|Year : 2017 | Volume
| Issue : 3 | Page : 254-259
Effect of three commercially available chewing gums on salivary flow rate and pH in caries-active and caries-free children: An in vivo study
Usha Kiran Vantipalli, Sai Sankar Jogendra Avula, Sridevi Enuganti, Sujatha Bandi, Pranitha Kakarla, Raja Vardhan Kuravadi
Department of Pedodontics and Preventive Dentistry, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh, India
|Date of Web Publication||31-Jul-2017|
Sai Sankar Jogendra Avula
Department of Pedodontics and Preventive Dentistry, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background and Aim: Adequate salivary flow is an important requisite in the maintenance of oral health. Salivary flow increases in response to both gustatory (taste) and mechanical (chewing) stimuli. Hence, the aim of the present study was to know the efficacy of commercially available chewing gums (sugar free and sugared) on salivary flow rate (SFR) and pH in caries-active and caries-free children. Materials and Methods: One hundred school children aged between 10 and 12 years were divided into two groups on the basis of their caries status into caries free and caries active. Unstimulated saliva was collected before start of the study. Both groups were subjected to three commercially available chewing gums (2 sugar free, 1 sugared) on consecutive days, and saliva was collected at intervals of 2 min (T2), 10 min (T10), and 30 min (T30). The pH and flow rate of saliva samples were measured before and specified time intervals after gum chewing. Results: In both the groups, gum chewing increased the SFR, significantly at T2, and gradually declined at T30 which was significantly higher than baseline values. The pH raised significantly at T2 and gradually declined at T30 which was significantly higher than baseline values with sugar-free gums, but with sugared gums, the pH raised slightly at T2 and dropped significantly at T30. However, no statistically significant differences in pH and flow rate were noticed in both the groups. Conclusion: Chewing of sugar-free gums in both caries-active and caries-free children may aid in reducing the incidence of dental caries.
Keywords: Chewing gum, pH, saliva, salivary flow rate
|How to cite this article:|
Vantipalli UK, Avula SS, Enuganti S, Bandi S, Kakarla P, Kuravadi RV. Effect of three commercially available chewing gums on salivary flow rate and pH in caries-active and caries-free children: An in vivo study. J Indian Soc Pedod Prev Dent 2017;35:254-9
|How to cite this URL:|
Vantipalli UK, Avula SS, Enuganti S, Bandi S, Kakarla P, Kuravadi RV. Effect of three commercially available chewing gums on salivary flow rate and pH in caries-active and caries-free children: An in vivo study. J Indian Soc Pedod Prev Dent [serial online] 2017 [cited 2020 Sep 23];35:254-9. Available from: http://www.jisppd.com/text.asp?2017/35/3/254/211849
| Introduction|| |
Dental caries is a complex and dynamic process where a multitude of factors influence and initiate the progression of disease. One prime factor which has immense capacity to modulate the initiation and progression of dental caries is saliva. Alterations in the physicochemical properties of saliva such as altered composition decreased salivary flow rate (SFR), pH, and buffering capacity favors the caries process. This is clearly evident in xerostomic patients. The prime sign associated with xerostomia is drastic increase in incidence of dental decay; other symptoms include cheilosis, glossopyrosis, glossodynia, thirst, dysphagia, dysphonia and masticatory inadequacy; hence, it is important to have an adequate salivary flow.
On the other hand, flushing and neutralizing effects of saliva help in haltering the caries process as well as maintain good oral health. This effect is commonly referred as “salivary clearance” or “oral clearance capacity.” The average unstimulated salivary flow range between 0.26 and 0.39 ml/min in general population.
In addition to regular flow, enhanced salivary flow has been observed with gustatory (taste), mechanical (chewing), olfactory, and visual stimulation. Among all the salivary stimulants, gum chewing gained popularity as it is economical, easy available, and its ability to stimulate flow by providing both gustatory and mechanical stimulation, thus leading to hastened clearance of fermentable carbohydrates. Studies have shown that salivary stimulation caused by gum chewing is psychologically more acceptable for the patient and also claimed to have cariostatic (sugar-free gums) effects.
Thus, the aim of the present study was to test the above-mentioned hypothesis by measuring SFR and pH before and after chewing sugared and sugar-free chewing gum in caries-free and caries-active children.
| Materials and Methods|| |
A total of 4000 children without gender differentiation aged between 10 and 12 years, attending various schools in Guntur district, Andhra Pradesh, were screened during January 2013–September 2014. Out of which, 510 children (246 caries-free, 264 caries-active) who were permanent residents of Guntur town and consuming water supplied only from the centralized water system and free from any local or systemic diseases were included in this study. However, physically or mentally compromised children and children undergoing orthodontic treatment were excluded from this study. Caries status was assessed according to the WHO criteria (1997) – caries-active children (decayed, missing, filled surface [DMFS] ≥5) and caries-free children (DMFS = 0).
On explaining the study protocol, 407 patients (200 caries-free, 207 caries-active) had given their willingness to participate in the study. However, for ease in statistical analysis, only 200 caries-free and 200 caries-active patients were considered and designated as Groups A and B, respectively. Before starting up the study, Institutional Ethical Committee clearance was acquired and an informed written consent was obtained from all parents/guardians. Further, these children were referred to the Department of Pedodontics and Preventive Dentistry, where the study process was carried out. In the first visit, all study samples were subjected to oral prophylaxis and were instructed to refrain from eating, drinking, or other oral hygiene procedures like brushing with fluoridated toothpaste, at least 1 h before salivary sample collection. In the subsequent visits, each child in both the groups were subjected to three commercially available chewing gums of same flavor (spearmint) weighing 1.1 g/pellet, of which two are sugar-free and one sugared chewing gum for three consecutive days [Figure 1] (Group I – Orbit sugar-free chewing gum [Wrigley India Pvt. Ltd, India], Group II – Happydent complete sugar-free chewing gum [Perfetti Van Melle, Italy], and Group III – Spearmint sugared chewing gum [Wrigley India Pvt. Ltd, India]).
To avoid the possible confounding effects of circadian rhythms in the SFR, the study was performed in the morning hours, from 9 to 12 am, all through the study period.
The saliva sample collection was done based on guidelines given by the University of Southern California School of Dentistry. Spitting method was used for collection of saliva samples. Participants were instructed to swallow the residual saliva present in the mouth to begin a collection trial; further, they were asked to expectorate the saliva in a sterile graduated test tube [Figure 2]a.
|Figure 2: (a) Salivary sample collection. (b) Recording salivary flow rate. (c) Recording salivary pH|
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On day one, unstimulated saliva was collected for 5 min for all the participants in Groups A and B before chewing any gum. Further, these participants were provided with single pellet of Group I chewing gum, and stimulated saliva was collected at three time intervals of 2–4 min (T2), 10 min (T10), and 30 min (T30), respectively. During these collection periods, the children were instructed not to swallow the saliva. The salivary pH and flow rate of all the samples were measured before and after gum chewing. Same methodology was followed for other 2 consecutive days using Group II and III chewing gums.
The flow rate of the saliva was calculated by measuring the volume of saliva collected in the graduated sterile test tube and converted to flow rate per minute [Figure 2]b. The pH of the saliva samples was measured immediately after collection to minimize any time-based pH changes [Figure 2]c using a calibrated digital pH meter (DPH – 500, Global Electronics Pvt. Ltd, Hyderabad, India) with accuracy of ±0.01.
For statistical data analysis, the stimulated flow rate and pH data were compared with the corresponding data for unstimulated saliva by one-way analysis of variance test. Intergroup comparison of stimulated salivary pH and flow rate within different time periods was done by unpaired Student's t-test.
| Results|| |
The total study samples were divided into caries-free (Group A) and caries-active (Group B) groups. Each individual in both the groups were subjected to all the three selected chewing gums (Group I - Orbit [sugar free], Group II - Happydent complete [sugar free], and Group III - Spearmint [sugared] chewing gum). T0 represents unstimulated saliva, T2 represents time interval of 2 min, T10 represents 10 min, and T30 represents 30 min time interval after initiation of gum chewing, where stimulated saliva was collected for the calibration of pH and SFR.
In Groups A and B, chewing of sugar-free gum (Groups I and II) had led to significant rise in the salivary pH from T0 to T2 and gradually tapered to T30. However, the pH at T30 was significantly higher than at T0. Conversely, chewing sugared gum (Group III) had led to slight rise in pH from T0 to T2 followed by significant drop at T30, and this drop in pH was far below the pH value at T0[Table l].
|Table 1: Mean intragroup comparison of salivary pH in caries-free and caries-active children at different time intervals|
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When SFR was considered both Groups A and B, individuals demonstrated statistically significant rise in the SFR from T0 to T2 followed by gradual tapering to T30 but this SFR at T30 was significantly higher than baseline values (T0) with all the Groups I, II, and III [Table 2].
|Table 2: Mean intragroup comparison of salivary flow rate in caries-free and caries-active children at different time intervals|
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Intragroup comparison elicited no statistical significant difference in pH within different time intervals tested between Groups I and II. However, significant difference was observed between Groups I and III and II and III in both the Groups A and B [Table 3].
[Table 4] represents the intragroup comparison of SFR in both caries-active and caries-free children, where there was no statistically significant difference in SFR at specified time intervals with any of the chewing gum types.
|Table 4: Inter subgroup comparison of salivary flow rate in caries-active group|
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Intergroup comparison between Groups A and B with respect to the both tested parameters (pH and SFR), there was no statistically significant difference in the values at measured time intervals [Table 5].
| Discussion|| |
Chewing gums are made of natural or synthetic materials. The basic composition of chewing gum consists of gum base; to these small amounts of preservatives, sweetening, flavoring, and aromatic agents will be added. Basically, two types of sweeteners present in the chewing gums; carbohydrates (usually sucrose) and noncarbohydrate sweeteners. Polyols are low-caloric noncarbohydrate sweeteners predominantly used in chewing gum. Frequently used polyols are sorbitol which is hexatol, and xylitol is a pentatol. Mäkinen et al. hypothesized that pentatols are more effective than hexatols in preventing caries. Hence, chewing gums containing xylitol and sorbitol as major component were selected for the study along with a sugared chewing gum to test the variation in selected salivary parameters.
In both Groups A and B children, with all the three selected chewing gums (Groups I, II, and III), a significant increase in stimulated SFR was observed at T2, followed by significant decline at T10 and T30. However, this stimulated SFR remained significantly higher when compared to flow rate at T0. Similar results were reported by Polland et al. and Dawes and Kubieniec. The initial increase in flow rate is probably due to gustatory stimulus induced by the chewing gums; further, continuous chewing of gums led to loss of flavor, softening, and reduction in the gum size that minimizes the stimulation of periodontal mechanoreceptors, which may in turn contribute to the decrease in flow rate from T2 to T30 but the act of chewing was responsible for elevated SFR at T30 compared to T0.,,, Whatever may be the type of chewing gum (Groups I, II, and III) used, there was no statistically significant difference in regard to the rise in SFR, and this finding is in consistent with the findings of Dawes and Dong, Aguirre-Zero et al., and Bots et al. Dong et al. states that the flow rate was independent of chewing frequency within a range of 35–130 chewing maneuvers per minute. However, studies by Aguirre-Zero et al., Machiulskiene et al., and Ribelles Llop et al. have stated that the act of chewing is essential to increase SFR, which is independent of the type of sweetener present in the chewing gum.
When salivary pH was considered, the Group I and II chewing gums caused significant rise in salivary pH at T2, followed by progressive decline at T10 and T30. However, this remained significantly above the unstimulated salivary pH (T0) in both the Groups A and B. This findings of the study coincided with results obtained by Dawes and Kubieniec, Polland et al., and Markovic et al. The increase in salivary pH on stimulation was due to increase in bicarbonate concentration, which will be proportional to the flow rate. In contrast with Group III chewing gum, it was observed that slight increase in pH from T0 to T2 followed by significant drop at T30 which was well below the baseline value (T0). The study conducted by Imfeld  showed low plaque pH values during and after the chewing of sucrose-containing chewing gum in spite of the masticatory stimulation of saliva. Dawson and Dong reported that when sucrose-containing and sugar-free gums were chewed, the flow rate was approximately equal, but the saliva elicited by sucrose-containing gum contained less bicarbonate and suggested that it could be due to the reaction of bicarbonate with acid produced by bacterial metabolism of sugar, resulting in drop of salivary pH. However, observations by Karami-Nogourani et al. showed that the presence of citric and maleic acids in fruit-flavored gums (strawberry and apple) could be responsible for less pH when compared to nonfruit-flavored chewing gums (spearmint and cinnamon).
Intergroup comparison of Group I and II showed no statistically significant difference in salivary pH at above-mentioned time intervals. These findings are homogeneous with the study conducted by Bots et al. However, the comparison of Group III with Groups I and II showed a statistically significant difference in the salivary pH because chewing of sugared gum lead to decline in salivary pH. Similar results were elicited by Kumar et al. who showed that sugar-free chewing gums are more beneficial in preventing dental caries than sugared chewing gum by increasing salivary and plaque pH. In contrast, Manning and Edgar found no statistically significant differences in pH recovery after eating meals or snacks followed by a chewing gum sweetened with sugar or other sweeteners for 20 min. However, a study by Park et al. found that chewing sugar-free chewing gum for 20 min was more effective in producing recovery of pH levels than sugared chewing gum. In contrary, the present study showed marked increase in salivary pH after chewing sugar-free gum which indicates that they not only help to elevate the lowered pH of saliva after any meal but also maintain the normal pH of saliva at any given period.
Within the constraints of this study, it was depicted that with the use of sugar-free (xylitol/sorbitol) chewing gums, there was a linear increase in SFR and pH in both caries-free and caries-active children which may lead to reduction in caries activity in contrast to the use of sugared chewing gums.
Till now, in the literature, the information available was sparse regarding the variation in SFR and pH in caries-free and caries-active children. In the present study from the obtained values, it was evident that the pattern of salivary changes in terms of SFR and pH after gum chewing was similar in both the groups. However, though this was not statistically significant, the basic SFR and pH were comparatively less in caries-active children, thus giving an insight into inherent propensity of the host to get affected by caries irrespective of caries activity. Further, clinical trials with well-defined microbial counts in caries-free and caries-active children with specific salivary parameters have to be designed to know the effect of inherent salivary properties and use of these sought of salivary stimulants influencing incidence and progression of dental caries.
| Conclusion|| |
- There is no significant difference in basic salivary pH and flow rate between caries-active and caries-free children
- Irrespective of caries experience chewing sugar-free gum had led to increase in salivary pH and SFR but chewing sugared gum caused a drastic decrease in salivary pH
- From this study, this is evident that though the caries experience is dependent on both the above-mentioned salivary factors, most frequently involved factor is salivary pH. Hence, chewing sugar-free gum can be recommended both in caries-free and caries-active children to keep the pH balanced as it provides protection against dental caries.
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, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]