A review.Depending mainly on the diet and the frequency of toothbrushing, a dental plaque may appear.Dental plaque may consists in a thin biofilm of bacteria (like Streptococcus mutans, Lactobacilli), bacterial products, salivary proteins, and food substances from the diet.Between two toothbrushings, bacteria naturally present in the saliva develop and contribute to plaque formation.Dental plaque formation is common.Normally, the dental plaque is not visible to the naked eye but if it is not regularly removed by toothbrushing, it may become thick enough to be seen and may mineralize to form tartar.