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M T Cobourne

Publications and source records attributed to M T Cobourne.

6 recordsLinked to original sources
PubMed2002

Analysis of the morbidity of submerged deciduous molars: the use of imaging techniques.

A case is presented of a 13-year-old patient who had a class I occlusion on a class I skeletal base but with a retained and submerged deciduous molar causing impaction of the second premolar. Diagnostic imaging illustrates the potential challenges of the removal of the retained deciduous molar. Magnetic resonance imaging used to identify the path of the inferior alveolar neurovascular bundle clearly delineates its intimate association with the impacted teeth and underscores the risk of trauma during extraction. This is discussed with regard to other cases of submerged molars, and a strategy is outlined.

Adolescent↗
PubMed2001

Sonic hedgehog regulates epithelial proliferation and cell survival in the developing tooth germ.

Shh expression is highly restricted to the future sites of tooth development during the initiation of odontogenesis. This suggests a role for Shh as a proliferative factor, as localized epithelial thickenings invaginate to form a tooth bud. We have investigated this role by blocking Shh signaling between E10.5 and E12.5 in murine mandibular processes using a 5E1 blocking antibody and the PKA activator Forskolin. This results in down-regulation of Ptc, a principle target of Shh signaling. The effects of inhibition varied with developmental time. At E10.5, tooth development was arrested as epithelial thickenings and the numbers of teeth developing were considerably reduced. Inhibition at E12.5 produced localized apoptosis in the epithelium at the tip of the tooth buds, although some teeth were able to develop. Thus, Shh has dual roles in early odontogenesis, first in bud formation by stimulating epithelial proliferation, and second in the development of cap-stage tooth germs by increasing epithelial cell survival.

Animals↗
PubMed2000

Construction for the modern head: current concepts in craniofacial development.

The vertebrate head is a highly complex composite structure whose morphological characteristics are controlled at the level of the gene. There is now increasing evidence for the role of gene families that encode transcription factors in determining the embryonic plan of the developing craniofacial complex. These genes act as regulators of gene transcription being intimately involved with the control of complex interactions between multiple downstream genes. Combinatorial expression of the Hox genes (a family of highly conserved master regulatory genes related to the homeotic genes of the fruitfly Drosophila) have been shown to play a definitive role in patterning distinct regions of the craniofacial complex. In the vertebrate, Hox genes pattern the hindbrain and branchial regions of the developing head up to and including structures derived from the second branchial arch. The first branchial arch and more rostral regions of the head are patterned by groups of homeobox genes more diverged from the original Hox clusters. Transgenic mice, with targeted disruptions in many of these genes, are now providing insights into the molecular mechanisms that lie behind a number of craniofacial defects seen in man.

Animals↗
PubMed1996

An unusual dental cause of nasal discharge: a case report.

A case is reported of an unusual cause of localized nasal discharge. A 6-year-old girl presented complaining of pain and discharge from the left nostril. Clinical and radiological evaluation revealed the cause of the symptoms to be a previously asymptomatic intruded primary incisor on the floor of the nasal cavity. The tooth was removed under general anaesthesia and healing occurred without complication.

Child↗