Studies On The Sterilization Effect And Wastage Of Dental Handpieces

Objective To study the influence of cleaning, disinfection, and sterilization procedures on bacteria and hepatitis B surface antigen(HBsAg) sterilization on the surface and internal cavities of dental handpieces, and the effect on the wastage of dental handpieces, and to explore the role of handpieces users' standings in the influence by the procedures above. And to explore the distribution of wastage on time and departments, and the effect of standings of handpiece users, different sterilizing time(4min vs 8min) on the wastage of dental handpieces.Methods Using Excel 2003, with factors of users' standings and departments were stratified random compatibility,60 handpieces were randomly selected from 100 new handpieces, and randomly assigned to 3 groups of A, B and C, and. handpieces with its' users' working age? 20 years were assigned to Group A, while handpieces with its' users'working age< 20 years were assigned to Group B and C. The sterilization time was 8min,8min and 4min for handpieces after using in Group A, B and C.Using Excel 2003,10 working days stratified random from Jun. to Aug. as monitoring days. After and before handpieces cleaning and after disinfection and post-sterilization, samples from the outer surface and internal cavities of dental handpieces were tested for bacteria and HBsAg. Handpieces wastage during the 1st, the 2nd, and the 3rd month of handpieces use were investigated. And results were analyzed and compared.Results (1) Bacteria was detected both on the outer surface and internal cavities of dental handpieces, and cannot be cleared by either cleaning or disinfection process, and differences were statistically significant (respectively x2= 72.717, P= 0.000, ?2= 4.928, P=0.026). Bacteria were completely removed on the outer surface or the inner cavity of handpiece by sterilization.(2) HBsAg detection rate reached 11.8% from the outer surface and internal cavities of dental handpieces, and cannot be cleared by either cleaning or disinfection process, and differences were statistically significant (respectively ?2==72.717?P=0.000, ?2= 4.928?P=0.026). HBsAg was completely removed on the outer surface or the inner cavity of handpiece by sterilization.(3)There was no significant difference between Group A and B in each processing for clearing bacteria or HBsAg from either the outer surface or internal cavities of dental handpieces (P> 0.050).(4) During three months, a total of 6 handpieces failured, with the handpiece wastage rate reached to 10.0%, and handpieces were totally repaired 10 times. Handpieces were totally repaired 2 times wherein the 2nd month, handpiece while was replaced parts once during the 3 rd month. Compared with the wastage rate in the 1st month, it was statistically significant higher in the 3rd month (?2=6.316, P=0.012); respectively compared to the wastage rate in the 1st and the 2nd month, the wastage frequency rate was both statistically significant higher (?2=7.129, P=0.003; ?2=4.832, P=0.035).(5) During three months, handpiece wastage respectively occurred in sections of the prosthodontic, the endodontic, the oral and maxillofacial surgery and the general. Compared with handpiece wastage frequency rate of the General department, it was statistically significant higher in the prosthodontic section (c2= 4.421, P= 0.035).(6) During three months,, compared with handpiece wastage frequency rate of handpieces in Group A, it was statistically significant higher in Group B(?2=5.458, P =0.019).(7) During three months,, compared with handpiece wastage frequency rate of handpieces of those with standings more than 25 years, that from those with standings less than 5 years was statistically significant higher (?2=6.579, P=0.010).Conclusion Current hospital process for handpiece can effectively play the role of sterilization, and there is no difference in the effect of different standing workers on clearing pathogenic microorganisms in any processes. Focus on strengthening the management of some department such as department of prosthodontic, of low seniority, especially those less than 5 years of work experience, is expected to reduce the handpiece wastage.