Objective: To compare oral hygiene practices, education and social background, food intake and oral malodor of Algerian adults suffering from dental caries with normal controls, and to determine and compare the bacterial composition of the supragingival plaques from the above-mentioned groups.Methods: Participants completed a questionnaire and were clinically examined for dental caries using decayed, missing and filled teeth index according to the criteria laid down by the World Health Organization. Supragingival plaque samples were collected from 50 caries-free adults(CF) and 50 caries-active adults(CA). Standard procedures of culture and identification of aerobic and anaerobic bacteria were used. Data were analyzed using Chi-square test.Results: A total of 117 bacterial strains were isolated from supragingival plaques in CF group subjects, 76(64.96%) of them belonged to 9 aerobic genera, and 41(35.04%) to 9anaerobic genera(P < 0.05). While in the second group, 199 strains were isolated, 119(59.80%) of the strains belonged to 10 aerobic genera and 80(40.20%) to 10 anaerobic bacteria(P < 0.05). Streptococcus mutans, Enterococcus faecium, Aerococcus viridans,Actinomyces meyeri, Lactobacillus acidophilus and Eubacterium limosum showed a significantly higher prevalence in the CA group(P < 0.05). The findings revealed that CA group had a high sugar intake(80%). A significantly higher frequency of tooth brushing(P < 0.000) and a significantly less self-reported oral malodor(P < 0.000) and tooth pain(P < 0.000) were found in CF group, while there was no association of socioeconomic levels and intake of meal snacks with dental caries.Conclusions: This study confirms the association of some aciduric bacteria with caries formation, and a direct association of sugar intake and cultural level with dental caries.Furthermore, oral hygiene practices minimize the prevalence of tooth decay. Objective: To compare oral hygiene practices, education and social background, food intake and oral malodor of Algerian adults suffering from dental caries with normal controls, and determine and compare the bacterial composition of the supragingival plaques from the above-mentioned groups. Methods: Participants completed a questionnaire and were clinically examined for dental caries using decayed, missing and filled teeth index according to the criteria laid down by the World Health Organization. Supragingival plaque samples were collected from 50 caries-free adults (CF) and 50 caries-active Adults (CA). Standard procedures of culture and identification of aerobic and anaerobic bacteria were used. Data were analyzed using Chi-square test. Results: A total of 117 bacterial strains were isolated from supragingival plaques in CF group subjects, 76 (64.96% ) of them belonged to 9 aerobic genera, and 41 (35.04%) to 9anaerobic genera (P <0.05). While in the second group, 199 were isolat (P <0.05). Streptococcus mutans, Enterococcus faecium, Aerococcus viridans, Actinomyces meyeri, Lactobacillus acidophilus and Eubacterium limosum showed a Significantly higher prevalence in the CA group (P <0.05). The findings revealed that CA group had a high sugar intake (80%). A significantly higher frequency of tooth brushing (P <0.000) and a significantly less self-reported oral malodor (P <0.000) and tooth pain (P <0.000) were found in CF group, while there was no association of socioeconomic levels and intake of meal snacks with dental caries. Conclusions: This study confirms the association of some aciduric bacteria with caries formation , and a direct association of sugar intake and cultural level with dental caries .Furthermore, oral hygiene practices minimize the prevalence of tooth decay.