECTIVE: To study the effects of maternal passive smoking on the morphology and mineralization of dental hard tissue in offspring rats. DESIGN: We have established a maternal passive smoking model. Offspring rats were sacrificed on the 20th day of gestation (E20) or the 3rd (D3) or 10th day (D10) after birth. We observed hard tissue morphology using Haematoxylin-Eosin (H&E) staining sections, used micro computer tomography (Micro-CT) to measure hard tissue thickness and volume on the mandibular first molars of the offspring rats, and used Micro-CT and energy dispersive X-ray spectroscopy with scanning electron microscopy (SEM/EDS) to determine the hard tissue mineral density and the ratio of calcium atom number/calcium atom+phosphorus atom number (Ca(2+)/P(3-)+Ca(2+)). RESULTS: Overall, the development of dental hard tissue was delayed in the offspring of passive smoking rats. The thickness and volume of hard tissue were lower in the offspring of the maternal passive smoking group than in the offspring of the control group. Mineral density of the hard tissue and the ratio of (Ca(2+)/P(3-)+Ca(2+)) were also reduced in the offspring of the maternal passive smoking group. CONCLUSION: Maternal passive smoking inhibits the morphological development and mineralization level of hard tissue on the mandibular first molars of offspring rats.

Chemical aspects on dental hard tissues in primary teeth from preterm infants.

Preterm children with very low birth weight suffer from several neonatal and postnatal complications that may affect the mineralization of teeth. Clinical and morphological studies have shown enamel aberrations in teeth from preterm children. In this study, the chemical composition in enamel and dentin was compared in primary teeth from preterm children and full-term children, and the relationship between the chemical composition and the morphological appearance was investigated. Enamel and dentin in 17 exfoliated primary teeth, from 14 children with a gestational age below 29 wk, were investigated and compared with 36 exfoliated primary teeth from full-term children, using X-ray microanalyses (XRMA). In comparison with the teeth from the controls, the teeth from preterm children had a higher relative value of carbon (C), a lower relative value of calcium (Ca), a lower ratio of calcium/phosphorus (Ca/P) and a lower ratio of Ca/C throughout the outer part of the enamel. In dentin, the relative values for P were higher, and Ca/P ratio was lower, at the dentin-pulp junction. The Ca/P ratio indicated normal hydroxyapatite in the crystals in enamel and dentin. The lower ratio of Ca/C in the bulk and outer part of the enamel indicated more porous enamel.

Fluoride concentration in dentin of exfoliated primary teeth as a biomarker for cumulative fluoride exposure.

A biomarker for lifetime fluoride exposure would facilitate population-based research and policy making but currently does not exist. This study examined the suitability of primary tooth dentin as a biomarker by comparing dentin fluoride concentration and fluoride exposures. Ninety-nine children's exfoliated primary teeth were collected from 2 fluoridated and 2 fluoride-deficient communities in North Carolina. Coronal dentin was isolated by microdissection and fluoride concentration assayed using the microdiffusion, ion-specific electrode technique. Information on children's fluoride exposures since birth from drinking water, toothpaste, supplements, rinses, food and beverages was collected by a self-reported questionnaire administered to caregivers. Only a small portion of the variance (10%) in incisor dentin fluoride (mean 792, SD 402 mg/kg) was accounted for by the best linear regression model as evaluated by the adjusted R(2). A moderate portion of the variance (60%) of molar dentin fluoride (mean 768, SD 489 mg/kg) was predicted by dietary fluoride supplement exposures, community of residence, and frequent tea consumption. Results for molars suggest that primary tooth dentin concentration may prove to be a satisfactory biomarker for fluoride exposure.

Quantitative analysis of the calcium and phosphorus content of developing and permanent human teeth.

It was the aim of this study to investigate the distribution of Ca, P and C in predentin, dentin and enamel in human tooth buds and permanent teeth by EDX element analysis. The mandible of a 16-week-old human fetus containing eight mineralizing tooth buds and three human permanent molars were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80 microm thickness of the mandible were cut in the frontal-dorsal direction, and polarized light micrographs were taken of these sections. The permanent teeth were cut in mesio-distal direction. The sections were investigated with scanning electron microscopy and EDX element analysis with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, mature dentin, mineralizing enamel and young enamel of developing teeth and mature enamel of permanent teeth. In developing teeth the Ca and P content increased rapidly from outer predentin towards mineralizing dentin. In enamel prisms of developing teeth the Ca and P content increased linearly from the surface towards the enamel-dentin junction. In permanent teeth only a small layer of predentin was found. The Ca and P content in enamel and circumpulpal dentin of permanent teeth was higher than in developing teeth. The Ca/P ratio differed between predentin and dentin areas reflecting different calcium phosphate compositions, but it was the same in mineralizing and young enamel. The differences in the distribution of Ca and P reflect different mineralizing patterns of the enamel and dentin matrices.

Isotopic evidence for age-related immigration to imperial Rome.

Oxygen stable isotope ratios (delta(18)O) have been determined in carbonate in paired first and third molar teeth from individuals (N = 61) who lived in the town of Portus Romae ("Portus") and who were buried in the necropolis of Isola Sacra (First to Third centuries AD) near Rome, Italy. We compare these analyses with data for deciduous teeth of modern Roman children. Approximately one-third of the archaeological sample has first molar (M1) values outside the modern range, implying a large rate of population turnover at that time, consistent with historical data. Delta (18)O(ap) values suggest that a group within the sample migrated to the area before the third molar (M3) crown had completely formed (i.e., between 10 and 17.5 years of age). This is the first quantitative assessment of population mobility in Classical antiquity. This study demonstrates that migration was not limited to predominantly single adult males, as suggested by historical sources, but rather a complex phenomenon involving families. We hypothesize that migrants most likely came from higher elevations to the East and North of Rome. One individual with a higher delta(18)O value may have come (as a child) from an area isotopically similar to North Africa.

Characterization of dentin formed in transplanted rat molars by electron probe microanalysis.

The present study was designed to characterize dentin formed in transplanted rat molars by investigating calcium (Ca), phosphorus (P), and magnesium (Mg) concentrations using electron probe microanalysis (EPMA) as well as examining the rate of dentin matrix formation by vital staining. The unerupted immature lower right second molar in 2-week-old rats was transplanted into the upper right first molar socket. Rats were injected with oxytetracycline, calcein, and alizarin intraperitoneally at 1 day before and 1 and 2 weeks after transplantation, respectively, for vital staining. The maxillae and mandibles were fixed 3 weeks after transplantation, resected, and embedded in resin. Undemineralized sections were cut and examined by fluorescent microscopy and EPMA. The thickness of dentin formed in the first week after transplantation was significantly less than that of dentin formed in any other 1-week period in the transplanted tooth and was about one-fifth the thickness of dentin formed in control teeth. Formation of dentin recovered in the third week after transplantation. In the first week after transplantation, EPMA demonstrated a sharp increase in Mg concentration with a slight decrease in Ca concentration. Thereafter, no significant difference was identified among Ca, P, or Mg concentrations or the Ca/P ratio between transplanted and control teeth. These results suggest that disruption of the circulation and innervation by transplantation cause a temporary change in the matrix formation rate and elemental distribution of dentin, which is subsequently restored within 2 weeks after transplantation.