Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of th...

Witter K. , I . Mí‰ek: Time Programme of the Early Tooth Development in the Domestic Sheep (Ovis aries, Ruminantia). Acta Vet. Brno 1999, 68: 3-8. The knowledge of a generally valid pattern of odontogenesis is a prerequisite for the identification of diseases and developmental anomalies in the oral cavity of domestic animals and man. The sheep is a very interesting model species for the investi...

Recently we reported ultrastructural observatlons which indicated that matrix vesicles were actual constituents of the intercellular organic matrix during embryonic tooth development (14). It is assumed that many of these matrix vesicles are involved in formative aspects of dentinogenesis or amelogenesis, two primary extracellular processes that occur during embryonic tooth formation The fracti...

Sonic hedgehog (Shh) is an essential signaling peptide required for normal embryonic development. It represents a highly-conserved marker of odontogenesis amongst the toothed vertebrates. Signal transduction is involved in early specification of the tooth-forming epithelium in the oral cavity, and, ultimately, in defining tooth number within the established dentition. Shh also promotes the morp...

Osteogenesis imperfecta (OI) is an inherited disorder of collagen which might manifest in dentin. OI is due to a collagen mutation where glycine is substituted by larger amino acids disturbing collagen fibril coiling. The defect collagen might impair dentin mineralization. As OI is a collagen disturbance, a majority of publications has focused on the organic components of tissues. The inorganic...

``Osteogenesis imperfecta'' and ``vitreous osteoporosis'' are genetic diseases in most of their cases, that is, it is sufficient for one the parents to be a disease carrier order have children suffering from it. It main protein source bone structure leading this disorder; however, factor common accounts about 80 85% causes osteogenesis imperfecta. The congenital disorder associated with defect ...

Amelogenesis imperfecta (AI) is a group of inherited disorders characterized by abnormal enamel formation. This article outlines the treatment aspect for rehabilitation of occlusion using telescopic overdenture for a patient having amelogensis imperfecta.

osteogenesis imperfecta is a rare inherited connective tissue disorder with an expression that varies from mild to severe disease affecting bone, sclera and middle ear. fertility is preserved, especially in those patients with type 1. we present hereby a pregnant woman with osteogenesis imperfecta that had over 30 fractures in long bones and vertebrae. the object of this report was to determine...

Most patients with dominantly inherited osteogenesis imperfecta have blue sclerae and relatively mild symptoms. However, in a small group of families the patients have normal sclerae and this disorder has been classified as Type 4 osteogenesis imperfecta. This paper reports the clinical and radiographical features of 48 patients from 16 families with Type 4 osteogenesis imperfecta and compares ...

Osteogenesis imperfecta is an incurable genetic disorder manifested with altered bone quality that predisposes patients to a multitude of fractures throughout their lives, including acetabular fractures. The management of acetabular fractures in patients with osteogenesis imperfecta remains a challenging clinical problem, with a paucity of literature supporting treatments and their outcomes. Li...