The structure of the cemento-dentinal junction in rat molars

The cemento-dentinal junction was observed in the acellular and cellular ce mentum of rat molars by light and scanning electron microscopy. Scanning el ectron microscopy, combined with NaOH maceration, was used to observe the f ibrous architecture directly in this region. Light microscopy revealed that the cemento-dentinal junction contains fewer collagen fibrils and more pro teoglycans than the cementum and dentin. Scanning electron microscopy also showed that fibril intermingling is found only in some regions of the fibri l-poor junction in macerated specimens. Prolonged maceration breaks down th e cemento-dentinal junction in spite of the fibril intermingling. Only mace rated specimens showed detachment here. It was established that NaOH macera tion removes interfibrillar substances effectively, and does not damage the fibril structure or architecture. This suggests that the adhesion of prote oglycans is more important than fibril intermingling for preserving the cem ento-dentinal attachment in the rat molar.