Estudo morfometrico ultraestrutural da matriz extracelular do ligamento periodontal do incisivo inferior de ratos, em diferentes regioes e zonas, nas condições de erupção impedida, desimpedida e retardada pela vimblastina

AUTOR(ES)

Silvana Pereira Barros

DATA DE PUBLICAÇÃO

1995

RESUMO

The area density of collagen fibrils and interfibrilar ground substance as well as the collagen fibrils diameter were detennined at the ultrastructurallevel in several regions and zones of the periodontal ligament of impeded and unimpeded rat incisors with eruption retarded by vimblastine. Six male rats hàd their lower left incisor kept in an unimpeded eruption condition while the contralateral one erupted nonnally. Three of these animaIs received an intraperitoneal injection of vimblastine (2 mg/Kg body weight) 24 hours before the end of the experiment, one week later. The other three animaIs received an equivalent volume of saline solution. The teeth were divided in 5 regions transversal to the longitudinal axis of the mClsor and processed for transmission electron microscopy. For each zone of the periodontalligament (tooth-related, bone-related and a midle one between the two), at the mesial face of the 5 regions 3 eletronmicrographs were printed at a final magnification of X 73.700, each micrograph presented more thaii 50% of its area of collagen fibrils in cross section. A test lattice with 400 points was used to detenninate the relative areas of collagen fibrils and interfibrilar ground substance and in each electronmicrograph the diameter of 30 collagen fibrils was measured. Data were submitted to statistical analysis using: variance anlysis, Tukey s test, response surface regression and canonical analysis. In both groups, in either impeded or unimpeded eruption, the mean diameter of collagen fibrils in alveolar bone zone was larger than in the others two zones. The unimpeded teeth from thecontrol group presented fibrils with a lower collagen fibril mean diameter than impeded ones. Generally the opposite was found in vinblastine-treated group, characterizing an interaction with reverse values. The response surface regression showed diameters values decreasing from region number 3 (related to lower first molar) toward the incisal and apical regions, while an increase of such values from a strip of the dental zone towards the alveolar zone and the remaining of the dental related zone. That pattem was different only in unimpeded teeth of vinblastine-treated animaIs, where the mean collagen diameter increased in both, apical and incisal, directions from region 3. The area occupied by interfibrilar ground substance was generally greater than the area of collagen fibrils in unimpeded teeth of the control group, while the contrary occured in the vinblastine-treated group. These differences seem to indicate that the choice of the region or zone of the periodontal ligament to be analysed, in relation to the effects of altered eruption or mechanical conditions of the incisors, may interfere on the results

ASSUNTO(S)

microscopia eletronica periodontia

Documentos Relacionados

• Efeitos da erupção alterada, por desimpedimento e pela vimblastina, nos fibroblastos de regiões e compartimentos do ligamento periodontal de incisivos de ratos, estudo morfometrico ultraestrutural
• Estudo histomorfometrico do ligamento periodontal de incisivos de ratos em erupção impedida e desimpedida
• Estudo morfometrico dos compartimentos de varias regiões do ligamento periodontal de incisivos de ratos em condições de erupção alterada pelo desimpedimento e pela vimblastina
• Biossintese de proteinas do ligamento periodontal de incisivos de camundongos em erupção desimpedida e retardada pela vimblastina : estudo radioautografico atraves da incorporação de 3H-glicina
• Avaliação estereologica ultraestrutural das densidades volumetricas dos fibroblastos e do colageno do ligamento periodontal do incisivo de rato em condições funcionais alteradas