1. Introduction

Oral hygiene is a critical aspect of maintaining overall health and well-being, as it directly influences the integrity of the oral cavity and has far-reaching implications for systemic health [1]. Conventional oral hygiene measures, such as toothbrushing, flossing, and mouth rinsing, have long been advocated as essential practices to maintain optimal oral health [2, 3].

The use of organic resources as medicines has been reported in the form of traditional drugs, therapies, potions, and oils. Most of them contain bioactive natural substances that remain unidentified [4]. Exploring natural products and alternative methods to improve oral hygiene has gained popularity in recent years. Herbal products have been utilized to prevent diseases and enhance well-being since ancient times [5, 6]. Naturally derived compounds possess diverse chemical structures with high biochemical specificity and favorable molecular properties that are desirable for drug discovery and development [7]. The majority of these compounds are plant-based secondary metabolites, such as flavonoids, phenolic acids, tannins, anthraquinones, alkaloids, terpenoids, and stilbenes. These compounds effectively inhibit the growth of pathogenic microorganisms [8, 9]. One such alternative is to employ Salvadora persica, commonly known as miswak, a traditional oral hygiene tool with a rich historical and cultural background. The practice of using chewing sticks derived from this plant for oral hygiene is widely recognized in traditional Arabic culture [10]. For about seven thousand years, the Babylonians instigated the use of these chewing sticks for dental hygiene. This practice spread to various cultures including Egypt, Rome, Greece, and the Islamic kingdoms, and persists in many regions globally, notably in Asia, Africa, South America, and the Middle East countries such as Saudi Arabia and other Islamic countries [11]. The World Health Organization has recommended and endorsed the use of chewing sticks made from S. persica as an effective tool for oral hygiene in regions where this practice is customary [12].

Salvadora persica L (“toothbrush tree”), which is a Salvadoraceae family member, is widely used in many Middle Eastern, Asian, and African countries [13], as chewing sticks, to maintain oral hygiene [14]. Miswak has its special features for use, wherein a thin piece of bark is stripped off at the useful end and then chewed. When miswak is chewed, fibers are frayed, giving it a brush-like look that makes it easier to clean teeth [15]. The mechanical cleansing action of miswak contributes to its oral hygiene benefits. The natural bristles of the miswak stick help remove food debris, stains, and plaque from the teeth, promoting oral cleanliness [16].

The antimicrobial activity of miswak has been extensively studied and attributed to its active constituents, including alkaloids, flavonoids, and essential oils. According to the reviews, the extract of Salvadora persica contains a wide range of organic (such as saponins, glycoside, alkaloids, benzyl derivatives, flavonoids, tannins, phenolic compounds, and organic acids) and inorganic substances (such as chloride, fluoride, thiocyanate, nitrate, and sulfate) [17]. Miswak possesses the ability to impede the growth of microbes that cause periodontal disease [18–22]. Previous literature reports that miswak has significant antimicrobial activity against Actinobacillus, Streptococcus mutans, Porphyromonas gingivalis, Enterococcus faecalis, Haemophilus influenza, and to a lesser extent, against Lactobacillus species [23]. Sofrata et al. in 2011 identified benzyl isothiocyanate in the extracts of Salvadora persica and demonstrated its rapid and potent bactericidal effect against Gram-negative bacteria [24].

While conventional oral hygiene measures such as tooth brushing and flossing are widely practiced, miswak as an alternative oral hygiene tool has gained attention due to its natural origin and potential additional benefits [25]. Aqueous miswak extract demonstrated antimicrobial effects, in in vitro studies, against specific oral bacteria, such as S. mutans, Staphylococcus aureus, and anaerobic species of Streptococcus, with growth inhibition levels depending on the concentration of the extract [26, 27].

With growing interest in natural alternatives, it is important to compare the efficacy and advantages of miswak with conventional oral hygiene measures to provide evidence-based recommendations for individuals seeking alternative oral hygiene options. The following systematic review is conducted to determine the efficacy of miswak (in all forms) to be used as an alternative and/or adjunct to the oral hygiene practices that are followed daily. Therefore, this systematic review aims to assess the antibiofilm properties of miswak (Salvadora persica) in comparison with conventional oral health measures in adult permanent teeth. Based on the PICOS (Population, Intervention, Comparison, and Outcome, Study design) strategy, the research question was formulated [28]: In randomized controlled trials (RCTs) (S) involving adult patients (P), is the use of miswak (Salvadora persica) (I) superior to or comparable with conventional oral health measures (C) in terms of antibiofilm activity (O)?

2. Materials and Methods

3. Results

3.1. Study Selection

Figure 1 illustrates the outcomes of the search strategy. 474 potentially eligible articles have been identified published from inception till July 31, 2023. The distribution of results across the five databases is as follows: PubMed (74), Scopus (248), Web of Science (116), ProQuest [27], and Cochrane Central Register of Controlled Trials [5], and 4 studies retrieved from the trial registry (clinicaltrials.gov). 277 of these were eliminated as duplicates. The remaining 197 articles were assessed based on their titles and abstracts. After the titles and abstracts were evaluated, 184 articles were eliminated as they did not meet the predetermined inclusion criteria. The 13 remaining papers were thoroughly examined in their entirety in order to ensure that they met the preset inclusion requirements. As a result, three studies that did not fit the inclusion criteria have been eliminated. The reasons for exclusion are listed in Table 2. Overall, 10 studies were considered for the qualitative analysis. The kappa coefficient revealed a 100% agreement between the reviewers in their assessment including search strategy, screening, and data extraction of the included articles. A meta-analysis could not be performed for this systematic review due to critical limitations related to methodological variability and data heterogeneity. The differences in sample size, intervention protocols, outcome measures, and follow-up periods account for significant heterogeneity and lack of standardization that prevents meaningful statistical pooling of data. Several studies provided insufficient statistical data, making data extraction for meta-analysis unfeasible.

Table 2. Excluded studies.

Title of the study	Authors	Year of publication	Reason for exclusion
Comparative Effectiveness of Chewing Stick and Toothbrush: A Randomized Clinical Trial	Aeeza S. Malik, Malik S. Shaukat, Ambrina A. Qureshi, Rasheed Abdur	2014	Neem was used instead of miswak as a primary intervention.
Comparison of Fluoridated Miswak and Toothbrushing With Fluoridated Toothpaste on Plaque Removal and Fluoride Release	Hosam Baeshen, Sabin Salahuddin, Robel Dam, Khalid H. Zawawi, Dowen Birkhed	2017	The concentration of fluoride alone was assessed.
Distribution of Dental Plaque and Gingivitis Within the Dental Arches	Prem K. Sreenivasan and Kakarla V. V. Prasad	2017	Miswak was not used as an intervention.

3.7. Risk of Bias Assessment

Figures 2 and 3 summarize the risk of bias assessment of the included studies. Four studies satisfy the majority of domains of risk assessment, suggesting a low risk of bias. The majority of studies report unclear risk with attrition and reporting bias.

4. Discussion

With the evolution of dentistry, the emphasis is shifting increasingly toward preventive procedures that focus on the root causes of oral disease [41]. Throughout history, natural remedies have been integral to traditional medicine. Within dentistry, phytomedicines have gained extensive utilization. Medicinal herbs offer valuable and efficient resources for addressing diverse diseases [42]. Topical application of herbal extracts, such as chamomile, Ocimum (basil), and Echinacea, has been found to offer therapeutic advantages within the oral cavity. These natural extracts, when applied directly to oral tissues, have demonstrated notable beneficial effects [43, 44].

This systematic review assessed the efficiency of the most widely used herbal plant, Salvadora persica (commonly known as miswak), in terms of inhibiting biofilm formation by cariogenic bacteria. Salvadora persica, commonly referred to as miswak, belongs to the Salvadoraceae plant family [13]. It predominantly thrives in subtropical and arid regions spanning the Middle East, Africa, and the Indian subcontinent [13, 45]. This plant’s fresh leaves, twigs, and roots have found applications both in daily dietary practices and traditional herbal therapy [13, 46].

Phytotherapeutic antimicrobial agents offer a potential alternative to synthetic compounds, considering the potential negative effects associated with the latter [47]. Several studies have underscored the variable antimicrobial activity of herbal-based toothpaste [12, 27, 48–51]. The investigations conducted by Mohammed [52] and Adwan et al. [53] yielded consistent findings, indicating the antimicrobial efficacy of toothpastes with miswak extract against various microorganisms. These outcomes are aligned with the findings synthesized in this comprehensive review [34, 35].

Standard oral hygiene practices, encompassing toothbrushing, flossing, and mouth rinses, primarily rely on mechanical actions to remove dental plaque and debris. The favorable attributes of miswak concerning dental and oral well-being arise from a dual mechanism. Firstly, its mechanical utility in brushing augments its beneficial effects. Secondly, its pharmacologically active components, including tannins that hinder glucosyltransferase enzyme activity, thereby reducing plaque and periodontal concerns, and resins that act as a defense against dental caries, contribute to its oral health merits [54]. Two randomized trials conducted in Iraq and Egypt, that compared the effects of miswak with regular toothbrushing, demonstrated miswak’s potential for plaque reduction and its noninferiority compared to conventional methods. The studies suggested that miswak-based products exhibit antimicrobial properties, offering benefits beyond mechanical cleaning. These findings align with miswak’s bioactive components, potentially enhancing its appeal as a holistic dental care tool [34, 37].

Scientific investigation is drawn to the concept of fluoridating miswak chewing sticks to combine the mechanical cleaning with the anticariogenic impact brought about by fluoride release into the oral cavity. According to Raina et al., plain miswak sticks and those impregnated with sodium fluoride were equally effective at lowering the levels of Streptococcus mutans in saliva. These findings are consistent with a RCT carried out in 2014 by Yavagal et al., which found that fluoridated miswak sticks could lower salivary S. mutans counts but not Lactobacillus counts [35].

Assays such as crystal violet staining and CLSM were utilized to assess the antibiofilm activity of miswak. These techniques provide valuable insights into the structural and microbial composition of biofilms. However, the number of studies utilizing these assays was limited, warranting further investigation to explore the impacts of miswak on biofilm formation as well as organization.

Regarding the anticaries activity, the studies primarily utilized clinical parameters such as the DMFS index, DMFT index, or ICDAS. However, the valuation of caries activity varied across the studies, making it challenging to draw definitive conclusions. The study by Taha et al. found that both miswak and standard preventive measures had a significant impact on reducing caries in young Egyptian adults, with no major variation between the 2 groups, indicating a potential reduction in caries activity with the use of miswak that could be comparable to conventional oral health measures [37]. The majority of the available literature supports the use of miswak in reducing caries incidence in the young population as well as adults [12, 27, 49]. However, further research with standardized and consistent caries assessment methods that could determine the caries activity in terms of indices and microbiological assay is necessary.

The long-term efficacy of miswak in maintaining oral health remains an area requiring further investigation. While several short-term studies have demonstrated its antibacterial effects, limited data exist on its sustained impact over extended periods. Factors such as frequency and technique of use, individual oral hygiene habits, and variations in miswak preparation may influence its long-term effectiveness. Evaluating miswak’s durability in maintaining plaque control, its ability to prevent biofilm maturation, and its long-term impact on overall oral microbiota composition would provide deeper insights into its effectiveness as a sustainable oral hygiene tool. Although our systematic review offers insightful comparisons between miswak and conventional oral hygiene practices, it is vital to recognize some limitations that might have affected how our results should be interpreted and extrapolated. The evaluated studies are subject to several potential limitations. A subset of these studies featured relatively small sample sizes that could impede the generalizability of their results. Additionally, certain investigations employed interventions of short duration, ranging from days to weeks, limiting insights into the potential long-term effects. Another noteworthy limitation was the absence of participant blinding in certain cases, which could introduce bias into the results. The heterogeneity of interventions across studies poses challenges in drawing cohesive conclusions. Moreover, the lack of follow-up in certain studies restricts the understanding of sustained intervention impacts. Miswak’s cultural importance may alter depending on the population, and cultural practices may have an impact on how it is used. The differences in oral habits, diet, oral microbiome, and compliance to the herbal treatment play a major role. The frequency and greater adherence to the use of miswak by traditional users may not be replicated by the nontraditional population, which highly impacts generalizability and study outcome. The applicability of our findings to other geographical areas may be impacted by this issue. These limitations collectively underscore the need for cautious interpretation of results and emphasize the importance of addressing these issues in future research endeavors.

5. Conclusion

Miswak (Salvadora persica) has demonstrated potential antibiofilm, antiplaque, and anticaries properties compared to conventional oral health measures. When Salvadora persica was used to maintain dental hygiene, there was a noteworthy decrease in the number of cariogenic bacteria and plaque. However, further research would establish its safety and efficacy, especially about long-term use and potential side effects. Additionally, the studies varied in methodology, sample size, and outcome measures, which limits the ability to draw definitive conclusions. The findings suggest that miswak could be a promising natural adjunct to conventional oral health measures in reducing dental biofilms and maintaining oral health.

Ethics Statement

The authors have nothing to report.

Consent

The authors have nothing to report.

Conflicts of Interest

The authors declare no conflicts of interest.

Author Contributions

Conceptualization, Ipsitha Vejendla; Jogikalmat Krithikadatta; Thilla Sekar Vinothkumar; Kumar Chandan Srivastava; and Deepti Shrivastava; methodology, Ipsitha Vejendla; Jogikalmat Krithikadatta; Thilla Sekar Vinothkumar; Kumar Chandan Srivastava; and Deepti Shrivastava; software, Jogikalmat Krithikadatta; Kumar Chandan Srivastava; Balqees Mohammad Dhuwayhi Alruwaili; and Manal Yahya Saleh Aljarid; validation, Balqees Mohammad Dhuwayhi Alruwaili; Manal Yahya Saleh Aljarid; and Deepti Shrivastava; visualization, Balqees Mohammad Dhuwayhi Alruwaili; Manal Yahya Saleh Aljarid; and Deepti Shrivastava; formal analysis, Thilla Sekar Vinothkumar; Deepti Shrivastava; and Kumar Chandan Srivastava; writing – original draft preparation, Ipsitha Vejendla; Jogikalmat Krithikadatta; and Kumar Chandan Srivastava; writing – review and editing, Ipsitha Vejendla; Jogikalmat Krithikadatta; Thilla Sekar Vinothkumar; Kumar Chandan Srivastava; Balqees Mohammad Dhuwayhi Alruwaili; Manal Yahya Saleh Aljarid; and Deepti Shrivastava; supervision, Jogikalmat Krithikadatta; project administration, Jogikalmat Krithikadatta and Kumar Chandan Srivastava; and funding acquisition, Deepti Shrivastava and Kumar Chandan Srivastava. All authors have read and agreed to the published version of the manuscript.

Funding

This study was not supported by any funding.