One of the goals of the management of the developing occlusion and the correction of malocclusion is the establishment of symmetry within the individual arches (arch form) and the occlusal relationships between the maxillary and mandibular arches. The symmetry in arch form is related to the axial inclinations and rotations of the individual teeth. The occlusion is affected not only by the positions of the teeth, but also by the patterns of skeletal growth.
View Article and Find Full Text PDFX-Linked hypohidrotic ectodermal dysplasia (XLHED) is a human congenital disorder resulting in abnormal tooth, hair and sweat gland development. A candidate gene for the disorder has been cloned, but the function and full size of its putative protein product is unclear. We have identified a candidate cDNA for the mouse Tabby gene (Ta), which, based on phenotype and syntenic mapping, is postulated to represent the analogous murine disorder.
View Article and Find Full Text PDFHedgehog genes are involved in pattern formation during embryonic development. A recent report showed that Sonic hedgehog is expressed in the mouse mandible in the presumptive incisor region. In the present study, Indian hedgehog (Ihh) transcripts were present from gestational day 9 to 14 in the mouse mandible (reverse transcription/polymerase chain reaction analysis).
View Article and Find Full Text PDFHedgehog genes have recently been implicated in the control of pattern formation in many developing organ system. Vertebrate homologues of the Drosophila hedgehog have been identified in mouse and rate embryos. The temporal regulation of sonic hedgehog (mouse homologue) has previously been studied by Northern analysis of whole embryos with varying results.
View Article and Find Full Text PDFEndogenous retinoids are present in the embryonic mouse mandible and reach a concentration peak immediately before the formation of the dental lamina. Because exogenous retinoids alter the pattern of the dental lamina and the expression of epidermal growth factor mRNA (a transcript necessary for initiation of odontogenesis), the role of retinoic acid in the initiation of odontogenesis was studied here. Citral (3,7-dimethyl-2,6-octadienal), a known inhibitor of retinoic acid synthesis, was used to block the endogenous synthesis of retinoic acid in the mouse embryonic mandible before the formation of the dental lamina (gestational day 9).
View Article and Find Full Text PDFEndogenous retinoids are present in the embryonic mouse mandible and reach a peak in concentration at the time of the formation of the dental lamina. All-trans retinoic acid is present in a 10-fold higher concentration in the future incisor region of the mouse embryonic mandible at day 11.5.
View Article and Find Full Text PDFThe initiation of odontogenesis is characterized by the site-specific proliferation of mandibular epithelium in the formation of the dental lamina. The epidermal growth factor (EGF) gene is expressed in the developing mandible immediately before the appearance of the dental lamina. This expression is necessary for the formation of the dental lamina and subsequent development of teeth.
View Article and Find Full Text PDFArch Oral Biol
December 1994
Retinoids play an important part in pattern formation during embryonic development. Exogenous retinoids alter the pattern of skeletal, neural and odontogenic tissues. Endogenous retinoids have been demonstrated previously in the murine embryonic mandible, reaching a concentration peak during the initiation of odontogenesis.
View Article and Find Full Text PDFRetinoids have important roles in pattern formation during embryonic development and might act as endogenous morphogens. They are necessary for normal odontogenesis and excess retinol alters the pattern of odontogenesis producing supernumerary buds of the dental lamina in the diastema region of the mouse mandible. Because the metabolism of retinoids in the developing mandible is unknown, the effects of retinal (an intermediate metabolite in the local conversion of retinol to retinoic acid) on the patterning of odontogenesis were examined.
View Article and Find Full Text PDFArch Oral Biol
September 1994
Retinoids play an important part in embryonic pattern formation. They are necessary for normal differentiation of odontogenic tissues and, in excess, disrupt the pattern of tooth formation. Excess retinoids produce supernumerary buds of the dental lamina in the diastema region of the mouse embryonic mandible where teeth do not normally form.
View Article and Find Full Text PDFDevelopment of the mouse embryonic mandible from days 9 to 14 involves tissue interactions in the formation of bone, cartilage, salivary glands and teeth. Growth factors may play an important role in these interactions. Epidermal growth factor (EGF) mRNA expression has been characterized and its presence has been shown to be necessary for odontogenesis.
View Article and Find Full Text PDFRetinoids alter the patterning of murine odontogenesis in vivo and stimulate epithelial proliferation. Because odontogenesis is dependent on proliferation of mandibular epithelium, the effects of retinol on the patterning of odontogenic epithelium were studied. These experiments control for developmental stage, applied retinoid concentration and duration of exposure.
View Article and Find Full Text PDFThe initiation of odontogenesis depends on the site-specific proliferation of mandibular epithelium beginning at Day 11 in embryonic mice. We have previously reported that the local expression of epidermal growth factor mRNA in the murine mandible is developmentally regulated, expressed at Days 9 and 10 immediately prior to the initiation of tooth bud formation at Day 11. Exposure of Day 9 mandibular explants to antisense oligomers of epidermal growth factor blocks the initiation of odontogenesis.
View Article and Find Full Text PDFArch Oral Biol
October 1991
Reverse transcription and cDNA amplification (polymerase chain reaction) of total RNA preparations were used to characterize the expression of EGF mRNA in the mandibular arch of day 9-17 mouse embryos. EGF mRNA was present in mandibles at day 9 and 10 but not at days 11-17. Separate RNA preparations from epithelium and mesenchyme at day 10 revealed EGF mRNA in both components.
View Article and Find Full Text PDFThis study set out to determine the average patient's age at initial detection of interproximal caries for individual posterior tooth surfaces. Ninety-six patients between the ages of 2 and 14 years were followed longitudinally over a series of periodic oral examinations. The average patient's age at initial detection of interproximal caries ranged from 6.
View Article and Find Full Text PDFPediatricians and family physicians can play a significant role in the initiation of dental care for preschool children because they are seen more often by a physician than a dentist. The Committee on Standards for Child Health Care of the American Academy of Pediatrics recommends inspection of the mouth, teeth, and gums at every pediatric visit. This article describes the oral tissues in health and in disease as well as the role physicians can play in preventive dental care.
View Article and Find Full Text PDFOne area of particular concern, on behalf of the pediatric dental patient, is the routine use of low doses of ionizing radiation in the form of bitewing radiographs at semi-annual examinations. Patients at high-risk for interproximal caries should receive bitewing examinations at the first clinical evidence of caries. The use of pit and fissure caries as a criterion for determining relative interproximal caries risk may not be reliable in fluoridated communities.
View Article and Find Full Text PDFWith 1,153 pairs of bitewing radiographs representing data collected from 145 patients, we determined that the average positive bitewing interval was 17.7 months, which is consistent with published recommendations of 12- to 24-month intervals.
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