A comparative study between microwave irradiation and sodium hypochlorite chemical disinfection: a prosthodontic view

Abstract

Background: Prosthodontic procedures involving dental impressions, stone casts, record bases and prostheses may cause transmission of microorganisms between the patient, the dentist, auxiliary staff and laboratory personnel. In recent times, microwave radiation has gained wider acceptance in the field of applied science and has been used to reduce concentrations of bacteria and fungi, to dry dental casts,and to sterilize preparation media.

Objective: This in-vitro study was conducted to compare microwave irradiation and 0.07% sodium hypochlorite chemical disinfection. The study also evaluated the effect of microwave irradiation and 0.07% sodium hypochlorite chemical disinfection on the dimensional stability of Kalstone casts.

Materials and methods: Forty impressions were made and divided into two groups of 20 each. Each group was contaminated with Staphylococcus aureus and Pseudomonas aeruginosa respectively. Each impression was divided into three parts and marked A, B, C. Impressions were then poured in kalastone. Part A of 20 kalastone casts were microwave disinfected, and Part B were chemically disinfected (0.07% NaOCl) while Part C were not disinfected and used as control.

Results: On comparing the significant difference was seen in the microbial load between microwave and chemical disinfection (Z=56.480; p<0.001).

Conclusion: On the basis of observations made for the antimicrobial assessment the microwave irradiated Kala stone casts proved to be a better disinfection method when compared with 0.07% sodium hypochlorite chemically disinfected incorporated cast. No significant difference was seen in the dimensional stability of Kala stone discs.

Keywords: Chemical disinfection; Kala stone; Sterilization.

[Table/Fig-1]:

Colonies of Staphylococcus aureus of control group

[Table/Fig-2]:

Colonies of Staphylococcus aureus of chemical disinfection group

[Table/Fig-3]:

Colonies of Staphylococcus aureus of microwave irradiation group

[Table/Fig-4]:

Colonies of Pseudomonas aeruginosa of control group

[Table/Fig-5]:

Colonies of Pseudomonas aeruginosa of chemical disinfection group

[Table/Fig-6]:

Colonies of Pseudomonas aeruginosa of microwave irradiation group

[Table/Fig-7]:

Method to evaluate dimensional stability