Effectiveness of selected surface disinfectants in the dental clinic – a report from a tertiary training facility in KwaZulu-Natal.

Abstract

Optimal infection control practice forms the cornerstone of quality oral health care delivery in any dental setting. There is very little published evidence on dental infection control practices in South Africa. In addition there is a paucity of evidence that specifically examined the efficacy of commonly used surface disinfectants in oral health clinical settings. The aim of this study was to determine the effectiveness of selected surface disinfectants on specific dental environmental surfaces in an identified public oral health training facility in KwaZulu-Natal. The objectives included the identification and classification of environmental areas that are at risk for cross-contamination in the dental clinic, and comparison of the microbial count at specified times of the day after the use of three surface disinfectants. This was a prevalence (cross-sectional), descriptive research study with a non-experimental design. Data collection included the application of three commonly used surface disinfectants (Chlorine®, Ethanol and Glutaraldehyde) on identified dental environmental surfaces in a public sector dental clinic facility in KwaZulu-Natal. The clinic consists of seventeen dental units that are numbered from one to seventeen. Systematic random sampling technique was used to select selected every second chair for the study (Dental Unit number: number: 1, 3, 5, 7, 9, 11, 13, 15, 17). The dental clinical environment was then divided into four zones: 1): the working area around the dental operator/assistant (chair, head rest, arm rest, foot rest, dental hand pieces, overhead light source, air water syringe tip, spittoon, suction hose, based of dental chair, dental stool, foot control, instrument counter and handle); 2): the area behind chair (wash basin, computer monitor, window, wall, table top, dust bin and taps): 3): the area away from chair (computer processing unit, telephone and floor); and 4): the reception area (patient chairs and reception table top). The swab samples were collected at specific time intervals (7am, 9am, 11am, and at 16.00) using a charcoal swab. Chlorine, Ethanol (70% in water) and Glutaraldehyde (2%) disinfectants were applied separately on the identified nine dental units by using a spray method. Use of the MALDE-TOF spectrometer enabled the mass spectra to be acquired and the bacteria to be identified. Out of the 312 samples taken, 262 (84%) were shown to be bacterial culture positive. More than seven microbial species were identified in which staphylococci, Bacillus species and fungi were present. The most contaminated areas in the dental environment were the area around the chair (86.5 %) and away from chair (92%). The results indicate that Chlorine® was not active against several bacteria because 92% samples had positive growth at the end of the day. Only 56 % of the samples using Ethanol were positive in the morning but the microbial growth increased to 96 % by the end of the day. The use of Glutaraldehyde indicated that 52% of samples were positive at 9 am but that 82% were found to be positive at the end of day. The bacterial survival rate was found to be less with the use of Glutaraldehyde. The study suggests that there was an association between frequency of cleaning, the type of disinfectants used and the microbial count on the specified dental environmental surfaces in the identified oral health facility. The findings therefore indicate that disinfection processes at the identified dental centre are inadequate, sub-optimal and could contribute to the infection chain. There is an urgent need to review the current infection control procedures and protocols, including a review of the type of surface disinfectants used. The frequency of disinfection (damp-dusting and housekeeping) must be reviewed, given the number of patients that are seen on a daily basis. It is also important that simple procedures such as awareness of hand hygiene practices are implemented and prioritized. There should also be dedicated infection control monitoring and evaluation processes.