Microbiological assessment of the effectiveness of chlorhexidine mouthrinse before taking impressions of the oral cavity

purpose: the aim of this study is to assess the reduction of microbial load that adhered to irreversible hydrocolloid impressions obtained after rinsing with 0.12% and 0.2% chlorhexidine solutions. methods: the study consisted of 24 participants (48 dental arch impressions) equally divided into two groups: group 1 (0.12% chlorhexidine) and group 2 (0.2% chlorhexidine). the impressions were taken using hydrogun？ irreversible hydrocolloid before (control) and after (experimental) a single 10 ml mouthrinse of chlorhexidine for 1 minute. each impression was placed in a sterile beaker containing 250 ml of saline. the microbiological analysis of the storage solution was carried out using bhi agar culture medium. the plates were incubated for 24 hours, followed by a cfu (colony forming units) count. the data were analyzed using the wilcoxon's t test. results: there was a reduction in the degree of contamination of the impressions after rinsing with the antimicrobial mouth rinses at both concentrations when compared with the control group. there was a statistically significant difference when the effectiveness of the two concentrations used was compared. conclusion: therefore, using a chlorhexidine rinse prior to obtaining irreversible hydrocolloid impressions reduces contamination and is more efficient at the 0.2% concentration.