Antimicrobial Effect of Curcumin Versus Chlorohexidine on Oral Microbiome

Dental caries, one of the world's most common infectious diseases, is a biofilm-mediated, sugar-driven, dynamic disease. It has an impact on physical, mental, and social health and is extremely costly to society. It is a complex disease with microbiological, behavioral, genetic, and environmental components. Recently, it has been demonstrated in the literature that the development of dental caries is strongly related with the microbiota in the oral cavity. So, a detailed understanding of caries microbiology is needed.

Oral microbiome, oral microbiota or oral microflora refers to the microorganisms found in the human oral cavity that was first identified by the Dutchman Antony van Leeuwenhoek using a microscope constructed by him. In 1674, he observed his own dental plaque and reported "little living animalcules prettily moving".

Human microbiome consists of a core microbiome which is common to all the individuals and a variable microbiome that is unique to individuals depending on the lifestyle and physiological differences. Dental caries, as a process determined by lifestyle, may be subject to activation in each period of human life if hygiene and diet are neglected even for a period as short as a few weeks.

Previous hypotheses suggest that Streptococcus mutans is the primary pathogen in the development of dental caries in both children and adults. However, recently published papers provide a partially different perspective on the role of bacteria in the caries process, known as the "extended caries ecological hypothesis," which attempts to demonstrate that the role of S. mutans in the initiation of dental caries may not be as dominant as previously assumed, but there is agreement that they have the highest cariogenic potential.

It is now believed that the disease is caused by microorganisms belonging to the natural flora of the oral cavity: the oral microbiome. There is a dynamic equilibrium between microorganisms as well as between the micro flora and the 7 host, and the disease develops as a result of a microbiological imbalance within the biofilm.

Therefore, a better understanding of processes of oral biofilm formation and function is necessary to the development of novel, successful, rational approach for antimicrobial strategies and caries prevention and treatment.

Primary caries can be prevented, stopped and treated by regular plaque removal and remineralization mechanisms. Fluorides play a central role in the prevention of dental caries and are being used extensively and therapeutically for the inactivation of incipient carious lesions. However, regarding the high cost of dental clinic setting and difficult access to the oral health care service that is not well-covered in certain countries; the treatment strategy should move towards the preventive, simple, accessible, less costly methods.

The frequent use and abuse of the currently used therapeutic agents has led to the evolution of resistant strains of common pathogens as well as increased incidence of adverse effects associated with their usage. Therefore, natural phytochemicals extracted from plants used as traditional medicines are therefore seen as a good alternative source.

Pharmaceutical plants have been used throughout human history to treat a variety of diseases. According to the World Health Organization, almost 80% of the world's population relies on traditional medicinal plants for primary health care. In dentistry, there is a growing need to develop natural materials with anti-caries qualities.

Curcumin (CUR), a dietary natural product extracted from the root of turmeric (the major constituent of Curcuma longa L. or turmeric), which is widely used as a flavoring and coloring agent has many pharmacological activities including anti-inflammatory and antitumor properties. In addition, CUR has been shown to have anti-bacterial, whitening, and antioxidative activities. Various studies on widespread Polyphenolic compounds suggest that curcumin inhibits the bacterial effect by reducing the production of acid and stopping the adherence of bacteria to the tooth surface. Song et al. found that curcumin could significantly inhibit the adhesiveness of S. mutans by its effects on collagen and fibronectin. The antibacterial action of curcumin involves the disruption of the bacterial membrane, inhibition of the production of bacterial virulence factors and biofilm formation, and the induction of oxidative stress. These characteristics also contribute to explain how curcumin acts a broad-spectrum antibacterial adjuvant. So, the aim of the following interventional study is to evaluate the effect of curcumin on oral microbiome obtained from salivary samples of high caries risk patients in vitro and assess the antiplaque and anticariogenic effect of curcumin mouth wash in high caries risk patients in a randomized controlled clinical trial compared to chlorohexidine mouth wash.