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ORIGINAL ARTICLE
Year : 2015  |  Volume : 13  |  Issue : 4  |  Page : 378-383

Effects of tongue cleaning on plaque and salivary mutans streptococci levels: A randomized controlled trial


1 Department of Public Health Dentistry, Government Dental College and Research Institute, Bengaluru, Karnataka, India
2 Department of Microbiology, Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India

Date of Web Publication7-Dec-2015

Correspondence Address:
Kochiyil Chacko Jacob
Department of Public Health Dentistry, Government Dental College and Research Institute, Room No. 9, Fort, Bengaluru - 560 002, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2319-5932.171184

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  Abstract 

Introduction: Tongue cleaning has been shown to be effective in preventing plaque formation and reducing oral mutans streptococci (MS) when used in combination with other oral hygiene procedures. However, correlation between MS counts and plaque levels remains to be demonstrated. Aim: To evaluate the effect of tongue scraping and tongue brushing on salivary MS and plaque levels. Materials and Methods: A triple-blind three arm randomized controlled parallel-group trial was carried out among 54, 12–15-year-old boys in a residential school in Bengaluru city. The study participants were randomly allocated into Group A (toothbrushing and tongue scraping; n = 19), Group B (toothbrushing and tongue brushing; n = 18) and Group C (only toothbrushing; n = 17). The clinical procedure included a collection of saliva and recording of plaque index at baseline, 10th and 21st day. Salivary MS counts were determined using mitis salivarius bacitracin Agar media. ANOVA, Wilcoxon's signed-rank sum test, Mann–Whitney U-test and Spearman's correlation test were performed on log-transformed CFU/mL of MS.
Results: The tongue scraping and tongue brushing groups showed statistically significant reductions in salivary MS counts after 10 days (4.76 ± 0.54) (4.79 ± 0.44) and 21 days (4.50 ± 0.44) (4.41 ± 0.57) respectively when performed along with toothbrushing. However, differences between the interventions were not statistically significant. Furthermore, there was no statistically significant reduction in plaque levels after 10 and 21 days.
Conclusions: Tongue scraping and tongue brushing were equally effective in reducing salivary MS counts when used in combination with toothbrushing, however, their effect on reducing plaque levels was not significant. Hence, tongue cleaning is recommended as an adjunct to toothbrushing.

Keywords: Dental plaque, mutans streptococci, saliva, tongue brushing, tongue scraping


How to cite this article:
Jacob KC, Yashoda R, Puranik MP, Bano A. Effects of tongue cleaning on plaque and salivary mutans streptococci levels: A randomized controlled trial. J Indian Assoc Public Health Dent 2015;13:378-83

How to cite this URL:
Jacob KC, Yashoda R, Puranik MP, Bano A. Effects of tongue cleaning on plaque and salivary mutans streptococci levels: A randomized controlled trial. J Indian Assoc Public Health Dent [serial online] 2015 [cited 2020 Dec 2];13:378-83. Available from: https://www.jiaphd.org/text.asp?2015/13/4/378/171184


  Introduction Top


The oral surfaces are colonized by over 500 bacterial species and the tongue has the largest bacterial load of any oral tissue and makes the greatest contribution to the bacteria found in saliva and plaque. The papillary structure of the tongue dorsum forms a unique ecological oral site that provides a large surface area favoring the accumulation of oral debris and microorganisms. More than 100 bacteria may be attached to a single epithelial cell on top of the tongue, whereas only about 25 bacteria are attached to each cell in other areas of the oral cavity.[1]

It has been suggested that tonsils, teeth and gingiva can be colonized by tongue bacteria, which originate, especially from the posterior region.[2] Studies have also shown a significant co-relation between the prevalence of mutans streptococci (MS) in saliva and its prevalence on the dorsum of the tongue.[3] Further, a highly significant relationship between salivary MS and dental caries experience has been demonstrated.[4]

Although tongue brushing and tongue scraping have been practiced for hundreds of years, they are still not completely appreciated by the public. Toothbrushing alone is effective in reducing bacterial counts in the mouth, but not dramatically. Tongue cleaning seems to have a more remarkable effect on the salivary levels of caries - causing bacteria such as MS.[1]

Studies suggest that oral hygiene measures should include dorsum of the tongue, especially in high-risk patients, who have endogenously high levels of MS in the oral cavity. Earlier studies have shown, tongue cleaning (tongue scraping and tongue brushing) as an effective adjunct to toothbrushing in preventing plaque formation and reducing oral MS.[1] However, relationship between MS counts and plaque levels were not determined in these studies.

Hence, the study was conducted with the aim to evaluate whether supplementary oral hygiene measures like tongue brushing and tongue scraping can be used as an adjunct to toothbrushing in reducing salivary MS counts and plaque levels. Furthermore to explore the relationship between MS counts and plaque levels if any. It was hypothesized that there is no difference between tongue scraping and tongue brushing in reducing salivary MS counts and plaque levels.


  Materials and Methods Top


This study adopted a triple-blind three arm randomized controlled parallel research design. The study was conducted from July 2014 to September 2014. The study population consisted of 12–15-year-old boys studying in a residential school in Bengaluru city. Ethical clearance was obtained from the Institutional Ethics Committee before commencing the study. Necessary permission was obtained from the principal of the residential school, to conduct the study. Written informed consent from the parents/local guardians and assent from the study participants were obtained. A pilot study was conducted among 10 children to check the feasibility of the study and to calculate the sample size. Sample size of 54 was obtained while maintaining a statistical power of 90% with 95% confidence level, 5% margin of error (E).

Inclusion criteria

  • Age group of 12–15 years
  • Decayed missing filled surfaces (DMFS) ≥1
  • Subjects adhering to daily toothbrushing routine (using toothbrush and toothpaste) and practicing no other oral hygiene measures, either professional or home based, other than the requisites of the research project
  • Cooperation and acceptance of the mechanical method of tongue cleaning.


Exclusion criteria

  • History of antibiotic usage during the past 1 month
  • Use of mouthwash
  • Orthodontic appliance worn
  • Abscess, draining sinus, cellulitis, or other conditions requiring emergency dental treatment
  • Medical/hereditary condition or long-term/recent/current regimen of medication that can affect salivary flow or necessitate diet modification.


To obtain the sample size, a total of 382 school children were evaluated based on inclusion and exclusion criteria and finally 54 children were enrolled into the study [Figure 1]. Investigator number 2 coded the study subjects from 1 to 54. The subjects were then randomly allocated into three groups, Group A, Group B, Group C using online randomization software (www.randomisation.com).[5] This was done to ensure that the investigator number 1 was blinded regarding the group assignment of the subjects.
Figure 1: Flowchart - *Plaque level estimation, salivary sample collection and microbiological analysis were carried out in Group A, B and C at baseline, 10th day and 21st day

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Group A – toothbrushing + tongue scraping (along with routine toothbrushing they had to scrape the dorsum of tongue using a tongue scraper during the study period); Group B - toothbrushing + tongue brushing (along with routine toothbrushing they had to use a soft bristle toothbrush to clean the dorsum of the tongue); Group C - no intervention (control).

At the beginning of the study, investigator number 2 distributed the additional oral hygiene aids (tongue scraper/tongue brush) to the participants according to the groups allocated. No attempt was made to change the standardized toothpaste being provided to the participants by the institution. All the respective groups received Tongue Cleaning Instructions [Box 1 [Additional file 1]].

All the study participants were asked to perform the procedures twice daily (once in the morning after breakfast and once after dinner). The study participants were monitored by a trained supervisor to ensure that all the participants were performing the oral hygiene procedures as advised.

The data were collected using a specially designed proforma. At baseline demographic details, oral hygiene practices and diet history were collected. Assessment of plaque index followed by a recording of salivary MS counts was performed at baseline, 10th and 21st day.

The investigator number 1 was trained and calibrated in the Department of Public Health Dentistry, prior to the start of the study to ensure reliability. The Kappa co-efficient value (k) for intra-examiner reliability for the investigator was 0.86. The clinical oral examination was carried out by the investigator number 1 under artificial light. Participants were examined on a chair and recording was done by a trained personnel. Autoclaved instruments were used, and standard infection control procedure was observed throughout the study period.

Dental plaque levels were assessed using plaque index by Silness and Löe (1964)[6] at the same instance after the collection of saliva. Dental plaque was scored by investigator number 1 on individual plaque assessment forms. Separate plaque assessment forms were used at each follow-up.

Paraffin-stimulated whole saliva samples were collected at baseline, 10th day and 21st day. Saliva samples were collected in the midmorning with no eating, drinking (except water) for at least 2 h prior to sampling. The participants were asked to chew a piece of paraffin wax for 2 min after which they expectorated the accumulated saliva into the sterile container. No transport medium was used, as culturing was performed within half an hour of a collection of the samples.[1]

The samples so collected were subjected to microbiological analysis. Each saliva sample was vortexed vigorously for 30 s to ensure a representative mixture throughout the sample prior to the preparation of dilutions and plating. The medium used for culturing salivary MS was mitis salivarius bacitracin agar.[7] 100 µl of the vortexed salivary sample were pipetted out using a standard 100 µl pipette, and serial dilutions prepared. A 100 µl volume from each of the dilutions was pipetted onto separate agar plates and evenly spread onto the agar surface using sterile spreaders. The preparation of dilutions and agar plating was carried out within an inoculating hood. The plates were then incubated at 37°C for 48 h under 5–10% CO2. MS colonies on each plate were enumerated. All plates were processed and examined by a single investigator (microbiologist) who was also blinded.[8] There was no loss to follow-up during the study period.

All the data were entered into a database on Microsoft Excel, checked for normalcy and analyzed using SPSS software (version 21; SPSS Inc., Chicago, IL, USA). Comparisons were made within groups and between groups from baseline to day 10 and day 21 for salivary MS counts and plaque scores followed by correlation. Two-way ANOVA, Wilcoxon's signed-rank sum test, Mann–Whitney U-test, and Spearman's correlation test were used. A P < 0.05 was considered as significant.


  Results Top


Out of 54 study participants, Group A (toothbrushing + tongue scraping) comprising 19 individuals had a mean age of 13.26 ± 2.47 years; Group B (toothbrushing + tongue brushing) comprising 18 individuals had a mean age of 14.00 ± 1.94 years and Group C (no intervention) comprising 17 individuals had a mean age of 13.94 ± 2.41 years. The groups had similar DMFS at baseline [Table 1].
Table 1: Mean age and caries experience of study groups

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A significant difference (intragroup) was observed in MS counts between baseline and day 10, baseline and day 21 and between day 10 and day 21 for Groups A and B (P < 0.001). While no significant difference between different periods of follow-up were found in Group C [Table 2].
Table 2: Mean salivary MS counts (log values) at baseline, day 10 and 21 of study groups

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There was no significant difference (intergroup) between the groups at baseline and day 10. Significant difference was observed in MS counts between Group A and Group C, Group B and Group C on day 21 (P < 0.05) [Table 2] and [Figure 2].
Figure 2: Mean salivary mutans streptococci counts (log values) at baseline, day 10 and 21 of study groups

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There was no statistically significant difference between the groups and within the groups at baseline, day 10 and day 21 for mean plaque scores [Table 3].
Table 3: Mean plaque scores at baseline, day 10 and 21 of study groups

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There was no statistically significant correlation between MS counts and dental plaque scores at baseline, 10th day and 21st day in all three study groups [Table 4].
Table 4: Correlation between MS and plaque scores

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  Discussion Top


Tongue brushing and scraping have been used since prehistoric times in India, and many ancient religions emphasized cleanliness of the entire mouth including the tongue. The ancient Hindus also used tongue scrapers with sharp curved edges made of silver, gold, copper, tin, or brass. The "Datana" or Indian toothbrush made of a tree twig from an aromatic plant was used after brushing as a tongue scraper. This procedure was used twice a day.[1]

Saliva enters the mouth essentially sterile from the salivary glands but expectorated saliva contains over 10[8] cultivable CFU per ml.[1] This means that large numbers of bacteria are constantly being shed into the saliva from the oral surfaces. The contributions of various surfaces would approximate the size of their surface areas with tongue making the greatest contribution and teeth perhaps only a 5% contribution.[1]

It has also been well established that increased bacterial growth on the tongue is the reason for increased numbers of bacteria in the saliva.[1] High numbers of Streptococcus mutans were repeatedly found on the dorsum of the tongue after thorough scrapings.[9] Moreover, another study found a significant correlation between the prevalence of S. mutans in saliva and its prevalence on the dorsum of the tongue.[10] Significant immediate reduction in salivary S. mutans after professional tooth cleaning and tongue scraping was also noted.[11]

Age is a critical factor in subject selection for many reasons, of which the most important is the number of tooth surfaces at risk. Subjects with a mean age of approximately 13 years were chosen because they were entering a period of high caries activity, with the eruption of many permanent teeth.[12] The study was conducted in a residential school for boys, and therefore, female subjects could not be included. However, epidemiological studies in caries prevalence have not shown any significant difference in the caries susceptibility of boys and girls at an average age.[1] This study was conducted for a period of 21 days among 54, boys which is in line with previous studies.[1],[13]

The frequency of exposure to a cariogenic diet and the form of intake appear to be important factors in the development of dental caries.[12] The trial was conducted in a residential school, and all the subjects had the same diet.

All the study participants used a toothbrush and toothpaste to clean their teeth. The school supplies the material required to maintain personal hygiene including oral hygiene to the students. The interventions in this study were tongue scraping and tongue brushing that were similar to those in previous studies [1],[13],[14] and had been given the best chance of proving their efficacy against salivary MS and dental plaque since it was monitored in a residential school.

Most of the study participants in all the groups had visited a dentist with the proportion being maximum in Group C (76%). This indicates that the majority of the students had the access and utilized some form of dental care.

Salivary samples were collected with no eating or drinking for 2 h prior because saliva samples collected immediately after diet may interrupt the microbial level of the oral environment.[15] Since, the results of the tests performed on unstimulated saliva are less reliable than those performed on stimulated secretion, paraffin-stimulated whole saliva samples were collected.[1]

Group A, B, and C were assessed at baseline, 10th day and 21st day for salivary MS counts and dental plaque scores whereas in the previous studies either MS counts [1],[14] or plaque scores were assessed.[13],[16]

Group A and B exhibited statistically significant reductions in salivary MS counts when baseline values were compared with postintervention values after day 10 and day 21 while the control group did not differ significantly, similar to a previous study. There were no statistically significant differences between the three groups at baseline. At the end of 21 days, tongue scraping and tongue brushing were equally effective in reducing colony counts. This is comparable to a previous Indian study conducted by Rupesh et al.[1] However another study reported statistically insignificant differences in bacterial load (Streptococcal counts) after tongue scraping based on 1 time tongue scraping with sampling done before and after the tongue scraping procedure.[9]

There was no significant difference in mean plaque scores (intragroup and intergroup) at baseline, 10th day and 21st day. This was probably due to the fact that the participants had "good" to "fair" plaque scores at baseline and much improvement could not be recorded within a span of 21 days. These findings are contrary to those found in the previous study by Winnier et al. in which a statistically significant reduction in plaque levels was observed on day 10 and day 21 in the tongue scraping and tongue brushing groups in comparison to the group in which no intervention had been carried out.[13]

Studies reported in the literature have either considered MS or plaque as outcome indicators of tongue cleaning methods. The current study evaluated both these variables and checked for their relationship if any. However, no statistically significant correlation could be established between MS counts and dental plaque scores at baseline, 10th day and 21st day in all three study groups. This is probably because the significant change was noted only in MS counts and not plaque levels during the trial period. It appears that MS count is a sensitive indicator of the effects of tongue cleaning in comparison to plaque levels.

Dental caries is a dietary carbohydrate–modified infectious disease because the major causative factors are believed to be local in nature.[13] As diet was controlled in our study, the different tongue cleaning procedures were provided an ideal opportunity to demonstrate their efficacy against MS. Further, it was possible to standardize the study instruments and monitor the interventions since it was performed in a residential school. The study groups selected were from the same residential school. Therefore, the Hawthorne effect cannot be ruled out. In addition, none of the participants had any compliance problems or reported any untoward incidents (harms) at any time during the study after using either the scraper or the brush.

This study was conducted in a residential boys' school, for a shorter duration. Further studies involving both the genders, wider age range, longer duration, and in the general population is suggested. The oral hygiene measures used in the present study were simple, easy to use and may be recommended for children as a part of routine oral hygiene procedures. Even in the absence of a tongue scraper and using only a toothbrush it is possible to achieve improved oral hygiene at little or no extra cost.

Hence, this study was a novel attempt designed to simulate a realistic home regimen in which the subjects either performed tongue scraping or tongue brushing daily while continuing their normal twice daily toothbrushing routine. In this context, it is noteworthy that the reductions in salivary MS in our study occurred in addition to the effects of twice daily toothbrushing.


  Conclusion Top


The tongue scraping and tongue brushing groups showed statistically significant reductions in salivary MS counts after 10 days and also after 21 days when performed along with toothbrushing. The difference between the interventions was not statistically significant. The tongue scraping and tongue brushing groups showed no statistically significant reduction in plaque. No relation was found between MS counts and dental plaque levels.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Rupesh S, Winnier JJ, Nayak UA, Rao A, Reddy V, Peter J. The comparative evaluation of the effects of tongue cleaning on salivary levels of mutans streptococci in children. Int J Dent Hyg 2012;10:107-12.  Back to cited text no. 1
    
2.
Danser MM, Gómez SM, Van der Weijden GA. Tongue coating and tongue brushing: A literature review. Int J Dent Hyg 2003;1:151-8.  Back to cited text no. 2
    
3.
White GE, Armaleh MT. Tongue scraping as a means of reducing oral mutans streptococci. J Clin Pediatr Dent 2004;28:163-6.  Back to cited text no. 3
    
4.
Klock B, Krasse B. A comparison between different methods for prediction of caries activity. Scand J Dent Res 1979;87:129-39.  Back to cited text no. 4
    
5.
Available from: http://www.randomisation.com. [Last accessed on 2014 Jun 24 at 10:20 PM].  Back to cited text no. 5
    
6.
Silness J, H. Periodontal disease in pregnancy. II. Correlation between oral hygiene and periodontal condition. Acta Odontol Scand 1964;22:112-135.  Back to cited text no. 6
    
7.
Gold OG, Jordan HV, van Houte J. A selective medium for Streptococcus mutans. Arch Oral Microbiol 1973;18:1357-64.  Back to cited text no. 7
    
8.
Wan AK, Seow WK, Walsh LJ, Bird PS. Comparison of five selective media for the growth and enumeration of Streptococcus mutans. Aust Dent J 2002;47:21-6.  Back to cited text no. 8
    
9.
Menon MV, Coykendall AL. Effect of tongue scraping. J Dent Res 1994;73:1492.  Back to cited text no. 9
    
10.
Lindquist B, Emilson CG. Distribution and prevalence of mutans streptococci in the human dentition. J Dent Res 1990;69:1160-6.  Back to cited text no. 10
    
11.
Axelsson P, Kristoffersson K, Karlsson R, Bratthall D. A 30-month longitudinal study of the effects of some oral hygiene measures on Streptococcus mutans and approximal dental caries. J Dent Res 1987;66:761-5.  Back to cited text no. 11
    
12.
Nikiforuk G, editor. Nutrition, diet (local substrate) and dental caries. In: Understanding Dental Caries-1. Etiology and Mechanisms. 1st ed. New York: Karger; 1985. p. 182-7.  Back to cited text no. 12
    
13.
Winnier JJ, Rupesh S, Nayak UA, Reddy V, Prasad Rao A. The comparative evaluation of the effects of tongue cleaning on existing plaque levels in children. Int J Clin Pediatr Dent 2013;6:188-92.  Back to cited text no. 13
    
14.
Gondhalekar R, Richard KM, Jayachandra MG, Aslam S, Reddy VN, Barabde AS. Effect of tongue cleaning methods and oral mutans streptococci level. J Contemp Dent Pract 2013;14:119-22.  Back to cited text no. 14
    
15.
Kleber CJ, Putt MS, Smith CE, Gish CW. Effect of supervised use of an alum mouthrinse on dental caries incidence in caries-susceptible children: A pilot study. ASDC J Dent Child 1996;63:393-402.  Back to cited text no. 15
    
16.
Gross A, Barnes GP, Lyon TC. Effects of tongue brushing on tongue coating and dental plaque scores. J Dent Res 1975;54:1236.  Back to cited text no. 16
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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