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Dentistry Sandra Manfra Marretta, DVM, Diplomate ACVS, AVDC University of Illinois Decision Making and Techniques to Simplify Dental Extractions in Dogs Decision making and techniques to simplify dental extractions in dogs have been described.1-5 Proper perioperative planning and decision making regarding canine extractions can improve surgical outcome. Preoperative Considerations in the Canine Dental Patient It is important to properly assess the canine patient prior to the performance of extractions. This includes complete general physical and oral examinations and appropriate preoperative blood work. Once the patient has been properly assessed it is important to select an appropriate anesthetic protocol that will provide the canine dental patient with adequate perioperative pain management. Oral Examination in the Awake Canine Patient Oral examination in the awake canine patient is similar to the oral examination in the awake feline patient. Abnormalities detected are discussed with the owner with the stipulation that additional abnormalities may be detected in the anesthetized patient. Oral Examination in the Anesthetized Canine Patient Oral examination in the anesthetized canine patient begins with a thorough oral examination including evaluation for missing or supernumerary teeth, malformed teeth, proper occlusion, periodontal probing and exploration of the teeth with a dental explorer to detect pulpal exposure, worn teeth and dental caries. Abnormalities are noted on the canine dental chart. Dental Radiography in the Canine Patient Prior to Extraction Dental radiography is an important tool in the decision making process in canine dental patients. Dental radiography can help determine the most appropriate treatment modality in canine teeth affected with periodontal disease, endodontic disease, dental caries and other lesions. A dental radiograph taken prior to performing a difficult extraction will provide the veterinarian with important information regarding the tooth. Radiographic evaluation of the tooth will determine if other treatment options may be possible so that the owner can be offered alternatives to extraction. In cases of severe periodontal or endodontic disease extraction may be the best treatment option for the patient. Dental radiographs prior to extraction will also reveal structural abnormalities that might be present in the tooth or surrounding bone. These structural abnormalities include: severe periradicular bone loss secondary to periodontal or endodontic disease, supernumerary roots, abnormal root angulation including convergent roots and excessive curvature of the apical portion of the root, ankylosis and hypercementosis. Knowledge of these structural abnormalities prior to initiation of the extraction will provide important information regarding the most appropriate technique for the extraction and will help reduce the incidence of complications. Proper Equipment and Instrumentation for Canine Extractions A high-speed handpiece with fiberoptics is extremely helpful when performing surgical extractions in dogs. The fiberoptic handpiece provides a light source directly on the surgical site. Burs utilized frequently include a variety of round burs for the removal of buccal bone and tapered fissure burs for sectioning multi-rooted teeth. Essential hand instrumentation for performing canine extractions have been previously described.1-5 Hand instrumentation specifically designed for canine extractions is available through numerous veterinary supply companies. Instruments for canine extractions may be packaged together in a canine extraction pack and steam sterilized prior to each use. Instrumentation in canine extraction packs include: scalpel handle upon which a #15 blade can be placed prior to surgery, a periosteal elevator, a soft tissue retractor, a variety of dental elevators and luxators, extraction forceps, needle holders, Adson tissue forceps, suture scissors and an iris scissors for cutting soft tissue. A small root forceps is also helpful for reaching down into an alveolus and obtaining a firm grasp on a loose root tip. It is imperative to routinely sharpen dental extraction instrumentation to insure optimal functionality. Anatomic Features of Canine Teeth The dental formula in the adult dog is: 2 (I 3/3, C1/1, P4/4, M2/3) = 42. The incisors and canine teeth all have one root. The 1st premolars and the lower 3rd molars have one root. The upper 2nd and 3rd premolars and the lower 2nd,3rd 4th premolars and 1st and 2nd premolars have two roots and the upper 4th premolar and 1st and 2nd molars have 3 roots. Knowledge of the location of the furcation of the teeth will permit accurate sectioning of teeth during surgical extractions. Techniques for Performing Simple and Multi-Rooted Extractions in Dogs There are several different techniques for performing extractions in the dog. These techniques include a simple extraction, multi-rooted extraction and surgical extraction Simple or Closed Extraction The incisors, the maxillary and mandibular 1st premolars and the mandibular 3rd molar are generally small single rooted teeth in the dog and can be usually be removed using simple or closed extraction techniques. Simple or closed extraction techniques have been previously described.1-5 The procedure is initiated by cutting the gingival attachment around the whole circumference of the tooth using a No. 11 scalpel blade in a handle or a sharp luxator. A luxator that matches the curvature of the tooth is selected and is placed into the gingival sulcus at a slight angle to the tooth and pressed into the periodontal ligament space and worked around the entire circumference of the tooth using gentle apical pressure. The operator may now elect to continue the extraction using a dental elevator or continue using a luxator. A dental elevator may be used once adequate space has been created for the thicker tipped instrument. An appropriate sized elevator is selected, placed in the periodontal ligament space and worked around the tooth with a gentle rotational pressure held at each point for 10-15 second to help break down the periodontal ligament. Once the tooth becomes loose it can be removed digitally or gently grasped with a dental extraction forceps placed as far apically on the tooth as possible and with a gentle rotational movement of the forceps in the long axis of the tooth, the tooth may be rotated and removed from the alveolus. Multi-Rooted Extraction Extraction of multi-rooted teeth in dogs begins by cutting the gingival attachment to the tooth with either a No. 11 or 15 scalpel blade in a handle or an appropriately sized sharp luxator. The furcation(s) of the tooth are located using visual inspection of the gingiva and alveolar crest. Furcations may be located by observing where the gingiva and alveolar crestal bone raises slightly coronally. Removal of a small amount of bone in this area with a round bur will help visualized the furcation. Once the furcation is visualized the tooth is sectioned by placing a tapered fissure bur (#701 or #701L) at the furcation and sectioning the tooth through the crown. One cut is made in 2 rooted teeth and two cuts are made in 3 rooted teeth to divide the tooth into multiple single units. To confirm that the tooth has been successfully sectioned, a dental elevator is placed between the segments and gently rotated. If the segments move slightly apart then the sectioning is complete; if the segments do not move following slight leverage between the cusp segments then the sectioning is likely to be incomplete and addition burring is necessary to complete the sectioning. Once the sectioning is complete the individual roots are extracted independently as previously described for simple extractions. Techniques for Performing Surgical Extractions in Dogs A complicated or surgical extraction technique is generally reserved for teeth that are difficult to extract because of their large root structure including the canine teeth, mandibular 1st molars and the maxillary 4th premolars. A surgical extraction may also be performed when teeth are ankylosed or when attempting to retrieve a broken root tip. The teeth most commonly requiring surgical extractions include the canine teeth and the carnassial teeth. Surgical Extraction of Canine Teeth Surgical extraction of the maxillary canine tooth is initiated by making divergent incisions mesial and distal to the canine tooth and creating a mucoperiosteal flap. The buccal alveolar bone is removed as needed with a large round bur to easily extract the tooth with luxators and dental elevators. Care should be taken to avoid creating an oronasal fistula during the extraction. The periosteal layer of the flap is incised apically to relieve tension on the flap prior to closure. There are two approaches for the surgical extraction of the mandibular canine teeth including the labial and lingual approach. The labial approach utilizes a mucoperiosteal flap located on the labial aspect of the tooth while a lingual approach utilizes a lingually located flap. Equal amounts of alveolar bone are present buccally and labially so there is no advantage of one technique over the other with regard to bone removal. The mental artery, vein and nerve exit through the mental foramen located near the labial aspect of the apex of this tooth. A lingual approach avoids potential damage to these structures. Surgical Extraction of the Maxillary 4th Premolars When performing a mucoperiosteal flap for the surgical extraction of the maxillary 4th premolar several structures should be carefully avoided. When making the mesial (rostral) portion of the incision the infraorbital artery, vein and nerve should be avoided as they exit the infraorbital canal immediately rostral to the periapical bone of the mesiobuccal root of the maxillary 4th premolar. These structures can be avoided by digitally retracting them dorsally and not extending this incision too far apically. When making the distal (caudal) part of the incision the parotid and zygomatic salivary duct papillae should be visualized and avoided. After raising the mucoperiosteal flap the furcations are located using a round bur. The tooth is then sectioned through the furcation between the mesiobuccal and distal roots with a #701L tapered fissure bur from the furcation through the crown. Alveolar bone over the distal root is removed as needed to remove the distal root. At this point some operators prefer to amputate part of the remaining portion of the crown. The bur is placed in the furcation perpendicular to the tooth at the base of the palatal wall of the mesiobuccal cusp to section the mesiobuccal and palatal roots. The alveolar bone over the mesiobuccal roots is removed as needed to remove the mesiobuccal root. The interradicular bone between the mesiobuccal and palatal roots can be removed as needed to expose the palatal root. When extracting the palatal root it is important to direct the luxator in a slightly palatal direction to follow the palatal direction of the apex of this root. The extraction site is débrided, flushed and closed in a routine manner. Surgical Extraction of the Mandibular 1st Molars The surgical extraction of the mandibular 1st molar is initiated with a mucoperiosteal flap with two divergent releasing incisions on the mesial and distal aspect of the buccal aspect of the tooth. The mucoperiosteal flap is raised and the furcation is located and sectioned. The distal and mesial edges of the cusps of the tooth may be removed to provide straight access to the periodontal ligament space. This is particularly helpful in teeth that are crowded. Buccal alveolar bone is removed as needed to extract the segments. Rough edges of the alveolar bone are reduced with a large round bur, the extraction site is débrided and flushed with sterile saline. The periosteal layer of the flap is released and the flap is closed in a simple interrupted manner. Extraction of Fractured Root Tips Surgical techniques for extraction of fractured root tips has been described.6 When a tooth root fractures it should be determined if the root must be retrieved and in most cases root fragments should be completely removed. Roots of endodontically and periodontally diseased teeth must be removed. However, teeth undergoing severe bony replacement/odontoclastic resorption may be best treated conservatively. When extracting fractured tooth roots a mucoperiosteal flap is raised and some of the buccal alveolar bone over the retained root is removed. When attempting to localize the fractured root the operator should examine the extracted coronal segment to mentally determine the anatomic features of the residual root structure. In addition, the operator should look for a white, hard, non-bleeding structure with a central pulpal red or black spot. Dental radiographs can help locate the fractured root tips. Other techniques that have been described include using the flat end of a cylindrical diamond bur on a high-speed handpiece to flatten the coronal aspect of the fractured root and a small area of the surrounding bone until the root is clearly visible in cross-section.6 A small round bur (# 1/2) is used to create a "gutter" or space around the root to place an elevator into the expanded PDL space.6 It is important to locate the periodontal ligament space while elevating a root because failure to locate this space often results in inappropriate placement of the dental elevator or luxator either on the alveolar bone or tooth. Elevation on the alveolar bone or tooth is ineffective and until the dental elevator or luxator is directed into the periodontal ligament space removal of the root will not proceed efficiently. A luxator is placed in the space and gently rotated and held for 10-20 seconds around the entire circumference of the root. The periodontal ligament space will fill with a small amount of blood and can be observed as a thin red line located between the alveolar bone and the root. The dental elevator or luxator should be directed into this space to permit more effective elevation and efficient extraction of the root until it becomes loose and is easily extracted. The surgical site is débrided, flushed and closed routinely. References:
Decision Making and Techniques to Simplify Dental Extractions in Cats Decision making and techniques to simplify dental extractions in cats have been previous described.1-5 Proper perioperative planning and decision making regarding feline extractions can improve surgical outcome. PREOPERATIVE CONSIDERATIONS IN THE FELINE DENTAL PATIENT It is important to properly assess the feline patient prior to the performance of extractions. This includes complete general physical and oral examinations and appropriate preoperative blood work. Once the patient has been properly assessed it is important to select an appropriate anesthetic protocol that will provide the feline dental patient with adequate perioperative pain management. ORAL EXAMINATION IN THE AWAKE FELINE PATIENT It may be difficult to perform a thorough oral examination in the awake feline patient however it is important to attempt to assess the oral cavity in the cat as completely as possible to help determine the general oral health of the patient. It must be remembered that all of the oral and dental lesions will not be readily apparent in the awake feline patient and a thorough oral examination including dental radiographs under anesthesia will be necessary to detect the full extent of the dental lesions. An oral exam is initiated by placing both hands gently around the patient's head and neck and then gently parting the lips with the thumbs to visualize the buccal aspect of the canine teeth and cheek teeth on each side. The incisor and canine teeth may be visualized from the front of the patient using the index fingers and thumbs to retract the lips. The maxilla is then visually assessed for any evidence of asymmetry or swelling. The eyes and nostrils are evaluated for any signs of asymmetry or discharge. The mandibles are then palpated for any evidence of swelling or asymmetry. The mouth is then gently opened by placing the index finger and thumb of the nondominant hand just below the zygomatic arches and tilting the patient's nose dorsally and then carefully placing the tip of the opposite index finger over the lower incisor teeth and gently pushing ventrally to open the mouth to permit visualization of the tongue, palate and pharynx. The thumb of the dominant hand is then placed in the intermandibular space with the index finger still on the lower incisors to displace the tongue dorsally to permit examination of the ventral aspect of the tongue. Abnormalities detected are discussed with the owner with the stipulation that additional abnormalities may be detected in the anesthetized patient. ORAL EXAMINATION IN THE ANESTHETIZED FELINE PATIENT Evaluation of the anesthetized feline patient begins with a thorough oral examination including evaluation for missing or supernumerary teeth, malformed teeth, proper occlusion, periodontal probing and exploration of the teeth with a dental explorer to detect pulpal exposure and resorptive lesions. Abnormalities are noted on the feline dental chart . DENTAL RADIOGRAPHY IN THE FELINE PATIENT PRIOR TO EXTRACTION Dental radiography is an important tool in the decision making process in feline dental patients. Dental radiography can help determine the most appropriate treatment modality in feline teeth affected with periodontal disease, endodontic disease and feline resorptive lesions. Radiographic Changes Associated with Feline Periodontal Disease Requiring Extraction Dental radiographs demonstrating less than 50% of attachment remaining on any mobile tooth indicates that extraction is indicated. In addition if dental radiographs indicate that there is loss of attachment to the apex of a single-rooted tooth or loss of attachment to the apex of any root of a multi-rooted tooth then extraction is indicated. Radiographic Changes Associated with Feline Endodontic Disease Requiring Extraction or Endodontic Treatment The presence of endodontic disease or disease of the pulp of a feline tooth requires extraction or endodontic therapy. Radiographic changes associated with endodontic disease include loss of tooth structure to the pulp of the tooth, asymmetrical endodontic canals, periapical lysis or apical lysis. Radiographic Changes Associated with Feline Odontoclastic Resorptive Lesions Requiring Extraction or Crown Amputation with Intentional Root Retention Dental radiography is extremely important in the assessment of feline odontoclastic resorptive lesions since the selection of the appropriate treatment is based on proper evaluation of the dental radiographs. Feline teeth with advanced root resorption, without periodontal or endodontal lesions are good candidates for crown amputation with intentional root retention.5 Conversely, a tooth with a feline odontoclastic resorptive lesion that has a well-defined periodontal ligament space, bone loss due to periodontitis, or a periapical lesion evident on radiographs requires standard extraction techniques with complete removal of the roots.5 In individual feline teeth in which one root has an advanced root resorptive lesion and another root has a well-defined periodontal ligament space it is acceptable to perform a crown amputation with intentional root retention on the root that has severe resorption and perform a routine extraction of the root that has a well-defined periodontal ligament space. PROPER EQUIPMENT AND INSTRUMENTATION FOR FELINE EXTRACTIONS A high-speed handpiece with fiberoptics is extremely helpful when performing surgical extractions in cats. The fiberoptic handpiece provides a light source directly on the surgical site. Burs utilized frequently include small round burs for the removal of buccal bone and tapered fissure burs for sectioning multi-rooted teeth. Essential hand instrumentation for performing feline extractions have been previously described.1-5 Hand instrumentation specifically designed for feline extractions is available through numerous veterinary supply companies. Instruments for feline extractions may be packaged together in a feline extraction pack and steam sterilized prior to each use. Instrumentation in feline extraction packs include: scalpel handle upon which a #15 blade can be placed prior to surgery, a small feline periosteal elevator, a soft tissue retractor, a variety of dental elevators and luxators, small extraction forceps, small needle holders, Adson tissue forceps, suture scissors and an iris scissors for cutting soft tissue. A small root forceps is also helpful for reaching down into an alveolus and obtaining a firm grasp on a loose root tip. It is imperative to routinely sharpen dental extraction instrumentation to insure optimal functionality. ANATOMIC FEATURES OF FELINE TEETH The dental formula in the adult cat is: 2 (I 3/3, C1/1, P3/2, M1/1) = 30. The anatomy of the mouth and teeth of the cat has been previously described.6 Feline teeth are much smaller and narrower than canine teeth. All the incisors and canine teeth have one root. The small maxillary second premolar usually is a small single-rooted tooth which may have two roots which may be fused together. The maxillary 3rd premolar has 2 roots with a supernumerary root sometimes present, the maxillary 4th premolar has 3 roots and the maxillary 1st molar is very small with two roots that may be fused. There are 3 mandibular cheek teeth. The 3rd and 4th premolars each have two symmetrical roots and the 1st molar has two asymmetrical roots with a large mesial root and a small distal root. TECHNIQUES FOR PERFORMING FELINE EXTRACTIONS There are several different techniques for performing feline extractions. These techniques include a simple extraction, multi-rooted extraction, single-rooted surgical extraction, partial or full-mouth extractions for the treatment of feline stomatitis, and crown amputation with intentional root retention for the treatment of feline resorptive lesions. Simple or Closed Extraction The incisors, the maxillary 2nd premolar and the maxillary molar teeth are generally small single rooted teeth in the cat and can be removed using simple or closed extraction techniques. Simple or closed extraction techniques have been previously described.1-5 The procedure is initiated by cutting the gingival attachment around the whole circumference of tooth using a No. 11 scalpel blade in a handle or a sharp luxator. A luxator that matches the curvature of the tooth is selected and is placed into the gingival sulcus at a slight angle to the tooth and pressed into the periodontal ligament space and worked around the entire circumference of the tooth using gentle apical pressure. The operator may now elect to continue the extraction using a dental elevator or continue using a luxator. A dental elevator may be used once adequate space has been created for the thicker tipped instrument. An appropriate sized elevator is selected, placed in the periodontal ligament space and worked around the tooth with a gentle rotational pressure held at each point for 10-15 second to help break down the periodontal ligament. Once the tooth becomes loose it can be removed digitally or gently grasped with a small dental extraction forceps placed as far apically on the tooth as possible and with a gentle rotational movement of the forceps in the long axis of the tooth, the tooth may be gently rotated and removed from the alveolus. Multirooted Extraction Extraction of multirooted teeth in cats requires additional consideration because of the tendency for these roots to fracture during extractions. A modified technique for extracting multirooted teeth in the cat has been reported.2 This technique involves raising both buccal and lingual flaps and removing adequate alveolar bone to expose the furcation. The furcation is then sectioned using a size 2 round bur making two cuts from the furcation at 450, one distally and one rostrally thereby removing a significant portion of the crown leaving only a small portion of the crown mesially and distally. A size 2 or 4 round bur is then used to remove the interradicular bone between the mesial and distal roots to the apical region of the roots without invading the nasal cavity or mandibular canal. This results in support of the roots by 3 sides. An appropriately sized luxator or elevator can be eased into the interradicular space created by the bur and into the periodontal ligament of the roots to gently remove the roots independently. Additional buccal bone may be removed as necessary. Sharp edges of bone are removed with a small round bur, the surgical site is flushed and the flap is closed with 4-0 chromic or 4-0/5-0 poliglecaprone on a small reverse cutting needle. Single-Rooted Surgical Extraction The canine tooth in cats often requires a surgical extraction. The maxillary canine tooth can be removed through a labial flap with two releasing incisions with a broad base. Minimal bone is removed over the labial aspect of the tooth to permit delivery of the tooth using the luxators and dental elevators as previously described. Extraction of the mandibular canine tooth in the cat can be performed using a labial, lingual or alveolar marginal approach. The labial approach utilizes a labial flap with labial bone removal, the lingual approach utilizes a lingual approach with lingual bone removal and the alveolar marginal approach uses a dorsal approach to the canine root through a single incision over the root of the tooth from the distal aspect of the canine tooth distally toward the mesial aspect of the mandibular 3rd premolar. In this approach the bone is removed over the root along the alveolar ridge in the edentulous space between the canine tooth and the 3rd premolar. Care must be taken when elevating this root to direct the elevator along the sides of the root and not straight down the distal aspect of the tooth since this type of elevation will direct the elevator into the root of the canine tooth instead of into the periodontal ligament space. Care must also be taken when extracting the mandibular canine teeth in cats to not apply excessive rotational forces with the elevator since this may result in mandibular fractures. Partial or Full-Mouth Extractions for the Treatment of Feline Stomatitis In cases of feline gingivostomatitis in which medical management is unsuccessful, extraction of all premolars and molars or full-mouth extraction is the treatment of choice. This is facilitated by making a full-thickness gingival flap in each quadrant, using a small feline periosteal elevator to elevate the lingual and/or palatal and buccal aspects to provide adequate exposure to the underlying bone. The buccal bone is removed as needed, the teeth are sectioned and removed as previously described. The rough edges of bone are removed with a small round bur, the alveoli are curettaged, the surgical site is flushed and the surgical site closed without tension. Crown Amputation with Intentional Root Retention for Treatment of Feline Resorptive Lesions Properly screened teeth with feline resorptive lesions can be treated by crown amputation with intentional root retention. Pre-extraction radiographs are imperative in case selection. Teeth with advanced root resorption, without periodontal or endodontal lesions, are good candidates for crown amputation with intentional root retention. Teeth with an intact periodontal ligament and no severe root resorption or teeth with periodontal or endodontal lesions or cats with stomatitis require routine extractions. The procedure is initiated by making a small mucogingival flap and amputating the crown with a small round diamond burr on a high-speed handpiece. The site is checked with a dental explorer to insure complete amputation of the entire crown. Any residual crown and irregular alveolar bone is removed with the round burr. The residual pulp in the surgical will bleed on appropriately screened teeth. The site is flushed and closed. COMPLICATIONS ASSOCIATED WITH EXTRACTIONS Complications associated with extractions include the following: root fracture, hemorrhage, delayed wound healing and infection, oronasal fistula, ocular injuries, salivary duct injury, misplacement of roots fragments into the nasal cavity or into the mandibular canal, damage to adjacent teeth and mandibular fracture. Careful extraction techniques and appropriate perioperative management can help minimize these complications. REFERENCES:
An Update on Periodontal Disease in Dogs 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. 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 Stages of Periodontal Disease In Stage 1 (gingivitis) periodontal disease, gingivitis with no attachment loss is present. Some dogs may have significant dental calculus with minimal gingivitis while others may have severe inflammation with minimal plaque and calculus. This stage of periodontal disease results in inflammation, edema, plaque and calculus accumulation, possible bleeding on probing, and possible pseudopocket formation.5 In Stage 2 (early) periodontal disease, the initial signs of destructive periodontitis are evident. Periodontal probing and radiographic examination may indicate attachment loss of up to 25%, teeth remain stable and pocket depths of 3-5mm are present.6 In Stage 3 (moderate) periodontal disease, the probing and radiographic signs of attachment loss are between 25% and 50% of the root length.6 Probing depths of 6-9 mm may be present with the presence of vertical defects and infrabony pockets. If gingival recession is present there may be only a minimal increase in probing depth indicating the importance of assessing attachment loss not only by pocket depth but also by measuring attachment loss from the cementoenamel junction to the depth of the periodontal pocket. Teeth may be mobile. In Stage 4 (severe) periodontal disease, the attachment loss is greater than 50%, there is severe loss of supporting tooth structures and pocket depths are greater than 9mm and teeth become loose. Significant infrabony pockets may be localized to a single area, such as the deep palatal pockets seen in maxillary canine teeth.6 Diagnosis of the various stages of periodontal disease is based on a thorough oral examination, periodontal examination with a periodontal probe, and dental radiography. Animals with gingivitis, the reversible form of periodontal disease, have a swollen gingival margin that will bleed after the application of light pressure. Serous or purulent exudate is produced from the gingival sulcus. Halitosis is commonly present. Periodontal examination with a periodontal probe is normal and radiographically there is no evidence of bone loss around the teeth. Periodontitis in dogs is usually characterized by hyperplasia, gingival recession and pocket formation which progresses to tooth loss if untreated. Severe gingival inflammation with various amounts of calculus and debris are present with periodontitis. Periodontal probing will reveal the presence of periodontal pockets. Dental radiographs will reveal bone loss which is associated with periodontal disease. Bone loss may be horizontal or vertical. Horizontal bone loss is bone loss parallel to the cementoenamel junction which separates the anatomic crown from the anatomic root. Vertical bone loss is bone loss parallel to the long axis of the root. 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, periodontopathogen vaccine, 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. 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. 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 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. 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. 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). Freeze-dried canine or feline bone may also be used. After placement of the bone graft material 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. 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 Doxirobe is 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. Periodontopathogen Vaccine Recently, the development of a trivalent canine periodontitis vaccine has provided veterinarians with an additional treatment option in the management of canine periodontitis. Incorporation of this new vaccine into a treatment plan may help prevent periodontitis in dogs. When considering the incidence of periodontitis in dogs, the serious local and potential systemic effects of the disease on our patients, the lack of owner compliance, product safety, and the potential degree of protection provided by a vaccine, vaccination is recommended, particularly in patients at high risk for developing periodontitis. 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 maxillary premolars and molars. Teeth affected with Stage IV periodontal disease should be removed and the oronasal or oroantral fistula should be repaired with a mucoperiosteal flap. 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. References:
Digital Dental Radiography Dental radiography is an essential component in the delivery of high quality dental care for dogs and cats. During the 1980s veterinarians began taking radiographs of teeth using standard radiographic units however these units made patient positioning difficult and often resulted in suboptimal films. In the 1990s dental radiographic units became a more common part of the veterinary dental diagnostic workup and by the year 2000 many state-of-the-art veterinary practices were switching over to digital dental radiography. This seminar will focus on the value of taking dental radiographs, how to take digital dental radiographs, special features available with digital dental radiographic units, advantages and disadvantages of digital dental radiography, indications for taking dental radiographs, positioning for optimal dental radiographs, critiquing dental radiographs and the importance of recognizing dental radiographic lesions. The diagnostic value of full mouth dental radiography in dogs and cats has been previously reported.1,2 It was found that the diagnostic yield of full mouth radiographs in feline and canine patients is high, and routine full mouth radiography is justified. These studies found that if disease existed, radiographs were clinically useful in 86.1% of the cases in the study (Table 1 & 2).1-3 VALUE OF RADIOGRAPHS WHEN NO CLINICAL FINDINGS PRESENT
Table 1 VALUE OF RADIOGRAPHS WHEN CLINICAL FINDINGS PRESENT
Table 2 How to Take Digital Dental Radiographs and Special Features Available There are two methods of acquiring digital dental radiographs, either DR (Digital Radiography) or CR (Computer Radiography). DR images are acquired by placing a sensor into the mouth in the same position as a film and exposing the sensor with a greatly reduced dose of radiation. The image is transferred within seconds for viewing on a computer. These images are then electronically stored and manipulated as needed for radiographic evaluation of a wide variety of dental lesions. CR images are an indirect way of acquiring digital dental radiographs. With this technology a reusable Phosphor Storage Plate (PSP) is exposed to x-rays and the PSP is then processed and converted to a digital image on a computer. The Scan X®, a digital radiography system, produces a digital image by scanning PSPs of various sizes (0,2,3 and 4) which have been exposed to x-rays. The Scan X® allows computer storage, processing, retrieval and display of the computed radiographic images utilizing a user supplied software package. The Scan X® also has an in-line plate eraser function that removes the latest image from the plate immediately after scanning providing an efficient one-step scanning and erasing process leaving the PSP ready for the collecting the next radiographic image. Digital dental radiographs can be manipulated for better visualization. The mouse can be used to adjust the contrast and brightness, a particular area of a tooth can be highlighted, magnified, labeled, flipped, rotated, measured or explanatory notes can be added . The advantages and disadvantages of digital dental radiography have been previously reported.3,4 Advantages of Digital Dental Radiography
Ideally full mouth radiographs should be taken on every patient, however, this may not be possible because of cost constraints or concerns for time under anesthesia in critically ill patients. Digital radiographs can help alleviate f these concerns because of the decrease in time needed to acquire digital radiographs. If full mouth radiographs are not taken there are several indications in which teeth should be radiographed. Dental radiography is recommended in the evaluation of odontoclastic resorptive lesions, the evaluation of periodontal disease including animals with nasal discharge, the evaluation of endodontic disease including discolored teeth and facial swelling, retained roots, missing teeth, abnormally located teeth, malformed teeth, osteomyelitis, boney lysis secondary to neoplasia, metabolic bone disease, localization of dentigerous cysts, and evaluation of traumatic injuries. Dental radiography is indispensible in the development of an appropriate treatment plan. Positioning for Optimal Dental Radiographs There are numerous publications that describe appropriate positioning for optimal dental radiographs.3-8 There are two specific intraoral radiographic dental techniques: the parallel technique and the bisecting angle technique. The ideal dental radiograph is produced by utilizing the parallel technique. When using the parallel technique the plane of the radiographic film is parallel to the long axis of the tooth and perpendicular to the plane of the radiographic beam. The parallel technique in dogs and cats can only be achieved with the mandibular premolars and molars. The flat shallow palate and the shallow caudally extending mandibular symphysis in dogs and cats prevent utilization of the parallel technique when radiographing the maxillary premolars and molars and the incisor and canine teeth. In these teeth the bisecting angle technique can be utilized. The film is placed as parallel as possible to the teeth being radiographed. An imaginary line that bisects the angle between the long axis of the tooth and the film is the bisecting angle line. The x-ray beam should be directed perpendicular to the bisecting angle line. Improper utilization of the bisecting angle technique will result in an elongated, foreshortened, or an overlapped radiographic dental image. A basic dental radiographic survey consists of six views: the rostral maxillary and mandibular projections, the right and left maxillary projections and the right and left mandibular projections. Additional radiographs may be necessary depending on the size of the patient. The upper fourth premolar requires additional radiographs to permit adequate visualization of all three roots. A 30-degree rostral oblique projection needs to be added to the bisecting angle technique to permit adequate visualization of the mesiobuccal and palatal roots. Critiquing Dental Radiographs Various organizations including the American Veterinary Dental College and the Academy of Veterinary Dentistry require dental radiographs for evaluation. Striving to follow these established guidelines will produce meaningful diagnostic films. These guidelines which have been previously published can be used as a guide to assist in self-evaluation of radiographs.3
Proper evaluation of feline teeth with odontoclastic resorptive lesions can help determine the appropriate treatment option including either routine extraction or crown amputation with intention root retention. When retained roots are identified with dental radiography a decision to retrieve or retain these roots must be made. If the retained roots are an incidental finding in a patient that is asymptomatic and there is no evidence of periapical or apical lysis around the retained root tip and the root is covered by normal gingiva that is epithelized than no treatment is recommended. However, if the patient is symptomatic, there is an area of granulation tissue over the retained root tip or radiographically there is evidence of periapical or apical lysis than removal of the root is recommended. Dental radiographs can be used to assess bone loss secondary to periodontal disease and help determine the most appropriate treatment plan. In cases in which there is greater than either 50-75% attachment loss or bone loss to the apex of a single root of a multi-rooted tooth is revealed on the dental radiographs, extraction is generally recommended. Dental radiography can be used to evaluate for the presence of endodontic disease Abnormal radiographic findings associated with endodontic disease include: periapical lysis, apical lysis, large endodontic systems secondary to failure in normal development or resorption, radiographic loss of tooth structure to the pulp canal and secondary destruction of the periodontium. Periapical lysis appears as a dark halo around the apex of the roots caused by lysis of the bone around the apex of the tooth associated with endodontic disease. Apical lysis is lysis of the apex or tip of the root itself. Apical lysis is associated with chronic endodontic disease. It is important to recognize the presence of apical lysis since apical lysis precludes the performance of conventional root canal therapy alone and necessitates the performance of surgical endodontic therapy in combination with conventional endodontic therapy or exodontia. Large or asymmetrical endodontic systems may be secondary to failure in normal development from early pulpal death from endodontic disease or may be secondary to internal resorption from pulp damage. The canals of affected teeth may be larger then the contralateral canals or larger than the canals of adjacent teeth or may be asymmetrical within a solitary affected tooth. Chronic endodontic disease can result in secondary destruction of periodontal structures along the root of a tooth with pulpal necrosis. Dental radiography is recommended in the evaluation of missing teeth. In puppies with missing deciduous teeth a dental radiograph may be taken to determine if a permanent tooth bud is present. Early determination of the absence of a permanent tooth bud will help breeders determine if a dog is either show or pet quality. Dental radiography can also reveal the location of teeth that have been misplaced following trauma. Teeth that appear malformed require dental radiographs to help determine the presence of endodontic disease. Developmental abnormalities such as dens-in-dente in which the enamel is enfolded may result in secondary endodontic disease. This condition appears to most frequently affect the lower 1st molar in the dog and often occurs bilaterally. These teeth appear to have an increased radiodensity in the crown, convergence of the roots, large pulp canals and the presence of periapical lysis. Osteomyelitis may be detected radiographically. Osteomyelitis may be secondary to severe periodontal disease, endodontic disease or trauma. Osteomyelitis may appear as an increased bony density with loss of detail and periosteal reaction. Osteomyelitis should be treated by removal of diseased teeth and bony sequestra, and appropriate long term antibiotic therapy. Radiographs should be taken in animals with multiple loose teeth in one region of the oral cavity. Severe boney lysis and displacement of teeth is suggestive of a malignant tumor. Biopsy of these lesions is required for a definitive diagnosis and for appropriate treatment planning. Metabolic bone diseases, such as renal secondary hyperparathyroidism can be evaluated with dental radiographs. The initial radiographic finding associated with hyperparathyroidism is loss of the lamina dura which is the cortical plate of the alveolus that surrounds the tooth roots. As the disease progresses there is a loss of density of trabecular and cortical bone. Dental radiographs are essential in the diagnosis of dentigerous cysts. When oral examination of dental patients reveals a soft, fluid filled gingival swelling in the region of a missing tooth a dental radiograph is recommended. Radiographs may reveal the presence of a dentigerous cyst which appears as a smooth-bordered radiolucent cavity typically adjacent to the cementoenamel junction of the unerupted, misplaced tooth. Dental radiographs are important in the perioperative management of jaw fractures. Preoperative radiographs will assist in the evaluation of the fracture site, determine the location of tooth roots in and around the fracture site and assist the selection of appropriate treatment options. Dental radiographs are also essential in the postoperative evaluation of fracture fixation and reduction and assessment of proper healing of jaw fractures. Summary Dental radiography is an essential component in the daily delivery of high quality dental care for dogs and cats. Recently many state-of-the-art veterinary practices have switched over to digital dental radiography because of the speed and ease in which these images can be produced and evaluated. The real value in taking digital dental radiographs is improved patient care while at the same time providing a profit center for the hospital. The advantages of digital dental radiography far outweigh the disadvantages of this new technology. With proper orientation and training in the use of digital dental radiographic units this new technology can become an integral part of small animal veterinary. Following an appropriate training period veterinarians and veterinary technicians will be able to obtain high quality dental images which will result in the recognition of more lesions which can then be appropriately treated. References
Management of Dental and Oral Trauma A variety of dental and oral lesions can occur as a result of trauma including fractured teeth, subluxated teeth, avulsed teeth and jaw fractures. The management of these injuries can be a diagnostic and therapeutic challenge. Proper management of these injuries can be a rewarding part of veterinary practice. Fractured Teeth Fractured teeth usually result from external trauma. In cats, the tooth most frequently fractured because of trauma is the canine tooth. Fractured canine teeth in cats often result in pulpal exposure because of the extension of the pulp canal into the coronal tip of the canine tooth in felines. Pulpal exposure is confirmed if a fine dental explorer penetrates into the canal. The teeth most frequently fractured in the dog are the canine teeth, incisors, and the maxillary fourth premolars, however, any tooth may be fractured. Following pulpal exposure the following sequence of events may occur: Pulpal exposure?Bacterial pulpitis?Pulp necrosis?Apical granuloma?Periapical abscess?Acute alveolar periodontitis?Osteomyelitis?Sepsis Radiographic evidence of chronic endodontic disease or pulpal necrosis include:
Several different endodontic procedures may be utilized to treat endodontically diseased teeth these techniques include: vital pulpotomy, conventional and surgical endodontic therapy. Whenever pulp disease is present it is important to decide which type of endodontic therapy is most appropriate based on the patient's age, time of exposure, and the gross anatomic features and vitality of the tooth. The most common and most successful type of endodontic therapy is conventional or nonsurgical endodontic therapy. Occasionally vital pulpotomy with direct pulp capping is recommended and rarely surgical or nonconventional root canal therapy is indicated. A vital pulpotomy with direct pulp capping is indicated in vital teeth with traumatic pulpal exposure of less than 8 hours. This permissible exposure time may be extended to up to 2 weeks in very young animals with immature teeth. It is also indicated in crown shortening procedures as an alternative to conventional endodontic therapy in the treatment of mature permanent teeth. Ideally, vital techniques such as vital pulpotomy with direct pulp capping should be limited to use in incompletely developed permanent teeth with pulpal exposure. A vital pulpotomy with direct pulp capping in an animal less than 18 months of age will permit the tooth to remain vital at least temporarily so that additional dentin can be formed resulting in an increase in strength of the tooth that has been fractured. Additionally, it can allow the formation of the apex of a very immature tooth. A pulpotomy with direct pulp capping should never be performed in nonvital teeth, when the pulpal exposure is prolonged and in teeth in which the pulp is severely traumatized or grossly contaminated. In fact, it is best to limit vital pulpotomy procedures to immature teeth with recent exposure and teeth requiring crown reduction procedures. The objective of a vital pulpotomy with direct pulp capping is to protect the pulp following pulpal exposure by stimulating formation of secondary dentin over the pulpal tissue and covering over the access site with a restorative material. The steps involved in the performance of a vital pulpotomy with direct pulp capping are listed below: (1) Preoperative radiograph of the affected tooth and the contralateral tooth. (2) Disinfection of the tooth with 0.2% chlorhexidine solution. (3) An appropriately sized sterile diamond pear-shaped bur on a high speed handpiece is used to remove the coronal portion of the pulp. (4) The remaining pulp is gently flushed with sterile saline and the blunt end of paper points are used to achieve hemostasis. (5) A layer of MTA (a new pulp capping material) is gently placed over the pulp. (6) An intermediate layer of glass-ionomer is placed over the MTA. (7) A composite material is used to fill the access site. Postoperative care for animals following a vital pulpotomy with direct pulp capping includes antibiotic therapy for 1 week postoperatively. Owners should be informed that a vital pulpotomy with direct pulp capping may necessitate conventional endodontic therapy in the future if pulpitis and pulpal necrosis develops. The patient should be monitored for clinical signs associated with endodontic disease. Oral examination by the owner and veterinarian may reveal problems associated with a failed vital pulpotomy with direct pulp capping including: discolored teeth, soft tissue fistulas, teeth that are painful on percussion or lost restorations. Dental radiographs should be taken at 6 and 12 month intervals postoperatively and then annually during regular dental appointments. Radiographic findings indicative of pulpal necrosis include: periapical or apical lysis, failure of symmetrical dentin deposition compared to the contralateral normal tooth and endodontic resorption. Radiographic findings consistent with pulpal necrosis necessitate the performance of conventional endodontic therapy or extraction of the affected tooth. Conventional endodontic therapy or nonsurgical endodontic therapy is performed through the crown of the tooth and is the most frequently performed endodontic therapy. This procedure is indicated whenever there is pulpal death of a tooth secondary to inflammation, infection or trauma. The purpose of root canal therapy is to preserve the function of the tooth while preventing it from causing adverse effects because of its presence. This is achieved by removing the necrotic or infected pulp and filling the pulp canal with an inert material. A properly performed root canal procedure will prevent infection or inflammatory products from extending from the tooth into the tissues that surround the apex of the tooth. There are several basic steps involved in performing conventional endodontic therapy. These steps include: (1) preparation, (2) access, (3) debridement, (4) drying, (5) filling, and (6) restoration. Surgical endodontics or nonconventional endodontic therapy refers to the application of endodontic therapy with an approach through soft tissue and bone rather than through the crown of the tooth. Surgical endodontic therapy is always performed in conjunction with nonsurgical or conventional endodontic therapy. Surgical endodontics is not a substitute for good nonsurgical endodontic therapy. The long-term success rate with surgical endodontics has not been shown to be superior to nonsurgical endodontic therapy. A properly prepared and obturated root canal can be adequately sealed with conventional endodontic therapy in most cases. Subluxated and Avulsed Teeth Tooth luxations are the displacement or partial displacement of teeth from their alveoli. Dental avulsions are the loss of teeth from their alveoli. Teeth accidentally avulsed or luxated from their alveoli by trauma should be reimplanted or repositioned as soon as possible, ideally within 30 minutes. Teeth that are luxated or avulsed because of advanced periodontal should not be reimplanted. Until reimplantation of traumatically avulsed teeth is possible, affected teeth may be briefly stored in saliva or milk. Following reimplantation the tooth is held in position with a figure-of-eight wire and an interdental splint. The prognosis for luxated teeth is better than avulsed teeth because of less damage to the periodontal tissues. Endodontic therapy is recommended 2 weeks after correction of luxations and avulsions. In addition, these teeth should be stabilized with an interdental splint for approximately 6 weeks. Jaw Fracture Management Prior to correction of jaw fractures the patient must be thoroughly evaluated for other traumatic injuries. Following stabilization of life-threatening injuries jaw fractures can be evaluated under sedation or general anesthesia. The mandible, maxillofacial bones, and temporomandibular joints are palpated both extra- and intraorally for fractures. Radiographs are taken to localize the fracture sites. It is important to assess the full extent of all injuries keeping in mind that multiple fractures may be present. In cases of severe maxillofacial trauma, computed tomography may be helpful in the recognition of all lesions. The teeth need to be evaluated for periodontal and endodontic disease and their relationship to fracture lines must be determined. Previous reports indicate that pathologic fractures may occur in the mandible of dogs with severe periodontal disease through deep periodontal pockets. These pathologic fractures occur most frequently in the region of the mandibular first molars and canine teeth. Periodontally diseased teeth in a fracture line need to be extracted or hemisected to remove the periodontally affected tooth or root that predisposed the dog to the pathologic fracture. Retention of a periodontally diseased tooth or root in a fracture site inhibits fracture healing. If hemisection is chosen as the method of treatment, the retained root must be treated endodontically. In addition teeth that are fractured with pulpal exposure require endodontic therapy. Teeth that are not diseased but are located in the fracture site can generally be retained. Prognostic factors of teeth in the fracture site have been reported with fractures extending along the periodontal ligament to the apex having the poorest prognosis. In general it is probably best to retain teeth that significantly contribute to fracture stability as long as severe periodontal disease is not present and the fracture is acute. Basic principles of jaw fracture management include the following: (1) restoration of occlusion and anatomic reduction of the fracture, (2) neutralization of forces on the fracture line and stable fixation, (3) avoidance of soft tissue entrapment by the fixation technique, (4) avoidance of further dental trauma, (5) proper assessment of tissue viability, (6) removal of diseased teeth with the fracture site, (7) avoidance of excessive elevation of soft tissue from the surface of the bone and covering of exposed bone with soft tissue, and (8) rapid restoration of function. Several techniques for the management of mandibular and maxillary fractures have been described and include: (1) tape muzzles, (2) circumferential wiring, (3) interdental splints, (4) percutaneous skeletal fixation, (5) bone plating, and (6) partial mandibulectomy. Tape muzzles are an inexpensive, noninvasive technique of aligning and stabilizing jaw fractures. They can be used to temporarily stabilize jaw fractures prior to definitive repair. Tape muzzles can also be utilized as the primary repair technique in minimally displaced stable fractures especially fractures of the mandibular ramus or fractures occurring in young animals in which bone healing occurs rapidly. Interdental splints are an easy, noninvasive, versatile, and inexpensive technique for repairing jaw fractures. Prior to application of an interdental splint the teeth should be cleaned, polished, acid-etched, rinsed and dried. A self-mixing Bis Acryl-composite material can then be applied to the lingual surface of mandibular teeth or the labial aspect of maxillary teeth in the fabrication of interdental acrylic splints. Interdental splints are removed by sectioning the splint interdentally with a bur and gently removing the splint in segments using extraction forceps in a shearing motion to avoid fracturing teeth. Following splint removal the teeth are polished. Percutaneous skeletal fixation devices may be used to repair jaw fractures. This technique is particularly useful in fractures in which there is significant soft tissue trauma, in severely comminuted fractures and in fractures in which a significant boney defect is present. Bone plates provide rigid fixation and rapid return to function. However, bone plates can be technically challenging to place without damaging teeth. Significant soft tissue elevation is necessary for the placement of bone plates which may further compromise the blood supply of the fractured bone. It is also difficult to apply a bone plate to a fractured mandible or maxilla without further traumatizing tooth roots or neurovascular structures. It is also difficult to achieve normal postoperative occlusion using plates for jaw fracture repair because even slight errors in reduction of a fracture particularly in caudal fractures will result in a significant malocclusion with inability of the patient to close the mouth in some cases. Miniplates may be utilized in the repair of mandibular and maxillary fractures. The small size of these implants allows placement close to the alveolar border and the screws may be angled to avoid impringement on tooth roots. Partial mandibulectomy can be utilized in the management of mandibular fractures when extensive trauma or infection precludes reduction or adequate fixation. Partial mandibulectomy techniques should be limited to cases in which primary fracture repair is likely to fail or cases in which primary fracture repair has resulted in an inability to eat and drink. Maxillofacial fracture complications can be subdivided into the following categories. Complications in juvenile patients include interference with future growth potential resulting in facial deformities and damage to unerupted permanent teeth. Young patients with maxillofacial trauma should be treated conservatively. Factors that may complicate the treatment of maxillofacial fractures in geriatric patients include concurrent systemic diseases and severe periodontal disease with associated bone loss and an increased risk of pathologic fractures and neoplasia. Geriatric patients also have a higher incidence of postoperative complications such as delayed and nonunions. Several maxillofacial fracture complications may be related to implants. These potential complications include implant exposure, loosening of implants and migration and implant failure. Several factors can influence the normal healing process following maxillofacial trauma. These factors include the age of the patient, the amount of stability following fixation of the fracture site, bone loss at the fracture site, location of the fracture, integrity of the regional soft tissues, the blood supply at the fracture site, and foreign material in the fracture site. These factors have a significant impact on the potential development of healing complications including an increased incidence in the development of delayed union, non-union, and malunion. The major contributing factor to the development of delayed and nonunion is inadequate fracture stability. Additional factors that may contribute to the these complications include: vascular impairment, large fracture gaps, interposed soft tissues, infection, and inappropriate use of skeletal implants. Teeth in the line of the fracture may also delay or prevent healing particularly if the teeth in the fracture site are diseased or loose. Infectious complications that may be associated with maxillofacial trauma include: wound infections, osteomyelitis and bony sequestra. These complications are treated with thorough wound debridement and administration of broad spectrum antibiotics based on culture and sensitivity testing. Malocclusion and various dental pathological conditions may be complicating factors in the management of maxillofacial fractures. Failure to align fracture segments properly during fixation may result in significant malocclusions postoperatively. This may require removal of fixation devices, proper realignment and restabilization. When postoperative traumatic occlusion is limited to one or two pairs of teeth, selective extraction may be elected as an alternative treatment plan. Dental pathology that may be related to maxillofacial fracture complications include: periodontal, endodontic and iatrogenic conditions. Geriatric small breed dogs with severe periodontal disease may be predisposed to pathologic fractures through circumferential periodontal defects in the region of the mandibular first molars and deep periodontal pockets around the canine teeth. Management of these difficult cases includes extraction of periodontally diseased teeth placement of a cancellous bone graft combined with some type of fixation. Teeth in a fracture line can have a significant effect on fracture healing. The decision to extract or retain a tooth in a fracture line is based on several factors including: timing of fracture repair, the presence of concurrent dental disease, and location of the fracture line in relation to the root. In general, retention of healthy teeth can improve the operator's ability to achieve anatomic reduction and stabilization of the fracture site. Severely compromised teeth require extraction. Occasionally complications may occur following maxillofacial trauma because of extensive callus formation. Extensive callus formation in the region of the temporomandibular joint or between the zygomatic arch and the coronoid process of the mandible may result in limited or inability to open the mouth. Extensive callus formation may necessitate the performance of one or more surgical procedures including: condylectomy, surgical removal of the zygomatic arch and/or coronoidectomy. Frequent physical and radiographic evaluations of patients following maxillofacial trauma can help minimize serious postoperative complications and permit early detection of problems. Diligent postoperative care will help minimize postoperative pain and shorten the postoperative recovery period. References:
Management of Challenging Oral Cases Management of challenging oral cases include the management of osteomyelitis and bone sequestra, bilateral pathologic caudal mandibular fractures secondary to chronic periodontal disease, dentigerous cysts, dens-in-dente, base-narrow mandibular canine teeth, palatal defects, pharyngeal mucoceles, choanal atresia, inability to open or close the mouth, electrical injuries, non-healing oral lesions, and ophthalmic manifestations of dental diseases. Osteomyelitis and bone sequestra Osteomyelitis and bone sequestra occur infrequently in dogs and cats and may be a complication of advanced periodontal disease, extraction complications or maxillofacial fractures. Several cases of severe osteomyelitis with secondary necrosis of bone have occurred in Cocker Spaniels and less frequently in other breeds. These animals are usually presented for examination because of fetid breath, severe oral pain, facial swelling, reluctance or inability to eat and have severe purulent nasal discharge if the osteomyelitis or bone sequestra are located in the maxilla. Dental radiography is performed to assist in the diagnosis. All necrotic bone and teeth in necrotic bone must be removed and the surrounding bone must be curettaged to the level of healthy, bleeding bone. Intraoperative samples should be collected and submitted for bacterial culture and sensitivity testing. Samples of tissue should also be submitted for histopathologic examination to rule out the possibility of an underlying neoplasia. The surgical site should be liberally flushed with sterile saline and closed with a mucoperiosteal flap using 3-O PDS in a simple interrupted pattern. Bilateral Pathologic Caudal Mandibular Fractures Secondary to Chronic Periodontal Disease Bilateral pathologic caudal mandibular fractures can be an infrequent but severe complication of advanced periodontal disease. These pathologic fractures may occur in the region of the first mandibular molars and often occur following minimal bony stress. These types of fractures tend to occur most frequently in geriatric, small breed dogs and have been described as "orthopedic disasters." Various techniques for repair of these fractures have been utilized including tape muzzles, acrylic splints, percutaneous skeletal fixation devices, bone plates, pins and cerclage wires with variable success. A salvage procedure can be utilized in these cases when more traditional fixation techniques fail or are highly unlikely to have a successful outcome. All diseased teeth should be extracted and avascular ends of the exposed hemimandibles are removed with rongeurs resulting in 1-2 centimeters of bone loss bilaterally. The fracture sites are flushed and mucoperiosteal flaps are elevated and sutured over the exposed bone ends with 4-0 monofilament absorbable sutures in a simple interrupted pattern. A cheiloplasty is performed by removing the mandibular and maxillary lip margins from the level of the commissures of the lip to the distal aspect of the mandibular canine extraction sites. The labial mucosa is closed bilaterally in a simple interrupted pattern with 4-0 monofilament absorbable suture pattern. The skin is closed with 4-0 nylon in a simple interrupted pattern. Postoperatively a soft gruel diet is recommended for 2 weeks after which the diet can slowly be changed to soft canned dog food. Dentigerous Cysts Dentigerous cysts occur infrequently in dogs, however, the diagnosis of dentigerous cysts should be a primary consideration in young dogs presenting with fluid filled oral swellings. Additionally, the possibility of an iatrogenic dentigerous cyst must be considered in those dogs in which a deciduous tooth was extracted or a traumatic episode had occurred in a puppy and subsequently the permanent tooth fails to erupt. Definitive diagnosis of a dentigerous cyst is based on history, physical examination, radiography, and histopathologic examination. Dentigerous cysts arise from the cellular components of the developing dental follicle. The cyst contains one or more embedded teeth and usually surrounds the coronal aspect of the tooth. As the tooth bud continues to develop but fails to erupt, the cyst becomes filled with fluid. Fluid pressure within the cyst results in a smooth-bordered radiolucent cavity typically adjacent to the cementoenamel junction as viewed radiographically. The treatment of a dentigerous cyst usually involves surgical extraction of the affected tooth and thorough removal of the entire epithelial lining of the cyst wall which is submitted for histopathologic examination. Complete excision of the tooth and the cystic epithelium is curative. Dens-in-Dente Dens-in-dente is a rare developmental disturbance in tooth formation which results in an invagination of the epithelium associated with coronal development into the area of the tooth which was destined to become the pulp space. Following calcification of the tooth there is an invagination of enamel and dentin into the pulp space and a distortion of this space and the root contour to accommodate this invagination. This results in secondary endodontic disease and often convergence of roots in multirooted teeth which may be evident radiographically as large pulp canals and periapical lysis. This condition is often frequently bilaterally symmetrical and appears to most frequently affect the lower 1st molars in dogs. Treatment includes either exodontia or endodontic therapy. Base-Narrow Mandibular Canine Teeth in Dogs Base-narrow mandibular canine teeth in dogs often results in traumatic occlusion of the lower canine teeth with the soft tissues of the hard palate. This malocclusion can result from an extreme retrognathic mandible (more caudal than normal location of the mandible), brachygnathic mandible, excessive anisognathism (uneven jaw size), or retained deciduous canines that have directed the lower canines into a more lingual than normal base narrow position. Since all of these conditions are considered to be genetically linked breeding of these animals is not recommended. Some cases of base-narrow mandibular canine teeth may be corrected by encouraging dogs to play and chew on a large ball positioned in the front of the mouth. Malocclusions that are not successfully treated utilizing this simple technique may be corrected with direct bite planes. Bilateral inclined planes are constructed between the maxillary canines and third incisors so that the tip of the mandibular canine teeth hit the inclined planes in such a way as to redirect the mandibular canine teeth into a more normal location thereby eliminating the traumatic malocclusion. The time required for tooth movement utilizing this technique is usually between 2 and 6 weeks. Palatal Defects Animals with congenital palatal defects are usually presented for signs related to incomplete separation of the oral and nasal cavity including: drainage of milk from the nares during or after nursing; gagging, coughing, or sneezing while eating; and respiratory infection including rhinitis and/or aspiration pneumonia. Once the decision is made that surgical intervention is an appropriate treatment option, the appropriate surgical procedure is selected based on the location and size of the palatal defect. Timing of the surgical repair is also critical and if possible the repair should be delayed until the patient is approximately 4 months old. The best chance of success is with the first surgical procedure and the larger the animal is at the time of surgery, the more tissue available for repair of the defect. Two basic techniques have been described for the repair of congenital hard palatal defects including the medially repositioned double flap technique and the overlapping flap technique. The medially repositioned double flap technique involves creation of bilateral releasing incisions approximately 2mm from the upper dental arches. The epithelial margins are removed from along both edges of the defect. The mucoperiosteum is undermined bilaterally on both sides of the defect carefully avoiding laceration of the palatine arteries as they exit the palatine foramina palatal to the upper fourth premolars. The flaps are repositioned medially and sutured over the defect. The overlapping-flap technique is generally preferred for repair of midline hard palatal defects because this technique is associated with less tension on the suture line, the suture line is not located directly over the defect and the area of opposing connective tissue is larger, which results in a stronger scar. The overlapping-flap technique is initiated by making an incision the length of the palatal defect on the patient's right side 2-3mm palatal to the maxillary dental arch. Perpendicular incisions are made at the rostral and caudal ends of this incision extending to the cleft. The caudal incision should be preplanned so that it lies over the hard palate and not through the soft palate to prevent creation of an oronasal fistula. A blunt tipped curved Freer periosteal elevator is used to carefully elevate the mucoperiosteal layer carefully avoiding the palatine artery as it exits the palatine foramen approximately 10mm palatal to the maxillary fourth premolar. When elevating in the area overlying the palatine fissure, a partial thickness elevation is recommended so that the deepest layer remains with the bone thereby preventing exposure of the palatine fissure and formation of an iatrogenic oronasal fistula. Care must also be taken when elevating this flap not to penetrate the medial edge of the cleft where the oral mucosa is contiguous with the nasal mucosa. A second incision is made in the mucoperiosteum on the left side of the patient's cleft along the entire length of the defect and the mucoperiosteum is elevated approximately 8-10 mm along the entire length of the defect. The mucoperiosteal flap from the right side of the defect is hinged or folded over the defect and positioned between the hard palate and the mucoperiosteal flap on the left side of the cleft. The hinged flap should cover the defect and overlap beneath the opposite mucoperiosteal flap approximately 6mm without tension. In very wide defects, a secondary releasing incision 2-3 mm palatal to the left dental arch may be required to permit adequate overlap without tension. The hinged flap is sutured in place using multiple interrupted horizontal mattress sutures using 3-0 monofilament absorbable suture material. These sutures should be preplaced from caudal to rostral and tagged temporarily with hemostats. Following placement of all sutures the sutures are tied from caudal to rostral. The defect created by the raised hinged flap is allowed to heal by second intention and usually takes 3-4 weeks to completely granulate and reepithialize. Midline soft palatal defects commonly accompany hard palatal defects. Soft palatal defects may occur when hard palatal defects are absent, however, they are more frequently identified when hard palatal defects are present. Midline clefts of the soft palate are most commonly seen and are located medial to the palatine muscles. Unilateral or bilateral congenital defects of the soft palate occur less commonly and are located lateral to the palatine muscle. Midline clefts of the soft palate can often be corrected utilizing a double layer appositional technique as long as no tension is created during closure of the defect. Animals with hypoplastic soft palates with bilateral soft palatal clefts have significantly shortened soft palates. Oropharyngeal examination in these patients typically reveals a near absence of the soft palate with a small uvula-like projection that extends from the mid-caudal aspect of the hard palate. Various recommendations have been made concerning the most appropriate treatment for hypoplasia or congenital absence of the soft palate ranging from surgical correction to euthanasia. Normal compensatory mechanisms, proper dietary management, combined with surgery if necessary may permit dogs with congenitally shortened soft palates to lead a relatively normal life. Prior to surgical repair of acquired palatal defects it is important to carefully decide what therapeutic plan is likely to be most successful in a particular type of defect. Therapeutic decision making in these cases is usually based on the cause, the size and location of the defect and whether or not there has been any prior surgical intervention. The best chance of success for repair of palatal defects is with the first surgical procedure, therefore, appropriate treatment planning is crucial. Various single-layer surgical techniques can be used to repair acquired palatal defects, including buccal flaps, rotation flaps, advancement flaps, tongue flaps, split palatal U-flaps, and island palatal flaps. In general, the technique that provides the largest flap with no tension and an adequate blood supply is recommended. Pharyngeal Mucoceles Dogs with pharyngeal mucoceles typically are presented because of difficulty breathing or swallowing. Confirmation of pharyngeal mucoceles is made on oral examination and aspiration of a clear or blood-tinged, ropey fluid that is consistent with saliva. The animal should be preoxygenated if possible prior to induction and entubated rapidly to prevent anoxia secondary to obstruction of the upper airway by the pharyngeal mucocele. Pharyngeal mucoceles are treated by marsupialization of the mucoceles and removal of the ipsilateral mandibular and sublingual salivary glands. Choanal Atresia Bilateral choanal atresia has been reported in the dog and has a similar presentation to cats with nasopharyngeal stenosis. Surgical excision of the obstruction through a ventral rhinotomy has been recommended. However, obstruction secondary to scar tissue formation is likely and a permanent tracheostomy may be necessary to relieve clinical signs of severe upper airway obstruction. Inability to Open the Mouth Several pathologic conditions in the dog can cause a dog to be unable to open the mouth. These conditions include masticatory muscle myositis, adhesion of the zygomatic arch to the ramus of the mandible following trauma, neoplasia in the region of the temporomandibular joint and craniomandibular osteopathy. Inability to Close the Mouth Several pathologic conditions in the dog can cause a dog to be unable to close the mouth. These conditions include idiopathic trigeminal neuropathy also known as canine dropped jaw syndrome and displacement of the coronoid process lateral to the rostral part of the zygomatic arch in dogs with dysplastic temporomandibular joints. Displaced teeth maloccluding with the opposite dental arch may prevent proper closing of the mouth. Foreign bodies wedged over the teeth may also prevent proper closing of the mouth. Electrical Injuries Chewing on electrical cords is the most common cause of electrical injuries in dogs and cats. Electrical burns occur primarily on the lips, gingiva, palate and tongue. Initially affected areas may appear charred, pale gray or tan. Edema occurs one to 2 days following the injury. The full extent of the injuries may not be apparent for 2 to 3 weeks. Treatment of patients with electrical injuries includes assessment for pulmonary edema and treatment with diuretics, aminophylline and morphine. Repair of damaged tissues should be delayed until the full extent of the injuries is firmly established. Minor injuries often heal by second intention. Oronasal fistulas should be repaired with appropriate mucoperiosteal flaps. Necrotic bone must be debrided and teeth affected by electrical injuries should be appropriately treated. Non-Healing Oral Lesions When middle aged to older animals are presented because of difficulty eating the oral cavity should be carefully examined for oral lesions. When a non-healing oral lesion is found it should be examined closely. A fine needle aspirate should be taken for cytologic evaluations. In addition tissue samples should be taken for impression smears and histopathologic examinations. The possibility of a neoplastic process must be considered in these cases and treated appropriately. Ophthalmic Manifestations of Dental Diseases There are several ophthalmic manifestations of dental disease including periorbital and orbital emergencies and are most frequently associated with periodontal and endodontic disease of the maxillary 4th premolar, 1st molar, and 2nd molar. Periorbital signs are usually depicted as acute painful periorbital swelling. Orbital signs are usually depicted as exophthalmus, elicitation of pain upon opening the mouth, and corneal ulcers. Conformation of a primary dental problem is achieved with a thorough oral examination and dental radiography. Severe periodontal disease with deep periodontal pockets, fractured teeth with pulpal exposure and endodontically diseased teeth without pulpal exposure may be the cause of the underlying ophthalmic signs. Treatment includes extraction of diseased teeth. References:
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