Anterior mandibular displacement and condylar growth. An experimental study in the rat

Journal Article · Fri Oct 01 00:00:00 EDT 1982 · Am. J. Orthod.; (United States)

DOI:https://doi.org/10.1016/0002-9416(82)90462-6· OSTI ID:5994424

Tonge, E A; Heath, J K; Meikle, M C

Anterior displacement of the mandible was produced in twenty-eight 1-month-old female rats by two methods: (1) cast-gold splints cemented to the maxillary incisor teeth and (2) a removable stainless steel mesh appliance worn 6 hours each day, during which time the animals were sedated. The controls were littermates without appliances and in the mesh group were also sedated. Animals in the splint group were killed after 24 hours, 1 week, and 1 month; those in the mesh group were killed after 24 hours and after 1 week. the condyles were removed and cultured for 24 hours in medium containing /sup 3/H-thymidine. One condyle from each animal was processed for routine histologic and autoradiographic study. The other was digested in phosphate-buffered saline containing RNA-ase and pronase, and the specific activity of /sup 3/H-thymidine incorporation expressed as dpm/microgramDNA. Anterior mandibular displacement produced by both methods failed to result in a significant increase in the incorporation of /sup 3/H-thymidine into explant DNA. In the 7-day mesh experiment, however, there was a significant increase in the DNA content of the condylar explants from the displacement group, suggesting an increase in the cell population. This finding should be treated with caution because of the small numbers of animals involved, but it indicates an important area for further study. Changes in the distribution of labeled cells within the proliferative zone (PZ) were also observed autoradiographically in the mesh group, but there was little to suggest that mandibular displacement was accompanied by a significant increase in cell division within the PZ. Remodeling changes affecting both the articular tissue and the subchondral bone were a characteristic feature of the 1-month bit plane group.

• Research Organization: Department of Orthodontics, Eastman Dental Hospital and Institute of Dental Surgery, University of London, England
• OSTI ID: 5994424
• Journal Information: Am. J. Orthod.; (United States), Vol. 82:4
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
JAW
AUTORADIOGRAPHY
MALFORMATIONS
BIOCHEMISTRY
CARTILAGE
DNA
RATS
THYMIDINE
TISSUE CULTURES
TRITIUM COMPOUNDS
ANIMAL TISSUES
ANIMALS
AZINES
BODY
CHEMISTRY
CONNECTIVE TISSUE
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
MAMMALS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PATHOLOGICAL CHANGES
PYRIMIDINES
RIBOSIDES
RODENTS
SKELETON
SKULL
TISSUES
VERTEBRATES
550801* - Morphology- Tracer Techniques