Comparative Evaluation of the Antimicrobial Efficacy of Three Different Chemical Disinfectants and their Effect on the Dimensional Stability of Polyvinyl Siloxane (PVS) Impressions

Field: Dentistry (Health Sciences)

The present study was conducted to comparatively evaluate the antimicrobial efficacy of three different chemical disinfectants and their effect on the dimensional stability of polyvinyl siloxane (PVS) impressions.
The antimicrobial efficacy was determined on patient-derived PVS impressions and the dimensional stability was studied on dental model-derived PVS impressions.
To comparatively evaluate the antimicrobial efficacy, a total of 40 patient-derived PVS impressions (10 impressions X 4 Groups) were obtained and divided into four test Groups (Groups I, II, III & IV). Group I Untreated samples were treated as control. Group II samples were immersed in 2.4% glutaraldehyde, Group III samples in 1% Sodium hypochlorite and Group IV samples in freshly prepared Electrolyzed Oxidizing Water (EOW) individually for 10 minutes.
The above test group samples were subjected to microbial culture and the results were quantitatively evaluated for log10 count reduction values and kill rate %, and qualitatively for type and isolation frequencies of microorganisms detected.
To comparatively evaluate the dimensional stability, a total of 30 dental model-derived impressions (10 impressions X 3 Groups) were obtained and divided into three test Groups (Groups V, VI and VII). Group V specimens were immersed in 2.4 % glutaraldehyde for 10 minutes; Group VI specimens were immersed in 1 % sodium hypochlorite for 10 minutes. Group VII specimens were immersed in freshly prepared EOW for 10 minutes.
All the 30 impressions (Groups V, VI, and VII) were subjected to pre and post immersion CT scanning. All these images were reconstructed into 3D images using Mimics software and linear distances between predetermined reference points on the 3D images were measured. The predetermined points chosen were cusp tips of the right and left canine and mesiobuccal cusp tips of right and left first molar. The inter-canine, inter-molar distances and the distances between the respective right and left canines to the respective right and left molars were measured.
The results obtained from both parts of the study were statistically analyzed using one way analysis of variance (ANOVA) and student t-tests. Multiple comparisons were done by Tukey-HSD tests. All the three chemical disinfectants employed in the study showed an acceptable antimicrobial efficacy with log10 count reduction values around or greater than 4, the gold standard for a dental disinfectant and a kill rate % greater than 99%, with no statistically significant dimensional changes.
Among the three disinfectants studied, freshly prepared Electrolyzed Oxidizing Water (EOW) showed highest and statistically significant antimicrobial efficacy as compared to 1 % Sodium hypochlorite and 2.4 % glutaraldehyde and all three disinfectants exhibited statistically similar dimensional stability. The choice of disinfectant agents should be based on acceptable guidelines and operator preference. Electrolyzed oxidizing water is a promising option as a disinfectant for PVS impressions which needs to be investigated for further conclusive recommendations.