Comparative Evaluation of the Effectiveness of Conventional vs Disposable Dental Unit Waterline in Limiting the Contamination of Microorganisms in the Waterline System

Abstract

Context: Cross infection from contaminated dental instruments is a matter of great concern. On sudden stoppage of an air-rotor, the airflow is cut off creating negative pressure in the unit leading to suck-back of saliva from the patient’s mouth. Aims: To detect the presence of microorganisms in the waterline of air rotor units with time. The effect of using disposable waterline on the microbial load was also investigated. Methods and Material: The study was conducted on randomly selected patients having age range of 20 to 30 years, with indication for single or multiple units fixed partial denture fabrication in the Department of Prosthetic Dentistry. In Group A, the existing waterline system after treatment on each patient was examined for determining the influence of time over the degree of microbial contamination. In Group B, the air-rotor handpiece-coupling joint was attached with sterilised disposable plastic tubelines instead of existing tubeline. Water samples collected from air rotor units and watercan of both Group A and B before and during use for 15,30 & 45 minutes were subjected to microbiological study. Statistical analysis used: Chi-square test was used to assess the effect of time on the microbial load from the data obtained. Results: After 45 minutes of use, 50% of the samples in group A were positively related to microbial contamination and the result obtained from Group B were negative. Conclusions: Air-rotor with existing tube line after 45 minutes of use is significantly responsible for the contamination. Air-rotor with disposable tube line on the contrary could be used without risk of contamination on the next patient even after 45 minutes. Keywords: Air rotor handpiece, Source of bacterial infection, Biofilm, Disinfection.