Ch. 14: Lagomorph, Rodent, and Ferret Dentistry Flashcards
What species are included in the order Lagomorpha?
Domestic rabbit, hare, and cottontail
Adult rabbits have how many teeth?
Between 26 and 28 teeth
What does the term rodent mean?
To gnaw
What order is the largest order of the class mammalia?
Order Rodentia
What species are included as pets in the order rodentia?
Rat, mouse, guinea pig, hamster, gerbil, chinchilla, gopher, squirrel, and prairie dog
Most adult rodents have how many teeth?
Between 12 and 22 teeth
What order and family do ferrets belong to?
Order Carnivora and Family Mustelidae
How many teeth do adult ferrets have?
34 teeth
All lagomorphs are herbivores, but some may be _____?
Omnivores
Lagomorphs and rodents have a dental formula that features variations in tooth size and shape. What is this dentition called?
Heterodont dentition
Lagomorphs and rodents have canines, but they are included as an incisor.
True or False?
False; they do not have any canines (They have a diastema (toothless area between the incisors and cheek teeth))
Ferret dentition is similar to a cats dentition.
True or False? And in what ways?
True; they have all 4 kinds of teeth and are also carnivores
How do lagomorph incisors differ from rodent incisors?
Lagomorphs have an extra set of smaller maxillary incisor teeth behind the rostral maxillary incisors
What are the extra maxillary incisors on a lagomorph known as?
Peg teeth
Describe a lagomorph dentition. What is special about them?
The special feature of lagomorph teeth is that they continuously grow and erupt as the teeth undergo normal wear. They have crowns visible intraorally and also reverse crowns submerged below the gingival margin. These teeth never form roots
What is the term for definition that has continuously growing and erupting teeth throughout an animals life?
Aradicular hypsodont teeth aka elodont
What is the term for a tooth that has a true distinction between crown and root and does no longer grow once fully erupted?
Brachyodont teeth; found in humans, cats, and dogs
Guinea pigs and chinchillas have all aradicular hypsodont teeth for both the incisors and the cheek teeth.
True or False?
True
Mice and rats have all brachyodont teeth.
True or False?
False; the incisors are aradicular hypsodont and the cheek teeth are brachyodont teeth
What shape are the maxillary first molar teeth in ferrets?
Hourglass shaped
Ferrets have aradicular hypsodont teeth.
True or False?
False; they are carnivores and have similar teeth to a cat. Cat and ferret teeth are not continuously growing (aradicular) and are all brachyodont teeth
What layers of teeth form the layers of lagomorph and rodent teeth?
They have enamel on the front and lateral sides but only cementum and dentin on the palatal/lingual surfaces
Does cementum and dentin wear faster than enamel?
Yes; this results in a chiseled edge of the teeth in lagomorphs and rodents
The enamel of incisors in most rodents takes on a yellow-orange color. Which rodent doesn’t have a yellow-orange color to its incisors?
The guinea pig
The word apices is the plural form of what word?
Apex
In rats and mice, how far do the roots of the mandibular incisors reach?
They are distal to the roots of the last cheek tooth
In rabbits and chinchillas, how far do the roots of the mandibular incisors reach?
They are located near the mesial surfaces of the first cheek tooth
In lagomorphs and rodents, the highest point of the chisel tip of the maxillar cheek teeth is on the labial side. How are the teeth angled?
Dorsally toward the soft tissue of the hard palate
In lagomorphs and rodents, the chisel point of the mandibular cheek teeth are on what aspect of the tooth?
Lingual side
The maxillary cheek teeth are wider apart from the midline than the mandibular teeth.
True or False?
True; this is called anisognathic
Which species of lagomorph/rodent has the steepest angle of the cheek teeth?
A guinea pig has the steepest angulation while chinchillas have a level occlusal plane
It is thought to believe that the plexus of a tooth allows for continuously growing teeth to move coronally as they grown. This adaptation of hypsodont teeth is thought to explain how ________ allows for continued eruption.
The periodontal ligament (PDL)
What is the dental formula of a rabbit?
2 X (2/1 I, 0/0 C, 3/2 P, 2-3/3 M) = 26-28 total
What is the dental formula of a hare?
2 X (2/1 I, 0/0 C, 3/2 P, 3/3 M) = 28 total
What is the dental formula of a guinea pig and chinchilla?
2 X (1/1 I, 0/0 C, 1/1 P, 3/3 M) = 20 total
What is the dental formula of a degu?
2 X (1/1 I, 0/0 C, 1/1 P, 3/3 M) = 20 total
What is the dental formula of a rat?
2 X (1/1 I, 0/0 C, 0/0 P, 2-3/2-3 M) = 12-16 total
What is the dental formula of a hamster?
2 X (1/1 I, 0/0 C, 0/0 P, 2-3/2-3) = 12-16 total
What is the dental formula of a gerbil?
2 X (1/1 I, 0/0 C, 0/0 P, 3/3 M) = 16 total
What is the dental formula of a squirrel?
2 X (1/1 I, 0/0 C, 1-2/1 P, 3/3 M) = 20-22 total
What is the dental formula of a ferret?
2 X (3/3 I, 1/1 C, 3/3 P, 1/2 M) = 34 total
What forms of anesthesia are available for these animals?
Injectable and inhalant
Due to the odor of the inhalant anesthetic, these animals may do what?
Hold their breath
What IV catheter gauge can be used as an ET tube for smaller rodents (stylet removed)?
12-14 gauge
What instruments are needed for a dental procedure on these animals?
Towel, anesthesia, otoscope, IV catheter, umbilical tape, cotton-tipped applicators, explorers/probes, hand pieces, mouth gags, cheek retractors, burs, files/rasps (floats), tooth cutters, luxators and elevators, extraction forceps, bone substitutes, antibiotic impregnated beads, paper points, calcium hydroxide, and restoratives
What are the most common types of burs used?
Diamond, carbide round, carbide tapered fissure, and white stone points
Rasp instruments cut/file on push and pull strokes. Files cut on what stroke?
On pull stroke
What are burs used for?
Removal of hard tissue
What are luxators and elevators used for?
Used to work circumferentially around a tooth in the PDL space to aid in the tooth’s removal
What tool can also be used for a luxator/elevator function in lagomorphs and rodents?
Hypodermic needles (18-22 gauge) (Curved and bent)
What instrument is used for extraction of cheek teeth?
90-degree angled Halstead mosquito forceps or angled root tip forceps
What are examples of restorative temporary filling materials?
Reinforced zinc oxide-eugenol cements, or glass ionomer
Antibiotic-impregnated beads may be placed for treatment of refractory infections. What are examples of different antibiotics?
Polymethylmethacrylate (releases heat so not recommended) (non absorbable), gentamicin, and calcium phosphate (absorbable)
What is rostral gingivitis in lagomorphs and rodents most commonly caused by?
Trauma caused by rough edges on watering devices, and food bowls
What are the treatments for rostral gingivitis?
Removal of watering/feeding devices. However, if the situation warrants, the lesion can be treated with multiple coats of tincture of myrrh and benzoin or topical antibiotic ointments
Where is periodontitis generally found in lagomorphs & rodents?
In the cheek teeth of animals with brachyodont teeth, such as mice and rats
What species frequently suffer from periodontitis?
Chinchillas
What may be the cause of periodontitis in lagomorphs and rodents?
Tooth elongation and/or tooth resorption in aradicular hypsodont cheek teeth of rabbits, chinchillas, and guinea pigs
What are the treatment options for periodontitis?
Dental cleaning or extractions
Where is enamel hypomineralization/hypoplasia typically seen?
On the incisors
What does enamel hypomineralization/hypoplasia look like?
Chalky white or brown discoloration on the labial surface of the tooth
What are possible causes of enamel hypomineralization/hypoplasia?
Nutritional imbalance, infection, or inflammation that temporarily decreases enamel production
What is the treatment for enamel hypomineralization/hypoplasia?
Correction of the initiating cause
What may result with long-term enamel defects?
Trauma to and subsequent death of ameloblasts
What is the only time an animal with enamel hypomineralization needs to have direct treatment?
If the weakened area of the tooth results in tooth fracture
True caries lesions are generally found in only which teeth of rodents?
Cheek teeth of rodents with brachyodont teeth and occlusal surfaces of the crown but many are found on the root surfaces
Caries in rodents are uncommon.
True or False?
True; but are difficult to find if they are present
Why are caries difficult to detect in rodents?
Because they mostly occur in cheek teeth which are difficult to examine
What is the most common treatment for caries in rodents?
Extraction
Removal of diseased dental structure with a bur and glass ionomer restorations have also been used
What are the two categories of malocclusions in exotic animals?
Traumatic and atraumatic
How is a traumatic malocclusion characterized?
Traumatic injuries to the teeth can result in broken crowns, which may cause overgrowth (elongation) of the opposing tooth because of the lack of normal attrition
What are the treatment options for traumatic malocclusions?
Periodic odontoplasty and exam (determine if pulp is exposed), if pulp is exposed but is still vital, pulp therapy can be performed, if pulp isn’t vital the tooth may need extracted
How is an atraumatic malocclusion characterized?
Caused by hereditary factors or by nutritional factors
Atraumatic malocclusions are found in what three basic forms?
Short maxillary diastema, genetics or nutritional mandibular abnormalities, and improper wear
Diastema definition
A space separating teeth of different function (ex. space between incisors, canines and cheek teeth)
