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Nonsurgical periodontal therapy
Nonsurgical Periodontal Therapy W . P a u l C l e l a n d , Jr, D V M
The primary etiology of periodontal disease is bacterial infection. Bacteria exist as a biofilm (plaque) on the tooth and soft-tissue surfaces of the mouth. Biofilm is extremely resistant to antimicrobial activity. To effectively treat periodontal disease, the bacterial load must be reduced to allow healing of the inflamed tissues. Reduction of the bacterial load can be accomplished by surgical methods, nonsurgical methods, or a combination of the two. This article focuses on the nonsurgical treatment of periodontal disease. A thorough oral examination, which includes visual inspection and the use of a periodontal probe, is needed to determine the best therapy. Supragingival cleaning with power and hand scalers is the first step in the therapy process. The next step, subgingival scaling, is necessary to remove bacteria that are in direct contact with the periodontium. Effective subgingival plaque removal is time intensive and requires motivation, manual dexterity, and meticulous technique. Most veterinarians and veterinary technicians lack the training, instruments, and time to remove subgingival plaque effectively. To improve therapeutic results, adjunctive therapy in the form of oral systemic antibiotics or a locally applied doxycycline-containing polymer may be used. The success of periodontal therapy also is dependent on dental home care that takes place after professional treatment. The veterinarian and staff must be willing to educate and reinforce the dental home care efforts of the pet owner. Copyright © 2000 by W.B. Saunders Company
plaque. Plaque formation begins immediately after tooth eruption and immediately after a dental cleaning. The tooth surface is coated with salivary glycoproteins forming a pellicle to which bacteria can adhere. 2 As the bacteria colonize the tooth surface, they produce a matrix of exopolysaccharide glycocalyx polymers, which bind them frmly to the teeth. The bacterial colonies produce a complex community within the biofilm. Superficial bacteria have ready access to oxygen and nutrients and easily eliminate waste products. Bacteria deep within the biofilm have limited access to oxygen and nutrients and have more difficulty eliminating their waste products. The superficial bacteria are biologically active and are more susceptible to antimicrobials than are the deeper bacteria, which are dormant. ~ Dental plaque is composed of aerobic and anaerobic flora. The ratio of aerobic to anaerobic flora in gingivitis is the same both supragingivally and subgingivally, but the volume of supragingival flora is 100 times that of subgingival flora. With periodontitis, the percentage of gram-negative anaerobic flora increases, r,8,s5 Spirochetes that are found in periodontal pockets in dogs may have an effect on the homeostasis of periodontal disease, lo
Periodontium nflammation of the periodontal tissues, known as periodon. tal disease, is caused primarily by bacterial infection. The severity of disease is influenced by other factors that may include species, breed, genetics, age, chewing behavior, general health, occlusion, level of nutrition, food consistency, local irritants, s,2 presence of pathogenic bacteria, and the absence of beneficial bacteria. 3 To effectively treat periodontal disease, the bacterial load must be reduced to allow healing of the inflamed tissues. In addition, those factors contributing to the severity of disease must be corrected, if possible. Removal of the bacterial load can be accomplished by open, surgical methods; by closed, nonsurgical methods; or by a combination of the two. This article focuses on the closed, nonsurgical methods of periodontal disease therapy.
I
Dental Plaque Over 300 bacterial species have been recognized in the oral cavity of humans. 4 Dogs and cats have a similar variety of bacterial species. 5-13These bacteria colonize the surfaces of the teeth and soft tissues of the mouth as a biofilm, known as
From the Heska Corporation, Fort Collins, CO. Reprints not available. Copyright © 2000 by W.B. Saunders Company 1096-2867/00/1504-0005535.00/0 doi:10.1053/svms.2000.21043
The periodontium consists of the supporting structures of the tooth: the gingiva, the periodontal ligament, the cementum, and the alveolar bone. Firmly attached to the alveolar processes of the maxilla and the mandible, the gingiva surrounds the tooth and protects the underlying alveolar bone and supporting tissues from oral bacteria, fluids, and debris. A shallow gap, the gingival sulcus, exists between the gingiva and the tooth. 1.16
Therapy The goal of effective periodontal therapy is to remove dental plaque supragingivally and subgingivally. The plaque within the gingival sulcus incites the disease. The supragingival plaque provides the microbes that colonize the subgingival area. Thus, periodontal disease can be controlled effectively only with professional supragingival and subgingival cleaning combined with dental home care.
Oral Examination The first step in periodontal therapy is a thorough oral examination. Each tooth should be considered an individual patient. Carefully examine each tooth and its associated periodontium visually and with a periodontal probe. Look for plaque and calculus accumulation, gingival hyperplasia or recession, purulent discharge, and tooth mobility (Fig 1).
Clinical Techniques in Small Animal Practice, Vol 15, No 4 (November), 2000: pp 221-225
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pits and fissures on the crown of the tooth. Hand scalers can be used alone or as adjuncts to a power scaler, cleaning any remaining plaque and calculus from the crown of the tooth. A blast of air from an air/water syringe will improve visualization of remaining calculus. In addition, plaque-disclosing solution may be used to allow visualization of remaining plaque. Scaling leaves a rough tooth surface. The rough surface resuits in faster colonization of the tooth surfaces by plaque bacteria.17 Polishing after scaling will smooth the surface of the tooth, slowing the return of the plaque bacteria.
Snbgingival Cleaning--The Key to Successful Periodontal Therapy Fig 1. Calculus accumulation, gingival inflammation, and gingival recession can be seen in the oral examination of this patient with periodontal disease.
Periodontal Probing Gently place a periodontal probe into the gingival sulcus, parallel to the surface of the tooth and perpendicular to the gingival margin (Fig 2). Carefully trace completely around the tooth with the probe. Bleeding with gentle probing is an indication of inflammation. Healthy gingiva does not bleed with gentle probing. Measure the periodontal pocket depths and the attachment levels for each tooth. The periodontal pocket depth is the distance from the gingival margin to the bottom of the sulcus. The attachment level is the distance from the cementoenamel junction to the bottom of the sulcus. Measurements greater than 3 mm in the dog and measurements greater than 1 mm in the cat should be recorded on a dental chart. Those areas that have been recorded on the dental chart will require periodontal therapy. Any tooth with attachment loss greater than 75% of its root length should be extracted.
Supragingival Cleaning The crown of the tooth can be cleaned with a variety of instruments, including power and hand scalers. Power and hand scalers compliment each other. The power scalers allow rapid removal of plaque and calculus on the broad surfaces of the teeth, whereas hand scalers can be used in the hard-to-reach areas of the teeth. Power scalers can be sonic or ultrasonic. Sonic scalers are driven by compressed air. They vibrate at less than 20,000 cycles per second. For veterinary patients, they are not very efficient. Metal stacks, carbon rods, or quartz crystals vibrate between 25,000 and 42,000 cycles per second in ultasonic scalers. Ultrasonic scalers are highly efficient, but because of their rapid vibration, they can damage the tooth if used improperly. A light brushing touch should be used to allow the vibrations to remove the plaque and calculus. A water spray onto the tip of the scaler and the tooth should be constant to prevent overheating of the tooth. To prevent overheating, the ultrasonic scaler should not remain on an individual tooth longer than 15 seconds. If a tooth cannot be cleaned fully in less than 15 seconds, leave this tooth and clean other teeth. After approximately 30 seconds, return to the tooth that requires additional cleaning time. The hand dental sealer has a pointed tip allowing access to 222
Curettes and power scalers are used for subgingival mechanical cleaning. Curettes are hand instruments used in the subgingival area. Curettes have a rounded toe and back to prevent trauma to the overlying gingiva. The curette is drawn across the surface of the root to remove plaque, calculus, and the superficial layer of the cementum. This process is known as root scaling or root debridement. When the curette is placed subgingivally, it is difficult to see the cutting edge to ensure that it is at the proper angle. The curette is designed such that when the shank adjacent to the cutting edge is parallel to the surface one wants to clean, the cutting edge is positioned correctly for effective use (Fig 3). The cutting edge of the curette must be sharp and at the proper angle to remove the calculus and the diseased cementum. A dull curette will smooth the top surface of the calculus and not remove it. The sharpness of the curette can be determined by its ability to remove calculus or by its ability to remove a thin layer from the surface of an acrylic test stick. For some patients with heavy accumulation of calculus on the tooth roots, a curette may need to be sharpened several times during the scaling procedure. For other patients, the curette may remain sharp for the entire procedure. The ideal way to learn how to sharpen a curette is to spend time with a dental hygienist, who has the training and experience to give one excellent hands-on instruction. Special subgingival tips should be used on sonic or ultrasonic scalers during subgingival cleaning. As is done on the crown,
Fig 2. The periodontal probe is placed gently into the gingival sulcus parallel to the surface of the tooth and perpendicular to the gingival margin. Carefully trace completely around each tooth with the probe. w. PAUL CLELAND
Fig 3. The curette is placed subgingivally. The cutting edge is in proper position when the shank closest to the cutting edge is parallel to the surface being cleaned,
the power scaler may be used first, followed by the curette to remove residual plaque and calculus from the root surface. The curette may be used to remove the inflamed superficial layer of the gingival tissue, ie, gingival curettage. Root scaling with gingival curettage has not been shown to improve healing over root scaling alone. Root planing, the removal of all exposed cementum and the top layer of dentin, is unnecessary and may be detrimental to the reattachment of the periodontium to the tooth. Any calculus left on the root surface is coated with bacteria that will contribute to the progression of the periodontal disease. The diseased sulcus, ie, the periodontal pocket, is the ideal environment for the proliferation of disease-causing bacteria. It is warm, dark, moist, and contains nutritional support. 18 Any bacteria left in the pocket will replicate rapidly and recolonize the area. Effective subgingival plaque removal is time intensive and requires motivation, manual dexterity, and meticulous technique. In studies of root scaling without periodontal surgery by experienced human dentists, subgingival calculus was found on 17% to 69% of the root surfaces. Residual calculus was left on 85% of the root surfaces by less experienced human dentists. 19 Unlike human dentists and dental hygienists, who spend many weeks learning how to perform subgingival plaque removal, veterinarians and veterinary technicians receive minimal training in this technique.
Adjunctive Therapy Many factors contribute to inadequate subgingival plaque and calculus removal in veterinary clinics, including lack of training, lack of proper instruments, dental root morphology, and lack of time. Chemical adjuncts are gaining favor in human dentistry for plaque control and could be useful in veterinary dentistry. Among the nonantibiotic antimicrobials, chlorhexidine, a cationic bisbiguanide, is the most effective antimicrobial for supragingival plaque control. Chlorhexidine adsorbs to the tissues of the mouth and is released gradually over 24 hours in therapeutic concentrations. It kills bacteria within the plaque biofilm, as well as the bacteria that initially adhere to the dental pellicle. Dilute chlorhexidine solution frequently is used to irrigate subgingivally after a dental cleaning in veterinary medicine in an attempt to decrease residual subgingival bacteria. NONSURGICAL PERIODONTAL THERAPY
However, human studies with subgingival irrigation with chlorhexidine do not support this practice. In one study, a single subgingival irrigation with 0.12% chlorhexidine was performed and the tooth was extracted immediately. The tooth root had no residual antimicrobial activity. 2° In another human study, periodontal pockets were irrigated with 2.0% chlorhexidine every 2 weeks for 22 weeks. Plaque scores, probing depths, attachment levels, bleeding scores, and spirochete counts did not differ from saline-irrigated and nonirrigated controls, al Blood and gingival crevicular fluid dilute the chlorhexidine and flush it from the periodontal pocket, contributing to the decreased effectiveness of chlorhexidine used subgingivally. To achieve the desired results, higher concentrations and longer contact times may be needed, i° Antibiotic antimicrobials, delivered systemically or applied locally, are used in veterinary medicine as adjuncts to mechanical therapy. The 2 systemically delivered antibiotics approved by the US Food and Drug Administration (FDA) for veterinary dental use are amoxicillin-clavulanic acid and clindamycin. Amoxicillin-clavulanic acid (Clavamox, Pfizer Animal Health, Extom PA) has been approved by the FDA for the treatment of periodontal infections in dogs. Clindamycin (Antirobe, Pharmacia 6z Upj ohn, Kalamazoo, MI) is approved for the treatment of dental infections in dogs and cats. To be effective, systemic antibiotics must achieve and maintain therapeutic levels within the periodontal pocket. Although systemic antibiotics are useful in decreasing the severity of periodontal disease, the risk of development of resistant organisms in the mouth, in the intestinal tract, and in other body locations should preclude their use in all but high-risk patients. High-risk patients would include those with advanced periodontitis, immunosuppression because of metabolic disease, primary immunopathies, primary cardiac disease, and animals receiving dental scaling at the same time as surgical procedures) Local subgingival antimicrobial therapy does not subject the entire body to unnecessary exposure to the antimicrobial agent. Higher antimicrobial levels can be achieved at the site of the infection than can be obtained with systemic antibiotics. = The locally applied antimicrobial must remain at the site of the infection for a sufficient duration and must not be inactivated by local factors to achieve effective antibacterial activity. Emptying the contents of an antibiotic capsule, such as tetracycline, into the periodontal pocket will not achieve appropriate activity. In a human study, patients received biweekly subgingival irrigation with tetracycline solution (50 mg/mk). Plaque scores, probing depths, attachment levels, bleeding scores, and spirochete counts did not differ from saline-irrigated and nonirrigated controls. 2~ To achieve longer local contact times, a biodegradable delivery system containing doxycycline was developed. The Doxirobe gel (Pharmacia & Upjohn, Kalamazoo, MI; formally known as Heska Periceutic gel, Heska Corporation, Fort Collins, CO) is the only locally applied antimicrobial periodontal treatment approved by the FDA for use in veterinary dentistry. It contains 8.5% doxycycline hyclate in a biodegradable polymer and is indicated for the treatment and control of periodontal disease in dogs. The Doxirobe gel is applied to the affected periodontal pocket via a blunt cannula after subgingival scaling (Fig 4). The polymer hardens with exposure to moisture and remains in place for up to several weeks, releasing therapeutic levels of doxycycline. With exposure to the periodontal envi223
Marketing Nonsurgical Periodontal Therapy
Fig 4. The Doxirobe gel is applied to the periodontal pocket via a blunt cannula.
ronment, the polymer gradually biodegrades to carbon dioxide and water.
Continuing Care Nonsurgical periodontal therapy does not end when the patient recovers from the anesthesia used for professional treatment. Successful treatment depends on dental home care by the client after professional treatment. Unless supragingival plaque is controlled daily, it can mature and extend subgingivally. Numerous products are available for veterinary dental home care from veterinarians and pet shops. Obtaining owner compliance in a home care plan can be difficult. Do not expect pet owners to remember the home care directions if the instructions are given only at the time their pets are discharged after the professional treatment. The owners are distracted by thoughts such as "How much is this going to cost, will my pets be groggy, and will my pets be sick when they get home?" Give the instructions at the time of discharge and recommend a recheck of the pets' mouths in 2 weeks. The motive of these recheck visits is to have the owners return for reinforcement of the home care instructions. At the recheck visits, look at the areas that were treated and comment on how good they look. Ask the owners if they have been doing home care. In most cases, they will respond "No." Remind them that if they do not do home care, the benefits of the professional treatment will not last. Have a technician bring a toothbrush with toothpaste on it into the examination room, and let the owners brush their pet's teeth. By letting the owners attempt the tooth brushing, their problems with the brushing can be determined and corrected. Reinforce good things, and help them correct the things they are doing wrong. By the end of the visit they should be more comfortable brushing their pet's teeth. Unless tooth brushing becomes a habit, the owners will not continue it, no matter how comfortable they are with the technique. Suggest that they brush their pet's teeth in the same room, at the same time every day. Follow the brushing with a meal. In a short period of time their pets will realize that to eat, they must allow their teeth to be brushed. Training the pets will train the owners. 224
Most owners would prefer not to have their pets' teeth extracted. However, many owners will be reluctant to have periodontal therapy performed because of the cost of the professional treatment and the time committment after the professional treatment. It is the veterinary professional's job to convince the owners that the periodontal therapy is in the best interest of their pets. Regular periodontal therapy will not only prolong the life of the pet's teeth, but may also improve the quality of the pet's lives. Dogs and cats with periodontal disease develop a transient bacteremia when they chew and when they have their teeth cleaned or extracted. 1<2BThis bacteremia may contribute to systemic disease in dogs and cats. Debowes et a124 found an association between periodontal disease and histopathologic changes in the kidney, papillary muscle of the heart, and the liver parenchyma. Although many dogs and cats have been able to eat and survive without their teeth, the long-term effects of not being able to chew their food have not been studied. Extraction of mandibular teeth, especially the incisors and canines, leads to mandibular atrophy. With the atrophy, the tongue hangs from the mouth and becomes dry. Eating becomes more difficult. Extraction of the maxillary fourth premolar (a tooth commonly affected by periodontal disease) will result in the loss of the normal cleansing activity that occurs on the mandibular first molar during chewing. Without the natural cleansing, the mandibular first molar may become affected with periodontal disease. The mandibular bone loss that occurs when the mandibular first molar becomes affected by periodontal disease can lead to pathological fractures. Once the veterinary professionals are convinced that periodontal therapy is important for their patients, they must convince the pet owners. They cannot just tell the pet owners that their pets need periodontal therapy. They must show them. Lift the lips and show them the teeth. Take pictures with a polaroid or digital camera and give the pictures to the owners. Let them take the pictures home with them. Explain how their pet's periodontal disease may affect them systemically. Have them picture their pets growing old and healthy. Suggest what might happen if they do not have the treatment performed. Veterinary professionals must make the pet owners' portion of the treatment as simple as possible. To be effective, systemic antibiotics must be administered at the correct interval for the correct duration. Rarely will owners give all of the antibiotics prescribed. By using the Doxirobe gel, the owners do not have to give oral systemic antibiotics when their dogs get home. Finally, veterinary professionals must be sincere and enthusiastic when they present their treatment plans to the pet owners. Although not every pet owner will accept their recommendations, many will, if the veterinary professionals believe in their recommendations and present them with sincerity and enthusiasm. Happy smiles in pet owners come from healthy smiles in their pets.
References 1. Harvey CE, Emily PP: Periodontal disease, in Harvey CE, Emily PP (eds): Small Animal Dentistry. St Louis, Me, Mosby, pp 89-144, 1993 2. Wiggs RB, Lobprise HB: Periodontology, in Wiggs RB, Lobprise HB (eds): Veterinary Dentistry Principles and Practice. Philadelphia, PA, Lippincott-Raven, pp 186-231, 1997 3. Bollen CML, Vandekerckhove BNA, Papaioannou W, et al: Fullw. PAUL CLELAND
4, 5.
6.
7.
8. 9. 10. 11.
12.
13.
versus partial-mouth disinfection in the treatment of periodontal infections. A pilot study: Long-term microbiological observations. J Clin Periodontol 13:960-970, 1996 Darveau RP, Tanner A, Page RC: The microbial challenge in periodontitis. Periodontol 2000 14:12-32, 1997 Syed SA, Svanberg M, Svanberg G: The predominant cultivable dental plaque flora of beagle dogs with gingivitis. J Periodont Res 15:123-136, 1980 Syed SA, Svanberg M, Svanberg G: The predominant cultivable dental plaque flora of beagle dogs with periodontitis. J Clin Periodontol 8:45-56, 1981 Svanberg GK, Syed SA, Scott BW Jr: Differences between gingivitis and periodontitis associated microbial flora in the beagle dog. Relationship of plaque parameters to histological parameters of periodontal disease. J Periodont Res 17:1-11, 1982 Hennet PR, Harvey CE: Aerobes in periodontal disease in the dog: a review. J Vet Dent 8(1):9-11, 1991 Hennet PR, Harvey CE: Anaerobes in periodontal disease in the dog: A review. J Vet Dent 8(2):18-21, 1991 Hennet PR, Harvey CE: Spirochetes in periodontal disease in the dog: A review. J Vet Dent 8(3):16-17, 1991 Harvey CE, Thornsberry C, Miller BR: Subgingival bacteria--Comparison of culture results in dogs and cats with gingivitis. J Vet Dent 12:147-150, 1995 Nieves MA, Hartwig P, Kinyon JM, et al: Bacterial isolates from plaque and blood during and after routine dental procedures in dogs. Vet Surg 26:26-32, 1997 Longhofer SL, White JV, Godowski KC, et al: Antimicrobial sensitivity of microorganisms cultured from canine subgingival plaque. Proceedings of the 11th Annual Veterinary Dental Forum and Veterinary Dentistry 1997. Denver, Colorado, 1997, pp 150-152
NONSURGICAL PERIODONTAL THERAPY
14. Anwar H, Strap JL, Costerton JW: Establishment of aging biofilms: Possible mechanism of bacterial resistance to antimicrobial therapy. Antimicrob Agents Chemother 36(7):1347-1351, 1992 15. Davies RM: Rinses to control plaque and gingivitis. Int Dent J 42:276-280, 1992 (suppl 1) 16. Tholen MA: Veterinary periodontal therapy-l. Vet Med Small Anim Clinician 1045-1054, 1982 17. Quirynen M, Bollen CM: The influence of surface roughness and surface-free energy on supra- and subgingival plaque formation in man. A review of the literature. J Clin Periodontol 22:1-14, 1995 18. Addy M: Chlorhexidine compared with other locally delivered antimicrobials. A short review. J Clin Periodontol 13:957-964, 1986 19. Cobb CM: Non-surgical pocket therapy: mechanical. Ann Periodontol 1:443-490, 1996 20. Drisko CH: Non-surgical pocket therapy: Pharmacotherapeutics. Ann Periodontol 1:491-566, 1996 21. MacAIpine R, Magnusson I, Kiger R, et al: Antimicrobial irrigation of deep pockets to supplement oral hygiene instruction and root debridement. I. Bi-weekly irrigation. J Clin Periodontol 12:568577, 1985 22. Soskolne WA, Chajek T, Flashner M, et al: An in vivo study of the chlorhexidine release profile of the PerioChip in the gingival crevicular fluid, plasma and urine. J Clin Periodontol 25:1017-1021, 1998 23. Black AP, Cfichlow AM, Sanders JR: Bacteremia during ultrasonic teeth cleaning and extraction in the dog. J Am Anim Hosp Assoc 16:611-616, 1980 24. DeBowes LJ, Mosier D, Logan E, et al: Association of periodontal disease and histologic lesions in multiple organs from 45 dogs. J Vet Dent 13:57-60, 1996
225
The primary etiology of periodontal disease is bacterial infection. Bacteria exist as a biofilm (plaque) on the tooth and soft-tissue surfaces of the mouth. Biofilm is extremely resistant to antimicrobial activity. To effectively treat periodontal disease, the bacterial load must be reduced to allow healing of the inflamed tissues. Reduction of the bacterial load can be accomplished by surgical methods, nonsurgical methods, or a combination of the two. This article focuses on the nonsurgical treatment of periodontal disease. A thorough oral examination, which includes visual inspection and the use of a periodontal probe, is needed to determine the best therapy. Supragingival cleaning with power and hand scalers is the first step in the therapy process. The next step, subgingival scaling, is necessary to remove bacteria that are in direct contact with the periodontium. Effective subgingival plaque removal is time intensive and requires motivation, manual dexterity, and meticulous technique. Most veterinarians and veterinary technicians lack the training, instruments, and time to remove subgingival plaque effectively. To improve therapeutic results, adjunctive therapy in the form of oral systemic antibiotics or a locally applied doxycycline-containing polymer may be used. The success of periodontal therapy also is dependent on dental home care that takes place after professional treatment. The veterinarian and staff must be willing to educate and reinforce the dental home care efforts of the pet owner. Copyright © 2000 by W.B. Saunders Company
plaque. Plaque formation begins immediately after tooth eruption and immediately after a dental cleaning. The tooth surface is coated with salivary glycoproteins forming a pellicle to which bacteria can adhere. 2 As the bacteria colonize the tooth surface, they produce a matrix of exopolysaccharide glycocalyx polymers, which bind them frmly to the teeth. The bacterial colonies produce a complex community within the biofilm. Superficial bacteria have ready access to oxygen and nutrients and easily eliminate waste products. Bacteria deep within the biofilm have limited access to oxygen and nutrients and have more difficulty eliminating their waste products. The superficial bacteria are biologically active and are more susceptible to antimicrobials than are the deeper bacteria, which are dormant. ~ Dental plaque is composed of aerobic and anaerobic flora. The ratio of aerobic to anaerobic flora in gingivitis is the same both supragingivally and subgingivally, but the volume of supragingival flora is 100 times that of subgingival flora. With periodontitis, the percentage of gram-negative anaerobic flora increases, r,8,s5 Spirochetes that are found in periodontal pockets in dogs may have an effect on the homeostasis of periodontal disease, lo
Periodontium nflammation of the periodontal tissues, known as periodon. tal disease, is caused primarily by bacterial infection. The severity of disease is influenced by other factors that may include species, breed, genetics, age, chewing behavior, general health, occlusion, level of nutrition, food consistency, local irritants, s,2 presence of pathogenic bacteria, and the absence of beneficial bacteria. 3 To effectively treat periodontal disease, the bacterial load must be reduced to allow healing of the inflamed tissues. In addition, those factors contributing to the severity of disease must be corrected, if possible. Removal of the bacterial load can be accomplished by open, surgical methods; by closed, nonsurgical methods; or by a combination of the two. This article focuses on the closed, nonsurgical methods of periodontal disease therapy.
I
Dental Plaque Over 300 bacterial species have been recognized in the oral cavity of humans. 4 Dogs and cats have a similar variety of bacterial species. 5-13These bacteria colonize the surfaces of the teeth and soft tissues of the mouth as a biofilm, known as
From the Heska Corporation, Fort Collins, CO. Reprints not available. Copyright © 2000 by W.B. Saunders Company 1096-2867/00/1504-0005535.00/0 doi:10.1053/svms.2000.21043
The periodontium consists of the supporting structures of the tooth: the gingiva, the periodontal ligament, the cementum, and the alveolar bone. Firmly attached to the alveolar processes of the maxilla and the mandible, the gingiva surrounds the tooth and protects the underlying alveolar bone and supporting tissues from oral bacteria, fluids, and debris. A shallow gap, the gingival sulcus, exists between the gingiva and the tooth. 1.16
Therapy The goal of effective periodontal therapy is to remove dental plaque supragingivally and subgingivally. The plaque within the gingival sulcus incites the disease. The supragingival plaque provides the microbes that colonize the subgingival area. Thus, periodontal disease can be controlled effectively only with professional supragingival and subgingival cleaning combined with dental home care.
Oral Examination The first step in periodontal therapy is a thorough oral examination. Each tooth should be considered an individual patient. Carefully examine each tooth and its associated periodontium visually and with a periodontal probe. Look for plaque and calculus accumulation, gingival hyperplasia or recession, purulent discharge, and tooth mobility (Fig 1).
Clinical Techniques in Small Animal Practice, Vol 15, No 4 (November), 2000: pp 221-225
~21
pits and fissures on the crown of the tooth. Hand scalers can be used alone or as adjuncts to a power scaler, cleaning any remaining plaque and calculus from the crown of the tooth. A blast of air from an air/water syringe will improve visualization of remaining calculus. In addition, plaque-disclosing solution may be used to allow visualization of remaining plaque. Scaling leaves a rough tooth surface. The rough surface resuits in faster colonization of the tooth surfaces by plaque bacteria.17 Polishing after scaling will smooth the surface of the tooth, slowing the return of the plaque bacteria.
Snbgingival Cleaning--The Key to Successful Periodontal Therapy Fig 1. Calculus accumulation, gingival inflammation, and gingival recession can be seen in the oral examination of this patient with periodontal disease.
Periodontal Probing Gently place a periodontal probe into the gingival sulcus, parallel to the surface of the tooth and perpendicular to the gingival margin (Fig 2). Carefully trace completely around the tooth with the probe. Bleeding with gentle probing is an indication of inflammation. Healthy gingiva does not bleed with gentle probing. Measure the periodontal pocket depths and the attachment levels for each tooth. The periodontal pocket depth is the distance from the gingival margin to the bottom of the sulcus. The attachment level is the distance from the cementoenamel junction to the bottom of the sulcus. Measurements greater than 3 mm in the dog and measurements greater than 1 mm in the cat should be recorded on a dental chart. Those areas that have been recorded on the dental chart will require periodontal therapy. Any tooth with attachment loss greater than 75% of its root length should be extracted.
Supragingival Cleaning The crown of the tooth can be cleaned with a variety of instruments, including power and hand scalers. Power and hand scalers compliment each other. The power scalers allow rapid removal of plaque and calculus on the broad surfaces of the teeth, whereas hand scalers can be used in the hard-to-reach areas of the teeth. Power scalers can be sonic or ultrasonic. Sonic scalers are driven by compressed air. They vibrate at less than 20,000 cycles per second. For veterinary patients, they are not very efficient. Metal stacks, carbon rods, or quartz crystals vibrate between 25,000 and 42,000 cycles per second in ultasonic scalers. Ultrasonic scalers are highly efficient, but because of their rapid vibration, they can damage the tooth if used improperly. A light brushing touch should be used to allow the vibrations to remove the plaque and calculus. A water spray onto the tip of the scaler and the tooth should be constant to prevent overheating of the tooth. To prevent overheating, the ultrasonic scaler should not remain on an individual tooth longer than 15 seconds. If a tooth cannot be cleaned fully in less than 15 seconds, leave this tooth and clean other teeth. After approximately 30 seconds, return to the tooth that requires additional cleaning time. The hand dental sealer has a pointed tip allowing access to 222
Curettes and power scalers are used for subgingival mechanical cleaning. Curettes are hand instruments used in the subgingival area. Curettes have a rounded toe and back to prevent trauma to the overlying gingiva. The curette is drawn across the surface of the root to remove plaque, calculus, and the superficial layer of the cementum. This process is known as root scaling or root debridement. When the curette is placed subgingivally, it is difficult to see the cutting edge to ensure that it is at the proper angle. The curette is designed such that when the shank adjacent to the cutting edge is parallel to the surface one wants to clean, the cutting edge is positioned correctly for effective use (Fig 3). The cutting edge of the curette must be sharp and at the proper angle to remove the calculus and the diseased cementum. A dull curette will smooth the top surface of the calculus and not remove it. The sharpness of the curette can be determined by its ability to remove calculus or by its ability to remove a thin layer from the surface of an acrylic test stick. For some patients with heavy accumulation of calculus on the tooth roots, a curette may need to be sharpened several times during the scaling procedure. For other patients, the curette may remain sharp for the entire procedure. The ideal way to learn how to sharpen a curette is to spend time with a dental hygienist, who has the training and experience to give one excellent hands-on instruction. Special subgingival tips should be used on sonic or ultrasonic scalers during subgingival cleaning. As is done on the crown,
Fig 2. The periodontal probe is placed gently into the gingival sulcus parallel to the surface of the tooth and perpendicular to the gingival margin. Carefully trace completely around each tooth with the probe. w. PAUL CLELAND
Fig 3. The curette is placed subgingivally. The cutting edge is in proper position when the shank closest to the cutting edge is parallel to the surface being cleaned,
the power scaler may be used first, followed by the curette to remove residual plaque and calculus from the root surface. The curette may be used to remove the inflamed superficial layer of the gingival tissue, ie, gingival curettage. Root scaling with gingival curettage has not been shown to improve healing over root scaling alone. Root planing, the removal of all exposed cementum and the top layer of dentin, is unnecessary and may be detrimental to the reattachment of the periodontium to the tooth. Any calculus left on the root surface is coated with bacteria that will contribute to the progression of the periodontal disease. The diseased sulcus, ie, the periodontal pocket, is the ideal environment for the proliferation of disease-causing bacteria. It is warm, dark, moist, and contains nutritional support. 18 Any bacteria left in the pocket will replicate rapidly and recolonize the area. Effective subgingival plaque removal is time intensive and requires motivation, manual dexterity, and meticulous technique. In studies of root scaling without periodontal surgery by experienced human dentists, subgingival calculus was found on 17% to 69% of the root surfaces. Residual calculus was left on 85% of the root surfaces by less experienced human dentists. 19 Unlike human dentists and dental hygienists, who spend many weeks learning how to perform subgingival plaque removal, veterinarians and veterinary technicians receive minimal training in this technique.
Adjunctive Therapy Many factors contribute to inadequate subgingival plaque and calculus removal in veterinary clinics, including lack of training, lack of proper instruments, dental root morphology, and lack of time. Chemical adjuncts are gaining favor in human dentistry for plaque control and could be useful in veterinary dentistry. Among the nonantibiotic antimicrobials, chlorhexidine, a cationic bisbiguanide, is the most effective antimicrobial for supragingival plaque control. Chlorhexidine adsorbs to the tissues of the mouth and is released gradually over 24 hours in therapeutic concentrations. It kills bacteria within the plaque biofilm, as well as the bacteria that initially adhere to the dental pellicle. Dilute chlorhexidine solution frequently is used to irrigate subgingivally after a dental cleaning in veterinary medicine in an attempt to decrease residual subgingival bacteria. NONSURGICAL PERIODONTAL THERAPY
However, human studies with subgingival irrigation with chlorhexidine do not support this practice. In one study, a single subgingival irrigation with 0.12% chlorhexidine was performed and the tooth was extracted immediately. The tooth root had no residual antimicrobial activity. 2° In another human study, periodontal pockets were irrigated with 2.0% chlorhexidine every 2 weeks for 22 weeks. Plaque scores, probing depths, attachment levels, bleeding scores, and spirochete counts did not differ from saline-irrigated and nonirrigated controls, al Blood and gingival crevicular fluid dilute the chlorhexidine and flush it from the periodontal pocket, contributing to the decreased effectiveness of chlorhexidine used subgingivally. To achieve the desired results, higher concentrations and longer contact times may be needed, i° Antibiotic antimicrobials, delivered systemically or applied locally, are used in veterinary medicine as adjuncts to mechanical therapy. The 2 systemically delivered antibiotics approved by the US Food and Drug Administration (FDA) for veterinary dental use are amoxicillin-clavulanic acid and clindamycin. Amoxicillin-clavulanic acid (Clavamox, Pfizer Animal Health, Extom PA) has been approved by the FDA for the treatment of periodontal infections in dogs. Clindamycin (Antirobe, Pharmacia 6z Upj ohn, Kalamazoo, MI) is approved for the treatment of dental infections in dogs and cats. To be effective, systemic antibiotics must achieve and maintain therapeutic levels within the periodontal pocket. Although systemic antibiotics are useful in decreasing the severity of periodontal disease, the risk of development of resistant organisms in the mouth, in the intestinal tract, and in other body locations should preclude their use in all but high-risk patients. High-risk patients would include those with advanced periodontitis, immunosuppression because of metabolic disease, primary immunopathies, primary cardiac disease, and animals receiving dental scaling at the same time as surgical procedures) Local subgingival antimicrobial therapy does not subject the entire body to unnecessary exposure to the antimicrobial agent. Higher antimicrobial levels can be achieved at the site of the infection than can be obtained with systemic antibiotics. = The locally applied antimicrobial must remain at the site of the infection for a sufficient duration and must not be inactivated by local factors to achieve effective antibacterial activity. Emptying the contents of an antibiotic capsule, such as tetracycline, into the periodontal pocket will not achieve appropriate activity. In a human study, patients received biweekly subgingival irrigation with tetracycline solution (50 mg/mk). Plaque scores, probing depths, attachment levels, bleeding scores, and spirochete counts did not differ from saline-irrigated and nonirrigated controls. 2~ To achieve longer local contact times, a biodegradable delivery system containing doxycycline was developed. The Doxirobe gel (Pharmacia & Upjohn, Kalamazoo, MI; formally known as Heska Periceutic gel, Heska Corporation, Fort Collins, CO) is the only locally applied antimicrobial periodontal treatment approved by the FDA for use in veterinary dentistry. It contains 8.5% doxycycline hyclate in a biodegradable polymer and is indicated for the treatment and control of periodontal disease in dogs. The Doxirobe gel is applied to the affected periodontal pocket via a blunt cannula after subgingival scaling (Fig 4). The polymer hardens with exposure to moisture and remains in place for up to several weeks, releasing therapeutic levels of doxycycline. With exposure to the periodontal envi223
Marketing Nonsurgical Periodontal Therapy
Fig 4. The Doxirobe gel is applied to the periodontal pocket via a blunt cannula.
ronment, the polymer gradually biodegrades to carbon dioxide and water.
Continuing Care Nonsurgical periodontal therapy does not end when the patient recovers from the anesthesia used for professional treatment. Successful treatment depends on dental home care by the client after professional treatment. Unless supragingival plaque is controlled daily, it can mature and extend subgingivally. Numerous products are available for veterinary dental home care from veterinarians and pet shops. Obtaining owner compliance in a home care plan can be difficult. Do not expect pet owners to remember the home care directions if the instructions are given only at the time their pets are discharged after the professional treatment. The owners are distracted by thoughts such as "How much is this going to cost, will my pets be groggy, and will my pets be sick when they get home?" Give the instructions at the time of discharge and recommend a recheck of the pets' mouths in 2 weeks. The motive of these recheck visits is to have the owners return for reinforcement of the home care instructions. At the recheck visits, look at the areas that were treated and comment on how good they look. Ask the owners if they have been doing home care. In most cases, they will respond "No." Remind them that if they do not do home care, the benefits of the professional treatment will not last. Have a technician bring a toothbrush with toothpaste on it into the examination room, and let the owners brush their pet's teeth. By letting the owners attempt the tooth brushing, their problems with the brushing can be determined and corrected. Reinforce good things, and help them correct the things they are doing wrong. By the end of the visit they should be more comfortable brushing their pet's teeth. Unless tooth brushing becomes a habit, the owners will not continue it, no matter how comfortable they are with the technique. Suggest that they brush their pet's teeth in the same room, at the same time every day. Follow the brushing with a meal. In a short period of time their pets will realize that to eat, they must allow their teeth to be brushed. Training the pets will train the owners. 224
Most owners would prefer not to have their pets' teeth extracted. However, many owners will be reluctant to have periodontal therapy performed because of the cost of the professional treatment and the time committment after the professional treatment. It is the veterinary professional's job to convince the owners that the periodontal therapy is in the best interest of their pets. Regular periodontal therapy will not only prolong the life of the pet's teeth, but may also improve the quality of the pet's lives. Dogs and cats with periodontal disease develop a transient bacteremia when they chew and when they have their teeth cleaned or extracted. 1<2BThis bacteremia may contribute to systemic disease in dogs and cats. Debowes et a124 found an association between periodontal disease and histopathologic changes in the kidney, papillary muscle of the heart, and the liver parenchyma. Although many dogs and cats have been able to eat and survive without their teeth, the long-term effects of not being able to chew their food have not been studied. Extraction of mandibular teeth, especially the incisors and canines, leads to mandibular atrophy. With the atrophy, the tongue hangs from the mouth and becomes dry. Eating becomes more difficult. Extraction of the maxillary fourth premolar (a tooth commonly affected by periodontal disease) will result in the loss of the normal cleansing activity that occurs on the mandibular first molar during chewing. Without the natural cleansing, the mandibular first molar may become affected with periodontal disease. The mandibular bone loss that occurs when the mandibular first molar becomes affected by periodontal disease can lead to pathological fractures. Once the veterinary professionals are convinced that periodontal therapy is important for their patients, they must convince the pet owners. They cannot just tell the pet owners that their pets need periodontal therapy. They must show them. Lift the lips and show them the teeth. Take pictures with a polaroid or digital camera and give the pictures to the owners. Let them take the pictures home with them. Explain how their pet's periodontal disease may affect them systemically. Have them picture their pets growing old and healthy. Suggest what might happen if they do not have the treatment performed. Veterinary professionals must make the pet owners' portion of the treatment as simple as possible. To be effective, systemic antibiotics must be administered at the correct interval for the correct duration. Rarely will owners give all of the antibiotics prescribed. By using the Doxirobe gel, the owners do not have to give oral systemic antibiotics when their dogs get home. Finally, veterinary professionals must be sincere and enthusiastic when they present their treatment plans to the pet owners. Although not every pet owner will accept their recommendations, many will, if the veterinary professionals believe in their recommendations and present them with sincerity and enthusiasm. Happy smiles in pet owners come from healthy smiles in their pets.
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