Neandertal features of the deciduous and permanent teeth from Portel-Ouest Cave (Ariège, France).

OBJECTIVES: We describe 14 unpublished and nine published teeth from the Mousterian level of Portel-Ouest (Ariège, France), dated to 44 ka. In a comparative context, we explore the taxonomical affinities of those teeth with Neandertals and modern humans which are both known to exist at that time. We further make some paleobiological inferences about this human group. METHODS: The comparative analysis of Neandertals and modern humans is based on nonmetric traits at the outer enamel surface and the enamel-dentine junction, crown diameters and three-dimensional (3D) enamel thickness measurements of lower permanent teeth. The crown and roots are explored in detail based on the µCT-scan data to identify the multiple criteria involved in the paleobiological approach. RESULTS: Nonmetric traits and 3D enamel thickness tend to be more similar to Neandertals than modern humans, notably for C1 , P4 , and M2 (included in all analyses) as well as volume of the pulp cavity in roots of the anterior permanent teeth. The Portel-Ouest sample corresponds to a minimum of seven juveniles, one or two adolescents and one adult, which exhibit recurrent linear enamel hypoplasia (up to five events for one individual), the torsiversion of one anterior tooth and irregular oblique wear in some anterior deciduous teeth. DISCUSSION: This morphological study confirms that the remains from Portel-Ouest are Neandertals, associated with a Mousterian complex. Furthermore, we found the expected pattern of mortality and stress for a Neandertal group, that is, various age categories and developmental defects (nonexclusive to Neandertals), while adults are underrepresented and juveniles are overrepresented. Further excavations would contribute finding new remains and maybe complete this demographic profile.

Transition to agriculture in South-Eastern Arabia: Insights from oral conditions.

OBJECTIVES: In Southeast (SE) Arabia, agriculture is supposed to expand around 3000 BC, but its tempo and its actual role in populations' subsistence is still debated by archaeologists. Here, we compare dental health conditions of 11 skeletal samples from coastal and inland sites, dated from the Late Neolithic (ca. 4500-3100 BC) to the Early Bronze Age (EBA), conventionally divided into Hafit (ca. 3100-2700 BC) and Umm an-Nar period (ca. 2700-2000 BC). The goal is to assess long-term trends in subsistence patterns and regional variability during the local transition to agriculture. METHODS: Seven indicators of oral health and childhood stress were analyzed, including dental wear, calculus, caries, alveolar resorption, periapical lesions, ante-mortem tooth loss (AMTL), and linear enamel hypoplasia (LEH). RESULTS: Neolithic coastal populations are globally characterized by high dental wear, high calculus frequency, high LEH frequency, and frequent periodontal disease, whereas they exhibit low abscesses and AMTL frequencies and a total absence of carious lesions. Samples from the Hafit period present high dental wear, low rates of calculus and LEH, frequent periodontal disease, combined with low abscess and AMTL frequencies and absence of caries. By contrast, samples from the Umm an-Nar period exhibit much lower dental wear, calculus and LEH rates, whereas caries, periapical lesions and AMTL frequencies increase significantly. Marked differences were observed between coastal and inland Umm an-Nar groups, the latter presenting significantly higher frequencies of caries, periapical lesions, alveolar resorption and AMTL. DISCUSSION/CONCLUSION: Oral conditions from the Neolithic coastal populations denote a diet mainly composed of unprocessed and abrasive food, with high protein and low carbohydrate intakes, and frequent stress episodes. Although Hafit populations display some changes in oral pathologies, which indicate modifications in their lifestyle and a diversification of the diet, no markers of high carbohydrate intakes were observed in our samples. The impact of agriculture on oral health appears clearly only from the Umm an-Nar period, and is more intense inland than on the coast, where marine resources are still a main component of the diet.

Fluoride/vitamin D tablet supplementation in infants-effects on dental health after 10 years.

OBJECTIVE: We examined whether fluoride/vitamin D supplementation in the first year of life is associated with caries or molar incisor hypomineralization (MIH) at 10 years of age. METHODS: The study population consisted of 406 children for whom information on fluoride/vitamin D supplementation during the first year of life was available. Dental examination at the age of 10 included caries and MIH registration. The results of logistic regression models were adjusted for gender, age, BMI, parental education, and equivalent income. RESULTS: Children receiving supplementation during the entire first year of life had a significantly lower probability of having caries-related restorations in primary teeth in comparison to those who received supplementation for less than 6 months (fluoride supplementation: odds ratio (OR) for d3-4mfs 2.47 (1.32-4.63), for fs 2.70 (1.43-5.10); vitamin D supplementation: OR for d3-4mfs 2.08 (1.00-4.32), fs 2.50 (1.19-5.25)). The majority of logistic regression analyses indicated no association between supplementation and MIH. CONCLUSIONS: It was found a consistent significant caries-preventive effect in the primary dentition of children who received fluoride (256/372)/vitamin D supplementation (274/376) in all 12 months over the first year of life; no effects were observed for permanent dentition. The high parental interest in supplementation is linked to an imbalance of the study groups. Furthermore, tooth brushing frequency, use of fluoride toothpastes and/or other oral hygiene products were not recorded during the observation period which may also confound the results. CLINICAL RELEVANCE: Fluoride/vitamin D supplementation can be used in children for preventing caries in the primary dentition.

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.

Plasticity and constraint in response to early-life stressors among late/final Jomon period foragers from Japan: evidence for life history trade-offs from incremental microstructures of enamel.

This study evaluates two hypotheses that address how Late/Final Jomon period people responded to early-life stress using linear enamel hypoplasia (LEH) and incremental microstructures of enamel. The first hypothesis predicts that Jomon people who experienced early-life stressors had greater physiological competence in responding to future stress events (predictive adaptive response). The second hypothesis predicts that Jomon people traded-off in future growth and maintenance when early investment in growth and survival was required (plasticity/constraint). High resolution tooth impressions were collected from intact, anterior teeth and studied under an engineer's measuring microscope. LEH were identified based on accentuated perikymata and depressions in the enamel surface profile. Age of formation for each LEH was estimated by summing counts of perikymata and constants associated with crown initiation and cuspal enamel formation times. The relationship between age-at-first-defect formation, number of LEH, periodicity between LEH, and mortality was evaluated using multiple regression and hazards analysis. A significant, positive relationship was found between age-at-death relative to age-at-first-defect formation and a significant, negative relationship was found between number of LEH relative to age-at-first-defect formation. Individuals with earlier forming defects were at a significantly greater risk of forming defects at later stages of development and dying at younger ages. These results suggest that Late/Final Jomon period foragers responded to early-life stressors in a manner consistent with the plasticity/constraint hypothesis of human life history. Late/Final Jomon period individuals were able to survive early-life stressors, but this investment weakened responses to future stress events and exacerbated mortality schedules.

A comparative study of stress episode prevalence and duration among Jomon period foragers from Hokkaido.

This study reconstructs linear enamel hypoplasia (LEH) prevalence and stress episode duration among Jomon period foragers from Hokkaido, Japan (HKJ). Results are compared to Jomon period samples from coastal Honshu, Japan (HSJ) and Tigara Inupiat from Point Hope, Alaska (PHT) to provide a more comprehensive perspective on the manifestation of stress among circum-Pacific foragers. LEH were identified macro- and microscopically by enamel surface depressions and increased perikymata spacing within defects. Individuals with more than one anterior tooth affected by LEH were labeled as LEH positive. Stress episode durations were estimated by counting the number of perikymata within the occlusal wall of each LEH and multiplying that number by constants reflecting modal periodicities for modern human teeth. LEH prevalence and stress episode duration did not differ significantly between the two Jomon samples. Significantly greater frequencies of LEH were found in HKJ as compared to PHT foragers. However, HKJ foragers had significantly shorter stress episode durations as compared to PHT. This suggests that a greater proportion of HKJ individuals experienced stress episodes than did PHT individuals, but these stress events ended sooner. Similarity in stress experiences between the two Jomon samples and differences between the HKJ and PHT are found. These findings are important for two reasons. First, stress experiences of foraging populations differ markedly and cannot be generalized by subsistence strategy alone. Second, due to significant differences in episode duration, stress experiences cannot be understood using prevalence comparisons alone.

Temporal variation and interaction between nutritional and developmental instability in prehistoric Japanese populations.

We examined nutritional and developmental instability in prehistoric Japan, using data from 49 individuals across 13 archaeological sites. Hypoplasia incidence was used as a measure of nutritional stress, and fluctuating asymmetry (of upper facial breath, orbital breadth, and orbital height) as an indirect assessment of developmental instability. Abundant resources due to a stable climate during the Middle Jomon (5,000-3,000 BP) encouraged population growth, which led to regional cultural homogeneity and complexity. A population crash on Honshu in the Late/Final Jomon (roughly 4,000-2,000 BP) led to regionally divergent subsistence economies and settlement patterns. We find that the nutritional stress was consistent between periods, but developmental instability (DI) decreased in the Late/Final Jomon. While the DI values were not statistically significant, the higher values for Middle Jomon may result from sedentism, social stratification, and differential access to resources. On Hokkaido, Jomon culture persisted until the Okhotsk period (1,000-600 BP), marked by the arrival of immigrants from Sakhalin. Nutritional stress was consistent between Middle and Late/Final Jomon, but DI increased in the Late/Final. Nutritional and developmental instability decreased from Late/Final to Okhotsk, suggesting a positive immigrant effect. We expected to find an association between stress markers due to the synergistic relationship between nutrition and pathology. The data support this hypothesis, but only one finding was statistically significant. While high critical values from small sample sizes place limits on the significance of our results, we find that the impact of environmental and cultural change to prehistoric Japanese populations was minimal.

Hypoplastic enamel defects and environmental stress in a homogeneous Romano-British population.

This study investigated hypoplastic enamel defects in a well-defined sample of Romano-Britons from the 3rd to the 5th century AD and compared the findings with a modern British sample investigated by the same authors. All 178 excavated skulls with intact dentitions were examined for hypoplastic defects using the Federation Dentaire International (FDI) Developmental Defects of Enamel Index criteria. Histopathological and microradiographic sections were prepared of 5 teeth. Hypoplastic defects were found in the teeth of 37% of skulls, with 25% having 4 or more teeth affected. The teeth most frequently involved were canines. Of the defects, 75% were horizontal grooves, 12.7% were pitting, and 7.1% were areas of missing enamel. The location of defects was 82% buccal, 16.5% lingual, and 1.2% occlusal. The reproducibility of diagnosis was 84%. Microscopic and microradiographic investigations showed areas of hypomineralization of enamel and wide zones of interglobular dentine related to the hypoplastic grooves. There was higher frequency, different morphology, and greater severity of hypoplastic enamel defects compared with the modern British sample. The defects may be related to repeated environmental stresses between the ages of 2 and 6 yr. Identified environmental stresses in these Romano-Britons, including high lead ingestion, poor nutrition, and recurrent infections, may be important etiological factors for the enamel defects.

Exploring the relationship between hypoplasia and odontometric asymmetry in Isola Sacra, an imperial Roman necropolis.

Anthropological studies reporting odontometric asymmetry values or dental enamel hypoplasia frequencies use these markers as a record of physiological perturbations occurring during dental development. While both markers indirectly suggest the amount of relative stress a population might have experienced, a relationship between the two has been explored only recently in the literature. In this study, we address the possibility of such a relationship in two ways. First, Kendall's tau B correlations test the degree of relationship on the level of the individual between hypoplasia presence/absence (P/A) and severity of hypoplasia appearance (PS) data for the anterior dentition and directional (DA) and fluctuating asymmetry (FA) data for concurrently developing molars pairs. Second, an F-test explores between-group (ranked hypoplastic individuals and non-hypoplastic individuals) variance about the mean, expecting the hypoplastic individuals to be more variable. The sample consists of 72 individuals from the Isola Sacra necropolis, which is associated with Portus, the port city of ancient Rome. Results indicated only a very weak predictive relationship between some variables and few significant differences in variation. However, variance follows trends in published literature. Possible explanations for the lack of interaction on the level of the individual include both etiological and genetic susceptibility factors that are significant in and of themselves as they suggest a more complex reading of the hard tissue evidence for stress in archaeological populations.

Enamel hypoplasias and physiological stress in the Sima de los Huesos Middle Pleistocene hominins.

This study presents an analysis of linear enamel hypoplasias (LEH) and plane-form defects (PFD) in the hominine dental sample from the Sima de los Huesos (SH) Middle Pleistocene site in Atapuerca (Spain). The SH sample comprises 475 teeth, 467 permanent and 8 deciduous, belonging to a minimum of 28 individuals. The method for recording PFD and LEH is discussed, as well as the definition of LEH. The prevalence of LEH and PFD in SH permanent dentition (unilateral total count) is 4.6% (13/280). Only one deciduous tooth (lower dc) showed an enamel disruption. Prevalence by individual ranges from 18.7-30%. The most likely explanation for the relatively low LEH and PFD prevalence in the SH sample suggests that the SH population exhibited a low level of developmental stress. The age at occurrence of LEH and PFD was determined by counting the number of perikymata between each lesion and the cervix of the tooth. Assuming a periodicity of nine days for the incremental lines, the majority of LEH in the SH sample occurred during the third year of life and may be related to the metabolic stress associated with weaning.

Prevalence and the duration of linear enamel hypoplasia: a comparative study of Neandertals and Inuit foragers.

As a dental indicator of generalized physiological stress, enamel hypoplasia has been the subject of several Neandertal studies. While previous studies generally have found high frequencies of enamel hypoplasia in Neandertals, the significance of this finding varies with frequencies of enamel hypoplasia in comparative samples. The present investigation was undertaken to ascertain if the enamel hypoplasia evidence in Neandertals suggests a high level of physiological stress relative to a modern human foraging group, represented here by an archaeological sample of Inuit from Point Hope, Alaska. Unlike previous studies, this study focused specifically on linear enamel hypoplasia (LEH), emphasizing systemic over localized causes of this defect by considering LEH to be present in an individual only if LEH defects occur on two anterior teeth with overlapping crown formation periods. Moreover, this study is the first to evaluate the average growth disruption duration represented by these defects in Neandertals and a comparative foraging group. In the prevalence analysis, 7/18 Neandertal individuals (from Krapina and southern France) and 21/56 Neandertal anterior teeth were affected by LEH, or 38.9% and 37.5% respectively. These values do not differ significantly from those of the Inuit sample in which 8/21, or 38.1% of individuals, and 32/111, or 28.8% of anterior teeth were affected. For the growth disruption duration analysis, 22 defects representing separate episodes of growth disruption in Neandertals were compared with 22 defects in the Inuit group using three indicators of duration: the number of perikymata (growth increments) in the occlusal walls of LEH defects, the total number of perikymata within them, and defect width. Only one indicator, the total number of perikymata within defects, differed significantly between the Inuit and Neandertal groups (an average of 13.4 vs. 7.3 perikymata), suggesting that if there is any difference between them, the Inuit defects may actually represent longer growth disruptions than the Neandertal defects. Thus, while stress indicators other than linear enamel hypoplasia may eventually show that Neandertal populations were more stressed than those of modern foragers, the evidence from linear enamel hypoplasia does not lend support to this idea.

Later Middle Pleistocene human remains from the Almonda Karstic system, Torres Novas, Portugal.

Later Middle Pleistocene archeological deposits of the Galeria Pesada (Gruta da Aroeira), Almonda Karstic System, Torres Novas, Portugal, yielded two archaic human teeth, a mandibular canine and a maxillary third molar. The C(1)presents moderate and asymmetrical shoveling with a stout root. The slightly worn M(3)exhibits at least four cusps with a large hypocone, three roots with large radicular plates, and an absence of taurodontism. They are moderately large for later Middle Pleistocene humans in their buccolingual crown diameters, although the M(3)mesiodistal diameter is modest. The C(1)exhibits labial calculus and multiple linear hypoplastic defects, but the M(3)is lesion free. Both teeth are morphologically similar to those of other Middle Pleistocene European humans and reinforce a pattern of dental hypertrophy among these archaic Homo.

Enamel hypoplasia in a litter of rats with alloxan-induced diabetes mellitus.

Enamel hypoplasia is an important clinical problem commonly seen in children born to diabetic women. We aimed to characterize the enamel hypoplasia in Wistar rats born to alloxan-induced diabetes mellitus rats. Groups consisted of pregnant rats supplemented (ISDR) or not (NISDR) with insulin and controls, in which sterile saline solution was administered instead of alloxan or insulin. The mandibular incisors of one-month-old rats born to these mothers were analyzed. Whitish defective enamel was found macroscopically in both experimental groups (ISDR = 37.5%, NISDR = 33.3%) but not in the control group. Mild to severe enamel hypoplasia was observed by scanning electron microscopy (ISDR = 93.8%; NISDR = 100%, control = 4.2%). The severity of hypoplasia correlated positively with the maternal level of blood glucose. In conclusion, the intensity of enamel hypoplasia in the teeth of the litter born to alloxan-induced diabetic rats was variable and was dependent on the glycemic level of the pregnant rat.

Enamel hypoplasia in a litter of rats with alloxan-induced diabetes mellitus

Enamel hypoplasia is an important clinical problem commonly seen in children born to diabetic women. We aimed to characterize the enamel hypoplasia in Wistar rats born to alloxan-induced diabetes mellitus rats. Groups consisted of pregnant rats supplemented (ISDR) or not (NISDR) with insulin and controls, in which sterile saline solution was administered instead of alloxan or insulin. The mandibular incisors of one-month-old rats born to these mothers were analyzed. Whitish defective enamel was found macroscopically in both experimental groups (ISDR = 37.5 percent, NISDR = 33.3 percent) but not in the control group. Mild to severe enamel hypoplasia was observed by scanning electron microscopy (ISDR = 93.8 percent; NISDR = 100 percent, control = 4.2 percent). The severity of hypoplasia correlated positively with the maternal level of blood glucose. In conclusion, the intensity of enamel hypoplasia in the teeth of the litter born to alloxan-induced diabetic rats was variable and was dependent on the glycemic level of the pregnant rat

Brief communication: diachronic investigation of linear enamel hypoplasia in prehistoric skeletal samples from Trentino, Italy.

Linear enamel hypoplasia was scored on Neolithic, Copper Age, and Early Bronze Age samples from the Trentino region, Italy, in order to compare the extent of growth disruption in different biocultural subsistence systems (foragers with little agriculture, to agriculturists and agropastoralists). The Early Bronze Age sample shows a higher frequency of enamel defects and an earlier chronological onset than the early Neolithic sample. The higher frequency of defects in the Bronze Age sample could be linked to less diversified nutrition and, because of increased sedentism, a higher risk of disease.

Histological and analytical studies of a tooth in a patient with cleidocranial dysostosis.

A histopathological and analytical study of a permanent tooth from a patient with cleidocranial dysostosis (CCD) was performed. The patient was a 47-year-old woman, who had 10 erupted permanent teeth and 2 partially erupted and 19 completely impacted teeth, including supernumerary teeth. The erupted right upper premolar was extracted and observed using a light microscope and an electron probe X-ray microanalyzer (EPMA). Findings showed enamel hypoplasia, predominantly irregular globular dentin and Tomes' granular layer, and a complete lack of cellular cementum in the ground section. The incremental von Ebner and counter Owen lines were obscure. Comparative quantitative analysis using the EPMA showed that the quantities of calcium and phosphate were lower in the enamel and dentin than those of the control sample.

Oral manifestations seen in association with a case of trisomy for the short arm of chromosome 9.

A case of trisomy for the short arm of chromosome 9 in a 13-year-old boy is described. Particular emphasis is placed upon a number of abnormal dental findings, which include enamel hypoplasia, hypodontia, and severe dental crowding. The difficulties of providing comprehensive dental treatment in cases such as these is discussed.

Hypoplastic area method for analyzing dental enamel hypoplasia.

Most analyses of dental enamel hypoplasia compare frequencies of disturbed tooth types, which do not account for variability in the area of affected enamel. An alternate methodology, hypoplastic area, is presented here that accounts for this variability by combining acute and continuous enamel hypoplasia into an interval-level variable. The method compares samples based on individuals, by multiple tooth type variables, or by a single value rather than by tooth types. Use of the hypoplastic area method is illustrated by analyzing human skeletal dentitions in three archaeological samples: Meroitic Nubians from Semna South, Sudan; Anasazi from Navajo Reservoir, New Mexico; and Mogollon from Grasshopper Pueblo, Arizona. Both univariate and multivariate statistical tests are employed to assess variation in defects between individuals and samples. By incorporating measurements of continuous defects, the hypoplastic area method provides information beyond that of frequency data in comparing levels of stress. Flexibility of the method is also discussed.

Oral manifestations of familial hypophosphatemic rickets after phosphate supplement therapy: a review of the literature and report of case.

The patient was a seven-year-old boy with familial vitamin D-resistant hypophosphatemic rickets. His mother, and her mother, were also affected. Before phosphate treatment was introduced in the patient, an impaired incorporation of calcium, and its exchange with sodium, was thought to be the principal etiological factor in the formation of globules. Supplementation therapy then resulted in a less elevated Ca/P ratio in the root area of the affected teeth, as well as a cure for the boy's bone structure. What the therapy did not cure was the globular appearance of the dentin and the hypomineralized stripe of pulpal horn extending to the cusp tips, an apparent permanent outcome of the disease.

Mechanical surface analysis of bone: a case study of cut marks and enamel hypoplasia on a Neolithic cranium from Sweden.

A method for measuring, recording, and studying fine surface irregularities in three dimensions is presented. The method, which involves recording the movements of a diamond-tipped stylus as it scans the surface being studied, is demonstrated on a Neolithic cranium from Sweden. The cranium emanates from a pile dwelling dated to about 3000 B.C. Its frontal bone exhibits distinct cut marks indicative of scalping, and the teeth show signs of enamel hypoplasia. The surface topography of the putative cut marks and hypoplastic enamel were investigated using the stylus method. Measurements of enamel hypoplasia were also carried out for comparison on a front tooth from the lower jaw, and the cut mark study was compared with scanning electron micrographs. The results of this case study demonstrate that the stylus method can obtain high-resolution measurements of fine surface details directly on the original bone without preparation of or damage to the specimen.