Abstract
Objectives
The significance of performing tongue brushing is uncertain and lacks sufficient clinical evidence. This study was conducted to assess the existing practices on tongue brushing among school children and their parents and its effect on optimal levels of salt and sugar concentration, the development of dental caries and body mass index among children.
Results
Of 191 students (52.9% male), 178 responded; 134 (57.3%) reported tongue brushing. Among 313 parents, 54.5% were female and 283 (91.6%) brushed. Initiation was mainly maternal (68.4%) or paternal (12.0%); only 3.3% of parents cited professional advice. Salt taste thresholds were identical between groups (median 1.5 g/200 mL); means were slightly higher in brushers (3.14 vs. 3.00; p = 0.389). Sugar thresholds were also equivalent (means 3.25 vs. 3.09; NS). BMI correlated weakly with brushing score (r = 0.143, p > 0.05). Sugar taste concentration showed a negative, non-significant correlation (r = − 0.112, p = 0.150). CPITN scores were higher in non-brushers, without significance.
Conclusion
Tongue brushing is a widely practiced habit, primarily adopted through parental influence rather than clinical advice. However, no significant associations were observed with sugar/salt taste thresholds, BMI, dental caries, or periodontal health. While tongue brushing may reduce halitosis and contribute to oral comfort. It should be promoted as an adjunctive, not primary, oral hygiene practice. Further longitudinal and interventional studies are warranted.
Keywords: Tongue brushing, Oral hygiene, Taste perception, Body mass index (BMI), Dental caries, Periodontal health
Introduction
The tongue functions as the primary organ of taste, having specialized gustatory receptors responsible for detecting different taste perceptions. Similar to other epithelial tissues, the lingual mucosa can respond to persistent irritation by undergoing hyperkeratinisation of the dorsal surface. Kobayashi J et al. found that chronic excessive brushing of the mid-lateral dorsal tongue may reduce taste buds and impair taste sensitivity [1]. This physiological adaptation may reduce the taste sensitivity, potentially prompting individuals to consume excessive amounts of sugar and salt to compensate for diminished gustatory perception. Consequently, this behavior of increasing salt and sugar intake is likely to contribute to the onset of non-communicable diseases (NCDs) such as hypertension [2–5] and diabetes mellitus [6, 7] along with cardiovascular, neurological, and renal complications. Regular tongue brushing may also impact oral health by reducing the risk of dental caries [8, 9] and periodontal disease [10], and may have influenced reducing body mass index (BMI) [11].
However, several studies indicated that short term tongue brushing or scraping significantly reduced both mutans streptococci and lactobacilli counts, and also improved oral and systemic health [12, 13], and [14].
Despite existing literature, rarely studies have explored the relationship between tongue brushing and dietary behaviors, including sugar and salt consumption, body mass index (BMI), and the development of dental or systemic diseases. Given the established associations between high salt intake and hypertension, and excessive sugar intake and type II diabetes mellitus, further research is warranted to explore whether tongue brushing affects dietary preferences and health behaviors, and whether mucosal alterations contribute to systemic disease risk. This study aimed to investigate the effect of tongue brushing on individual optimal sensitivity to sugar and salt concentrations, the development of dental caries, periodontal disease, and body mass index (BMI), as well as to assess existing knowledge regarding tongue brushing among school children aged 14–19 years and their parents or guardians.
Methods
Study design and setting
This descriptive cross-sectional study was approved by the Ethics Review Committee of the Faculty of Medicine, University of Kelaniya. It was conducted among students aged 14–19 years attending dental treatment and annual check-ups at a school dental clinic, Batuwatta Maha Vidyalaya, Sri Lanka and their parents or guardians. This age group of students was selected based on their ability to comprehend the self-administered oral health questionnaire and the examination procedures.
Data collection tools
Parents were provided with participants’ information sheet and consent forms. They completed self-administered questionnaires on household sugar and salt consumption and dental habits, which were distributed through the students, two weeks prior to the clinical assessment and collected at the clinic visit. Procedures were informed and informed consent was obtained from the students. They completed a seven-day sugar recall and an oral habits questionnaire, and underwent height and measurements, dental examination, and salt and sugar sensitivity testing to determine individual optimal taste concentrations.
Findings were recorded using pre planned data sheets and content validity was assessed using 10 participants for each category and were not included in the study.
The data collection process occurred over 1 year from January 2020 to March 2021.
Assessment of BMI of school children
Height and weight were measured by the investigator using calibrated scales, and body mass index (BMI) was calculated.
Assessment of salt and sugar concentrations of school children
Average daily sugar and salt consumption was assed using a standardized research-specific method that incorporated both direct and parental estimates.
Optimum salt and sugar sensitivity
To standardize dietary conditions prior to taste testing, students were instructed to consume a traditional Sri Lankan breakfast at least 80 min before the clinical assessment. Thereafter, only water was permitted until the examination to allow oral pH normalization in accordance with the Stephan curve model [15].
To minimize the effect of toothpaste flavor on tongue sensitivity, sensory testing was performed at least two hours after morning tooth brushing, which was assumed to have occurred before 7:00 a.m. in preparation for the 7:30 a.m. school start.
For taste assessment, participants rinsed their mouths three times with plain water before tasting distilled water to establish baseline neutrality. They were then presented with incrementally concentrated salt solutions (0.5 g/200 ml, 1.0 g/200 ml, 1.5 g/200 ml, 2.0 g/200 ml, 2.5 g/200 ml, and 3.0 g/200 ml), rinsing with water and re-tasting distilled water between concentrations, until identifying their optimal salt concentration. The same procedure was repeated for sugar solutions to determine optimal sweetness. Based on WHO guidelines [16, 17], participants were classified into optimal, moderately high, or high salt and sugar sensitivity categories.
Dental examination
Details on recent teeth, Decayed, Missing, and Filled Teeth (DMFT) index, Community Periodontal Index of Treatment Needs (CPITN) [18] and General oral health findings were recorded as part of a routine dental examination.
Sample size and sampling method
The study included 191 students aged 14–19 years who attended the dental clinic, along with 313 of their parents/guardians. Exclusion criteria were regular betel chewing, smoking, alcohol consumption, diagnosed diabetes with altered taste sensation, recent oral thermal burns, use of mouthwash, or intake of any medication within 14 days prior to examination.
Ethical consideration
Ethical approvalwas obtained from the Ethics Review Committee, Faculty of Medicine, University of Kelaniya, Sri Lanka. Participants were informed of the study’s purpose, procedures, and their rights, and written informed consent was obtained. The study adhered to ethical guidelines, ensuring confidentiality, anonymity, and secure storage of personal data, used exclusively by the research team.
Data analysis
Data was entered in the SPSS version 20 software package and descriptive data analysis was done. During the statistical analysis type1 error rate (or alpha) was set at 0.05.
Results
Students’ data
Demography details of the students.
Age and sex distribution
The study included 191 students (ages 14–19; mean: 16.5 ± 1.2 years; median: 16, IQR: 2) years. The age of the student was not recorded by ten (4.2%) of the students. Male students consist of 52.9% (101) of the participants. (Fig. 1)
Fig. 1.
Distribution of age among students
Body mass index
Height and weight measurements were obtained from 178 students. The calculated body mass index (BMI) ranged from 11.2 to 38.6 kg/m², with a mean of 19.9 ± 4.3 kg/m². (Fig. 2).
Fig. 2.
Distribution of Body Mass Index among students
Practice of brushing teeth and tongue
Of the 177 students who responded, 43.5% reported brushing teeth once daily and 55.4% twice daily. Fourteen students did not respond. (Table 1).
Table 1.
Reported daily frequency of brushing teeth by students
| Frequency of brushing teeth | Count (Percent) |
|---|---|
| Once | 77 (43.50%) |
| Twice | 98 (55.37%) |
| More than twice | 2 (1.13%) |
| Total | 177 (100.00%) |
Of the 178 students who responded, 134 (75.3%) reported regularly brushing their tongue. (Fig. 3)
Fig. 3.
Practice of tongue brushing among students
Among the 134 students who reported tongue brushing, 133 provided information on frequency. Of these, 68 (51.1%) brushed twice daily and 62 (46.6%) once daily and one student did not respond. (Table 2)
Table 2.
Reported daily frequency of brushing tongue by students
| Frequency of brushing tongue | Count (percent) |
|---|---|
| Once | 62 (46.62%) |
| Twice | 68 (51.13%) |
| More than twice | 3 (2.26%) |
| Total | 133 (100.00%) |
The median duration of tongue brushing per session was 2 min. (Fig. 4)
Fig. 4.
Time spent brushing tongue per occasion among students
Among students who brushed their tongue, 130 (98.5%) used a toothbrush. One student (0.8%) used a finger, one (0.8%) used a tongue scraper, and two did not record the instrument used. Most students (76.3%) began tongue brushing before the age of 10, while 31 (23.7%) initiated the practice at or after age 10. Three students did not respond. (Table 3)
Table 3.
Age of onset of tongue brushing among students
| Age category | Count (percent) |
|---|---|
| 6–9 years | 100 (76.34%) |
| 10–13 years | 27 (20.61%) |
| 14–19 years | 4 (3.05%) |
| Total | 131 (100.00%) |
According to students, tongue brushing was most often initiated by their mother (91, 68.4%) or father (16, 12.0%), while 26 (19.5%) reported starting the practice on their own (Fig. 5).
Fig. 5.
The main person that advised the student to brush tongue
Estimated salt and sugar consumption
Average daily salt intake, estimated from parental household reports, ranged from 1.7 to 28.6 g, with a mean of 7.9 ± 4.2 g. The distribution of salt consumption levels is shown in Fig. 6.
Fig. 6.
Distribution of estimated daily salt consumption among students
Average daily sugar intake, estimated from parental reports and a 7-day student recall, ranged from 11.9 to 227.4 g, with a mean of 79.7 ± 33.2 g. The distribution of estimated sugar consumption is shown in Fig. 7.
Fig. 7.
Distribution of estimated daily sugar consumption among students
Optimum salt and sugar taste concentration
Salt taste testing was completed by 187 students (97.9%). The median optimal salt concentration identified was 1.5 g/200 ml. The distribution of optimal salt taste levels is shown in Fig. 8.
Fig. 8.
Optimum salt taste concentration identified by the students
Sugar taste testing was completed by 185 students (96.9%), with a median optimum sugar concentration of 1.5 g/200 ml. (Fig. 9)
Fig. 9.
Optimum sugar taste concentration identified by the students
Calculation of tongue brushing score
Tongue brushing was initially recorded as a binary variable (present/absent). To quantify long-term exposure, a composite score was derived using:
Time spent brushing (1–5 min): scored 1–5.
Frequency per day once (1), twice (2), more than twice (3).
Starting age 14–19 years (1), 10–13 years (2), 6–9 years (3).
Participants who did not brush their tongue received a score of 0. For others, the score was calculated by multiplying the values above, with a maximum possible score of 45.
Relationship between tongue brushing and optimal taste levels
Optimal taste concentration was recorded as one of six increasing ordinal levels. To analyse its relationship with tongue brushing habits, the non-parametric Mann-Whitney U test was used. (Table 4, 5)
Table 4.
Association between tongue brushing and optimal salt taste concentration
| Group | Median (interquartile range) |
Mean (standard deviation) |
Mann-Whitney U test asymptotic significance |
|---|---|---|---|
| Students who brush their tongue | 3.00 (2.00) | 3.14 (1.06) | p = 0.389 |
| Students who do not brush their tongue | 3.00 (2.00) | 3.00 (1.09) |
Table 5.
Association between tongue brushing and optimal sugar taste concentration
| Group | Median (interquartile range) |
Mean (standard deviation) |
Mann-Whitney U test asymptotic significance |
|---|---|---|---|
| Students who brush their tongue | 3.00 (2.00) | 3.25 (1.23) | p = 0.522 |
| Students who do not brush their tongue | 3.00 (2.00) | 3.09 (1.17) |
As shown in Tables 4 and 5, the median optimal concentrations for both salt and sugar tastes were identical between those who brushed their tongue and those who did not. Mean values were slightly higher among tongue brushers (salt: 3.14 vs. 3.00; sugar: 3.25 vs. 3.09), but differences were not statistically significant (salt: p = 0.389; sugar: p = 0.522).
Using Spearman’s correlation (Table 6), tongue brushing score showed a near-zero, non-significant correlation with optimal salt concentration (r = 0.007, p = 0.923) and a weak negative, non-significant correlation with sugar concentration (r = -0.112, p = 0.150).
Table 6.
Correlation between tongue brushing score and optimal taste concentration
| Variable Correlated with tongue brushing score | Spearman’s correlation coefficient | Statistical significance |
|---|---|---|
| Optimal salt taste concentration | 0.007 | p = 0.923 |
| Optimal sugar taste concentration | -0.112 | p = 0.150 |
Oral examination findings of the participants
DMFT data were available for 184 students, and periodontal examination results were recorded for 182 students.
Decayed Teeth Count ranged from 0 to 6; median was 0 (Fig. 10).
Missing Teeth Ranged from 0 to 8; median was 0 (Fig. 11).
Filled Teeth Ranged from 0 to 6; median was 0 (Fig. 12).
DMFT Score Ranged from 0 to 11; median value was 0 (Fig. 13).
Fig. 10.
Distribution of the decayed teeth count among students
Fig. 11.
Distribution of the missing teeth count among students
Fig. 12.
Distribution of the filled teeth count among students
Fig. 13.
Distribution of the DMFT value among students
The CPITN index, based on periodontal examination, ranged from 0 to 8, with a median value of 1 (Fig. 14).
Fig. 14.
Distribution of the CPTIN index value among students
Relationship between tongue brushing and clinical oral health indices of students
Clinical examination scores were analysed as ordinal variables using the Mann–Whitney U test to assess their association with tongue brushing (binary variable). As shown in Table 7, median decayed teeth counts did not differ between groups, with a slightly higher mean in the tongue-brushing group; the difference was not statistically significant.
Table 7.
Association between tongue brushing and decayed teeth count
| Group | Median (interquartile range) |
Mean (standard deviation) |
Mann-Whitney U test asymptotic significance |
|---|---|---|---|
| Students who brush their tongue | 0.00 (1.00) | 0.64 (1.17) | p = 0.951 |
| Students who do not brush their tongue | 0.00 (1.00) | 0.62 (1.08) |
Median missing teeth counts were identical between groups, while the mean was slightly higher among tongue brushers; this difference was not statistically significant (Table 8).
Table 8.
Association between tongue brushing and missing teeth count
| Group | Median (interquartile range) |
Mean (standard deviation) |
Mann-Whitney U test asymptotic significance |
|---|---|---|---|
| Students who brush their tongue | 0.00 (0.00) | 0.29 (0.92) | p = 0.872 |
| Students who do not brush their tongue | 0.00 (0.00) | 0.24 (0.62) |
For filled teeth, median counts were equal, but the mean was higher in the non-tongue-brushing group; the difference was not statistically significant (Table 9).
Table 9.
Association between tongue brushing and filled teeth count
| Group | Median (interquartile range) |
Mean (standard deviation) |
Mann-Whitney U test asymptotic significance |
|---|---|---|---|
| Students who brush their tongue | 0.00 (0.00) | 0.29 (0.86) | p = 0.982 |
| Students who do not brush their tongue | 0.00 (0.00) | 0.31 (1.02) |
The combined count of decayed, missing and filled teeth, which is the DMFT value showed comparable medians, with a slightly higher mean among tongue brushers, but no significant difference between two groups (Table 10).
Table 10.
Association between tongue brushing and DMFT value
| Group | Median (Interquartile Range) |
Mean (Standard Deviation) |
Mann-Whitney U Test Asymptotic Significance |
|---|---|---|---|
| Students who brush their tongue | 0.00 (2.00) | 1.23 (1.88) | p = 0.931 |
| Students who do not brush their tongue | 0.00 (2.25) | 1.14 (1.68) |
For the periodontal health measure of CPITN index, both mean and median values were higher in the non-tongue-brushing group; however, the difference was not statistically significant. (Table 11)
Table 11.
Association between tongue brushing and CPTIN index
| Group | Median (interquartile range) |
Mean (standard deviation) |
Mann-Whitney U test asymptotic significance |
|---|---|---|---|
| Students who brush their tongue | 1.00 (2.00) | 1.18 (1.09) | p = 0.641 |
| Students who do not brush their tongue | 2.00 (2.00) | 1.21 (0.90) |
Spearman’s correlation was used to assess the relationship between tongue brushing scores and clinical oral health indices. As shown in Table 12, all correlations were statistically non-significant. While filled teeth counts showed a positive correlation with tongue brushing, all other indices exhibited negative correlation coefficients.
Table 12.
Correlation between tongue brushing score and oral health indices
| Variable Correlated with tongue brushing score | Spearman’s correlation coefficient | Statistical significance |
|---|---|---|
| Decayed teeth count | -0.033 | p = 0.666 |
| Missing teeth count | -0.043 | p = 0.577 |
| Filled teeth count | 0.037 | p = 0.632 |
| DMFT value | -0.016 | p = 0.832 |
| CPTIN index | -0.008 | p = 0.919 |
Relationship between tongue brushing and BMI
BMI, as a continuous variable, was compared between tongue brushing and non-brushing groups using an independent sample t-test. The mean BMI was slightly higher in tongue brushers (20.06 vs. 19.55), but this difference was not statistically significant (Table 13).
Table 13.
Association between tongue brushing and BMI
| Group | Mean (Standard deviation) |
Independent samples t-test t value | Two-tailed significance |
|---|---|---|---|
| Students who brush their tongue | 20.06 (4.21) | 0.641 | p = 0.522 |
| Students who do not brush their tongue | 19.55 (4.61) |
Although the tongue brushing score is based on discrete variables, its broad range allows it to be treated as approximately continuous. Thus, Pearson’s correlation was used to assess its relationship with BMI. The correlation was positive (r = 0.143) but not statistically significant (p > 0.05), indicating no significant association (Table 14).
Table 14.
Correlation between tongue brushing score and BMI
| Variable correlated with tongue brushing score | Pearson correlation coefficient | Statistical significance |
|---|---|---|
| Decayed teeth count | 0.143 | p = 0.071 |
Analysis of Parent/ guardian oral habits
Demography
Among 313 parent/guardian respondents, 170 (54.5%) were female. The median age group was 45–50 years (Table 15), and the median education level was completion of the Ordinary Level examination (Fig. 15). Fifteen respondents did not report their education level.
Table 15.
Age category of the parents/guardians
| Age category | Count (Percent) |
|---|---|
| 31–40 years | 51 (16.29%) |
| 41–45 years | 94 (30.03%) |
| 45–50 years | 103 (32.91%) |
| > 50 years | 65 (20.77%) |
| Total | 313 (100.00%) |
Fig. 15.
Distribution of the education level among parents/guardians
Oral brushing habits of parents
According to the responses of the parents, 54 (17.2%) brushed their teeth once a day, while 77.9% (240) brushed twice a day (Table 16).
Table 16.
Reported daily frequency of brushing teeth by parents/guardians
| Frequency of brushing teeth | Count (percent) |
|---|---|
| Once | 53 (17.21%) |
| Twice | 240 (77.92%) |
| More than twice | 15 (4.87%) |
| Total | 308 (100.00%) |
Over 90% of the parents reported that they brushed their tongue (Fig. 16). The majority 65.6% (181) brushed their tongue twice a day. The mean at which parents had started brushing their tongue was 5.6 (standard deviation = 2.5) years. Figure 17 shows the distribution of the parents’ age at starting tongue brushing and (Table 17) shows the daily frequency.
Fig. 16.
Practice of tongue brushing among parents/guardians
Fig. 17.
Distribution of age when starting tongue brushing by parents/guardians
Table 17.
Reported daily frequency of brushing tongue by parents/guardians
| Frequency of brushing tongue | Count (percent) |
|---|---|
| Once | 60 (21.74%) |
| Twice | 181 (65.58%) |
| More than twice | 35 (12.68%) |
| Total | 276 (100.00%) |
According to parent responses, 92.2% (259) used a toothbrush for tongue brushing, while 7.8% (22) used their fingers.
Tongue brushing was mostly self-initiated or influenced by advice from their mother (Table 18).
Table 18.
The person who advised on tongue brushing
| Person | Count (percent) |
|---|---|
| Self | 116 (42.03%) |
| Mother | 131 (47.46%) |
| Father | 19 (6.88%) |
| Dentist | 1 (0.36%) |
| Medical Doctor | 8 (2.90%) |
| Other | 1 (0.36%) |
| Total | 276 (100.00%) |
Of the 312 parents who responded, 12.2% (38) reported diabetes, 7.7% (24) had hypertension, and 1.6% (5) had ischemic heart disease.
Discussion
The present study explored the prevalence of tongue brushing practices among school children and their parents, as well as its potential associations with sugar and salt taste preferences, body mass index (BMI), dental caries, and periodontal health. The findings demonstrated that tongue brushing is a common practice in this population, with a higher prevalence among parents compared to children, but its adoption was primarily influenced by parental modeling rather than clinical advice. Despite widespread use, no statistically significant associations were observed between tongue brushing and sugar or salt thresholds, BMI, caries, or periodontal health.
Our findings corroborate prior literature suggesting that tongue cleaning is primarily practiced for reasons related to halitosis control and oral comfort, rather than for measurable systemic or dental health outcomes [12, 19–25]. Previous studies have reported that tongue cleaning effectively reduces volatile sulfur compounds and microbial load on the dorsum of the tongue [26–29]. However, its impact on clinical indices of dental caries and periodontal disease [30] remains less conclusive. In the present study, although CPITN scores were higher among non-brushers, the differences were not significant, aligning with research that positions tongue brushing as an adjunctive rather than a primary oral hygiene measure [10, 19], and [22].
Interestingly, the study observed no significant relationship between tongue brushing and taste perception of sugar and salt, although non-significant trends indicated slightly higher thresholds among brushers. Kobayashi et al. suggested that tongue brushing could influence taste perception by maintaining fungiform papillae function [1]. Similarly, taste sensitivity has been implicated in dietary behaviors and subsequent risk of obesity and metabolic diseases [5–7]. Our lack of significant associations may be attributable to the cross-sectional design, the limited sensitivity of the taste assessment method, or insufficient duration/intensity of tongue brushing to produce perceptible changes.
The weak, non-significant correlation between tongue brushing and BMI observed here contrasts with studies that have linked reduced taste sensitivity with increased BMI [11]. It is plausible that tongue brushing may support taste bud maintenance, but its effects on dietary intake and body weight require larger longitudinal studies with biochemical and dietary assessments to clarify causality.
From a preventive dentistry perspective, tongue brushing was not associated with reduced caries prevalence in this cohort. This is consistent with evidence that caries is multifactorial, influenced predominantly by sugar intake, salivary flow, fluoride exposure, and bacterial ecology [31, 23]. While tongue cleaning may modestly reduce microbial load [13, 32], its direct contribution to caries prevention appears limited compared with tooth brushing and dietary modifications [31, 25].
Another important observation is the lack of professional influence in initiating tongue brushing habits. Only a small proportion of parents reported adopting the practice based on professional advice, highlighting a gap in preventive counseling. Given that both children and parents mainly relied on cultural or familial transmission of oral hygiene practices, dental health professionals should consider reinforcing evidence-based recommendations about tongue cleaning, particularly its role in reducing halitosis and maintaining oral microbial balance [10, 33].
This study has several limitations. Its cross-sectional design precludes causal inference, and the reliance on self-reported practices may be prone to recall or reporting bias. Moreover, the assessment of sugar and salt thresholds through solution-based tests may not fully capture complex taste dynamics. Future research should include randomized controlled trials with standardized tongue cleaning interventions and long-term follow-up to better establish causality. Integration of microbiome profiling could further elucidate the biological pathways by which tongue brushing may influence oral and systemic health [19, 34, 35], and [22].
Limitations
Data collection was disrupted by the COVID-19 pandemic, which reduced student attendance, heightened anxiety regarding dental procedures, and hindered oral examinations. Consequently, the intended sample size of > 409 student–parent pairs was not achieved, potentially limiting statistical power and generalizability. Furthermore, as this was a descriptive study, participants with incomplete responses were also included.
Conclusion
Tongue brushing is a widely practiced habit, primarily adopted through parental influence rather than clinical advice. However, no significant associations were observed with sugar/salt taste thresholds, BMI, dental caries, or periodontal health. While tongue brushing may reduce halitosis and contribute to oral comfort [12, 19–25, 36], it should be promoted as an adjunctive, not primary, oral hygiene practice. Further longitudinal and interventional studies are warranted.
Acknowledgements
Not applicable.
Author contributions
S.V., K.J., and W.N.S. contributed to the conception and design of the work. S.V., K.J helped with data collection, data interpretation and provided the initial draft of the manuscript. Critical revision of manuscript was done by W.N.S. All authors read and approved the final version of the article.
Funding
Self-funded study.
Data availability
Data sheets are available in excel format. It can be declared whenever necessary.
Declarations
Ethics approval and consent to participate
Ethical approval was obtained from the Ethical review committee, Faculty of Medicine, University of Kelaniya, Sri Lanka. Informed written consent was obtained from participants for voluntary participation and publish anonymous data.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Kobayashi J, Saito T, Ito T, Yoshimura H, Matsuda S, Yoshida H, Fujita R, Sano K. Association of tongue brushing with the number of fungiform taste buds and taste perception: A preliminary study using confocal laser scanning microscopy in combination with a filter-paper disc method. Arch Oral Biol. 2017;84:145–150. doi: 10.1016/j.archoralbio.2017.09.025. Epub 2017 Sep 28. PMID: 28992600. [DOI] [PubMed]
- 2.Bailey MA, Dhaun N. Salt sensitivity: causes, consequences, and recent advances. Hypertension. 2023;81(3):617–29. 10.1161/HYPERTENSIONAHA.123.17959. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Feng YE, Pan S, Verma H, Zheng H, Alviter Plata A, Zubcevic J, Leenen FHH. Central nervous system mechanisms of salt-sensitive hypertension. Physiol Rev. 2025;105(4):1989–2032. 10.1152/physrev.00035.2024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Roura E, Foster S, Winklebach A, Navarro M, Thomas W, Campbell K, Stowasser M. Taste and Hypertension in Humans: Targeting Cardiovascular Disease. Curr Pharm Des. 2016;22(15):2290 – 305. 10.2174/1381612822666160216151545. PMID: 26881437. [DOI] [PubMed]
- 5.Pugnaloni S, Alia S, Mancini M, Santoro V, Di Paolo A, Rabini RA, Fiorini R, Sabbatinelli J, Fabri M, Mazzanti L, Vignini A. A study on the relationship between type 2 diabetes and taste function in patients with good glycemic control. Nutrients. 2020;12(4):1112. 10.3390/nu12041112. PMID: 32316314; PMCID: PMC7230282. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Gondivkar SM, Indurkar A, Degwekar S, Bhowate R. Evaluation of gustatory function in patients with diabetes mellitus type 2. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(6):876 – 80. doi: 10.1016/j.tripleo.2009.08.015. PMID: 19913725. [DOI] [PubMed]
- 7.Shivam V, Kannan S, Harish V. Taste genomics and type 2 diabetes mellitus: a systematic qualitative meta-synthesis. Explor Endocr Metab Dis. 2025;2:101439. 10.37349/eemd.2025.101439. [Google Scholar]
- 8.Clement C. Azodo1, Adebola O. Ehizele1, Agnes Umoh2 Patrick I. Ojehanon2, Osagie Akhionbare2, Robinson Okechukwu3and Lawrence Igbinosa 1 (2010),Tooth brushing, tongue cleaning and snacking behavior of dental technology and therapist students. Libyan J Med, 5(10), 10.3402/ljm.v5i0.5208 [DOI] [PMC free article] [PubMed]
- 9.Mosaico G, Pinna M, Grassi R, Orrù G, Scribante A, Maiorani C, et al. Oral health and caries prevention: how tongue hygiene helps maintain balance of microbiota and overall health in pediatric patients. Children. 2024;11(7):816. 10.3390/children11070816. PMID: 39062265; PMCID: PMC11276146. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.AlBeshri S. Perspectives on tongue coating: etiology, clinical management, and associated diseases — a narrative review. Saudi Dent J. 2025;37:41. 10.1007/s44445-025-00048-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Arianna Vignini F, Borroni J, Sabbatinelli. Sofia Pugnaloni, 1 Sonila Alia, Marina Taus, Luigi Ferrante, 3 Laura Mazzanti, and Mara Fabri 4. (2019). General decrease of taste sensitivity is related to increase of BMI. Dis Markers 10.1155/2019/2978026 [DOI] [PMC free article] [PubMed]
- 12.Almas K. The effect of tongue scraper on mutans Streptococci and lactobacilli in patients with caries and periodontal disease. Odontostomatol Trop. 2005;28(109):5–10. [PubMed] [Google Scholar]
- 13.Gopalakrishnan D. Is the oral hygiene complete without the tongue cleaning? J Indian Soc Periodontol. 2024 Mar-Apr;28(2):153–154. doi: 10.4103/jisp.jisp_258_24. Epub 2024 Aug 31. PMID: 39411740; PMCID: PMC11472967. [DOI] [PMC free article] [PubMed]
- 14. Rajasekaran JJ, Krishnamurthy HK, Bosco J, Jayaraman V, Krishna K, Wang T, Bei K. Oral microbiome: A review of its impact on oral and systemic health. Microorganisms. 2024;12(9):1797. 10.3390/microorganisms12091797. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Susan Higham C, Hope S, Valappil P, Smith. Caries Process and Prevention Strategies: The Stephan Curve. Retrieved August 7,2019 from https://www.dentalcare.com/en-us/professional-education/ce-courses/ce371/the-stephan-curve
- 16.WHO Guideline on Sugar intake for adults and Children. World health organization, Retrieved September 28,2019. from https://apps.who.int/iris/bitstream/handle/10665/149782/9789241549028_eng.pdf?sequence=1
- 17.WHO Guideline on Sodium intake for adults and Children. World health organization, Retrieved September 28,2019 https://iris.who.int/bitstream/handle/10665/77985/9789241504836_eng.pdf
- 18.Rapp GE, et al. Technical assessment of WHO-621 periodontal probe made in Brazil. Braz Dent J. 2002;13(1):61–5. [PubMed] [Google Scholar]
- 19.Taani DS, al-Wahadni AM, al-Omari M. The effect of frequency of toothbrushing on oral health of 14–16-year-olds. J Ir Dent Assoc. 2003;49(1):15–20. [PubMed] [Google Scholar]
- 20.Garcia-Closas R, Garcia-Closas M, Serra-Majem L. A cross-sectional study of dental caries, intake of confectionery and foods rich in starch and sugars, and salivary counts of Streptococcus mutans in children in Spain. Am J Clin Nutr. 1997;66(5):1257–63. [DOI] [PubMed] [Google Scholar]
- 21.Acar B, Berker E, Tan Ç, İlarslan YD, Tekçiçek M, Tezcan İ. Effects of oral prophylaxis including tongue cleaning on halitosis and gingival inflammation in gingivitis patients. Clin Oral Investig. 2019;23(4):1829–36. 10.1007/s0078401826175. [DOI] [PubMed] [Google Scholar]
- 22.van der Sleen MI, Slot DE, van Trijffel E, Winkel EG, van der Weijden GA. Effectiveness of mechanical tongue cleaning on breath odour and tongue coating: a systematic review. Int J Dent Hyg. 2010;8(4):258–68. 10.1111/j.16015037.2010.00479. [DOI] [PubMed] [Google Scholar]
- 23.Danser MM, Mantilla Gómez S, van der Weijden GA. Tongue coating and tongue brushing: a literature review. Int J Dent Hyg. 2003;1(3):151–8. 10.1034/j.16015037.2003.00034. [DOI] [PubMed] [Google Scholar]
- 24.Outhouse TL, AlAlawi R, Fedorowicz Z, Keenan JV. Tongue scraping for treating halitosis. Cochrane Database Syst Rev. 2006;2CD005519. 10.1002/14651858.CD005519.pub2. [DOI] [PubMed]
- 25.Li Y, Lee S, Stephens J, Zhang W, Suprono M, Mwatha A, et al. A randomized, parallel study to assess the effect of three tongue cleaning modalities on oral Malodour. J Clin Dent. 2019;30(Spec No A):A30–8. [PubMed] [Google Scholar]
- 26.Lula ECO, Ribeiro CCC, Hugo FN, Alves CMC, Silva AM. Added sugars and periodontal disease in young adults: an analysis of NHANES III data. Am J Clin Nutr. 2014;100(4):1182–7. 10.3945/ajcn.114.089656. [DOI] [PubMed] [Google Scholar]
- 27.Rupesh S, Winnier JJ, Nayak UA, Rao AP, Reddy V, Peter J. Comparative evaluation of tongue cleaning on salivary levels of mutans Streptococci in children. Int J Dent Hyg. 2012;10(2):107–12. 10.1111/j.16015037.2011.00522.x. [DOI] [PubMed] [Google Scholar]
- 28.Azodo CC, Ehizele AO, Umoh A, Ojehanon PI, Akhionbare O, Okechukwu R, et al. Tooth brushing, tongue cleaning and snacking behavior of dental technology and therapist students. Libyan J Med. 2010;5:5208. 10.3402/ljm.v5i0.5208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Kishi M, Namioka T, Onodera N, Aizawai F, Sekine A, Yonemitsui M. Prevalence of tongue cleaning habit and related factors in healthy individuals in Iwate Prefecture, Japan [Internet]. 2012 [cited 2019 Sep 23]. Available from: https://www.researchgate.net/publication/229405195
- 30.Laleman I, Koop R, Teughels W, Dekeyser C, Quirynen M. Influence of tongue brushing and scraping on the oral microflora of periodontitis patients. J Periodont Res. 2018;53(1):73–9. 10.1111/jre.12479. [DOI] [PubMed] [Google Scholar]
- 31.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(4):378–83. 10.4103/23195932.171184. [Google Scholar]
- 32.Lean MEJ, Te Morenga L. Sugar and type 2 diabetes. Br Med Bull. 2016;120(1):43–53. 10.1093/bmb/ldw03714. [DOI] [PubMed] [Google Scholar]
- 33.Viswanath D, Sabu N. Prevalence of dental caries, the effect of sugar intake and tooth brushing practices in children aged 5–11 years in Bangalore North. SRM J Res Dent Sci. 2014;5(3):155–62. [Google Scholar]
- 34.American Diabetes Association. How your body uses glucose and insulin: about insulin and high blood glucose [Internet]. [cited 2019 Aug 6]. Available from: http://www.diabetes.org/are-you-at-risk/lower-your-risk/highbg.html
- 35.Gulati MS, Gupta L. Clinical evaluation of supplementing tongue brushing to most advocated regime of tooth brushing. J Indian Soc Pedod Prev Dentistry. 1998;16(1):12–6. [PubMed] [Google Scholar]
- 36.Bordas A, McNab R, Staples AM, Bowman J, Kanapka J, Bosma MP. Impact of different tongue cleaning methods on the bacterial load of the tongue dorsum. Arch Oral Biol. 2008;53(Suppl 1):S13–8. 10.1016/S0003-9969(08)70004-. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data sheets are available in excel format. It can be declared whenever necessary.