RME-induced root resorption and repair: a computerised 3-D reconstruction.

This study was designed to evaluate the 3-D relation of epithelial rests of Malassez (ERM) to orthodontically induced resorption lacunae in human tooth roots. First premolars were extracted following rapid maxillary expansion, then they were prepared for transmission electron microscopy and sectioned. Serial 1 micron sections were used for the 3-D reconstructions and ultra thin sections were utilized to verify the identification of epithelial cells and blood vessel types. Each serial section was photographed and profiles of the resorption bays, epithelial cells and blood vessels were digitized and computer reconstructions performed with an IBM-based software programme. The reconstructions supported the view that epithelial cell and blood vessel relation to the resorption lacunae appeared to be related to the level of activity of the bay. Possible functional roles for epithelial cells in the resorptive process are discussed.