Advanced veterinary dental techniques (Orthodontics/malocclusion) Flashcards
What is orthodontics?
Orthodontics is the branch of dentistry dealing with incorrectly positioned teeth
or jaws, resulting in abnormal occlusion (malocclusion).
Occlusion is best checked
before?
Endotracheal intubation, with the mouth fully closed and lips parted.
Photographs are used to document?
Pre-, peri- and post-treatment appearance.
They are useful in allowing both client and vet to chart treatment progress.
Sequelae of untreated malocclusions include?
Problems with mastication, soft
tissue trauma and pain, periodontal disease, oronasal fistula formation, dental
attrition.
What are the ethical considerations for orthodontics in animals?
Any orthodontic treatment should be carried out to minimise/remove pain and
allow normal function. Orthodontics in animals should never be performed for
cosmetic reasons. Furthermore, where orthodontic correction is carried out, it
can effectively conceal a genetic defect, and so treated animals should be
neutered. It is never ethical to correct abnormally positioned teeth for the
purposes of showing. The Kennel Club/Governing Council of the Cat Fancy
should be notified of any modification. The owner of any show animal should
sign document confirming they will notify the regulatory body.
What is the biological basis of tooth movement?
Bone responds readily to changes in pressure applied to it, by either resorbing
existing bone or forming new bone, according to Wolff’s law. Forces applied to
teeth will transmit to bone, and induce remodelling of the alveolus position.
Teeth can be moved by forces applied to them, which may be from an
orthodontic construct or from the lips and tongue. Macroglossia can result in the
labial tipping of mandibular teeth. Tight-lip syndrome seen in Shar Peis can
result in the lingual tipping of teeth. Forces on teeth can be intermittent (for
instance ball therapy, inclined bite planes) or continuous (elastic chains). Light
forces are best used in order to move teeth. If the force is too heavy it can
produce periodontal ligament fibre necrosis resulting in undermining resorption
of the root. During orthodontic tooth movements, there will be a pressure side
and tension side to the tooth. Where pressure is applied to the alveolar bone, it
will be resorbed, and where there is tension, bone will be deposited.
What are the rules of anchorage for a mesioverted maxillary canine?
When elastic chains are used to tip a mesioverted maxillary canine
tooth, the anchorage is provided by the maxillary 4th pre-molar and 1st molar as
an anchorage unit. The overall surface area of periodontal ligament fibres in the
anchor should be larger than the PDL surface area of the canine to be moved.
What is Interceptive orthodontics?
This can be described as the extraction or recontouring of deciduous or
permanent teeth.
What is Corrective orthodontics?
This describes the active treatment to restore dental occlusion to normal,
followed by a retention phase. Derangements of normal occlusion may be seen
in the deciduous or permanent dentition. The goal of treatment is to restore a
pain-free and functional occlusion.
Malocclusions may be due to either?
Dental (abnormal positioning of one or
more teeth) or skeletal (abnormal length of one jaw) in origin.
Unless there is a
known trauamatic incident to contribute to a skeletal malocclusion they are
considered to be genetic in origin. Affected animals should therefore be?
Neutered and the client counselled thoroughly before treatment.
Why is timing of treatment important?
Malocclusions should be identified as soon as possible, eirther in the
puppy/kitten, or as permenent dentition is erupting. Young bone is less resistant
to tooth movement due to the animal already being in a growth phase.
What is a class 1 malocclusion?
Class 1 malocclusion (neutroclusion)
Normal rostrocaudal relationship of maxillary and mandibular arches, but incorrect position of one of more teeth.
What is an example of a class 1 malocclusion and how can it be treated?
Mesioversion of the maxillary canine teeth (lance canines)
often seen in Shetland Sheepdogs. This causes pain due to toothtooth contact, allows plaque accumulation and therefore periodontal
disease between the canine and lateral incisor, and causes
buccoversion of the mandibular canine tooth (as there is no room for
it between the maxillary canine and incisor). Treatment options
include extraction of the canine tooth, or orthodontic correction using
brackets and chains.
What is an example of a class 1 malocclusion and how can it be treated?
Linguoversion of the mandibular canines (‘base narrow
canines’). This may be due to mandibular width that is too narrow
(‘base narrow’) but is more often due to linguoversion of the
canine teeth- they are too upright. This allows contact of the
palatal mucosa by the mandibular canines when the mouth is
closed which leads to pain, mucosal ulceration and eventually
oronasal fistula formation.
What is the treatment for class 1 malocclusion Linguoversion of the mandibular canines (‘base narrow
canines’)?
An easy treatment option if the jaw lengths are normal, and there is space in
which to tip the mandibular canine laterally is ball therapy, described by
Verhaert in 1999. The dog must hold a firm rubber ball just wider than the
canine teeth for 15 minutes three times daily. The force of holding the ball acts
as an orthodontic force and can tilt the canine teeth into the correct position.
What is another treatment for class 1 malocclusion Linguoversion of the mandibular canines?
A further option is referral for placement of an orthodontic device known as an
incline bite plane. This is an acrylic device fitted to the maxillary canine teeth
with an in-built ramp of about 60. When the mandibular canines touch the ramp
as the mouth closes, they are deflected into a normal position.The incline plane
is removed after 4-6 weeks, but should be regularly checked to ensure the
mouth is free from inflammation,and the construct has not broken.
What is another treatment for class 1 malocclusion mild Linguoversion of the mandibular canines?
In some mild cases, all that is required is gingivoplasty to re-contour the gingiva
and allow space for the canine tooth.
What is another treatment for class 1 malocclusion Linguoversion of the mandibular canines?
Crown shortening and vital pulp therapy is also a possibility. This reduces
the height of the mandibular canine tooth so it does not contact the palatal
mucosa on mouth closure. This inevitably exposes the pulp, so that pulp
treatment is required in order to maintain its vitality. Lifelong monitoring is
required to ensure the pulp remains vital and healthy. Success rates are
however high, with a reported 92% success (Luotonen et al 2014).
What is a class 2 malocclusion?
Class 2 malocclusion (mandibular distoclusion)
An inclined bite plane fitted to the
maxillary canine teeth. Note the 60°
angulation which forms the ramp for
the mandibular canine teeth.
Gingovoplasty for
treatment of mild
mandibular canine
linguoversion
Crown shortening and vital pulp
therapy in a 12m MN SBT with
class 1 malocclusion and
linguoversion of the left mandibular
canine tooth (304)
The mandibular arch occludes distal to its
normal position relative to the maxilla. This
often results in linguversion of the mandibular
canines as they become trapped medial to the
maxillary canines. This results in palatal
contact, mucosal ulceration and eventual ONF
formation.
What are the treatment options for this Class 2 malocclusion (mandibular distoclusion)?
Treatment options are orthodontic movement (difficult as the tooth has to come
rostral and lateral), crown shortening and vital pulp therapy or extraction.
What is a class 3 malocclusion (mandibular mesioclusion)?
The mandibular arch occludes rostral to its normal
position relative to the maxilla. In this situation, the
best treatment is to extract any maxillary incisors
causing mucosal trauma. Affected animals may
have difficulty prehending food, so owners should
experiment with plates/bowls and different
consistency foods.
What is a Class 4 malocclusion?
This describes maxillomandibular asymmetry in a
rostrocaudal, side-to-side or dorsoventral direction.
Treatment is again aimed at alleviating abnormal
tooth-tooth or tooth-soft tissue contact.
What is a rostral crossbite?
One or more of the mandibular incisor teeth is labial to the opposing maxillary
incisor teeth when the mouth is closed. Similar to anterior crossbite in human terminology.
What is a caudal crossbite?
One or more of the mandibular cheek teeth is buccal to the opposing maxillary
cheek teeth when the mouth is closed. Similar to posterior crossbite in human
terminology.
How to feline malocclusions commonly occur?
Feline malocclusions can occur as a developmental condition, but are more
often related to a post-traumatic consequence. Treatment of
jaw fractures should prioritise restoration of normal occlusion.
Any residual malocclusion reducing jaw function and limiting
mouth movement should consider tooth extraction to alleviate.
How do caudal malocclusions in the cat present?
They present as a
proliferative or ulcerative lesion of the buccal
mucosa in the area of the mandibular molar,
often due to cuspal contact from the maxillary
4th pre-molar.
How are caudal malocclusions in cats treated?
Treatment involves excising the mass, and treating the associated
tooth causing the trauma. This can be non-invasively, by performing
odontoplasty followed by application of a bonded sealant, or extraction of the
tooth in question.
Discuss Deciduous malocclusions?
These can also occur and should be identified and treated. Linguoversion of the
mandibular canines +/- class II malocclusion is relatively common.
What is the treatment for Linguoversion of the deciduous
mandibular canines +/- class II malocclusion?
This causes
pain! In addition it is postulated that the impingement of
the mandibular canine in the resultant hole in the palatal
mucosa can impinge on mandibular growth. Extracting
these mandibular canines will therefore alleviate pain, and
also allow the mandibles to grow to their genetic potential
(which may still be a class II malocclusion). Beware that
extraction of deciduous teeth is challenging as the teeth are long and slender,
and break very easily. Consider the position of the developing permanent tooth
buds to avoid iatrogenic damage to them- they are positioned lingual to deciduous mandibular canine teeth. A decision should be made concerning the
level of pain and restriction of jaw growth before attempting extraction, and then
is best performed around 12 weeks of age.
What can sharpei’s get?
What are differentials for feline caudal malocclusions/
‘pyogenic granuloma’?
