The goal of our research is to determine the functional significance of interspecies differences in structural features of amelogenesis in order to better understand how to enhance sound enamel formation and eliminate pathology in humans. Mammalian amelogenesis is a unified process with temporal and spatial displacement of some component events of that process among various species. That is, interspecies heterogeneity observed in amelogenesis represents variations on a common theme. Amelogenesis has been segmented into three major stages; presecretory, secretory, and maturation (or resorptive), each of which is readily discernible in all mammalian tooth buds. These stages refer solely to enamel matrix proteins, but not necessarily to exclusive functions of ameloblasts or other cells of the enamel organ at any specific stage. We propose to test the hypothesis that within each of the three stages secretion and resorption occurs. In contrast to rodents, animals whose teeth form rapidly, specific events in amelogenesis of cats are very clearly defined in time and space. Consequently this is the model proposed here. Of particular importance to this study are the putative secretory and resorptive functions of ameloblasts in the presecretory stage, pharmacologically altered secretion, and the speculated resorptive functions of secretory stage ameloblasts. We will also study the role of the vasculature in resorption and the possible secretory function of ameloblasts and papillary cells in the maturation stage. We will use appropriate techniques, within our expertise, to identify cells of the enamel organ functioning in secretion and those functioning in resorption. Ultrastructural cytochemistry and short term autoradiography will be used to localize secretory cells, whereas longer term pulse chase methods will localize sites of resorption. Horseradish peroxidase and myoglobin tracer studies, in conjunction with scanning microscopy of lateral cell membranes, will also indicate sites of resorption. Both secretion and resorption sites will be further identified using colchicine, tetracycline, and fluoride to alter normal cell form and function. We will examine vascular casts of the maturation stage to determine if the vascular pattern is compatible with a counter-current mechanism for enamel mineralization and matrix protein removal.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE004230-12
Application #
3218998
Study Section
Oral Biology and Medicine Study Section (OBM)
Project Start
1978-05-01
Project End
1990-08-31
Budget Start
1987-09-01
Budget End
1990-08-31
Support Year
12
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Forsyth Institute
Department
Type
DUNS #
City
Cambridge
State
MA
Country
United States
Zip Code
02142
Skobe, Z; Heeley, J D; Dobeck, J M et al. (1993) Comparison of rates of enamel synthesis in impeded and unimpeded rat incisors. J Dent Res 72:46-50
Skobe, Z; Prostak, K S; Stern, D N (1989) Scanning electron microscopy of monkey secretory- and transitional-stage enamel organ cells. J Dent Res 68:1173-81
Skobe, Z; Prostak, K S; Stern, D N (1988) A scanning electron microscope study of monkey maturation-stage ameloblasts. J Dent Res 67:1396-401
Skobe, Z; Prostak, K S; Trombly, P L (1985) Scanning electron microscope study of cat and dog enamel structure. J Morphol 184:195-203
Skobe, Z; LaFrazia, F; Prostak, K (1985) Correlation of apical and lateral membrane modulations of maturation ameloblasts. J Dent Res 64:1055-61