الملخص

Different colonial variants of Mutans Streptococci are observed on sucrose containing media such as Mitis Salivarius Agar (MSA). Variation in colony morphology seems to be related to synthesizing cell surface materials, namely; the glucan capsule. Saliva samples from 100 subjects of both sexes aged from 7-52 years old were enrolled. Mutans Streptococci (MS) with various colony morphology and various degrees of adherence were demonstrated in the present study. The incidence of rough colony morphology was shown to be 38% of the local isolates, in addition to that 56% of the saliva samples harbored one strain of Mutans Streptococci, 40% of them had more than one and 4% were negative. The mean DMFT/dmft (Decayed teeth + Missed teeth + Filled teeth) value was 4, 5 respectively. The mean decayed teeth for samples with one strain was 2.8 while samples with two or more strains had an average of decayed teeth 3.6. which indicates that subjects harboring more than one strain have a higher incidence of dental caries than those with one strain. Eight Streptococcus mutans isolates (Mannitol and 2,3,5-Triphenyltetrazolium Chloride positive.) showed various degrees of adherence which is known to be an important virulence factor of this microorganism.