Association of caries activity with the composition of dental plaque fluid

This study tests the hypothesis that caries activity is associated with lower degrees of saturation with respect to enamel mineral in dental plaque fluid following sucrose exposure. Plaque fluids were obtained from caries-free, caries-positive, and caries-active subjects. Samples were collected before and at 3 and 7 min after a sucrose rinse on consecutive weeks and analyzed for organic acids, inorganic ions, pH, calcium activity, and, in selected samples, total protein. After sucrose, pH values were significantly lower in the caries-active group in comparison with the caries-free and caries-positive groups. Total and free calcium concentrations increased with decreasing pH, with free calcium being about one-third of total calcium. The caries-active group exhibited significantly lower degrees of saturation with respect to enamel mineral, after sucrose, and had significantly higher mutans streptococci levels in plaque than did the caries-free samples. Thus, saturation levels in post-sucrose plaque fluids reflect the cariogenic potential of dental plaque.     

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。     

Changes in lactate and other ions in plaque and saliva after a fluoride rinse and subsequent sucrose administration

The purpose of this study was to examine plaque and saliva composition after a fluoride rinse and subsequent sucrose application. Fifteen subjects accumulated plaque for 48 h, and then rinsed with a fluoride rinse based on 228 microg/g (ppm) Na2SiF6 and some received no rinse. After 60 min, upper and lower buccal molar plaque samples and 1-min saliva samples were collected. The subjects then rinsed with 10% g/g sucrose solution, and 7 and 15 min later, a second and a third set of samples were collected. Plaque fluid and clarified saliva were then recovered from these samples by centrifugation, and the remaining plaque acid extracted. The plaque fluid, centrifuged saliva, and plaque extract samples were then analyzed using micro techniques for pH, free calcium, phosphate, organic acids (plaque fluid and saliva only) and fluoride. Considering both the fluoride rinse and no-rinse groups, the most notable compositional changes in saliva 7 min after the sucrose rinse were pH -0.40 unit, free calcium 0.42 mM, lactate 5.2 mM, phosphate -1.3 mM, and fluoride 2.8 microM; while in plaque fluid, the corresponding changes were pH -1.59 unit, free calcium 1.5 mM, lactate 35 mM, phosphate -1.6 mM and fluoride -26 microM. After sucrose rinsing, undersaturation was found with respect to dicalcium phosphate dihydrate in saliva and plaque fluid and with respect to tooth enamel in some plaque fluid samples. Plaque fluid composition appeared to be strongly influenced by salivary clearance, diffusive loss of ions into the water phase of the rinse, and lower jaw pooling of the sucrose and fluoride components of the rinses. After the experimental rinse, the fluoride concentration in plaque fluid [86 +/- 22 mM (upper molar site), 162 +/- 150 mM (lower molar site)], saliva (26 +/- 18 mM), and whole plaque [99 +/- 97 microg/g (upper molar site), 197 +/- 412 microg/g (lower molar site)] was comparable to the values in previous studies using this rinse. These very high plaque fluid fluoride concentrations, compared with the 'no-rinse' samples, induced an approximately 0.3-unit increase in the plaque fluid pH 7 min after the sucrose rinse, a small decrease (approximately 20%) in lactate production and a modest increase in enamel saturation. Although these changes were all statistically significant, no correlation was found between the decrease in lactate concentration and plaque fluid fluoride, pH or whole plaque fluoride.     

The effect of chewing sorbitol-sweetened gum on salivary flow and cemental plaque pH in subjects with low salivary flow

The purpose of this work was to study the effect of chewing a sorbitol-sweetened gum on whole and parotid salivary flow rates, and on the cemental plaque pH response to a sucrose rinse challenge, in subjects with low salivary flow. The results show that chewing a flavored sugarless gum significantly increases salivary flow rates in individuals with dry mouth. Additionally, chewing the sorbitol-sweetened gum effectively prevents the fall in cemental plaque pH generally seen in response to a sucrose challenge. This indicates that chewing a sorbitol-sweetened gum provides a palliative and possibly a protective benefit for people who suffer from dry mouth.     

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.     

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.     

Plaque fluid pH, calcium and phosphorus responses to calcium food additives in a chewable candy

Fourteen subjects between 7 and 17 years of age with an equal distribution of low and high caries activity were given: (1) a 10% sucrose rinse, (2) a reference candy, (3) a reference candy with 3% dicalcium phosphate dihydrate, and (4) a reference candy with 0.75% calcium lactate on four different occasions. Plaque samples were collected before and at 15-min intervals after the sucrose rinse or food challenge for a period of 1 h on each occasion. Plaque samples were centrifuged and the extracellular plaque fluid analysed by a microtechnique for pH, total calcium and inorganic phosphorus concentration. There was no significant increase in calcium and phosphorus in plaque fluid for the group using candy with added calcium compared to the reference candy or sucrose rinse. There was no significant difference between the measurements in subjects grouped as caries active or inactive. The results suggest no benefit can be expected from adding dicalcium phosphate dihydrate and calcium lactate to candy to decrease demineralization during a cariogenic challenge.     

Effect in vitro acidification on plaque fluid composition with and without a NaF or a controlled-release fluoride rinse

Plaque fluid ion concentration changes, especially fluoride, in response to the pH decrease associated with a cariogenic episode are important components of the caries process. A "controlled-release" (CR) fluoride rinse, based on the controlled release of fluoride in the presence of calcium, has been shown to form large fluoride reservoirs in resting plaque. In this study, the in vitro acid-induced release of fluoride, and other ions, was examined in 48-hour-fasted plaque fluid from subjects (n = 11) who received no rinse, or who used a 228-ppm CR or NaF fluoride rinse 1 hr before being sampled. After collection, the plaque was centrifuged to yield plaque fluid, acidified (0.1 microL of 0.5 mol/L HCl per milligram plaque), and then re-centrifuged before a second sample was obtained. Although previous studies indicated a higher plaque fluid fluoride after the new rinse relative to NaF, no statistically significant difference was observed here. Average fluoride release after acidification (average pH, 5.2) was statistically greater following the use of the CR rinse (153 micromol/L) compared with the NaF rinse (17 micromol/L). No fluoride release was seen in the no-rinse samples. The pH, free calcium, phosphate, acetate, propionate, and buffer capacity were not affected by the different amounts of fluoride deposited in the plaque. However, following acid addition, an increase in free calcium and phosphate was observed, which was also independent of the rinse. The large release of fluoride following acidification suggests that the new rinse may provide an improved cariostatic effect.     

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.     

The effect of chewing xylitol gum on the plaque and saliva levels of Streptococcus mutans

Eating foods containing sucrose between meals can be highly cariogenic. The use of sucrose substitutes that provide the hedonistic appeal of sucrose, yet are not fermented by the plaque flora to the low pHs that are associated with caries, is a reasonable approach to caries control. Xylitol, a sweet-tasting pentitol, has been reported to cause about an 80% reduction in caries increment when chewed in a gum. The present investigation was designed to determine whether the chewing of xylitol gums affected the salivary and plaque levels of S mutans and lactobacilli. The chewing of xylitol gums for four weeks caused a significant reduction in saliva levels and plaque proportions of S mutans compared with pretreatment values. The levels were also significantly reduced to values obtained by chewing either sorbitol or fructose sweetened gum. The chewing of various gums had no significant effect on the proportions of lactobacilli in the plaque. These findings suggested that the small amounts of xylitol used (about 5 gm) resulted in a suppression of S mutans.     

Effect of a water rinse on 'labile' fluoride and other ions in plaque and saliva before and after conventional and experimental fluoride rinses

Labile reservoirs are important in maintaining ion concentrations in oral fluids, especially after a fluoride dentifrice application, where a persistent increase in fluid fluoride can mitigate or reverse caries progression. In this study, the effect of experimental and conventional fluoride rinses on the in vitro and in vivo water-induced release of fluoride, calcium, phosphate, acetate and hydrogen ions from oral reservoirs was examined. At the start of each experiment, 13 subjects rinsed either with a conventional 228-ppm fluoride NaF rinse, a 228-ppm fluoride controlled-release rinse (CR rinse) or received no rinse. Sixty minutes later upper and lower molar plaque samples and 1-min saliva samples were collected. The subjects then rinsed with deionized water for 1 min, and 7 min later, a second set of samples was collected (in vivo study). Plaque fluid and clarified saliva were then recovered from samples by centrifugation, and the remaining plaque mass was sequentially extracted with water and acid to measure the water-extracted and total whole-plaque fluoride (in vitro study). All the samples were analyzed using microtechniques for pH, free calcium, phosphate, organic acids (plaque fluid) and fluoride (plaque fluid, centrifuged saliva and plaque extracts). Results showed that in vivo water rinsing decreased acetate and phosphate in plaque fluid, and fluoride in plaque fluid and saliva, but had no effect on plaque fluid pH. In vivo water rinsing, however, increased plaque fluid free calcium, apparently due to water-induced loss of calcium-binding ions. Water- or fluoride-rinse-induced changes in plaque fluid concentration were greater at the lower molar site, suggesting that rinse pooling may influence ion distribution. Before the water rinse, plaque fluid, saliva and whole-plaque total fluoride values were 1.7, 2 and 4 times higher after the CR rinse compared to the NaF rinse. Furthermore, the CR rinse deposited approximately 11 times more water-extracted fluoride compared to the NaF rinse, suggesting a 'more efficient' precipitation of 'labile' or 'loosely bound fluoride'. The results presented here, and in previous studies, suggest the possibility of formulating effective fluoride dentifrices with a lower fluoride content than is currently in use.     

Effect of timing of administered calcium lactate on the sucrose-induced intraoral demineralization of bovine enamel.

A number of soluble calcium salts are known to reduce the demineralization of enamel in the mouth. The present study was undertaken to examine the effects of rinses containing different concentrations of calcium lactate, and the time of giving the rinses with respect to sucrose challenges. Subjects wore palatal appliances containing blocks of bovine enamel whose surfaces were covered with Streptococcus mutans IB 1600, and rinsed with 10% sucrose for 1 min. Changes in iodide penetrability of the enamel, and the pH and extracellular ion concentrations of the streptococcal plaque were determined. When added to the sucrose rinse, 100 or 150 mM calcium lactate reduced demineralization by about 35%, although the plaque pH was not affected. Plaque calcium was elevated but diffused away rapidly so that concentrations after 45 min were close to control values. Plaque inorganic phosphate and lactate were not affected. Ongoing demineralization appeared to be stopped when 100 mM calcium lactate was given 15 min after the sucrose rinse. When the lactate was given 15 min before the sucrose rinse, demineralization was reduced by only about 25%, consistent with the rapid diffusion of plaque calcium. The combination of (i) pretreatment with calcium lactate and (ii) admixture of calcium lactate with sucrose was most effective. Demineralization was reduced about 55% with 100 mM calcium lactate under these conditions, and protective effects were seen with as little as 25 mM. In summary, the findings demonstrate the enamel-protective effect of relatively low concentrations of calcium lactate, and point to the need to sustain a high plaque calcium during periods of maximum acidogenicity.     

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.     

牙菌斑液对牙釉质矿物的饱和程度与龋活动性的关系

为了解菌斑液对牙齿矿物饱和度随糖漱口的变化，以及与龋活动性的关系，作者选择２２例年龄相同的大学生，按龋齿情况，将其分为３组。第１组无龋（无龋组），第２组ＤＭＦＳ大于１０但无活动性龋（普通龋组），第３组ＤＭＦＳ大于１０且有活动性龋（活动性龋组），测定各受试者在静止时、用蔗糖液漱口后３ｍｉｎ和７ｍｉｎ时的菌斑液中有机酸、ｐＨ值、钙离子活度（有效离子浓度）和无机成分的含量，并计算对于釉质矿物的饱和度。结果表明，糖漱口之后菌斑液乳酸浓度升高、ｐＨ值降低、总钙和离子钙浓度增加。活动性龋组的菌斑液在糖漱口后ｐＨ值和饱和度降低的幅度明显大于无龋组和普通龋组。结论：牙菌斑液对牙齿矿物的饱和度是指示个体接受致龋食物后牙齿脱矿倾向的敏感指标。     

Effects of various forms of calcium added to chewing gum on initial enamel carious lesions in situ

The purpose of this randomized, cross-over in situ study was to determine the effects of 4 chewing gums on artificial caries-like subsurface lesions. Two chewing gums (1 with zinc citrate and 1 without) contained dicalcium phosphate (3.9%), calcium gluconate (1.8%) and calcium lactate (0.45%), 1 chewing gum contained casein phosphopeptide-amorphous calcium phosphate nanocomplexes (0.7%), and another one contained no calcium. Fifteen subjects without current caries activity (7 male, 8 female; mean age: 27.5 +/- 2.5 years) wore removable buccal appliances in the lower jaw with 4 bovine enamel slabs with subsurface lesions. The appliances were inserted immediately before gum chewing for 20 min and then retained for an additional 20 min. This was performed 4 times per day. Every subject chewed 4 different chewing gums over 4 periods of 14 days each. During a fifth period (control) the subjects only wore the appliances without chewing gum. At completion of each period the enamel slabs were embedded, sectioned and subjected to transversal microradiography. With regard to change of mineral loss and of lesion depth no significant differences could be found between chewing gums containing calcium and calcium-free chewing gums. Moreover, the chewing gum groups and the control group did not differ significantly if adjustments were made for baseline values (p > 0.05; ANCOVA). Under the conditions of the present study it may be concluded that the use of chewing gum offers no additional remineralizing benefit to buccal tooth surfaces, even if the chewing gum contains calcium compounds.     

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.     

2种胶姆糖对菌斑pH值的影响

目的：观察咀嚼2种胶姆糖后口腔菌斑pH值的变化情况.方法：选择8例健康受试者（年龄23～27岁,男4例,女4例）参加3次试验,每次实验开始前停止刷牙24h,在使用10%的蔗糖溶液漱口前以及漱口后5、10、15、20min,用Beetrode pH微电极测量口腔菌斑的pH值,作为基线值.1周后先测量静息pH值,再用蔗糖溶液漱口,1min后给予无糖胶姆糖咀嚼,在5、10、15、20min时间点,分别测量非咀嚼侧的菌斑pH值.1周后重复上述实验,胶姆糖改为含茶多酚胶姆糖.应用SPSS10.0统计软件包对数据进行单因素方差分析和SNK分析.结果：与基线值比较,咀嚼2种胶姆糖都能有效防止由于含漱蔗糖水导致的菌斑pH值下降,并使pH值维持在静息pH值以上.2种胶姆糖之间无显著性差异（P＞0.05）.结论：咀嚼2种胶姆糖均能防止菌斑pH值下降,减少患龋危险.     

Retention in plaque and remineralization of enamel lesions by various forms of calcium in a mouthrinse or sugar-free chewing gum

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) nanocomplexes incorporated into sugar-free chewing gum have been shown to remineralize enamel subsurface lesions in situ. The aim of this study was to compare the ability of CPP-ACP, with that of other forms of calcium, to be retained in supragingival plaque and remineralize enamel subsurface lesions in situ when delivered in a mouthrinse or sugar-free gum in randomized, double-blind trials. In the mouthrinse study, only the CPP-ACP-containing mouthrinse significantly increased plaque calcium and inorganic phosphate levels, and the CPP were immunolocalized to the surfaces of bacterial cells as well as the intercellular matrix. In the chewing gum studies, the gum containing the CPP-ACP, although not containing the most calcium per piece of gum, produced the highest level of enamel remineralization independent of gum-chewing frequency and duration. The CPP could be detected in plaque extracts 3 hrs after subjects chewed the CPP-ACP-containing gum. The results showed that CPP-ACP were superior to other forms of calcium in remineralizing enamel subsurface lesions.     

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 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.