Which type of microorganism predominates in the human mouth?

The human mouth is home to a diverse array of microorganisms, but bacteria are the predominant type. Within the oral cavity, thousands of bacterial species coexist, forming complex biofilms known as dental plaque. These bacteria play various roles, including the process of oral health and disease.

The oral environment provides a niche rich in nutrients, particularly from food residues, which supports a robust bacterial population. Some of these bacteria are beneficial, contributing to the prevention of pathogens and aiding in digestion, while others can be pathogenic, leading to conditions like dental caries and periodontal disease when they proliferate beyond normal levels.

In contrast, while fungi and protozoa are also present in the mouth, they are not as numerous or predominant as bacteria. Viruses can infect oral bacteria or reside in the mouth as well, but again, they do not dominate the microbial landscape as bacteria do. Therefore, the correct answer highlights the critical role of bacteria in the oral microbiome.