export_chapter 20 exodontia Flashcards
When is an intraoral approach for equine cheek tooth extraction not possible?
- when crown of tooth can’t be grasped such as: Reserve crown fractured, clinical crown brittle dt caries, when reserve crown so large from cemental hyperplasia or dental tumor cant traverse the alveolua
What are two extraoral approaches to equine tooth extraction?
- repulsing into oral cavity with mallet and punch
- buccotomy after removing lateral plate of alveolar bone
Are retained deciduous incisors in a horse a problem?
Where are they usually located?
- cosmetic only
- rostral to adult
Are supernumerary incisor teeth usually a problem in horses?
What happens to gap in teeth when incisor tooth extracted?
- cosmetic only
- teeth realign and gap dissapears
Are supernumerary incisors difficult or easy to extract in horse?
Why?
- difficult
- long reserve crown and close proximity to other teeth.
What should be done for an avulsed equine incisor?
Avulsed equine incisor with some gingival attachments?
- extraction
- debridement and reduction of fracture w/ immobilization
What are 4 indications for extracting equine canine teeth?
- severe periostitis from bit injuries
- fractured tooth or fracture alveolus
- resorptive lesions
- hypercementosis syndrome
Why is extracting equine canine teeth not recommended unless absolutely necessary?
- tongue will spill out which can affect performance if show horse
Why are equine canine teeth extractions difficult?
What nerve can be damaged?
- long curved alveolus
- mandibular alveolar nerve
What tooth is the equine wolf tooth?
Are they more common in mandible or maxilla?
- first premolar
- maxilla (rare in mandible)
What percentage of horses have maxillary wolf teeth?
Are they always bilateral?
When do they erupt?
- 40-80%
- often only one
- 6 and 18 months
Where are wolf teeth usually located?
- variable: rostral to second PM, buccal, palatal or close to canine
- subgingival
What is problem with subgingival wolf tooth?
- occasionally associated with gingival ulceration, discomfort when contacted by bit
Why have wolf teeth traditionally been extracted?
Is this necessary?
- large, molarized, aberrantly placed
- entrapment of buccal mucosal fold of commisure of lips–> bitting problems
- difficulty in floating second PM
- not sure about 2 and 3
What has traditionally been used to extract wolf teeth?
What works better?
- burgess elevator
- small curved periodontal elevator (more precise and effective)
Should mandibular wolf teeth be extracted?
- probably-cause bit discomfort
When should deciduous teeth be removed?
When should they not be removed? Why not?
- periodontitis from entrapped food
- painful remnant in interproximal space
- if gingival attachments intact b/c underlying permanent tooth may not be doen forming
What are complications associated with repulsion of equine cheek teeth?
What are complications of extraction through buccotomy?
What is preferred technique? Why?
- dental or osseous sequesta
- oro-antral fistula
- Damage to branches of the dorsal buccal nerve or the parotid salivary duct.
- per os. cheaper, probably easier
Why is extraction per os often cheaper than repulsion or buccotomy?
- usually can be done with standing sedation
Which teeth are the most difficult to extract in the horse?
- caudal (10s and 11s)
- young horses with long reserve crowns and little period dz
Do all fractured teeth need to be extracted?
- no if no evidence of apical infection
Which tooth is the most commonly fractured tooth in the horse?
What is typical configuration of fractured tooth in the horse?
- maxillary 09
- parasagital lateral slab that is easily removed
- larger non displaced parent fragment that doesn’t need to be extracted if exposed pulps not sealed off and no apical infection present
What is possible problem with a diseased maxillary tooth?
How is this treated?
- inspisated exudate in sinus
- osteoplastic flap to remove exudate
Who first described per os extraction in horse?
O’Connor 1942, Guard 1951
Between which teeth should spreaders be used gently?
- 06 and 07 when extracting 07
- 10 and 11 when extracting 10
How long do you keep a molar separator in place?
- 5 minutes each side
Which equine cheek teeth are are narrowest?
- mandibular
How are equine molar extractors used?
- placed on tooth being careful not to overlap teeth
- Handles fixed with rubber bandage or locking mechanism
- moved in slow, low amplitude, horizontal, to and fro oscillation along longitudinal axis of tooth (check after first few to make sure hasn’t slipped)
- gradually increase amplitude as tooth loosens
- when squelch heard, apply fulcrum, advance caudally - apply firm steady pressure
What can cause teeth to fracture during extraction?
- torsional movement along axis of extractor handles
- excessive force, or too wide of an arc
How long does it take to extract a cheek tooth?
- an hour or more
What is done after a cheek tooth is extracted?
- curette any fragments with an angled currette
- pack with polysiloxane putty, dental wax, metronidazole paste (packing extruded as tooth heals)
What happens if the tooth breaks during extraction and leaves an apical fragment?
- try to elevate per os using long, right-angled elevators and extracted with long right angled elevators
- if can’t be extracted per os, repulse using a special root fragment punch or a steinman pin
- extract via buccotomy
How do you extract a root fragment via osteotomy?
- create 4 mm osteotomy over retained fragment with Steinman pin or drill bit
- repulse fragment with Steinman pin or root fragment punch
- clean alveolus with spoon currette, then irrigate
- leave skin incision to heal by second intention
How do you extract a root fragment via buccotomy?
What are risks with this method?
- make stab incision at level of alveolus, insert elevator, elevate, extract per os
- can damage facial nerve or parotid salivary duct or could innoculate subQ tissues with bacteria
What should be done if parasinuses are infected?
What if alveolus communicates with parasinuses?
- debride through osteoplastic maxillary or frontonasal flap or trephine hole or lavage through catheter and small trephine hole
- seal off with polysiloxane putty or PMM bone cement
If plug is inserted into alveolus after extraction where should it be?
What is purpose of plug?
- coronal 1/3, flush with gingival margin
- to prevent food impaction
What are potential complications of per os extraction?
- fracture of tooth w/ retained fragment
- damage to healthy adjacent teeth
- fractured jaw
- feed impaction
- oroantral fistula
- alveolar bone sequestra dt microfracture
How are oro-antral or oronasal fistulas treated?
- debride dental or osseus fragments
- remove food and exudate
- seal the oral aspect with an acrylic plug, mucoperiosteal flap, transposted muscle belly
What are the two surgical extraction techniques in the horse?
- repulsion
- buccal flap and partial alveolar osteotomy
Why is repulsion not good way to extract teeth?
- high incidence of complications
What should be done before extracting a tooth by repulsions?
- Use forceps per os to disrupt ligament as much as possible
How is tooth extracted through repulsion in the horse?
- expose apex through trephination, drill bit, bone saw or chisel/osteotome OR frontonasal or maxillary osteoplastic flap if completely within maxillary sinuses 09-11s
How do you find the root apex for repulsion of 2nd or 3rd premolars?
How do you find the root apex for repulsion of 08-11?
What is best way to find root apex?
- center of clinical crown
- caudal contact of tooth if 9
- radiographs
Is anesthesia or sedation used for repulsion of horse teeth?
- anesthesia
When performing osteotomy for repulsion, what teeth may result in damage to infraorbital n or facial artery?
What structures may need to be reflected for 309, 409?
- 06-08
- facial a and v and parotid salivary duct
Which teeth require an osteoplastic flap through the paranasal sinuses?
- 09-11
What imaginary line is used to find level of osteotomy?
Ventral or dorsal to this line?
If horse is less than 8 years old?
If horse is old where should dorsal aspect of a maxillary osteotomy be?
If horse is young where should ventral aspect of osteotomy be?
- course of the nasolacrimal duct–medial canthus of eye to infraorbital foramen
- ventral
- close to the line
- close to the facial crest
- at border of mandible
After making incision or flap in skin, what are next steps in repulsing and equine tooth?
- remove periosteum
- create osteotomy 1.5 x 2 cm trephine or 0.95-2.7 cm drill
- expose apex with bone curette or rongeur
- transect apical end of tooth
- seat punch
Where should trephine hole be created for Maxillary M1?
- M2?
- paranasal sinus midway between rostral end of facial crest and point on crest at level of medial canthus, 1 cm ventral to line btween io foramen and medial canthus
- paranasal sinus rostroventral to ventral orbital rim (varies with age)
What is the triple trephine technique?
- one hole dorsomedial to the medial canthus of eye to place punch on apex of tooth
- second hole ventrorostral to medial cnathus to guide punch onto apex and allow post op explore of alveolus
- third hole at agnle formed by orbit and faical crest to place catheter into sinus for post op lavage.
How can maxillary sinus of old horses be accessed?
What is disadvantage?
- maxillary or frontonasal flap
- have to reopen to monitor healing or to currette alveolus (vs. unsutured trephine hole)
How is apex of M3 exposed?
What kind of punch must be used?
Why?
- trephine hole in frontal bone or frontonasal osteoplastic flap
- offset
- root is below orbit and caudally curved
How is mandibular 10 or 11 removed?
- incise ventral aponeurosis of masseter, reflect masseter
How should punch be aligned and what is problem if unable to do this?
- along axis of tooth
- if oriented obliquely need more force and more likely to result in sequestra
Should a tooth be transversely sectioned as it is repulsed?
- No-should not be necessary
How should alveolus be treated after repulsion of a equine tooth?
- coronal 1/3 plugged
- if left unsutured rolled gauze impregnated with dilute povidine-iodine packed into the apical aspect prior to plugging the coronal apect then gauze gradually remove
How do you keep a maxillary PM2 plug or plug of two adjacent teeth in place?
- mesh with wire
How do you lavage paranasal sinuses after repulsion of maxillary 10 or 11?
How does fluid exit?
How often should this be done?
- trephine hole into conchofrontal or caudal maxillary sinus. Trephine hole into conchofrontal sinus 2-3 cm medial to madial canthus, trephine hole into caudal maxillary sinus through straight incsion 1.5 cm ventral to ventral lid of eye
- insert foley catheter, flush with isotonic saline or povidone-iodine
- through nasal cavity via nasomaxillary aperture
- 1-7 days
What are complications associated with extracting a cheek tooth by repulsion?
What is most common?
What increases risk?
- damage to other teeth, io or mandibular nerve, palatine bone, medial or lateral lamina of mandible or maxilla
- early loss of plug->contaminated alveolus or paranasal sinus
- oro antral fistula
- damage to nasolacrimal duct, parotid salivary duct, IO n, palatine a
- chronic draining tract from sequestra
- most common is sequestra
- more caudal, more complications
What tooth cannot be removed by buccotomy?
- 11s
Does buccotomy require anesthesia?
What are advantages of buccotomy?
- yes
- more controlled disruption of PDL
Which teeth are accessed by vertical buccotomy incision?
Horizontal?
- 09, 10
- 06-08
Where is incision for horizontal buccotomy made?
Where is vertical buccotomy incision made?
- curvilinear skin incision centered over the tooth at level of tooth’s gingival reflection in the buccal cleft
- parallel to the linguofacial artery and vein
Why are mandibular first and second molar teeth accessed with vertical incision?
- to avoid the linguofacial artery and vein and the parotid salivary duct
What nerves can be damaged when removing maxillary teeth via buccotomy?
mandibular?
- dorsal buccal branch of facial nerve
- ventral buccal branch of facial nerve
Where is maxillary buccotomy incision made with respect to parotid papilla?
Where is mandibular buccotomy incision made with respect to parotid papilla?
- what is landmark for the parotid papilla?
- dorsal
- ventral
- rostral aspect of 108/208
What structures are encountered during deep dissection of tissue for buccotomy?
- ventral buccal glands, buccal venous plexus
What vessels make up the buccal venous plexus?
- labialis communis, labialis maxillaris, labialis madinulars vv,
What are the steps for a buccotomy once the oral mucousa is incised?
- gingival flap
- incise periosoteum and reflect
- incise buccal alveolar bone parallel to long axis of tooth with oscillating saw, surgical fissure burr or sharp chisel, remove plate
- elevate (split tooth longitudinally or transect transversely first)
- pack alveolus with gauze and put through adjacent stab incision
- suture flap or leave open
- close buccotomy in 3 layers
How much lateral wall is removed in buccotomy procedure to expose apical end of tooth?
- 2/3
What are complications of horizontal or vertical buccotomy extractions?
How common are complications?
- damage to ventral or dorsal buccal nerve or parotid salivary duct
- temporary facial nerve paralysis from trauma to dorsal buccal branch of facial nerve
- partial dehiscense
- one study only 1 out of 44 needed second surgery
