Abstract
Background:
Smoking and smokeless form of tobacco consumption is highly prevalent among the adult population worldwide. Tobacco use has an adverse effect on oral health. It may contribute to an impaired salivary flow rate and influence salivary pH and taste perception.
Aim:
To evaluate the effects of tobacco on salivary flow rate, salivary pH and taste perception.
Objective:
To evaluate salivary flow rate, pH and taste perception in tobacco chewers and tobacco smokers.
Materials and Method:
Sixty subjects were selected from the patients attending Dental OPD. Group A included 20 subjects who has the habit of chewing tobacco for a minimum period of 5 years. Group B included 20 subjects who has the habit of smoking tobacco for at least a period of 5 years. Group C included 20 healthy individuals who did not have habit of chewing or smoking tobacco, and they formed the control group.
Results:
On comparing salivary pH between tobacco chewers (Group A) and control group (Group C), it was observed that there was not much difference in salivary pH between the groups. The mean value of Group A (tobacco chewers) of salivary pH was calculated as 7.59 with 0.70 SD. For the control group (Group C), the mean value was obtained as 7.42 with 0.96 standard deviation. The independent t-test was applied, and the result was nonsignificant. Similarly, when SFR was evaluated, it was observed that the mean value for SFR of Group A was 1.75 with 0.71 SD, and for the control group, it was 1.51. There was no significant difference in pH between Group A and Group B. A significant reduction in taste perception was observed in smokers as compared to nonsmokers (P < 0.05). Smokers rated the intensity of all taste solutions lower than the nonsmokers.
Conclusion:
Frequent tobacco use impacts oral health, often unknown to the users. This study found altered perception of bitter taste in tobacco users. However, salivary pH and SFR showed minimal variation.
Keywords: pH, saliva, salivary flow rate, smokeless tobacco, taste perception, tobacco
INTRODUCTION
Smoking and smokeless tobacco use are prevalent throughout the globe, including in India. Both bidi and smokeless tobacco products, such as gutka and pan masala, contain numerous hazardous constituents, many of which are known carcinogens and have negative effects on oral health.[1,2] With comparison to the common misconception, perception and tobacco use alters its chemical composition, diminishing taste sensitivity.[2] The oral epithelium, glandular structure, taste buds and taste receptor cells are harmed by tobacco products.[3,4] These structural alterations can affect taste perception, eating patterns and nutritional status, potentially exacerbating the dangers of tobacco use.[5] The purpose of this study was to evaluate the effects of tobacco use on salivary flow rate, pH and taste perception to provide information for educating and motivating individuals to cease smoking. Smokeless tobacco has been proven to be equally harmful.[3] Saliva serves a vital role in maintaining oral health, including protecting the mucosa, aiding digestion, maintaining the pH balance and protecting the oral cavity.[6,7,8] Changes in saliva can contribute to oral and dental diseases, with a decrease in salivary flow rate (SFR) being linked to dental caries and periodontal disease.[8]
MATERIALS AND METHODS
A comparative study was conducted in which collection of saliva sample was carried out in late morning: an hour after breakfast. Ethical clearance was taken before start of the study. The subjects were instructed to clear the mouth by swallowing the residual saliva and to rinse with distilled water. To evaluate salivary flow rate, a piece of paraffin wax was provided to the individual and were asked to chew the piece of paraffin wax for 30 seconds so as to stimulate salivary flow. Saliva was collected after every 30 seconds for a total period of 5 minutes. The stimulated saliva was collected in a calibrated tube. The total quantity of saliva in ml was divided by 5 which gave measurement of salivary flow in ml per minute. Salivary pH measurement was carried out electrometrically using a digital pH meter.
Gustatory function was evaluated based on assessing the taste threshold by application of different taste solution on the patients tongue and by asking the patient to identify the type of tastes. To check different taste perception i.e. sweet, salty, sour and bitter taste, solutions of sucrose, sodium chloride, citric acid and quinine hydrochloride solution in five concentrations were used. For the study five concentration levels (in ½ log steps) of sucrose (0.01 mol/L – 1 mol/L), sodium chloride (0.01 mol/L – 1.0 mol/L), citric acid (0.32 mmol/L – 0.032 mol/L) and quinine hydrochloride (0.01 mmol/L – 1.0 mmol/L) were prepared.[7]
Patients were asked to taste solutions in ascending order of their concentration. The intensity threshold of taste perception of each solution was determined by scoring the lowest concentration as ‘5’ and the highest concentration as ‘1’. The concentration at which the patient was able to identify the taste was recorded, and the results were subjected to statistical analysis.
Statistical analysis
The values obtained were entered in Microsoft Excel using SPSS 20.0 software and were expressed as mean and standard deviation and calculated using one-way analysis of variance (ANOVA). To compare taste identification time in study and control groups, the unpaired t-test was done. P <0.05 indicated significant association at 5% level of significance.
RESULTS
The study included 60 individuals, 20 had habit of tobacco chewing and formed Group A, 20 had habit of smoking tobacco and formed Group B, and 20 did not have any habits and were part of control group (Group C). Salivary flow rate (SFR), pH and taste perception were evaluated.
On comparing salivary pH between tobacco chewers (Group A) and control group (Group C), it was observed that there was not much difference in salivary pH between the groups. The mean value of Group A (Tobacco chewers) of Salivary pH was calculated as 7.59 with 0.70 SD. For the control group (Group C), the mean value was obtained as 7.42 with 0.96 standard deviation. The independent t-test was applied, and the result was nonsignificant [Table 1].
Table 1.
Comparison of salivary pH and SFR between Group A and Group C
| Groups | Mean | Std. Deviation | t | P | |
|---|---|---|---|---|---|
| Salivary pH | Group A | 7.59 | 0.70 | 0.641 | 0.525NS |
| Control Group (Group C) | 7.42 | 0.96 | |||
| Salivary Flow rate | Group A | 1.75 | 0.71 | 1.15 | 0.258NS |
| Control Group (Group C) | 1.51 | 0.60 |
NS=Not significant
Similarly, when SFR was evaluated, it was observed that the mean value for SFR of Group A was 1.75 with 0.71 SD, and for the control group, it was 1.51 with 0.60 SD. The t-test (independent) was applied, and the result was nonsignificant [Table 1].
On comparing salivary pH between tobacco smokers (Group B) and control group (Group C), it was observed that the mean value of Group B (Tobacco smokers) of salivary pH was calculated as 7.69 with 1.00 SD. For the control group (Group C), the mean value was obtained as 7.42 with 0.96 standard deviation. The independent t-test was applied, and the result was nonsignificant [Table 2].
Table 2.
Comparison of salivary pH and SFR between Group B and Group C
| Groups | Mean | Std. Deviation | t | p | |
|---|---|---|---|---|---|
| Salivary pH | Group B | 7.69 | 1.00 | 0.892 | 0.378NS |
| Group C (Control Group) | 7.42 | 0.96 | |||
| Salivary Flow rate | Group B | 1.70 | 0.81 | 0.844 | 0.404NS |
| Group C (Control Group) | 1.51 | 0.60 |
NS=Not significant
Similarly, when SFR was evaluated, it was observed that the mean value of Group B was 1.70 with 0.81 SD, and for the control group, it was 1.51 mean value with 0.60 SD. The Student t-test (independent) was applied, and the result was not significant [Table 2].
On comparison of mean salivary pH and salivary flow rate amongst all the groups (A, B, C), it was observed that salivary pH and salivary flow were marginally increased in smokers and in chewers as compared to the control group. The average value was calculated as 7.59 for Group A, 7.69 for Group B, and 7.42 for the control group. The ANOVA test was applied, and F-calculated value was obtained as 0.484, and the result was nonsignificant [Table 3].
Table 3.
Comparison of salivary pH and SFR in different groups
| Groups | Mean | Std. Deviation | F | P | |
|---|---|---|---|---|---|
| Salivary pH | Group A | 7.59 | 0.70 | 0.484 | 0.619NS |
| Group B | 7.69 | 1.00 | |||
| Control Group | 7.42 | 0.96 | |||
| Salivary flow rate | Group A | 1.75 | 0.71 | 0.628 | 0.537NS |
| Group B | 1.70 | 0.81 | |||
| Control Group | 1.51 | 0.60 |
NS=Not significant
Similarly, for the flow rate, the average value for all three groups was almost same. The ANOVA test was applied, and F-value was calculated as 0.628, and the results were nonsignificant [Table 3].
Gustatory function/taste perception was evaluated based on assessing the taste threshold for sweet, salty sour and bitter taste. To evaluate this sucrose, sodium chloride, citric acid and quinine hydrochloride solution in five concentrations were used and subjects in all groups were exposed to the solutions in ascending order of their concentration.
It was observed that the taste perception for sweet (sucrose) in Group A (tobacco chewers) and Group B (smokers) was almost similar to that of Group C (control group). Maximum subjects responded to sucrose solution at 10% concentration. The Chi-square test was applied, and the result was not significant at 0.05 level of significance [Table 4].
Table 4.
Intensity of taste of perception for sucrose
| Sucrose | Group A | Group B | Group C (control group) | Chi-square Value | P |
|---|---|---|---|---|---|
| 1 | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 6.84 | 0.554NS |
| 2 | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | ||
| 3 | 0 (0.0%) | 2 (10.0%) | 0 (0.0%) | ||
| 4 | 3 (15.0%) | 0 (0.0%) | 2 (10.0%) | ||
| 5 | 17 (85.0%) | 18 (90.0%) | 18 (90.0%) |
NS=Not significant
On evaluation of perception salty taste (sodium chloride), it was observed that the taste perception for salty taste (sodium chloride) in Group A (tobacco chewers) was almost similar to that of Group C (control group). Maximum subjects responded to 10% solution. In case of Group B (tobacco smokers), 60% of subjects responded to solution at 10% concentration, 25% responded at 25% concentration, 5% responded at 50% concentration and 10% responded at 75% concentration. The Chi-square test was applied, and the result was not significant at 0.05 level of significance [Table 5].
Table 5.
Intensity of taste of perception for sodium chloride
| NACL | Group A | Group B | Control group | Chi-square Value | P |
|---|---|---|---|---|---|
| 1 | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 9.5 | 0.3019NS |
| 2 | 0 (0.0%) | 2 (10.0%) | 0 (0.0%) | ||
| 3 | 0 (0.0%) | 1 (5.0%) | 0 (0.0%) | ||
| 4 | 2 (10.0%) | 5 (25.0%) | 2 (10.0%) | ||
| 5 | 18 (90.0%) | 12 (60.0%) | 18 (90.0%) |
NS=Not significant
Some variations in taste perception for sour taste (citric acid) were observed amongst Group A, Group B and control group (Group C). In Group A (tobacco chewers), 70% of subjects responded at 10% concentration, 10% responded at 25% concentration and 20% responded at 50% concentration. In tobacco smokers (Group B), 55% of subjects responded at 10% concentration, 25% responded at 25% concentration, 15% responded at 50% concentration and 5% responded at 75% concentration. The results were compared with the control group. The Chi-square test was applied, and the result was not significant at 0.05 level of significance [Table 6].
Table 6.
Percentage of intensity of citric acid taste of perception
| Citric Acid | Group A | Group B | Control group | Chi-square Value | P |
|---|---|---|---|---|---|
| 1 | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 9.44 | 0.3065NS |
| 2 | 0 (0.0%) | 1 (5.0%) | 0 (0.0%) | ||
| 3 | 4 (20.0%) | 3 (15.0%) | 0 (0.0%) | ||
| 4 | 2 (10.0%) | 5 (25.0%) | 2 (10.0%) | ||
| 5 | 14 (70.0%) | 11 (55.0%) | 18 (90.0%) |
NS=Not significant
A decreased perception for bitter taste was observed in tobacco chewers and tobacco smokers. On evaluation of bitter taste perception (quinine hydrochloride) in Group A (tobacco chewers), 35% of subjects responded at 10% concentration, 45% responded at 25% concentration, 15% responded at 50% concentration and 5% responded at 75% concentration. In tobacco smokers (Group B), 20% of subjects responded at 10% concentration, 35% responded at 25% concentration, 20% responded at 50% concentration and 25% responded at 75% concentration. The results were compared with the control group, and the results were statistically significant [Table 7].
Table 7.
Intensity of taste perception for quinine hydrochloride
| Quinine | Group A | Group B | Control group | Chi-Square Value | P |
|---|---|---|---|---|---|
| 1 | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 17.67 | 0.0238* |
| 2 | 1 (5.0%) | 5 (25.0%) | 0 (0.0%) | ||
| 3 | 3 (15.0%) | 4 (20.0%) | 0 (0.0%) | ||
| 4 | 9 (45.0%) | 7 (35.0%) | 6 (30.0%) | ||
| 5 | 7 (35.0%) | 4 (20.0%) | 14 (70.0%) |
*Significant at 0.05 level of significance
DISCUSSION
Saliva performs multiple functions. It is involved in phonation, in protecting, and lubricating the oral cavity and plays an important role in taste perception.[9,10] Saliva maintains optimal oral health. Multiple factors like nutritional status, use of certain drugs and certain metabolic conditions can bring about a change in various salivary parameters like salivary pH salivary flow rate (SFR) and perception of various taste sensations.[10] Alterations in salivary components maybe associated with oral diseases.
In India, tobacco is consumed in various forms. The majority of tobacco is used to smoke cigarettes, bidis or other smokeless product. Tobacco is harmful in any form and can affect different organs in body.[11] Smoking forms have been associated with cancers of various organs of body. Smokeless form has seen to be associated with, an increased risk for preeclampsia, decreased birth weight and a small increase in CVS problems.[12,13] The harmful ingredients of tobacco diffuse in saliva and reach structures of oral cavity. This can then bring about certain functional and structural changes. This could further have an impact on salivary flow rate, pH and taste perception.
The composition and flow rate of saliva influences the salivary function. Optimum pH and SFR is important in maintaining good oral health. In the present study, when salivary pH was assessed amongst the subjects with habits, it was observed that the values of salivary pH in chewers, smokers and control group did not show much variation. Al–Weheb et al.[14] who had carried out a study to see the effect of smoking on lactobacilli count, caries and salivary pH and SFR, have stated that tobacco smoking affects dental caries but does not have an effect on salivary pH and SFR. Some studies have reported a decrease in salivary pH in smokers as compared to nonsmokers.[15,16] In the present study, the mean salivary flow rate was marginally increased in tobacco chewers and smokers as compared to the control group. Shubha et al.[17] observed a decrease in SFR amongst tobacco users. Rehan et al.[8] did not find a significant difference in salivary flow rate amongst tobacco chewers, smokers and control group in their study. However, they have observed a marginal increase in SFR during the initial use of tobacco.
In our study, gustatory function was evaluated based on assessing the taste threshold by application of different taste solution on the patients tongue and by asking the patient to identify the type of tastes.[7,13] It was observed that sweet taste was perceived better as compared to salty, sour and bitter taste. Some variations in taste perception for salty and bitter taste were observed in tobacco chewers and smokers, but these were not statistically significant. On comparing taste perception for bitter in subjects with chewing and smoking habit with the control group, subjects perceived the bitter taste at higher concentration of the solution which was statistically significant. Krut et al.[18] suggested that a long-term smoking is directly associated with decrease acuity for bitter taste perception.[18] They suggested that tobacco constituents that diffuse out in saliva could inhibit enzyme esterase in taste buds, which could alter the taste perception. Khan et al.[19] suggested that alterations in taste sensitivity and a higher electrogustometric threshold could be associated with reduction in number and in alterations in size, shape and vascular supply of the fungiform papillae. The various by products released on tobacco consumption lead to hyperkeratosis of papillae and alter the taste identification time[4] Ferragut JM et al.[2] observed that constituents of tobacco affects the salivary glands and leads to some structural changes within the gland. They observed an intense inflammatory response and an increase in collagen in the connective tissue. Such alterations in acinar structure could affect the functioning of salivary glands[2] and could further influence the salivary parameters and taste perception.
CONCLUSION
The study found altered taste perception in tobacco users, with a significant association between bitter taste perception and tobacco use. However, salivary pH and SFR showed minimal alterations. The study is simple and can be easily carried out. A study with larger sample size is suggested for a more comprehensive understanding.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity.
Conflicts of interest
There are no conflicts of interest.
Acknowledgement
We acknowledge the support provided by Department of Biochemistry, FMHS, SGTU, Gurugram. We acknowledge the support of ICMR-STS program under whom the study was carried out.
Funding Statement
Nil.
REFERENCES
- 1.Matsuo R. Role of saliva in the maintenance of taste sensitivity. Crit Rev Oral Biol Med. 2000;11:216–29. doi: 10.1177/10454411000110020501. [DOI] [PubMed] [Google Scholar]
- 2.Ferragut JM, Cunha M, Carvalho C, Isayama R, Caldeira E. Epithelial–stromal interactions in salivary glands of rats exposed to chronic passive smoking. Arch Oral Biol. 2011;56:580–7. doi: 10.1016/j.archoralbio.2010.11.017. [DOI] [PubMed] [Google Scholar]
- 3.Khoso SM, Khoso PA, Qazi N, Khoso MH, Jatoi AS, Kaka U. Histological features of parotid gland of albino rats exposed to smokeless tobacco. J Northeast Agric Univ. 2016;23:54–60. [Google Scholar]
- 4.Kale YS, Vibhute N, Belgaumi U, Kadashetti V, Bommanavar S, Kamate W. Effect of using tobacco on taste perception. J Family Med Prim Care. 2019;8:2699–702. doi: 10.4103/jfmpc.jfmpc_457_19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Dangore-Khasbage SB, Degwekar SS, Bhowate RR, Motwani MB, Indurkar AD, Lohe VK, Babar VY. Comparative evaluation of gustatory function between postmenopausal women and age-matched men. Oral Dis. 2010;16:469–75. doi: 10.1111/j.1601-0825.2010.01658.x. [DOI] [PubMed] [Google Scholar]
- 6.Kanwar A, Sah K, Grover N, Singh R. Long term effect of tobacco on resting whole mouth salivary flow rate and pH: An institutional based comparative study. Eur J Gen Dent. 2013;2:296–9. [Google Scholar]
- 7.Saluja P, Shetty V, Dave A, Arora M, Hans V, Madan A. Comparative evaluation of the effect of menstruation, pregnancy and menopause on salivary flow rate, pH and gustatory function. J Clin Diagn Res. 2014;8:ZC81–5. doi: 10.7860/JCDR/2014/9935.5071. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Rehan F, Khan RS, Khurshid Z, Memon MS, Naqvi S, Zafar MS. Analysis of resting mouth salivary flow rate and salivary pH of tobacco chewers and smokers. J Pak Dent Assoc. 2016;25:158–63. [Google Scholar]
- 9.Berube L, Duffy VB, Hayes JE, Hoffman HJ, Rawal S. Associations between chronic cigarette smoking and taste function: Results from the, 2013-2014 national health and nutrition examination survey. Physiol Behav. 2021;240:113554. doi: 10.1016/j.physbeh.2021.113554. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Chao AM, Zhou Y, Franks AT, Brooks BE, Joseph PV. Associations of taste perception with tobacco smoking, marijuana use, and weight status in the National Health and Nutrition Examination Survey. Chem Senses. 2021;46:bjab017. doi: 10.1093/chemse/bjab017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Hiss LS, Carneiro ACDM, Rosa RC, Micheletti AMR, Volpon JB, Crema VO. Effects of tobacco smoke inhalation on the morphology and cell proliferation rate in Wistar rats submandibular glands. Res Soc Dev. 2021;8:e28510817327. [Google Scholar]
- 12.Harini TC Anbu Ila, Nagarajappa AK, Kolte DR, Gunturu S. Comparative evaluation of alteration in taste perception among Gutkha chewers with and without OSMF and healthy subjects: A prospective case-control study. J Oral Maxillofac Pathol. 2022;26:208–17. doi: 10.4103/jomfp.jomfp_38_21. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Delilbasi C, Cehiz T, Akal UK, Yilmaz T. Evaluation of gustatory function in postmenopausal women. Br Dent J. 2003;194:447–9. doi: 10.1038/sj.bdj.4810030. [DOI] [PubMed] [Google Scholar]
- 14.Al-Weheb AM. Smoking and its relation to caries experience and lactobacilli count. J Coll Dentistry. 2005;17:92–5. [Google Scholar]
- 15.Challap ID, Lafta FM, Al-Rekabi A-ANG, Ahmed F, Qasim R. Investigation the impact of smoking on salivary pH and the reasons behind smoking. J Phys Conf Ser. 2019;1294:062069. doi: 10.1088/1742-6596/1294/6/062069. [Google Scholar]
- 16.Kayani UZ, Mansoor HB, Asif H, Nadeem N, Aslam A, Kayani HZ. Comparison of salivary pH among smokers and non-smokers by keeping DMFT at unity. J Bahria Uni Med Dental Coll. 2020;10:224–7. [Google Scholar]
- 17.Shubha G, Fasalkar SS, N PB, Patrick S, Raghavan SA, Gurushanth K. Assessment of salivary flow rate and salivary pH in subjects with smoking and smokeless form of tobacco habits. J Med Radiol Pathol Surg. 2018;5:11–5. [Google Scholar]
- 18.Krut LH, Perrin MJ, Bronte-Stewart B. Taste perception in smokers and non-smokers. Br Med J. 1961;1:384–7. doi: 10.1136/bmj.1.5223.384. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Khan AM, Narayanan VS, Puttabuddi JH, Chengappa R, Ambaldhage VK, Naik P, et al. Comparison of taste threshold in smokers and non-smokers using electrogustometry and fungiform papillae count: A case control study. J Clin Diagn Res. 2016;10:ZC101–5. doi: 10.7860/JCDR/2016/14478.7835. [DOI] [PMC free article] [PubMed] [Google Scholar]