Contributors: Jan Bellows, David Crossley, Mark Thompson

 Species: Feline   |   Classification: Techniques

Introduction Requirements Preparation Procedure Aftercare Outcomes Further Reading

Introduction

Uses

  • Mobile teeth.
  • Periodontal disease Periodontal disease.
  • Supernumerary teeth: if affecting occlusion or crowding other teeth.
  • Persistent deciduous teeth Retained temporary teeth (Persistent primary teeth).
  • Advanced caries.
  • Fractured teeth Dental fracture: if beyond repair, eg long axis root fractures, root fractures in the middle third, teeth with crown fractures when no endodontic treatment is authorized.
  • Teeth on fracture line of fractured mandible or maxilla.
    Skull smaller and more fragile in cat than in dog.

Alternative Techniques

  • Endodontic techniques.
  • Restorative techniques.

Decision Taking

Criteria for choosing test

  • Ensure client understands that general anesthesia is necessary.

Requirements

Materials Required

Minimum equipment

  • Scalpel blade No. 11  Surgical instruments: scalpel blades and handle.
  • Molt p9 periosteal elevator .
  • Root tip pick.
  • Svenska luxators  Endodontics Instrument: Svenska luxator : 3 mm straight, 3 mm curved.
  • Lindo-Levien elevators: LLL, LLM, LLS.
  • Needle holder  Endodontics instrument: needle holder - Mayo-Hegar .
  • Fine-toothed dissecting forceps.
  • Straight scissors 5 inch  Endodontics instrument: scissors - straight .
    Must be sharp.
  • Dental elevator: a selection of sizes to match tooth root size and diameter.
  • Cutting burrs  Endodontics instrument: tungsten carbide bur - 124  Endodontics instrument: tungsten carbide bur - 138 : 701, 702, 330, round 2, 3, 4 and 5
  • Bone file Endodontics instrument: bone file .
  • Drapes, clips, swabs.

Minimum consumables

  • Suture material: monocryl 1.5 metric rapidly absorbable suture with swaged on cutting needle.

Preparation

Pre-medication

  • Opioid .

Restraint

  • Mouth prop.
    Avoid using sprung mouth gags in cats as can cause serious muscle damage.

Procedure

Approach

Step 1 - Single-rooted teeth

  • Cut epithelial attachment at bottom of sulcus with No. 11 blade at 25° to long axis of root.
  • Select an elevator or luxator with correct blade.
    Select blade with circumference one third the size of a target root.
  • Introduce the elevator/luxator in an apical direction between alveolar bone and root surface .
  • Rotate luxator blade circumferentially while maintaining apical pressure .
  • Stop from time-to-time to allow the hydraulic pressure of hemorrhage from periodontal ligament to assist expulsion of root from alveolus.
  • Continue working luxator against all surfaces of root until loose .
  • Extract loose root .
  • Debride alveolus, removing bone spikes .
  • Radiograph to ensure complete removal.
  • Suture gingiva.

Step 2 - Multi-rooted teeth

  • Create one or more single roots for extraction.
  • Break down epithelial attachment (see single-rooted tooth - earlier).
  • Lift full-thickness mucous membrane and gingiva from bone using Molt elevator .
  • If necessary incise gingiva at caudal and mesial margins diverging away from root axis.
  • Remove semi-circle of crestal bone, using 701 cross-cut taper fissure burr, to identify furcation angle.
  • Split tooth in two halves cutting from furcation coronally.
  • Apply elevator into cut channel and gently rotate to push two roots apart.
  • Hold pressure for 10 seconds then turn blade around and repeat procedure.
  • Combine with longitudinal elevation of tooth root.
  • Keep applying pressure until one or both roots becomes loose.
  • Remove loose root.
  • Elevate remaining root normally.
  • Debride, filing off bone spikes.
  • Suture gingiva.
  • Radiograph to ensure complete removal.

Step 3 - Upper canine

  • Sever epithelial attachment (see single-rooted teeth).
  • Locate end of root by digital palpation following lateral canine eminence.
    Locate 2 mm rostral to rostral margin of root to avoid post-extraction suturing over a void.
  • Extend incision forward to caudal margin of corner incisor and caudal to mesial root of lower premolar 2.
  • Use Molt elevator to lift full thickness mucoperiosteal flap from leading margin at mesial angle of canine backwards to expose lateral canine eminence.
  • Use a 701 cross-cut fissure burr or similar high speed, water cooled handpiece.
  • Insert a luxator blade into the mesial channel down the long axis direction and rotate in a lateral direction.
  • Repeat until periodontal ligament begins to loosen.
  • Apply the blade to caudal channel in a similar direction and rotate.
  • Repeat from side-to-side until root loosens and can be gently lifted from the socket with forceps.
  • Gently irrigate the socket with saline 0.05% chlorhexidine gluconate.
    Blood or fluid from ipsilateral nostril indicates a fistula (see complications).
  • Suture flap, using interrupted sutures. Start at leading edge of flap nearest caudal margin of upper incisor.
    ESSENTIAL that sutures are not under tension otherwise dehiscence will occur.

Step 4 - Lower canine

  • More difficult than extracting upper canine tooth: long axis of tooth is buccolingual rather than dorsoventral; apex lies at caudal end of mandibular symphysis .
  • Sever epithelial attachments as for single-rooted teeth .
  • Incise oral mucous membranes on lingual aspect along the long axis of tooth from mesial margin .
  • Cut channel round outline of root on lingual aspect to mid root depth or remove lingual bone plate with bone chisel.
  • Apply luxator blade to caudal channel along long axis of root - rotate blade while applying pressure apically to rotate root out of alveolus.
  • Repeat process in reverse with blade in mesial channel.
  • Irrigate and suture (see upper canine extraction).

Step 5 - Deciduous teeth

  • Indications: crowding. Most common is lingually displaced mandibular canines with the tips of the lower canines occluding into the hard palate.
  • All deciduous teeth are rostral to their permanent counterparts with exception of lower canines which are buccal to permanents.
  • Extraction follows same principle as permanent teeth, but deciduous teeth more fragile and prone to fracture.
    Excessive luxation may damage permanent tooth if it is undergoing amelogenesis at this time - important to know location of permanent tooth bud.
  • Pre- and post-extraction radiography is very useful.

Aftercare

Immediate

Analgesia

  • Opioid administered pre-operatively or intra-operatively.

Antimicrobial therapy

  • Antibiotics: good bone penetration; gram-negative anaerobic spectrum Clindamycin.

Potential complications

Oro-nasal fistula (ONF)

  • At any location most commonly upper canines and caudally to them, where bone plates thinnest, ie medial to upper canine and upper premolar 4.

Flap dehiscence

  • Requires complex flap surgery. Correct attention at the time of extraction can limit the need for complex flap surgery later. Debride socket gently with 0.05% chlorhexidine gluconate and suture the tissues closed without tension. Treat with suitable antibiotics. Review after 4-6 weeks to identify the need for flap surgery.
  • Most commonly caused by tension on sutures or active infection at site.
    Expect 20% contraction of soft tissues during healing.
  • Many oro-nasal fistulae stay open due to pressure differential between nasal and oral cavity.
  • After 6 weeks, if ONF present, closure is indicated Oronasal fistula repair otherwise chronic rhinitis will occur (although may not be clinically apparent).

Hemorrhage

  • Most sockets stop bleeding quickly post-extraction with little need for attention beyond gentle pressure.
  • Packing socket with polylactic acid granules (expensive) or bone graft (cheap) may help.
  • Hemostatic gauze may help but has to be removed after a short period.
    Beware of clotting factor defects. Pre-test clotting factors to assess suitability for surgery or bleeding time .
  • Hospitalize overnight if necessary.

Root fracture

  • Common with poor technique. Carnivore teeth taper towards the apex. Over-robust and impatient elevation will fracture the root.
  • A fractured fragment containing necrotic pulp or in an infected periodontal pocket will cause bone lysis and must be removed:
    Either Use a root tip pick or fine blade luxator to loosen and remove root tip.
    Or Burr away part of the bone plate to remove the root tip.

Mandibular body fracture

  • Beware of extensive bone loss predisposing to fracture.
    Pre-operative radiography may be helpful in assessing risk.
  • Support body of mandible with the palm of the hand during tooth elevation.

Mistaken removal of permanent tooth

  • Use radiography to differentiate temporary from permanent tooth - temporary teeth may have a less distinct root morphology.
    Do not extract tooth unless sure it is temporary - seek expert advice if necessary.

Outcomes

Complications

  • See under Aftercare/Complications.

Reasons for Treatment Failure

  • See earlier.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Wiggs R B, Lobprise H, Mitchell P Q (1998) Oral and periodontal tissue. Maintenance, augmentation, rejuvenation and regeneration. Vet Clin North Am Small Anim Pract 28 (5), 1165-1188 PubMed.
  • Smith M M (1996) Lingual approach for surgical extraction of the mandibular canine tooth in dogs and cats. JAAHA 32 (4), 359-364 PubMed.
  • DuPont G (1995) Crown amputation with intentional root retention for advanced feline resorptive lesions - a clinical study. J Vet Dent 12 (1), 9-13 PubMed.
  • Scheels J L, Howard P E (1993) Principles of dental extraction. Semin Vet Med Surg Small Anim (3), 146-154 PubMed.

Other sources of information

  • Wiggs R B, Lobprise H B & Lipincott-Raven (1997) Veterinary Dentistry, Principles and Practice.