Study on the role of enamel proteins on enamel maturation.

Seeded crystal growth of enamel and synthetic apatites in the presence of enamel proteins has shown that higher molecular amelogenin and enamelin proteins play important roles in regulating enamel apatite growth.In the presence of enamelin，decrease in amounts of the highest molecular weight amelogenin used results in acceleration of crystal growth of enamel apatite.This in vitro finding confirms well-established in vivo correlation between the protein loss from the calcifing front and increase in rate of enamel calcification.Reactions carried out in a cylindrical polyacrylate fistula with each side partitioned by 1000m.w.-retention cellulose dialysis membrane through which only calcium and phosphate ion species were suppsed to diffuse in and out clearly suggested that the degree of calcifing solution supersaturation is important in estimating inhibitory activity of enamel proteins.In this system where the degree of supersaturation was maintained approximately constant through reaction by the use of less seed，enamel apatite was shown to grow almost twice the original seed in length after one week at 37°C and pH7.40。The presence of enamel proteins inside the fistula retarded the rate of crystal growth.The growth process，however，was essentially the same as in the absence of enamel proteins.CNBr-cleaved amelogenins tested in the system mentioned above showed less inhibitory activity than the parental amelogenin。

Seeded crystal growth of enamel and synthetic apatites in the presence of enamel proteins has shown that higher molecular amelogenin and enamelin proteins play important roles in regulating enamel apatite growth. In the presence of enamelin, decrease in amounts of the highest molecular weight amelogenin used results in acceleration of crystal growth of enamel apatite. This in vitro finding confirms well-established in vivo correlation between the protein loss from the calcifing front and increase in rate of enamel calcification. Reactions carried out in a cylindrical polyacrylate fistula with each side partitioned by 1000m.w.-retention cellulose dialysis membrane through which only calcium and phosphate ion species were suppsed to diffuse in and out clearly suggested that the degree of calcifing solution supersaturation is important in estimating inhibitory activity of enamel proteins. In this system where the degree of supersaturation was maintained approximately constant through reaction by the use of less seed, enamel apatite was shown to grow almost twice the original seed in length after one week at 37゜C and pH 7.40. The presence of enamel proteins inside the fistula retarded the rate of crystal growth. The growth process, however, was essentially the same as in the absence of enamel proteins.CNBr-cleaved amelogenins tested in the system mentioned above showed less inhibitory activity than the parental amelogenin.