Antibacterial Efficacy of Conventional Versus Herbal Products on Streptococcus mutans in Adult Population- a Systematic Review & Meta-analysis

Background: Dental caries is challenging infectious disease, which is wide spread and difficult to control. Although it’s multifactorial, microorganisms especially cariogenic Streptococcus mutans plays a wide role in initiation and progression of dental caries. Objective: The present review mainly aimed to evaluate and assess the antibacterial efficacy of herbal versus conventional products on Streptococcus mutans. Data Sources: A search was execute in electronic database (i.e., PUBMEDCENTRAL, COCHRANE, LILAC, SCIENCEDIRECT, GOOGLE SEARCH) using following search terms alone and in combination by means of PUBMED search builder from January 1990 up to July 2019. Study Eligibility Criteria: Studies were stipulate if they met the following criteria: In vivo studies comparing herbal and conventional products on anticariogenic or antibacterial activity on Streptococcus mutans were selected. Participants and Intervention: Adult patients aged from 18-65 years with dental caries undergoing intervention of herbal products. Study Appraisal and Synthesis Material and Methods: Out of 225 studies collected from databases, only 6 studies were included and other 6 were collected by hand search. Finally 12 included studies were analyzed out of which 5 studies were considered for meta-analysis. Results: The results unveil that natural RESUMO


S Y S T E M AT I C R E V I E W
Antibacterial Efficacy of Conventional Versus Herbal Products on Streptococcus mutans in Adult Population-a Systematic Review & Meta-analysis INTRODUCTION D ental caries is a dynamic phenomenon, resulting in the localized dissolution and destruction of dental hard tissues, by acidic byproducts, resulted from bacterial fermentation of carbohydrates [1]. Ecological plaque hypothesis states the important role of microbes as a key factor for dental caries causation [2]. Although caries is multifactorial, the main causative etiological factors include bacteria such as Streptococcus mutans and Lactobacillus [3].
Dental caries is ubiquitous in nature. It results from the interaction of the dietary constituents with the specific causative microbe [1]. Ideally, Plaque serves as a reservoir providing the homeostatic environment suitable for the destructive consequence [2]. Dental plaque transforms to a cariogenic plaque biofilm, once the bacteria tends to colonize on the surfaces of the substrate [2].
Streptococcus mutans are highly acidogenic and acid tolerant [4,5,6]. They serve as a key contributor for the caries progression [4]. These bacteria utilize the dietary sucrose, to synthesize products exerted virtually homogeneous antibacterial effect against Streptococcus mutans when compared with the counterpart. Limitations: Review was assessing on patients with dental caries and studies previously assessed did not mention about the caries risk. Prevalence varies based on caries risk assessments. Study was concentrating only on single species Streptococcus mutans. But ideally caries is multifactorial. Conclusion: Although natural products were effective, the present systematic review does not furnish concrete evidence to a show increased antibacterial efficacy of natural products as compared to conventional products.
the larger amounts of extracellular polysaccharides, followed by initial substrate adherence using glucan [4]. It is believed that, reducing the mass of Streptococcus mutans in the dental biofilm could lower the incidence of dental caries [7]. So, disengagement of Streptococcus mutans bacteria by usage of anti-adhesion agents without affecting their viability might serve as a valuable aid in clinically reducing the causative organisms at the root level [7].
Current caries combating strategies concentrate on usage of broad-spectrum antimicrobials for therapeutic advantage [8]. Although, they have a beneficial effect in short span, they impose bad impact on long run. Resistance of the microorganisms to antibiotics is the current issue that has to be addressed [9]. There is a growing evidence suggesting that the frequent usage of antibiotics induces resistance and threatens the effectiveness of the treatment [9,10].
towards exploring the natural plant extracts [11]. Especially in dentistry, interest towards the usage of herbal products has increased.
Streptococcus mutans and Lactobacillus are the major microbes involved in the decalcification and tooth decay [13]. Ideally the caries combating strategies includes both mechanical and chemical plaque controlling methods, to prevent the disease progression [14]. So, basic mechanical plaque controlling methods alone may not be sufficient or effective to remove the cariogenic plaque. Adjunctive aids including chemical plaque controlling methods aid in better plaque removal [14].
So, considering all these facts, the present review was done to exploit and compare the benefits of various herbal formulations in reducing Streptococcus mutans levels in adult population.

Rationale of the Systematic review
The aim of this systematic review was to assess the anti-bacterial effects of herbal products with the compared conventional product against Streptococcus mutans in adult population.

OBJECTIVES
The present systematic review included the articles published on both conventional versus herbal products used for management of caries associated bacteria. Search was carried out using multiple terms including various tooth-pastes and mouth washes from January 1990 to July 2019. This is a first ever study which concentrated on the clinical trials evaluated mainly the herbal and conventional tooth-pastes and mouthwashes on reducing the Streptococcus mutans levels in patients with dental caries.

PICO Question
Do herbal products bring about noteworthy antibacterial activity and reduction of Streptococcus mutans from saliva juxtapose to conventional products?

PICO Analysis
• Population -Adult patients with dental caries • Intervention -Herbal products • Comparison -conventional products • Outcome -Reduction in Streptococcus mutans

Protocol for Registration:
The present study was registered and reviewed by the ethical committee of institutional Ethical Committee prior to the start of the research.

Types of Studies
Randomized clinical trials, comparative clinical trials, prospective clinical trials in which natural and conventional tooth-pastes and mouthwashes have been compared.

Types of Participants
Patients between 18-70 years of age with dental caries.

Types of Interventions
Herbal products and conventional products.

Types of Outcome Measures
Antibacterial efficacy against Streptococcus mutans.

Exclusion Criteria
The following studies were excluded,

Information Sources
For identification of studies included or considered for this review, detailed search strategies were developed for the database searched. The search was carried out from January 1990 to July 2019. All possible databases were searched and for precise selection of studies hand search were also carried out by the assessors involved in the search.

Searched Databases
• PubMed

Language
Full text articles in English were only selected.

Hand Search
The following journals was hand searched • Journal of Conservative dentistry • Journal of dental research • World Journal of Dentistry • Journal of international society of preventive and community dentistry.
• Journal of operative dentistry and endodontics.
• Journal of Islamic dental association of IRAN.
• Journal of oral and maxillofacial pathology.
• Journal of Ayurveda and holistic medicine.

SEARCH
Search was carried out in electronic database (i.e., PUBMEDCENTRAL, COCHRANE, LILAC, SCIENCEDIRECT, and GOOGLE SEARCH) using following search terms alone and in combination by means of PUBMED search builder from January 1990 up to July 2019.
Variables of interest (Table I) of the present systematic review were to assess the antimicrobial efficacy and anticariogenic activity of herbal agents against conventional agents on Streptococcus mutans in adult population.

S.No
Variables of Interest 1 Antibacterial efficacy and anticariogenic activity

Study Selection
The search identified 258 publications out of which 32 duplicates were removed and 200 were excluded after title search. 26 Full text articles were obtained for studies and evaluated. After evaluation, 13 were excluded (Table II) based on inclusion and exclusion criteria. Finally, 6 were included based on the aforesaid criteria. Following hand search, 6 articles were included as it satisfied the inclusion and exclusion criteria. Therefore, a total of 12 publications fulfilled all criteria for inclusion (Chart 1). The above analysis was done by two independent reviewers and incase of disagreement, consensus was reached after discussion with a third reviewer.

Data Collection Process and Data Items
The quality assessment of included trails was undertaken independently as a part of data extraction process, where assessment was based on four main quality criteria, which included: method of randomization, allocation concealment, outcome assessor blinding and completeness of follow up. Other methodological criteria included presence or absence of sample size calculation, comparability of groups at the start, clear inclusion and exclusion criteria.

Risk of Bias of Individual Studies
Risks of bias of included studies were assessed using Cochrane Risk of Bias assessment tool based on major and minor assessment criteria's. No risk of bias across the studies included in the present systematic review.

Risk of Bias in Included Studies
The assessments for the four main methodological quality items are shown in table.
The study was assessed to have a "High risk" of bias if it did not record a "Yes" in three or more of the four main categories, "Moderate" if two out of four categories did not record a "Yes", and "Low" if randomization assessor blinding and completeness of follow -up were considered adequate.

Study Selection
The purpose of this review is to evaluate the antibacterial efficacy of natural products versus conventional products against Streptococcus mutans (Table I).
The search identified 258 publications out of which 32 duplicates were removed and 200 were excluded after title search. 26 Full text articles were obtained for studies and evaluated. After evaluation, 13 were excluded (Table II) based on inclusion and exclusion criteria. Finally, 6 were included based on the aforesaid criteria. Following hand search, 6 articles were included as it satisfied the inclusion and exclusion criteria. Therefore, a total of 12 publications fulfilled all criteria for inclusion (Chart 1).
In the present systematic review, all 12 articles included were randomized controlled trials which compared the antibacterial efficacy of natural and conventional products by quantitative analysis using microbial culture method (Colony forming units) (Table III), (Table IV), (Table V).  There was a reduction in colony forming units from baseline to day 7 which was not statistically significant in both the groups and at 14 day there was a significant reduction in CFU counts, which was higher in herbal group.

Study Characteristics & Results of Individual Studies
Botelho MA et al. [28] evaluated and compared the antibacterial efficacy of an essential oil mouthwash comprising of L.sidoides with that of chlorhexidine. It was clearly shown that both the groups exerted a 58% reduction in Streptococcus mutans count at the end of 7 days.
Two studies established the effect of Triphala on Streptococcus mutans by comparing its antibacterial efficacy with chlorhexidine. In a study conducted by Srinagesh J et al. (2011) [29], there was a significant reduction in the colony forming units of Streptococcus mutans in both Triphala (83% and 67%) and chlorhexidine (80% and 65%) at 15 and 45 days respectively in a sample of 57 people. In another study done by Srinagesh J et al. (2012) [30], a CFU reduction of 17% and 44% was found at 48 hours and 7 days respectively in Triphala group while a reduction of 16% and 45% was seen in chlorhexidine group in a total sample size of 60 subjects.
Velmurugan A et al. [31] have compared the antibacterial efficacy of Emblica officinalis, Terminalia chebula with chlorhexidine. The results projected a marked decrease in Streptococcus mutans in all the three groups i.e; 78.1% in E.officinalis group followed by 67.8% in T.Chebula group, and 65.0% in chlorhexidine group post 90 minutes of usage in a total sample size of 45 subjects.
Usha C et al. [34], compared the anticariogenicity of Stevia rebaudiana with chlorhexidine and found 100% Streptococcus mutans reduction in both the groups post 8 days of administration in a total sample of 46.
In a clinical trial by Khairnar MA et al. [7], chlorhexidine was compared with cranberry and it was found that there were a 69% CFU reduction in chlorhexidine group and 68% CFU reduction in cranberry group after 2 weeks in sample of 50 patients.
Yadav M et al. [33], compared green coffee bean extract with chlorhexidine and found 51.5 % Streptococcus mutans reduction in coffee group and 55.60% reduction in chlorhexidine group after 2 weeks in a sample of 45 subjects.
Biria M et al. [35], study compared pistacia lentiscus extract tooth paste with fluoride tooth paste. Fluoride group showed 80.415% reduction in streptococcus mutans levels at1month interval and pistacia group showed only 61.7% reduction at 1 month interval, in a sample of 60.
When all the included studies were evaluated only two studies compared the effectiveness of herbal tooth pastes on Streptococcus mutans reduction [32,35]. Study by Biria M et al. [35], is the only study in literature search, which has evaluated the effectives of tooth paste alone without any adjunctive aid.
In all the studies compared, the reduction of Streptococcus mutans was almost insignificant or nearly approachable to conventional products (Table V, Table VI).

Risk of Bias Within and Across the Studies
The risk of bias for all the studies included in the present systematic review was assessed using Cochrane criteria (Table VIII), (Table IX). Four parameters were evaluated to assess the risk of bias on individual studies. Five out of twelve studies showed low risk of bias [7,28,29,30,31] and the remaining four showed moderate risk of bias [33,34,35,36]. Finally three included studies, showed high risk of bias [32,37,38].
Low risk of bias was shown in the study conducted by Srinagesh J et al. 2011 [32] as randomization, assessor blinding and dropouts or withdrawals if any, were well explained. Randomization and assessor blinding were done and well described in the trials reported by Khairnar [31] also, there were no incidence of dropouts or withdrawals in the aforesaid clinical trials as well. Therefore, the five studies discussed above have low risk of bias.
Srinagesh J et al. 2011 [29] described the limitations of their study emphasizing that only short-term effect of triphala was assessed against oral streptococci. Therefore more trials are required to explore long term antibacterial efficacy of triphala against various oral microorganisms. Yadav M et al. 2016[34]

Synthesis of Results & Additional Analysis
Meta-analysis was done for only five included studies [7,30,32,36,37]. Studies which provided the baseline & post-analysis data (Mean & S.D) were considered for Meta-analysis. Other seven studies [28,29,31,33,34,35,38] which analyzed the Streptococcus mutans count in terms of percentage reduction were considered for qualitative assessment.

Summary of evidence
The purpose of this review is to evaluate the antibacterial efficacy of natural products versus conventional products against Streptococcus mutans (Table I).
Literature has shown substantial evidence that; higher dental caries incidence was associated with infrequent tooth brushing than the counterpart [39]. Although brushing seems to be beneficial, it has no additional role in antibacterial activity or added beneficial anticariogenic activity, except for transient localized delivery of fluoride ions [40].
Hence, mouthwashes seemed to have an additional benefit in reducing the cariogenic plaque load, thereby enhancing the anticariogenic activity. Although, when mouthwashes are compared, most of the studies in the literature were concentrated on usage of chlorhexidine at different concentrations and it's considered to be a gold standard [41].
In the present systematic review too, most of the studies compared only the chlorhexidine at different concentrations ranging from 0.2 to 0.12 as a conventional product (Table IV, Table V).
As mentioned earlier, due to increasing threat of using antimicrobial agents leading to development of resistant microorganisms. The herbal trend is increased and various studies using animal and human tests, evaluated, these herbal compounds exhibiting antibacterial activity against various pathogens, anti-adhesive and inhibitory activity against the extracellular polysaccharide [42].
Among the various compounds evaluated, the polyphenolic compounds claimed to have maximal beneficial effect.

Report on Quality of Evidence Looked Upon
Twelve trials were included in this review. All 12 studies included in this review have a level of evidence 2 (Table VII). Thus the level of evidence is high.

Inference
From this systematic review it can be concluded that natural products can be used as an alternative to conventional products and proved to have a beneficial activity against Streptococcus mutans.

Limitations
Although, meta-analysis showed no significant difference between the conventional and herbal products on Streptococcus mutans reduction, the included studies were very less and most of them were of high risk. Most of the studies with high quality were not included for meta-analysis, as the data was provided in terms of percentage reduction. Studies included assessed only one pathogen and concentration was on antimicrobial reduction. But when dental caries is considered, it's multifactorial and various factors come into play to create a caries susceptible environment. None of the studies included concentrated on the caries index and susceptibility. The assessment was only based on the baseline microbial count. When critically appraised, studies concentrated mostly on different chlorhexidine for mutations and to a little extent of flouride combinations. Although, many other conventional agents proved to have a beneficial role, the dearth of studies concentrating on this aspect is low or almost nil. The assessments periods and follow up periods were also less to come to a specific conclusive remark.

Future implications
When the present review was considered, most of the research was concentrated on usage of mouth washes and the literature was scarce on comparing herbal versus conventional tooth pastes. When mouthwashes alone are considered, most of the studies compared and evaluated to chlorhexidine as a conventional product. None of the studies included a comparison on fluoride mouthwashes with the herbal products on re-mineralizing effect. It is a known fact that several herbal plant extracts have an additional re-mineralizing effect. So, it would be beneficial if future studies concentrate more on remineralizing mouthwashes. As a known fact, it (I² (%) = 94.315, p=0.043) is not always possible to achieve beneficial effect, with a single constituent. To combat the future antimicrobial agents, its better if future studies concentrate on the combination of plant extracts in obtaining the beneficial effect.

CONCLUSION
Herbal products were equally effective as conventional products in reducing Streptococcus mutans levels in adult population.

FUNDING
The present study was funded by Dr. Duddukuru Balaji, " Royal Pharmacy", 2244, Church Avenue, Brooklyn, NY, 11226, USA. We acknowledge them for the financial support.

Implications of Key Findings:
The review revealed a unique perspective about the herbal agents which proved to be equally efficacious against Streptococcus mutans as conventional agents. This review highlighted the importance of herbal agents to combat the present antimicrobial resistance especially in relevance to oral pathogens.