Comparative evaluation of the microbial load and dimensional accuracy of dental impressions disinfected with immersion under 2% glutaraldehyde and 0.5% sodium hypochlorite: An ex vivo study

• Author Details:   
• Aishwarya Ramasubramanian
• Mridula Joshi
• Minakshi Bhattacharjee
• Ashwini Panchmahalkar
• Swapnali Mhatre
• Mahesh Ghadage
• Nilesh Joshi
• Sanpreet Singh Sachdev ^*

---

View PDF

Background: Dental impressions are potential vectors for cross-infection due to contamination with saliva and blood. Effective disinfection is critical to prevent transmission of pathogens without compromising the dimensional accuracy of the impressions. This study aimed to evaluate and compare the antimicrobial efficacy of 2% glutaraldehyde and 0.5% sodium hypochlorite on irreversible hydrocolloid (alginate) and addition silicone impression materials and to assess their impact on dimensional stability.

Materials and Methods: An ex vivo study was conducted using impressions obtained from systemically healthy patients. A total of 180 impressions (90 alginate and 90 addition silicone) were randomly assigned to three subgroups (15 samples each): Group A – no disinfection (control), Group B – immersion in 2% glutaraldehyde, and Group C – immersion in 0.5% sodium hypochlorite, each for 10 minutes. Dimensional stability was assessed by measuring inter-point distances on resultant stone casts using digital vernier calipers. Microbial analysis was performed by culturing disinfected impressions on nutrient, blood, and MacConkey agars to evaluate colony-forming units (CFU/cm²) and identify microbial strains.

Results: No statistically significant differences in dimensional measurements were observed across disinfected and control groups (p > 0.05), indicating preservation of dimensional stability. Both disinfectants significantly reduced microbial counts compared to controls (p < 0.001), with sodium hypochlorite showing slightly greater antimicrobial efficacy. Staphylococcus aureus was the most commonly isolated organism. Addition silicone impressions exhibited lower microbial loads than alginate.

Conclusion: Immersion in 2% glutaraldehyde or 0.5% sodium hypochlorite for 10 minutes effectively disinfects alginate and addition silicone impressions without compromising dimensional accuracy. These findings support the inclusion of time-controlled immersion disinfection protocols in clinical and laboratory practice to prevent cross-infection.