Biochemical changes in periodontal ligament ground substance associated with short-term intrusive loadings in adult monkeys (Macaca Fascicularis).

Proteoglycan-like fractions (PG) were isolated from the ligaments of teeth undergoing various degrees of intrusive loadings. The PG were characterized by their molecular-size profiles on Sepharose 4B, the presence of uronic acid in the separated fractions and by the electrophoretic detection of constituent glycosaminoglycans including heparan sulphate, hyaluronic acid, dermatan sulphate and chondroitin-4-sulphate. The high molecular-weight fraction, peak i (estimated minimum size, 2 X 10(6) daltons) of the normal-functioning (stressed) ligament was reduced approx. 70 per cent, compared with ligament undisturbed for 3 h. There was a decrease in peak-i size between 0.25 and 1 N loadings of approx. 72 per cent. The 4 N loadings produced a further decrease followed by an increase during a 3 h undisturbed recovery phase. Thus changes in the chemistry and properties of the ground-substance components of the periodontal ligament could partly explain changes in tooth mobility.