Conservation of early odontogenic signaling pathways in Aves.
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Teeth have been missing from birds (Aves) for at least 60 million years. However, in the chick oral cavity a rudiment forms that resembles the lamina stage of the mammalian molar tooth germ. We have addressed the molecular basis for this secondary loss of tooth formation in Aves by analyzing in chick embryos the status of molecular pathways known to regulate mouse tooth development. Similar to the mouse dental lamina, expression of Fgf8, Pitx2, Barx1, and Pax9 defines a potential chick odontogenic region. However, the expression of three molecules involved in tooth initiation, Bmp4, Msx1, and Msx2, are absent from the presumptive chick dental lamina. In chick mandibles, exogenous bone morphogenetic protein (BMP) induces Msx expression and together with fibroblast growth factor promotes the development of Sonic hedgehog expressing epithelial structures. Distinct epithelial appendages also were induced when chick mandibular epithelium was recombined with a tissue source of BMPs and fibroblast growth factors, chick skin mesenchyme. These results show that, although latent, the early signaling pathways involved in odontogenesis remain inducible in Aves and suggest that loss of odontogenic Bmp4 expression may be responsible for the early arrest of tooth development in living birds. (+info)
Congenital hydrocephalus associated with congenital glaucoma and natal teeth.
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We report the first described association of natal teeth with congenital hydrocephalus and congenital glaucoma, anterior segment dysgenesis with non-attachment of the retina. The clinical findings support a diagnosis of Walker-Warburg syndrome. The forkhead 7 transcription factor gene is proposed as a candidate gene for this syndrome. (+info)
Sublingual traumatic ulceration due to neonatal teeth (Riga-Fede disease).
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The term Riga-Fede disease has been used historically to describe traumatic ulceration that occurs on the ventral surface of tongue in neonates and infants. It is most often associated with natal and neonatal teeth in newborns. A case of Riga-Fede disease is presented. (+info)
Residual neonatal teeth: a case report.
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A case is presented in which an infant required extraction of 2 residual neonatal teeth. Some authors suggest routine curettage of the extraction sites of natal and neonatal teeth to prevent the development of residual teeth. In light of the rare occurrence of such residual teeth, this may represent overtreatment. Curettage at the time of extraction is recommended only in cases where the administration of an injectable local anesthetic is required because of greater gingival attachment. (+info)
Natal teeth: a review.
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The incidence of natal teeth is approximately 1:2,000 to 1:3,000 live births. The most commonly affected teeth are the lower primary central incisors. Natal teeth usually occur in pairs. The eruption of more than two natal teeth is rare. The majority of natal teeth represent the early eruption of normal primary deciduous dentition. Less than 10% of natal teeth are supernumerary. Natal teeth might resemble normal primary dentition in size and shape; however, the teeth are often smaller, conical and yellowish, and have hypoplastic enamel and dentin with poor or absent root formation. Complications include discomfort during suckling, sublingual ulceration, laceration of the mother's breasts and aspiration of the teeth. A dental roentgenogram is indicated to differentiate the premature eruption of a primary tooth from a supernumerary tooth. Tooth extraction is indicated if the tooth is supernumerary or excessively mobile. If the tooth does not interfere with breastfeeding and is otherwise asymptomatic, no treatment is necessary. (+info)
Unusual neonatal tooth in maxillary 1st molar region: a case report.
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Teeth erupting within the first month after birth are known as neonatal teeth. Incidence of neonatal teeth is very low. Neonatal teeth erupt in various regions of the maxillary and mandibular arch. Incidence of neonatal teeth in molar region is only 1%. A case of an unusual neonatal tooth in the maxillary molar region has been presented. (+info)
Ellis-van Creveld syndrome: a case report.
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Ellis-van Creveld syndrome (EvC) is a disease complex, where all the three embryonic layers appear to be involved. This disorder is also called as Chondroectodermal dysplasia. EvC is an autosomal recessive disorder resulting from mutations in these patients. Mutations in the two genes EVC and EVC2, have been identified to cause the condition. It has been considered as a skeletal dysplasia with an incidence of approximately 1 out of 1,50,000 live births. A high prevalence has been reported among certain populations like Amish and Arabs of Gaza strip. There are more than 300 cases of EvC reported into the literature. About 50-60% of cases have been reported with congenital cardiac malformations. (+info)
Natal primary molar: clinical and histological aspects.
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The authors report a case of natal primary molar in a healthy 14-day-old child. The diagnosis of the case and the treatment plan are discussed, as well as histological analyses of the natal tooth. The tooth presented an immature appearance, with high mobility and insertion only in soft tissue, and therefore the clinical option adopted was dental extraction. Histological analyses revealed enamel hypoplasia and dentin showing a typical tubular pattern without alterations. The soft tissue had young and richly vascularized pulp with areas of chronic inflammatory infiltration. (+info)