Tooth decay  are considered the most common  in the world. In spite of the caries of the teeth since childhood, its spread increases with time and this increase is associated significantly with the change of dietary mode of modern humans .The study aims to isolation and identification of important bacteria related to tooth decay, determining the sensitivity of bacteria of certain types of antimicrobial agents and studying the effect of heavy metals on bacterial isolates. A total (50) swabs were collected from mouths of patients from both sexes and their ages range from 1-60 years which are referred to consult the dental clinics and specialized centers, in order to isolate and identify the causative agents that associated with oral diseases . The age group of infection rates showed groups  (20-40) and (1-20) were the most infected compared to elder group (40-60) as was the incidence of 44and 32% respectively The antibiotic sensitivity test  against the isolates showed the chloramphenicol up to 83.05% was the higher effect sensitivity of Gentamicin  and  Rifampicin up to 81.35% .While streptomycin 16.94% and penicillin G 64.40% . Also, these differences were found have lower effect for isolates against (7) heavy metals, where it showed  resistance to Silver nitrate, Iron chloride, Zinc chloride, lead acetate to100%, while appeared  sensitivity to mercury, cadmium  and  copper sulfate by 100,86.44and 1.69% respectively.