Equine dentisry 1

What dentition pattern do horses have?

Hypsodont = long crowned

What diet do horses have and how long do they graze for?

Grass diet —> abrasive

Graze for 18hrs / day

What is the eruption time of horse's teeth?

2mm/ year

What is the dental formulae of equids- deciduous and permanent?

What is the triadan numbering system for permanent horse teeth?

What is the deciduous triadan numbering system for horse teeth?

What are the eruption times for deciduous incisors of the horses?

01s (central) = 1 week

02s (middle) = 6 weeks

03s (corner) = 6-9 months

(Easy to remember 6 days, 6 weeks, 6 months)

What are the eruption times for permanent incisors of the horses?

What is the eruption time for canine teeth?

5 years

(In males, occasionally females)

(no deciduous precursor)

What is the eruption time for wolf teeth?

1 year

(Many lost with 06 cap —> 2.5 years)

(1st PM)

(no deciduous precursor)

What are the eruption times of the cheek teeth?

PMs —> 06, 07, 08 present at birth

• Cap shedding time very variable

Ms —> No deciduous precursor

What does this radiograph show?

Dental caps, only on PMs

Recall the different layers of the tooth

What are the general features of the horse tooth anatomy ?

Irregularly formed laminate of tissues with different properties

Why is the tooth anatomy irregular?

Complex folds/ridges increase amount of enamel present on occlusal surface & total surface area of enamel available

Why does the tooth anatomy have a laminated structure?

Dentine & cementum interspersed between enamel folds protects brittle enamel from cracking & form irregular occlusal surface due to differential wear

Recall the features of enamel

• Hardest substance in body

• Brittle

• No capacity to heal if damaged

• Almost translucent in horses

Recall the features of dentine

• Majority of tooth

• Cream coloured

• Calcified tissues

• Produced by odontoblasts

• Four subtypes of dentine

  • 1°, 2° (regular and irregular), 3°

Recall the features of cementum

Outermost layer of tooth (& fills infundibulum) similar to bone, attachment between tooth & periodontal lig

Recall the features of pulp

• Contains vital structures (nerves, blood supply, lymphatics and odontoblasts)

• Variable distance from occlusal surface (1mm-36mm)

How does the appearance of the incisor change throughout the years?

• Infundibilum (lingual side) & dentine star become visible at 4 years

• More triangular and then more round when older

(age related to pre-purchase examination when buying horse)

Why is ageing teeth inaccurate?

• Individual variation (genetics)

• Uneven wear (diet & environment e.g. crib biting )

Label the cheek tooth

How does the cheek tooth anatomy vary between the maxillary CT and mandibular CT?

• Maxil = prone to carries, squarer

• Mandib = narrower

What are pulp horns?

• Area of pigmented 2° dentine on occlusal surface (approx 5mm thick)

• Protect underlying pulp

• Every cheek tooth >5 pulp horns

  • 06s + 11s have extra pulp horns

    • 06 = rostrally

    • 11s = caudally

What is this showing

Maxillary cheek teeth

• 2 infundibulae (enamel cups) = red

• >5 pulp horns = green

Where are the maxillary cheek teeth located?

• 06 + 07 → Maxillary bone

• 08 + 09 → Rostral maxillary sinus

• 10 + 11 → Caudal maxillary sinus

What is the clinical relevance of the location of the cheek teeth?

• Presentation of maxillary tooth infection dependent on location (whether sits in bone or sinus)

What are the features of the mandibular cheek teeth?

• No infundibulae

• >5 pulp horns

• Narrower bucco-lingually compared to maxillary cheek teeth

How many roots do mandibular cheek teeth have?

• 2 roots (rostral and caudal)

• 06-11 = mandible

What is the clinical relevance of location of mandibular cheek teeth?

What is anisognathia?

• Maxillary CT 20-25% further apart than Mandibular CT —> mandib CT sit closer to teeth

  • Relevance = location of spurs

  • Able to grind teeth more effectively

    • overgrowths form if not grinding properly → sharp

What is the widest point of the curvature of the maxilla? What are the implications of this?

Widest 08-10

Implications:

• Tack

• Removing buccal overgrowths follow curve

What is the curve of spee?

• Curving upwards of cheek teeth

  • take care when trying to remove caudal 11 overgrowths

• More pronounced in Arabs

What do you need to prepare for a dental exam?

• Dental equipment, gloves, water

• Lighting and appropriate area

• Recording sheets

• +/- Sedation —> alpha 2 agonists, butorphonol

• +/- head stand

List the basic dental equipment

• Gag/Speculum

• Light source

• Dental mirror

  

• Dental Syringe

  

• Pulpar explorer

  

• Periodontal probe

• Diastema forceps —> to pick bits of grass out between teeth

• Rasps

• +/- motorised tools

What should you do in the initial examination of a horse?

• Thorough history

  • Recent weight loss, colic, rubbing, headshaking, feed type

    • duration of signs

• Watch the horse eat —> normal grinding sounds?, chew on both sides?, take longer to chew?, quidding?

  • quidding = partially masticated food due to pain —> balls of food spat out (horses good at covering it up)

• General clinical exam

  • Signs of underlying disease

  • External swellings or asymmetry

  • Draining tracts

  • Halitosis

  • Nasal discharge

What should you do in the incisor examination?

• Check for any abnormal masses / fractured teeth

• Check occlusion from side —> over / underbite

  • performed in neutral position

• Check occlusion from front —> slant / smile mouth or evidence of crib biting

• Check lateral excursion —> movement of maxilla & mandible laterally

• Count teeth —> supranumerary, missing, retained deciduous

How do you examine canines and wolf teeth?

• Place speculum

• Flush mouth

Check canines —> calculus formation, fractured canines, apical infection

• Wolf teeth —> palpate bars to check

  • Displaced, loose, blindly erupted, mandibular

  • Has bit come into contact with them?

What are the four steps of the cheek teeth exam?

1. Palpate

2. Look without mirror - count teeth

3. Look with mirror - count again, every inter-dental space

4. Probe

What should you palpate in the first step of your oral exam?

• Occlusal surface of every tooth

• Edges of all teeth particularly:

  • buccal aspect of Maxillary CT

  • lingual aspect of Mandibular CT

• Every inter-dental space

• Buccal mucosa

• Tongue adjacent to the teeth

• Especially opposite pathology

What is being assessed in the oral exam?

What should you probe in the fourth step of the dental exam?

Teeth of concern

• Every pulp horn

• Assess depth of diastema

What is being assessed with the probe?

How is oral endoscopy helpful?

• Better evaluation of occlusal surface

  • Fissure fractures

  • Subtle dentinal abnormalities

• Better evaluation of diastemata & periodontium

What are the methods you can use for routine floating?

• Hand rasps

• Motorised equipment

  • Disc vs apple core

  • Variable angle

(before = can cause ulceration due to sharp points)

(after = smoother)

How do you document findings from a dental exam?

• Dental chart —> give record to owner + one for yourself

• Discuss findings and plan treatments

  • further diagnostic imaging?

What further diagnostic imaging can you do to evaluate dental disease?

• Radiography

• Sinoscopy

• CT

• Scintigraphy

• Magnetic resonance imaging (MRI)

What procedures are classed as category 1?

Can be performed after recognised training w/o specific attainment of qualifications

• Examination of teeth

• Removal of sharp enamel points using manual rasps only

• Removal of small dental overgrowths (maximum 4mm reductions) using manual rasps only

• Rostral profiling of the first cheek teeth (maximum 4mm reductions), previously termed ‘bit seat shaping’

• Removal of loose deciduous caps

• Removal of supragingival calculus

What are category 2 procedures and who can perform them?

Cat 2 = EDT passed DEFRA exam

• Examination, evaluation and recording of dental abnormalities

• Removal of loose teeth / fragments with negligible periodontal attachments

• The removal of erupted, non-displaced wolf teeth in the upper or lower jaw under direct and continuous veterinary supervision

• Palliative rasping of fractured and adjacent teeth

• Motorised dental instruments to reduce overgrowths and sharp enamel points only

• Horses should be sedated unless it is deemed safe to undertake any proposed procedure without sedation, with full informed consent of the owner

What are category 3 procedures who can perform them?

Category 3 procedures may only be performed by qualified veterinary surgeons

• Diastemata widening

• Unerrupted wolf tooth removal

• Teeth extractions

(only qualified vet surgeons can dispense POMs + administer / owners can administer)