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INTRODUCTION

The human oral cavity is a complex system that harbors a wide variety of bacterial species. An increased incidence of microbial populations can easily be impaired, and the proliferation of pathogenic organisms can be the initiation or progression of stomatology diseases (1).

Currently, scientific studies have shown that a homeostasis between non-pathogenic bacteria and the bacteria that cause the diseases is a determining factor for oral health. For example, the appearance of caries reduces the balance within the oral cavity, i.e., there is a greater number of cariogenic agents such as streptococci, lactobacilli, actinomyces, bacteroides and bifidobacteria (2, 3). Therefore, the ingestion of foods containing probiotics has been proposed as preventive adjuvants or for the treatment of dental diseases such as caries, gingivitis, and periodontitis, thus restoring the balance of the microflora (4). In addition to the above, the use of probiotics in the treatment of periodontal disease has been proposed as a preventive adjuvant for the treatment of tooth decay (4, 5).

Dental caries and periodontal disease are the most common oral diseases worldwide within the field of dentistry and require treatment due to their high incidence, being usually as first alternative the prescription of antimicrobial drugs achieving to restore a healthy microbiome; however, it can cause gastrointestinal adverse effects because of broad-spectrum antibiotics, bacterial resistance, and possible allergic reactions (5). Consequently, the consumption of probiotics has been considered to have preventive and therapeutic effects, making it a non-invasive option for the control of carious and periodontal disease (6). On the other hand, Lactobacillus albicans is an effective treatment for caries and periodontal disease.

On the other hand, Lactobacillus and bifidobacterium are the most used probiotics against oral cavity alterations, these strains present a balanced immune function, a healthy intestinal microbiome and better absorption of nutrients, therefore, leading to a healthy host. It has been demonstrated that the consumption of fruit juice has a positive effect in the control of caries and periodontal disease (7,8). It has been shown that the consumption of probiotics presents preventive and therapeutic effects.

Fruit juice, cheese, yogurt, and fermented milk, as well as their inclusion as a component in tablets and capsules, have been shown to have beneficial effects on oral tissues by reducing the incidence of caries, halitosis, periodontitis, and oral thrush (9).

Thus, the present literature review aimed to describe the uses and applications of probiotics in dentistry.

MATERIALS AND METHODS

Search strategy

For the recognition of the studies, a search without date restrictions was carried out in the online database of scientific literature research in medical and biological sciences, accessed through PubMed and Scopus.

The following search terms were used, which were adapted for each database, respectively: ("probiotic s"[All Fields] OR "probiotical"[All Fields] OR "probiotics"[MeSH Terms] OR "probiotics"[All Fields] OR "probiotic"[All Fields]) AND ("dentistry"[MeSH Terms] OR "dentistry"[All Fields] OR "dentistry s"[All Fields]).

Inclusion criteria

The present study searched for randomized controlled trial type articles concerning the use of probiotics in dentistry for plaque reduction. The search was limited to research articles published in the English language.

Exclusion criteria

Clinical case studies on the use of probiotics were not included in the present research. Likewise, articles that were not found in PubMed, Scopus and are in any language other than English were excluded.

Risk-of-bias assessment

Because the study is only a literature review, it is not intended to evaluate the potential risk of bias, nor does it perform a systematized search for information.

RESULTS

Significant studies related to the level of efficacy of probiotics were obtained from the searches performed. Ten studies investigating their capacity as adjuvants during cariogenic or preventive treatments were considered for the present review. Details of the reviewed studies are shown according to their objective, population, study method and conclusion.

The characteristics of the 10 selected articles (10-19) were randomized clinical trial design (RCT) from the last 5 years (2018-2023). The probiotic strains studied in different presentations such as tablets, yogurt, probiotic-based mouthwashes, drops; were W. cibaria CMU, L.rhamnosus SP1, B. lactis HN19, L. reuteri, L. acidophilus La5 and B. lactis Bb12 to know their effect in different types of populations to preserve oral health. Also, patients suffering from oral diseases such as periodontitis or undergoing orthodontic treatment were included in certain studies (Table 1).

ORAL MICROBIOME

The microbiome of the oral cavity determines the oral health conditions of the patient. However, when there is an imbalance, the bacterial plaque located in the mouth produces dysbiosis and these bacteria are responsible for the formation of oral diseases (20).

The oral microbiome is composed of a community of microorganisms that are organized in biofilms. These biofilms are polymicrobial communities that are complex in both structure and function and are embedded in an extracellular matrix and attached to the hard and soft tissues of the oral mucosa. The formation of pathogenic biofilms can trigger the onset and progression of dental diseases such as caries, gingivitis, periodontitis and peri-implantitis (21, 22).

BIOFILM AND ORAL DISEASES

Biofilm organization varies in different areas of the oral cavity due to variations in ecological niches. In the supragingival zone, the dominant species include facultatively anaerobic saccharolytic anaerobic organisms of the genera Actinomyces, Veillonellag, Granulicatella, Streptococcus, and Rothia, whereas in the subgingival zone, gram-negative, anaerobic, and proteolytic species are found (23, 24). In the subgingival zone, gram-negative, anaerobic, and proteolytic species are found. In the subgingival zone, the organisms are found to be anaerobic and proteolytic.

It has been observed that the organisms of the biofilm precede the presence of a layer of macromolecules. This layer was initially thought to primarily originate from salivary glycoproteins. However, a recent study has indicated a significant contribution from gingival crevicular fluid in the formation of this layer (25).

Probiotics

Several studies have shown that probiotics are live microorganisms that confer advantages in maintaining or improving host health when administered in adequate amounts. For example, one of the contributions of probiotic consumption is that they can stop periodontal bacterial plaque and regulate the host's immune response (26, 27). Therefore, they can help to better control biofilm, reverse dysbiosis and even decrease periodontal inflammation (28).

Probiotics and prevention of dental caries

There are several predisposing factors in the manifestation and proliferation of carious processes such as changes in diet, poor oral hygiene methods, consumption of medications that can alter salivary flow and variations in immune response (29). Consequently, it leads to the appearance of S. mutans, the most common bacterial microorganism responsible for the demineralization of dental enamel and the onset of a carious process (30). Probiotics for periodontal health and the prevention of periodontal caries.

Probiotics for periodontal health

Chronic periodontitis is considered a predominant polymicrobial disease and represents an inflammatory process where there is involvement of the soft and hard tissues of the teeth such as the gingiva, periodontal ligament. However, it is associated with other changes at the systemic level when left untreated (24). The strains such as Lactobaccus and Lactobacterium spp.

Strains such as Lactobaccillus and Bifidobacterium have been characterized by their ability to alter periodontal biofilm. In studies testing Bifidobacterium animalis, a reduction in biofilm virulence was observed, such as gingival inflammation, and an improvement in the pathogenic bacteria of periodontal diseases (32-34). The results of these studies show that Bifidobacterium animalis is associated with a reduction in the virulence of the biofilm as gingival inflammation and an amelioration of pathogenic bacteria for periodontal disease.

Probiotics in relation to halitosis

Halitosis is a problem that can have a negative impact on the social and professional life and quality of life of people who suffer from it due to the unpleasant odor that comes from the breath (35). The causes of this problem can vary and may be related to factors such as diet, poor oral hygiene, diseases with periodontal involvement, ulcers, lack of salivary flow, use of prostheses, consumption of toxic substances such as alcohol, tobacco, among others (36). For a better control of halitosis, the patient should undergo certain treatments or change of habits, including the use of mouthwashes, periodontal treatment, implementation of periodontal treatment, and the implementation of probiotics.

For better control of halitosis, the patient should undergo certain treatments or change of habits, including the use of mouthwashes, periodontal treatment, implementation of supplements such as interdental brushes for better hygiene and cleaning of the tongue coating. In addition, various resources, such as the use of probiotics, can be employed to combat halitosis (37). Several investigations have shown that strains of Lactobacillus, which are active ingredients in probiotics, can be effective in combating bad breath (38).

Probiotics and orthodontics

Previous studies have found that increased numbers of Streptococcus mutans are considered a major risk factor for dental caries and have been linked to the placement of fixed orthodontic appliances (39). In the field of dentistry, patients receiving orthodontic treatment or wearing fixed prostheses on dental implants rely more on chemical or probiotic cleaning to remove bacterial plaque than physical removal by brushing or rinsing the mouth (40).

PROBIOTIC ACTION IN THE ORAL CAVITY

Microorganisms inhabiting the oral cavity are grouped in biofilms and perform various functions such as regulating homeostasis, immunity, digestion, and detoxification. Despite this, there are probiotics that help maintain oral health (41). In an in vitro study, postbiotic lactic acid bacteria were shown to reduce colonization of A. actinomycetemcomitans, which is associated with periodontal disease (42). Other studies indicate that topical use of the probiotic strain Bifidobacterium lactis HN019 protects against alveolar bone loss and connective tissue attachment loss attributable to periodontitis (43). Besides, the use of this strain in conjunction with periodontitis treatment has been shown to provide additional clinical improvements, such as decreased probing pocket depth, clinical attachment gain, and reduced bleeding on probing (16). In addition, the use of this strain in conjunction with periodontitis treatment has been shown to provide additional clinical improvements, such as decreased probing pocket depth, clinical attachment gain, and reduced bleeding on probing.

PROBIOTIC AND CHEMICAL-BASED RINSES

Mouthwashes such as chlorhexidine are very popular due to their effectiveness. However, adverse effects associated with its use have led to the consideration of other products to inhibit Streptococcus mutans activity (44). On the other hand, studies have been conducted on a probiotic mouthwash containing Lactobacillus salivarius and Lactobacillus reuteri to evaluate its effect in patients with periodontitis. The results indicate that the use of this mouthrinse together with a plaque and calculus removal technique for a period of 15 days can significantly reduce the plaque index, which promotes oral health. The results indicate that the use of this mouth rinse together with a plaque and calculus removal technique for a period of 15 days can significantly reduce the plaque index, which supports oral health (45).

DISCUSSION

Microbes could generate chemicals like hydrogen peroxide, bacteriocins, and organic acids that possess defined bactericidal properties. These substances act on adhesion sites in the mucosa through competitive inhibition, preventing the proliferation of harmful microorganisms. Therefore, there are changes in pH and alter the ability of microorganisms to achieve oral homeostasis. In addition, probiotics trigger non-specific immunity in individuals and alter their cellular and humoral immune mechanisms. Lactogenic bacteria can exert their modulatory influence on immunocompetent cells, such as T cells and macrophages. As a result, they can impair cytokine production in these cells and influence the individual’s overall immune response. It is worth mentioning that the addition of probiotic strains produces a synergistic effect, i.e., it has greater beneficial effects than individually (46).

The consumption of probiotics in dentistry is a subject of current research as they may succeed in producing changes in the oral microbiota and may contribute to ensure proper physiological function by acting as a preventive method for caries and periodontal disease (47). Nowadays, probiotics found in daily consumption such as yogurt, cheese are the third most consumed dietary supplement after vitamins and minerals (48). In addition, they are characterized by being able to integrate with other agents of the oral biofilm and favor the growth of other acidogenic bacteria (49).

Various etiologic factors such as smoking, type of diet and poor oral hygiene contribute to a progressive development of parts of the microbiota at the expense of others (50-52). Bacterial therapy or replacement therapy is a very effective way to prevent the development of microbiota in the oral cavity.

Bacterial therapy is a treatment that employs harmless bacteria as opposed to pathogenic bacteria to treat disease. Thanks to the characteristics and beneficial effects they confer, such as caries treatment, halitosis, and the onset of gingival disease, probiotics are added in mouthwashes and toothpastes. As a result, probiotics are truly new and innovative agents that can be used to treat a variety of oral diseases (53). In addition, probiotics can be used to treat a wide range of oral diseases.

The consumption of probiotics added to the diet for therapeutic purposes as an adjuvant in oral health care has grown significantly in the last decade. Several studies have shown that the intake of probiotics as a complement to an optimal diet and dental hygiene promotes clinical and microbiological benefits during the treatment of caries, gingivitis, chronic periodontitis in different age groups. The consumption of probiotics in the treatment of caries, gingivitis, and chronic periodontitis in different age groups has been shown to be beneficial (16,17,19).

Therefore, it is considered that the pathogenic bacteria originating in the mouth because of multiple factors previously mentioned, will encourage alterations in the intestinal microbiota, and therefore can cause inflammation and changes in the system. This is why it is convenient to have a microbiota in homeostasis that achieves benefits in the patient (54,55). In particular, the continuous consumption of probiotics and probiotics in the intestinal microbiota should be avoided.

The continued consumption of probiotics for caries prevention produces an inhibitory effect on bacterial proliferation and reduction of bacterial adhesion to tooth surfaces. Also, a decrease in the acidogenicity of plaque and reversal of caries lesions at the root level (56,57). In addition, a decrease in the acidogenicity of plaque and a reversal of caries lesions at the root level.

Non-surgical periodontal treatments such as scaling and root planing for people with periodontal disease have been studied so that the usefulness of probiotics can be applied as a complementary therapy. Several studies have found positive results such as a decrease in periodontal pathogens and in turn a clinical improvement of the patient (58). It has been described that the therapeutic intake of Limosyloactobacillus [L.] reuteri led to clinical improvements in pregnant patients who are at risk population for acquiring gingival and/or periodontal disease Probiotic bacteria that have been used in the treatment of periodontal disease have been shown to be effective in the treatment of periodontal disease in pregnant women (59).

Probiotic bacteria that have been the subject of study such as "Lactobacilli and Bifidobacterium" as they are able to survive in acidic environments such as carious lesions. This is due to their ability to regulate their pH in the face of extracellular acidification. Additionally, they display a high level of resistance in their cell membranes and possess the capability to produce intracellular alkalis, allowing them to survive (60).

It is important to note that, in the various studies previously described, different vehicles have been used such as chewing gum, lozenges, among others; and each of them is going to have a more potent effect than another probably, therefore, suggesting different washout times. For example, in one study, participants who consumed probiotic ice cream evidenced a decrease in S. mutans as opposed to a probiotic beverage after a three month washout period (61). In another study, participants ingested probiotic curd, so gradual recolonization was observed after a 14-day washout period (62). In the clinical cases analyzed, the use of probiotics has been shown to be more effective than the use of a probiotic beverage (63). In the clinical cases analyzed, the use of a probiotic beverage has been shown to be more effective than a probiotic beverage.

In the clinical cases analyzed they have used different types of "vehicles" containing the probiotics such as tablets, drops and yogurt. Despite this, it is still not possible to decipher which is the most suitable vehicle for the administration of probiotics for children, youth and elderly and if they are undergoing any treatment plan such as orthodontics it may influence a prevalence of bacterial plaque (10,17). The use of probiotics in children, youth and the elderly is not yet clear.

Among the limitations to produce this literature review is that the clinical studies were mainly based on the probiotic action of Lactobacillus and Bifidubacterium, which restricts a broader vision for the knowledge of other types of probiotics. Likewise, some of the selected studies had a short-term follow-up period and small sample size. On the other hand, most of these articles are based on diseases such as caries and periodontitis, when it is necessary to know if probiotics have a favorable effect on other oral diseases.

The strengths and importance of this research study is that it encourages the production of more trials to determine with greater certainty the benefits of the daily consumption of probiotics. Because of this research topic, it could be of great help in preventive dentistry in the entire population.

CONCLUSION

Within the limitations of this literature review and based on the evidence consulted, the most tested and studied strains were Lactobaccillus and Bifidobacterium, most of which showed positive effects in the reduction of bacterial plaque such as S. mutans in pediatric, adult, and geriatric patients. Additionally, their efficacy was compared with mouthwashes based on probiotics, which also showed biofilm reduction. Therefore, it serves as a coadjutant in the established oral hygiene of the patient and the consumption of a balanced diet free of sugars. In summary, there is a large production of studies on the application of probiotics in dentistry. However, it is necessary to carry out more robust studies with other types of bacteria, different vehicles, and long-term follow-up to determine with greater precision which species help to maintain oral health and at the same time to observe the statistical significance of probiotic action against oral diseases.

CONFLICTS OF INTEREST

There are no conflicts of interest.

AUTHOR CONTRIBUTIONS STATEMENT

Conceived the ideas: S.C., S.G. and F.M.T.

Contributed to data collection: F.E.C.; R.M. and F.M.T.

Analyzed the data: S.C., S.G., F.M. and F.M.T.

Led the writing: F.M.T.

All authors critically revised the manuscript and gave final approval.

ACKNOWLEDGEMENTS

The authors would like to thank the Universidad Nacional Federico Villareal for providing us with all the support during the preparation of this literature review.

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