The effect of chewing bicarbonate-containing gum on salivary flow rate and pH in humans

OBJECTIVE: Gum chewing increases salivary flow rate and pH. The aim of this study was to compare the effects of chewing standard sugar-free gum with those of a gum containing sodium bicarbonate. DESIGN: Whole mouth saliva was collected from 20 volunteers who met inclusion criteria and gave informed consent. After unstimulated saliva was collected, stimulated saliva was collected at intervals during 30 min of chewing either a standard, mint-flavoured gum or bicarbonate-containing, mint-flavoured gum. The salivary flow and pH were measured for each sample. RESULTS: With the standard gum, the mean peak salivary flow rate was 3.1+/-1.27 ml/min and the peak salivary pH was 7.39+/-0.14. With the bicarbonate gum, the peak flow rate was 2.79+/-1.38 ml/min and the peak salivary pH was 8.06+/-0.18. The salivary flow rates with the two gums were not significantly different; however, the increase in salivary pH was significantly greater for the bicarbonate gum. CONCLUSION: The increased salivary pH with bicarbonate gum may have implications for oral health and prevention of dental caries.     

Effect of sorbitol gum chewing on plaque pH response after ingesting snacks containing predominantly sucrose or starch

The purpose of this study was to determine the effect of chewing a sorbitol gum (Trident) for 10 minutes on interproximal plaque pH changes following ingestion of selected sucrose- or starch-containing foods. The snacks containing predominantly sucrose (and/or simple sugars) were chocolate bar, cream-filled cupcakes, cream-filled sandwich cookie, cherry pie and raisins. The snacks containing predominantly starch were oat cereal, granola bars, pretzels, potato chips and corn chips. Plaque pH responses were monitored using an indwelling wire-telemetry system in five adult panelists. The test design involved two sets of 5 x 5 Latin square randomization in which each set consisted of two series of tests. In the first series of tests, the fasted, resting plaque pH was recorded for 5 minutes, panelists ingested the designated snacks for 2 minutes, and the pH response was monitored for the remainder of a 2-hour period. In the second series of tests, the same procedure was followed through the snack ingestion. After the pH response to the snack was monitored for 15 minutes, the panelists were asked to chew one stick of sorbitol gum for 10 minutes and the pH response was then monitored for the balance of the 2-hour period. Results indicated that both the sugar- and starch-containing snacks tested in this study caused significant decreases in interproximal plaque pH. Chewing a sorbitol gum after ingestion of the snacks significantly reduced the demineralizing potential of the plaque. The chewing of sorbitol gum following the ingestion of snacks can be recommended as an adjunct to other caries-preventive oral hygiene measures.     

Effect of gum chewing following food ingestion on the pH of interproximal dental plaque.

Recent publications have suggested that chewing sorbitol- or sucrose-containing gum after a snack or meal can reduce development of caries by neutralizing dental plaque acids at interproximal sites in the dentition. To confirm these findings four volunteers wore appliances containing a miniature pH electrode. After plaque accumulation, subjects ingested a bowl of sugar-coated cereal with milk and 20 minutes later chewed a sorbitol-containing gum, a sucrose-containing gum, or did not chew anything for 20 minutes. After exposure to the cereal, the plaque pH fell within 20 minutes from approximately 6.4 to 4.8. Sorbitol gum caused the pH to rise to 5.5, while the sucrose gum caused the pH to rise to only 5.1. After cessation of chewing, the pH in all cases dropped to 4.5 or lower. No statistically significant difference could be shown between plaque pH changes with the various protocols. Gum chewing after eating caused only a transient elevation in plaque pH.     

Comparison of in vivo human dental plaque pH changes within artificial fissures and at interproximal sites

Ion-sensitive field-effect transistor (ISFET) pH electrodes were used to monitor changes in plaque pH at the base of artificial occlusal surface fissures and at interproximal sites. Bovine enamel was used to construct fissures (1.5 x 0.1 x 1.0 mm) containing a small ISFET electrode. The fissures were fixed to carrier appliances and worn by 4 human volunteers. After plaque accumulation for 4 days changes in pH were monitored by wire telemetry following 1-min rinses with 10% solutions of either sorbitol or sucrose. Results were compared to data obtained from interproximal sites in the same subjects. Responses to sorbitol in the fissure and on the proximal surfaces were minimal and showed no significant difference in minimum pH (5.9 +/- 0.4 and 6.1 +/- 0.3, respectively) and area under pH 7.0. The response to sucrose at the two sites was very different revealing unique pH profiles which were statistically significantly different with regard to minimum pH (5.0 +/- 0.3, fissure and 4.3 +/- 0.2, proximal) and area under pH 5.7. Thus, the acidogenic potential of fermentable carbohydrate at two caries-prone sites in the human dentition is significantly different and conclusions based on interproximal telemetry measurements may not be applicable to occlusal surface fissures.     

Human plaque pH responses to meals and the effects of chewing gum

Interproximal plaque pH responses to five different meals were investigated in this study. All meals were found to be acidogenic, with pH challenges lasting well over one hour. The effects of chewing one sorbitol and two different types of sucrose-containing gum for 20 minutes after the meal were examined. All three types of gum reversed the acid challenge of the meal and resulted in an interproximal pH level that is considered 'safe for teeth'. This study indicates that meals can be very acidogenic and that, in addition to normal preventive dental procedures, chewing gum for 20 minutes after meal consumption should be considered, to reduce the cariogenic challenge to the teeth.     

Prevention of sucrose-induced demineralization of tooth enamel by chewing sorbitol gum

Measurements were made of the effect of chewing sorbitol gum on the intra-oral demineralization induced by rinsing with 10% sucrose solutions. Blocks of bovine enamel were covered with a layer of Streptococcus mutans IB1600, and mounted on palatal appliances that were worn by five subjects for defined periods of time. Enamel demineralization was determined by following changes in iodide penetrability (delta Ip) of the enamel surfaces. Delta Ip increased to a maximum of about 15 units between 30 and 45 min, while the pH of the S. mutans plaque dropped to below 4 by 15 min. Plaque pH returned to 4.9 by 60 min. Chewing sorbitol gum after the sucrose rinse minimized further increases in delta Ip and brought about a more rapid return of the S. mutans plaque pH toward neutrality. The effect of chewing gum was greater when chewing was initiated earlier so that, when gum was given at five min after the sucrose rinse, demineralization was only 37% of that obtained without gum. The findings confirm earlier reports on the effect of gum on plaque pH, and directly demonstrate the profound protective effects that chewing sorbitol gum can have on tooth enamel.     

Plaque-growth inhibiting effect of chewing gum containing urea hydrogen peroxide

The plaque-reducing effect of a chewing gum containing hydrogen peroxide was assessed. 12 dental hygienist students participated in a double-blind 3 x randomly crossed-over study. During the 4-day test periods, from Monday to Friday, no oral hygiene measures were allowed other than chewing 2 pieces of gum for approximately 10 min 5 x daily. The 800 mg pieces of gum were V6+regular (V6+) containing 0.4 g sorbitol and 6.3 mg hydrogen peroxide, V6 placebo gum (PLAC) containing 0.45 g sorbitol and no hydrogen peroxide, and only the gum base (GB) as a negative control. The quantity of plaque was assessed using the plaque index and the visible plaque index, and by scraping "all" plaque off the teeth in half the mouth during 2.5 min for determination of plaque wet weight. With all 3 measurements, chewing of the hydrogen peroxide-releasing gum (V6+) resulted in significantly lower plaque increments, from Monday to Friday, than chewing of the gum base (P less than 0.05). Chewing of the V6 placebo gum (PLAC) resulted in plaque scores which differed from neither those recorded after use of the hydrogen peroxide releasing (V6+) nor the placebo (GB) gums. The observed plaque-growth inhibiting effect of the hydrogen peroxide-releasing chewing gum in the present study was found to be of limited clinical significance.     

Does the presence of xylitol in a sorbitol-containing chewing gum affect the adaptation to sorbitol by dental plaque?

It is known that xylitol inhibits sorbitol metabolism in some bacteria in vitro. The effect of xylitol/sorbitol-containing chewing gum on sorbitol adaptation of dental plaque was therefore examined. Ten subjects used this chewing gum for 12 wk, and plaque was collected before (control plaque) and after (test plaque) the exposure to sorbitol/xylitol. The metabolism of sorbitol by the plaque was examined with ^l4C-labeled sorbitol, and the radioactive metabolites were detected by high-performance liquid chromatography (HPLC). A considerable individual variation in acid formation was found. The mean values of total acids in the test plaque increased, as compared with the control plaque. An adaptation of dental plaque to sorbitol thus occurred in spite of the presence of xylitol in the chewing gum. The concentration of acetic acid predominated over other acids in both the control and test plaques. The proportions of acids expressed in percentage of total acids differed only slightly. Thus, long-term use of xylitol/sorbitol-containing chewing gum did not eliminate the adaptation of dental plaque to sorbitol.     

咀嚼口香糖对含漱蔗糖溶液后牙菌斑原位pH值的影响

目的：观察咀嚼含糖口香糖和含木糖醇口香糖对牙菌斑原位pH值变化的影响。方法：选择10名健康青年志愿者，采用受试者自身对照的临床试验方法，分别检测受试者含漱蔗糖溶液后咀嚼含糖口香糖和含木糖醇口香糖50min内牙菌斑pH值的动态变化。牙菌斑原位pH值的测定采用pH微电极接触法在口内直接测量。结果：含漱蔗糖溶液后5min开始咀嚼口香糖20min，可以明显提高牙菌斑pH值，使pH较快恢复至静止水平。咀嚼初期使用含糖口香糖牙菌斑pH无明显变化，而使用含木糖醇口香糖在咀嚼初期就可以明显提高牙菌斑pH至7．30。结论：含漱蔗糖溶液后，咀嚼无糖口香糖对牙菌斑的酸性产物产生明显的缓冲作用，提高菌斑pH值的作用较咀嚼含糖口香糖迅速而有效。     

咀嚼麦芽糖醇口香糖对牙菌斑原位pH值的影响

目的探讨咀嚼麦芽糖醇口香糖后牙菌斑原位pH值的变化趋势。方法将30名13～15岁龋易感儿童随机分为3组，即麦芽糖醇口香糖组（A组）、木糖醇口香糖组（B组）、胶母口香糖组（C组）。通过微电极原位接触法对牙菌斑pH值进行检测，观察咀嚼口香糖4W前后菌斑pH值的变化趋势。结果三组受试者分别在咀嚼口香糖后，菌斑pH值于各个时间点均呈上升趋势，约20min达到最高值，随后仍保持高于基线值水平。咀嚼口香糖4周后，三组各时间点牙菌斑pH值均上升，与咀嚼前比较具有显著性差异（P〈0．05）；三组间在各个时间点pH值上升幅度（△pH）比较具有显著性差异（P〈0．05）。结论麦芽糖醇口香糖对牙菌斑pH值的作用同木糖醇口香糖一样较为明显。     

The efficacy of a fluoride chewing gum on salivary fluoride concentration and plaque pH in children

OBJECTIVES: The purpose of this study was therefore to study the influence of different chewing times on the salivary F concentration and on the recovery of plaque pH directly after a sucrose rinse on both the chewing and the non-chewing side. METHODS: For this purpose, one piece of sugar free chewing gum was chewed to 10 healthy subjects (aged 8-10 years, 5 male and 5 female children). Subjects refrained from toothbrushing for 3 days. On the fourth day, they rinsed for 1 min with 10 microl of a 10% sucrose solutions. After 8 min, chewing gum was given and started to chew for either 5, 10, 20, 30, 45 min or control (sucrose rinse). Thus, altogether six test sessions were repeated at one week intervals. Measurements of F concentration in saliva and pH of approximal plaque were carried out at two contralateral sites for up to 60 min. RESULTS: Higher salivary F concentrations were found on the chewing side than on the non-chewing side (expressed as) (p<0.05). But, the difference between the chewing and the non-chewing side was not obvious for the plaque pH (expressed as AUC) (p>0.05). Therefore, this study showed that: (1) the F concentrations in saliva after chewing a F containing chewing gum had only small numerical differences among the various chewing times, with the exception for 5 min. All chewing time periods showed statistically significant differences between chewing and non-chewing side. (2) The prolonged chewing time increased the plaque pH recovery after a sucrose rinse (p<0.05) but there was no statistically significant difference on both of the chewing and non-chewing side (p>0.05). CONCLUSION: The results of this study indicated that a prolonged chewing time was favorable to the plaque pH recovery after a sucrose rinse and, to a certain extent, to the salivary fluoride concentration. Also it was shown that the F concentration in saliva was strongly dependent on which side the subject chewed on.     

Six-month polyol chewing-gum programme in kindergarten-age children: a feasibility study focusing on mutans streptococci and dental plaque

AIM: To investigate the use of polyol-containing chewing gums in a day-care centre (kindergarten) setting as a means to affect the growth of mutans streptococci and dental plaque. DESIGN: Over a period of six months, 123 five-year-old children chewed xylitol (X group), sorbitol (G group), or did not chew gum (C group). Consumption of xylitol, and sorbitol was 4.5 to 5.0 g per day and subjects consumed in five supervised daily chewing episodes four at the day-care centres and one at home. METHODS: Interproximal dental plaque was sampled at baseline and after six months for a laboratory study of mutans streptococci counts. The Quigley & Hein plaque index procedure was used. Interviews and questionnaires elucidated the acceptability of the programme. RESULTS: Parents and kindergarten personnel regarded the programme as an important, additional procedure to promote better oral health. The children regarded the use of chewing gum as a pleasurable experience. Compared with groups G and C, there was a statistically significant reduction of mutans streptococci in the interproximal plaque in the X group. The Quigley & Hein plaque index scores tended to decrease in the X group, while no such trend was observed in the G group. CONCLUSIONS: Habitual use of relatively small daily quantities of polyol-containing chewing gum by young children may be regarded as an important additional caries-preventive procedure in a combined day-care centre and home setting. Especially xylitol-containing chewing gum may significantly reduce the growth of mutans streptococci and dental plaque which may be associated with dental caries.     

Effect of xylitol-containing chewing gum on sorbitol metabolism in dental plaque

The aim of the present study was to examine whether a long-term use of chewing gum with xylitol as the only sweetener would affect sorbitol metabolism in dental plaque. Ten test subjects used xylitol-sweetened chewing gum for 12 weeks. Plaque was collected at three occasions; 1) Control plaque; 2) Test plaque I: plaque collected after 12 weeks of chewing xylitol-containing chewing gum; 3) Test plaque II: sucrose-stimulated plaque collected 2 d after Test plaque I was collected. Plaque suspensions were incubated with [¹⁴C]sorbitol, and uptake of sorbitol and production of sorbitol metabolites were determined by HPLC. Plaque formation and sorbitol uptake were significantly reduced.     

Effect of gum chewing on plaque accumulation

The purpose of this investigation was to test the effect of chewing gum sweetened with either sorbitol (LG) or sucrose (SG) on the growth of plaque on tooth enamel surfaces. Nineteen dental students, in a balanced crossover design, chewed the two gums for 5 days without normal oral hygiene practices. The control treatment was a 5-day non-chewing (NG) phase. A period of 9 days was allowed for normal hygiene between test phases. The chewing regimen required 20 minutes of use of one stick of chewing gum immediately after meals or snacks. The average number of sticks chewed was 3.8/day. Pre- and post-treatment plaque scores were recorded by two examiners using a Modified Navy Plaque Index (PLI) from 0 to 9 along each of four surfaces to assess six Ramfjord teeth. Pre-treatment mean PLI scores for the 3 test treatments were, NG = 2.0, LG = 1.9 and SG = 1.9. Post-treatment mean PLI scores were, NG = 3.6, LG = 3.3 and SG = 3.3. ANOVA of pre- and post-treatment scores revealed no significant differences between treatments. Post-treatment scores of the 2 chewing gums were then pooled, independent of sweetener. ANOVA of these data revealed chewing gum (LG + SG = 3.3) to cause significantly less plaque accumulation than no gum (NG = 3.6). In a no oral hygiene environment, plaque accumulation during use of sorbitol chewing gum or sucrose chewing gum was statistically the same. However, chewing gum, irrespective of sweetener, caused significantly less plaque accumulation than no chewing.     

Clinical study to evaluate the effects of three marketed sugarless chewing gum products on plaque pH, pCa, and swallowing rates

The purpose of this study was to determine the ability of three commercially available chewing gums (Extra, Trident, and CareFree) to stimulate saliva flow and reverse the plaque acid and ionized calcium levels induced by a glucose challenge. Electrodes to measure pH and pCa were situated in a Hawley appliance. When the Hawley appliance was in place, the electrodes were inserted into three day old plaque at maxillary interproximal sites. A pressure sensor, located in the posterior center of the Hawley appliance, was used to record swallowing rates. After baseline values were determined, the test procedure consisted of first administering a 5% glucose challenge solution followed by a 10 minute challenge effect period, a 5 minute gum chewing or product period, and finally a 10 minute product effect period after the test gum was discarded. An ANOVA was used to compare the ability of each chewing gum to stimulate saliva and cause a return of the plaque acid and/or ionized calcium to baseline levels following product discard. The three chewing gum products varied in both time and level of pH attained while neutralizing plaque acidity (p less than .05) induced by the glucose rinse. No significant differences were found between the chewing gums for the pCa data and swallowing rates. All chewing gum products stimulated swallowing and effectively reversed plaque pH and pCa changes caused by the glucose rinse.     

Reduction of the formation of dental plaque and gingivitis in humans by crude mutanase

abstract — The effect of a Trichoderma harzianum enzyme preparation containing mutanase (α-1,3 glucan glucanohydrolase) on plaque accumulation and composition and on occurrence of gingivitis was assessed in 20 persons in a double-blind cross-over investigation. The enzyme preparation was administered in chewing gum. Two test periods of 1 week were preceded by scaling and cleansing of the teeth, oral hygiene instruction, and controlled hygiene for at least 3 weeks. Oral hygiene measures were discontinued during the test periods, while the persons chewed six pieces of chewing gum per day, one half using enzyme-containing gum, and the other half using placebo gum. The test periods were identical, only enzyme gum was used instead of placebo, or vice versa . Evaluations of plaque and gingivitis showed that less plaque had accumulated and less gingivitis developed during the enzyme than during the placebo period, but bacteriologic studies of interproximal plaque did not reveal differences that could explain the clinical findings. Treatment with the enzyme preparation caused some local side effects, but no primary skin irritation, delayed hypersensitivity, nor anti-enzyme IgE was detected in any of the persons.     

咀嚼无糖口香糖对含漱蔗糖溶液后牙菌斑原位pH值的影响

目的 通过对牙菌斑原位pH值变化的动态监测，观察咀嚼无糖口香糖对牙菌斑原位pH值的影响。方法 采用受试者自身对照的临床试验方法，选择16名健康成人志愿者为受试者，年龄23～32岁，其中男性6名，女性10名。首先测定受试者48h菌斑的静止pH值，以及受试者用10％蔗糖溶液含漱1min后在5、10、20和30min时菌斑的pH值，取得受试者的Stephan曲线作为基线对照；而后观察咀嚼两种益达无糖口香糖对含漱10％蔗糖溶液后菌斑pH值变化的影响。菌斑原位pH值的测定采用pH微电极接触法在口内直接测量。结果 含漱10％蔗糖溶液后立即开始咀嚼无糖口香糖可使菌斑pH值在各检测时间点(含漱10％蔗糖溶液后5、10、20和30min)均维持在静止pH水平，无明显下降；含漱10％蔗糖溶液后在5min时开始咀嚼无糖口香糖则使菌斑pH值从含漱蔗糖溶液后5min时的5．59迅速回升至10min时的6．98。结论 受到蔗糖攻击后，咀嚼无糖口香糖可迅速缓冲菌斑的酸性产物，升高菌斑pH值。     

The effect of chewing urea-containing gum on plaque acidogenic and alkaligenic parameters

The aim of this double-blind crossover study was to determine the effect of chewing urea-containing gum on selected microbiological plaque properties. Eleven subjects chewed either urea-containing or urea-free placebo gum 3 times daily, each for 4 weeks, with at least a 4-week separation between regimes. After each chewing regime, plaque was sampled from all available surfaces, and inoculated into media indicative of acid or base production. In addition, interdental pH measurements were taken using touch Beetrode electrodes following sucrose and sorbitol mouthrinses, and sucrose mouthrinses followed by urea rinse, urea gum, or placebo gum. No significant differences in plaque acidogenic and alkaligenic properties were found between the urea and placebo gum regimes. Urea rinsing, urea gum and placebo gum all reduced the depth and duration of the pH fall following a sucrose mouthrinse. They also enhanced a rise in pH above the resting pH, but although urea gum produced a larger increase than placebo gum, the difference was not significant.     

Plaque growth while chewing sorbitol and xylitol simultaneously with sucrose flavored gum

In a recent study, sorbitol flavored chewing gum was found neither to increase nor decrease the normal rate of plaque formation, whereas high plaque scores were obtained with sucrose gum during 4 days of no mechanical tooth cleaning. The aim of the present study was to see if chewing sorbitol or xylitol flavored gum together with sucrose gum would affect the growth rate of plaque and whether chewing of xylitol flavored gum could reduce the amount of already formed plaque. Twenty-seven dental students refrained from mechanical oral hygiene measures from Monday to Friday morning for 3 weeks. The students were randomly divided into three groups. A three time crossed-over double-blind approach was used. During each test period one group chewed a combination of one piece sorbitol and one piece sucrose flavored gum five times per day, the second group correspondingly chewed xylitol and sucrose flavored gum, while the third group served as a no hygiene control group. After each test period the students in the control group chewed one piece of xylitol gum every 15 minutes for 2.5 hours. The participants started out each week with clean teeth and were at the end of each test period scored for visible plaque on the facial, mesial and lingual surfaces of their teeth. There was somewhat more plaque after 4 days of chewing sucrose-sorbitol and sucrose-xylitol gum combinations than after no oral hygiene alone. There was no difference between the two test treatments. The 2.5-hour chewing of xylitol flavored gum after the no oral hygiene period did not result in a reduction of the 4-day-old plaque.     

Salivary concentrations of urea released from a chewing gum containing urea and how these affect the urea content of gel-stabilized plaques and their pH after exposure to sucrose

The objectives were to: (1) determine the salivary concentrations of urea during 20 min chewing of a sugar-free gum containing 30 mg of urea; (2) measure the degree to which this urea would diffuse into a gel-stabilized plaque; (3) study the effect of the urea on the fall and subsequent rise in pH (Stephan curve) on exposure to 10% sucrose for 1 min; (4) model the measurements 2 and 3 mathematically. In point 1, the salivary urea concentration of the 12 subjects peaked at 47 mmol/l in the first 2 min of gum chewing, falling within 15 min to the unstimulated salivary concentration of 3.4 mmol/l. Recovery of urea from the saliva averaged 81.5%. 'Plaques' of 1% agarose or 67% dead bacteria in agarose accumulated urea from the saliva roughly as expected, whereas those plaques containing 8% live and 59% dead Streptococcus vestibularis showed negligible accumulation. Computer modelling showed this difference to be due to urease of live bacteria breaking down the urea as rapidly as it entered the plaque. Simulation of the effect of gum chewing subsequent to initiation of a Stephan curve in the latter type of plaque showed a rapid rise in pH but then a fall again on return to unstimulated conditions. This fall had not been seen in previous studies, with Streptococcus oralis, nor was it predicted by the computer modelling. Neither experimental simulation nor computer modelling suggested that chewing urea-containing gum before exposure to sucrose would have any effect on a subsequent Stephan curve. Thus chewing gum is only likely to inhibit caries when it is chewed after consumption of fermentable carbohydrate, rather than before.