Investigation of Structure of Dentin Formative Disturbances Caused by Antineoplastic Agents

• Published in: Journal of Hard Tissue Biology 2007, Vol.16(3), pp.131-138
• Main Authors: Miake, Yasuo, Katakura, Akira, Moriguchi, Mitsuko, Yamaguchi, Yasuaki, Yanagisawa, Takaaki
• Format: Article
• Language: English
• Subjects: Dentin; Formative disturbance; Rat incisor; Vinblastine
• ISSN: 1341-7649; 1880-828X
• DOI: 10.2485/jhtb.16.131

In this research, we aimed to clarify change of old odontoblasts as well as mineralization level of formative disturbances line upon administration of antineoplastics. Male Wistar rats weighing 100 g were given injection of 2 mg/kg of Vinblastine (VBL). 1, 3, 5, 7, and 14 days after the administration, perfusion fixation was performed and upper incisors were removed. Then specimens with and without demineralization were embedded in epoxy resin and were observed by light microscopy, contact microradiography and transmission electron microscopy. At 1 day after the administration, necrosis of many old odontoblasts, abnormality of direction of collagen secretion and plenty of collagen fibers deposition were seen. Detection of this alteration at even 7 days after the administration suggested that disorder of secretion function associated with microtubule abnormality continues for a long period. The collagen secreted after VBL administration did not contribute increase of thickness and density of the predentin collagen formed before the drug injection and was deposited extremely dense along distal end of the cells. Thus the original predentin remained with low collagen density and a wide interfibrillar space. Regarding with mineralization process of formative disturbances line, density of collagen fibers was extremely low with thick needle shaped crystals in hypermineralization layer, and the density was oppositely very high with small crystals in hypomineralization layer. Although irregular dentin formed at medial side of formative disturbances line increases with time, mineralization degree is very low. The reason for this phenomenon was considered not only due to embedment of vessels and cellular particles but also observation of an unmineralized region around thick dentinal tubule, thus resulting in a decrease of general mineralization level.