THE IMMEDIATE TERM EFFECT OF CHEWING MESWAK(SAL VADORA PERSICA) ON FLOW RATE AND PH OF WHOLE SALIVAN.M. Hairuddin, R.A. JaW. The immediate term effectof chewing meswak (Salvadora persica) on flow rateand pH of whole saliva. Annal Dent Univ Malaya 2000;7: 6-10.

ABSTRACT

The objective of this study was to determine the effectchewing of two differently sized commercially availablemeswak might have on flow rate and pH of wholesaliva. Twenty subjects participated in this study. Theywere distributed into two groups (A and B). Subjectsin both groups A and B were asked to first chew oneither a sized #1 or #2 cotton roll followed by thechewing of an equivalent sized piece of meswak(approximately 5 mm. and 10 mm. diameter)respectively.

For subjects in group A, no differences in meanflow rate was seen after both the chewing regimes. Ingroup B however, the increase in mean flow rate afterthe chewing of meswak compared to cotton roll wasstatistically significant at p < 0.05. Statisticallysignificant lower values for pH were registered after thechewing of meswak compared to cotton roll in bothgroups A and B at p<0.05 and p<O.OI respectively.

Results of this study suggest that plants used aschewing sticks may have the potential of both increasingthe flow rate and reducing the pH of saliva. Furtherstudies have to be carried out to ascertain the therapeuticbenefits of using meswak as an anti-plaque agent.

Key words: saliva, xerostomia, flow rate, pH.

INTRODUCTION

The importance of saliva in the prevention of variousoral diseases is substantiated by the clinical observationthat rampant caries, gingivitis and soreness of the oralmucosa characterize xerostomia (I). The treatment ofxerostomia is designed to either eliminate the cause orcauses of these conditions or if this is not possible toalleviate the patients symptoms and clinical signs.Masticatory stimuli, chemical stimuli and drugs havebeen used to promote salivation. Patients should beencouraged to consume foods which require mastication.Chewing gum is an effective sialogogue however,because of the increased risk of dental caries only thesugarless variety of gum should be used. One studyhas shown that the frequent chewing of sugarless gumfor a period of two weeks increased the output ofstimulated parotid saliva and increased the pH andbuffer capacity of whole and parotid saliva (2).

The use of chewing sticks to enhance salivarysecretion in the management of xerostomia has not beenexplored. The most widely used chewing stick is the

Origina.l Article

N.M. Hairuddin1 and R.A. JaliF

IDepartment of Oral Biology and

2Department of Oral Pathology,Oral Medicine and PeriodontologyFaculty of DentistryUniversity of Malaya50603 Kuala LumpurMalaysia

Corresponding author - R.A. JaW

meswak which is obtained from the plant, Salvadorapersica that mainly grows in the Middle East (3,4).Like chewing gums, chewing sticks too may have ahydrodynamic pumping effect on plaque which mightnot be expected with other mechanical stimuli. Inaddition, chewing sticks may have a combinedmechanical and chemical stimuli. Products with ahydrodynamic effect might be superior tononhydrodynamic mechanical and chemical stimuli,although no data exist to support this hypothesis.

The objective of this study was to look atdifferences in the flow rate and pH of stimulated wholesaliva (SWS) after the chewing of two differently sizedcommercially available meswak (M) as opposed tochewing with an equivalent sized piece of inert materialwhich in this case was cotton roll (CR).

MATERIALS AND METHODS

20 dental students and dental auxiliaries (aged 19 to 47years old) volunteered to take part in this study. Sinceassessments were made only at the laboratory level,volunteers were accepted regardless of their age, oraland medical status. Before the start of the study allsubjects received verbal information about the objectiveof the study and gave informed consent by filling upthe forms provided to them. Participants were instructednot to consume any food and beverages two hours priorto saliva collection.

Cotton roll was chosen as an inert eliciting agentfor pre-meswak samples of stimulated whole saliva. Theuse of cotton roll (CR) is preferred over the use of eitherparaffin wax or corrugated rubber since the physicalproperty of meswak (M) as used in this study closelyresembled the physical property of the cotton roll notonly in its size but also in its shape. Like cotton rolltoo, the meswak loses its cylindrical shape a fewminutes after chewing turning into a rather flat pieceof chewing material.

The immediate term effect of chewing meswak (Salvadora persica) on now rate and pH of whole saliva 7

Group B, chewing of colton roll (size #2) followed bymeswak (10 mm diameter)

Group A, chewing of colton roll (size #1) followed bymeswak (5 mm diameter)

Group A, chewing of colton roll (size #1) followed bymeswak (5 mm diameter)

Table 2. Mean values and range for pH in stimulated whole salivaafter the chewing of cotton roll and meswak with standard

deviation in parentheses

t-test Sig. levels

1.11 (0.48) -0.121 P > 0.05

0.43 - 2.00

1.18(0.25) -2.314 P<0.05

0.89 - 1.60

Meswak t-test Sig. levelsMean (S.D.)

Meswak t-test Sig. levelsMean (S.D.)

MeswakMean (S.D.)

1.10 (0.47)

0.64 - 2.00

0.91 (0.20)

0.67 - 1.33

Cotton rollMean (S.D.)

Cotton rollMean (S.D.)

Cotton rollMean (S.D.)

Range

Range

Table 2 presents results pertaining to the range forpH in stimulated whole saliva together with thecorresponding mean and standard deviations for subjectsin both groups A and B. A decrease in mean pH wasobserved after the chewing of meswak compared tocotton roll. Analysis of contrasts carried out revealedthat the decrease in pH after the chewing of meswak inboth groups A and B were statistically significant atp<0.05 and p<O.OI respectively.

In order to explore relationships between flow ratesand pH, Pearson's correlation coefficients werecalculated and presented in table 3. No associationswere apparent between flow rates and pH values afterchewing with the sized #1, #2 cotton roll and 5 mm.

Subject

Subject

Table 1. Mean values and range for flow rate in stimulated wholesaliva after the chewing of cotton roll and meswak with standard

deviation in parentheses (ml/min)

Group B

Group A

Subject

RESULTS

Saliva collection took place between 11.00 am to12.00 pm, approximately two hours after the last intakeof food or beverages. All subjects first chewed cottonroll at a constant rate of approximately one chew persecond changing the chewing sides every 30 seconds fortwo minutes in order to achieve "maximal" stimulation.This saliva was then discarded and not used in theanalysis.

The twenty subjects were then divided into twogroups comprising of 10 subjects in group A and another10 in group B. Subjects in group A resumed the chewingaction specified earlier using a newly provided cottonroll (size #1) and the stimulated whole saliva collectedin the mouth was then gently transferred into agraduated tube at the end of every 30 seconds. Subjectsthen switched chewing from one side of the mouth tothe other every 30 seconds until approximately 4 ml ofstimulated whole saliva was collected. The time takento collect 4 m!. of stimulated whole saliva was recordedfor the purpose of calculating the flow rate accordingto the formula volume collected / time taken to collectthe volume of saliva. This whole procedure was thenrepeated with a piece of meswak (5 mm. diameter) usingthe specified chewing action until approximately 4 m!.of stimulated whole saliva was collected.

Using the same protocol, subjects in group Bstarted by chewing on sized #2 cotton roll after which4 m!. of stimulated whole saliva was collected. Subjectsthen commenced chewing on a 10 mm. diametermeswak until 4 m!. of stimulated whole saliva wascollected. The time taken to collect the saliva was againnoted. Immediately upon collection, the pH values ofthe samples were determined.

pH of stimulated whole saliva was determinedimmediately upon saliva collection via the use of aBeckman pH meter whilst flow rate of saliva wasdetermined by calculating the volume of saliva collected/time taken to collect the sample.

Statistical analysis was carried out using SPSS 8th

edition to determine mean values, standard deviationsand frequency distribution. In order to explorerelationships between flow rate and pH values ofstimulated whole saliva, Pearson's correlationcoefficients was used. Analysis of contrast through theuse of student's t-test was also carried out in order toseek out differences between the means.

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Group A 7.24 (0.19) 7.07 (0.28) 2.695 P < 0.05

Group B, chewing of colton roll (size #2) followed bymeswak (10 mm diameter)I

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11

Table 1 presents results pertaining to the range for flowrate in stimulated whole saliva together with thecorresponding mean and standard deviations for subjectsin both groups A and B. No difference in the mean valuefor flow rate was observed in group A after the twochewing regimes. In group B however, a substantialincrease in mean value for flow rate was observed afterthe chewing of the 10 mm. diameter meswak comparedto the sized 1i2 cotton roll. Analysis of contrasts carriedout reve'aled that the difference was statisticallysignificant at p < 0.05.

Range

Subject

Group B

Range

7.03 - 7.57

Cotton rollMean (S.D.)

7.40 (0.20)

7.05-7.13

6.71 - 7.58

Meswak t-test Sig. levelsMean (S.D.)

7.09 (0.26) 4.266 P < 0.01

6.73 - 7.52

8 Annals of Dentistry, University of Malaya. Vol. 72000

DISCUSSION

Table 3. Coefficients for correlation between flow rate and pH inwhole saliva after the chewing of cotton roll (CR) and meswak (M)

diameter meswak. However, a negative associationof r = - 0.637 was seen between flow rate and pHafter the chewing of the 10 mm. diameter meswak. Thisassociation was statistically significant at p < 0.05.

Xerostomia is the subjective complaint of oral dryness.The mucosa is dry and rough, bleeds easily and becomesreadily infected with large accumulations of plaque. Thetongue appears smooth and inflamed (5). At the sametime, the salivary pH and buffer capacity in thesepatients are frequently depressed. In these subjects, thewidely observed development of rapidly progressingrampant caries, often attacking unusual sites can beseen. Included among these are the lower anterior teeth,the cusps and cervical regions of the teeth. In theseareas, the teeth may have a white opaque appearancedue to demineralization. Cariogenic organisms such asStreptococcus mutans, Lactobacilli and Actinomycesviscosus become dominant, while Streptococcus sanguis,Streptococcus salivarius, Fusobacteria and Neisseriashow a decrease (6, 7).

Many commonly used medications predispose toxerostomia. However, the nature and severity of thedisease for which these drugs have been prescribed maypreclude their removal. The objective of symptomatictreatment of xerostomia is to increase the overallwetness of the oral tissues. The success of theseinterventions is dependent on the degree to which thesalivary glands are able to respond to various stimuli.

In patients with viable, residual salivary glandtissue, it may be possible to stimulate the flow of theirsaliva. Such patients are referred to as "responders".Where this is not possible, in "non-responders"treatment must be designed to provide moisture to theoral tissues by other means.

Although salivary secretion has been the subject ofseveral quantitative and qualitative investigations, theresults obtained have been contradictory. This lack ofagreement may be explained by differences in theexperimental design. The rate of secretion and the

chemical cOmpOSItlOn of saliva found in a giveninvestigation depend on the method of measurement, theduration of sampling, the hour of sampling, the intervalsince last meal, the age, sex and mental state of thedonor. In order to diminish the effect of some of thegeneral factors, the present investigation was performedwhere the method of collection, posture of the personstudied, time of last meal had been standardized as faras possible.

Circadian variations in some salivary componentshave previously been demonstrated in both men andexperimental animals. Dogon and co-workers (8)showed 24 hour variation in the secretions of bothchloride and thiocyanate. Ferguson and Fort (9)examined in detail the circadian variation in flow rateand concentrations of sodium, potassium, calcium,chloride, total and inorganic phosphate, nitrogen,protein and total carbohydrate in unstimulated humansubmandibular saliva and found changes inconcentrations of some salivary components due tocircadian variation. Henceforth, the effect of circadianvariation was also taken into consideration in the designof the experiment since circadian rhythm is not onlyknown to affect salivary composition but to some extent,flow rate as well (10,11).

The purpose of this study was to investigate theimmediate term effect of chewing two differently sizedcommercially available meswak on flow rate and pH.The result of this study seemed to indicate that the 10mm. diameter meswak is more effective in stimulatingsalivary flow when compared to either the 5 mmmeswak or the cotton roll.

Studies have shown that subjects with low cariestended to have higher mean flow rates of unstimulatedparotid saliva compared to those in the higher cariesgroup (5,12). The most comprehensive study wasconducted by Shannon and Terry (13) who measuredparotid flow rate without exogenous stimulation in 3,786healthy young adult males. In the group with 0 to 10DMFS there was a significantly higher flow rate(0.041mllmin) than in all the other subjects (0.037 mllmin) with DMFS from 10 to more than 50.

Any consideration of flow rates cannot be divorcedfrom that of pH and buffering. With an increase insecretion rate, there is an increase in both pH andbuffering capacity (16) and the increase in flow rate willtend to remove carbohydrate from the mouth. Continuedstimulation of saliva following a meal or snack, exampleby chewing sugar free gum raises plaque pH and thusreduces demineralization and favors demineralization.

In this study, with regards to pH, both sizes meswakhad the potential of decreasing the pH of stimulatedwhole saliva. This observation was also seen in anearlier study by Gazi et al 1992 (15). Although thedecrease in pH were statistically significant at p < 0.05for subjects in group A and at p < 0.01 for those ingroup B, the range of values registered after thechewing of meswak were still higher than the "criticalpH". It has been calculated that saliva remains saturateduntil the pH falls to about 5.85 - 5.20 i.e. the so called"critical pH" below which enamel dissolves (5).

0.421

-0.034

-0.637*

0.466

pH pH pH pHCR size #1 CR size #2 M 5 mm. M 10 mm.

Flow rateCR size #1

Flow rateCR size #2

Flow rateM 5 mm.

·p<O.05

Flow rateM 10 mm.

The immediate term effect of chewing meswak (Salvadora persica) on now rate and pH of whole saliva 9

When association were explored between flow rateand pH, a negative association was found in bothgroups of subjects after the chewing of meswak.However the association was only statisticallysignificant in group B at the p < 0.05. These findingscould be attributed to the chemical content of meswaksince meswak has been found to contain fluoride, silica,alkaloids, essential oils, resins, gum and atraquinones.These substances could have either directly or indirectlycontributed to the decrease in pH as seen in this study.Results of this study seemed to indicate that the thickermeswak (lOmm. diameter) contributed more towardsdecreasing the pH of saliva compared to the thinnermeswak.

A positive association was seen between salivaryflow rate and pH in this study after the chewing ofcotton roll. However, the positive association seen didnot reach levels of statistical significance. The positiveassociation seen between flow rate and pH after thechewing of cotton roll is in agreement with earlierinvestigations (14) that used inert stimuli for examplerubber bands or paraffin wax.

Mastication is the normal, physiological stimuli forsalivation. Patients should therefore be encouraged toconsume foods which require vigorous chewing.Stimulation of the glands through mastication forexample via the use of chewing sticks may be beneficialin terms of promoting clearance of food from the mouthand may help by causing an increase in the unstimulatedflow rate on a long term basis.

Further studies should be carried out on patientswith xerostomia in an attempt to increase their salivarysecretion rate and decrease the feeling of mouth drynessby chewing meswak. When testing a saliva-stimulatingproduct such as the meswak, it is important to select arandom sample from an appropriate population that is,subjects who have xerostomia but who also have theability to produce some saliva. There is obviously nopoint in testing the effect of chewing sticks on salivasecretion rate in patients who are unable to increasetheir saliva secretion on stimulation. In individuals withnormal salivary flow, it is doubtful whether productsthat stimulate salivary flow would benefit the oral softtissues. In individuals with decreased levels of salivaryfunction, products that can increase the rate of salivaryflow may prove beneficial, depending on the cause andextent of the salivary gland hypofunction.

In summary, results of this study seemed to suggestthat plants used as chewing sticks may have the potentialof increasing the flow rate of saliva and thus the use

.of meswak may be beneficial to those with reducedsalivary secretion. Both sized meswak appeared tocontribute to a reduction in the pH of saliva. Howeverthe range of values registered after the chewing ofmeswak did not reach the "critical pH" wherebydemineralisation will follow. Further studies have tobe carried out to ascertain the therapeutic benefits ofusing meswak as an anti-plaque agent.

ACKNOWLEDGEMENTS

We would like to thank Professor Dr. Zubaidah AbdulRahim, Head of the Department of Oral Biology for heradvice throughout the course of this study, Dr. SitiLailatul Akmar and Dr. Sushil Kaur for all technicalhelp, Mr. and Mrs. John W. Johnson of Doha, QATARfor painstakingly selecting and providing us with threedifferent sets of meswak and finally, acknowledgementis made to all the volunteer subjects from the Facultyof Dentistry, University of Malaya for participating inthis study.

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