Flashcards in Equine Dentistry 1&2 Deck (55):
What are the cheek teeth?
PM2-4 and M1-3
High-crowned teeth and enamel which extends past the gum line. An adaptation for constant grinding (also irregular enamel ridges help break down cellulose).
What is the name of the system of dental nomenclature?
Triadan system - first number indicates arcade, second number indicates tooth. (maxillar right =1 ; maxillary left =2, mandibular left = 3, mandibular right =4).
When do the first incisors erupt?
When does the first molar erupt?
What is the vestigial first premolar tooth?
05. The wolf tooth
When would the 2nd premolar erupt?
Maxillary arcade wider than mandibular arcade
Define the 'Curve of Spee'
the upward slope of occlusal surface at the caudal aspect of mouth.
How does the infundibulum differ between maxillary cheek teeth, mandibular cheek teeth and incisor?
Maxillary cheek teeth - 2 infundibulae in each
Mandibular cheek teeth - no infundibulum
Incisor - 1 infundibulum in each
When would you perform a dental exam?
Annual check (prophylaxis)
If owner notices a problem (swelling/discharging tracts, wt loss, quidding, headshaking, bitting problems, unilateral nasal discharge)
What are the components of a dental exam? (4)
External examination (BCS)
Head examination (symmetry, swelling, LNs, nasal discharge, pain on palpation)
Oral examination (inicisors prior to speculum for malocclusion, interdental space for wolf teeth, canines, bitting injuries, tongue injuries, cheek teeth)
What considerations are needed for an oral exam? (4)
Head support (if sedated)
Gags (full mouth speculum) - Hausmann's gag or wedge gag (for incisors)
What pathologies should be checked for in cheek teeth
Buccal and lingual poinnts, buccal/tongue ulceration, deciuous caps/reminants, focal overgrowths, molar table angle, wave mouth, step mouth, fractured teeth, diastema, excessice transverse ridges, foreign bodies, periodontal disease, caries (infundibular in maxillary arcades and peripheral)
Where do points form?
buccal edge (maxillary arcade) or lingual edge (mandibular arcade). Associated with anisognathism (upper jaw larger than lower jaw).
What do enamel overgrowths cause? (5)
Prevent jaws moving freely, oral pain (-->quidding and weight loss), bitting problems, headshaking, severe cases develop shear mouth
Occlusal angle >15 degrees
Treatment - shearmouth (4)
Reduce buccal and lingual points,
reduce angle starting at high side,
regular treatments every 3-6 months, address any underlying pathology
Name the 2 blades used for routing rasping of points (and advantages/disadvantages)
-Carbide chips blades (cheap, robust, for minor routine work, hard work to remove hooks)
- Solid tungsten carbide blades (expensive, brittle, excellent for routine work, remove hooks well, often cut only one way - towards you)
What are the different shapes of blade for rasping and their uses? (4)
Straight head, long lenght (all lower cheek teeth, 3-6 upper cheek)
-Obtuse angled head, long length (caudal upper cheek teeth, curve of spee)
-angled offset head, medium length (upper 1-4 cheek teeth)
-S float (to smooth off first cheek teeth and 6th maxillary cheek teeth, bit seat, angle of curve of spee).
What do you need to be careful of when using power tools to remove hooks quickly?
Palatine artery (run medial to upper arcade).
What are caps? Consequence of these? Treatment?
Retained deciduous premolars. Normally shed at 2.5, 3 and 4 years.
RESULT = anorexia, poor performance, malocclusion
TREAT = remove (with forceps or screwdriver) carefully to avoid damage to underlying tooth.
Where are rostral and caudal overgrowths normally found (4)? What are they associated with? (2)
106, 206, 311 and 411. Associated with parrot mouth and disparity of cheek teeth rows.
Causes of focal overgrowths (4)
Why do overgrowths increase risk of pulp exposure?
Overgrowths have decreased occlusal contact and decreased secondary dentine therefore increased risk of pulp exposure.
Define wavemouth. Treatment?
=at least 2 M or PM are higher than others giving appearance of a wave from the side.
TREAT= reduce them gradually, start at highest point.
How do you identify pulp exposure? Causes? (2)
Probe secondary dentine overlying pulp horns
Cause = apical tooth infections (or a consequence of this) or overzealous rasping
What can be the result of infundibular caries? (2)
Septic pulpitis and sagittal fracture of the tooth.
Are infundibular caries common?
Yes - 80% horses >15 years old. Usually benign.
How do you treat excessive transverse ridges?
Reduce individual larger ridges whilst maintaining normal ridging in place (normal height unknown)
Tissues surrounding and supporting the teeth (gingivae, periodontal ligament, alveolar bone, cementum etc).
Describe periodontal disease in horses.
Primary disease = rate. Caused by diastemata.
Most painful dental disease
Most commonly mandibular cheek teeth
Draft breed predisposition?
Incidence increases with age.
Outline stages of periodontal disease
localised gingivitis with pocket formation - trapped debris stagnates and undergoes secondary formation - vFAs erode down to periodontal ligament. Feed compressed during mastication - deepens pocket. Alveolar bone destruction (localised osteomyolitis). Bacteria enter pulp cavity through root canals. Usually begins in interproximal space.
Many individual diastema are clinically silent (at least initially). When does this change? Diagnosis? Treatment?
Food trapped between teeth packs into periodontal spaces --> pressure --> pain --> quidding.
Can (rarely) lead to bone infection.
DIAGNOSIS = difficult, open mouth radiography. Usually caudal lower cheek teeth. Small diastema can be more problematic than a large one.
TREATMENT = varies (monitoring/widening/extraction). Management - replace long fibre food with short chopped foods and remove overgrowths opposite diastemata essential. Widening - vet only, danger of opening into pulp and overheating. Extraction of impacted food - use lng handled dental pick, high pressure water or air picks (but only transient improvement).
Distinguish congenital and acquired cheek teeth displacements. Consequences? (2)
-DEVELOPMENTAL = overcrowding of arcades during eruption, often bilateral, usually 4th/5th cheek teeth, medial or lateral displacement, tooth rotated.
-ACQUIRED = more common, usually lower 10s and 11s in old horses.
RESULT = diastema and periodontal disease.
When may cheek teeth fracture? Result? (2)
Cause = secondary to severe infundibular caries
Result = septic pulpitis, acquired overgrowths
Clinical signs - mandibular apical tooth infections (7). Diagnosis?
Most common in younger horses (mean age =5 years)
asymmetrical jaw swelling, ventral discharging tract, oral involvement (rare), quidding (unusual), halitosis (associated with specific abscess rather than generalised whole mouth), submandibular LN enlargement.
DIAGNOSIS = simple, radiography
Aetiology of apical tooth infections (5)
premature pulp exposure (during wear)
pulp exposure after transverse fracture
iatrongenic (excessive rasping)
Distinguish maxillary apical tooth infections 06 and 07 versus 08 to 11.
06 and 07 (i.e. PM2 and 3) = apices are situated within the maxillary bone, may burst into nasal cavity (rare), diagnosis = xray
08 to 11 (i.e PM4 and M1-3) = apices situated in rostral and caudal maxiallary sinuses. Sinusitis --> unilateral nasal discharge. DIAGNOSIS = which tooth? oral exam often insufficient, radiog/scintig/sinoscopy/CT
Advantages/disadvantages of oral endoscopy.
+ = magnified visualisation of occlusal surfaces, examine back of oral cavity, use rigid or fibre optic scope, reliable speculum
- = equipment is delicate, expensive and hard to disinfect.
What is latero-lateral (lateral) horizontal beam projection radiography?
Exudate within paranasal sinuses appears as flluid lines. Teeth apices are superimposed preventing visualisation.
Describe lateral-45 degrees ventral lateral oblique radiography.
Reduced superimposition of mandibular apices. Place plate on side you wish to examine.
What is the most common equine tooth to be infected?
09 = Molar 1 = cheek tooth 4. Reason = it is the oldest cheek tooth in the horse's mouth (erupts when horse is one year old).
What sensitivity and specificity does dental radiography have?
Low sensitivity (approx. 50% chance of detecting a dental infection) and high specificity.
What are radiographic signs of dental disease?
Absence of teeth, malpositioning, crown deformation, radicular distortion (ragged appearance), loss of the lamina dura denta, periapical lucency (halo), cementosis (becomes more dense), localised maxillary bone proliferation - osteitis (coarsening and compaction of bone trabeculae).
What sensitivity and specificity does gamma scintigraphy have?
Sensitive (picks it up but won't tell you which tooth), but only moderate specificity.
How clear is sinoscopy for dental sinusitis?
What is a voxel?
A 3D pixel that creates an image from a CT scanner. Each voxel has a value in Hounsfield units (HU). The size of the HU changes depending on tissue (bone>soft tissue>air).
Advantages of CT for dental diagnoses? (3)
-View in multiple planes and dimensions
What are the signs of apical tooth root infection (radiographic and CT)?
-Periapical sclerosis and periapical halo (mainly)
-Clubbing of tooth roots
-gas within the bulging root area
-fragmentation of the root
-increased pulp volume
-abnormal pulp morphoplogy
Define supernumerary tooth
An extra tooth. Often bilateral. Usually have a diastema leading to food accumulation. HArd to determine which tooth is the extra one (the smaller one?)- often remove the most caudal one.
Treatment options - apical tooth infection (4)
Conservative - ABs
Currettage (rarely works)
Tooth removal (repulsion - high complication rate; extraction - treatment of choice, a third of the number of complications as repulsion, difficult in caudal cheek teeth of young horses. now possible in comminuted fratures and when no occlusal surface), by lateral buccotomoy.
Endodontic treatment (currently poor success rate)
What are the stages of oral extraction? (6)
Sedation, local blocks (e.g. maxillary nn), separation, placment, grip, patience.
Describe wolf teeth.
No deciduous precursors, erupt at approx 1 year of age, many lost when 1st upper deciduous cheek teeth ('cap'). May cause bitting problems.
Lower wolf tooth - uncommon. May interfere with bit. Advise extraction (local anaesthesia and/or infraorbital nerve block) - can involve extensive elevation of the tooth. Considerable injury can be caused by unqualified personnel. Horses should be vaccinated against tetanus. Use a MUSGRAVE-TYPE ELEVATOR. Attempted extraction can lead to fracture of wolf tooth. Development of bitting problems.