Efficacy of Bicarbonate-containing Chewing Gum on the Salivary Flow and pH in Humans
(I would make the title, “The Effect…”)
Alvin Jogasuria and Eric Taysom
Department of Biological Sciences
SaddlebackCollege
Mission Viejo, California92692
Chewing gum increases salivary flow by gustatory and mechanical stimuli. The aim(I would use purpose) of this present study was to compare the effect of bicarbonate chewing gum with the standard gum. Mouth saliva was collected from 12 participants who fulfilled inclusion criteria and gave verbal informed consent. Gum stimulated saliva was collected at various intervals during a 30 min(spell out) period of chewing bicarbonate or standard gum. Salivary volume and pH were measured for each sample and subjected to single-factor ANOVA and (one or two tailed?)paired t-tests. The mean stimulated (what do you mean by stimulated)flow rates were greater than the unstimulated(again) flow rates at all times; however, the differences were only significant up to 10 min. The peak salivary flows for the control group were 2.48± 0.80 mL/minand 2.42± 1.18mL/min(delete spaces between numbers and plus/minus symbol)for the bicarbonate gum. The peak salivary pH values occurred later than the peak salivary flow and were 7.70 ± 0.34 for the control gum and 8.00 ± 0.33 for the bicarbonate gum. Throughout the experiment, the pH of the bicarbonate gum-stimulated saliva was higher than the pH of the saliva evoked by chewing the standard control gum (two-tailed t-tests, P ≤ 0.05). Both gums types were effective in stimulating salivary flows(higher than normal??) and the pH of the salivasalivary pHwas greaterhigher with the bicarbonate gum. The higher salivary pH achieved with chewing bicarbonate gum may have important oral health implications and prevention of dental caries(????).
Introduction(Center headings)
Saliva has an important role in maintaining oral health. Saliva accomplishes its mechanical cleaning and protective functions through various physical andbiochemical mechanisms(such as??? Include a source here as well). Saliva also has a buffer capacity (or buffering capability)which neutralizes acids in the mouth. The carbonic acid and bicarbonate system is the most important buffer in stimulated saliva due to its higher concentration (Legier-Vargas 1995)(explain a little more how this system works…this statement is vague and unclear why/how it is important). The values of the bicarbonates in saliva may serve as parameters for determining the caries ??? risk patients andallow dentists to take appropriate measures to prevent caries formation. Chewing gum is one convenient way to increase salivary flow. It has been well known that both gum chewing and sodium bicarbonate are beneficial to oral health and the two have been combined in a bicarbonate containing gum. Chewing gum increases salivary flow in two ways. It increases flow by gustatory (taste) and mechanical (mastication) stimuli (Legier-Vargas 1995). It also increases salivary and plaque pH, and chewing (RUN ON SENTENCE)gum can provide an innovation for delivering medicaments such as chlorohexidine, enzymes, fluoride and whitening agents (Dawes and Macpherson, 1992).It has been shown that chewing flavored gum will increase the rate of salivary flow initially, but declines as the flavoring is lost from the gum (Dawes and Macpherson, 1992).
(A/The/One…need an introductory work) Key ingredient of baking soda, NaHCO3, was used originally in toothpaste as an abrasive (Legier-Vargas 1995), but now it can be usedto act as a base by neutralizing plaque acid(wordy) (Dawes 1997). Chewing bicarbonate gum would be expected to increase salivary pH as bicarbonate ions leach out from the gum. After the onset of chewing bicarbonate gum, the pH of the saliva would increases(grammar), but unlike the flow rate, it remains elevated after 15 min of stimulation (Dawes 1969).The objective of this present study was to measure the rate of salivary flow and the pH produced during a 30 min periods (grammar)of chewing bicarbonate-containing gum and to compare the results with a 30 min period of chewing non-bicarbonate-containing gum as the standard. (What is the control discussed in the Abstract??)
Materials and Methods
The experimentswere(only one experiment)tested on 12 volunteers (7 males and 5 females), ages 17 - 25 years, who fulfilled these inclusion criteria (explain that the criteria are described below)and (were able to give)(I would change this to “gave”) verbal informed consent. Eligible volunteers had to be non-smokers and have no significant oral or systemic disease; not taking any medication that interfere with saliva production; not under physician's care; not wearing orthodontics appliances nor having an allergy to the ingredients of the chewing gum (you don’t need the semi-colons, add a comma between non-smokers and the disease part). Prior collection period, participants were instructed to refrain from consuming any food or drink at least 1 hr (spell out)priorto investigation and to abstain from alcoholic beverages for the previous 12 hours.
Two types of chewing gum purchased from a local grocery store were used in this experiment. The control gum was sugar-free, wintermint-flavored (regular Orbit) and the experimental gum was sugar-free, spearmint-flavored gum(don’t need to say gum twice), bicarbonate containing gum (Orbit White). Both gum are manufactured (grammar)by the Wrigley Company Ltd, Chicago, IL60611. Both pellets(???) were similar in volume and mass. The average volumes and masses of the experimental and control gum pellets were 1.3 and 1.4 cm3; 1.54 and 1.58 g(need units for each number given. Also, use “respectively”, or better explain which number is which). During investigation, each gum was unmarked and indistinguishable to the test subject(couldn’t they tell by taste?).
Subjects were seated comfortably in the lab room and allowed to roam around the lab(this sentence is contradictory). Both unstimulated and stimulated whole mouth saliva collection process were monitored for a total collection period of 1 hr and 20 m(spell out units). The volume of saliva and pH measurements were taken with 10-mL graduated cylinder plastic funnel attachments and PASCO High Precision pH probe instruments (Pasco Scientific, Roseville, CA). Gum stimulated saliva was collected at intervals of 0-1, 1-2, 2-4, 4-6, 7-10, 15-20, and 25-30 minutes.Unstimulated saliva was collected over a 2 min period. During collection intervals, participants were asked to dribble(I would use a different word) their saliva into a plastic funnel. During the non-collection period, subjects were allowed to swallowed their saliva(grammar). Measurements of the salivary volume and pH were taken immediately after the collection period to avoid time-based pH changes. Within 10 seconds after collection of the sample, the volume was obtained by measuring to the top of the meniscus using the graduations on the graduated cylinder, with accuraciesup to 0.1 mL. The pH was then measured using pH probe calibrated atthe factory for a pH slope of -0.059 mV per pH unit and zero at a pH of 7(the calibration numbers are not necessary), with accuracies of 1.0 pH unit or better may be expected.
The same protocolwas then repeated for the second gum sample. It was done on the same day after a 20 minutes break period. Break periodwill (should be in past tense)allow subject's (grammar)salivary flow rates and pH to return to the basal levels. Each subject was tested on the same day rather than on separate days in order to avoid possible effects of circadian rhythms in salivary flow rate (Dawes 1992). The investigation was performed at the Saddleback College Biology Lab, Mission Viejo, CA. The samples (n=11) were collected on November 6, 2009, with appointments startedfrom 9 am to 1 pm. There was one sample taken separatelyon November 3, 2009 at 12 - 1:20 pm.
Measurements were entered into a database (Microsoft Excel, 2007) and analyzed by the General Linear Model of ANOVA using a single factor design. MegaStats, a free Excel's Add-ins(grammar), was used to calculate ANOVA values. Salivary flow and pH data within each of the control and experimental group were analyzed with single-factor ANOVA. Post-Hoc analysis, pairwise t-tests, were calculated when P ≤ 0.05(revise sentence).Two-tailed paired t-tests were used to compare the stimulated flow and pH data of the control group and the experimental group.Differences were considered significant at P≤0.05.
(Is the control group no gum chewing or non-bicarbonate gum? There are two different control groups being presented. Unstimulated suggests no gum was chewed.)
Results
Salivary flow rates.The presence of bicarbonate in chewing gum didn't(spell out) have an effect on the salivary flow rates. The mean unstimulated salivary flow rates were 0.99± 0.37 mL/min(spell out) for the control gum and 0.86± 0.43 mL/min(spell out)for the bicarbonate gum. There were no significant differences between the unstimulated salivary flow rates between the two types of gum (two-tailed t-test, P= 0.1974, P 0.05).The peak salivary flows occurred in the first minute after the onset of chewing, were 2.48± 0.80 mL/min for the control gum and 2.42± 1.18mL/min for the bicarbonate gum. There were no significant differences between the stimulated salivary flow rate of the control and bicarbonate gum (two-tailed t-tests, P = 0.8760, P > 0.05).The mean stimulated flow rates for the bicarbonate gum and control gum were greater than the unstimulated flow rates at all times; however, the differences were only significant up to 10 min(spell out).Analysis of variance indicated significance among stimulated and unstimulated data set within the groups, p = 4.19 × 10-6 for the control group and p = 1.17 × 10-6 for the bicarb(spell out here and in your figures)group. Post hoc comparisons between unstimulated and stimulated interval at 15-20 min and 25-30 min, showed no significant differences of salivary flow rates (pairwise t-tests, P 0.05).Finally, there were no significant differences between the salivary flows evoked by the two types of gum at any of the time intervals (two-tailed t-tests, P > 0.05). The results for the stimulated salivary flows are shown in Figure 2.
Salivary pH.The presence of bicarbonate in chewing gum had a pronounced effect on the stimulated pH (Fig 1)(spell out) (Figure 1 should be listed before Figure 2. Either rearrange the text or renumber the figures).The mean unstimulated salivary pH was 6.94± 0.42for the control gum and 6.97± 0.28for the bicarbonate gum. As with the flow rates, there were no significant differences between the two sets of unstimulated salivary pH values between the control and bicarbonate gum(two-tailed t-test, P= 0.8298, P 0.05).The peak salivary pH values occurred later than the peak salivary flow and were 7.70± 0.34 for the control gum and 8.00± 0.33for the bicarbonate gum. The peak pH for the bicarbonate group occurred two minutes earlier after onset of chewing, during 2-4 min, while control group reached its peak during 4-6 min. Analysis of variance indicated significance among the unstimulated and stimulated data sets within the groups, p = 1.20× 10-3 for the control group and p = 6.37 × 10-11 for the bicarb group. The mean stimulated salivary pH values were significantly greater at all time(times)than the unstimulated salivary pH (Post-Hoc, pairwise t-test, P ≤ 0.05). Throughout the experiment, the pH of the bicarbonate gum-stimulated saliva was higher than the pH of the saliva evoked by chewing the standard control gum (two-tailed t-tests, P ≤ 0.05). The results for the stimulated salivary pH are shown in Figure 1.
Discussion
The experiments showed that(only one experiment) while bicarbonate and standard gums were equally effective in stimulating salivary flow, the pH of the saliva was greater(higher) with the bicarbonate gum. The mean salivary flows for both types of gum and the mean pH response for the standard gum confirm findings previously reported (Dawes 1992). The peak salivary flow rates recorded in the present experiments were rather were rather less than those reported for some other studies, but this may reflect individual and procedural variations. The amount of gum chewed (one pellet) was smaller than has been used in many previous studies, but the single pellet was chosen as it would represent the worst case experimental scenario(why would you present a worst case scenario?? Maybe leave this sentence out). However, in the view of the participants, this was a realistic test of natural chewing conditions. In addition, participants were allowed to chew gum at their own, preferred rate, rather than having the chewing with a metronome. This lack of control of the chewing frequency should not have unduly influenced the results, as it has been shown that salivary flow rates are affected more by the mass of the gum sample than chewing frequency (Rosenhack, et al., 1993; Dawes and Puckett, 1995).
The peak pH of bicarbonate-stimulated saliva was greater than that produced by chewing the standard gum at all times. It represents a decrease in the hydrogen ion concentration of the whole mouth saliva, thus yields greater pH value(this should be included in the intro too).The salivary bicarbonate concentration is known to increase with increasing flow rate (Dawes 1969). The bicarbonate concentration of gum-stimulated saliva has been reported to increase from an unstimulated value around 4mM(spell out)to a peak of 15mM when chewing a 3 g(spell out) gum sample (Rosenhack, et al, 1993). The latter study increase the bicarbonate (grammar)concentration was very similar to the increase in salivary pH observed in the present experiment(sentence doesn’t make sense).It is thus likely that the rise in salivary pH was linked to an increase in salivary bicarbonate concentrations. The bicarbonate gum pellets contain 3%(spell out percent) sodium bicarbonate, and it is most likely that the additional increase in salivary pH with the bicarbonate gum was due to bicarbonate ions leaching out from the gum. As this reservoir diminishes with time, the differences in pH of the saliva stimulated by each gum will decreases. The rate at which gum ingredients enter the saliva has been estimated by measuring the salivary sucrose levels in participants chewing sucrose-containing gum (Rosenhack, et.al., 1993). It was found that most of the sucrose was lost over 10-15min, depending on the size of the sample (Rosenhack, et.al., 1993). These data are not consistent with the time course of the salivary pH changes induced by chewing bicarbonate gum in the present experiment (Fig.1). This study presents new findings that the bicarbonate chewing gum delayed the lost of bicarbonate by approximately 10 min, over 20-25 min interval. The higher salivary pH achieved with chewing bicarbonate gum, compared to a standard, sugar-free gum, may have important oral health implications(restate here).
Acknowledgements
The authors wish to thank Professor Steve Teh of the Biological Sciences Department, SaddlebackCollegefor his technical assistance and devotion to the success of this investigation; to thank(two different sentences)all volunteers who donated their precious saliva. Special thanks goes to Dr. Tran, D.D.S. for his suggestion on conducting this investigation.
References
Dawes, C. and Macpherson L.M. (1992). Effects of nine different chewing-gums and lozenges on salivary flow rate and pH. Caries Res. 26:176-182.
Dawes, C. (1969). The effects of flow rate and duration of stimulation on the concentrations of protein and the main electrolytes in human parotid saliva. Archives of Oral Biology.14:277-280.
Dawes, C and Puckett, D.C. (1995). The effects of chewing frequency and duration of gum chewing on salivary flow rate and sucrose concentrations. Arch Oral Biol. 40:585-588.
DePaola, D.P. (2008). Saliva: The precious body fluid. J Am Dent Assoc. 139:5S-10S.
Gracia-Godoy, F. and Hicks, J.M. (2008).Maintaining the integrity of the enamel surface: The role of dental biofilm, saliva and preventive agents in enamel demineralization and remineralization. J Am Dent Assoc. 139:25-34.
Legier-Vargas,K. (1995). Effects of sodium bicarbonate dentifrices on the levels of cariogenic bacteria in human saliva. Caries Res. 29: 143-147.
Rosenhek, M., Macpherson, L.M., and Dawes, C. (1993). The effects of chewing-gum stick size and duration of chewing on salivary flow rate and sucrose-bicarbonate concentrations. Arch Oral Bio. 38-885-891.
Review Form
Department of Biological Sciences
SaddlebackCollege, Mission Viejo, CA92692
Author (s):_ Alvin Jogasuria and Eric Taysom
Title:_ Efficacy of Bicarbonate-containing Chewing Gum on the Salivary Flow and pH in
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
The authors of this paper investigated the effect of bicarbonate gum on the amount of saliva produced and pH. The two experimental groups consisted of non-bicarbonate gum chewers and bicarbonate gum chewers. The data was collected at various time intervals from the beginning of chewing to 30 minutes. Between the two groups, there was a significant difference in the pH. However, no significant difference was found between the two groups in the amount of saliva produced.