The effect of two types chewing gum containing casein phosphopeptide-amorphous calcium phosphate and xylitol on salivary Streptococcus mutans

Abstract

Aim:

The aim was to evaluate the effect of sugar-free chewing gum containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol on salivary Streptococcus mutans.

Materials and Methods:

A total of 60 dental students of 20-25 years old, who volunteered after checking their health condition and signing an informed consent, were randomly allocated to receive one of the following interventions: (A) Chewing gum containing CPP-ACP; (B) containing xylitol. Subjects within the experimental groups were taken the gums 3 times daily, after each meal for a period of 3 weeks. Pre- and post-intervention unstimulated saliva samples were quantified for S. mutans counts.

Results:

A statistically significant reduction of salivary S. mutans was displayed in both groups A and B after the intervention when compared with baseline (P < 0.001), and group A shows more statistically significant reduction of salivary S. mutans than group B (P = 0.011).

Conclusion:

Daily consumption of chewing gum containing CPP-ACP and xylitol significantly reduces the level of salivary S. mutans, but chewing gum containing CPP-ACP can reduce the level of salivary S. mutans in more than xylitol chewing gum.

INTRODUCTION

Bacterial plaque that accumulated on teeth surfaces and composed of native oral flora is the primary etiological agent for periodontal disease and dental caries which may result in teeth loss if left untreated.[1,2] Dental caries is the destruction of dental structures by acid product as a product of carbohydrate metabolism by cariogenic bacteria.[3] Streptococcus mutans, commonly found in human dental plaque, are the primary species associated with dental caries.[4] S. mutans is now considered to play an important role in the development of dental caries in animals and humans. Extensive research on this microorganism has been done during the last 10 years.[5]

Chewing gum is known to be a useful adjunct to common oral hygiene because of stimulation of salivary flow rate. It is effective in raising plaque pH. The chewing of sugar-free gums after meals and snacks can promote remineralization of enamel and reduce S. mutans rate.[6]

In recent years, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) noncomplexes have also been demonstrated to have anticariogenic properties in both laboratory animal and human in situ experiments.[7,8] CPP containing the cluster sequence −Ser(p)-Ser(p)-Ser(p)-Glu-Glu- has a remarkable ability to stabilize ACP in metastable solution.[9] When delivered in sugar-free chewing gum, CPP-ACP has also been shown to remineralize enamel subsurface lesion and reduce S. mutans in vivo, independent of chewing frequency and duration.[10,11]

Xylitol, a five-carbon natural sugar alcohol, is widely used as a noncariogenic sweetener, which is not fermentable by most oral bacteria.[12] Several studies have shown that xylitol can also reduce dental plaque as the number of S. mutans (in vivo and in vitro).[13] The aim of the present study was, therefore, to compare the effect of xylitol and CPP-ACP chewing gums, on the level of S. mutans in the saliva of young adults.

MATERIALS AND METHODS

This was a randomized, stratified block, controlled clinical trial with parallel groups that registered at IRCT.com.

A total of 60 young adults (37 women, 23 men) who volunteered, after signing an informed consent, were selected. Eligible persons were dental students who had healthy condition and were between the ages of 20 and 25 years old. Exclusion criteria were any abnormal oral, medical or mental condition (including any milk-related allergies and medical condition involving the kidneys), a history of systemic antibiotic or topical fluoride treatments within a 4 weeks period before baseline, individuals with a habitual use of dairy xylitol or recaldent chewing gums, any untreated caries lesions or clinical signs of either gingivitis or periodontal disease.

This clinical trial had two parallel groups (each size group = 30). Each group chewed 3 gum pellets, 3 times/day for an experimental period of 3 weeks. Subjects were randomly assigned to groups by a stratified block randomization procedure. Group A consumed three chewing gums containing CPP-ACP 3 times daily after each meal; group B was given three chewing gums containing xylitol 3 times daily after each meal. Salivary samples were collected at baseline and 1-day after the final gum consumption. During the experimental period, the subjects were strongly encouraged to reduce their carbohydrate diet and brush their teeth twice a day with fluoride toothpaste.

Each recaldent pellet (Trident Company, Thailand) contained 10% CPP-ACP plus gum base and the xylitol chewing gum (Orion Company, Rasti Lar Company, Iran) contained 55.3668% xylitol. The ingredients of the gums are listed in Table 1. The participants were instructed to actively chew on the assigned gums during 20 min after the meals; in the morning, at noon, and evening.

Table 1.

Ingredients of the chewing gums according to the manufacturers’ declaration

Unstimulated saliva was collected in the morning (9:00 am) on the day before onset and 1 day after the intervention period in the 1.5 cc test tube. The counts of salivary S. mutans were evaluated using mitis Salivarious agar (merk) as described. After cultivation at 37°C with CO₂3% for 48 h, the colony forming units were identified on the basis of their morphology and counted in a stereomicroscope with 12-25 times magnification. The results were categorized in 3 scores, and the data were processed with the SPSS software (version 18, SPSS, Chicago, IL, USA).

RESULTS

All subjects completed the trial, the compliance was excellent, and no side effects were reported. The preintervention and postintervention reports are shown in Table 2. All subjects had detectable levels of S. mutans at baseline, and there were no statistically significant differences between the two groups concerning the distribution of scores. One day after the 3-week intervention period, significantly reduce levels (P < 0.05) of S. mutans compared to baseline in both groups A and B. Group A shows more statistically significant reduction of salivary S. mutans than group B.

Table 2.

Counts of S. mutans preintervention and postintervention

DISCUSSION

A significant part of studies has been focused on studying the effect various substances for preventing dental caries in the primary stages. S. mutans is the effective bacteria on the beginning of the process of demineralization of enamel and consequently decays, hence using an appropriate solution for controlling or eliminating these bacteria can prevent the creation of decay.

In the present study, we assessed the effectiveness of xylitol and CPP-ACP chewing gum in reducing load of S. mutans as cariogenic agents.

Although the usefulness of xylitol for preventing dental caries especially in patients with primary caries has been documents,[14,15,16] But since so far the effect of these two types of chewing gums on the S. mutans rate in saliva have not been compared with each other clinically, hence the present study has been developed and conducted.

In the present research, considering the effect of caries on the number of S. mutans of saliva, those individuals with active caries have been eliminated from the study. In addition, with matching the health and nutrition programs such as do not using any other xylitol and CPP-ACP products and mouthwash and fluoride gel, it has been tried to eliminate the intervening variables as much as possible.[17]

In the current study, the time of sampling has been performed at 9 am and while fasting that this method of sampling is consistent with the sampling method in the study of Caglar et al.[17]

In this study, the patients were asked to use the provided chewing gums were used for a time period of 3 weeks, 3 times a day after eating their main meal. Researchers believe that for evaluating the effects of each chewing gum on the counts of S. mutans in saliva, the chewing gums should be used immediately after taking the main meal for 3 weeks.[18,19]

The individuals were asked to use the chew the chewing gums every time for 20 min. According to the studies of Harris et al., and Iijima et al., after 20 min of chewing the gums, the secretion rate of saliva becomes 3 times and also due to increasing the level of pH and increasing the mineral deposition of calcium and phosphate ions present in saliva, enamel become remineralized.[11,18]

In this study, the S. mutans rate in saliva after 3 weeks of using chewing gums containing xylitol has decreased significantly (P < 0.0011). This finding is consistent with the study of Fraga et al.[20]

The reason that xylitol has the amounts of reduced S. mutans might be due to the inability of 5-carbon sugar xylitol to be fermented by S. mutans furthermore, because chewing stimulates salivary flow, which improves the buffering of the pH drop that occurs after eating, the growth of these bacteria reduces.[20]

In so many studies, xylitol has caused the reduction of S. mutans in saliva that is consistent with the findings of the present study.[16,21,22,23]

In this study, the rate of S. mutans in saliva had a significant reduction (P < 0.001) after 3 weeks of consumption of chewing gums containing CPP-ACP that this finding is in agreement with the study of Subramanian and Naidu and Vashisht et al.[24,25]

In the present study, although in both groups the rate of S. mutans in saliva after the consumption of the chewing gums have shown a significant decrease; however, the rate of S. mutans in saliva in the group of xylitol is significantly higher comparing to CPP-ACP group that can be due to the antibacterial properties and its buffering effect on plaque and prevention of growth and attachment of Streptococcus strains to the teeth. This study has documented and demonstrated the clinical antibacterial effects of CPP-ACP and its effect as an anti-caries agent (in primary caries).[25]

All individuals, especially those who are in danger of the development of dental caries can use these substances; however, more clinical long-term studies in this regard are required.

CONCLUSION

Daily chewing gum containing CPP-ACP and xylitol reduce the level of salivary S. mutans significantly, but chewing gum containing CPP-ACP can reduce the level of salivary S. mutans in a significant way than xylitol chewing gum.