"Periodontal disease is the number one health problem in small animal patients. By two years of age, 70% of cats and 80% of dogs have some form of periodontal disease. However, there are generally little to no outward clinical signs of the disease process, and therefore, therapy typically comes very late in the disease. Consequently, periodontal disease may also the most undertreated disease in our patients. Additionally, unchecked periodontal disease has numerous local as well as systemic consequences. Local consequences include: oronasal fistulas, class II perio-endo lesions, pathologic fractures, ocular problems, osteomyelitis, and increased incidence of oral cancer. Systemic diseases which have been linked to periodontal disease include: renal, hepatic, pulmonary, and cardiac diseases; osteoporosis, adverse pregnancy effects, and diabetes mellitus. Finally, periodontal disease leads to early death."
Above quoted from Brook A. Niemiec DVM (Diplomate, American veterinary Dental College). Thank you Dr. Niemiec!