Effect of microwave and sodium hypochlorite disinfection of alginate impressions on dimensional accuracy of such impressions

Effects of Disinfection on Alginate Impression Accuracy

Abstract

Objective:  This study investigated the impact of disinfection methods, specifically sodium hypochlorite and microwave irradiation, on the dimensional accuracy of alginate impressions.

Methods: This was a randomized comparative clinical study. A purposive sampling technique of consecutive individuals was employed for the study. The maxillary impression of employed participants was made and randomly assigned to either of two groups (microwave irradiation vs sodium hypochlorite disinfection) by simple random technique. Two impressions were made for each participant. The first impression was poured with dental stone to make a stone cast without disinfection, the second impression made, was disinfected either using 0.5% sodium hypochlorite disinfectant or microwave irradiation for 2 minutes, before a stone cast was made from this impression. The dimensional accuracy of each cast was assessed by measuring the bucco-palatal width of the two maxillary first molars using a handheld digital caliper (with an accuracy of 0.01mm) and getting the average of the two measurements. 

Result: A total of 120 upper impressions were made using alginate impression material for 60 participants. The buccolingual dimension of the first molars ranged from 4.32 to 6.10mm before and after sterilization. The mean buccolingual dimension before sterilization was 5.30±0.39 and the mean buccolingual dimension after disinfection was 5.30±0.42, which was not statistically significant (p=0.78). Disinfection with sodium hypochlorite (p=0.94) and microwave irradiation (p=0.74) on the dimensional accuracy of impressions was not statistically significant

Conclusion: There were no significant dimensional inaccuracies in casts obtained from alginate impressions disinfected with sodium hypochlorite or microwave irradiation compared to those obtained from alginate impressions without disinfection