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AVA lecture notes 2005 - Extraction.doc


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AVA lecture notes 2005 - Extraction.doc

  1. 1. DENTAL EXTRACTIONSDr David E. ClarkeBVSc., Diplomate AVDC, Fellow AVD,MACVSc, MRCVSRegistered Specialist, Veterinary DentistryDental Care for PetsPO Box 5015Hallam, Vic, 3803Phone: (03) 9702 4432Fax: (03) 9703 indications for extractions:The decision to extract a tooth should be a co-operative one between owner andVeterinarian, but ultimately guided by the Veterinarian.According to the disease process, condition of the tooth, technique and instrumentsemployed, extractions can be quick and simple, or very time consuming and frustrating.Possible reasons to extract a tooth include: 1. Retained deciduous teeth 2. Interceptive orthodontics 3. Severe periodontal disease 4. Highly mobile teeth 5. Endodontic disease (fractured teeth) 6. Impacted teeth 7. Oral fractures, tumours and cysts 8. Severe disease or injury to the crown, neck or root of the tooth 9. Malocclusions 10. Supernumerary teethEssentials for good extraction technique 1. Accessibility to the site a. Proper positioning of the animal b. Appropriate mouth gag or prop 2. Good visibility a. Proper and precise lighting source b. Cheek and tongue retractors c. Good quality dental mirror 3. Knowledge of extraction technique 4. Knowledge of tooth root attachment and the anatomy of crown and root
  2. 2. Figure 1. Anatomy of the tooth and supporting structures 5. Quality extraction instruments and a good knowledge of their appropriate use 6. Positioning for the practitioner a. Comfortable b. Allows for good visibility c. Provides the needed arm, hand and instrument rests and support d. Affords for a proper fulcrum for hand and instruments when requiredProper grip of the InstrumentHold the instrument properly for the best leverage and control. The hand should wraparound the handle with the thumb in the thumb clutch groove, the butt of the handle in thepalm, and the forefinger held tight against the working tip for control.Figure 2. The correct technique of holding a dental elevatorDental formulae and root numbersDogs: I33 C11 P44 M23 Cats: I33 C11 P32 M11 Dog-number of tooth roots Cat-number of tooth rootsTooth Maxilla Mandible Maxilla MandibleIncisors 1 1 1 1Canine 1 1 1 1Premolar 1 1 or 2 1 or 2 No upper No lowerPremolar 2 2 2 1 No lowerPremolar 3 2 2 2 2Premolar 4 3 2 3 2Molar 1 3 2 3 (very small) 2Molar 2 3 2 No upper No lowerMolar 3 No upper 2 No upper No lowerTable 1. The number of roots in the maxillary and mandibular teeth in the dog and cat
  3. 3. Extraction techniqueA systematic approach is necessary for ease of procedure and reliable results. The followingis the basis for a dependable extraction plan: 1. Disinfect the oral cavity with a 0.2% oral chlorhexidine solution. 2. Examine the tooth physically for signs of disease or injury, such as periodontal disease, fractures, exposure of the pulp chamber, resorptive lesions, cavities, tooth mobility, proximity to major structures and organs, condition of the alveolar bone, oronasal fistulas, oroantral fistulas, tooth discolouration etc. 3. Pre-extraction radiographs can aid in the determination of root ankylosis, degree of tooth fragility, internal resorption, cervical line lesions, root caries and dilaceration of roots. 4. Evaluate each tooth and the radiographic findings. Some teeth will be found to be so mobile that they can be easily removed at this point with simple extraction forceps. 5. Pre-extraction local analgesia injection by regional block can be performed (to be covered in future newsletter). 6. Otherwise, sever the gingival epithelial attachment. This can be done with many instruments, but the following have been found to be effective: a. Scalpel blade b. Edge of a periosteal elevator c. The sharp tip of a root tip pick d. Blade of a winged elevatorFigure 2 Placement of a scalpel blade into the gingival sulcus to sever the epithelial attachment 7. Create a gingival flap for good visualisation when needed. An envelope flap may be sufficient, but in some cases a releasing flap may be necessary. a. Envelope flap – this can be accomplished by severing the gingival epithelial attachment and then working a periosteal elevator between the gingiva and the alveolar bone on the lateral and lingual surfaces of the tooth. b. Releasing flap – sever the gingival epithelial attachment and make two releasing incisions, one at each of the interproximal areas of the lateral gingival surface. The flap is then reflected using a #9 Molt periosteal elevator.
  4. 4. Figure 3 Position of releasing incisions (dashed lines) of gingival flap for extraction of the upper 4th pre-molar toothFigure 4. Position of releasing incisions (dashed lines) of gingival flap for extraction of the upper canine tooth8. Removal of the buccal alveolar bone plate may be necessary. a. For those without dental units - a bone chisel, osteotome with a small mallet, and/or bone rongeurs can be used to lift the buccal bone plate away from the tooth. In addition, periosteal and bone elevators can be used for this purpose. b. For those with dental units - round, pear or tapered burs on a high-speed handpiece can make fast work of the bone plate. The entire buccal bone plate section can be removed by just burring it away, or grooves on either side of the root can be cut and a periosteal elevator used to elevate the bone flap. On the canine teeth, creating a groove at the mesial and distal aspects of the tooth to provide space for elevator access can be useful on occasion.9. Section multi-rooted teeth (except those loose enough for simple forceps extraction) into their individual root segments. Extract only single rooted tooth sections, and it will make extractions much easier. a. For those without dental units - the sectioning may lead to problems of fractured or broken teeth. Molar cutters may either section the tooth nicely or fracture it into multiple pieces and break the roots. The use of hardened hack saw blades or even gigli wire could sometimes cut teeth with little work. The hacksaw can cut with time through the crown down through the tooth. However, gigli wire typically works better being passed under the tooth through the furcation between the roots and then cutting the tooth in half from the bottom side up. b. For those with dental units - sectioning can be done with a high-speed handpiece using a diamond or carbide steel crosscut fissure bur. It is best to visualise the furcation and section from the furcation coronally.
  5. 5. Figure 5. Using a high-speed bur in the furcation to section the upper 4th pre-molar tooth into individual distal and mesial roots.10. Sever or fatigue the periodontal ligament into releasing the tooth or root section. This can be done by placing the elevator into the space between the tooth and the alveolar bone, occupied by the periodontal ligament. Press the elevator along the tooth apically, using a slow twisting action on the winged elevator. Wriggle the elevator back and forth in a light rotating motion as you press down into the ligament space, until you gain depth. Work circumferentially around the tooth, until it begins to elevate out of the socket, or becomes loose so that it can be easily removed with a pair of extraction forceps.Figure 6. Placing the elevator parallel to the tooth root into the periodontal ligament spaceFigure 7. Stressing the periodontal ligament by placement and gentle rotation of the elevator between the two root segments11. For harder extractions you may wish to attempt to fatigue the ligament. To accomplish this, twist the elevator until there is mild tension between the tooth, alveolar bone and the elevator. The tension should be held for 10-30 seconds at a time, then move to another location on the tooth and repeat the process. Care should be taken with extraction of the maxillary canine teeth. The elevator or the root tip may perforate the alveolar bone and enter the nasal passage and contribute to the chances of oronasal fistula (ONF) formation. However, periodontal disease on the palatal or lingual side of the tooth may have previously caused an ONF and the tooth is hiding it. Therefore, always use a periodontal probe on the upper canine teeth to check for deep palatal pockets before initiating the extraction. To reduce the chances of ONFs use the elevator gently between the tooth and the alveolar bone on the nasal side. Additionally, always rotate the crown tip laterally rather than palatally during extraction to reduce the chance of the root apex being forced into the nasal passage. Once the tooth root is loose it may be grasped with forceps and removed.
  6. 6. Figure 8. A pair of extraction forceps are used to grasp the tooth root. A gentle rotation while pushing into the socket will aid in extraction. 12. When necessary root sections can be pulverised using the high-speed handpiece with a round or pear bur. Adequate water irrigation during this process is necessary to prevent bone necrosis from excessive generation of heat. Pulverisation may be necessary with ankylosed or fragile teeth, such as feline teeth with resorptive lesions, but should only be done with excellent visualisation and when radiographic support is available. 13. If granulation tissue or debris is present, curettage and debridement of the wound after extraction with a bone or periodontal curette, or surgical or periosteal elevator is indicated. 14. If bony spicules or irregular alveolar bone is present, osteoplasty should be performed. a. For those without dental units - this can usually be accomplished with rongeurs and bone files. b. For those with dental units - this can be quickly accomplished with a high- speed handpiece and round bur with adequate water spray to prevent thermal injury to the bone. 15. Post extraction radiology is indicated in all complicated extractions to assure removal of all root fragments, as well as to assess the condition of the adjacent teeth and bone for cracks or fractures and provide medical documentation. 16. Placement of osseous promotive products (Consil, TCP/doxy) that enhance bone growth into the empty socket can be of benefit to maintain the alveolar ridge. This is especially true in lower jaw extractions of the incisor, canine and carnassial tooth extractions, in order to help maintain the alveolar ridge and mandibular symphysis strength. 17. Close with a sliding flap and absorbable 3-0 or 4-0 suture material. Figure 9. After extraction and packing, the gingiva is sutured with 4/0 absorbable simple interrupted sutures. 18. Home care medications and instructions
  7. 7. a. Home care instructions – soft food 4 days, call the clinic if excessive bleeding, pain, or problemb. Dispensing of antibiotics (such as clindamycin).c. Dispensing of pain relief medications (such as carprofen).d. Dispensing of Maxiguard oral gele. Recheck animal in 14-21 days.