The Role of Sugar-Free Chewing Gum in Dental Caries Prevention

Abstract

The key to avoiding dental caries is managing the microorganisms on the tooth responsible for demineralization. Chewing gum has physical adhesive capabilities. It also promotes saliva flow, assisting in eliminating food particles and reducing the formation of bacterial biofilms in the oral cavity. Saliva flow also helps to balance the pH balance in the oral cavity, thereby reducing the risk of dental caries. In addition, sugar-free gum contains various antibacterial and remineralization substances, such as xylitol and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). In conclusion, sugar-free gum can remove food particles and tartar, stimulate saliva, increase oral pH, inhibit demineralization, and increase remineralization. These qualities aid in preventing dental caries.

1. Introduction

Oral health is an important problem for public health, especially dental caries, which have a relatively high incidence rate. Dental caries is not a severe disease but causes economic loss, pain, and suffering. In addition, the inability to chew food, bad breath, and lesions in the tooth are breeding grounds for bacteria that weaken the body and lead to other diseases. Despite the campaign to disseminate dental health knowledge to people of all ages to realize the problem and pay attention to oral health, dental caries is still a problem for people of all ages. Especially among children, the leading cause of dental health problems is improper dietary habits and improper oral health care [1]. In addition, parents have incorrect oral health care attitudes and a lack of knowledge about dental caries prevention, resulting in children not receiving proper treatment. Dental caries is caused by four factors: the tooth, food, bacteria, and the time of tooth surface acid exposure (Figure 1).

Figure 1.

Caries process.

Food particles adhered proximally and in the groove of the tooth produce dental caries. It provides energy to the bacteria in the oral. The process by which bacteria break down food debris produces acid, leading to the demineralization of tooth. Therefore, when food remains in the oral for a long time or is frequently eaten, it often causes the demineralization of tooth, thus causing dental caries (Figure 2). School-age children are a group at high risk of developing dental caries. Many factors involve biological, social, behavioral, and psychological factors. Therefore, dental caries is still a problem among school-age children. Especially during the age of 9 years, when the premolar and molar tooth are coming. Therefore, there is a chance of quickly accumulating food particles in the tooth’ grooves [2].

Figure 2.

Caries process.

There are many ways to prevent caries by controlling the causative factors of dental caries, including the tooth, food, bacteria, and time. The most commonly used methods are physical methods such as brushing tooth and chemical treatments such as fluoride. Brushing tooth with fluoride toothpaste is a common practice these days, but cavities still occur due to many factors, such as the frequency of overeating; as a result, brushing tooth three times a day is insufficient to stop dental caries progression. Therefore, it is necessary to control the risk of caries during the day. Sugar-free gum is a good choice because the adhesive gum’s physical nature helps eliminate food residues after eating food by attaching the direct contact of the gum to the food scraps. In addition, chewing gum increases saliva flow reduces bacterial biofilm on the tooth surface, and maintains oral acid-base balance (pH > 5.5) [3, 4]. In addition, sugar-free gum contains a variety of substances that have antibacterial and remineralizing properties, such as xylitol and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), so sugar-free gum is more responsive to oral health care.

2. Sugar-free chewing gum and oral health

Sugar-free gum is chewing gum that uses a sweetener instead of sugar. Popular sweeteners such as xylitol, sorbitol, and mannitol [5]. The general composition of chewing gum includes sweetener (50–65%), gum base (18–30%), corn syrup (12–20%), color and flavor (1–2%), and softeners (0.3–3%). More than half of the composition is sweetener, which is responsible for enhancing the flavor and texture of the gum [6]. Sugar-free gum has significantly impacted oral health because of its ability to stimulate saliva and accelerate the removal of carbohydrates that accumulate from food intake. These actions may lead to healing, reduction of tooth decay, and other oral health benefits [7]. The benefits of chewing gum on oral health are as follows: (Figure 3)

• Remove food particles and dental plaque.

• Stimulate saliva.

• Increase plaque pH.

• Inhibit demineralization and enhance remineralization.

Figure 3.

The anti-cavity mechanism of chewing sugar-free gum.

Nowadays, sugar-free gum has been produced for consumers to choose from in various styles. Chewing gum is another good way to clean tooth. Chewing gum may be used as auxiliary to dental brushing or when such method is impossible to be performed, such as when you are outside, and it is not convenient to brush your tooth, you can chew gum to clean your tooth. Chewing sugar-free gum for 5–20 minutes after meals two to three times a day can help prevent tooth decay because gum helps to remove plaque and reduce gum inflammation. In addition, sugar-free gum stimulates saliva, which reduces acidity on the tooth surface and helps to self-cleansing can clean tooth [3, 8]. Several studies have concluded that sugar-free gum can inhibit the effects of oral bacteria [3, 4, 8]. This process is due to two main reasons: (1) the stimulation of saliva from chewing and (2) the use of sweeteners instead of sugar [9]. In addition, some substances promote healthy tooth, such as xylitol, andCPP-ACP, also known as Recaldent, which has been reported to enhance remineralization of the tooth surface [10, 11, 12]. A study on sugar-free gum chewing found that children who chewed sugar-free gum had fewer cavities than children in the control group who didn’t chew gum [4, 13]. In addition, sugar-free gum was tested to prevent tooth decay in students. The students chewed 1 tablet of gum for 10 minutes after eating breakfast-afternoon every day. It was found that after 4 months of the experiment, the students had no more tooth decay [3, 8].

2.1 Compounds that affect oral health

2.1.1 Xylitol

Xylitol is a type of sweetener which is alcohol sugar. Xylitol was discovered in 1890 by German chemists Professors Emil Hermann Fischer and Rudolf Stahel by extracting the compound from beech [14] and later widely known in many countries such as the United States, Canada, Japan, etc. Xylitol has a molecular structure of 5 carbon atoms (Figure 4), chemical formula C5H12O5, and a molecular mass of 152.15 g/mol. Xylitol is a common sugar substitute. It is as sweet as sucrose. It can be used instead of sucrose in a ratio of 1:1, providing 2.43 cal/g of energy. In addition, it has the property of giving a cooling sensation while eating. Xylitol is a non-fermentable sugar that bacteria cannot use to synthesize for energy. Therefore, Xylitol is used as a glycemic control agent in Type 2 diabetes and as a product to prevent tooth decay [15].

Figure 4.

Structure of xylitol.

Xylitol has been approved by the U.S. Food and Drug Administration (FDA) since 1960 as safe for children [16] and can be consumed in 30 g without causing harm. If consumed more than 30 g at a time can cause diarrhea. This may be because intestinal bacteria cannot metabolize large amounts of xylitol. In nature, it can be found in many natural plants, vegetables, and fruits, such as strawberries, carrots, corn cobs, nuts, etc. Marketing xylitol is available in liquid and solid form. Its applications are mainly made into chewing gum, followed by confectionery, medicine, and beauty products [17]. In addition, Xylitol is recognized by the American Academy of Pediatric Dentistry (AAPD) and serves as a guideline for tooth decay prevention [18]. Xylitol has anti-cavities properties for two reasons: promoting remineralization and inhibiting caries-causing bacteria (Figure 5).

Figure 5.

The anti-cavity mechanism of xylitol.

2.1.2 Casein phosphopeptide-amorphous calcium phosphate

CPP-ACP, also known as “Recaldent”, was discovered by Professor Eric Reynolds, School of Dental Science, University of Melbourne, Australia. CPP-ACP is divided into casein phosphopeptide (CPP) and amorphous calcium phosphate (ACP). CPP is a peptide derived from cow’s milk by tryptic digestion of casein in cow’s milk to produce a peptide containing phosphoseryl residue (Ser(P) – Ser(P) – Ser(P) – Glu – Glu –) a large amount of which binds calcium and phosphate in the ionized form to form a complex called ACP, which can cause calcium and phosphate ions. It is in a saturated state called metastable solution, i.e. it is saturated but does not form nucleation and does not precipitate calcium salts and phosphates, thus forming a nanocomplex between CPP and ACP known as CPP-ACP [19].

CPP-ACP has been proven to prevent tooth decay in laboratories, in vivo, and in humans; its efficacy is due to casein’s ability to adapt to acidic environments. When the pH is acidic, the ACP is separated from the CPP, resulting in an increase in the levels of calcium and phosphate in the saliva, stabilizing the oral ACP [10] and increasing the calcium and phosphate content in the plaque. Furthermore, as an ion reserve, it inhibits demineralization [20] and stimulates the remineralization of tooth enamel by preventing the constant precipitation of calcium and phosphate in saliva [21]. It was also found that CPP directly affects bacterial apoptosis and impairs agglutination [22]. CPP-ACP can work with fluoride to form casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP), readily strengthening enamel [20].

The continued use of dental products containing CPP-ACP produces ion saturation in saliva and biofilm, making it available for subsequent precipitation in the form of ACP, favoring the dental remineralization process. The process of dental demineralization/remineralization: (1) oral pH < 5.5 causes demineralization of hydroxyapatite (HA), chemical formula Ca₁₀(PO₄)₆(OH)₂ (2) upon saturation of the oral environment and biofilm with Ca²⁺ and PO4³⁻ ions, promoting the process of remineralization (Figure 6) [23].

Figure 6.

Remineralization mechanism of CPP-ACP.

In 1999, CPP-ACP was approved by the FDA that it is safe. CPP-ACP can be used in people with lactose intolerance because CPP-ACP does not contain lactose. However, CPP-ACP is not recommended for people with milk protein allergies [24]. CPP-ACP is used in various applications in food ingredients such as sugar-free candies or gum and in dental products such as toothpaste, mouthwash, dental implants, and glass ionomers. It is also available as a topical cream (paste) for ease of use [8].

3. Chewing gum and removing food particles on the tooth surface

Food debris is a factor in dental caries due to the accumulation of food particles in the mouth or on the tooth, especially starchy foods, which are the main energy source for bacteria. When the digestive bacteria are energized, they make acidic wastes that cause tooth demineralization. Therefore, removing food particles stuck in the tooth is necessary to prevent tooth decay. It is known that the gold standard for removing supragingival plaque is daily tooth brushing, flossing, and/or use of antimicrobial mouthwash. Still, in some cases, chewing gum may be used as auxiliary to dental brushing, or when such method is impossible to be performed. This led to the development of antimicrobial gum that would provide daily oral care and reduce plaque in the mouth [25]; due to the physical nature of gum as a binder, it helps to eliminate food residues left after food consumption. Due to the physical nature of gum as a binding agent, it helps to eliminate food residue after consuming food. Disposal is partly due to the direct attachment of the gum to the food debris, along with the increased occlusion and saliva, which washes away the food particles [8]. In case we are outside, and it is not convenient to brush our tooth, it is possible to chew sugar-free gum to clean the tooth. In addition, a research report concludes that chewing gum may be used as an aid to flossing when brushing is impossible [26]. In addition to removing food particles, chewing sugar-free gum reduces plaque on the tooth caused by the accumulation of food particles on the tooth surface [27].

Phoophaniat and Joankrajang [8] examined the effectiveness of chewing gum containing CPP-ACP and xylitol in preventing dental caries in school-aged children. The sample group consisted of 90 students, divided into 3 groups by simple random sampling. A group of 30 students received one of the following interventions: experimental group 1 used chewing gums containing CPP-ACP, experimental group 2 used chewing gums containing xylitol, and control group. The experimental groups chew gums for 10 minutes, times times a day for 16 weeks. The dental plaque was assessed five times: before the trial, week 4th, week 8th, week 12th, and week 16th. Dental caries was assessed twice, before and after the trial. The data were analyzed by the friedman test, wilcoxon signed ranks test, kruskal-wallis test, and mann whitney U test. The result showed that there was a statistically significant decrease in dental plaque level in experimental groups, experimental group 1 had mean dental plaque of 1.10, 0.83, 0.40, 0.16, and 0.13 (${\chi }^2$ = 75.835, P-value < 0.001), and experimental group 2 had mean dental plaque of 1.00, 0.93, 0.51, 0.16, and 0.14 (${\chi }^2$ = 66.905, P-value < 0.001), and less dental plaque than the control group. Experimental group 1 (Z = −1.000, P-value = 0.500) and experimental group 2 (Z = −1.414, P-value = 0.250) dental caries did not increase compared to before the trial, and less tooth decay than control group (${\chi }^2$ = 7.164, P-value = 0.030). Suggestions that chewing gum containing CPP-ACP or xylitol, 1 tablet for 10 minutes, can reduce dental plaque. Consistent a study on chewing sugar-free gum in students found that students chewing one tablet of gum for 10 minutes after breakfast and afternoon daily was found to reduce the formation of dental plaque within 4 weeks and decreased dramatically at week 8 and then started to stabilize at week 12 because the amount of plaque on the tooth was already very low [3], consistent with research that found that most gum containing sugar substitutes, antimicrobial agents, and other minerals have an effect on reducing plaque [28]. The reduction of food particles and plaque on the tooth is one of the causative factors of tooth decay due to the physical nature of the gum and its beneficial compounds.

4. Chewing gum and oral bacteria reduction

Oral bacteria are endemic to everyone and are a common cause of oral health problems. The bacteria known as Streptococcus mutans are the main culprits that cause tooth decay. Controlling Streptococcus mutans can help reduce tooth decay. Dental plaque begins with a biofilm that binds the tooth surface between the saliva covering the tooth surface and bacteria. The physical nature of chewing gum helps to eliminate food debris, which is the energy source of bacteria, preventing them from growing [8]. In addition, sugar-free gum has other properties that eliminate bacteria, such as:

Xylitol is a sweetener instead of sugar. Xylitol molecules similar in shape to fructose are absorbed through the bacterial cell wall by the same mechanism that bacteria absorb sugar into cells. When xylitol gets into cells, bacterial enzymes cannot synthesize xylitol for energy, so bacteria cannot survive. Xylitol is a substance that helps reduce bacteria in the oral [8]. When compared to other oral bacteria, xylitol is more effective in inhibiting Streptococcus mutans [29]. Consistent with research findings, the samples had reduced plaque after 21 days of chewing gum containing xylitol [30]. Similarly, the research found that after chewing gum containing xylitol for 30 days, the samples had reduced plaque content. Thus confirming that chewing gum containing xylitol can reduce plaque [31].

CPP-ACP can increase calcium and phosphate in plaque. When there are many calcium ions in the extracellular fluid, the bacterial cell wall becomes porous, and the cell breaks down. This results in killing bacteria or inhibiting bacteria [12]. In addition, chewing gum can help stimulate the flow of saliva to produce more secretions than usual [3]. The secretion of saliva and the physical nature of the gum as a binding agent facilitates the removal of food residues left after ingestion. The elimination is partly due to the direct attachment of the gum to food particles. This, together with increased occlusion and saliva, thus prevented bacterial formation and reduced the appearance of oral bacterial biofilms, consistent with the results of a study by Phoophaniat et al. [4, 8] that after chewing CPP- ACP for 12 weeks, subjects had a statistically significant reduction in dental plaque content.

5. Chewing gum and oral pH balance

It is well known that oral pH is an integral part of the caries process. It comprises acidogenic and aciduric bacteria that are responsible for lowering the pH and subsequent destruction of HA matrix in enamel and dentine. Therefore, preventing tooth decay requires maintaining a pH balance that is not too low (<5.5). Chewing gum has a physical mechanism in which chewing stimulates saliva flow. It is commonly known that saliva is the pH balance system in the oral. Therefore, when there is a lot of saliva flowing, it helps to balance the pH of the oral cavity. In addition, the properties of compounds that have a positive effect on oral health also help to improve the pH balance in the oral cavity [8], as follows:

Xylitol has been reported to increase saliva flow and adjust oral pH [14, 32]. This may be due to its cooling effect on xylitol, which stimulates salivary flow. Together with the properties that help eliminate bacteria in the mouth, thus making the pH value not lower because bacteria cannot synthesize xylitol. It is not acidic, like digesting sugars in general [15]. Tests of various brands of xylitol gum were found to increase pH within 15 minutes. There was a statistically significant difference with the control group [33]. Consistent with the test in children 8−10 years, it was found that after chewing gum with xylitol, saliva pH immediately increased and increased dramatically in 15 minutes [34].

CPP-ACP has the property to increase the pH of saliva by casein modulating an acidic environment [10]. ACP refining cleaves from CPP, resulting in increased calcium and phosphate levels in saliva. Therefore, conditions within the oral cavity become basal according to the properties of calcium and phosphate. This is consistent with research findings that CPP-ACP can increase the pH of saliva [35]. Consistent with the results of tests in children 8–10 years of age, it was found that after chewing the CPP-ACP chewing gum, the saliva pH immediately increased and increased dramatically in 15 minutes [34].

6. Chewing gum and tooth strengthening

In this regard, the physical appearance of chewing gum has no effect, but with the properties of compounds that are beneficial to oral health, such as xylitol and CPP-ACP, chewing gum containing such compounds has outstanding features in promoting oral health, as follows:

Although xylitol is not very prominent in its remineralization, it does so as xylitol prevents enamel resorption by inhibiting the migration of calcium ions and phosphate ions from the lesions. Xylitol acts as a carrier of calcium ions to the tooth, especially in areas of demineralization. It accelerates the remineralization of the tooth. This mechanism increases the strength of the tooth [11].

CPP-ACP is the most outstanding tooth remineralization agent. CPPs consist of a multiphosphoseryl sequence, which can stabilize calcium phosphate in ACP solution within a nano complex solution. CPP-APP nanoscale complex molecules bind to the tooth surface. It prevents demineralization and can induce remineralization in enamel subsurface lesions. The hardness of the tooth will be more CPP-ACP binds with fluoride ions (F⁻) to form amorphous calcium fluoride phosphate (ACFP) and stabilizes with CPP at the tooth surface, where these substances can diffuse into the lesion area. Calcium phosphate and fluoride solutions can help speed up the remineralization process with fluorapatite (Ca₅(PO₄)₃F₂), which resists acidic conditions and can penetrate deep into the lesion of the tooth (Figure 7). The advantage of being able to penetrate into the lesion is the ability to restore opaque enamel or white spot lesion [36]. It was also reported that CPP-ACP promoted the efficiency of fluoride use. This is caused by combining fluoride ions with ACP to make ACFP at the enamel surface. Based on these findings, CPP-ACP helps fluoride adhere to the tooth surface and enhances anti-demineralization efficiency [37], which has been shown to increase the effectiveness of fluoride in preventing tooth decay [38].

Figure 7.

Remineralization mechanism of CPP-ACP with fluoride.

7. Conclusion

Dental caries is generally caused by four factors: the tooth, diet, bacteria, and acid exposure time. Therefore, methods for preventing tooth decay must properly control those four factors. Sugar-free chewing gum has both physical and chemical properties to prevent tooth decay. The physical property of chewing gum is the direct attachment of the gum to food particles in conjunction with increased chewing and saliva. Increasing saliva can help wash away food particles and chemical properties from betel nut constituents such as xylitol and CPP-ACP. These compounds reduce oral bacteria, improve oral hygiene, and strengthen tooth enamel. The properties mentioned earlier of sugar-free chewing gum were able to control the four causative factors of caries incidence. Therefore, it was concluded that sugar-free chewing gum had caries-prevention properties. Additionally, sugar-free chewing gums are easily accessible, can be chewed in any situation, whether on-site or off-site, and are popular with school-age children, teens, and adults. Therefore, chewing gum, although not as effective as brushing or flossing, is another way to clean your mouth and control cavities.

Conflict of interest

The authors declare no conflict of interest.