Recognition and Treatment of Periodontal Disease

Sandra Manfra Marretta, DVM, Diplomate ACVS, AVDC
University of Illinois

Periodontal disease is probably the most common disease in dogs.¹ Most dogs greater than 5 years of age have significant periodontitis. 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 the accumulation of bacteria in the form of plaque on the surface of the teeth which results in gingival inflammation and if left untreated results in the destruction of periodontal tissues which can result in clinically significant local and systemic problems.

Periodontal disease occurs in two forms gingivitis and periodontitis. Gingivitis is a reversible inflammation of the gingiva. Periodontitis involves deeper inflammation with loss of tooth support and permanent damage. The purpose of periodontal therapy is to prevent gingivitis from progressing to periodontitis and to delay the progression of periodontitis once it is established.

Periodontal disease is initiated by an accumulation of large amounts of bacteria at the junction of the tooth and the gingiva. Prolonged retention of these bacteria results in a change of the predominant flora from a gram-positive aerobic coccoid bacteria to a more motile gram-negative anaerobic rod-shaped bacteria. Mixed aerobic-anaerobic flora are commonly found in animals with periodontal disease. Also important in the development of periodontal disease is the consumption of large quantities of oxygen by aerobic bacteria. As the number of bacteria increases, the oxygen concentration becomes low, especially in the periodontal pockets, creating an environment favorable for the growth of anaerobic bacteria. Because a mixed aerobic-anaerobic flora is associated with periodontal disease a broad spectrum antibiotic is recommended in the perioperative period as part of the treatment regimen for significant periodontal disease.

A recent in vitro study compared the antimicrobial susceptibility of canine subgingival isolates to commonly used antibiotics in periodontal disease including amoxicillin-clavulanic acid, cefadroxil, clindamycin, and enrofloxacin³. Amoxicillin-clavulanic acid (Clavamox) was shown to be by far the most effective antimicrobial against canine gram positive and gram negative aerobic and anaerobic isolates with a 96% susceptibility to a total of 359 isolates. The results of this study resulted in the FDA approval of Clavamox for the treatment of canine periodontal disease.

Systemic antibiotics are not recommended for the routine prevention of periodontal disease, nor are they recommended for routine scaling of healthy dogs teeth without periodontal disease.⁴ 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.⁴ The antimicrobial of choice for clinical use in dogs with periodontal disease is Clavamox.³ The length of time recommended for the perioperative administration of antimicrobials varies from 2 to 10 days depending on the severity of periodontal disease. Perioperative antibiotics should be administered so that a therapeutic blood level is obtained prior to induction of the bacteremia caused by the dental therapy.⁴

Treatment of Periodontal Disease

Ideally the prevention of periodontal disease is preferred over the treatment of already established periodontal disease. 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.¹ 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.

The treatment of periodontal disease includes a variety of techniques including: supragingival and subgingival scaling, root planing, subgingival curettage, polishing, gingivectomy, open-flap curettage and augmentation of boney defects, utilization of perioceutics, management of endodontic-periodontic lesions, extraction, oronasal fistula repair, and home care.

Supragingival Scaling

Supragingival scaling refers to the removal of dental calculus above the gingival margin. This is most easily accomplished in small animals utilizing power scalers. In a recent study the efficacy with which four different power scalers (ultrasonic magneto-strictive, sonic, ultrasonic piezoelectric, and rotosonic scalers) removed dental calculus in the dog was compared.⁶ The ultrasonic piezo electric scaler removed calculus significantly faster than all the other power scalers. The ultrasonic magnetostrictive scaler was faster in the removal of calculus than the sonic scaler and the sonic scaler was faster in the removal of calculus than the rotopro scaler. Electron microscopy of teeth scaled were all similar except the teeth that were instrumented with the rotosonic scaler. The surface of the enamel of these teeth contained multiple deep groves.

Prior to ultrasonic scaling the patient�s 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 gently 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

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

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.

Polishing

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.

Irrigation

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.

Gingivectomy

Gingivectomy is the removal of gingival pockets by the excision of gingiva. There are several indications for gingivectomy including the following: gingival hypertrophy or hyperplasia, excisional or incisional gingival biopsy, elimination of shallow supraboney pockets with retention of adequate attached gingiva. A gingivectomy is contraindicated when there is inadequate attached gingiva or horizontal and vertical pockets extend below the mucogingival line. A gingivectomy is performed by measuring the depth of the periodontal pocket and marking the depth of the pocket with the tip of the periodontal probe by pressing it into the gingiva perpendicular to the tooth to create a bleeding point. This is repeated every few millimeters to mark the pocket depth. A No. 15 blade is used to create a beveled incision starting 1 to 3 mm apical to the bleeding points (depending on the thickness of the gingiva) to produce an anatomically correct gingival margin. A 30 to 45 degree angle is recommended.

Open-Flap Curettage and Augmentation of Boney Defects

Open-flap curettage is indicated in cases of periodontal disease in which pockets are greater than 5-6 mm deep and do not respond to conservative therapy. The purpose of flap surgery is to reflect soft tissue and gain access to deeper periodontal structures which can then be more thoroughly treated with the benefit of direct visualization.

The most common indication in dogs for open-flap curettage and augmentation of periodontal boney defects are deep periodontal defects on the palatal aspect of the maxillary canine teeth. Utilization of this technique is not recommended for loose teeth where salvage is not desired, in teeth with severe oronasal fistulation, and in cases with osteomyelitis.

To repair a deep palatal periodontal defect a semilunar flap from the palatal surface of the affected canine tooth is raised four millimeters palatal to the edge of the boney defect. The periodontal pocket is debrided with a currette removing all calculus, granulation tissue, and debris. The area is flushed with 0.12% chlorhexidine solution. A bulk matrix osseous replacement packing material which generally consists of small particulate granules can be placed in the defect in the hopes that they will be incorporated as a matrix into the initial blood clot that is subsequently replaced by supportive tissue, either bone or periodontal ligament, while deterring the ingrowth of gingival epithelium and connective tissue. ⁷ A bulk matrix osseous replacement packing material available in the veterinary market is Consil (Nutramax Labs). After placement of the granules into the defect the palatal gingival flap is sutured in place with 4-0 absorbable suture material such as Monocryl adapting the flap closely to the underlying bone and tooth with as little tension as possible.

The treated palatal defect should be reexamined in 6-12 months. Results are usually good with nearly full closure of the defect in many cases. If the deep periodontal defect or the oronasal communication persists, the defect may be retreated or the canine tooth may be extracted. The oronasal fistula is then closed with a single-layer or double-layer mucoperiosteal flap.

Perioceutics

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.⁷ Local perioceutics are a flowable doxycycline solution that is applied directly into the periodontal pocket of dogs by the use of a syringe and blunt-tip 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. ⁷ The objective of this form of treatment is to provide local treatment of the periodontal pocket for 2-4 weeks. This type of therapy may be particularly beneficial in dogs with painful oral ulcers in which home care may not be possible.

Endodontic-Periodontic Lesions

Endodontic-periodontic lesions have been previously described in the dog.⁸ A tooth categorized as having an endodontic-periodontic lesion must have at least one root in which there is necrotic pulp and there must be destruction of the periodontal attachment extending from the gingival sulcus down to either the apex of the tooth or the area of a lateral canal. A Class I or endodontic-periodontic lesion which is endodontic in origin begins in the pulp and progresses to involve the periodontal tissues. A Class II or periodontic-endodontic lesion which is periodontic in origin begins in the periodontal tissues and progresses to involve the pulp. A Class III or true combined endodontic and periodontic problem is a fusion of independent endodontic and periodontic lesions.

The clinical examination findings of a dog with pathologic problems involving both the periodontium and endodontium will vary depending on the type of lesion. Class I or endodontic-periodontic problems usually present as a fractured tooth with a narrow and difficult to probe drainage canal which exits near the gingival margin. Class II or periodontic-endodontic lesions usually present with a wide pocket that can easily be probed and usually extends down to the apex of one root. Class III lesions or true combined endodontic and periodontic problems usually have evidence of primary pulpal injury such as a fractured tooth with pulpal exposure and a wide easily probed periodontal defect which communicates with the periapical lesion.

The radiographic appearance of pathologic problems involving both the periodontium and endodontium will vary depending on the type of lesion. Class I or endodontic/periodontic problems have a typical "J"shaped lesion. Class II or periodontic-endodontic problems may be difficult to demonstrate radiographically unless there is evidence of periapical lysis in addition to the primary periodontal lesion. Class III lesions or true combined endodontic-periodontic problems usually demonstrate a pronounced periapical lesion secondary to a fractured tooth with a deep wide periodontal pocket.

The initial treatment planning of teeth with endodontic and periodontic lesions should include a determination of whether a tooth can be saved or might be more prudently extracted. In general, the prognosis for Class I lesions are fair to good depending upon the amount of secondary periodontal destruction. The prognosis for Class II and III lesions is generally poor.

Recommendations for treatment planning in dogs with combined endodontic and periodontic pathology can be based on treatment regimens utilized in man with similar pathology. Treatment of lesions in Class I, II, or III is initiated with antibiotic therapy if swelling is present. Teeth are accessed for severity of secondary periodontal destruction. In cases with severe destruction of the periodontal ligament extraction is indicated.

Teeth without severe secondary periodontal involvement can be treated with conventional or surgical endodontic therapy as necessary. The tooth is reexamined in 3-6 months for bony regeneration and the periodontal lesions can be treated with either closed or opened scaling techniques. A multi-rooted tooth with a Class I, II, or III lesion that has severe periodontal attachment loss affecting only one root can be partially salvaged with sectioning and conventional endodontic therapy of the retained portion of the tooth.

Extraction of Teeth with Periodontal Disease

The most common reason for extracting teeth with periodontal disease is Stage IV or severe periodontal disease. Teeth with less than 20-30% of remaining bone height have a poor prognosis. 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 Fistula Repair

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. Recurrent or large fistulas may require the use of a double-layer flap. A single-layer flap repair of oronasal or oroantral fistulas is initiated by the removal of the entire epithelial edge of the fistula using a #15 blade to remove a thin layer of mucosa around the perimeter of the fistula. 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 musosa with a simple interrupted pattern using 3-0 or 4-0 absorbable monofilament suture material such as Monocryl on a reverse cutting needle.

Recurrent or large fistulas may require the use of a double-layer flap. Several techniques for repair of oronasal fistulas have been described including a double reposition flap technique. The double reposition flap is initiated by excising the entire mucosal edge of the fistula except the palatal edge. A large semi-circular palatal mucoperiosteal flap is created palatal to the defect and elevated using a periosteal elevator. The palatal flap is rotated on its basilar attachment into the fistula and sutured in place with 3-0 or 4-0 absorbable suture material. The second layer of the flap is similar to the single-layer flap technique except that it is particularly important in the creation of the second layer of the flap to adequately incise the periosteal layer of the flap to ensure no tension is present on the flap following closure since this second layer of the flap is sutured to a more palatal location than a single-layer flap. The buccal mucoperiosteal flap is advanced palatally to cover the inverted flap and denuded palatine bone and is sutured in place using a simple interrupted pattern.

Home Care

Home care following periodontal therapy is an important part of 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.

The antimicrobial of choice for clinical use in dogs with periodontal disease based on susceptibility testing is amoxicillin-clavulanic acid, 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 patient requirements.

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 1 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 have been shown to decrease calculus formation in pets. The first specially formulated dental diet in dogs, Hill�s Prescription Diet, Canine T/D, is effective in the reduction of plaque, stain and calculus in dogs.⁹ Other diets and treats have also been shown to be effective in the reduction of plaque, stain and calculus in dogs.

References:

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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.  Harvey CE, Thornsberry, Miller BR, Shofer FS: Antimicrobial susceptibility of subgingival bacteria flora in dogs with gingivitis. Jour Vet Dent 12:4, 1995.

4.  DuPont GA: Prevention of periodontal disease. Vet Clin North Amer: Small Anim Pract 28:1129-1145, 1998.

5.  Wiggs RB, Lobprise HB: Periodontology. In: Wiggs RB, Lobprise HB, eds. Veterinary Dentistry Principles & Practice. Philadelphia: Lippincott-Raven, 1997:186-231.

6.  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.

7.  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.

8.  Manfra-Marretta S, Schloss AJ, Klippert LS. Classification and prognostic factors of endodontic-periodontic lesions in the dog. J Vet Dent 1992;9 (2):27-30.

9.  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.