Should Surgical Burs Be Used as Single-Use Devices to Avoid Cross Infection? A Case-Control Study

The purpose of this study was to evaluate and compare the rate of bacterial contamination of reused and new unused burs after different sterilization sessions.

The test group consisted of 40 used fissure burs, and the control group of 40 unused new fissure burs (total n = 80). The burs from both groups were precleaned according to standard protocols and then subjected to two sterilization sessions (high- and low-steam pressure autoclaving). After each sterilization session, the burs were transferred into incubation tubes which contained thioglycollate culture medium and were monitored daily for a period of 48 h to detect any bacterial growth. Data were collected and statistical analysis was done using Fisher's exact test.

Of the 40 burs of the test group, 2 burs (5%) showed positive bacterial growth, whereas no bur from the control group showed any sign of bacterial growth after high-pressure autoclaving. The colony structure and Gram staining were compatible with the growth of Staphylococcus epidermis. After a second sterilization session at low-pressure steam autoclaving, no bacterial growth was observed for the test group, but 1 bur (2.5%) from the control group showed bacterial growth and Gram-positive staining matched well with the growth of Brevibacterium species.

The new and unused burs were 100% sterile after high-pressure steam autoclaving, whereas 5% of the reused burs appeared positive with bacterial contamination. After low-pressure steam autoclaving, reused burs were 100% sterile, but 1 new bur demonstrated bacterial contamination.