Two independent reviewers conducted a systematic search of English-language articles published in peer-reviewed journals between 2006 and 2023. The search was performed from December 2, 2018, to September 8, 2023, across PubMed, Scopus, and Google Scholar. Search terms included “Punica granatum” [MeSH], “dental caries” [MeSH], “Streptococcus mutans” [MeSH], and “tooth demineralization” [MeSH]. The initial search results were compiled into an abstract database focusing on studies examining the effects of Punica granatum on dental caries. The search strategy outcomes are summarized in Table 1.

fter the initial literature search, abstracts were screened for consistency with the PICOS (Population, Intervention, Comparison, Outcomes, Study design) objectives. Studies that did not address the primary research questions of this systematic review were excluded.

Articles selected for full-text review were entered into an Excel spreadsheet, and the two reviewers assessed agreement on inclusion. The final selection was based on a full-text review, with study quality and risk of bias evaluated using the Cochrane Collaboration's tool.

This study prioritized in vitro and in vivo research using dental models (human or bovine tooth fragments) and interventions involving Punica granatum extract. Additional relevant studies were identified through snowball sampling (citation tracking of reference lists in selected articles) and included if they met the primary and secondary search criteria.

Following the final review, the reviewers summarized the findings, identified key themes, and reached a consensus on the reported outcomes.

The results of the evaluated studies are summarized in Table 2. Initial database searches using predefined keywords yielded 83 articles from Scopus, 24 from PubMed, 150 from Google Scholar, and 31 from the CENTRAL (Cochrane Central Register of Controlled Trials) database. After removing duplicates using EndNote X9, 182 articles remained. Two reviewers independently conducted title/abstract and full-text screening. Ultimately, six articles that evaluated the effect of Punica granatum on dental caries met the inclusion criteria (Figure 1). The included studies assessed outcomes such as tooth demineralization, Streptococcus mutans count, and dental caries.

The risk of bias in this review article was examined using the Cochrane Risk of Bias assessment tool. Three of these articles had a high-risk bias for criteria of detection bias (34–36), and 3 had an unclear risk for selection bias (35, 37, 38). Four of them had an unclear risk for attrition bias (34, 35, 37, 38), and two had an unclear risk for performance bias (36, 37). Figure 2 summarizes the evaluation bias risk of the included articles.

Among seven articles, 4 were performed in India (34, 35, 37, 38), 1 in Brazil (39), and 2 in Egypt (36, 40). All of the studies were randomized clinical trials (34–40).

In four of them, participants were children (35–37), and in 2 articles, adults were evaluated (34, 35, 37–40). Finally, 1 article included participants with a wide age range from 9 to 50 years (39).

All seven studies used pomegranate mouthwash as the intervention. Preparation methods varied by plant part (peel, juice, or whole fruit), solvent, and technique. Peel extracts were most common. Kadam et al. (38) sun- and oven-dried the peel, powdered it, and used aqueous Soxhlet extraction. Bansal et al. (37) and Mishra et al. (35) also used peel extracts but did not describe methods. Whole fruit extracts were used by El Naggar et al. (40) and Menezes et al. (39) Juice and peel extracts were used by Ibrahim et al. (36), juice was hand-extracted and concentrated by heating; peel was air-dried, pulverized, mixed with water, and filtered. Srilekha et al. (34) used a commercial product with unspecified extraction details.

In six studies, control groups used 0.2% chlorhexidine (CHX) mouthwash (34–38, 40). Among these, three also included other mouthwashes in their experimental groups: Mishra et al. (35) used Terminalia chebula and Vitis vinifera extracts; Bansal et al. (37) included 10% Achyranthes aspera; and El Naggar et al. (40) evaluated saline alongside CHX. Only one study did not use CHX; instead, the control group received distilled water (39).

Seven studies evaluated the effects of Punica granatum (pomegranate) mouthwash on oral health outcomes, including antibacterial efficacy, salivary pH, enzymatic activity, and plaque index. Five studies (34–37, 39) reported a reduction in S. mutans count following pomegranate mouthwash use. In Bansal et al. (37), P. granatum, CHX, and A. aspera mouthwashes significantly reduced both plaque index and S. mutans count after seven days, though CHX showed the greatest effect. Mishra et al. (35) found pomegranate mouthwash produced the largest decrease in S. mutans compared to T. chebula, V. vinifera, and CHX, although pH and buffering capacity did not differ significantly between groups. Their findings suggest P. granatum's preventive effect may involve inhibiting hydrolytic enzymes or interfering with bacterial adhesion to teeth.

El Naggar et al. (40) compared the effects of saline (control), CHX, pomegranate, and propolis mouthwashes. All groups showed an immediate rise in salivary pH post-use, with no significant differences between groups. After seven days, pH significantly declined in the pomegranate and propolis groups, while no change was observed in the CHX and saline groups. Bacterial counts were similar across all groups. This study noted that pomegranate mouthwash reduced alpha-glucosidase activity and increased ceruloplasmin, an antioxidant enzyme.

Menezes et al. (39) demonstrated that a hydroalcoholic pomegranate extract exhibited strong antibacterial activity against dental plaque microorganisms. It reduced CFU/ml by 84%, outperforming CHX (79%) and distilled water (11%). Similarly, Ibrahim et al. (36) found that pomegranate mouthwash led to a significant reduction in S. mutans count in children, with the greatest antibacterial effect observed in the pomegranate group compared to other treatments, such as CHX.

Finally, Srilekha et al. (34) assessed S. mutans counts after immediate and seven-day use of CHX and pomegranate mouthwash. Both groups showed significant reductions at day seven compared to baseline, with no significant difference between them. They also reported that pomegranate's effects were linked to reduced alpha-glucosidase activity and enhanced ceruloplasmin levels. Participants in this study had fair-to-good plaque index scores. Kadam et al. (38) also reported that pomegranate peel extract mouthwash significantly increased salivary pH and decreased salivary alpha-glucosidase activity, an enzyme that breaks down sucrose, while also enhancing ceruloplasmin activity, an antioxidant enzyme. The authors concluded that pomegranate mouthwash may have protective effects against dental caries by influencing these enzymatic activities.

CHX mouthwash is commonly prescribed as the gold standard for preventing plaque formation and gingivitis. However, long-term use of CHX is associated with several side effects. Commonly reported effects include taste alteration, oral numbness, dry mouth (xerostomia), and discoloration of the tongue and teeth, with tooth staining being the most frequent reason for discontinuation (41). Other long-term effects may include calculus accumulation, oral paraesthesia, mucosal desquamation, and, in rare cases, parotid gland swelling (42). Additionally, concerns have arisen regarding antimicrobial resistance, particularly with ESKAPE pathogens, following repeated low-level exposure to CHX (43).

Punica granatum mouthwash did not cause taste changes compared to CHX (40). None of the studies reported adverse events associated with Punica granatum mouthwash. A potential limitation in the reviewed studies is the inadequate reporting of adverse events. Most trials did not specify whether adverse effects were actively monitored, and none used standardized tools for adverse event assessment. Short follow-up durations, especially in studies with outcomes measured within minutes to a few days, may have further limited the detection of delayed or mild side effects.

The antimicrobial effect of P. granatum is primarily attributed to its polyphenols. These polyphenols may affect bacterial cell walls, discourage microbial coaggregation, and inhibit bacterial enzymes through oxidation (44). The bioactivity of pomegranate extract is largely due to its high content of ellagitannins, particularly punicalagin. Punicalagin modulates oxidative stress by scavenging free radicals and inducing cellular antioxidant defenses, such as upregulation of superoxide dismutase and glutathione peroxidase, while suppressing pro-inflammatory cytokines like IL-6 and TNF-α (45, 46). A study by Scaglione et al. (47) found that pomegranate peel extract (PPE) exhibited antimicrobial activities without inducing ROS production or cytotoxicity in human cell lines after 30 h, supporting its selective bioactivity and low toxicity in primary cells and macrophage models (48). Furthermore, the depletion of punicalagin and related compounds during bacterial incubation, as observed by Peppoloni et al. (49) suggests active interaction with microbial targets, likely through membrane disruption, enzyme inhibition, and interference with quorum sensing, as proposed in studies of polyphenol–pathogen dynamics (50).

In addition to S. mutans, dental plaque harbors over 400 distinct bacterial species that digest carbohydrates, produce acid, and contribute to the development of dental caries. These microorganisms can be broadly categorized based on oxygen tolerance, Gram staining characteristics, and morphology (51): •

Gram-positive aerobes: S. sanguis, S. sobrinus, S. salivarius, Actinomyces viscosus

Saliva's pH and buffering capacity are critical in determining the risk of dental caries. Acidic pH promotes enamel demineralization, increasing the risk of caries (52). This review found that Punica granatum mouthwash increases salivary pH.

However, the comparative effectiveness of Punica granatum relative to chlorhexidine (CHX) remains inconclusive. In a study by El Naggar et al. (40), CHX use over 7 days resulted in a significantly greater increase in salivary pH compared to Punica granatum mouthwash, indicating superior efficacy. In contrast, findings from Mishra et al. (35) and Kadam et al. (38) showed no statistically significant difference between the two interventions, suggesting comparable outcomes.

The time frame in which Punica granatum mouthwash affects salivary pH varies widely across studies, ranging from immediate effects to 15 days. Even a single use of Punica granatum mouthwash has been shown to significantly increase salivary pH (40). However, comparisons between studies are difficult due to differences in factors such as mouthwash concentration, formulation type (aqueous or hydroalcoholic), and frequency of use. Therefore, while Punica granatum shows promise in increasing salivary pH, further studies are needed to determine whether it consistently matches the effectiveness of CHX.

Furthermore, only two studies explicitly showed the Punica granatum mouthwash decreased the plaque index with the same efficacy as CHX (35, 37). In terms of S. mutans reduction in dental plaque, theree of the included studies reported similar antimicrobial efficacy between P. granatum and CHX (34, 39, 40) although the aqueous extract used in Menezes et al. (39), was less effective than the hydroalcoholic version and CHX. One study found CHX to be marginally more effective than P. granatum (37), while Ibrahim et al. (36) reported greater bacterial reduction with P. granatum than CHX.

It has been suggested that P. granatum reduces dental plaque by inhibiting the bacteria responsible for its formation. Tannins such as punicalin and punicafolin, found in pomegranate peel, inhibit human salivary alpha-amylase, an enzyme that facilitates plaque formation by providing substrates for cariogenic bacteria. Alpha-amylase catalyzes the hydrolysis of starch to produce oligosaccharides, which bind to both enamel and cariogenic bacteria, promoting plaque formation. By preventing bacterial adhesion to enamel, P. granatum helps reduce plaque formation (53, 54).

Most of the reviewed studies involved healthy children and young adults aged 6–15 years. Only two studies assessed the efficacy of Punica granatum mouthwash in individuals at high caries risk: one focused on 9–25-year-olds using fixed orthodontic appliances (39), and the other included 17–50-year-olds with high caries risk based on the ADA caries risk assessment (40).

The studies used various parts of Punica granatum, including seeds (38), fruit (34), peel (37), arils, exocarp, and mesocarp (40). Only one study extracted a hydroalcoholic solution directly from Punica granatum and evaluated its effect on S. mutans levels in dental plaque (39). Therefore, it remains unclear which specific component of Punica granatum is responsible for its antibacterial effects against S. mutans.

Compared to a previous systematic review evaluating the efficacy of pomegranate-based products in oral health, the systematic review and meta-analysis by Javan et al. (55) examined the effects of pomegranate vs. CHX on periodontal indices such as plaque index, gingival index (GI), and bleeding index (BI). Their results showed that while CHX had a significantly greater impact on plaque reduction at 14–15 days, no significant differences were found in shorter durations or for GI and BI, suggesting comparable anti-inflammatory effects between Punica granatum and CHX in periodontal contexts. similarly in our review, while most included studies also reported CHX to be more effective, at least one study demonstrated superior efficacy of hydroalcoholic pomegranate extract, and none reported adverse effects with Punica granatum use. Thus, both reviews highlight the antimicrobial and anti-inflammatory potential of pomegranate. In conclusion, our findings from the reviewed studies showed that Punica granatum mouthwash has antimicrobial potential compared to CHX mouthwash without any reported side effects. This mouthwash might be beneficial in preventing dental caries by decreasing the plaque index, increasing salivary pH, and reducing the levels of S. mutans in saliva and dental plaques. Such mouthwash would be less costly and well tolerated by patients.

Nevertheless, this systematic review has several limitations that should be taken into account when interpreting the results. First, the number of available studies on Punica granatum mouthwash was limited, and most had relatively small sample sizes. There was also considerable variation among the studies in terms of the type of formulation used (aqueous vs. hydroalcoholic), the concentration of P. granatum extract, the duration and frequency of use, and the specific plant parts used (peel, seeds, fruit, or whole fruit components). Additionally, only a few studies investigated the antimicrobial activity of P. granatum against a broader range of oral bacteria beyond S. mutans, despite the fact that dental plaque contains a diverse bacterial population. The follow-up periods were generally short—ranging from a single application to just a few days—which limits the understanding of the mouthwash's long-term effectiveness and safety. While no adverse effects were reported, most studies did not clearly describe how adverse events were monitored, raising the possibility of underreporting. These limitations highlight the need for larger, well-designed clinical trials using standardized mouthwash formulations, longer follow-up durations, broader microbial assessments, and more rigorous safety reporting.