[Applications of collagen extrafibrillar demineralization in dentin bonding].

The existing dentin bonding systems based on acid-etching technique lead to the loss of both extrafibrillar and intrafibrillar minerals from dentin collagen, causing excessive demineralization. Because resin monomers can not infiltrate the intrafibrillar spaces of demineralized collagen matrix, degradation of exposed collagen and resin hydrolysis subsequently occur within the hybrid layer, which seriously jeopardizing the longevity of resin-dentin bonding. Collagen extrafibrillar demineralization can effectively avoid the structural defects within the resin-dentin interface caused by acid-etching technique and improve the durability of resin-dentin bonding, by preserving intrafibrillar minerals and selectively demineralizing extrafibrillar dentin. The mechanism and research progress of collagen extrafibrillar demineralization in dentin bonding are reviewed in the paper.

[A pathologic study of the vagus nerves in diabetes mellitus].

A systematic morphometric examination at different levels of the vagus nerves obtained at autopsy in 4 control subjects and 3 diabetics was carried out. Morphometric studies on myelinated fibres were performed on the nerve at mid-cervical, lung hilum and diaphragmatic levels. In 2 insulin-dependent diabetics the density of myelinated fibres was below the lower limit of the control range at all levels. In all the diabetic subjects there was significant reduction in the density of fibres at the most distal level in the nerves. The teased fibre studies showed predominantly changes of axonal degeneration. They are consistent with the findings of abnormal vagal function in diabetics.