Zeta potential of oral bacteria (Streptococci).

This study was carried out to examine whether oral bacteria can be treated electrochemically in the same manner as colloid particles. The zeta potentials for 13 Streptococcus strains incubated in trypticase soy broth (TSBY) and heart infusion broth (HIB) were determined in 1/30 M phosphate buffer solution of pH 7.0 by standard microelectrophoresis. The zeta potentials for the Streptococci showed a wide range of values from -28.7 mV to -2.1 mV in TSBY and from -28.5 mV +2.0 mV in HIB. The zeta potential was useful in determining the potential structure of the bacterial cell as living colloid, especially Streptococcus.

Increased remineralization of subsurface enamel lesions with molybdenum treatment.

The present study was conducted to determine the effect of high molybdenum (Mo) concentration on fluoride (F) uptake and remineralization of subsurface lesions utilizing acid cyclic methods in vitro. Bovine enamel with artificial subsurface lesions were treated with test solutions containing 1,000 ppm F (NaF) with and without 1,000 ppm Mo at pH 7.0. F uptake was analyzed using a microdrilling technique and remineralization was evaluated by polarized light microscopy. The results indicate that addition of 1,000 ppm Mo in a 1,000 ppm F solution modestly increases F uptake and promotes remineralization of subsurface lesions compared with 1,000 ppm F alone. These findings suggest that a high level of Mo may enhance the remineralizing activity of F in subsurface bovine enamel lesions in vitro.