A Positive or Negative Connection of Diabetes Mellitus to the Oral Microbiota.

Common noncommunicable diabetes mellitus disease has many complications in several parts of the human body. The oral cavity is one of the areas affected by diabetes mellitus conditions. The most common complications of diabetes mellitus in oral areas include increased drying of the mouth and increased oral diseases resulting from either microbial activity, such as dental caries, periodontal diseases, and oral candidiasis, or physiological problems, such as oral cancer, burning mouth syndrome, and temporomandibular disorders. Diabetes mellitus also has an impact on the diversity and quantity of oral microbiota. Oral infections promoted by diabetes mellitus mainly result from disturbance of the balance between different species of oral microbiota. Some oral species may be positively or negatively correlated with diabetes mellitus, while others may not be affected at all. The most numerous species in the presence of diabetes mellitus are those of phylum Firmicutes of bacteria such as hemolytic Streptococci, Staphylococcus spp., Prevotella spp., Leptotrichia spp., and Veillonella and species of the fungus Candida. Proteobacteria spp. and Bifidobacteria spp. are common microbiota that are negatively impacted by diabetes mellitus. In general, the effect of diabetes mellitus could include all types of oral microbiota, whether it is bacteria or fungi. The 3 types of association between diabetes mellitus and oral microbiota that will be illustrated in this review are increase, decrease, or lack of impact. As final inclusion, a great number of oral microbiota have increased in the presence of diabetes mellitus.