Temporal nature of periradicular bands ('Striae periradicales') on mammalian tooth roots.

Temporal nature of periradicular bands ('Striae periradicales') on mammalian tooth roots.
Front Oral Biol. 2009;13:86-92
Authors: Smith TM, Reid DJ
Abstract
Periradicular bands, or fine circumferential lines on tooth roots, have received attention recently due to their prominence on hominin fossils and their potential utility for informing studies of root formation. In 1938, Komai and Miyauti [Dtsch Zahn Mund Kieferheilkd 1938;5:791-795] demonstrated that periradicular bands are related to dentine growth rather than cementum, suggesting that they were equal to accentuated lines in dentine ('dentine lamellae' or 'contour lines'). More recent indirect evidence from band spacing on primate roots suggests that they are temporally equal to other long-period lines in enamel (Retzius lines, perikymata) and dentine (Andresen lines). One of the main complications in understanding the relationship between Andresen lines and periradicular bands is the layer of cementum found on erupted teeth, which often obscures bands. Here we present both direct and indirect evidence that periradicular bands are temporally equivalent to internal long-period lines in the enamel and dentine. A sample of modern human teeth showing periradicular bands and accentuated rings was externally notched, molded, and sectioned; in one instance it was possible to show an equal number of long-period lines (internal Andresen lines and external periradicular bands) between is...

Source: Frontiers of Oral Biology - November 25, 2014 Category: ENT & OMF Tags: Front Oral Biol Source Type: research