Effect of cyclophosphamide on dentinogenesis in the rat incisor: fluorescence microscopic and microradiographic investigations.

Previously described dentin reactions to cyclophosphamide (CPhA) were studied by means of fluorescent labeling and microradiography. Ten adult rats received 20 mg/kg calcein i.p. on days 0, 4, 7, 10, and 40 mg/kg CPhA 30 min after the first calcein injection. Two animals served as controls. The observation time was 14 d. Fluorescence microscopy and microradiography of the maxillary incisors revealed 1)niche-like defects in dentin starting in mineralize 1-4 d after the CPhA administration labially, while lingually the niches developed later and were completed earlier, 2)localized reduced and increased growth lingually, 3)continuous but reduced apposition of a hypomineralized dentin in the niches, and 4)niche osteodentin produced by pulp cells.