‌ In recent years, herb products are well-known in the medical industry as they possess various benefits such as combating diseases and nurturing health. Some benefits of herbs in treatments is that it has anti-inflammatory, antibacterial properties, without leaving any residues or toxins in the body. Thailand has recently been supportive of the research of Thai medicinal plants to be used in medical treatments as they aim to decrease the chemical imports from foreign countries. Thai Medicinal plants are used in dentistry, studies on treatment of periodontitis and antimicrobial activities against caries have been conducted. Root Canal Bacterias: Peptostreptococcus,Prevotella,Porphyromonas,Fusobacterium  Actinomyces Obligate anaerobe, which causes inflammation. In this research conducted by dentists from Faculty of Dentistry, Thammasat University, they have concluded that 7 types of Thai medicinal plants have shown positive results on the antimicrobial efficiency of root canal bacteria either in the form of single or mixed cultures of microorganisms. In this experiment, they used the agar diffusion method to test the efficiency of sensitivity, resistance, and zone of inhibition. Another method that they used is called the broth dilution, to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Lastly, they measured the ability of Thai Microbiological treatment of herbal extracts in the form of biofilm in the real root canal (ex vivo tooth model). 

This source is relevant for my EE as it can extend my toothpaste formula, such as another toothpaste designed for adults especially for the purpose of root canal treatment as they are more prevalent in adults after their thirties.

The author argues that although these 7 herbs possess antimicrobial activity against microorganisms. However, the efficiency is not as high as the existent antimicrobial agents (Mouth wash) in the market. 

The methodology of this investigation: Aliquots of suspension of each bacterial species were inoculated onto a horse blood agar plate with TCMs soaked separately on 6 mm paper disks. The plates were incubated for 48 h anaerobically and the mean diameters of growth inhibition of three different areas obtained. 0.2% (w/v) chlorhexidine was used as a positive control. Broth microdilution assay was used to determine minimum inhibitory concentration and minimum bactericidal concentration. 

The author proposed that there is a need to search for alternatives from Existing antimicrobial mouth rinses, such as chlorhexidine and Listerine. Since they are inedible and may be harmful if ingested, therefore there must be an alternative for less harmful agents that also has similar antimicrobial properties.  

In this investigation, Chlorhexidine gluconate, a common oral antiseptic, at a concentration of 0.2% (w/v) was used as a positive control. One advantage of this study is that it has a positive control, which serves as an indicator of acceptability of the assay, and ensures that the assay is working as intended. The researchers have found out that 2 of 20 Traditional Chinese medicine extracts tested demonstrated consistent antimicrobial activity with zones of growth against Streptococcus mutans. The average inhibition zone diameter for Cortex phellodendri (huang bai) and Fructus armeniaca mume (wu mei) to S. mutans, was 8 mm and 9 mm. The author concluded that Fructus armeniaca mume had antimicrobial resistant against S. mitis, S. sanguis, S. mutans and P. gingivalis in vitro because there might be a possibility that its acidic content (citric acid, malic acid, oxalic acid, succinic acid, fumaric acid, tartaric acid, picric acid) accounts for its wide antibacterial spectrum.

There are limitations to this study which is how it is a pilot study. A pilot study is a small-scale study conducted in preparation for larger investigation studies, therefore there are possibilities of inaccurate prediction and results, and problems with funding. This research study provides a range of oral bacterias to be tested, however this study lacks a detailed comparison between these 4 oral bacterias.       

This is relevant to my extended essay as I can select Cortex phellodendri (huang bai) and Fructus armeniaca mume (wu mei) as the Chinese herbs which will be tested. 

In this investigation, 120 patients with chronic gingivitis were separated into two groups: Experiment and control. Patients in the experiment group used a Pudilan extract - containing toothpaste， while the patients in the control group used a toothpaste without the Pudilan extract. The author measured the que Index (PI), Gingival Index (GI), Bleeding Index (BI), and Bleeding On Probing proportion (BOP%) at baseline, 4 weeks, 8 weeks and 12 weeks after using the toothpaste.  

The author of this source also dedicated a section of this article to writing about ethical considerations, since it deals with human subjects. The results that the author has obtained from this investigation is that in the experimental group, the Blood on Probing proportion (%) was significantly lower in comparison to the control group. In addition, the decline of the Plaque Index (PI), Gingival Index (GI) for the experiment group after 4,8, and 12 weeks was significantly higher than the control group, indicating that there was less dental plaque accumulation. The author has concluded that the pudilan-extract toothpaste demonstrated good effect on relieving symptoms of chronic gingivitis, inhibition of plaque formation, reduction in gingival inflammation and the degree of bleeding. From the results obtained, the author believes that Pudilan extract toothpaste has prospective application potential in the prevention and treatment of chronic gingivitis. 

This source is relevant for my herb choice selection, as I can test pudilan-extract as one of my variables as it’s classified as a chinese herb. I can test its antimicrobial properties against the oral bacteria by measuring the zone of inhibition, and compare it to the results made from this investigation. Although in my extended essay, it is the zone of inhibition, it can be compared to the indexes, since in the end, both are parameters which can measure the effectiveness.  

This article also provides multiple diagrams such as how to measure the zone of inhibition, the pattern the swab should follow, for a clearer understanding of the procedure. 

Moreover, some aspects of this article is useful for my extended essay because it provides a step by step method for the Preparation of Bacterial Suspension, Inoculation of the MH plate, and Inoculum preparation. This can be useful when writing the methodology section.  

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A brief paragraph summarizing the source, explaining its credibility and relevance to the topic

A. Thailand Local Context of Dental Caries 

B. Streptococcus lactis TISTR 457  

C. Mechanism of Streptococcus mutans causing Dental Caries

Agree:
Source A
Source C
Source D
Source E

Disagree:  
Source B

B: Preparation of De Man Rogosa Sharpe Agar Plate

C: Agar Well Diffusion (measuring the Zone of inhibition) 

D: Safety & Environmental Concerns
E: Aseptic Technique