Effect of Autoclave on Bacterial Growth Isolated from Different Types of Denture Adhesives

Abstract

Background: Different types of denture adhesives like powder or paste have been used to enhance the retention and stability in denture wearers, especially in patients with resorbed ridges , these adhesives should be free from microbial contamination in order to use safely inside patient mouth and avoid infection , the purpose of this study is to investigate the bacterial contamination of different adhesives pastes and powders and the effect of autoclaving in reducing the bacterial growth . Materials and Methods: Six types of commonly available denture adhesives (three powders and three pastes) were tested for bacterial contamination by using culture on suitable media that contained either brain-heart infusion (BHI) ,blood agar, nutrient agar,MSA agar and others were inoculated with 0.5 gm samples of each adhesive. plates were incubated at 37C˚ for 24 hours in pre and post sterilization by using the colony forming unit for estimation the bacterial growth. Results : The results revealed that , In pre sterilization test all adhesive types (powders and pastes ) contained Gram positive and Gram negative bacteria ,the results also revealed that Dentofix (paste type 1) has the lowest bacterial growth in which 40% without bacterial growth , also the results reported that 25% of adhesives were contaminated by Staphylococcus species and 23 % of adhesives were contaminated by Neisseria species .Dentofix paste was highly significant difference regarding the mean of bacterial count at both dilutions 1/10 and 1/100 among other adhesives with the lowest contamination in comparison to other types of denture adhesives in presterilization step.while after using sterilization by autoclave generally sterilization induce high significant difference in each type of denture adhesive after exposure to autoclave for 15 min at 121 °C 15 pound/inch it decreases the number of bacterial growth in all types. The results showed that powders adhesives had high contamination rate than pastes and their killing rate after sterilization was lower than pastes. Fittydent (paste type 3) was highly affected by sterilization than other adhesives in first dilution 1/10 when killing rate was 78.9% . all types of tested adhesives showing that in second dilution 1/100 sterilization more effective at this dilution and sterilization induce 100% killing in Dentofix ( paste type 1) , Bonyplus ( paste type 2) and Fittydent (paste type 3) . Conclusions: The result of this study concluded that the powders denture adhesive have high bacterial contamination rate than the pastes and using of sterilization by autoclave must be done to increase killing rate.