Equine dentistry 2

What are the malalignments in equine?

• Brachygnathism (congen)

  • Parrot mouth

  • Overjet/Overbite

• Prognathism

  • Sow mouth

• Campylorrhinus lateralis = wry nose

What is brachyganthism? How do you treat it?

• Overly long maxilla compared to mandible —> maxillary incisors lie rostral to mandibular ones

  • no wearing down of opposing teeth —> problems with overgrowths

  • cheek teeth not opposing each other → sharp hooks at back of mouth

• Severe cases —> option of surgical correction (ethical?)

What are the consequences of brachygnathism?

• Ulceration of behind upper incisors

• Maxillary rostral 06 overgrowths and mandibular 11 overgrowths will need lifelong attention

What is prognathism? What are the clinical implications?

• Relative overgrowth of mandible

  • Miniature breeds over-represented

• Clinical Implications

  • Few incisor problems

  • Develop lower 06 overgrowths and upper 11 overgrowths

    • i.e. opposite to normal

• Check back of mouth for overgrowths

What is campylorrhinus lateralis (“wry nose”)?

Deviation (& occasional rotation) of entire maxilla involving incisive region, nasal septum & nasal bones

What are the varying degrees of severity of campylorrhinus lateralis?

• Minor occlusal problems —> routine dentistry every 6 months

• Severe = difficulty nursing & occlusal → breathing problems

Surgical correction can be attempted but complex

What is diagonal bite/slant mouth indicative of?

• Eating predominantly on one side

• May indicate shear mouth formation of cheek teeth

Which species is smile mouth normal in?

Donkeys

What is being shown here?

• Retained deciduous incisor

  • Usually rostral & causes caudal displacement of permanent tooth

How are retained deciduous incisors treated?

• Loose —> remove with forceps

• Firmly attached —> remove with dental elevators

• May need to radiograph (easy for incisors & front of mouth)

How do supranumerary incisors present?

• Have long crowns (up to 7cm)

• Close to reserve crowns and roots of normal permanent incisor

How are supranumerary incisors treated?

• Usually cause little problem

• Often best not to remove

What causes incisor fractures?

• Trauma

  • Kicks

  • Inquisitive youngstock caught on objects —> e.g. haynets

  • Crib-biting on fixed objects

What are the two ways that incisors are fractured?

• Involve the incisive bone —> may look dramatic but quite easy to reapir, do not remove fragments if repair possible

• Incisors themselves —> determine if pulp affected, endodontic repair or extraction

What are incisor diastemata?

• Spaces between adjacent teeth

  • Shouln't be any

  • May develop with age as incisors taper towards apex

  • Can lead to periodontal dx

What is valve diastema(ta)?

• Narrower at occlusal aspect

• Wider at gingival margin

• Trap food causing gingivitis, periodontitis & potentially

How do you manage incisor diastemata?

• Remove food from spaces

  • Owner can perform this with a toothbrush x2/week

What is EORTH?

Equine Odontoclastic Tooth Resorption & Hypercementosis

• Unknown aetiology —> horses aged >14yrs

• Swelling and/or draining tracts over multiple mandibular & maxillary incisors

  • pain + difficulty prehending food

How do you diagnose EOTRH?

• Diagnosis —> visual + radiography

  • Lytic changes / hypercementosis

How do you treat EOTRH?

• Extraction of loose incisor curative

• Disease progressive in some cases spreads from tooth to tooth

• May have to remove all incisors

How are oral neoplasia's classified?

• Tissue of origin —> dental, bone, soft tissue

• Clinical behaviour + patholoigcal features —> benign/ malignant; invasive/ localise; proliferative / ulcerative

What are the oral neoplasias of dental origin?

• Ameloblastoma

• Cementoma

• Odontoma

• Temporal teratoma

What are the features of ameloblastomas?

• Most common in:

  • Older horses

  • Mandible

• Cause a bony swelling

  • +/-cystic cavity

• Benign/locally invasive

• Surgical excision —> poss specialist removal of mandible

What are the neoplasia of soft tissue origin?

• Squamous cell carcinoma (SCC) (most common)

• Sarcoid

• Epulis

• Melanoma

• Oral papilloma

• Ossifying fibroma

• Fibroma

• Myxoma/Myxosarcoma

(tx depends on cause, extent & location)

What are the abnormalities of the canine tooth?

• Calculus around lower canines most common

  • Remove with dental forceps

  • Owner can clean periodontal pockets

    

• Apical infection/fracture

  • Endodontic treatment can be considered in some cases

  • Removal challenging —> long teeth w/ curved roots deeply embedded in bone

    

What are the abnormalities of the wolf teeth?

• Number, position size variable

• Do not cause problems when in normal position and of normal size

(be careful of palatine artery)

What are the indications for wolf tooth removal?

• Biting problems/ ulceration

  • Rostrally displaces, particularly large, mandibular

• Loose or displaced

• Blindly erupted (painful)

• May become molarised (looks like molar) —> always radiograph

How are wolf teeth removed?

• Specialist kit —> incl. apple-core device (Burgess elevator) to go around tooth

• Can use a long handled elevator / small animal tooth luxator & pair of SA forceps

What complications can you get with wolf tooth removal?

• Fracture of tooth

• Fracture of bone

• Trauma to the palatine artery → marked haemorrhage

Describe wolf teeth removal

• Standing sedation + speculum placed

• LA —> infra-orbital / maxillary nerve block → direct infiltration

• Use dental elevators circumferentially around tooth to loosen it (be careful of palatal artery)

• Remove w/ forceps once loose —> don’t extract until fully loose because risk of breaking tooth

  • if occurs & small subgingival fragment → try to remove

• 2 weeks bit rest

What are the two classifications of cheek teeth issues?

• Developmental

• Acquired

When are cheek teeth first examined?

Ideally briefly in 1st week of life @ same time checking for cleft palate

How often are cheek teeth checked?

Yearly as they begin to erupt

What are eruption cysts?

• “3-4 year-old bumps”

• Palpable swellings on mandible ventral to apices of Triadan 07/08

• Physiological & transient phenomenon

  • Should not be considered as disorder

What are retained caps?

• Remnants of deciduous teeth

  • Normally shed during eruption of the underlying permanent tooth

• Loose / retained caps can cause oral pain / quidding

• Usually attached to gingiva in one place, attachement causes pain

How do you treat retained caps?

• Easily removed with forceps

• If possible contralateral cap should be removed

• Do not remove prematurely —> will damage developing tooth

What is the cause of cheek teeth displacements?

Overcrowding during eruption

How do cheek teeth displacements present?

• Often bilateral

• Usually 09s & 10s

• Medial / lateral displacement +/- Rotation

What do cheek teeth displacements lead to?

• Buccal/lingual trauma

• Diastemata → periodontal disease

What are developmental disatemata?

Cheek teeth occlusal surfaces should be tightly compressed together —> act as one functional grinding surface

If teeth develop too far apart

• Spaces develop

• Food accumulates

• Fermentation

• Periodontal disease

Where do supranumerary CT develop?

Usually at caudal aspect —> so count teeth!

(+ dental dysplasia + oligodontia)

How do you deal with supernumerary CT?

• Incidental

  • Can be left but if not occluded then need to rasp regularly to prevent overgrowth

• If cause periodontal disease then extract

Where do enamel overgrowth occur?

• Buccal aspect of upper CT

• Lingual aspect of lower CT

Due to anisognathism

What are the clinical signs of enamel overgrowths?

• Quidding, pain when eating, +/- colic

• Tack may exarcerbate

• More pronounced when horses fed more concentrate bc unnatural masticatory pattern

• Tack may exacerbate problem —> mucosal ulceration

How do you treat enamel overgrowths?

Removal during routine dental prophylaxis

What is wavemouth? How do you treat it?

• Marked undulation to occusal surface

  • If mild —> little tx required

  • Dominant areas can be sequentially reduced every 3 months

What is stepmouth? How do you treat it?

• When a focal overgrowth occurs

  • Usually opposite a missing or extracted tooth

• Reduced in stages to prevent pulpar exposure or thermal damage

What is shear mouth?

• Increase occlusal angle of entire cheek tooth row

• Usually 2° to diastemata formation or dental fracture

What should you suspect if shearmouth is bilateral?

Temporomandibular joint arthropathy (joint dx of jaw)

How is shearmouth managed?

• Treat 1° problem

• Gradual reduction of angle should be performed

  • Occurs rapidly anyway when horse begins to chew more normally

What is being shown here?

Exaggerated transverse ridges

• Do not confuse with normal ridges

  

• Often opposing diastemata

How do you remove large overgrowths?

• Hand or power rasps (careful of thermal energy)

• Reduced in stages

  • Max 3-4 mm q 6 months

What are the problems with excessive rasping?

• Pulp exposure

• Thermal damage

• Risk apical infection

• High risk sites:

  • Rostral 06s + Caudal 11s due to extra pulp horn

What is bit seating?

• Rostral profiling (to prevent bit impingement but misconception —> bit should not sit in this location)

• CONTRAINDICATED —> extra pulp horn on 06s

  • pulp horn exposure

  • apical infection (18months)

What is smooth mouth?

• Senile change

  • Cheek teeth enamel largely worn away

  • Sometimes worn down to individual roots

• Softer dentine and cementum become smooth

  • Not very useful for grinding

How do you manage smooth mouth?

• Dietary mangement

  • e.g. feeding chopped forage to help maintain weight

What locations can caries affect?

• Peripheral cementum of the maxillary and mandibular cheek teeth

• Infundibulae of maxillary cheek teeth

How do dental caries occur?

• If food material becomes stagnated in pits of peripheral cementum

  • Fermentation

  • Drop in pH of envioronment

  • Deminerlisation

  • Pits bigger and blackening of the peripheral cementum

• Cementum becomes eroded then may spread into peripheral enamel

What causes infundibular caries?

• Developmental predisposition

  • Cemental hypoplasia

  • Food accumulates in infundibulum

  • Fermentation → decay

  • Young horses may have small central opening = site of former infundibular central artery

(progressive & irreversible)

What do infundibular caries predispose a horse to?

Fracture

How are infundibular caries managed?

Infundibular restoration

What are the causes of peripheral caries?

• Increase sugar in diet

  • Haylage

  • Molasses

(Common)

How are peripheral caries managed?

• Palliative rasping of roughened cementum

• Removal of excess sugars from diet

• Oral lavage

What does treatment of diastemata depend on?

Severity of periodontal disease

How do you treat diastemata without periodontal disease?

• Must be cleaned out COMPLETELY

  • Dental Pick / Diastema forceps / High pressure lavage

• Remove ETR’s (exaggerated transverse ridges) on opposite arcade and correct other overgrowths that may be contributing to diastema

• +/- Pack w/ impression material to prevent refilling

How do you treat diastemata with periodontal disease?

• Widen with mechanised burr

  • Painful —> lidocaine splash block

• Remove ETR’s on opposite arcade and correct other overgrowths that may be contributing to diastema

• +/- Pack w/ impression material to prevent refilling

• Dietary management essential

  • Short fibre —> grass / ‘short chop’

  • Avoid long stem hay / haylage

What are the 3 main types of cheek teeth fractures?

• Buccal (lateral) slab fracture

• Midline sagittal fracture

• Occlusal fissure fractures

(v. rarely due to trauma)

How do buccal fractures usually present?

• Can be incidental

• Quidding

• Usually NOT associated with apical infection

How do you treat buccal fractures (slab fractures)?

• Pulp horns seal off —> calcium hydroxide may encourage this

• Dental extraction may not be required but remove loose fragment

What are the features of midline sagittal fractures?

• Most commonly 109 & 209

• Pathological fracture through infundibulae

  • Preceded by infundibular caries

• Result in apical infection +/- sinusitis

How do you treat midline sagittal fractures?

Extraction

What are the features of occlusal fissue fractures?

• Incidental finding, subtle

  • Require dental mirror/oroscope

• Unknown significance

• May predispose to atypical fracture

  • Different configuration

• Monitor

What do the clinical signs of an apical infection depend on?

• Which cheek teeth are involved

• Location in relation to paranasal sinuses

What are the clinical signs of apical infection and which cheek teeth are they related to?

What are the sequelae of pulpitis?

Pulpar oedema → vascular occlusion → necrosis

What are the causes of apical infections?

1. Anachoresis (= blood borne infection)

2. Fracture

3. Periodontal spread (Diastema)

4. Pulpar exposure

What are the routes of infection of mandib / maxil CT?

How is apical infection diagnosed?

• Clinical signs

• Oral exam

  • Fracture, pulpar exposure

• Imaging

  • Rx, CT (better), Nuclear scintigraphy

What are the options for cheek tooth extraction?

1. Oral extraction

2. Modified transbuccal extraction

3. Lateral buccotomy

4. Repulsion

(complications poss —> preservation of alveolus important where poss)

What is the sedation of an oral extraction

• Regional anaesthesia (nerve + local blocks)

• Heavy sedation

• NSAID & antimicrobial

How is an oral extraction performed?

(Vet surgeon only)

1. Gingival elevation and periodontal ligament disruption with picks

2. Interdental spreading (closed gradually and incrementally in interdental space to stretch periodontal ligament over approx 30 mins)

   

3. Application of extraction forceps

How are molar forceps used?

• Oscillate (gently wiggle to stretch periodontal lig) lateral strain (horizontal rocking) & fulcrum (elevation)

• Must be tightly applied to tooth or else risks damage

• Many different types depending on tooth shape

When are Minimally-invasive transbuccal extractions (MTEs) used?

• When crown fractured

• Oroscopic & radiographic guidance

• Preserves alveolar bone

How are MTEs performed?

• Chisels to break down ligament

• Reserve crown drilled

• Hole tapped

• Extraction screw inserted

• Pulled out orally using mallet

• Picks, chisels & fragment forceps

When are repulsion cases used?

• Complex cases only

  • Must be loosened as much as possible first

  • GA / sedation with LA

  • Rads guidance imperative

How are repulsions performed?

• Trephine over top of tooth

• Blunt instrument to drive tooth into mouth

  • Mechanically inefficient

  • Alveolar bone damage

    • Steinnman pin= minimally invasive

      

    • Dental punch = very destructive

      

(high potential for complications)

How is a lateral buccotomy performed?

• GA often required

• Incision through cheek

• Removal of lateral alveolar bone

• High morbidity (Iatrogenic trauma potential damage to facial nerve & parotid duct + wound breakdown)