title: Influence of amalgam on the growth of mutans streptococcus: an in vivo study.
abstract: OBJECTIVE
  To study the antibacterial activity of dental amalgam against mutans streptococcus.
  
  
  METHODS
  Study volunteers included 14 patients, 21 to 35 years old, with aged amalgam fillings, with no antibiotic use during the previous 3 months, and 16 patients, 22 to 24 years of age, without aged amalgams, but with unfilled caries. Plaque samples were collected once from the subjects with aged amalgams. Subjects with fresh amalgams had plaque samples collected at 1 day, 1 week, 2 weeks, 4 weeks, and 8 weeks after amalgam restoration. As controls, plaque samples were collected from unrestored occlusal enamel surfaces on the same side, or on the opposite side of the same occlusion. Frequency of mutans streptococci from aged amalgams and fresh amalgams and the colony-forming units (CFU) were tested.
  
  
  RESULTS
  The difference of CFU of mutans streptococci in the plaque samples between the amalgam restorations, the aged amalgams, and the controls was not significant within 8 weeks after amalgam filling. The difference of CFU of mutans streptococci in plaque samples from the amalgam restorations between all the timepoints was significant except between the fourth week and eighth week. For the control group, however, the difference in values between the first day and the timepoints afterward were significant, except between the first day and the first week. The difference between the first week and later timepoints was significant, but not between the second week and later, or between the fourth week and later. At the eighth week, the difference between the aged-amalgam and controls was not significant.
  
  
  CONCLUSIONS
  Amalgam had some inhibitory effect on the in vivo growth of mutans streptococci.
authors: Department of Oral Medicine, School of Stomatology, Shanghai Second Medical University (SSMU), No. 639 Zhizaoju Road, Shanghai, 200011, P. R. China.
authors: J
authors: J
authors: Wang
authors: Z
authors: Z
authors: Liu
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003723:Dental Amalgam / Q000494:pharmacology*; D003731:Dental Caries / Q000382:microbiology; D003743:Dental Enamel / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology; D003793:Dental Restoration, Permanent; D005500:Follow-Up Studies; D006801:Humans; D013223:Statistics as Topic; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D003723:Dental Amalgam