Search

Cementum crystals and matrix vesicles on the root surface of partially formed teeth in dogs were examined with a transmission electron microscope. Fine filamentous crystals were observed in the cementum calcifying fronts. The running pattern was mainly parallel to the root surface in the apical region and perpendicular to the root surface in lateral and coronal regions. Matrix vesicles were observed at the apical half of the periodontium, but not observed at the coronal region. These findings suggest that the parallel-arranged cementum would become the light-microscopic lamellar type and the perpendicular one the light-microscopic dense-line structure when fully developed. Moreover, cementum formation occurs due to two kinds of mechanisms: participation of matrix vesicles and secondary calcification (= additional cementogenesis).

Seventeen patients treated for acute lymphoblastic leukemia by combination chemotherapy before their reaching 10 years of age were studied for altered dental root development of their premolar teeth. Five of the 17 patients showed subjective radiographic evidence of marked shortening of the premolar dental roots; 13 had thinning of the roots. A quantitative analysis was developed and verified, which disclosed a 63.33% to 84.38% reduction of premolar root length when compared with the mean of the historical controls. With recent significant increases in long-term survival rates of children with malignancies, altered dental development becomes an important factor to follow years after chemotherapy is discontinued. The findings of these chemotherapy-associated dental development changes impacts on the patient's quality of life and also can serve as a research tool to assess permanent effects of chemotherapy on normal tissue growth and development.