Comparative evaluation of antimicrobial efficacy of three remineralizing tooth pastes – An in vitro study

INTRODUCTION

In India and around the world, dental caries is still an alarming yet preventable oral health concern. According to the World Health Organization’s 2019 Global Burden of Disease Study, two billion adults and 520 million children have caries in their permanent teeth and primary teeth, respectively.^[1] Dental caries is a chronic disease with multifactorial etiology, caused mainly due to imbalance between demineralization and remineralization. Certain bacteria in oral biofilm that can demineralize teeth in specific conditions within the oral cavity cause a carious lesion.^[2] There is no single causative mechanism for dental caries, which is regarded as a “complex” or “multifactorial” disease. As a result, prevention does not rely only on one preventative strategy, such as eradicating germs, controlling nutrition, or changing behavior.^[3]

In modern dentistry, the demineralization-remineralization structure of caries initiate focuses a strong emphasis on the remineralization of carious lesions. To encourage the remineralization of the demineralized enamel, remineralizing agents in a broad range of formulations have been created in the current era of minimal intervention dentistry.^[4] The most traditional and popular remineralizing agent is fluoride. Regarding caries prevention and remineralization, the effects of fluoride treatment alone are limited.^[5] The fact that fluoride loses effectiveness below a pH of approximately 4.5, that it still requires bioavailable forms of Ca²⁺ and PO₄³⁻ ions in saliva and other sources, and that fluoride remineralization of initial lesions is most effective at the outer 30 μm of the lesion, may be linked to these limitations, these results in surface-zone remineralization at the expense of the lesion body, making full remineralization challenging to achieve.^[6,7] Safer methods of remineralizing enamel were required due to concerns about fluoride toxicity, questionable effectiveness, and its adverse consequences.^[8] Newer methods of remineralization include synthetic hydroxyapatite (HAP), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), resin infiltration, ACP, and calcium sucrose phosphate.^[5]

The way the CPP-ACP tooth remineralization process works is by creating an amorphous reservoir of free calcium and phosphate ions in the plaque at the tooth surface. This reservoir keeps the enamel surface in a super-saturation mineral state. CPP and CPP mixed with probiotics showed an antibacterial effect.^[9] The chemical makeup of HAP is comparable to that of the apatite crystals found in human enamel, making it a bioactive and biocompatible substance.^[10,11] Based on its proven capacity to firmly adsorb to tooth surfaces, plaque constituents, and bacteria, a number of in vitro and in situ investigations have offered proof of HAP’s potential for caries remineralization and prevention in oral care products.^[12] Moreover, the nano-HAP and nano-silver combination experimental toothpaste have been reported with both remineralization and antibacterial effects.^[1] Three essential ingredients calcium, sucrose, and phosphate combine to form calcium sucrose phosphate. Calcium sucrose phosphate supplies significant levels of soluble calcium and phosphate ions. It is made up of 85% calcium salts of phosphoric acid esters of sucrose and 15% inorganic calcium orthophosphate by weight.^[13] Along with remineralization potential, if the dentifrice has antimicrobial property, it will be helpful in preventing dental caries in multifactorial method. The null hypothesis was proposed with no difference in antimicrobial efficacy among the study groups. Hence, the aim of this study was to evaluate and compare the antimicrobial efficacy of three remineralizing tooth pastes.

MATERIALS AND METHODS

The three remineralizing toothpastes tested were Shy-NM tooth paste containing Novomin, Enafix containing calcium sucrose phosphate, and Tooth Mousse containing CPP-ACP [Table 1]. A wild Streptococcus mutans strain obtained from dentinal caries was used for the antibacterial assessment. The isolated strain was cultured in Mutans Sanguis Agar (Hi media) at 37°c for 24 h. The cultured strains were suspended in Mueller–Hinton broth and adjusted to 1 × 10⁸ colony-forming units/mL concentrations approximately. The antibacterial activity of the agents was tested by agar well diffusion method. With help of sterile cork well borer, three wells were created in agar plate one and two wells were created in agar plate two. 250 mg of three experimental groups were introduced into wells of plate respectively and in plate two triclosan positive control and distilled water negative control were added. The plates were left for agents to diffuse. Then, the plates were inoculated with 0.5 mL of 24 h broth culture of S. mutans by lawn culture-incubated at 37°c for 48 h. All the plates were made in triplicates. After incubation period, the antibacterial activity was evaluated by measuring the diameter of zone of inhibition.

RESULTS

The mean score and standard deviation of zones of inhibition [Table 1] show that Group B calcium sucrose phosphate agents showed maximum zone of inhibition, followed by control triclosan, Group A Novomin, and Group C CPPACP [Figures 1 and 2]. Group A and Group B are statistically significant than Group C.

Close

Figure 1:

Zone of inhibition experimental groups.

Export to PPT

Close

Figure 2:

Zone of inhibition control groups.

Export to PPT

DISCUSSION

Dental caries is the most common oral disease among the world, which is initiated by certain bacteria that demineralize the tooth and form cavitation.^[14] Dental Caries can be prevented with many strategies such as antimicrobial agents, remineralization, and diet modification. Dental caries is initially formed by the demineralization actions of the toxins produced by bacteria, resulting in the initial stage of white spot lesions. Recent trend of minimal invasive dentistry lots of newer remineralization agents have been introduced.^[15] The present study was conducted to evaluate antibacterial efficacy of different remineralizing agents. Blood Mueller–Hinton agar was used instead of standard Mueller–Hinton agar for testing fastidious organisms like Streptococcus that require additional growth factors, which are supplied by the added blood. The remineralizing agents if have antimicrobial action will act in two ways for preventing dental caries. In the present study, calcium sucrose phosphate group had maximum antimicrobial action than Novomin and CPP-ACP group. Calcium sucrose phosphate effectively hinders the development of dental plaque, a favorable outcome as plaque can serve as a breeding ground for acid producing bacteria, resulting in demineralization. The antibacterial activity of calcium sucrose phosphate has been already reported in previous studies which may be due the neutral pH which does not support growth of S. mutans.^[16] Calcium sucrose phosphate successfully prevents dental plaque from forming, which is beneficial because plaque can act as an ideal environment for bacteria that produce acid, which causes demineralization.^[13]

Bioglasses have been already reported for its antibacterial activity against Microbes. The Novomin bioglass has expressed antimicrobial activity against the S. mutans biofilm in the previous researches. The antibacterial property is due to alkaline ion release and resulting in increased pH. Furthermore, it involves in doping of cations such as Ag, Mg, Sr, and Zn, which also provides antibacterial activity against S. mutans and Lactobacillus.^[17] Instead of directly killing bacteria, CPP-ACP has some antibacterial qualities that are mainly associated with its capacity to disrupt bacterial adherence and formation of biofilm.^[18] It is especially well-known for lowering the levels of S. mutans, a major causative agent of dental caries.

CONCLUSION

Within the limitations like the study are in vitro with tested against single species not the biofilm, it can be concluded that all the remineralizing agents used in the study showed some antibacterial activity against S. mutans. Calcium sucrose phosphate and Novomin had better antimicrobial activity than CPP-ACP. The remineralizing agents with antibacterial effect will help in dual action in preventing dental caries.