Flashcards in CAL - Small animal dentistry Deck (118):
How does the root apex differ between species?
Humans - single foramen. Multiple canal delta arrangement (cats and dogs) or remain open (herbivores = in some the apex closes eventually, in others it remains open throughout life).
What bone types do the alveolar processes comprise?
alveolar bone, trabecular bone and compact bone
What is the cribriform plate?
the densest bone of alveolar process - it lines the alveolus
What is a good radiographic sign of periodontal health?
uninterrupted lamina dura
When is enamel made?
by ameloblasts before eruption of tooth
What is the second hardest tissue in the body after enamel?
What is the main structure of dentine?
dentinal tubule (this extends from the external surface to the pulp) 3 types - primary, secondary and tertiary
Where is cementum? What is is supplied by?
covers the enamel free roots. provides point of attachment for the periodontal ligament. remodels continuously. nourished from vessels within the periodontal ligament.
What are the taut collagen fibre bundles in the periodontal ligament (PL) called? What are the fibre types?
sharpey's fibres - these are inserted into the cementum and alveolar bone. 3 distinct fibres - gingival, trans-septal and alveolodental
What is found within the PL?
blood vessels - evenly distributed. nerves (heat, cold, pain, pressure and proprioception in some species)
Where is the living tissue in the tooth found?
pulp chambers and root canals - comprises CT, nn, lymph v, BVs, collagen and undifferentiated reserve mesenchymal cells (e.g. odontoblasts)
What lines the pulp cavity?
odontoblasts (these branch into the dentine tubules)
What are the dangers to pulp? 4
physical trauma, accidental over-heating, pulp exposure after tooth fracture, loss of blood supply following trauma
What is the mucogingival junction?
junction between soft, fleshy mucous membrane of oral cavity and tough, collagen-rich gingiva.
Why might the gingiva change height? 3
hyperplasia, recession or attachment loss
How often does the gingival sulcus renew its epithelium?
every 4-6 day s(i.e. rapid) verus 6-12 days for oral epitheloum
What bathes the sulcus?
crevicular fluid - contains many elements of immunity
Normal depth of gingival sulcus - cats and dogs?
cats = 0.5mm to 1mm
dogs = 1-3mm
What often happens to the sulcus in active disease and attachment loss?
deepens, separates from root suface, tissues become infiltrated with primary and secondary immune response.
How does the gingival tissue attach to tooth?
via junctional epithelium (JE) using hemidesmosomes
Is the cemento-enamel junction (CEJ) normally visible?
not normally visible i health. if present, it indicates the recession of the attachments of the tooth and is highly significant.
What is interdental papilla?
the gingival peak between closely adjacent teeth - prevents food impaction.
What isthe col?
an indentation of the interdental papilla when viewed from coronal aspect. not keratinised
When do incisors commonly become mobile?
when affected by periodontal disease
effect of losing the lower canines
weakens rostral mandibles significantly, allows tongue to fall out of mouth, can lead to excessive drying and or trauma to tongue
what does loss of upper canines in cats cause?
upper lip to fall inwards. lower canine can then occlude lateral to the displaced lip and cause excoriation and punctures.
What is a pinking shear
when looked at from the side, the PM should show this as the upper PM points into the interdental space on lower jaw and vice versa.
What teeth do dental caries affect?
molars - 7% incidence in mature dogs
Which species is the triadan system based on?
Pig - 11 teeth in each quadrant so 44 total
Which quadrant is number 2?
left upper permanent
Which quadrant is number 7?
left lower deciduous
What are the 4 landmark teeth?
-central incisor is always 01
-canines are always 04
-last PM is always 08
-first molar is always 09
What are the carnassial teeth?
Upper - last premolars (108 and 208)
Lower - first molars (309 and 409)
How can the patient be positioned?
lateral (preferred usually) or dorsal recumbency
How do you prevent aspiration?
cuffed endotracheal tube and pharyngeal pack
Why is dorsal recumbency good?
superior visualisation of all aspects of teeth, especially maxillary
What should you be aware of when using gags?
over-opening the mouth and straining the TMJs over a long period of time
What is the extraction probe used for?
The periodontal probe is used subgingivally to explore the sulcus, mainly to determine pocket depth, but also for locating the subgingival calculus and other problems. The sharp opposite end (shepherd’s hook) is used o n the crowns, to distinguish caries from reparative dentine or staining, to determine presence of pulp exposure and, possibly, for other supragingival lesions.
Use of periosteal elevators
mainly used to lift full thickness soft tissue flaps
Use of supragingival scaler
removing supragingival calculus only. It is never used subgingivally.
Use - subgingival curette
To use subgingivally, push the blade to the floor of the sulcus and engage the enamel or cement surface and
clean off debris with a sharp, but sustained, up -stroke
How should you select an oral cavity suture kit?
the oral cavity has limited operating space, especially cats. needle size and type also need to reflect the tough tissues of the oral cavity. curved needles most useful in confined spaces
What are the most common materials use in the mouth? 5
monocryl, vicryl, vicryl rapide, PDS11, chromic catgut
Which elevator is less likely to slip?
a winged elevator
What should the modified pen grip protect you against?
carpal tunnel syndrome (CTS)
What can you use to clean dental instruments?
care (avoid chipped or broken tips), soak in solution containing glutaraldehyde or formaldehyde. the best moethod is using an ultrasonic bath followed by autoclave (124 degrees) but sharpen before autoclaving
Why should you replace surgical masks?
they have a limited period of effectiveness.
what can you use a dental mirror for?
checking the reverse side of the teeth for lesions and calculus, also doubles as a useful lip retractor or tongue depressor
What are ultrasonic scalers used for? what is their ultrasonic range?
to remove calculus rapidly from the tooth surface. range is 20-45kHz. Most of the scaling power is available at the tip, which is cooled with a jet of water.
How often should you keep the tip of a scaler moving over the teeth? Why?
because the heat generated at the tip. don't spend more than 10 seconds on any individual tooth and never press harder than one ounce of pressure. best practice is to select a group of 3 or 4 teeth scale them in sequnce.
Can you perform subgingival work with a scaler?
yes if you use the correct type of insert (the standard beavertail shape cannot be used for this purpose)
What do sonic scalers do?
remove calculus from the surface of the tooth.
Advantages - sonic scalers
create less heat at the scaling tip than an ultrasonic machine which reduces the risk of iatrogenic heat damage. avoid need to purchase a separate ultrasonic scaler unit.
Disadvantages - sonic scalers
slow (vs ultrasonic scalers), noisy, erroneously thought to be cheap to buy.
What do rotosonic scalers do?
remove calculus from the tooth by both high-speed rotation and ultrasonic vibration
Why can rotosonic scalers be dangerous?
severe damage possible to the enamel and dentine if not used carefully
What is air polishing?
an alternative, non-contact method of polishing teeth compared to polishing cup and paste. it uses medical-grade sodium bicarbonate and water in a jet of compressed air to sandblast the surface of the enamel smooth.
Advantages - air polishing
no physical contact (no risk of thermal injury), ideally suited or teeth separated by wide diastemata, good for cats were teeth are so small that standard cups can damage the gingiva, efficient at removing stains from teeth.
Disadvantages - air polishing
cannot point spray directly into sulcus therefore subgingival polishing not recommended. it generates aerosol of micro-organisms and powder so personal protection is very important.
What can an electric micromotor dental unit do? 2
polish or cut. advantages = relatively shceap, generally small, compact and mobile
Disadvantages - electric micromotor dental unit
rather slow, burs wlak off teeth during cutting due to slow speed, hand pieces vibrate and heat up after a few minutes, high torque which is bad when drilling but not polishing
What do air driven high speed dental units allow?
cutting, polishing and other advanced function.
GOOD = very reliable, versatile, sophisticated, greater job satisfaction
BAD = relatively high initial cost
COMPONENTS - high speed hand piece, air/water syringe, slow speed handpiece, compressor
What is a dental bur used for? What are they made of?
cutting hard tissues -tooth or bone. Made of steel, stainless steel, tungsten carbide and diamond grit. All burs have a shank and a head.
is the dental specialty concerned with the study and treatment of the dental pulp.
Indications for extraction - 6
mobile teeth, teeth crowding, retained deciduous teeth, teeth in the line of a fracture, teeth destroyed by disease, endodontically diseased teeth
a branch of dentistry that deals with the extraction of teeth.
What are Fahrenkrug elevators useful for?
Extraction of deciduous canine teeth
What size should the blade be?
approx one third the size of the circumference of the root to be removed.
What size scalpel blade do you use to make the gingival incision?
number 11 or 15
What will happen when you sever the periodontal ligament?
Haemorrhage - the hydraulic pressue will help push the tooth out of the alveolus
How do you clear the sockets of debris?
flush with saline. An alveoloplasty is the smoothing of the bone crest and is necessary to allow the soft tissues to be sutured over the site without tension/ Reduce any bony abnormalitis witha round bur and water irrigation or a bone file. If necessary, fill the alveolus with an osseopromotive material to maintain the ridge.
How should you suture the gingival tissues?
absorbable single interrupted sutures, spaced no more than 1.5mm apart.
Advantages of suturing the gingival tissue - 5
prevents contamination of the site by food and other debris, prevents loss of blood clot leading to post-op haemorrhage, protects bone and other underlying tissuess, creates gingival collars for adjacent teeth unaffected by the disease process, improves patient comfort.
Risk of suturing the gingival tissue
trapping contaminated tissue under flap
When do you need to create a flap during tooth extraction?
When the tooth has multiple roots. this will allow visualisation of alveolar bone and root furcation for splittng
+ and - of envelope flap = ?
+ stand less chance of severing important BVs
- it requires disruption of the gingiva of several adjacent teeth
Why is broad base important?
it means there is a broader vascular base
How do you expose the furcation?
remove a semi-circle of bone from buccal alveolar crest with a small round bur
How do you split the furcation?
split tooth into two/three single roots with a taper fissure bur working FROM the furcation TOWARDS the crown and NOT vice versa to ensure the tooth splits evenly. Remove 1-2mm labial alveolar bony crest circumferentially around the two main roots. Make a smalll horizzontal cut intoo the tooth roots caudally and rostrally at the alveolar crest.
What does an osseopromotive material do?
advantages in maintaining the blood clot and encouraging new bone growth to maintain the alveolar bony ridge. Under optimum conditions, the alveolus will fill with new bone withing 6 weeks. Without the graft, the socket is colonised by a blood clot, followed by fibroblasts.
What will tension in a sutured flap cause?
What are cuspid teeth? Why are they problematic?
= canine teeth. problem due to their size and curvature
How may an Oronasal fistula (ONF) be caused?
robust use of luxators will cause the apex of the tooth to be forced into the nasal cavity causing an ONF
What might over-robust elevation of the lower canines cause?
symphyseal or horizontal ramus fracture of the mandible.
How big are the roots of upper canines and where is the apex?
approx 60-70% total tooth length is root and apex is usually located above PM 2
The depressions between the ridges of bone formed by roots in the alveolar process on the mandible or the premaxilla and maxilla.
Define lamina dura
The dense cortical bone forming the wall of the alveolus next to the tooth. It appears on a radiograph as a white line next to the dark line of the periodontal ligament.
How do you extract an upper canine if it is mobile?
as for a single tooth but take care not to rotate the root apex into the nasal cavity
How do you check for a pre-existing ONF?
flush the alveolus (of upper canine) with saline and checking for liquid flow from the ipsilateral nostril. IF there is good integrity of the alveolar floor, pack with alloplastic material (e.g. Boneglass). It is common to find an ONF at this stage and if you do, DONT fill with Boneglass.
What should you bear in mind about the root of a lower canine?
that the root is bulbous with a greater width than the crown.
What is the rule of dental succession?
Never have two teeth of the same type in the same place at the same time.
IF you are unsure if an animal has retained deciduous teeth, what should you do?
DONT remove any teeth - litigation commonly follows if mistakes are made. Seek advice.
Where are permanent teeth in relation to deciduous teeth? Exceptions?
Permanent teeth are normally lingual or palatal to their deciduous precursors. The exceptions are the
permanent maxillary canine, which is rostral, and the permanent maxillary premolar 4, which is buccal
and distal to the last deciduous tooth.
Why should you be especially careful when removing deciduous teeth?
They are easily fractured
and remaining root tips may still deflect the erupting permanent tooth into a malocclusion. Avoid over-vigorous deep elevation - this may cause permanent damage to the developing
enamel on the crown of the succeeding permanent tooth. Be aware of the position of the permanent tooth.
How do you extract cat teeth in relation to dogs?
The extraction techniques for cat teeth in the main follow those of dog teeth. Exceptions exist where
subgingival resorptive lesions (FORL’s or “neck lesions”) damage teeth roots. Teeth affected by FORL’s rarely
have a morphologically intact root for extraction. In these circumstances, amputation of the crown and the root
tissue, immediately below the alveolar bone crest, may be permissible.
Another name for neck lesions = ?
subgingival resorptive lesions. these can partially or wholly destroy teeth.
How might you remove a tooth with a neck lesion?
In this circumstance there may not be a complete root to luxate and complete root removal may not be possible. Alternative techniques exist in the literature for these teeth. Some texts des cribe the amputation of the crown and partial atomisation of roots with a bur. This may be suitable in some circumstances where root destruction and/or ankylosis prevents conventional elevation of the root. A slow speed handpiece should never be used for this atomisation as the high torque, slow speed and lack of irrigation will cause necrosis and sequestration of the alveolar bone.In normal circumstances, there is no substitute for careful elevation and removal of the whole root.
Where may an ONF occur?
This complication can occur in any location from the upper canines, caudally.
What is an oro-antral fistula?
Oro -antral refers to a communication between the oral cavity and the maxillary sinus – most common following
upper premolar 4 (carnassial) extraction.
When are ONF or oro-antral fistulas most likely to occur?
They are most common where the bone plates are thinnest – either naturally or after periodontal or metabolic disease.
What are the main reasons for dehisence of flaps? 3
The main reasons for dehiscence of flaps are:
· Chronic osteitis at site from local infection
· Tension on sutures
· Suture lines unsupported and located over a void.
How much soft tissue contraction should you expect during healing?
Why do you get flap tension?
usually due to poor flap design
Why do many ONF's stay open?
Many ONF's stay open due to the pressure differential between the nasal and oral cavities. After six weeks, if
the ONF is large enough to cause chronic rhinitis and sneezing, closure by flap surgery is indicated.
Where may you get haemorrhage from? 2
from bone or soft tissue
How can you deal with a fractured root tip? Alternatives? 4
must be removed- delineate the remaining root tissue with a small (e.g. Number ½ round) bur and “walk” down the outside of the root, circumferentially, to isolate it from the bone. Use a root tip pick or fine blade luxator to loosen and remove root tip.
· Bur away part of the bone plate to remove root tip
· Atomise root tip with high speed round bur with water irrigatio n - so called ”Dental Pulverisation”
· Leave the root tip for a few weeks before a further attempt is made to remove it – but follow the guidelines
Which diseases may increase the risk of a maxillary or mandibular fracture? 2
secondary hyperparathyroidism and extensive bone loss due to advanced periodontal disease.
List some examples of iatrogenic damage to deep structures
-infraorbital nerve and artery dorsal to UPM4
-inferior dental alveolar nn and attendant BVs ventral to all lower PM and M
-orbit and globe of eye deep to UM1/2
-hypoglossal nn and artery lingual to M1,2,3
How long may analgesia be needed post-op?
48-72 with major extractions post-op. In severe cases, full agonist or partial agonist opiods may require hospitalisation. NSAIDs can be used in addition. Carprofen and meloxicam on day of surgery.
Which organs need to be healthy to use NSAIDs?
kidneys and liver
When can you use ketoprofen?
NOT on the day of surgery (for dogs or cats). use for UP TO 3 days.
What are the two main sensory nn that supply the teeth and jaws?
infra-orbital and inferior mandibular nn. pre-op regional nn blocks on this assits comfort and reduces need for powerful anaesthesis post-op.
What can you use for regional oral nn blocks?
mepivicaine or preferably bupivicaine
Where do you nerve block the infraorbital nn?
The infraorbital nerve is sensory to the maxillary teeth via the caudal, middle and rostral superior alveolar
nerves. These branches leave the main nerve trunk before it leaves the infraorbital canal. For a regional block
to be successful the needle must enter the canal by 20-32mm, depending on dog size, before depositing the
local anaesthetic. Once the nerve leaves the infraorbital canal it is sensory only to the upper lip and nose
Where do you nn block the inferior alveolar nn? What do you need to be careful of?
The inferior alveolar nerve innervates the mandibular teeth. All the branches to the teeth have left the main
trunk before it emerges from the three mental foramina. The only effective method is to deposit local
anaesthetic at the foramen on the lingual aspect of the caudal mandible where the nerve enters the bone. This
requires either an intra-oral approach or a ventral approach. The intra-oral approach is preferred as it allows
greater accuracy. The mandibular foramen is half way along a line between the crown on the last (third) molar
and the angle of the mandible. Position the needle at the opening of the foramen and deposit the dose whilst
securing the needle with a finger. The operator must be aware of two other branches of the mandibular nerve
close to the injection site – lingual and myelohyoid. Accidental anaesthesia of these nerves will desensitise the tongue – possibly with disastrous consequences.
What might you need to give to provide a practical and necessary level of hygeine in the healing period?
Antibiotics should be used for an appropriate length of time depending on the procedure and pre-existing
pathology. This could mean a period of up to three weeks in some cases. This, combined with a palatable
chlorhexi dine mouthwash (CHX Guard or CHX Guard LA: Virbac) is appropriate.
How should the diet be altered after an extraction? 3
-soft food for the first 2-5 days
-hard chews and tugs avoided for 14 days
-muzzling may be required to prevent traumatic disruption of any flaps.