Dental (or periodontal) health is vital to the overall health of dogs, cats, and wild animals. Without teeth, survival of the animal is particularly challenging. Wild animals may succumb to starvation and pets may require special diets tailored for their chewing needs. Awareness of dental anatomy, disease progression, and dental care options build a foundation for better dental health thus promoting optimal health of an animal.
The oral cavity is divided into two halves: the upper jawbone known as the maxilla and the lower jawbone known as the mandible. The upper teeth are called maxillary teeth and the lower teeth are called mandibular teeth. The mouth is further divided into four quadrants: right maxillary, left maxillary, right mandibular, and left mandibular.
The oral cavity of the adult dog is comprised of 42 teeth total: 12 incisors, 4 canines, 16 premolars, 2 top molars, and 3 lower molars. Adult cats contain 30 teeth: 12 incisors, 4 canines, 3 top premolars, 2 lower premolars, and 4 molars. Immature dogs and cats have deciduous or baby teeth which will be shed to make room for the eruption of adult teeth. Some breeds of dogs are more apt to retain baby teeth that may contribute to plaque accumulation and development of progressive periodontal disease.
There are 4 types of teeth each with different shapes and functions. The first type is the incisor which are the small teeth in front of the mouth. They cut, tear, and groom. The second type is the canine tooth which are the longest most pointed teeth; sometimes referred to as the eye tooth, fang or vampire tooth. Canine teeth are used for grasping, heavier tearing and fierce biting for defense. The third type of tooth found in the oral cavity is the premolar. Premolars are sharp pointed teeth used for cutting and shearing food. The fourth and final type of tooth is the molar which has a flat surface used for crushing and grinding.
The structures around each tooth comprise the periodontium. The periodontium is made up of the gingiva (gum tissue), periodontal ligament (fibers that secure a tooth in the jaw), cementum (covering the root and provides a base for the periodontal ligament to attach), and alveolar bone (forms the tooth socket).
Dental disease is commonly referred to as periodontal disease and refers to the tooth plus the surrounding structures. According to the World Small Animal Veterinary Association (WSAVA) Global Dental Guidelines, dental disease is the most important condition affecting animals in veterinary practice.1 Furthermore, American Animal Hospital Association (AAHA) states that by 2 years of age, approximately 80% of dogs and 70% of cats have some form of periodontal disease.2 Contributing factors to dental disease include but are not limited to anatomical issues such as tooth crowding, malocclusion, concurrent disease like diabetes, kidney disease, FIV, FeLV, and diet. These factors contribute to periodontal disease by promoting plaque (bacteria) formation or altering the immune response to plaque. It is crucial to understand that periodontal disease can be a silent killer as few signs are seen until the disease has advanced. A majority of pets with dental or periodontal disease show no signs of disease. Plaque, the precursor to more advanced periodontal disease, is not always visible.
Periodontal disease has two distinct phases: Gingivitis and Periodontitis. Gingivitis describes inflammation of the gingiva or gum tissue. During this stage, there is no attachment or bone loss at or below the gumline. Gingivitis is considered reversible with proper care and is called Stage 1 of Periodontal Disease. As gingivitis worsens and bacteria continues to accumulate above and below the gumline, periodontitis forms. Periodontitis is inflammation of the non-gingival tissue surrounding the tooth and is considered irreversible but can be managed through intensive and consistent dental care. Periodontitis is initiated by the following; adherence of plaque to the tooth, formation of tartar or calculus (accumulation of plaque) moving below the gumline toward the root, inflammation created by bacteria and its’ byproducts, the animal’s inflammatory and immune response, and finally attachment and bone loss. Attachment loss refers to the formation of a periodontal pocket from plaque and tartar moving toward the root of the tooth causing pockets. Gingival recession describes receding of the gum tissue from around the tooth, bone loss will develop. Periodontitis is recognized as Stages 2, 3, and 4 of Periodontal Disease directly related to the amount of inflammation, attachment, and bone loss present in the oral cavity.
How does dental disease progress to systemic or whole body disease? Plaque migrates from above the gumline (supragingival) to below the gumline (subgingival) where the underlying structures supporting the tooth become infected. Gingivitis leads to further inflammation and infections. The inflammation produced increases permeability of the vasculature, this allows access of bacteria and its’ by-products to the blood. The immune system is stimulated by the tissue inflammation and invasion of bacteria into the bloodstream (bacteremia). The bacteremia circulates throughout the body affecting the heart, kidney, and liver. Symptoms of periodontal disease may go unnoticed as plaque and gingivitis may not be visualized. Bad breath may be the only symptom evident of periodontal disease as well as other conditions. As periodontal disease progresses, the pet may show signs of pain such as pawing at the face, eating food on one side of the mouth, dropping kibble while trying to eat, or refusing to eat diet or treats.
Since evaluating for periodontal disease can be difficult in an awake animal, there is a test available that detects thiol production by obtaining a sample of crevicular fluid (gingival fluid) from the gingival margin (tooth and gum junction). Thiols compose part of the by-products released by subgingival bacteria and may not be produced continuously. Thiol production can undergo quiet phases although dental disease is present. This thiol detection test provides insight without invasive probing and is performed painlessly and quickly during a veterinary visit. The best way to evaluate for periodontal disease in addition to physical examination is measuring pocket formation in an anesthetized animal.
Professional intervention may be warranted despite the best of home care. Professional intervention may be referred to as a dental prophylaxis, prophy, dental cleaning, or simply a dental and requires the animal to be anesthetized. Dental prophylaxis involves a series of steps: 1) evaluation of the oral cavity for abnormalities; 2) measuring of pockets between the tooth and gum tissue illustrating structural damage; 3) the removal of plaque and tartar or calculus; 4) the polishing of each tooth to negate enamel damage; 5) irrigation of the structures below the gumline; and 6) the application of anti-plague substances for protection. Dental radiographs are performed as part of the procedure to further monitor structural health below the gumline.
Dental care is a priority starting early in the animal’s life and remaining throughout their adult life. Home care consists of brushing the teeth, giving dental chews daily designed to clean the teeth, or using water additives formulated to interact with water providing some action against plaque formation. The goal of these various preventative methods is to reduce plaque (and tartar if labeled), freshen breath, and protect the periodontal tissues from damage caused by plaque accumulation. Annual examination of the oral cavity is recommended.
The WSAVA Global Dental Guidelines and AAHA Dental Guidelines for Dogs and Cats are reliable sources for additional information regarding oral health and your pet.
1. World Small Animal Veterinary Association (WSAVA): Global Dental Guidelines. <https://www.wsava.org/Guidelines/Global-Dental-Guidelines> (Accessed 31 August 2018).
2. American Animal Hospital (AAHA); Dental Guidelines for Dogs and Cats. 2013. https://www.aaha.org/public_documents/professional/guidelines/dental_guidelines.pdf> (Accessed 31 August 2018).