Advanced Veterinary Dental Techniques (Vital Pulp Therapy) Flashcards
What is the aim of Vital Pulp Therapy (VPT)?
The aim of this treatment is to keep a living, healthy pulp alive. It involves
removing only part of the pulp [partial pulpectomy] (rather than root canal
therapy which removes all of the pulp) and you will also see this referred to as a
pulpotomy procedure.
When is Vital Pulp Therapy performed?
It is only performed in two distinct situations-to preserve
the pulp of a freshly fractured crown, IF it is seen within 48 hours, OR after
elective crown shortening and VPT for certain malocclusion cases.
For crown fractures exposing the pulp what is the success rate based on how soon VPT is performed?
In 2001,
Clarke found that if treated within 48 hours of the injury, the success rate was
88%, but only 42% if the tooth was treated after 7 days, and only 24 % if treated
within 3 weeks. Thus we have another veterinary dental emergency!
If there is a
complicated crown fracture, and the client knows when it happened, if they can
reach a veterinary dentist within how many hours will VPT still be possible (rather than full RCT)?
48hrs
When is VPT vitally important?
In immature teeth when the apex has not fully formed, as full root canal therapy would not be possible. Instead, the tooth
would need to be treated by apexification to artificially close the apex.
Furthermore, a young, immature tooth is very weak as the dentinal walls are
very thin. If the pulp remains vital, further dentine can be laid down as the tooth
matures, thus strengthening it.
How must VPT be carried out?
VPT must be carried out in as sterile a manner as possible- handpieces,
instruments, materials and gloves should all be sterile.
What are the steps in VPT?
- Remove the inflamed coronal pulp with a sterile diamond burr with sterile coolant.
- Control hemorrhage with sterile saline soaked paper points.
- Once the pulp has stopped bleeding a sterile dressing is placed. (material of choice is
called MTA (mineral trioxide aggregate). - An intermediate liner layer of glass ionomer is placed.
- composite
restoration, to seal the crown. - Follow up radiographs should show a healthy periapical area, continued root
formation and absence of inflammatory root resorption.
What is a sterile dressing?
Traditionally, this was calcium hydroxide paste. Now, the material of choice is
called MTA (mineral trioxide aggregate). This is essentially a sterile, medical
grade Portland cement. It is produced in sterile powder form (e.g. ProRoot MTA,
iM3 MTA Powder) and contains calcium oxide, bismuth oxide and various
calcium silicates. It is a white powder, mixed with sterile water to produce a
highly alkaline paste which sets hard. The pulp is not inflamed by this, and in
fact may produce a new dentinal bridge under the material.
What is the success rate for VPT using MTA?
success rates when
using MTA, can be as high as 92 %
What is the sandwich technique?
- MTA (mineral trioxide aggregate) layer first.
- Glass Ionomer layer next.
- Composite
restoration, to seal the crown.
In fractured immature teeth why is it not possible to perform a RCT?
In fractured immature teeth, it is not possible to perform traditional root canal
therapy if the apex is not formed.
What is apexification?
A procedure known as apexification can be
performed in order to produce an artifical bridge at the apex, upon which
traditional RCT can be performed. The working length to the apex is carefully
measured, and then MTA is placed at the apex, and a calcium hydroxide paste
used to fill the rest of the canal, plus a temporary restoration. After 6 weeks, the
restoration and paste are removed and if a solid bridge has formed, the canal
can be filled with a sealer, followed by a final restoration. This can end up being
very expensive, involving multiple anaesthetic episodes, to save one tooth.
What is surgical endodontics?
Surgical endodontics involves performing an apicoectomy ( a resection of the
apical part of the root), surgical debridement of the periapical tissues, and a
retrograde filling of the apical pulp cavity (Fulton et al 2012). It has been used
as salvage procedure in humans, when standard (orthograde) root canal
therapy has failed. In dogs, if root canal therapy fails, the tooth can be retreated in a conventional manner, extracted or surgical endodontics can be
performed. In Fulton’s case series of 15 dogs, 10 were successful, and 5
showed no evidence of faliure, meaning this is a viable option for cases which
fail after standard root canal therapy. The apex of maxillary canine and 4th
premolar teeth and mandibular 1st molar must be approached surgically via a
mucosal flap, and the mandibular canine extra-orally through the skin of the
ventral mandible. Once the apex is identified radiographically, an osteotomy is
performed using a bur on a high-speed handpiece to reveal the root apex. This
allows debridement of periapical area and resection of the apical 4mm of the
root at a 90 angle to the long axis. The most apical 3mm of the root canal
space is then cleaned using a special diamond coated ultrasonic tip, and then
filled using MTA. The mucosa/skin is then closed routinely and follow-up
radiographs obtained after 3 months.
What is apicoectomy?
A resection of the
apical part of the root
