Assessment of contamination on sterilised dental burs after being subjected to various pre-cleaning methods.

OBJECTIVE: To determine the effectiveness of different pre-cleaning methods by determining frequency and site of contamination on the sterilised dental burs using Phloxine B dye. METHODS: The in-vitro experimental study was conducted from June to August 2017 at dental clinics of Aga Khan University Hospital Karachi. Diamond dental burs were selected and divided into two control and four test groups. The two control groups were classified as Negative (new burs) and Positive (used contaminated). The four test groups were classified as Manual (Group-1), Ultrasonic (Group-2), Manual + Enzyme (Group-3) and Manual + Ultrasonic (Group-4). Phloxine B dye was used to determine the contamination. The images of the burs were taken and enlarged at 15X before subjected to visual assessment. Association between contamination and pre-cleaning methods were determined. Data was analysed using SPSS version 22. RESULTS: A total of 210 burs were selected for the study which were divided in 6 groups of 35(16.66%) each. One (2.8%) bur in negative control group and all burs in positive control group showed contamination. In test groups, 27(77.1%), 29(82.8%), 27(77.1%) and 24(68.5%) burs showed contamination in groups 1, 2, 3 and 4, respectively. There was no association between type of pre-cleaning method with the frequency of contamination (p =0.57). The head of bur was the most frequently contaminated site (p < 0.003). CONCLUSIONS: None of the pre-cleaning method was found to be effective. Head of bur was the most frequently contaminated site.