Inhibition of hydroxyapatite crystal growth by lipoteichoic acid

Lipoteichoic acids were purified from freshly isolated strains of Streptococcus sanguis and Lactobacillus casei, and from a laboratory strain of Strep. rattus BHT. Their effects on the seeded growth of hydroxyapatite in 1 mM CaCl2, 7.5 mM KH2PO4, 50 mM HEPES (pH 7.2) were determined. At lipoteichoic acid concentrations of 25 microM organic phosphate (Po) and higher, the growth of hydroxyapatite appeared to be inhibited, at 100 microM Po inhibition was complete for several hours. In contrast, low concentrations of lipoteichoic acids (5-10 microM Po) may have a stimulatory effect on the seeded growth of hydroxyapatite. It was concluded that lipoteichoic acid may be one of the bacterial products that inhibit enamel lesion repair in vivo.