Objectives: This study investigated the bacterial and fungal contamination of used dental burs. A novel assay system for comparison of efficacy of pre-sterilisation cleaning techniques for dental burs was used to evaluate manual scrubbing, enzymic agents and washer-disinfectors. Methods: Thirty dental burs contaminated during cavity preparation were analysed for micro-biological total viable counts and species of bacteria and fungi present. To simulate clinically contaminated burs, a culture of Streptococcus sanguis NCTC 7863 was used to inoculate unused dental burs, alone and combined with blood, saliva or a mixture of blood and saliva. Contaminated burs were subjected to six pre-sterilisation cleaning techniques and the log reduction in contamination achieved by each method was assessed. Results: The microbial count from used dental burs ranged from 0 to 6.92×10 4 CFU ml -1. Many potentially pathogenic species were identified. The decontamination assay demonstrated that autoclaving alone was not sufficient to sterilise dental burs. Manual scrubbing in air was less efficacious than manual scrubbing under water (p
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机译：目的：这项研究调查了用过的牙钻的细菌和真菌污染。一种用于比较牙垢消毒前清洁技术功效的新颖测定系统，用于评估人工擦洗，酶制剂和清洗消毒器。方法：分析了在制腔过程中被污染的30个牙钻的微生物总生存量以及所存在的细菌和真菌的种类。为了模拟临床上受污染的牙钻，将血链球菌NCTC 7863培养物单独接种并与血液，唾液或血液和唾液的混合物一起接种未使用的牙钻。受污染的钻针经过六种预消毒清洁技术，并评估了每种方法所实现的污染对数减少。结果：使用过的牙钻的微生物计数范围为0到6.92×10 4 CFU ml -1。确定了许多潜在的致病物种。净化试验表明，仅进行高压灭菌不足以对牙钻进行灭菌。空气中的手动洗涤比水下的手动洗涤效率低（p
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