A comparative study of translucent apical dentine in vital and non-vital human teeth.

Previous studies have shown that dentinal apical translucency increases with age. Although the mechanism by which apical translucency is produced is still uncertain, it has been suggested that it develops at a slower rate in non-vital teeth. In this investigation the amount and distribution of apical translucent dentine in a group of age-matched vital and non-vital teeth were compared. Fifty-five non-vital (root-filled) teeth and 49 vital teeth were used. Freshly extracted teeth were fixed in 2% glutaraldehyde solution, sectioned longitudinally in the buccolingual plane and ground to a thickness of 150 microns. Each section was photographed in polarized light at a standard magnification against a ruled scale background. Black-and-white prints of standard magnification were produced and translucent apical dentine was plotted using an Apple II digitizer. Variables measured were length, length as a percentage of root length, area and area as a percentage of root area. Data were related to age and tooth type and analysed by Mann-Whitney and regression analysis. Significant differences (p < 0.05) were present when tooth types were pooled. There was more apical translucency present in all types of non-vital teeth when compared with vital teeth at any given age.