Hartz Companion Animal - Feline Odontoclastic Resorption Lesions


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Odontoclasts are multinucleated
cells that destroy part or all of the
affected tooth’s hard tissue.
Odontoclastic resorption starts in the
cementum (i.e., a bone-like tissue that
covers the tooth root) and spreads into
the dentin via dentinal tubules. The
destroyed root surface is replaced by
cementum. Enamel becomes involved
secondary to the “caving in” of
underlying dentin, creating a resorption
lesion. Feline odontoclastic resorption
is a common syndrome affecting cat
teeth. Feline odontoclastic resorption
lesions (FORLs) have been referred to
as cavities, neck lesions, cervical line or
neck erosions, oral or odontoclastic
resorption lesions (ORLs), and external
odontoclastic resorption lesions

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Hartz Companion Animal - Feline Odontoclastic Resorption Lesions

  1. 1. A NEWSLETTER OF PRACTICAL MEDICINE FOR VETERINARY PROFESSIONALS NOVEMBER 2006 VOLUME 4, NUMBER 4 Feline Odontoclastic Resorption Lesions Jan Bellows, DVM, DAVDC, DABVP Hometown Animal Hospital and All Pets Dental Clinic Weston, FloridaWHAT ARE ODONTOCLASTIC leads to reparative formation of bone or s Stage 1—Lesions extend only intoRESORPTION LESIONS? cementum-like tissue. The initial the cementum covering the root. This Odontoclasts are multinucleated cementum resorption extends into the stage occurs subgingivally where thecells that destroy part or all of the dentin, forming resorption channels that tooth surface is exposed to cells thataffected tooth’s hard tissue. often extend into the dentin of the can become odontoclasts. BecauseOdontoclastic resorption starts in the crown. The loss of crown dentin increases there is no enamel involvement, Stagecementum (i.e., a bone-like tissue that the fragility of the tooth and the 1 lesions are difficult to detect; theycovers the tooth root) and spreads into unsupported enamel. Alternatively, the are not radiographically apparent.the dentin via dentinal tubules. The enamel is also resorbed. Either s Stage 2—Lesions progress throughdestroyed root surface is replaced by mechanism results in the classic clinical the cementum into the dentin of thecementum. Enamel becomes involved presentation, a cavity filled with root or crown but do not expose thesecondary to the “caving in” of connective tissue. pulp. Stage 2 lesions are painfulunderlying dentin, creating a resorption because dentin tubules are exposed.lesion. Feline odontoclastic resorption CLASSIFICATION OF Hyperplastic gingiva may cover theseis a common syndrome affecting cat ODONTOCLASTIC defects. Enamel may be affected fromteeth. Feline odontoclastic resorption RESORPTION LESIONSlesions (FORLs) have been referred to There are several systems in use toas cavities, neck lesions, cervical line or classify resorption lesions. One method isneck erosions, oral or odontoclastic to characterize the lesions into three ALSO IN THIS ISSUE:resorption lesions (ORLs), and external stages: acute, chronic, and remodeling. Another system is based on clinical Ask the Vet ................................ 5odontoclastic resorption lesions(EORLs). and radiographic examination of the Intraoral Imaging Techniques..... 6 Surface resorption of root cementum FORL:
  2. 2. A NEWSLETTER OF PRACTICAL MEDICINE FOR VETERINARY PROFESSIONALS NOVEMBER 2006 VOLUME 4, NUMBER 4 Consulting Editors Bruce Truman Senior Director Animal Health and Nutrition The Hartz Mountain Corporation Jill A. Richardson, DVM Director Consumer Relations The Hartz Mountain Corporation Associate Editor David Levy Assistant Manager Animal Health and Nutrition The Hartz Mountain Corporation HARTZ® COMPANION ANIMAL SM A B is produced for The Hartz Mountain Figure 1. (A) Stage 2 FORL. (B) Radiograph of Stage 2 FORL. Corporation by Veterinary Learning Systems, 780 Township Line Rd., Yardley, PA 19067. odontoclasts of the periodontium or s Type 2—The affected tooth is Copyright © 2006 The Hartz Mountain subjacent dentin (Figure 1). ankylosed to the alveolus. Type 2 Corporation. All rights reserved. s Stage 3—Lesions progress into the lesions are not associated with Hartz® and other marks are owned by pulp of the root canal or pulp periodontitis; instead, noninflammatory The Hartz Mountain Corporation. chamber and are painful. Bleeding on replacement resorption results in probing and spontaneous fracture of ankylosis (surface and/or replacement Printed in U.S.A. No part of this the crown (enamel and dentin) can be resorption in which the bone and publication may be reproduced in any seen (Figure 2). tooth substance become fused). form without the express written Type 2 lesions most commonly permission of the publisher. s Stage 4—Lesions destroy a significant affect the mandibular third premolars amount of the crown (Figure 3). For more information on The Hartz (Figure 5). s Stage 5—Lesions have significant Mountain Corporation, visit root replacement resorption with www.hartz.com. WHAT CAUSES FELINE healing of the gingiva. There will not ODONTOCLASTIC be any clinically apparent tooth tissue. RESORPTION LESIONS? The cause of odontoclastic resorption A recent investigation of factors Some also classify FORLs based on is not known. Histologically, there is no controlling calcium homeostasis in cats the radiographic appearance of the decalcification in the dentin, suggesting with and without FORLs has shown that periodontal ligament space: that the resorption lesions are not similar serum hydroxy vitamin D concentration s Type 1—Lesions are caused by to human dental caries most often caused is elevated in cats with FORLs and that inflammation (periodontitis, by Streptococcus mutans. Theories include cats with FORLs may have been fed diets endodontic disease). The root appears increased calcium in feline diets and with excessive vitamin D content. A normal, and periodontal ligament abnormal pressure on the affected factor that creates abnormal formation or space is still observable. The teeth as well as feline leukemia and mineralization of cementum could mandibular molar is most commonly immunodeficiency disease. The etiology precipitate the development of cemental affected (Figure 4). is unknown but is likely multifactorial. resorptions. Experimental studies of the2 HARTZ COMPANION ANIMAL ® SM • NOVEMBER 2006 • VOL. 4, NO. 4
  3. 3. dental effects of vitamin D toxicosis inother species show effects similar to thoseseen in cats with FORLs.HOW ARE FELINEODONTOCLASTICRESORPTION LESIONSDIAGNOSED? Most affected cats do not showclinical signs. Some cats may experience Figure 2. Stage 3 FORL. Figure 3. Stage 4 FORL.hypersalivation, oral bleeding, or difficultychewing. Affected cats may pick up anddrop food (especially hard food) wheneating; others hiss while chewing. Behavior changes, such as becomingreclusive or aggressive, have been noted insome cats with FORLs. A cotton-tipped applicator applied tothe suspected FORL (Stages 2 through4) usually causes pain evidenced by jaw Aspasms. FORLs can occur above or below Figure 5. Type 2 FORL.the free gingival margin. Most occurat the labial or buccal surface near thecementoenamel junction where the free s Maxillary premolars and molars (twogingiva meets the tooth surface; calculus films—one for each side)and hyperplastic gingival tissue may s Mandibular incisors (one film)obscure the lesion. s Mandibular canines (two films—one FORLs can be found on any tooth; for each side)the mandibular third premolar and molar s Mandibular premolars and molarsare most commonly affected, followed bythe maxillary third and fourth premolars. (two films—one for each side) With the cat under general anesthesia, Blesions can be examined with an explorer; ARE ALL CATS EQUALLYa fine Shepherd’s hook type is preferred. Figure 4. (A) Type 1 FORL of the AFFECTED?The explorer helps identify subgingival mandibular molar. (B) Radiograph of Reported studies reveal that 20% tolesions coronal to the alveolar bone; the Type 1 lesion with visible periodontal 72% of cats are affected with FORLs. ligament space.furcation area is a frequent site, and the The reported variance is related toexaminer must distinguish a resorption diagnostic methods: Some studies entaillesion from disease limited to alveolar visual confirmation only compared withbone loss. for cats presented for an oral assessment, others that include visual, tactile, and The lesions can be detected through a treatment, and prevention visit. radiologic examination. Most of thesecombination of visual inspection, tactile Radiographic appearance varies from studies have shown an increasedexamination with a dental explorer, and minute radiolucent defects of the tooth incidence with increasing age.radiography. primarily at the cementoenamel junction The mandibular third premolars are Radiography will identify lesions to internal resorption and ankylosis of the the most commonly affected teeththat are localized to the root surfaces apex to the supporting bone. (Figure 6). Often, both sides are affected.within the alveolar bone, which may Intraoral films should include:not be detected by clinical methods. TREATMENT s Maxillary incisors (one film)Consequently, radiography is required to The first step in treatment of andiagnose FORLs. Complete survey s Maxillary canines (two films—one for odontoclastic resorption–affected toothintraoral radiographs are recommended each side) is proper diagnosis. Under general HARTZ® COMPANION ANIMALSM • NOVEMBER 2006 • VOL. 4, NO. 4 3
  4. 4. compared with other ankylosed root(s) to continue fusing with multirooted teeth. the alveolar bone. After clinical and tactile examination, PREVENTION intraoral radiographs To date, there is no known proven are taken to evaluate method to prevent FORLs. Once a root structure and definitive etiology is determined, involvement of the methods of prevention will hopefully be pulp chamber. developed. FORLs areFigure 6. Multiple FORLs on the mandibular third premolar. considered to be SUGGESTED READING progressive and can be painful to the patient. Lyon KF: Odontoclastic resorptive lesions, in August JR (ed): Consultations in Feline Internal Medicine, ed 5.anesthesia, suspected lesions should be For Type 1 lesions in which the St. Louis, Elsevier Science, 2006.examined with a fine Shepherd’s hook periodontal ligament is observable on Lyon KF: Subgingival odontoclastic resorptive lesions.type of explorer. The furcation area radiographs, the recommended treatment Classification, treatment, and results in 58 cats. Vet(where tooth roots meet) is a frequent Clin North Am Small Anim Pract 22(6):1417–1432, is flap exposure followed by full crown 1992.site of lesions, and the examiner must and root extraction. Type 2 lesions in Reiter AM, Lewis JR, Okuda A: Update on the etiologydistinguish between a resorption lesion various stages of ankylosis are treated of tooth resorption in domestic cats. Vet Clin Northand disease limited to alveolar bone loss either by conservative management until Am Small Anim Pract 35(4):913–942, 2005.secondary to periodontal disease. This is the lesion penetrates into the oral cavity Reiter AM, Mendoza KA: Feline odontoclastic resorptive lesions—An unsolved enigma in veterinaryespecially true for the mandibular molar, or, preferably, by crown amputation via dentistry. Vet Clin North Am Small Anim Practwhere the furcation is distally located flap exposure and flap closure, leaving 32(4):791–837, 2002.
  5. 5. Jill A. Richardson, DVM, is Director of Consumer Relations at The Hartz Mountain Corporation. ASK TH E VETQI have two dogs that I have been giving rawhidefor many years. I recently spoke with anotherveterinarian who informed me that rawhide is efficacy of rawhide published in the Journal of the American Veterinary Medical Association, dogs were fed three rawhide strips per day for 3 weeks, and no adverse effects from chewing and/or consuming rawhide were noted.1 Also, undigested piecesvery dangerous and is made with arsenic and of rawhide were not found in the feces of any of the studyformaldehyde. Now I am worried! Can you please dogs.help clear this up? What are the nutritional values for rawhide?ARawhide was first introduced as a pet treat in the 1950s asa way of satisfying a dog’s natural need to chew. Rawhidecan provide the chewing satisfaction that dogs crave and,when used daily, can also effectively remove plaque and Rawhide is approximately 80% to 85% protein, 10% to 12% fiber and moisture, and 1% to 2% fat. Rawhide is not considered a food item, but for those counting calories, rawhide has about 130 calories per ounce.tartar. You may find the following information about How does rawhide help keep teeth clean?rawhide useful. Dogs have a natural instinct for chewing. Giving a dog rawhide treats to chew helps keep their teeth and gums healthy. TheWhat is rawhide? abrasive action of rawhide chewing helps reduce plaque andRawhide is simply the inner layer of cattle hide. During calculus. Rawhide also provides the necessary chewing exerciseprocessing, cattle skin is split into an inner and an outer layer. to strengthen gums and is a great way to relieve boredom,The outer layer is tougher and is used in the leather industry for frustration, or anxiety.such items as shoes and clothing. The inner layer is softer and isformed into various shapes for dog rawhide chews. Since it is How effective is rawhide at cleaning a dog’s teeth?made from cattle hide, rawhide is not recommended for animals Rawhide has been shown to be an effective way of decreasingwith beef allergies. plaque and calculus formation. In fact, according to a study, rawhide effectively decreased plaque by 25% when given dailyHow is Hartz® rawhide manufactured? as a treat.1The inner layer of the hide comes in raw and is cleaned with Rawhide coated with HMP (hexametaphosphate) is evena food-grade prewash. It is later treated with food-grade more effective at reducing tartar formation on dogs’ teeth thanwhitening and antibacterial agents. Afterward, it is rinsed regular rawhide. HMP is classified as a food additive and worksthoroughly and rolled through a ringer. It is then formed into by interfering with the mineralization of plaque, therebyshapes and oven dried. To ensure the highest quality and preventing accumulation and tartar formation. It can also helpsanitation, samples of the product are tested before, during, and soften and remove existing tartar. According to a study byafter the process by members of the Hartz Quality Control Hartz, when dogs chewed rawhide coated with HMP, plaqueTeam. was decreased up to 83%.2 Arsenic, formaldehyde, or other dangerous chemicals are notused in processing Hartz rawhide. What is the difference between basted and infused rawhide?How safe is rawhide? Basted rawhide has flavor coating on the outside of the rawhide.The Hartz Mountain Corporation prides itself on providing the Infused rawhide has flavor infused throughout. Infused rawhide ishighest quality rawhide. As previously stated, testing of rawhide produced using a patented process in which chicken stock istakes place before, during, and after the production process. Quality infused throughout the entire hide to increase the flavor and enticecontrol continues through product monitoring and inspection. dogs to chew longer. According to a Hartz study, dogs prefer Rawhide is considered highly digestible. In a study on the infused rawhide 20 to 1 over unflavored rawhide. (continues on back cover) Additional newsletters may be obtained by contacting us at feedback@hartz.com or by phone at 800-275-1414. HARTZ® COMPANION ANIMALSM • NOVEMBER 2006 • VOL. 4, NO. 4 5
  6. 6. Intraoral Imaging Techniques* IMAGE FIELD AND FILM PLACEMENT PATIENT POSITIONING Figure 1. Projection for maxillary incisors. (A) The tubehead should be centered over the upper incisors. The arrow depicts the angle of the primary x- ray beam. Size 2 film is recommended for viewing Film all of the upper dentition to the level of the first premolar. Size 4 film can also fit in a cat’s mouth if preferred. (B) The cat’s head should be placed in ventral recumbency with a small roll inserted under the chin to A B keep the hard palate parallel to the table top. Size 2 or 4 intraoral film can then be placed below the incisors and canine teeth. The x-ray cone should be directed downward at an angle of 60˚ to the horizontal plane or the hard palate. The primary x-ray beam will be almost perpendicular to the bisecting plane. Figure 2. Lateral oblique projection for maxillary canine teeth. (A) The tubehead should be centered over the upper canine tooth and adjacent premolars. The arrow depicts Film the direction of the primary x-ray beam. Size 2 intraoral film is recommended for cats. (B) The cat’s head should be placed in ventral recumbency and a roll positioned under the jaw to keep the hard palate parallel to the table top. Size 2 A B intraoral film can then be placed under the canine tooth and premolars. The x-ray cone should be horizontally directed at an angle of 45˚ as shown and tipped downward at an angle of 45˚ to 60˚ to the horizontal plane of the hard palate. The primary x-ray beam will be almost perpendicular to the bisecting plane. Figure 3. Projection for maxillary premolars and molar. (A) The tubehead should be centered Film over the side of the cat’s face just below the lateral canthus. The mesial edge of the cone is near the medial canthus, and the distal edge of the cone is at the base of the ear. The arrow depicts the direction of the primary x-ray beam. Size 2 or 4 intraoral film can be used to A B view the entire upper lateral dentition. (B) The cat’s head should be placed in ventral recumbency and a small roll inserted under the neck to keep the hard palate parallel to the table top. Size 2 or 4 intraoral film can then be placed under the hard palate. The x-ray cone should be directed downward at an approximate angle of 30˚ to the horizontal plane of the table top or hard palate to minimize superimposition of the zygomatic arch. The primary x-ray beam should not be perpendicular to the bisecting plane. *From: Intraoral imaging techniques, in Mulligan TW, Aller SA, Williams CA: Atlas of Canine & Feline Radiography. Yardley, PA, Veterinary Learning Systems, 1998, pp 27–44. The book can be purchased online at www.vlsstore.com or by calling 800-426-9119.6 HARTZ COMPANION ANIMAL ® SM • NOVEMBER 2006 • VOL. 4, NO. 4
  7. 7. IMAGE FIELD AND FILM PLACEMENT PATIENT POSITIONINGFigure 4. Projectionfor mandibular incisorsand canine teeth. (A) Thetubehead should be centeredover the lower incisors. Thearrow depicts the directionof the primary x-ray beam.Size 2 intraoral film isrecommended forradiographs of the entire Filmlower dentition to the canineteeth; however, size 4 filmcan be used if preferred. (B)The cat’s head should bepositioned in dorsalrecumbency and a small roll A Binserted under the neck tokeep the hard palate parallel to the table top. Intraoral film can then be placed below the incisors and canine teeth. The x-ray cone should be directed at anapproximate angle of 60˚ to the horizontal plane of the hard palate or table top. The primary x-ray beam will be almost perpendicular to the bisecting angle.Figure 5. Lateraloblique projection formandibular canine teeth.(A) The tubehead should becentered over the mandibularcanine tooth. The arrowdepicts the direction of the x-ray beam. Unlike obliqueprojection in dogs, thepremolars and canine teethdo not usually become Filmsuperimposed for radiographsof cats. The view shows theinterdental (interproximal)bone of the canine tooth andthird premolar. Size 2 A Bintraoral film isrecommended. (B) The cat’s head should be placed in dorsal recumbency and a roll positioned under the neck to keep the hard palate parallel to the table top.Size 2 intraoral film can then be placed under the canine tooth and third premolar. The x-ray cone should be directed toward the interproximal space of thelateral incisor and canine tooth as shown and tipped downward at an angle of 45˚ to 60˚ to the hard palate. The primary x-ray beam will be almost perpendicularto the bisecting plane. Gauze sponges can be used to stabilize the film in the back of the mouth. All sponges and the film should be removed at the same time.Figure 6. Lateralprojection for mandibularpremolars and molar(parallel technique).(A) The tubehead shouldbe centered over themandibular premolars andmolar. Size 2 intraoral film isrecommended. (B) The cat’s Filmhead should be placed inlateral recumbency and aspacer inserted under thejaw to keep the hard palateperpendicular to the planeof the table top. Size 2intraoral film can then be A Bplaced in the vestibulebetween the tongue and mandible, making sure that the film does not traumatize the symphyseal area during insertion and removal. The x-ray cone shouldbe positioned perpendicular to the film and teeth at an angle of about 60˚ to the horizontal plane or table top. The primary x-ray beam will be almostperpendicular to the film and teeth. HARTZ® COMPANION ANIMALSM • NOVEMBER 2006 • VOL. 4, NO. 4 7
  8. 8. ASK THE VET (continued from page 5)Which Hartz products have the Veterinary Oral Health • Braided rawhides—Longer lasting and have the stick shape thatCouncil acceptance seal? dogs love.The Veterinary Oral Health Council (VOHC) exists to recognize • Twists with two different flavors—Provide twice the flavorproducts that meet standards of plaque and calculus retardation in dogs and are longer lasting than plain strips.and cats. Products are awarded the VOHC Seal of Acceptance followingreview of data from trials conducted according to VOHC protocols. The • Munchy rawhide treats—Quick crunchy treats that are greatVeterinary Oral Health Council has given its seal of acceptance to the for senior pets because they are easier to chew.Hartz® Chew-Dent™ Infused Rawhide product for dogs. • Long rawhide rolls—Dogs enjoy “fetching” these like they would a stick.How do you choose the appropriate rawhide for a dog?There are many shapes and flavors of rawhide available on the • Pressed rawhides—Made from layers of rawhide skin pressedmarket. Choosing rawhide with HMP will help provide better dental together by a machine; these are great for very aggressivebenefits. Also, dogs with tendencies for food aggression should be chewers, as the rawhide is compressed and keeps the doggiven any treat, including rawhide, cautiously and never in the chewing longer.presence of other animals. How can I learn more about rawhide and dentalThe following quick guide can help you choose the correct treat for care for dogs?your pet: If you would like to receive copies of the Hartz® Dental Brochures and free samples of Hartz® Dental rawhide products, you can call• Pencil-shaped rawhides—Smaller dogs like to chew on one 800-275-1414 (9 AM to 5 PM EST) or email dental@hartz.com. end while holding the other end with their paws. The pencil tip helps clean teeth when the dog chews on it.• Bone-shaped rawhides—Last longer than sticks or chips. REFERENCES Thicker bones can keep a dog chewing longer. 1. Effect of chewing rawhide and cereal biscuit on removal of dental calculus in dogs. JAVMA 197(2):213–219, 1990.• Chips—Quick chewy treats that can be given as rewards. The chips 2. Effect of sodium hexametaphosphate on dental calculus formation in are usually eaten more quickly than the bone-shaped rawhides. dogs. Am J Vet Res 56(7):913–918, 1995.Veterinary Learning Systems PRST STD780 Township Line Road U.S. POSTAGEYardley, PA 19067 PAID YORK, PA PERMIT #200 402348