Twisted plywood structure of an alternating lamellar pattern in cellular cementum of human teeth

Human cellular cementum was examined by scanning electron microscopy to elu cidate the manner of the alternate lamellar pattern forming the cellular ce mentum. Specimens were demineralized, trimmed with a freezing microtome, an d treated by NaOH-maceration. This procedure was chosen to avoid artifacts in the fibril arrangement, and to study the fibrous architecture in detail. For comparison, non-demineralized, polished and HCl-etched specimens were also prepared. In the NaOH-macerated specimens, the lamellar pattern of the cellular cementum conformed to the twisted plywood principle of bone lamel lation with a periodic rotation of matrix fibrils resulting in an alternati ng lamellar pattern. In contrast, matrix fibrils were irregularly arranged without indication of rotation of matrix fibrils in the polished and etched specimens. Our results suggest that polishing and etching procedures cause damage to fibrils and fibril arrangement.