<p>Plant-based essential oils are widely used as natural products and remedies for the prevention and treatment of various diseases such as dental caries and periodontal disorders. In this paper, we reviewed some clinical, in vivo, and in vitro investigations on therapeutic effects of eighteen essential oils on dental caries and periodontal diseases. The essential oils of clove, thyme, black seed, and cinnamon had the most preventive and therapeutic properties. The essential oils (terpenoids) can disrupt cell membrane function of microbial in the dental and gum disorders by binding hydroxyl groups to membrane proteins. Moreover, the essential oils of clove, garlic, lemongrass, cinnamon, thyme, cardamom, chamomile, and yarrow had the highest antioxidant and anti-inflammatory activities. These natural constituents can inhibit the inflammatory cytokines production, NF-κB signaling pathway, and activity of COX-2 enzyme. In conclusion, the essential oils can be useful for sustaining optimal health and maintaining antioxidant, antimicrobial, and anti-inflammatory activities.</p>