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Ultrastructural vascular changes in pressure zones of rat molar periodontium incident to orthodontic movement
Author(s) -
RYGH PER
Publication year - 1972
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.1972.tb00296.x
Subject(s) - periodontal fiber , ultrastructure , periodontium , molar , chemistry , fragmentation (computing) , anatomy , electron microscope , dentistry , biology , medicine , ecology , physics , optics
– Changes in the vasculature of the periodontal ligament of teeth subjected to orthodontic forces have been described. The purpose of the present study was to characterize these changes at the ultrastructural Ievel. In 55 rats, one maxillary first molar was moved buccally by means of a fixed appliance, using forces of 5–25 g. Animals were sacrificed after periods of 30 min to 28 d. The experimental teeth with surrounding periodontal tissues were obtained and processed for electron microscopy. Retardation and stasis of the blood flow occurred within 30 min after force application. After 2 h the vessels in the pressure zone appeared extended and packed with red blood cells which often attained a polygonal shape. After 2 h to 3 d, fragmentation of the erythrocytes occurred. Various patterns of erythrocyte breakdown were observed. Most often the erythrocytes changed into irregularly contoured fragments of various electron densities. Occasionally the fragments exhibited a substructure indicating transformation to a crystalline substance. Also, disintegration of the walls of the blood vessels and release of their contents into the surrounding fibrous tissue was observed after 1–7 d. Regenerative processes were predominating in the 7–28 day specimens.