U. Kierdorf et al., LIGHT AND SCANNING ELECTRON-MICROSCOPIC I NVESTIGATIONS ON ENAMEL HYPOPLASIAS OF FLUOROSED ROE DEER TEETH, Zeitschrift fur Jagdwissenschaft, 40(3), 1994, pp. 175-184
Hypoplastic enamel surface lesions were studied in severely fluorosed
permanent mandibular cheek teeth. The shape of the hypoplasias varied
between large, rather shallow depressions of the enamel surface and na
rrow lesions running deep into the enamel. The areas of transition bet
ween hypoplasias and surrounding enamel were of a convexly rounded out
line. Studies of thin ground sections through hypoplasias viewed in no
rmal and polarized light showed the (crowded) Retzius lines to exactly
follow the shape of the hypoplastic surface lesions. As was revealed
by scanning electron microscopy, the bottom of the shallow defects as
well as the walls of the lesions and the transitional area between hyp
oplasias and surrounding surface enamel were covered by Tomes' process
pits. Based on the present findings and that of a previous study (KIE
RDORF et al. 1993), we interprete these enamel surface hypoplasias to
be the result of a more or less intense reduction in the secretory act
ivity of the ameloblasts. On the basis of our observations, detachment
of the ameloblasts from the forming enamel surface and formation of s
ubameloblastic cysts, that were observed in rodents after injection of
high doses of fluoride, can be excluded as the way by which formation
of the hypoplasias described in this study had occurred.