Equine Dentistry 2 Flashcards
what is periodontal disease
progressive disease in which tissue surrounding affecting teeth is destroyed until eventually teeth may be lost
what is the most common cause of periodontal disease
mechanical impaction of food between and around teeth
what is the cycle of periodontal disease
how does food become impacted between the teeth
diastema allows food to become impacted between teeth
what are diastemas
abnormal spaces between adjacent teeth that should normally be tight in occlusal apposition
what are the two types of diastema
- valve diastema
- open diastema
what are valve diastema
the space between adjacent teeth is wider near the margin of gum than the occlusal surface
creates a one way valve, where food becomes trapped between teeth, but cannot escape
what is an open diastema
the space between adjacent teeth is of equal width from the occlusal surface to the margin of the gum
food can enter and leave the space easily and is less likely to become trapped
what are the most common teeth that are affected by diastema
caudal mandibular cheek teeth
between triadan 09 and 10s
why are diastema painful oral diseases
due to concurrent gingivitis and periodontal disease
what are causes of diastema (4)
- misalignment or overcrowding of teeth due to the presence of supernumerary or dysplastic teeth
- reduction in crown diameter as horses age, resulting in a loss of rostrocaudal compression of a dental arcade
- large dental overgrowths displacing apposing teeth
- dental extraction resulting in diastema formulation due to subsequent dental drift
how are diastema initially treated
removal of all food material from diastema is the single most important aspect of treatment
then dental equilibration should be performed to remove opposing sharp enamel points and excessive transverse ridges
how is diastema treated following the removal of teeth
diastema should be temprorary packed with dental dressings to prevent re-impaction of food while the periodontum heals
how are diastema managed long term
diastema odontoplasty: widening with a motorized burr (3mm groove in the interdental space to reduce occlusal forces from opposing teeth)
when should a diastema odontoplasty
3-4 weeks after initial treatment, especially if initial treatment is ineffective at treating periodontal disease
there is great risk of a iatrogenic damage to pulp horns
how are diastema managed with diet
eliminate or remove consumption of food containing long fibres (hay or haylage) as they become trapped easier
short fibre foods (<5mm) such as chopped grass, alfalfa and some grain
grazing should be encouraged
why do horses on short fibre diets need more frequent floating
short fibres alter the masticatory action of horses, causing them to chew with a more vertical than lateral mandibular action, encouraging cheek teeth enamel overgrowths
what other things can cause periodontal disease
dental calculus (tartar)
what are dental caries
the result of demineralization of calcified (inorganic) dental tissues and eventual destruction of the organic component of teeth
what are the two types of dental caries
- infundibular caries
- peripheral caries
what are infundibular caries
caries of the infundibulae of maxillary cheek teeth
what are peripheral caries
caries of the outside surface of teeth especially of the caudal three cheek teeth
what type of dental carie is this
infundibular
what type of dental carie is this
peripheral carie
what causes infundibular caries
acids formed during bacterial fermentation of impacted food within infundibulae
how does food become trapped in infundibulae
up to 90% of infundibulae are incompletely filled with cementum
areas void of cementum are predisposed to impaction of food, creating an environment where oral bacteria can thrive
what can occur if infundibular caries are left untreated
can progress to midline sagittal fractures of affected tooth and/or potential pulp involvement with secondary apical infection
how are infundibular caries graded
on a scale of 4 based on the degree of tissues involved
what is shown here
infundibular caries (IC)
describe the grades of infundibular caries
0: normal tooth
1: cementum only
2: cementum and underlying enamel affected
3: cementum, enamel and dentine affected
4: secondary dental fracture
what grade of infundibular carie is this
0 normal tooth
what grade of infundibular carie is this
grade 1
cementum only
what grade of infundibular carie is this
grade 2
cementum and underlying enamel affected
what grade of infundibular carie is this
grade 3
cementum, enamel and dentine affected
what grade of infundibular carie is this
grade 4
secondary dental fracture
how are infundibular caries treated in the early stage
they can be monitored if they are grade 1
restoration and filling may be recommended if they start to progress
how are infundibular caries treated once there is dark staining of secondary dentine adjacent to infundibular enamel
the caries have already progressed through the infundibular enamel and restoration and filling should be considered
how are infundibular caries treated if there is a midline sagittal fracture or apical infection
tooth extraction is required
what grade of infundibular carie is shown here
grade 2
dentine surrounding the infundibular enamel is starting to turn brown, indicating it is a good time to pursue treatment in the form of dental restoration
what is the reason for increasing prevalance of peripheral caries
feeding hay high in water soluble carbohydrates, feeding silage and water low in pH have all been found to contributing factors
what can severe cases of peripheral caries lead to
severe cases can lead to periodontal disease or dental fracture
how are peripheral caries graded
4 point based on the severity of lesions
what is shown here
peripheral caries
describe the grading system of peripheral caries
grade 0: normal tooth
grade 1.1: cementum only affected; superficial pitting lesiosn
grade 1.2: cementum only affected, but complete loss in some areas exposing enamel
grade 2: cementum and underlying enamel
grade 3: cementum, enamel and dentine affected
grade 4: secondary dental fracture
what grade of peripheral caries is this
grade 0
normal tooth
what grade of peripheral caries is this
grade 1.1 cementum only affected; superficial pitting lesions
what grade of peripheral caries is this
grade 1.2
cementum only affected, but complete loss in some areas exposing enamel
what grade of peripheral caries is this
grade 2
cementum and underlying enamel affected
what grade of peripheral caries is this
grade 3
cementum, enamel and dentine affected
how are peripheral caries treated
etiology is not fully understood
but its been found that they are reversible if the source of the etiological factor is removed
lavage mouth with a 0.1% chlorohexidine mouthwash daily but long term treatment is expensive and chlorohexidine doesn’t persist in the oral cavity for long
how are peripheral caries prevented
catch them early
thorough examination with a bright light, dental mirror and probe every 6-12 months
assessing body condition score, diet and general health
what is a cheek tooth (CT) apical infection
infection of the apical portion of a CT and peripheral structures (ex. mandibular or maxillary bones, paranasal sinuses)
what are the clinical signs of cheek tooth (CT) apical infection (3)
- facial swelling
- +/- discharging tracts of the mandible or maxillar
- nasal discharge from sinusitis secondary to apical infection of more caudal CT
what is shown here
focal mandibular swelling due to an apical cheek tooth infection
what are the routes of infection for apical infections
most common is anachoresis which is a blood or lymphatic borne bacterial infection of a possibly compromised apical pulp
what are other routes of infection of apical infection
- severe periodontal disease
- pulp exposure on the occlusal surface of the tooth
- following tooth fracture
in what cases where anachoresis the common cause
typically young horses in which there has been recent tooth eruption
how does anachoresis cause apical infections in young horses
apices of erupting teeth may be hyperemic (excess blood within vessels) or inflamed as eruption occurs, especially if there are retained deciduous teeth or overcrowding from adjacent teeth
what makes pulp more susceptible to infection in apical infections
inflamed pulps
how can bacteria in the upper respiratory tract cause apical tooth root infection
anastomoses exist between periodontal vasculature and blood vessels within the maxillary sinuses
bacteria can gain access to periodontal vasculature and inflamed pulps
how are apical infections diagnosed (3)
- findings on clinical examination (ex. facial swelling, draining tracts, nasal discharge)
- intra-oral examination including inspection of pulp horns for pulpar exposure
- radiograph evidence of infection
how can apical infections diagnosed on radiographs
- periapical sclerosis
- periapical halo formation
what is shown here
multiple defects in secondary dentine leading to pulp exposure in a mandibular cheek tooth
causing apical cheek tooth infection
how are apical cheek tooth infections treated in early stages
antibiotics may be effective in some cases if infection is confined to the apex of the affected tooth and pulp cavities remain vital
how are apical cheek tooth infections treated in progression of disease
pulp and calcified dental tissues adjacent to tooth apices will become infected
removal of infected pulp and adjacent infected tissues may be required –> extraction of the affected tooth
but endodontic therapy (root canal) may be performed in select cases
what are the most common causes of incisor fractures
almost always traumatic
why do incisor fractures easily lead to pulp exposure
location of the pulp canal
what is shown here
incisor fracture
fracture of tooth 402, likely with pulp exposure
how are incisor fractures treated (3)
- exposed incisor pulps tolerate inflammation well and can still maintain blood flow –> pulp exposure don’t necessarily lead to pulpar ischemia and tooth loss
the occlusal aspect of the exposed pulp will hopefully seal with tertiary dentine and the remaining tooth can continue to erupt normally
- admin of antibiotics and NSAIDs may be beneficial in the acute stage of fracture
- endodontic therapy (root canal) can be performed to help preserve remaining pulp
how can cheek tooth fractures occur
- external and iatrogenic trauma
- idiopathic (most)
which cheek teeth and the most commonly affected by fractures
triadan 09s are most commonly affected
what is the most common fracture configurations
maxillary buccal slab fracture through the 1st and 2nd pulp chambers, usually only involving the clinical crown
what are other common cheek tooth fracture configurations
- mandibular buccal slab fracture of the 4th and 5th pulp chambers
- midline sagittal fracture through infundibula of maxillary cheek teeth
why are cheek tooth fractures in most cases if possible treated conservatively
whenever possible because it lessens trauma and sequellae of extraction and prevents future overgrowth and drifting of other cheek teeth
what should the aim of extraction be in cases without apical infection be in cheek tooth fractures
in cases without evidence of apical infection, aim at only extracting grossly displaced or loose dental fragments
larger, stable dental fragments should be left to permit possible sealing off of exposed pulp chambers with tertiary dentine
in which cases of cheek tooth fracture is extraction required
midline sagittal fractures
what type of fracture is shown here and how would you treat this
buccal slab fracture of tooth 109
this fracture involves the 1st and 2nd pulp canals of the clinical crown
if there is no evidence of apical infection (lack of clinical signs, no significant abnormalities identified on radiographs) this tooth can be managed conservatively through monitoring
what does EOTRH stand for
equine odontoclastic tooth resorption and hypercementosis
what is EOTRH
resorption of reserve crown, apical region and adjacent alveolar bone of teeth, with proliferation of irregular cementum in the lytic regions
how is EOTRH different to feline odontoclastic resorptive lesions
because hypercementosis is a prominent clinical feature at the time of presentation and diagnosis in many horses
what is the etiology of EOTRH
periodontal inflammation has been suspected to be a trigger
which teeth does EOTRH primarily involve
the incisor and canine teeth
usually affects the corner incisors triadan 03s first, followed by the middle and central incisors triadan 02s and 01s
why is secondary infection common in EOTRH (6)
- gingivitis
- gingival enlargement
- gingival recession
- focal discharging purulent tracts
- increasing tooth mobility
- focal resorptive lesions of the teeth around the gingival margins
what is shown here
EOTRH
what is shown here
EOTRH
what are the clinical signs of EOTRH (6)
- incisor pain reported by owners, reduced ability in grasping apples and carrots
- sensitivity to placing a bit
- head shaking
- ptyalism (hypersalivation)
- head shyness
- periodic inappetence and weight loss
why is oral examination difficult in EOTRH
can be extremely painful
placement and opening an oral speculum can elicit a strong pain response, even under heavy sedation
how is EOTRH diagnosed (8)
- typically identified in older horses (15+ years of age)
- hyperemia (reddening) of the gums
- drainage tracts within gums
- calculus and feed accumulation around the teeth
- gingival recession
- misshapen
- loose, missing and/or fractured teeth
- halitosis (malodorous breath)
what is shown here
classic appearance of ETORH
what is seen on radiographs with ETORH (4)
demonstrate more advance disease than external appearance during an oral exam
- bulbous enlargement of the apical aspect of the involved teeth
- resorptive lesions of the reserve crown
- apex and/or surrounding bone
- widening of periodontal space and tooth fractures
what is shown here
how is EOTRH treated
surgical extraction of clinically affected teeth
horses cope well after incisor extraction (even if all removed)
in some horses, their tongue may hang out of their mouth post-procedure, but this doesn’t appear to have any adverse affects long-term
what is exodontia performed
should not be performed unless determined beyond a doubt which tooth/teeth are problematic and all methods of medical therapy have been exhausted to arrest the disease process and preserve the tooth
what are indications of exodontia (8)
- apical infection
- tooth fracture in which the larger fragment cannot be preserved
- retained deciduous teeth
- loose tooth
- supernumerary, displaced or misaligned tooth causing clinical signs of disease
- impacted tooth
- non-vital tooth secondary to jaw fracture
- overgrowth so severe that is has caused severe soft tissue trauma
how are horses sedated and restrained for exodontia
maintain patient on a constant rate infusion (CRI) of an alpha 2 agonist for the duration of the procedure
prior to starting the CRI, the patient is administered a bolus injection of an alpha 2 agonist in combination with an opioid
what sedatives and what amounts would you give to sedate a horse for exodontia
bolus injection of detomidine (0.02 mg/kg) and butorphanol (0.02-0.05 mg/kg) administered IV followed by a detomidine CRI (0.02mg/kg/hour) IV
what are the nerve blocks of the head used for exodontia (4)
- maxillary
- infraorbital
- mandibular
- mental
where are the maxillary nerve block regions of action (3)
- ipsilateral dental structures of the maxilla
- premaxilla
- paranasal sinuses and nasal cavity
where are the regions of action of the infraoribital block and what is it useful for
same effect as with maxillary nerve block
useful for performing surgery of nose, or maxillary and premaxillary structures
what are the regions of action of the mandibular nerve block
ipsilateral side of mandible and all dental structures
what are the regions of action of the mental nerve block
ipsilateral side of mandible and all dental structures
as well as skin of ipsilateral lip and chin
where is the maxillary nerve block performed
insert a 20 to 22 gauge spinal needle just ventral to the zygomatic process and dorsal to the transverse facial vessels at the level of the caudal third of the eye
needle should be directed at a 90 degree angle to the long axis of head until it hits bone
if blood is seen in needle, it should be redirected as it is in the pterygopalatine fossa, which can cause hematoma formation
if there is no blood –> inject 15-20ml of local anesthetic next to the bone
what is the maxillary nerve block useful for
dental procedures on the maxillary cheek teeth
what are the landmarks for the infraorbital nerve block
to locate the infraorbital foramen, place one finger on the nasomaxillary incisure and one on the rostral aspect of the facial crest
the infraorbital foramen should be palpable depression between these two landmarks
where are the landmarks of the maxillary nerve block
how is an infraorbital nerve block performed
a 1.5 inch 20 to 22 gauge needle is inserted through the skin just rostral to the infraorbital foramen
the needle can be advanced about 2.5cm into the canal and 5 to 10ml of local anesthetic can be deposited in the area
what is infraorbital nerve block useful for
performing surgery on the incisors such as incisor extraction in cases of ETORH
how is a mandibular nerve block
to perform a mandibular nerve block a 6 inch 20 to 22 gauge spinal needle is inserted at the medial ventral aspect of the mandible and advanced dorsally 4-6 inches until it reaches the junction of an imaginary line drawn across occlusal surface of the maxillary arcade and from the lateral canthus of the eye
deposit 15-20ml of local anesthetic in this location
what are the landmarks of mandibular nerve blocks
what is mandibular nerve block useful for
dental procedures on the mandibular cheek teeth
how is mental nerve block performed
block a 1.5 inch 20 to 22 gauge needle is inserted approximately 2.5cm rostral to mental foramen
the needle is directed as far as possible into the mental forament and 5-10ml of local anesthetic
what is the mental nerve block useful for
performing dental procedures on mandibular incisors
what are landmarks of the mental nerve blocks
what are the methods of exodontia (3)
- extraction per os (removal of the tooth orally)
- minimally invasive transbuccal technique
- repulsion with a dental punch or Steinmann pin
how is extraction per os done
systematic stretching and breakdown of the periodontal ligament followed by intra-oral extraction along the eruption pathway of the tooth
why is extraction per os the method of choice
complication rates are lower for the procedure compared to other forms of extraction
what is the first step in extraction per os
after patient has been properly restrained, sedated and the appropriate local nerve blocks performed
gingiva around the tooth is elevated to begin the process of breaking down the periodontum
what is the second step in extraction per os
molar spreaders are placed within the interdental space between teeth to help break down the periodontal ligament
care must be taken to not damage adjacent healthy teeth or disturb the 06 teeth when attempting an 07 extraction and similarly the 11 tooth when attempting a 10 extraction
what is the third step in extraction per os
the next is manipulation of the tooth in the alveolus using forceps
once gentle sustained rotational pressure and intermittent rocking of the tooth has loosened it to a point that frothing blood and ‘squelching’ is heard when extraction of the tooth can be attempted
what is the fourth step in extraction per os
a fulcrum is placed between the forceps and adjacent rostral tooth
gentle firm pressure is applied on the forceps against the fulcrum to extract the tooth in an occlusal direction from the alveolus along the tooth’s eruption pathway
what is the fifth step in extraction per os
once tooth the tooth and alveolus should be carefully inspected to ensure that the tooth has been extracted in its entirety
any remaining fragments of the tooth or fractured alveolar bone should be removed
blue arrow shows a piece of tooth root which fractured off during extraction
what is the sixth step of extraction per os
once empty the alveolus is usually packed with dental impression material to provide hemostasis and prevent food contamination in the early stages of tissue healing
this packing is usually left in place for 3-4 weeks before re-evaluation
how is minimally invasive transbuccal technique performed
used if the clinical crown fractures to a point that forceps cannot be applied to the tooth to attempt oral extraction
a threaded bar is seated into the tooth to be extracted through a buccotomy incision and ventral force is applied to the bar until the tooth is removed
how is tooth extraction through repulsion done
radiographic guided repulsion of an affected tooth can be performed using a steinmann pin or dental punch
when is tooth extraction through repulsion the method of choice
it is the technique of choice if clinical crown fractures to a point that extraction equipment cannot be applied to the tooth and minimally invasive transbuccal technique fails or is not possible
what are post operative complications in tooth extraction through repulsion (6)
- sequestration of alveolar bone
- persistent tooth fragments
- oromaxillary fistula
- chronic sinusitis
- chronic cutaneous draining tracts
- iatrogenic damage to adjacent cheek teeth
do diseased teeth always have to be extracted
no endodontic therapy may be an option to help preserve a diseased tooth (condition dependent)
treatment is aimed at the preservation of teeth affected by pulp exposure or apical infection
why is endodontic therapy difficult in equines (4)
- the complex anatomy of equine pulp
- size of equine cheek teeth
- length of dental arcades
- limited ability of opening a horse’s mouth
make endodontic therapy more challenging when compared to small animals
what is pulpotomy and how is it done
only the infected or exposed portion of pulp is removed
remaining healthy pulp is capped with calcium hydroxide or mineral trioxide aggregate (MTA) to induce production of tertiary dentine over remaining pulp, followed by placement of a restorative composite to seal the canal
what is pulpectomy and how is it done
the entire pulp is removed and the cavity is subsequently restored
when would a pulpotomy be performed
used in cases of acute pulp exposure such as a trauma
the best candidates are those in which treatment is pursued within 48 to 72 hours of injury and damage mostly involves the clinical crown
therefore owners need to be informed of decreased success of treatment if pulp exposure is over an extended (greater than one week) or unknown period of time
what are the cons of pulpotomy
what are pros of pulpotomy
what is the first step of pulpotomy
remove damaged/infected exposed pulp
what is the second step of pulpotomy
to apply a pulp dressing over remaining healthy pulp
what pulp dressings are used in a pulpotomy
pulp dressings such as calcium hydroxide or mineral trioxide aggregate (MTA), have a high anti-microbial effect due to a high pH and also act as a stimulant for tertiary dentine production to cover the exposed pulp
what is the third step of a pulpotomy
seal the top of the pulp canal with a composite resin material to restore the pulp
when would a pulpectomy be performed
when devitalized tissue is observed within the pulp canal but surrounding dentine is still intact and extensive periapical osteolysis cannot be detected on radiographs or CT
how effective are pulpectomies
questionable
pulp canal shape and continuous occlusal wear inhibit long-term success of root canal therapy
also depending on the location of the tooth, there may be limited access to the affected pulp (ex. caudal cheek teeth) making treatment difficult
what are the pros of pulpectomy
tooth remains in occlusal wear
what are the cons of pulpectomy
what is the first step in a pulpectomy
- involved pulp canal is cleaned out of diseased tissue and feed using endodontic files
radiographs are taken during the procedure to determine if the full length of the pulp cavity has been cleaned
what is the second step in pulpectomy
- after cleaning, pulp cavity is flushed with sterile saline and antiseptic solution and calcium hydroxide is applied to dissolve any non-vital pulp and remnants of feed
what is the third step of pulpectomy
- the cleaned pulp cavity is sealed in two layers of different dental filling materials. First is a bluck filling material to fill the majority of the pulp canal. The top of the pulp cavity is then sealed with a composite resin to act as an occlusal seal
