A SCANNING ELECTRON AND CONFOCAL LASER MICROSCOPE INVESTIGATION OF TETRACYCLINE-AFFECTED HUMAN DENTIN

Because of the well reported dental side-effects of tetracycline admin istration, the drug should not be administered to children. However, i t and its derivatives are often administered over a prolonged period f or treatment of acne in young adults. Dental side effects are also not iced in these patients. The aim of this study was to examine with scan ning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) the root dentine of a tooth From a young adult affected by terr acycline therapy. The palatal root of an upper third molar, demonstrat ing distinct areas of tetracycline staining, tvas removed from the cro wn and sectioned longitudinally to produce two samples. The pulp tissu e was peeled off the dentine and any remaining non-mineralized tissues were removed with sodium hypochlorite. One sample was prepared for SE M and the other as a ground section which was examined with a CLSM. It was demonstrated by SEM that the mineralizing front of unaffected den tine was of a normal calcospherite appearance; in contrast, the minera lizing front of the tetracycline-affected dentine was devoid of calcos pherite formation and many surface defects were apparent. In addition, the number of dentinal tubules associated with the defects was reduce d. It was shown by CLSM that tetracycline bands were made up of numero us smaller bands and that peritubular dentine not associated with fluo rescent bands had incorporated tetracycline. The CLSM examination of t he mineralization front of the affected dentine revealed that fluoresc ence of dentine was restricted to the peritubular dentine. The results confirm that dentine mineralization is affected by systemic tetracycl ine therapy and that tetracycline can be incorporated into peritubular dentine after mineralization of the primary dentine matrix.