Year : 2007 | Volume
: 18 | Issue : 4 | Page : 148--151
The effect of mango and neem extract on four organisms causing dental caries: Streptococcus mutans, Streptococcus salivavius, Streptococcus mitis, and Streptococcus sanguis: An in vitro study
GM Prashant1, GN Chandu1, KS Murulikrishna2, MD Shafiulla3,
1 Department of Preventive and Community Dentistry, College of Dental Sciences, Davangere - 577 004, Karnataka, India
2 Department of Pharmacognosy, Bapuji College of Pharmacy, Davangere - 577 004, Karnataka, India
3 Department of Community Dentistry, Vishnu Dental College and Hospital, Bhimavaram - 534 202, Andhra Pradesh, India
G N Chandu
Department of Preventive and Community Dentistry, College of Dental Sciences, Davangere - 577 004, Karnataka
Background and Objectives: Chewing twigs of the mango or neem tree is a common way of cleaning the teeth in the rural and semi-urban population. These twigs are also believed to possess medicinal properties. The present study was conducted to evaluate the antimicrobial effects of these chewing sticks on the microorganisms Streptococcus mutans , Streptococcus salivarius , Streptococcus mitis , and Streptococcus sanguis which are involved in the development of dental caries. An additional objective was to identify an inexpensive, simple, and effective method of preventing and controlling dental caries.
Materials and Methods: The sticks were sun dried, ground into a coarse powder, and weighed into 5 gm, 10 gm, and 50 gm amounts. These were added to 100 ml of deionized distilled water. After soaking for 48 h at 4°C, the water was filtered. The filtrate was inoculated onto blood agar plates containing individual species of microorganisms and incubated at 37°C for 48 h.
Results: Mango extract, at 50% concentration, showed maximum zone of inhibition on Streptococcus mitis . Neem extract produced the maximum zone of inhibition on Streptococcus mutans at 50% concentration. Even at 5% concentration neem extract showed some inhibition of growth for all the four species of organisms.
Interpretation and Conclusion: A combination of neem and mango chewing sticks may provide the maximum benefit. We recommend the use of both the chewing sticks.
|How to cite this article:|
Prashant G M, Chandu G N, Murulikrishna K S, Shafiulla M D. The effect of mango and neem extract on four organisms causing dental caries: Streptococcus mutans, Streptococcus salivavius, Streptococcus mitis, and Streptococcus sanguis: An in vitro study.Indian J Dent Res 2007;18:148-151
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Prashant G M, Chandu G N, Murulikrishna K S, Shafiulla M D. The effect of mango and neem extract on four organisms causing dental caries: Streptococcus mutans, Streptococcus salivavius, Streptococcus mitis, and Streptococcus sanguis: An in vitro study. Indian J Dent Res [serial online] 2007 [cited 2019 Nov 19 ];18:148-151
Available from: http://www.ijdr.in/text.asp?2007/18/4/148/35822
Dental caries is steadily increasing in the underdeveloped and developing countries. Treatment is expensive and not a realistic option for the poor. Hence, there is an urgent need to promote traditional preventive measures that are acceptable, easily available, and cost effective.
Chewing sticks have been widely used in the Indian subcontinent, the Middle East, and Africa since ancient times. The chewing stick can be a good alternative to the toothbrush as a means of preventing oral and dental disease. It is suitable for cleaning the teeth, costs little, possesses various medicinal properties, and is easily available in the rural areas of the developing countries. It is also an oral hygiene tool that requires no expertise or special resources for its production. 
The present study aimed to identify and evaluate an inexpensive, simple, and effective method for preventing and controlling dental caries.
To evaluate the antimicrobial effects of herbal chewing sticks of mango and neem on microorganisms (Streptococcus mutans, Streptococcus salivarius, Streptococcus mitis, and Streptococcus sanguis) that are involved in the process of causing dental caries.
Materials and Methods
The following materials were used in this study:
Dried chewing sticks of:
i) Mango (Mangifera indica)
ii) Neem (Azadirachta indica)
Four species of microorganisms:
i) Streptococcus mutans (MTCC 890)
ii) Streptococcus salivarius (ATCC 9222)
iii) Streptococcus mitis (MTCC 2695)
iv) Streptococcus sanguis (ATCC 10556)
Blood agar platesVernier calipers
Procurement of the chewing sticks
Small branches of the locally available mango and neem trees were cut into pieces of approximately 15 cms. These were authenticated by the Department of Botany of Dharma Ratnakara Muddurayappa Science College, Davangere, India. The twigs of mango and neem were tagged for identification and sun dried for two days.
Preparation of the extract
The dried sticks of mango and neem were ground separately into a coarse powder. The power was weighed into 5 gm, 10 gm, and 50 gm amounts and transferred into labeled bottles, to each of which was added 10 ml of sterile, deionized distilled water. The mixture was then shaken well by hand and allowed to soak for 48 h at 4°C. It was then was filtered to get extracts of 5%, 10%, and 50% concentration of both mango and neem.
Procurement of the microorganisms
Freeze-dried forms of the microorganisms Streptococcus mutans and Streptococcus mitis were obtained from Microbial Type Culture Collection, Chandigarh, and Streptococcus salivarius and Streptococcus sanguis were obtained from American Type Culture Collection, USA.
Preparation of the culture media for the study
The ampoules containing freeze-dried forms of the microorganisms were opened and the contents were added to nutrient broth which was incubated at 37°C for 24 h. A sterile cotton swab was dipped into the nutrient broth and then inoculated on to the agar plate which was incubated at 37°C overnight. The growth obtained on the agar plate was transferred on to a blood agar plate to test the antimicrobial activity of the herbal extract. 
Ditch plate method
Ditches were prepared on the agar plates at 3 individual quadrants streaked . The ditches were filled with one drop of the extract, repeating the same procedure for the three different concentrations of both the mango and neem extracts. Sterile, deionized distilled water was taken as control. The plates were then incubated at 37°C for 48 h, after which they were examined for the size of the inhibition zones. The inhibition zones were measured on the underside of the plate, using Vernier calipers. ,
The collected data was analyzed using the following statistical tests: 
Mean value One way analysis of variance (ANOVA) Mann-Whitney U test
The effect of various concentrations of mango extract on Streptococcus mutans, Streptococcus salivarius, Streptococcus mitis, and Streptococcus sanguis is tabulated in [Table 1]A-D respectively. The effect of various concentrations of neem extract on Streptococcus mutans, Streptococcus salivarius, Streptococcus mitis, and Streptococcus sanguis is tabulated in [Table 2]A-D respectively
The extracts of mango and neem chewing sticks in the concentration of 5%, 10%, and 50% were tested for antimicrobial activity. The species of microorganisms used for the study were Streptococcus mutans, Streptococcus salivarius, Streptococcus mitis, and Streptococcus sanguis.
Mangifera indica contains tannins, bitter gum, and resins.  At 5% concentration, this herbal extract did not show any antimicrobial activity, but at higher concentrations antimicrobial activity was present. When compared to neem, extract of mango chewing stick showed more antimicrobial activity, i.e., at 50% concentration the maximum zone of inhibition for Streptococcus mitis was 5.0 mm. This could be due to the presence of a combination of the ingredients mentioned earlier.
Tannins and resins supposedly have an astringent effect on the mucous membrane, and they form a layer over enamel, thus providing protection against dental caries. In our review of the literature we could not find any other study that has examined the benefits of the extract of mango chewing sticks.
Neem contains the alkaloid margosine, resins, gum, chloride, fluoride, silica, sulfur, tannins, oils, saponins, flavenoids, sterols, and calcium.  Even at 5% concentration this extract showed some antimicrobial activity. Maximum anitimicrobial activity was observed on Streptococcus mutans at 50% concentration, with a zone of inhibition of 3.8 mm. This may be due to the presence of fluoride, which is known to exert an anticariogenic action, and silica acting as an abrasive and preventing accumulation of plaque; alkaloids, known to exert an analgesic action, also contribute towards dental well-being. The oils have carminative, antiseptic, and analgesic effects. Tannins exert an astringent effect and form a coat over the enamel, thus protecting against tooth decay. Wolinsky et al.  reported that the pretreatment of saliva-conditioned hydroxyapatite with neem-stick extract prior to exposure to bacteria, yielded significant reduction in bacterial adhesion. This result suggests that neem-stick extract can reduce the ability of some streptococci to colonize tooth surfaces. Another study conducted by Khalid in 1999  at Saudi Arabia examined the effectiveness of the antimicrobial activity of aqueous extracts of neem at various concentrations. He reported that neem was effective at 50% concentration on Streptococcus mutans.
From the findings of our study it appears that it may be possible to maximize the antimicrobial effect of the chewing stick extracts by using them in combination. Usually only one type of chewing stick is used by any one individual but, perhaps, people can be encouraged to use a combination of the chewing sticks for better oral cleanliness and protection against oral bacteria.
This study was conducted in vitro with the extracts of chewing sticks. The duration of the contact of the extract with the microorganisms in the oral cavity in vivo is not clear.
Further studies comparing the prevalence of dental caries among users and nonusers of chewing sticks should help elucidate the picture.
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