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ORIGINAL ARTICLE
Year : 2021  |  Volume : 12  |  Issue : 1  |  Page : 8-12

Assessment and comparison of toothpastes for pH and antibacterial effect against Streptococcus mutans: An in vitro study


1 Department of Public Health Dentistry, A J Institute of Dental Sciences, Mangalore, Karnataka, India
2 Department of Microbiology, A J Institute of Medical Sciences, Mangalore, Karnataka, India

Date of Submission21-Dec-2020
Date of Decision18-Feb-2021
Date of Acceptance19-Feb-2021
Date of Web Publication30-Mar-2021

Correspondence Address:
Dr. R S Roshni
Department of Public Health Dentistry, A J Institute of Dental Sciences, NH 66, Kuntikana, Mangalore - 575 004, Karnataka
India
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DOI: 10.4103/srmjrds.srmjrds_137_20

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  Abstract 

Introduction: One of the universally practiced oral hygiene measures is tooth brushing with toothpaste. Each toothpaste is composed of different ingredients. The extent of the antimicrobial activity of toothpastes against cariogenic bacteria is still unclear. Toothpaste with the correct pH will help to neutralize the acidic activity of the oral cavity. However, there are lack of studies to determine pH of different toothpastes. Aim: The aim is to assess and compare the commercially available toothpastes for pH and antibacterial activity against Streptococcus mutans. Materials and Methods: Commercially available toothpastes composed of varying ingredients available in the local market were included in the study. The pH of the toothpastes was assessed using pH meter. The antimicrobial activity was assessed by making serial dilutions for each selected toothpastes in 1:1, 1:2, 1:4, and 1:8 ratio using distilled water. At different concentrations, the antimicrobial activity of the toothpastes against S. mutans was determined by the agar well diffusion method. The diameter of zones of inhibition (mm) was measured for assessing the antimicrobial activity. Results: The mean pH of toothpastes ranged from 7.262 ± 0.414 to 7.729 ± 0.534. All toothpastes showed antimicrobial activity against S. mutans in all four dilutions 1:1, 1:2, 1:4, 1:8. Data were analyzed using the Statistical Package for the Social Sciences version 22 software (IBM Corporation). - Analysis of Variance was used to analyze data. Conclusion: The present study showed that the pH of all the toothpastes are above that of critical pH. All the toothpastes had shown antimicrobial activity against S. mutans at varying dilutions.

Keywords: pH, Steptococcus mutans, toothpastes


How to cite this article:
Shetty PJ, Roshni R S, Gomes L. Assessment and comparison of toothpastes for pH and antibacterial effect against Streptococcus mutans: An in vitro study. SRM J Res Dent Sci 2021;12:8-12

How to cite this URL:
Shetty PJ, Roshni R S, Gomes L. Assessment and comparison of toothpastes for pH and antibacterial effect against Streptococcus mutans: An in vitro study. SRM J Res Dent Sci [serial online] 2021 [cited 2021 Jun 15];12:8-12. Available from: https://www.srmjrds.in/text.asp?2021/12/1/8/312474


  Introduction Top


The oral cavity acts as a paradise for Gram-positive and Gram-negative microorganisms. The formation of biofilm is an innate process that provides a base for pathogenic bacteria, thereby promoting the development of dental caries and periodontal diseases. Streptococcus mutans is one of the principal opportunistic pathogenic microorganisms causing dental caries. The major cause for the accumulation of these pathogenic microbes is poor oral hygiene.[1]

One of the universally practiced oral hygiene practices is tooth brushing with toothpaste. Each toothpaste is composed of different ingredients. The most commonly found components in toothpaste are abrasive, surfactant, humectant, binding agents, flavoring agents, preservatives, sweeteners, fluorides, and others.[2] The ability to eliminate pathogenic oral microorganisms determines the success of any toothpaste.[3] To control dental plaque and prevent dental disease antimicrobial agents have been added to toothpastes.[4] The extent of antimicrobial activity of toothpastes against cariogenic bacteria is still unclear as each toothpaste has different ingredients.[5]

pH indicates the acidity or alkalinity. The scale of pH goes from 0 to 14, while pH of 7 is considered neutral. pH plays an important role in the remineralization and demineralization of enamel. It is essential to maintain a pH balance in the oral cavity as it plays a crucial role to help fight off dental caries. The oral cavity must maintain a pH of at least 5.5 known as critical pH below which demineralization occurs. Hence, it is necessary to use toothpaste with the correct pH that will help to neutralize the acidic activity of the oral cavity, thereby providing a healthy environment for teeth.[6] There are lack of studies to determine pH of different toothpastes.

Hence, the present study is aimed to assess and compare the commercially available toothpastes for pH and antibacterial activity against S. mutans.

Objectives of the study

  1. To assess and compare the pH of different commercially available toothpastes
  2. To assess and compare the antibacterial effect of different commercially available toothpastes against S. mutans.



  Materials and Methods Top


Study site

The study was conducted at the Department of Biochemistry for the determination of pH of toothpastes and Department of Microbiology, AJ Institute of Medical Sciences, Mangalore for determination of the antibacterial activity of toothpastes against S. mutans.

Selection of toothpastes

In advance of the commencement of the study, different brands of toothpastes that are commercially available were obtained. Twenty commercially available toothpastes which are commonly available with different ingredients were selected for the present study based on convenience and categorized as herbal, desensitizing, and regular toothpastes [Table 1]. To maintain standardization, the toothpastes selected for the present study had a date of manufacture within the past 6 months.
Table 1: Toothpastes and their contents

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pH determination

In a 50 ml beaker, 10 g of the toothpaste was dispensed and 10 ml of distilled water was added and stirred well to make a thorough aqueous suspension of about 50%. The pH of the suspension was determined within 5 min using pH meter.[7]

Test microorganisms

S. mutans was the bacterial strain used.

Dilution of toothpastes

Two grams of each selected toothpaste is mixed with 2 ml of sterile pyrogen-free distilled water to obtain 1:1 dilution. The serial dilutions were made by further diluting the toothpaste dilution in sterile distilled water and three different dilutions of 1:2, 1:4, 1:8 (toothpaste: Sterile distilled water) were obtained.[1]

Microbiological procedure

Modified agar well diffusion method was used to determine the antimicrobial activity of toothpastes at different concentrations. Blood agar plates were used and four well for each of the dilution was made using gel puncture creating wells of diameter 5 mm at equidistance and the dilution to be introduced in each well was marked. Lawn culture of the test organisms was made on the blood agar plates using a sterile cotton swab and the plates were allowed to dry for 15 min. Toothpaste dilutions at different concentrations were introduced into each of the wells as marked. The plates-containing different toothpaste dilutions were incubated at 37°C for 24 h. By measuring the diameter of zones of inhibition (in mm) the antimicrobial activity was assessed.[8] This was done in duplicates.

Statistical analysis

The collected data were entered into excel spreadsheet and statistical analysis was done using the IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp. Descriptive statistics such as mean and standard deviation were calculated for pH and antimicrobial activity against S. mutans. One-way Analysis of Variance was used to compare between groups for pH and antimicrobial activity against S. mutans. The level of significance was set at 0.05.


  Results Top


pH of toothpastes

pH of all toothpastes were above critical pH. Herbal toothpastes showed the highest pH with mean of 7.729 ± 0.534 followed by desensitizing toothpastes with mean pH of 7.420 ± 0.46 and regular toothpaste showed lowest pH with mean of 7.262 ± 0.414. There was no statistically significant difference in the pH between the three groups of toothpastes at different dilutions (P > 0.05) [Table 2].
Table 2: pH of toothpastes

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Antimicrobial activity of toothpastes against Streptococcus mutans

All toothpastes showed antimicrobial activity against S. mutans in all four dilutions 1:1, 1:2, 1:4, 1:8. At 1:1 dilution regular toothpastes showed a mean zone of inhibition of 23.12 ± 5.724 mm and desensitizing toothpastes showed a mean zone of inhibition of 23.10 ± 1.084 mm and the lowest mean zone of inhibition was shown by herbal toothpastes with 21.64 ± 2.135 mm. In 1:2 dilution desensitizing toothpastes showed the highest zone of inhibition with a mean of 22.90 ± 0.822 mm, followed by regular toothpastes with mean of 22.25 ± 3.694 mm and lowest by herbal toothpastes with a mean of 21.43 ± 2.225 mm. In 1:4 dilution, desensitizing toothpastes showed the highest zone of inhibition with mean of 22.70 ± 1.151 mm, followed by regular toothpastes with zone of inhibition of 21.81 ± 3.283 mm and lowest by herbal toothpastes with mean of 21.43 ± 2.878 mm. In 1:8 dilution desensitizing toothpastes showed highest zone of inhibition with mean of 22.90 ± 1.884 mm, followed by regular toothpaste with a mean of 21.75 ± 3.317 mm and lowest by herbal toothpastes with a mean of 21.29 ± 3.352 mm. There was no statistically significant difference in the antimicrobial activity against S. mutans between the three groups of toothpastes at different dilutions (P > 0.05) [Table 3].
Table 3: Antimicrobial activity of toothpastes against Streptococcus mutans

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  Discussion Top


People mainly use tooth brushing with toothpaste as the common oral hygiene practice to prevent oral diseases. Several commercially available toothpastes are marketed well highlighting their properties. Still, there is a dilemma because every toothpaste contains different active ingredients which may have varying effects when compared to others.[1]

Acidic pH encourages the growth of oral microorganisms that cause dental caries. Enamel demineralization and root resorption occur at pH lower than 5.2–5.8 which have been reported as critical pH.[9] The study by Oyewale AO showed that most of the toothpastes (60%) had neutral pH, 35% had acidic pH, and only those commercialized as herbal toothpaste had alkaline pH.[10] However, the present study showed that the mean pH of toothpastes ranged from 7.729 ± 0.534 to 7.262 ± 0.414.

In the present study, antimicrobial activity was shown by all toothpastes at 1:1, 1:2, 1:4, and 1:8 dilutions against S. mutans. The study by Roopavathi et al. showed that the antimicrobial activity against S. mutans decreased with increasing dilutions and few toothpastes did not show any antimicrobial activity against S. mutans even at 1:1 dilutions.[1] A study by Kurian M and Geetha RV showed that fluoride toothpaste-containing triclosan had high antimicrobial efficiency followed by herbal toothpaste which had constituents such as alkaloids, flavonoids, polyphenols, and lectins.[8] Several antimicrobial agents are added to the toothpastes to increase their effectiveness against microorganisms causing dental caries.

Triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether) has a broad spectrum of antibacterial, anti-inflammatory, antimicrobial activity which has been shown in numerous in vitro studies. Furthermore, it has significantly improved plaque control.[11] Fluorides have antimicrobial activity and have also been documented that will help to prevent, suppress, or alter the initiation and progression of dental caries more effectively.[12] Calcium and phosphate supplementation in toothpastes can elevate the concentration of these ions in the oral cavity, thereby increasing fluoride uptake and pave way for improving remineralizing potential. Sodium bicarbonate has shown promising effects on modifying dental caries formation. It creates an adverse environment for the growth of aciduric bacteria by increasing the pH in saliva. It can also modify the virulence characteristics of the bacteria that cause dental caries, and thereby prevent reduced enamel solubility and increase the remineralization ability of enamel.[13]

Assessing the antimicrobial activity of toothpaste is crucial because they contain a complex mixture of various active ingredients.[14] All toothpastes showed antimicrobial activity at varying dilutions which might be due to the various active chemical ingredients such as triclosan, fluorides, calcium, phosphate, or sodium bicarbonate.[15]

Herbal formulations are also equally efficient to chemical formulations. The usage of natural substances for the treatment of dental diseases has increased nowadays. The effective antimicrobial activity of herbal toothpastes might be because of the presence of secondary metabolites such as flavonoids, polyphenols, alkaloids, and lectins. Nowadays, fluorides are used along with herbal toothpastes in combinations to prevent dental caries.[16]

A balance usually exists in an individual's oral microflora. If the equilibrium is lost, the opportunistic microorganisms proliferate and it initiates the progression of dental diseases. So the formulations identified as having the largest zone of inhibition against S. mutans need not be necessarily superior to those with a smaller diameter zone of inhibition. The formulations used in-vivo is likely to be influenced by oral conditions. The level at which antimicrobial properties are buffered or lost in the oral cavity is unknown. The results cannot be generalized as the impact of oral environmental factors that might affect the pH and antimicrobial activity was not assessed in this study.


  Conclusion Top


The present study had shown that the pH of all toothpastes was above the critical pH. All toothpastes had shown antimicrobial activity against S. mutans at varying dilution. The results may vary when used in an oral environment. Several factors such as salivary composition, flow rate, normal oral flora, and other factors will influence its antimicrobial effects. The pH in individual's oral environment is dependent on the buffering capacity of their saliva and pH might vary when used in the oral cavity. Hence, in-vivo studies may also be required for further understanding. The clinical significance of the study is limited as the study was conducted in vitro. The results need not be translated into clinical effectiveness as there is an interplay of multiple factors causing oral disease. This in-vitro study aids us in the selection of the toothpaste with better antimicrobial activity and near-neutral pH which can have a better anti-plaque effect.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Roopavathi KM, Gopal SV, Pusphpalatha G, Bennadi D, Renushri BV, Madhura AS. Antimicrobial efficacy of commercially available toothpastes – An in vitro study. J Young Pharm 2015;7:187-93.  Back to cited text no. 1
    
2.
Souza Rodrigues RD, Ferreira SS, D'Almeida-Couto RS, Lachowski KM, Sobral MA, Marques MM. Choice of toothpaste for the elderly: An in vitro study. Braz Oral Res 2015;29:1-7.  Back to cited text no. 2
    
3.
George D, Bhat SS, Antony B. Comparative evaluation of the antimicrobial efficacy of aloe vera tooth gel and two popular commercial toothpastes: An in vitro study. Gen Dent 2009;57:238-41.  Back to cited text no. 3
    
4.
Sadeghi M, Assar S. An in vitro antimicrobial activity of ten Iranian-made toothpastes. Dent Res J (Isfahan) 2009;6:87-92.  Back to cited text no. 4
    
5.
Randall JP, Seow WK, Walsh LJ. Antibacterial activity of fluoride compounds and herbal toothpastes on Streptococcus mutans: An in vitro study. Aust Dent J 2015;60:368-74.  Back to cited text no. 5
    
6.
Bardal PA, Olympio KP, da Silva Cardoso VE, de Magalhães Bastos JR, Buzalaf MA. Evaluation of total pH and soluble and ionic fluoride concentrations in dentifrices commercially available in Brazil. Oral Health Prev Dent 2003;1:283-9.  Back to cited text no. 6
    
7.
Kisan M, Sangathan S, Nehru J, Pitroda SG. Indian Standard- Toothpaste Specifications. New Delhi: Bureau of Indian Standars; 2001.  Back to cited text no. 7
    
8.
Kurian M, Geetha RV. Effect of herbal and fluoride toothpaste on Streptococcus mutans – A comparative study. J Pharm Sci Res 2015;7:864-5.  Back to cited text no. 8
    
9.
Price RB, Sedarous M, Hiltz GS. The pH of tooth-whitening products. J Can Dent Assoc 2000;66:421-6.  Back to cited text no. 9
    
10.
Oyewale AO. Estimation of the essential inorganic constituents of commercial toothpastes. J Sci Ind Res 2005;64:101-7.  Back to cited text no. 10
    
11.
Gautam B, Dongol E, Shrestha A. In-vitro antimicrobial activity of different toothpastes. J Kathmandu Med Coll 2017;6:52-8.  Back to cited text no. 11
    
12.
Kanchanakamol U, Umpriwan R, Jotikasthira N, Srisilapanan P, Tuongratanaphan S, Sholitkul W, et al. Reduction of plaque formation and gingivitis by a dentifrice containing triclosan and copolymer. J Periodontol 1995;66:109-12.  Back to cited text no. 12
    
13.
Prasanth M. Antimicrobial efficacy of different toothpastes and mouthrinses: An in vitro study. Dent Res J (Isfahan) 2011;8:85-94.  Back to cited text no. 13
    
14.
Vranić E, Lacević A, Mehmedagić A, Uzunović A. Formulation ingredients for toothpastes and mouthwashes. Bosn J Basic Med Sci 2004;4:51-8.  Back to cited text no. 14
    
15.
De Rossi A, Ferreira DC, da Silva RA, de Queiroz AM, da Silva LA, Nelson-Filho P. Antimicrobial activity of toothpastes containing natural extracts, chlorhexidine or triclosan. Braz Dent J 2014;25:186-90.  Back to cited text no. 15
    
16.
Prasanna SG, Abilasha R, Gopinath. In vitro comparison of antimicrobial efficacy of different toothpastes. J Pharm Sci Res 2016;8:1195-8.  Back to cited text no. 16
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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