Periodontal disease is the most prevalent oral condition in companion animals, affecting over 80% of dogs and cats by three years of age. Despite its high incidence and systemic health implications, it is frequently underdiagnosed and undertreated in veterinary practice. This review addresses the pathophysiology, diagnostic tools, and provides evidence-based strategies for prevention and management of periodontal disease in dogs and cats. The review explores the anatomy and physiology of the periodontium and details the mechanisms of disease progression, particularly the role of bacterial biofilm and host immune response. A focus is placed on the RANK/RANKL/OPG signaling pathway, which governs osteoclast-mediated bone resorption, a hallmark of advanced periodontitis. Risk factors such as age, diet consistency, and breed size are examined in relation to disease susceptibility. Current best practices in prevention, including daily tooth brushing, dental chews, antiseptic rinses, barrier sealants, and mechanical debridement, are reviewed alongside emerging therapies such as ozone treatment and regenerative procedures using platelet-rich fibrin, synthetic bone grafts and hyaluronic acid.