Zeta, a female 13 week old English Staffordshire Terrier was referred following presentation at her regular veterinarian for a routine vaccination. During the examination lingually displaced right and left deciduous canine teeth were noticed to be traumatising the diastema of the hard palate bilaterally.
Weight 5.2kg, T 38.9, HR 168, RR 20, mmem pink and moist crt < 2 secs, Mentation bright and alert, Body condition score 5/9, hydration nad. On oral examination linguo-version of the deciduous mandibular canines (704/804) was noted. The canines were impacting on the hard palate, there was trauma and contact and mild ulceration.
It was recommended that 704 and 804 be extracted as soon as possible to relieve the unfavourable trauma and inflammation, relieve pain and give the permanent mandibular canine teeth (304/404) every opportunity to erupt and achieve normal occlusion. At 13 weeks of age, there is only a short period in which extraction will yield a favourable outcome. Ideally extractions of this nature are undertaken at 7-8 weeks of age and no later than 12 weeks of age1. This is primarily because the crown of the canine tooth forms between 8 and 13 weeks of age, which is followed by root formation and crown/tooth eruption. If the deciduous teeth remain persistent, it is highly likely the permanent canines will erupt further lingual to the deciduous teeth. Zeta’s owner was advised that malocclusion of the permanent canines was highly likely without treatment and she may require further surgery to assist in the positioning of the adult teeth even after surgical extraction of the deciduous teeth. In animals with serious malocclusions, where dental contact or advanced soft tissue injury occurs, extraction of the deciduous teeth may not relieve the problem due to the genetic influences on jaw growth.
Anaesthesia and pain management:
Pre-anaesthetic blood profile including haematology and biochemistry was run on an Abaxis machine and were within normal limits.
IV fluid therapy using Hartmann’s solution @ 3ml/kg/hr was commenced after placement of an indwelling #24 catheter in the right cephalic vein at premed. The flow rate was increased to10ml/kg/hr peri-operatively and continued for 2 hours post-op
Premedication: Acepromazine 0.2mg Buprenorphine 60mcg Atropine 0.25mg SC simultaneously
Induction: Alfaxalone 12mg IV slowly to effect
Maintenance: Isoflurane 1-3% in 100% oxygen via a cuffed #6 endotracheal tube
Local nerve blocks: Mental blocks using 0.25mls mepivacaine 3% solution in an aspirating dental syringe
Post-op analgesia: Meloxicam injectable 2.5mg SC on recovery and 0.75mg once daily for 2 days PO with food.
After stable anaesthesia was achieved, Zeta was monitored using a Cardell 9403 veterinary machine to measure blood pressure, spO2, temperature, heart rate, and respiratory rate. Zeta was kept warm using an air forced heating blanket. The mouth was thoroughly examined. The lingually displaced canines (804 and 704) were radiographed prior to extraction . Local analgesia was administered using mental nerve blocks bilaterally.
Extraction of 804 was undertaken first followed by 704. The epithelial attachment and periodontal ligament was severed using a Molt 2/4 periosteal elevator and a feline curved deciduous tooth elevator. Great care was taken not to lever against the underlying crowns and developing tooth buds of 304 and 404, which are positioned on the lingual aspect of the deciduous canine teeth. Taking care to reduce inflammation, reduces the surrounding temperature, thus avoiding any damage to the enamel of the developing permanent dentition, as the ameloblasts are sensitive to temperature change.
Initally the Molt periosteal elevator is introduced into the gingival sulcus and with firm but controlled force used to sever the epithelial attachment around the entire circumference each tooth. The elevator is advanced apically on the lingual and buccal surfaces of the canine root to approximately 75% of its length. The curved deciduous elevator is introduced into the gingival sulcus to sever the mesial and distal periodontal ligament using the concave surface against the mesial root and convex surface against the distal root. Once the tooth begins to become mobile, the Molt was reintroduced into the lingual aspect and gently rotated moving the tooth laterally. Each tooth was grasped with the small animal extraction forceps and gently removed from the socket with gentle rotation Both 704 and 804 were removed in their entirety , which was confirmed by radiography.The sockets were checked to ensure a blood clot was present and left open to granulate.
Post operative instructions:
Re-evaluation in 15 days post-op was conducted to fit in with the owner’s schedule. Her owner was advised to monitor the extraction sites for any abnormal swelling or discharge and was asked to offer food which could be squashed between the thumb and forefinger, without being mushy.
Zeta is to re-examined on eruption of the permanent canines and revisit once they have erupted 5mm through the gingiva. Results will be posted on the ‘case study’ forum once available.
Further treatment options:
The owner was advised that there are 4 treatment options to consider if the permanent teeth erupt linguo-verted:
1.Coronal extensions to direct the erupting teeth into the appropriate position.
2.Placement of an incline plane to orthodontically tip the mandibular canines laterally.
3.Crown amputation and direct pulp capping
4.Extraction of the mandibular canines.
The follow-up progress of this case will be posted once available.
The above four treatment options will be presented as case studies over the next few months.
- Wiggs RB, Lobprise HB Veterinary Dentistry Principles and Practice.Philadelphia:Lipincott-Raven 1997