Taurodontism and the presence of an extra Y chromosome: study of 47,XYY males and analytical review

A sample of 47,XYY males was examined for taurodontism to provide further information on the effects of chromosome aneuploidies on the trait. The etiology of taurodontism is reviewed in light of recent findings. Two models have been put forward to explain the association of taurodontism with chromosome abnormalities: (1) Taurodontism results from a generalized disruption of developmental homeostasis, and (2) the development of taurodontism reflects a more specific action of the genes. The recent findings in 45,X females indicate that this chromosome aneuploidy does not have any effect on the development of taurodontism, in contrast to the findings of increased frequency of the trait in individuals with extra X chromosomes. The present results in 47,XYY males suggest that the presence of an extra Y chromosome does not cause an increase in the expression of taurodontism. It is concluded that the observed variation in the occurrence of taurodontism in individuals with sex chromosomes aneuploidies does not corroborate the hypothesis of disrupted homeostasis. Instead, the findings indicate that more specific action of gene(s) on the X chromosome is involved. We suggest that the effect of the Y chromosome on growth of both enamel and dentin, possibly in a regulative way, could be involved in the balanced growth of dental structures in 47,XYY males.     

Investigating prevalence of dental anomalies in Eastern Province of Saudi Arabia through digital orthopantomogram

ObjectiveThe aim of this study was to investigate the prevalence of dental anomalies in the Eastern Province of Saudi Arabia using the digital Orthopantomography (OPG).MethodsA retrospective radiographic study was performed in which digital OPGs of 1189 subjects, ages ranging between 7 and 65 years were reviewed, and 1104 fulfilled inclusion criteria. Statistical analysis was performed. The OPGs were reviewed for congenitally missing teeth, impactions, ectopic eruption, supernumerary teeth, odontomas, dilacerations, taurodontism, dens in dente, gemination and fusion.ResultsOPGs of 1104 patients with mean age 35.32 ± 16.63 were included. The total prevalence of developmental anomalies in this study was 36.3% (401/1104). Male and female subjects with anomalies were 133 (33.2%) and 268 (66.8%) respectively. The prevalence of dilacerated teeth 300 (30.2%), congenitally missing teeth was 246 (24.7%), supernumerary teeth 18 (1.8%), talon cusp and taurodontism were seen in one patient each 1 (0.1%). Of these, a total of 15 (1.5%) anomalies were noted in pediatric patients.ConclusionsDilaceration was the most prevalent anomaly (30.2%) in the studied sample followed by congenitally missing teeth (23.4%). Talon cusp, concrescence/fusion, and taurodontism were the least prevalent anomalies.     

X chromosome effects and their interactions with mitochondrial effects

We report a simple and rapid method for detecting additive genetic variance due to X-linked loci in the absence of marker data for this chromosome. We examined the interaction of this method with an established method for detecting mitochondrial linkage (another source of sex-asymmetric genetic covariance). When applied to data from the Collaborative Study on the Genetics of Alcoholism, this method found evidence of X-chromosomal linkage for one continuous trait (ntth1) and one discrete trait (SPENT). Evidence of mitochondrial contribution was found for one discrete trait (CRAVING) and three continuous traits (ln(CIGPKYR), ecb21, and tth1). Results for ntth1 suggest that methods that do not also allow for male-female heterogeneity in environmental variance may be overly conservative in detection of X-chromosomal effects.     

Flow cytometric DNA analyses of epithelial dysplasia of the esophagus

OBJECTIVE: To investigate, with flow cytometry, DNA aneuploidy as a marker of early carcinogenesis in dysplastic esophageal lesions. STUDY DESIGN: DNA content of exfoliated cells from 789 cases of esophageal dysplasia (including mild dysplasia, 195 cases; moderate dysplasia, 383 cases; and severe dysplasia, 211 cases) was determined with a FACS 420 flow cytometer. RESULTS: Cellular DNA content was closely related to the severity of dysplasia. The carcinogenesis rate in patients with dysplasia showed that DNA aneuploidy was significantly higher than in patients showing DNA diploidy. CONCLUSION: DNA aneuploidy in dysplastic lesions is a very important early signal of carcinogenesis. Patients with dysplastic lesions showing DNA aneuploidy should be treated and closely followed.     

Taurodontism: A biometric study

This study has been carried out in order to clarify various aspects of the phenomenon known as taurodontism. Samples of both taurodont and non-taurodont teeth were measured and statistical analyses were performed on the resultant data from which various conclusions may be drawn. The most important conclusion is that this phenomenon may be defined metrically. The distributions have shown that the taurodont trait grades into the normal and it is quite difficult to make a subjective judgment at the low end of the taurodont range. It is for this reason that an accurate mathematical means for performing this task is so invaluable. The question of the nature of cuneiform single rooted molars was also investigated, and they were found not to be true taurodonts although the statistical procedure classed them as such. It was demonstrated that through the construction of simple plots these teeth could be eliminated from any group classed by analysis as taurodonts. Various metrical attributes were evaluated with respect to their ability to distinguish taurodonts, and two were found to be satisfactory for this purpose in most cases. Certain changes in molar morphology regarding caries and age were also investigated.     

Occurrence of herpes simplex virus 1 and three periodontal bacteria in patients with chronic periodontitis and necrotic pulp

Viral and bacterial associations appear to be implicated in the development of periodontal infections. Little information is available describing the periodontopathic agents in root canals with necrotic pulp. In this study, the occurrence and the combinations among herpes simplex virus type 1 (HSV-1) and Dialister pneumosintes, Tannerella forsythia, and Treponema denticola in patients with chronic periodontitis and necrotic pulp were evaluated. Clinical samples from healthy subjects and patients with periodontal or pulp infections were analyzed using a nested polymerase chain reaction PCR to detect HSV and PCR to detect the 3 periodontal bacteria. The presence of Tannerella forsythia and Treponema denticola was observed in healthy, periodontitis, and necrotic pulp patients. HSV was observed in periodontitis and necrotic pulp patients, and no healthy subject harbored D. pneumosintes or HSV. The occurrence of Tannerella forsythia was not statistically significant in patients with necrotic pulp (P = 0.704). Periodontal bacteria were observed varying from 10.3% to 20.7% in periodontitis and necrotic pulp patients. The presence of Treponema denticola - HSV association was predominant in patients showing necrotic pulp (24.1%); however, HSV alone was observed in one patient with periodontitis and in another patient with necrotic pulp. The presence of double association among bacteria or bacteria - HSV could indicate a role in both periodontitis and necrotic pulp, and Tannerella forsythia - Treponema denticola - HSV and Tannerella forsythia - D. pneumosintes - Treponema denticola - HSV associations might be important in periodontitis.     

Radiographic study of the Broadbeach Aboriginal dentition

This study forms part of a larger anthropological investigation of the Ngaraangbal Aboriginal Tribe's ancestral burial ground at Broadbeach, Australia. It examines the dentition, records the associated pathology in a noninvasive manner, and relates this to the likely subsistence diet of the tribe. The Broadbeach osteological collection was returned for reburial in 1985; however, radiographic and photographic records of 36 adult males were available. These form the basis of our study. The pathology noted in the study sample was compared with a representative sample (n = 38) of pre-European Aboriginal remains from throughout Queensland for verification purposes only. Rates of dental pathology and injury were calculated from the radiographic and photographic records. There was a significant rate of tooth-wear related intra-bony pathology (4.0%), moderate to severe alveolar bone loss, and heavy dental attrition, of which the mandibular posterior teeth were the most severely affected. Caries prevalence (0.8%) was low for hunter-gatherer populations. A large number of molar pulp chambers had a distinctive “cruciate” morphology resulting from the formation of secondary dentine and pulp stones. Injuries and abnormalities included upper central incisor avulsion (58.3%) and taurodontism. These results support the proposal that the Ngaraangbal tribe was a hunter-gatherer population subsisting on an abrasive diet that included marine foods. Am J Phys Anthropol 107:211–219, 1998. © 1998 Wiley-Liss, Inc.     

Structure and Development of Teeth in Three Armoured Catfish, Corydoras aeneus, C. arcuatus and Hoplosternum littorale (Siluriformes, Callichthyidae)

We have studied the premaxillary teeth in three armoured catfish, Corydoras aeneus, C. arcuatus and Hoplosternum littorale , by means of light and electron microscopy, in order to compare their development, fine structure and mode of attachment with that of odontodes and other teleost teeth. A premaxillary dentition consisting of small (50–100 μm long) slender pointed teeth showing no true replacement is only present in larval and juvenile stages and is subsequently lost, possibly in relation to a change in feeding mode from predatory to bottom feeder. Like odontodes, teeth are composed of dentine surrounding a pulp cavity and are covered by a hypermineralized cap. Particular features, also found in odontodes, are the absence of dentinal tubules and of nerves and capillaries in the pulp cavity, both possibly related to the small size of the teeth. The irregular pattern of implantation and the variability in attachment mode (primary and/or secondary attachment bone, fusion, mere apposition or ligamentous connection) distinguish the teeth from most other teleost teeth and from odontodes and are interpreted as reflecting considerable differences in dynamics of remodeling of the supporting element (premaxillary bone vs scute). This comparison of teeth and odontodes strongly supports current views according to which teeth and odontodes are two very closely related phenotypic expressions of a single, modifiable, morphogenetic system probably rooted in the earliest stages of vertebrate evolution.     

Taurodont, pyramidal and fused molar roots associated with other anomalies in a kindred

Crown characteristics have been the parameter most frequently utilized in studies of tooth morphology. Dental root structures have received relatively little attention. Examination of unusual molar roots in a kindred has enabled us to (1) establish a typology for classifying molar roots, (2) devise a methodology for evaluating the degree of taurodontism and (3) hypothesize about phylogenetic, ontogenetic and genetic aspects of root morphology. The roots of molar teeth were studied radiographically in 20 members of a family of English–German ancestry in which there was no consanguinity. Taurodont, pyramidal (single conical root) and fused molar roots were common. Other ectodermal and mesodermal anomalies (unusual upper lip, glaucoma, syndactyly and clinodactyly) were also present. This unique constellation of dental, cutaneous, ocular and bone abnormalities constitutes a previously undescribed syndrome. Unusual roots may be a genetic marker, and the finding of unusual roots, such as prismatic or wholly pyramidal, should prompt a search for other abnormalites. Dental trait analysis for genetic and microevolutionary studies should include root, as well as crown, characteristics.     

Dental findings in osteogenesis imperfecta: II. Dysplastic and other developmental defects

Orthopantomograms of 49 patients with osteogenesis imperfecta (OI) classified according to Sillence were examined for dysplastic dentin defects and other developmental abnormalities of the teeth. Thistle-tube-shaped pulps in the permanent teeth were observed in five patients. Four of them had pulp stones in several teeth. Apically extended pulp chambers were present in 3/49 patients, and the structure of the mandible was cystic in 1/49. These defects occurred in patients with type I or unclassifiable OI and were mainly not associated with type I dentinogenesis imperfecta (DI). The prevalence rates of invaginations (10.2%) and hypodontia of permanent teeth (18.4%) exceeded those in the normal population. The frequent developmental disturbances of the teeth in OI may be secondary to the connective tissue defect. The relation of the dysplastic defects other than type I DI to OI remains to be clarified.     

Logistic analysis of the effects of shovel trait on Carabelli's trait in a mongoloid population

Mongoloid populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the effects of the shovel trait on Carabelli's trait in a Mongoloid population. The research design sought a population that resides in an isolated area and exhibits low admixture with neighboring populations. The Mongoloid group selected for study was the Bunun tribe of aborigines who inhabit an alpine area in Taiwan. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After adjusting for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of three, an effect that is significant. © 1996 Wiley-Liss, Inc.     

Geschlechtsgebunden-dominant erbliche Zahnunterzahl

Zusammenfassung Zahnunterzahl, die durch vier Generationen einer Sippe regelmäßig vererbt wird, tritt ohne Ausnahme im männlichen Geschlecht als Oligodontie, im weiblichen Geschlecht als Hypodontie in Erscheinung. Übertragung des Merkmals vom Vater auf den Sohn wird nicht beobachtet. Obwohl keine enge Koppelung mit Xg gefunden wird, ist ein X-chromosomales Gen wahrscheinlich.

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Reduktion of the number of teeth is inherited as a single dominant trait through four generations of a large kindred. The anomaly is present as oligodontia in males and as hypodontia in females only. It seems to be conditioned by an X-chromosomal gene although no strong linkage with Xg could be shown. Transmission from father to son was not observed.

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Herrn Prof. Dr. Dr. E. Wannenmacher zum 70. Geburtstag, (22. 11. 1967).     

Viability of pulp stromal cells in cryopreserved deciduous teeth

The cryopreservation of exfoliated deciduous teeth and harvesting of stem cells from them as required would reduce the costs and efforts associated with banking stem cells from primary teeth. The aim of this study was determine whether the viability of pulp stromal cells from deciduous teeth was influenced by the cryopreservation process itself or the period of cryopreservation. In total, 126 deciduous teeth were divided into three groups: (1) fresh, (2) cryopreserved for <3 months (cryo<3), and (3) cryopreserved for 3–9 months (cryo3–9). The viability of the pulp tissues was compared among the three groups by evaluating the outgrowth from pulp tissues and cell activity within those pulp tissues. In addition, the terminal deoxynucleotidyl transferase-mediated dUTP–biotin nick end labeling (TUNEL) assay was performed to compare cell apoptosis within fresh pulp tissue and pulp tissue that had been cryopreserved for 4 months. The outgrowth from and cell activity within the pulp tissues did not differ significantly between the fresh and cryo<3 pulp tissues. However, these parameters were significantly reduced in the cryo3–9 pulp tissue. In TUNEL assay, 4-month cryopreserved pulp tissues has more apoptotic cells than fresh group. In conclusion, it is possible to acquire pulp stromal cells from cryopreserved deciduous teeth. However, as the period of cryopreservation becomes longer, it is difficult to get pulp cells due to reduced cell viability.     

Mutant DLX 3 disrupts odontoblast polarization and dentin formation

Tricho-dento-osseous (TDO) syndrome is an autosomal dominant disorder characterized by abnormalities in the thickness and density of bones and teeth. A 4-bp deletion mutation in the Distal-Less 3 (DLX3) gene is etiologic for most cases of TDO. To investigate the in vivo role of mutant DLX3 (MT-DLX3) on dentin development, we generated transgenic (TG) mice expressing MT-DLX3 driven by a mouse 2.3 Col1A1 promoter. Dentin defects were radiographically evident in all teeth and the size of the nonmineralized pulp was enlarged in TG mice, consistent with clinical characteristics in patients with TDO. High-resolution radiography, microcomputed tomography, and SEM revealed a reduced zone of mineralized dentin with anomalies in the number and organization of dentinal tubules in MT-DLX3 TG mice. Histological and immunohistochemical studies demonstrated that the decreased dentin was accompanied by altered odontoblast cytology that included disruption of odontoblast polarization and reduced numbers of odontoblasts. TUNEL assays indicated enhanced odontoblast apoptosis. Expression levels of the apoptotic marker caspase-3 were increased in odontoblasts in TG mice as well as in odontoblastic-like MDPC-23 cells transfected with MT-DLX3 cDNA. Expression of Runx2, Wnt 10A, and TBC1D19 colocalized with DLX3 expression in odontoblasts, and MT-DLX3 significantly reduced expression of all three genes. TBC1D19 functions in cell polarity and decreased TBC1D19 expression may contribute to the observed disruption of odontoblast polarity and apoptosis. These data indicate that MT-DLX3 acts to disrupt odontoblast cytodifferentiation leading to odontoblast apoptosis, and aberrations of dentin tubule formation and dentin matrix production, resulting in decreased dentin and taurodontism.In summary, this TG model demonstrates that MT-DLX3 has differential effects on matrix production and mineralization in dentin and bone and provides a novel tool for the investigation of odontoblast biology.     

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.     

Kroemmelbeinia n. g., eine neue Ostracoden-Gattung aus dem marinen oberpliozän der Insel Kos (Griechenland)

Among the cytherine ostracodes possessing caudal process a new genusKroemmelbeinia is defined by its hinge-element. In its habitus, and its structure particularly the punctate surface and the inner lamella the new genusKroemmelbeinia resembles the genusMicrocytherura G. W. Müller, but which possesses smaller valves. The characteristic hinge-elementsof Kroemmelbeinia are: both terminal teeth in the left valve crenulate, interior with 5–6 terminal teeth in the left valve crenulate, interior with 5–6 toothlets, and posterior with 6–7 connected by a narrow and finely crenulate groove. By this hinge-constructionKroemmelbeinia differs fromMicrocytherura (Tetracytherura) Ruggieri 1952 and also from other genera(Cytheropteron, Perissocytheridea) of similar outline.     

The genetic polymorphism of the thyroxine-binding globulin (TBG)

Summary Hereditary deficiency of the thyroxine-binding globulin (TBG) has been described in 17 families, in 12 of which it is X-chromosomal inherited. Different modes of transmission can be assumed for some of the other families but are not yet warranted. Genetic elevation of TBG has been described in 7 families. This trait is presumably uniformly X-chromosomal inherited.

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Zusammenfassung Ein erblicher Mangel von thyroxinbindendem Globulin (TBG) ist bisher bei 17 Familien beschrieben worden, von denen bei 12 Familien eine X-chromosomale Vererbung angenommen werden kann. Bei einigen der übrigen Familien muß eine andersartige Vererbung angenommen werden, doch konnte kein anderer Erbgang bisher gesichert werden. Eine genetische Vermehrung des thyroxinbindenden Globulin wurde bei 7 Familien beschrieben. Dieses Merkmal wird vermutlich in allen Fällen X-chromosomal vererbt.

     

The Papillon-Lefèvre syndrome: Keratosis palmoplantaris with periodontopathy

Summary The Papillon-Lefèvre syndrome (PLS) is an autosomal recessive trait characterized by diffuse transgredient palmar-plantar keratosis (PPK) and premature loss of both the deciduous and permanent teeth. In most cases, the PPK is noted within the first 3 years of life. The periodontal lesions begin shortly after the start of both the primary and the permanent dentitions. The teeth are affected in the order of their eruption, exhibiting inflammation of the periodontal tissue, bleeding of the gums, pocket formation, lossening, and finally spontaneous exfoliation without showing definite signs of root resorption. After an edentulous interval, the same process begins anew shortly after the second dentition.Ectopic intracranial calcifications, mental retardation, and increased susceptibility to infections have often been seen in PLS patients and may thus be regarded as facultative signs.     

金属烤瓷全冠修复老年人活髓隐裂牙适应证及临床疗效

目的：探讨老年人活髓隐裂牙应用金属烤瓷全冠修复临床效果及适应症。方法：选取本院2006年1月至2011年1月期间收治的356例老年活髓隐裂牙合计621颗为研究对象,根据患牙疼痛程度随机将患者分为咬合疼痛组（A组）104例合计215颗患牙,咬合伴过敏性冷热刺激痛组（B组）122例合计232颗患牙,咬合伴延续性冷热刺激疼痛组（C组）130例合计174颗患牙,所有患者均接受金属烤瓷全冠修复,观察患者在治疗后1个月、6个月、12个月、18个月、24个月治愈情况以及牙髓及根尖周病变及牙髓发生情况。结果：与C组相比,A组、B组术后1个月、6个月、12个月、18个月、24个月治愈率以及总有效率较高,差异有统计学意义（P〈0．05）。结论：金属烤瓷全冠修复适合于轻微咬合疼痛以及咬合伴过敏性冷热刺激痛的患者,而对于咬舍伴延续性冷热刺激疼痛的患者则宜先行根管治疗术再进行全冠修复。