Periodontal Disease in Dogs and Cats
Sandra Manfra Marretta, DVM, Diplomate
Periodontal disease is probably the most common disease affecting dogs and cats today.1 Therefore, it is important for the veterinary technician to have a thorough working knowledge of the pathophysiology associated with periodontal disease, recognize the various stages of periodontal disease, and be able to assist in the various treatment modalities of periodontal disease.
Pathophysiology of Periodontal Disease
Periodontal disease increases significantly with increasing age, and decreases significantly with increasing body weight and is particularly obvious when comparing toy and small dogs with medium and large dogs.2 Periodontal disease is caused by an accumulation of bacteria in the form of plaque on the surface of the teeth which results in gingival inflammation. If left untreated this results in a predominant flora change from a gram-positive aerobic coccoid bacteria to a more motile, gram-negative, anaerobic, rod-shaped bacteria, which results in further destruction of periodontal tissues which in turn can result in clinically significant local and systemic problems.
Stages of Periodontal Disease
There are two broad categories of periodontal disease. Gingivitis is the early form of periodontal disease in which inflammation is confined to the gingival soft tissues. Periodontitis is the more established form of periodontal disease in which the supporting bone recedes, the tooth becomes loose and may eventually be lost if the periodontitis is left untreated.
Animals that have Stage I (gingivitis) periodontal disease have gingivitis with no attachment loss. Some dogs may have significant dental calculus with minimal gingivitis while others may have severe inflammation with minimal plaque and calculus. This stage of periodontal disease results in inflammation, edema, plaque and calculus accumulation, possible bleeding on probing, and pseudopockets may be present.3 Animals with Stage II (early) periodontal disease, have periodontal probing and dental radiographics that may indicate attachment loss of up to 25% with the teeth remaining stable. Horizontal bone loss often occurs prior to vertical bone loss in this stage of periodontal disease.3 Animals with Stage III (moderate) periodontal disease, have probing and radiographic signs of attachment loss between 25% and 50% of the root length. In this stage of periodontal disease vertical defects and infrabony pockets may be present and teeth may begin to become mobile.3 Animals with Stage IV (severe) periodontal disease have attachment loss greater than 50%. In this stage of periodontal disease there is severe loss of supporting tooth structures and teeth become loose. There may be significant infrabony pockets localized to a single area.3
Treatment Modalities of Periodontal Disease
There are numerous treatment modalities associated with the management of periodontal disease. These treatment modalities include: supragingival and subgingival scaling, root planing, subgingival curettage, polishing, irrigation, perioceutics, exodontia, oronasal/oroantral fistula repair, and home care. Prior to administration of various treatment modalities for periodontal disease a thorough assessment of the patientís general health stasis is mandatory. Many animals with periodontal disease may have concurrent problems including diabetes, cardiopulmonary problems, hepatic, renal, and other metabolic problems. Once these diseases are recognized and managed appropriately, anesthetic protocols can be selected based on the individual patientís requirements.
Accurate charting with the patient anesthetized will help in the systematic evaluation of the periodontal disease. A periodontal probe properly utilized can accurately assess attachment loss associated with periodontal disease. The periodontal probe is placed perpendicular to the gingival margin and gently inserted parallel to the long axis of the tooth to the bottom of the sulcus or pocket. The probe is "walked" around the entire wall of the tooth, measuring the depth of the sulcus or pocket in at least six places around the tooth. In questionable areas a dental radiograph may be taken for further evaluation of the level of attachment loss. These findings should be recorded on the patientís dental chart for future reference.
Various types of power scalers have been utilized in the removal of dental calculus. Four different power scalers have been utilized including: the ultrasonic piezoelectric scaler, ultrasonic magneto-strictive scaler, sonic scaler, and rotosonic scaler. Both ultrasonic scalers are efficient in the removal of dental calculus. The ultrasonic magneto-strictive scaler produces a significant amount of heat when scaling and should be moved quickly across the tooth surface with adequate water flow to avoid pulpal injury from excessive heat production. The sonic scaler is less efficient in the removal of calculus than the ultrasonic scalers but like the ultrasonic piezoelectric scaler does not produce excessive heat. The rotopro scaler is the least efficient in the removal of dental calculus, produces a significant amount of heat, and is severely damaging to the enamel surface, capable of producing deep groves in the enamel based on electron microscopic studies and is not recommended for the routine removal of dental calculus.4
Prior to ultrasonic scaling the patientís mouth is lavaged with a 0.12% chlorhexidine solution to reduce external bacterial counts. Gross calculus is gently removed with an extraction forceps by gently closing the forceps across the calculus. A power scaler is used to remove the remaining plaque, calculus, and debrie. Adequate water flow is essential when using power scalers to cool the oscillating tip and flush away the debris. The side of a sickle-shaped scaling tip is placed on the tooth surface and moved lightly and continuously over the tooth surface. Continuous scaling of any one tooth for more than 15 seconds must be avoided to prevent pulp tissue injury from excessive heat and potential production of subsequent pulpal necrosis.
Subgingival scaling removes debris that has accumulated below the gingival margin which causes inflammation of the supporting structures of the teeth. Failure to remove subgingival calculus promotes the progression of periodontal disease. Subgingival calculus is removed with a curette. The instrument is inserted with the face of the blade flush against the tooth. When the instrument reaches the bottom of the pocket the working angulation of the instrument, usually 45 degrees, is established. The instrument is then pushed against the tooth and pulled coronally. This process is repeated until all subgingival calculus is removed.
Root planing is the smoothing of the root surface using curettes. This procedure is not a distinct entity from subgingival scaling or cleaning of the root surfaces but rather a continuation of the process. When the root is adequately planed it should feel smooth and hard like glass. Thorough root planing leaves the tooth less susceptible to accumulation of debris, permits adaptation of the gingiva around the tooth and thereby reduces mechanical retention areas where calculus may become lodged.
Subgingival curettage is the removal of diseased soft tissue from the periodontal pocket. While one edge of the curet engages the root surface, the other edge engages the soft tissues of the periodontal pocket. Although this process is often not thought of as a deliberate procedure it removes the diseased soft tissue portion of the periodontal pocket.
After the removal of all calculus the teeth are polished with a rubber cup placed on a prophylaxis angle attached to a slow-speed handpiece. Prophy paste is placed on the teeth and the cup is rotated over all tooth surfaces at a low speed. The cup is then pressed gently but firmly at the gingival margin to permit polishing of the root surface adjacent to the crown. Polishing the teeth smooths out the rough areas caused by the scaling procedure. Production of excessive heat during polishing must be avoided by using adequate paste, not applying excessive pressure and avoiding continuous polishing of one tooth for more than 15 seconds. Utilization of proper polishing techniques will prevent the development of pulpal necrosis.
After polishing, the gingival sulcus is irrigated with a 0.12% chlorhexidine solution using a blunted 23-gauge needle and a 12 ml syringe. Irrigation of the gingival sulcus removes loose calculus, prophy paste and debris and reduces the bacterial counts.
Perioceutics are pharmaceutical formulations that are placed into or near the gingival sulcus or pocket around a tooth to provide some form of treatment for periodontitis and periodontal disease, resulting in some degree of periodontium rejuvenation.4 Local perioceutics are a flowable doxy- cycline solution that is applied directly into the periodontal pocket of dogs by the use of a syringe and blunt-tipped periodontal needle. This form of therapy allows for treatment of periodontal disease by the direct placement of the product into the affected area. Following placement of the solution into the gingival sulcus the solution coagulates and forms a firm gel that can be packed as it solidifies to fill the pocket more completely.5 Placing a finger over the gingival sulcus prior to removal of the needle helps prevent premature removal of the perioceutic. The objective of this form of treatment is to provide local treatment of the periodontal pocket for 2-3 weeks. This type of therapy may be particularly beneficial in dogs with painful oral ulcers in which home care may not be possible.
Exodontia is that portion of dentistry that deals with the extraction of teeth. The most common indication for exodontia in the dog is advanced or Stage IV periodontal disease. Teeth with less than 20-30% of remaining bone height have a poor prognosis. Dogs can manage well without teeth, in fact dogs with very severe periodontal disease are better off without teeth because loss of diseased teeth is the most dependable way to eliminate this source of chronic infection.1 However, teeth should be retained whenever practical for functional and aesthetic reasons. It is recommended that occluding pairs of teeth particularly the carnassial teeth or the canine (and maxillary third incisor) teeth be retained as functional units whenever practical.
Extraction is recommended in those teeth in which the periodontal pocket has reached the apex of at least one root of a multirooted tooth. Animals with Stage III or moderate periodontal disease in which the client is unwilling or unable to provide appropriate periodontal care may be candidates for exodontia rather than advanced periodontic treatment regimens. Also those animals that may not be good candidates for multiple anesthetic episodes, or have severe mucogingival disease may benefit from exodontia versus advanced periodontic therapeutic techniques. Owner preference should also be considered when determining the most appropriate treatment protocol for a particular patient.
Oronasal and oroantral fistulas are most frequently caused by advanced periodontal disease. Signs associated with oronasal and oroantral fistulas include sneezing and mucopurulent or hemorrhagic nasal discharge. The most common location of oronasal fistulas in the dog is the palatal aspect of the maxillary canine tooth. Other teeth that can potentially cause oronasal fistulas are the maxillary incisors and first three premolars. Oroantral fistulas may be associated with advanced periodontal disease of the distal root of the third premolar, fourth premolar, and first molar. Teeth affected with Stage IV periodontal disease should be removed and the oronasal or oroantral fistula should be repaired with a mucoperiosteal flap.
A single-layer flap is recommended for the repair of most fistulas. Initially a thin layer of mucosa is removed from the perimeter of the fistula thereby removing the entire epithelial edge of the fistula with a #15 blade. Divergent incisions are made from the mesial and distal aspects of the fistula through the mucogingival line extending into the alveolar mucosa. The mucoperiosteal flap is gently elevated using a periosteal elevator. The mucoperiosteal flap is retracted laterally and apically to expose the periosteum of the apical region of the flap. The periosteal layer of the flap is incised distomesially in the apical region to improve flap mobility. The flap is positioned over the fistula to ensure that there is no tension on the flap prior to closure. The mucoperiosteal flap is sutured to the palatal and gingival mucosa with a simple interrupted pattern using 3-0 or 4-0 absorbable monofilament suture material such as Monocryl on a reverse cutting needle.
Home care following periodontal therapy is an important part in the treatment and prevention of periodontal disease. There are several aspects of home care that need to be recommended following periodontal therapy including: antibiotic therapy, administration of analgesics, tooth brushing with dentifrices, chemical plaque control, and dietary/chew toys to reduce plaque and calculus formation.
Systemic antibiotics are not recommended for the routine prevention of periodontal disease, nor are they recommended in animals undergoing routine scaling of healthy dogís teeth without periodontitis.6 However, perioperative antibiotics are recommended in animals with moderate to severe periodontitis, patients with painful oral ulcerations, animals who do not receive any home oral hygiene, those with systemic disease that may be worsened by bacteremia (turbulent blood flow caused by heart valve lesions or chronic renal failure), and patients undergoing concurrent clean or clean-contaminated surgical procedures.6 The antimicrobial of choice for clinical use in dogs and cats with periodontal disease based on susceptibility testing is amoxicillin-clavulanic acid (Clavamox: Pfizer),7 a preparation comprised of the broad-spectrum antibiotic amoxicillin and the B-lactamase inhibitor clavulanate potassium for 2-14 days perioperatively depending on the severity of periodontal and individual patientís requirements. Perioperative antibiotics should be administered so that a therapeutic blood level is obtained prior to induction of the bacteremia caused by the dental therapy.6
Analgesics are recommended perioperatively in the treatment of periodontal disease. Injectable premedicants such as medetomidine, butorphanol or morphine can be administered preoperatively to provide preemptive analgesia. Additionally, carprofen (Rimadyl: Pfizer) a non-narcotic, nonsteroidal anti-inflammatory drug can be administered perioperatively in dogs to relieve pain and inflammation associated with dental procedures. Carprofen may be started one day prior to the dental procedure and continued as needed postoperatively. This drug is not recommended in dogs with gastrointestinal, renal or hepatic problems. The dose is 2mg/kg orally every 12 hours.
Tooth brushing can be accomplished utilizing an appropriately sized tooth brush with soft bristles. The tooth brush with a small amount of pet dentifrice is placed at a 45 degree angle to the gingival sulcus and gently rotated to remove plaque from the sulcus. Chemical plaque control, in the form of chlorhexidine gluconate gel, can assist also in the reduction of plaque and gingival inflammation.
Chewing specially formulated dry food and treats has been shown to decrease calculus formation in pets. The first specially formulated dental diet in dogs, Hillís Prescription Diet, Canine T/D, is effective in the reduction of plaque, stain and calculus in dogs.8 Other diets and treats have also been shown to be effective in the reduction of plaque, stain and calculus in dogs.
(1) Harvey CE: Periodontal disease in dogs: Etiopathogenesis, prevalence, and significance. Vet Clin North Amer: Small Anim Pract 28:1111-1128, 1998.
(2) Harvey CE, Shofer FS, Laster L: Association of age and body weight with periodontal disease in North American dogs. J Vet Dent 11:94-105, 1994.
(3) Wiggs RB, Lobprise HB: Periodontology. In: Wiggs RB, Lobprise HB, eds. Veterinary Dentistry Principles & Practice. Philadelphia: Lippincott-Raven, 1997: 186-231.
(4) Manfra Marretta S: Comparison of the efficacy of four different power scalers in the removal of dental calculus in the dog. J Vet Dent 11(3):111, 1994.
(5) Wiggs RB, Lobprise H, Mitchell PQ: Oral and periodontal tissue maintenance, augmentation, rejuvenation, and regeneration. Vet Clin North Amer: Sm Anim Pract 28(5):1165-1188, 1998.
(6) DuPont GA: Prevention of periodontal disease. Vet Clin North Amer: Small Anim Pract 28:1129-1145, 1998.
(7) Harvey CE, Thornsberry, Miller BR, Shofer FS: Antimicrobial susceptibility of subgingival bacteria flora in dog with gingivitis. Jour Vet Dent 12:4, 1995.
(8) Jensen L, Logan E, et al: Reduction in accumulation of plaque, stain, and calculus in dogs by dietary means. J Vet Dent 12(4):161-163,1995.