Indian Journal of Dental Research

: 2009  |  Volume : 20  |  Issue : 4  |  Page : 404--406

Effect of a single-use toothbrush on plaque microflora

Vidya Pai 
 Department of Microbiology, Yenepoya Medical College, Mangalore, Karnataka, India

Correspondence Address:
Vidya Pai
Department of Microbiology, Yenepoya Medical College, Mangalore, Karnataka


Aim: To study and compare the microbial flora of dental plaque after the use of a self-contaminated toothbrush and that of a single-use toothbrush. Materials and Methods: The study group included 40 young volunteers from Yenepoya Dental College, who were free from any systemic or oral disease. In these subjects, plaque samples were collected after 1 month use of a self-contaminated toothbrush. Each subject was given a set of 30 new toothbrushes and a toothpaste tube and instructed to use one toothbrush everyday and discard it after use. The plaque samples were collected on a weekly interval and cultured on Mitis Salivarius agar. The colonies were identified and speciated and their count was recorded. Results: Streptococcus mitis, S. mutans, S. sanguis, S. milleri and Candida were recovered from the samples. A highly significant decrease in their numbers was found after the use of a single-use toothbrush (P value 0.001). Conclusions : As a contaminated toothbrush can reintroduce microorganisms into the oral cavity, it may be a sound practice to change the toothbrush as frequently as possible.

How to cite this article:
Pai V. Effect of a single-use toothbrush on plaque microflora.Indian J Dent Res 2009;20:404-406

How to cite this URL:
Pai V. Effect of a single-use toothbrush on plaque microflora. Indian J Dent Res [serial online] 2009 [cited 2021 Oct 20 ];20:404-406
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Full Text

The most common devise used for oral hygiene maintenance is a toothbrush. This devise is designated for mechanical cleaning of teeth, i.e. essential for removing the dental plaque, which is a contributor to dental caries and periodontal disease. The oral hygiene device maintenance is as important as that of oral hygiene itself. [1] During tooth brushing, the toothbrush gets contaminated with microbes present in the oral cavity. After brushing, rinsing with plain water may not eliminate all the microorganisms. [2] Adding to this, storage, especially in a moist environment, may induce residual organisms to grow and the brush may also get contaminated with new organisms from the storage environment. [2] Thus, contaminated toothbrushes may act as a reservoir to reintroduce the microbes into the oral cavity on subsequent use. [3] Thus, the possibility of a reused toothbrush in the contamination or spread of the disease has become increasingly important in the recent years. This study was conducted to quantify the microbial flora of the dental plaque with the use of a self-contaminated toothbrush and with the use of a "single-use" toothbrush and then to compare the two.

 Materials and Methods

The study was conducted in the Departments of Oral Pathology and Microbiology, Yenepoya Medical and Dental College, Mangalore, over a period of 2 months.

A total of 40 young volunteers from these colleges were selected for the study, comprising 20 males and 20 females in the age group 18-25 years. The subjects were assessed for systemic and oral health. Volunteers without any systemic diseases like diabetes and hormonal disorders and oral diseases like gingivitis and periodontitis were included in the study. The selected subjects had no oral habits, like smoking, alcoholism and tobacco chewing, and were also not administered any antibiotics during the study period.

After obtaining an informed written consent from each volunteer, a thorough oral prophylaxis was performed on each subject. Then, each one was given a new toothbrush and toothpaste and instructed to use the same everyday. No instructions regarding the storage or cleaning of the toothbrush were given so that the volunteers followed their regular practice. At the end of 1 month, the dental plaque sample was collected from each subject. Each volunteer was asked to gargle his or her mouth with saline to remove any food debris. Taking all aseptic measures, the plaque was collected from the buccal groove of the lower first molar tooth using a sterile paper point so that the standardized length of the paper point (colored area) touched the tooth for 5 sec. This specimen was immersed in 1 ml of phosphate-buffered saline (PBS).

These plaque specimens were vortexed for 10 sec and immediately subcultures were performed on Mitis Salivarius (MS) agar and Sabouraud's Dextrose agar (SDA) taking 5 ml of plaque in PBS. The inoculated agar plates were incubated at 37°C aerobically in a CO 2 incubator for 48 h.

The colonies were identified based on colony morphology. The colonies with similar morphology were counted using a colony counter and their numbers were recorded.

During the second month, each volunteer was given a set of 30 new toothbrushes and a toothpaste tube. They were instructed to use one toothbrush everyday and discard it after a single use. They were also instructed to avoid touching the mouth of the toothpaste tube or the bristles of the new toothbrushes with their fingers.

In the second month, plaque sample was collected on a weekly interval and sent for culture. Thus, four samples from each volunteer were obtained in the second month.

According to the colony morphology, the isolates were speciated on MS agar and their numbers were recorded. The results of the first month end samples and the weekly samples of the second month were subjected for statistical analysis using Paired t-test and Turkey's honestly significant difference test (HSD).


Four different species of Streptococci (S. mitis, S. mutans, S. sanguis and S. milleri) were studied as these are the most frequently recovered group of microbes from the dental plaque. According to Taji et al., [3] Candida species can colonize the toothbrush and hence the present study included Candida also.

[Table 1] shows the comparison of four different species of Streptococci and Candida between the first month of self-contaminated brush use and the 4 weeks of single-use toothbrush use. It shows a very highly significant decrease in the number of microorganisms. The analysis showed a P value of 0.001 for S. mitis, S. mutans and Candida, 0.006 for S. milleri and 0.032 for S. sanguis.

[Figure 1] shows the comparison of the levels of Streptococci and Candida after use of "single-use" toothbrush and there is a decline in the mean value of these organisms with changing the toothbrush everyday.


The plaque is the etiologic agent in many oral diseases and the removal of plaque is the most important step toward a hygienic oral cavity. Removal of plaque is performed with various oral hygiene devices, of which toothbrush is the commonly used one. After brushing and also during storage, the toothbrush may get contaminated with some microbes.

Various studies have shown that bacteria can colonize on the bristle surface of a used toothbrush. Nelson et al. [4] have shown that Candida, Staphylococci, Corynebacteria, Pseudomonas and Coliforms can colonize and Brook et al. [5] have shown that group A beta hemolytic Streptococci can colonize on a toothbrush. Studies also show that viruses and fungi can contaminate used toothbrushes. [6] The toothbrushes are commonly stored in the bathrooms and may thus get contaminated by aerosols from the toilet as well as by contaminated fingers. Many researchers believe that the level of contamination is closely related to the dryness achieved during storage. [3]

Whatever be the source of contamination of the toothbrush, the fact of importance is that this contaminated toothbrush can be a source of reinfection and can thus alter the oral microflora. In the present study, four different species of Streptococci - S. mutans, S. mitis, S. sanguis and S. milleri on MS agar and also Candida on SDA were isolated from dental plaque.

Studies performed in the past were concerned in knowing the contamination of toothbrushes, disinfecting them and in knowing the effectiveness of the disinfecting solution. The present study was carried out to know the difference in the quantity of microorganisms in the plaque after using a self-contaminated toothbrush and single-use toothbrush.

Different studies show different time periods for the contamination of the toothbrush with S. mutans, which varies from 1 to 30 days. Although the favorable habitat of S. mutans is the tooth surface, it does not uniformly colonize on all tooth surfaces but, instead, localizes on certain surfaces. Christerson et al. [6] have shown that S. mutans can be transmitted from colonized to non colonized areas through the toothbrush. S. mitis showed a significant reduction in the mean value in the present study. The reduction in S. sanguis was not as significant as that seen in S. mitis and S. mutans.

It has been reported by Parker et al. [7] that S. mutans and S. sanguis exhibit an antagonistic relationship. This might be the reason for not observing a decrease in the number of S. sanguis in comparison with S. mutans because the number of S. mutans was decreasing.

S. milleri is the major organism of the gingival crevice. No studies are reported regarding the contamination of toothbrush by this organism. The present study showed the presence of this organism in high numbers in the sample after the use of a self-contaminated brush and there was a decrease following the use of a "single-use" toothbrush. The decrease is minimal probably because of the constant source from the gingival crevicular fluid to the plaque during its formation.

The present study also showed the presence of Candida in the plaque. Contamination of the toothbrush with Candida has been shown by Glass et al. [8] and Taji et al., [3] and the present study supports these studies because by changing the toothbrush, the candidal count in the plaque decreased significantly. Thus, in the present study, it was observed that the quantity of microbes present on the plaque decreased significantly by changing the toothbrush after every use.


The toothbrush has a significant role to reintroduce microorganisms into the oral cavity. Although it is not feasible to change the toothbrush everyday, it may be a sound practice to change the toothbrush as frequently as possible. Toothbrushes should be changed at least once a month. Also, an easy and effective method of disinfecting toothbrushes has a role in reducing the plaque flora.


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