Objective: The objective was to compare the rate of mineral loss of hydroxyapatite disc treated
with five different sequences to that of hydroxyapatite disc treated with StN21 using SMR.
Materials and Methods: The aim of this study was to identify the functional domain of statherin
required for its cariostatic function by measuring the efficacy of STATHERIN-like peptides with
five different amino-acid sequences (StN21 1A, StN21 2A, StN21 3A, StN21 4A, and StN21 5A)
at the N-terminal respective, in vitro using scanning microradiography.
Hydroxyapatite discs of known (20%) porosity, used as an ideal system for enamel. Discs were
covered with acid-resistant varnish on all surfaces except for the surface to be tested, and then
placed in SMR cells and fixed on the SMR horizontal stage. Discs were demineralized by 0.1 M
acetic acid buffered of pH 4.0 for about 72 hours.
Results: It was found that the effect exerted by the N–terminal of the StN21 peptide on the rate
of Hap mineral dissolution was (44%) StN21 1A (53%), StN21 2A(31%), StN21 3A(49%), StN21
4A(46%) StN21 5A(48%),and finally phosphate buffer (1%).
Conclusion: Not only do the five amino acids in the N-terminal, i.e. aspartate, phosphated serine,
and glutamic acid are involved in cariostatic activity, but also, there are other amino acids to play
a vital role in inhibition of mineral loss. Moreover aspartate and phosphate serine are found to
be least involved in inhibiting mineral loss when compared to another sequence