Adaptation of dental plaque to sorbitol after 3 months' exposure to chewing gum

Five subjects used sorbitol-containing chewing gum for a period of 12 wk. Plaque was collected before and after the sorbitol exposure and also 12 wk after the termination of the exposure. The individual plaque samples were incubated with ¹⁴C-labeled sorbitol, and the medium was examined by HPLC. It was found that plaque samples from all subjects catabolized more sorbitol after the exposure. The flora adapted to sorbitol was persistent, and all the subjects had a higher capacity for metabolizing sorbitol even 12 wk after the end of the sorbitol exposure than before it. Formate, acetate, ethanol, and lactate were the major catabolites of sorbitol. Small amounts of succinate and propionate were found in some samples.     

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.     

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.     

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.     

The impact of chewing sugarless gum on the acidogenicity of fast-food meals

The objective of this study was to evaluate the effect of chewing sorbitol gum on plaque pH following the ingestion of acidogenic fast-food meals. Plaque pH response was monitored using an indwelling wire-telemetry system in five adult panelists. From a pilot study with 12 fast-food meals, the most acidogenic breakfast, lunch and dinner were selected for this study. In the first test, the fasted, resting plaque pH was recorded for 5 minutes; panelists ingested the selected meals for 10 minutes, rinsed thoroughly with 50 ml of tap water, and the pH response was monitored for the remainder of a 2-hour period. In the second test series, the same procedures were followed through the post-meal ingestion rinse. After the pH response to the meal was monitored for 5 minutes, the panelists chewed a sorbitol gum for 15 minutes in their usual manner and the panelists were encouraged to move the gum around their mouth, however, it appeared as if they favored the side of their mouth without the partial denture. The pH response was monitored for the balance of the 2-hour period. All panelists ate the test foods, with and without the chewing gum, according to a randomized-block test design. The results indicated that the use of sorbitol gum significantly raised the plaque pH, prevented the subsequent pH drops after the fast-food meal ingestion and reduced the pH curve area under 5.5.     

Effect of chewing gum containing sodium bicarbonate on human interproximal plaque pH

The effect of chewing sorbitol gum containing sodium bicarbonate on interproximal plaque pH was determined by use of an ion-sensitive field-effect transistor (ISFET) electrode system with four human volunteers. Plaque pH was lowered by 2 min of chewing of a sucrose-containing toffee. After 20 min, either sodium bicarbonate or control gum was chewed for 10 min, and the pH was followed for an additional 20 min. The minimum pH after toffee chewing was elevated by both the control gum (4.5 +/- 0.3 to 5.2 +/- 0.5) and the sodium-bicarbonate-containing product (4.3 +/- 0.3 to 6.1 +/- 0.6) to levels which were significantly different (p less than 0.01). The rate of rise in pH was 2.6 times faster with the gum containing buffer compared with the control gum. In comparison with the control gum, the sodium bicarbonate gum caused the pH to remain at a higher level, approximately 0.5 pH units, for 20 min after gum chewing. The addition of sodium bicarbonate to gum containing sorbitol markedly enhanced its capacity to cause and maintain an elevation of interproximal plaque pH previously lowered by exposure to fermentable carbohydrate. Sodium bicarbonate may be useful in products designed to reduce the acidogenic challenge to the teeth following food ingestion.     

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.     

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.     

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.     

The release of vitamin C from chewing gum and its effects on supragingival calculus formation

The aims of this study were to evaluate (i): whether vitamin C in chewing gum, alone or in combination with carbamide, influences calculus formation, and (ii) whether carbamide affects the release, stability and uptake of vitamin C in a chewing gum. In two test series (Series I and II), 30 subjects, all calculus formers, participated. They were instructed to chew on five (Series I) or 10 (Series II) pieces of gum per day for a period of 3 months. The chewing gums were: vitamin C (60 mg, Series I), non-vitamin C (Series I) and vitamin C + carbamide (30 mg + 30 mg, Series II). In both series, no gum was used as a negative control. Calculus formation was scored on three lingual sites on the six anterior mandibular teeth according to the Volpe-Manhold index. The effect on plaque and gingivitis was also determined. A significant reduction in the total calculus score was observed after the use of vitamin C (33%) and vitamin C + carbamide (12%) gums compared with no gum use; this reduction was most pronounced in the heavy calculus formers. A reduced amount of visible plaque was also observed after use of vitamin C and non-vitamin C gum, but only the vitamin C gum reduced the number of bleeding sites (37%). In a separate study, the release, stability and uptake of vitamin C were evaluated using the iodine titration method in both saliva and urine after exposure to the following gums: vitamin C + carbamide (30 mg + 30 mg) and vitamin C (30 mg). There was no indication that carbamide affected the release, stability or uptake of vitamin C when used in a chewing gum.     

An efficacy and safety analysis of a chlorhexidine chewing gum in young orthodontic patients

AIM: The objective of the present study was to investigate the impact of a chlorhexidine (CHX) chewing gum in teenage orthodontic patients on plaque levels, gingival bleeding tendency and tooth staining. MATERIALS AND METHODS: A randomized-controlled, double-blind, parallel study was conducted on 31 teenagers in fixed orthodontic therapy. Subjects of the CHX gum group were asked to continue their oral hygiene procedures in conjunction with chewing two pieces of a 5 mg CHX-containing chewing gum for 10 min. twice a day for 3 months. Subjects of the placebo gum group received the same instructions; however, using a CHX-free chewing gum. Plaque levels, gingival bleeding on probing and tooth staining were monitored at baseline and subsequently after 1-3 months. RESULTS: Plaque levels significantly decreased from baseline at lingual/palatal sites in the placebo gum group. In the CHX gum group, a similar, yet non-significant trend was observed. At buccal sites, plaque levels remained unaffected in both groups. Gingival bleeding tendency significantly decreased in both groups, predominantly at lingual/palatal sites. There were no significant between-group differences in any of the efficacy parameters at any time point. However, the increase in staining was nearly five times higher in the CHX gum group. CONCLUSIONS: There seems to be no indication for a CHX chewing gum in teenage orthodontic patients when used as an adjunct to normal oral hygiene practices.     

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。     

Clinical evaluation of the anti-plaque effect of a commercial chewing gum

OBJECTIVE: The objective of this research was to evaluate the dental plaque control effect of a chewing gum versus brushing with a dentifrice via four clinical studies. METHODOLOGY: Study 1 compared a commercial chewing gum (Colgate Dental Gum, CDG) with a water control after 24 hours post-brushing; Studies 2 and 3 compared CDG to two different brands of commercially available fluoride dentifrices after 24 hours post-brushing; Study 4 examined the anti-plaque effect of CDG plus a regular fluoride dentifrice (Colgate Winterfresh Gel, CWG) versus brushing with CWG alone for five days. The 24-hour clinical tests employed the Modified Gingival Margin Plaque Index (MGMPI), while the Quigley-Hein Plaque Index (QHPI) was used for the five-day study. All studies utilized a randomized, crossover design with a one-week washout period, and were single-blinded to the clinical evaluator. RESULTS: In Study 1, the mean MGMPI score for CDG was significantly lower (p < 0.05) compared to the water control. In Studies 2 and 3, while brushing with regular fluoride dentifrices provided improved plaque control compared to CDG, the chewing gum alone with no tooth brushing delivered a plaque reduction 60% as effective as brushing with a fluoride dentifrice. In Study 4, the group using the combination of chewing with CDG and brushing with CWG provided a significantly lower (p < 0.05) mean QHPI score compared to the group using the dentifrice only, particularly on the hard-to-brush lingual surfaces. CONCLUSIONS: Four clinical studies demonstrated that CDG provides a plaque control benefit. The results suggest that chewing gum may serve as an effective oral hygiene device when brushing may not be possible and, additionally, that chewing gum may serve as an effective adjunct to brushing for enhanced oral health.     

The efficacy of an anti-gingivitis chewing gum

Abstract Chlorhexidine is a well-established agent used for the control of supragingival plaque but is not without disadvantages, such as tooth staining, which limits its clinical applications to short-term use. This clinical trial studied the clinical effectiveness and stain-forming potential of chlorhexidine in a chewing gum base. Subjects (151) were screened for baseline plaque and gingival indices before receiving a dental prophylaxis and randomized into 3 treatment groups: group 1 chewed 2 pieces of chlorhexidine diacetate gum for 10 min 2× a day (total daily chlorhexidine=20 mg). group 2 chewed 2 pieces of placebo gum for 10 min 2× a day and group 3 rinsed with 10 ml of 0.2% chlorhexidine gluconate mouthwash for 1 min 2× per day (total daily chlorhexidine=40 mg). Plaque, gingivitis and stain evaluations were made at 4 and 8 weeks. Plaque and bleeding scores were significantly lower at 4 and 8 weeks in the chlorhexidine gum group compared to the placebo gum group and similar at 8 weeks to the rinse group. Stain intensity at week 8 was significantly less for the chlorhexidine gum than rinse. The staining measured by extent was also Jess with the chlorhexidine gum than the rinse, but the difference was not significant at week 4. At week 8, stain extent was significantly lower in the chlorhexidine gum group than chlorhexidine rinse. In conclusion, the results of this study demonstrate that this chlorhexidine chewing gum used with normal tooth cleaning provides similar adjunctive benefits to oral hygiene and gingival health as a 0.2% chlorhexidine rinse.     

Plaque removal with a novel rubber chewing wheel device: results of a randomized clinical trial

OBJECTIVE: The objective of this study was to evaluate the ability of a disposable rubber chewing wheel (Rolly Brush device) to remove plaque after meals. METHODOLOGY: This was a randomized, four-armed, investigator-blinded study where subjects were assigned into tooth brushing, mouthrinse, chewing gum, and Rolly Brush groups. Plaque index was measured before and after one of the four plaque removal techniques. Questionnaires were administered to ascertain the subject's opinion of the Rolly Brush device compared with the other plaque removal methods. RESULTS: Rolly Brush removed plaque better than mouth rinsing (p < 0.03). Subjects reported that Rolly Brush removed plaque better than mouthrinse (p < 0.001) or chewing gum (p < 0.001), but not better than tooth brushing (p = 0.365). Subjective reports indicated that the Rolly Brush device was less likely to disrupt taste compared to mouthrinse (12% versus 30% of the subjects, respectively). Subjects randomized to the Rolly Brush group also rated the device highest in terms of ease of use, although there were no statistical differences among the methods. CONCLUSION: These results suggest that a disposable rubber chewing wheel, the Rolly Brush device, is an acceptable means of removing plaque after meals, and should be well tolerated by the public.     

Effect of eucalyptus extract chewing gum on periodontal health: a double-masked, randomized trial

BACKGROUND: Studies in vitro showed that eucalyptus extracts possess antibacterial activity against cariogenic and periodontopathic bacteria; however, the clinical effects with respect to periodontal health in humans remain unproven. The objective of this study was to evaluate the effect of chewing gum containing eucalyptus extract on periodontal health in a double-masked, randomized, controlled trial. METHODS: Healthy humans with gingivitis but not deep periodontal pockets were randomly assigned to the following groups: high-concentration group (n=32): use of 0.6% eucalyptus extract chewing gum for 12 weeks (90 mg/day); low-concentration group (n=32): use of 0.4% eucalyptus extract chewing gum for 12 weeks (60 mg/day); and placebo group (n=33): use of chewing gum without eucalyptus extract for 12 weeks. Plaque accumulation (PLA), gingival index (GI), bleeding on probing (BOP), periodontal probing depth (PD), and clinical attachment level (CAL) were measured at weeks 0, 4, 8, 12, and 14. Significance was analyzed with repeated-measures two-way analysis of variance followed by the Games-Howell pairwise comparison test. RESULTS: The interaction between the effects of eucalyptus extract chewing gum and the intake period was statistically significant for PLA, GI, BOP, and PD but not for CAL. The low- and high-concentration groups exhibited statistically significant (P <0.05) improvements compared to the placebo group for PLA, GI, BOP, and PD. CONCLUSIONS: Eucalyptus extract chewing gum had a significant effect on PLA, GI, BOP, and PD. The use of eucalyptus extract chewing gum may promote periodontal health.     

Effects of xylitol, xylitolsorbitol, and placebo chewing gums on the plaque of habitual xylitol consumers

Xylitol reduces plaque but the reduction mechanism is largely unknown. The main aim of the present study was to determine whether the xylitol-induced reduction in the amount of plaque and the number of mutans streptococci could be demonstrated in subjects with (presumably) high levels of xylitol-resistant (X^R; not inhibited by xylitol) mutans streptococci acquired following previous xylitol consumptions. 37 healthy dental students participated in the double-blind study. All subjects had been uncontrolled, habitual consumers of xylitol-containing products for at least 1 yr before the study, A 1-month washout period was followed by a 2-week test period during which either xylitol, xylitol-sorbitol or unsweetened chewing gum base was chewed 3–5 × a day. Plaque and saliva samples were collected at baseline and at the 2-week point for determination of the amount of plaque, microbiological variables, and hydrolytic enzymes. Mixtures of xylitol and sorbitol seemed to perform equally well with respect to reduction in the amount of plaque but not the number of mutans streptococci. Thus, polyols were the active ingredients of chewing gums able to modulate the amount of plaque and its microbial composition. Xylitol reduced plaque with a mechanism which appeared not to be associated with the study-induced changes in the proportion (%) of mutans streptococci in plaque, the number of salivary mutans streptococci, the proportion of X^R strains in plaque or saliva, or the hydrolytic enzyme activities of plaque.     

Xylitol fermentation by human dental plaque

The aim of the present study was to examine xylitol metabolism by dental plaque collected immediately after the use of xylitol gum. Plaque was collected from 12 individuals immediately before and after xylitol exposure. The effect on xylitol metabolism by dental plaque of a 3 d discontinuation of the xylitol exposure was also examined. Xylitol metabolism by the plaque suspensions was initiated by adding [¹⁴C]xylitol and analyzed by HPLC. The results showed increased xylitol metabolism after 11 wk of chewing xylitol-containing gum. The ability to metabolize xylitol was rapidly reduced after the discontinuation of the xylitol exposure. It is suggested that an induction of enzymes in one or more of the species of plaque bacteria may have caused this effect. Glucose metabolism, which also was studied in the plaque samples, was decreased after xylitol exposure, but increased again 3 d after cessation of the xylitol exposure. It is suggested that the reduced glycolysis was caused by accumulation of intracellular xylitol-5-phosphate in some plaque bacteria during the xylitol exposure.     

Acid anion profiles in dental plaque following consumption of cereal-based foods and fruits

The aim of this study was to investigate the acid anions produced in plaque after chewing various cereal-based foods and fruits for one minute. Test foods were oranges, apples, bananas, Cornflakes®. Branflakes®, Weetabix®. Alpert®. white bread, wholemeal bread, rice and spaghetti, plus positive and negative controls of 10% sucrose and 10% sorbitol. 4 males and 3 females, aged 22–37 years, participated in the study. 7 min from the start of chewing. 48-h plaque was collected from all accessible smooth surfaces, with no attempt to collect interproximal plaque, and centrifuged. Plaque fluid was withdrawn and analyzed by isotachophoresis for formate, succinate, lactate. acetate and propionate. At rest, acetate was the major anion present in plaque fluid, whereas following carbohydrate consumption, highest levels of lactate were detected followed by acetate. The amount of lactate only, detected in plaque fluid, was significantly correlated to the carbohydrate present in the food. It was concluded that important information regarding the acidogenicity of test foods is gained by studying the acid anion profile of plaque fluid.     

Dental plaque formation and salivary mutans streptococci in schoolchildren after use of xylitol-containing chewing gum

OBJECTIVE: The aim of this study was to investigate the effect of a fixed daily dose of xylitol on mutans streptococci in saliva and the amount of visible dental plaque. A second aim was to explore if the possible effects differed between children with and without caries experience. METHODS: The study was designed as a double-blind randomized controlled trial with two parallel arms. All pupils (n=149) in grades 1-6 in a comprehensive school in northern Sweden were invited, and 128 children (mean age=12.7 years) consented to participate. The children were stratified as having caries experience (DMFS/dmfs>or=1) or not before the random allocation to a test or control group. The control group (A) was given two pellets containing sorbitol and maltitol three times daily for 4 weeks, and the test group (B) received corresponding pellets with xylitol as single sweetener (total dose=6.18 g day). Clinical scoring and saliva samples were collected at baseline and immediately after the test period. The outcome measures were visible plaque index, salivary mutans streptococci counts and salivary lactic acid production. RESULTS: The amount of visible plaque was significantly reduced in both groups after 4 weeks (P<0.05). Likewise, the sucrose-induced lactic acid formation in saliva diminished in both groups (P<0.05). The proportion of mutans streptococci decreased significantly in the test group compared to baseline, but not in the control group (P<0.05). The alterations in the test group seemed most prominent among children without previous caries experience. CONCLUSIONS: The results suggest that chewing gum with xylitol or sorbitol/maltitol can reduce the amount of dental plaque and acid production in saliva in schoolchildren, but only the xylitol-containing gum may also interfere with the microbial composition.