& Management / Disease
Investigation & Management / Techniques:
||Root filling (including
pulpectomy, i.e. total removal of pulp tissues from the tooth). (B452.8.w8)
NOTE: Although the procedure is described
below as accurately as possible, this is NOT a substitute for learning the
procedure by watching and assisting a veterinarian who is already
experienced in the technique.
- Anaesthetise the bear. See: Treatment and Care
- Intubate and place on inhalational anaesthesia .
- Place a wooden block or other suitable instrument to keep the mouth
- Place a rubber dam over the tooth.
- This helps to maintain asepsis.
- The dam also reduces debris and blood reaching the throat and
being aspirated into the lungs during recovery from anaesthesia. (P1.1979.w4)
Clean out the pulp cavity
- Clean out the whole pulp
- Enlarge access to the canals using a round bur. (J432.15.w1)
- If most of a canine tooth is still intact, working from the tip
will not give a straight line access to the apex.
- An access cavity is made on the mesial surface of the tooth
using a round or pear-shaped burr to give straight line
- Confirm the working length of the root canal e.g. by inserting a
radiopaque instrument into the canal and taking a radiograph. (J432.15.w1)
- Debride the root canal with root canal reamers and K files of
increasing size. (J432.15.w1)
- Mark the working length onto each file using a rubber endodontic
file stop. (J432.15.w1)
- Start with smaller files and work up to larger files. (B10.34.w41)
- Use a debridement paste with the files. (B10.34.w41)
- All debris must be removed; keep cleaning until the material
coming out appears clean and vital. (B10.34.w41)
- Measure advancement to the root apex using radiographs. (B10.34.w41)
- Do not perforate the proximal tip of the root. (B10.34.w41)
- Irrigate the pulp chamber with 3% hydrogen peroxide solution,
alternated with 2.5% or 3% sodium hydroxide solution. (P64.26.w6,
- Dry the canal:
- First irrigate the pulp chamber with 70% ethyl alcohol. (P64.26.w6,
- Remove any remaining moisture using sterile pipe cleaners,
cotton-tipped swabs and paper points. (B10.34.w41,
- Irrigate the canal with compressed air to finish the drying. (B10.34.w41)
Pack the canal
- Usually, gutta-percha points plus a root canal sealer are used to
pack the canal. (B470.16.w16)
- Fill with sealed-coated gutta-percha points using a lateral
step-back condensation technique. (J432.15.w1)
- To fill the large canine teeth of a bear, the leading gutta-percha point can be thickened and lengthened
by adding two 30 mm points, heating, and rolling the points
- Seal with zinc oxide-eugenol or bismuth (II) oxide-silver-methenamine-resin.
- Mix zinc oxide powder: 2-3 g zinc oxide powder to one drop
liquid eugenol and one drop foracresol. This produces a dry,
malleable putty which can be used to fill the canal. (P64.26.w6)
- Use a dental filler or root-canal sealant. (B10.34.w41)
- To reach the root apex it may be necessary to use a flexible
needle or plastic catheter. (B10.34.w41)
- 1) make a retentive shallow undercut in the dentine, line the
cavity with zinc phosphate cement, condense silver amalgam into
the preparation, shape and polish. (J432.15.w1)
- 2) etch the enamel and dentin with 30% phosphoric acid, restore
using a light curing compound, a dentine primer and a bonding
- 3) Re-drill the cavity to a depth of 3 mm, making sure there is an
- Mix a dental restorative resin as indicated by the manufacturer and
use this to pack the cavity.
- Apply firm finger pressure to the restorative for 30 seconds, then
allow to air dry.
|Appropriate Use (?)
- Treatment of tooth fractures which have exposed the pulp tissue. (B10.34.w41)
- Not including vertical fractures. (V.w6)
- Treatment of teeth with severe attrition exposing the pulp.
- Treatment of broken canines with a horizontal fracture of the crown
of the tooth, without fracture extension subgingivally or affecting
the root, a closed root apex, and no evidence of periodontal disease.
- Note: bears maintain root-fillings well if the fillings are properly
- The principles of root fillings are:
- Complete access to the contents of the root canal;
- Debridement of the canal, removing all tissue (e.g. necrotic
pulp, vital pulp, pus).
- Preparation of the canal, removing infected dentine, smoothing
irregularities and widening the canal to a proper diameter for
- Disinfection, to reduce to a minimum the presence of
- Obturation - hermetic sealing of the canal with a permanent
filling material, so that no microorganisms can penetrate the
canal and multiply in a dead space.
- The filling material (e.g. gutta-percha points) should reach all the
way to the apex of the tooth root. (J432.15.w1)
|Complications/ Limitations / Risk
- Care must be taken not to perforate the proximal tip of the root. (B10.34.w41)
- In some cases post-operative radiographs indicate that the apical area is not
reached with the gutta-percha points. (J432.15.w1)
- This procedure is not suitable for teeth where the fracture extends
subgingivally (under the gum) or affects the root, the root apex is open, or if there
is evidence of periodontal disease. (J60.12.w1)
- If there is a vertical crack affecting the pulp cavity and extending
below gumline, the tooth needs to be removed, not filled. (V.w6)
|Equipment / Chemicals required and Suppliers
|Expertise level / Ease of Use
- This procedure should be carried out by personnel with experience
and training in dental surgery in animals. (V.w6)
- The costs of this procedure include the costs of the personnel
required (minimum one suitably qualified person to carry out the
dental work and one to monitor the anaesthetic), and costs of
- Appropriate dental equipment to carry out this procedure properly on
bears may be expensive.
|Legal and Ethical Considerations
- In some countries there may be
legislation restricting the use of this type of technique to licensed veterinarians. For
example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides,
subject to a number of exceptions, that only registered members of the Royal College of
Veterinary Surgeons may practice veterinary surgery." (see: LCofC1
- RCVS Guide to Professional Conduct 2000 - Treatment of
Animals by Non-Veterinary Surgeons).).
||Debra Bourne MA VetMB PhD
||Suzanne I. Boardman BVMS