A Comparative Study of the Effect of Different Disinfectant Solutions on the Compressive Strength of Type III Gypsum

To investigate and compare the effect on compressive strength after incorporation of disinfecting solutions (sodium hypochlorite and povidone iodine) to commonly available type III dental stone.

A total of 90 dental stone samples of 20 × 40 mm were made. The standardized samples were fabricated according to the ADA specification no. 25 using custommade silicon mould and divided into 3 groups. Group A, type III gypsum was incorporated into distilled water; Group B, sodium hypochlorite (3%) was incorporated into distilled water in the ratio of 1:10 concentration according to ADA specification; and Group C, povidone iodine (3%) was incorporated into distilled water. The mix was carefully vibrated into the silicone mould and allowed to set. The specimens were subjected to compressive load after 1 and 24 h from the time of mixing using an Universal Instron testing machine. The result obtained were tabulated and subjected to statistical analysis using twoway analysis of variance tests.

This study showed that incorporating the disinfecting solutions like sodium hypochlorite and povidone iodine decreases the compressive strength of type III dental stone. The effect of decreasing compressive strength on type III gypsum product is seen more in povidone iodine when compared to sodium hypochlorite disinfecting solution.

Incorporation of sodium hypochlorite and povidone iodine disinfecting solutions is not an encouraging method as it reduces the compressive strength of type III gypsum product.