The effect of toothbrush covers on microbial contamination

Abstract

Introduction: The toothbrush is considered the most effective instrument for the removal of biofilm, a major etiological factor in the development of caries and periodontal disease [1]. Toothbrushes are often stored in the bathroom, next to the sink and the toilet, and may be exposed to various types of bacteria, harboring potentially harmful microorganisms [2]. It is therefore extremely important that toothbrushes are stored in a suitable place, and undergo frequent disinfection, in order to prevent the growth of microorganisms. The bristles can, therefore, be contaminated thanks to the oral cavity itself or the surrounding environment. [3] The aim of this study was to evaluate the microbial contamination of covered (CT) versus uncovered toothbrushes (UT).

Materials and methods: After study approval by the Ethics Committee of the Cooperativa de Ensino Superior Egas Moniz (Protocol 587), students of Dentistry at Instituto Universitário Egas Moniz were invited to participate in this study. Inclusion criteria: being capable of performing daily oral hygiene and signing the informed consent. Exclusion criteria: not following the protocol or being under the effect of antibiotics or antifungals. Following the informed consent, each participant was given a toothbrush and instructions regarding its use of oral hygiene, for 3 weeks. The participants were divided by simple random sampling, in two groups of 15 participants each, according to the toothbrush being covered or uncovered. After the 3 weeks period, the toothbrushes were collected and processed in order to evaluate the microbial content. They were submerged in a sterile saline solution which was used to inoculate different culture medium.

Results: The sample was composed of 30 students, 77% of them women, with an average age of 21.9 (±1.7) years. All the CT (100%) showed viable aerobic microorganisms isolates (2.3 × 10⁶ ± 2.2 × 10⁶ cfu/toothbrush), but on UT only 93.3% presented microorganisms growth (1.2 × 10⁶ ± 1.9 × 10⁶). No beta hemolytic microorganisms were found in both CT and UT, and alfa hemolytic were found only in CT (20%). Staphylococcus mannitol positive were found on 66.6% of CT and 53.3% of UT. Oral Streptococci were isolated in 37.3% of CT, and in 30.6% of UT. Enterobacteriaceae were isolated in both CT and UT in an identical percentage (33.3%), being E. coli isolated in a higher percentage in CT (20% vs. 6.6% on UT). Candida albicans was only isolated on UT (on 6.6% of samples).

Discussion and conclusions: Our results show that toothbrushes were heavily contaminated with different microorganisms, and suggest that contamination does not depend on toothbrush covering.

Acknowledgements

The authors would like to acknowledge all the participants that took part in this study and Colgate-Palmolive for providing the toothbrushes.