Abstract:Twenty five Streptococcus isolates -were obtained from plaque samples and identified using "biocnemical identification system. The growth rate of these isolates was measured and accordingly eight isolates were chosen which gave a higher growth rate and represented the major Streptococcus species involved in dental disease development. Physiological processes were implicated during this study for the improvement of a type of control upon the growth and metabolism of Streptococcus isolates. These processes involve inhib of growth * acid production from the isolates such inhibition was achieved through the use of chemical compounds represented "by sodium fluoride, chlorhexedine, zinc sulphate, SDS, hexetidine and iodine in addition to the use of sugar substitutes, sorbitol to reduce the incidence of carbohydrate utilization. Depending upon the final pH-value and growth rate of the isolates, chlorhexidine was found to be the most effective inhibitory agent followed by sodium fluoride and SDS. However, sodium fluoride was found to exert an inhibitory action closely resemble that produced "by chlorhexidine when the initial pH value was adjusted to C5-6) although, an obvious resistance appeared with one of the isolates to sodium fluoride and this would provide an evidence that some of the Streptococcus species reflect resistance to sodium fluoride similar to that obtained with antibiotics. Sorbitol was found to stimulate growth of the isolates with the inhibition of pH reduction. However , base generating compounds i.e. urea was found to show a good inhibitory effect upon the growth of the bacterial isolates, since it causes a raise in the surrounding pH to that associated with base generation . According to this a balance in the composition of the oral streptococci that were related to dental plaque formation and disease development through the implication of such physiological strategies in a controlled system could be effective.