Dentition Flashcards
Describe the structure of a generalised tooth
- outer enamel
- Dentine
- Pulp chamber
- Gingival cervice
- Gingiva
- Peridontal ligament
- Root canal
- Cementum
- Apical foramen
- Genioglossus msucle
Enamel
Hard outer part projecting above gums
Ectodermal origin
Formed by ameloblasts
It is acellular and cannot regenerate so if chipped, remains
Dentine
- Mesodermal in origin.
- Formed by ODONTOBLASTS
- Forms the bulk of the tooth
- 2nd hardest tooth material, enamel is harder
- Structure is similar to bone
- Secondary dentine is darker in appearance than primary dentine.
- Tertiary dentine may occur at sites of injury.
What is the difference in dentine to bone
- in bone the OSTEOBLASTS stay within the bone matrix, in teeth the ODONTOBLASTS (the dentine producing cells), recede from the newly formed dentine and remain as a continuous layer on the surface of the pulp cavity. This produces SECONDARY DENTINE throughout life, which gradually reduces the size of the dental pulp cavity. – more an more dentine produced throughout life = reduces bulk cavity
Cementum
Mesodermal in origin
Formed from calcified connective tissue
Forms the outer lining of the tooth in the socket in brachydont teeth
It is the least hard of the calcified tissues of the tooth
It is continuously, but slowly, produced throughout life, so is thicker in older animals.
Pulp cavity
It reflects the external shape of the tooth i.e. is present in each tooth root.
It is open at the apical foramen. (lower teeth = bottom, upper = top)
Central part of tooth containing nerve fibres, lymphatic and blood vessels
Smaller in older animals as secondary dentine fills in pulp cavity.
Periodontium
What it consists of
Role
This term described the functioning unit of several anatomical components
- It consists of the Gingiva, periodontal ligament, cementum and alveolar bone.
- Functional unit
- Role = anchor tooth into skull and provide a suspensory apparatus to absorb stresses induced at biting
Gingiva
- oral mucosa that covers the alveolar processes of the jaws and covers the neck of the teeth. It is composed of keratinized stratified squamous epithelium
- At coronal bit = proud = free ginigiva
7Periodontal Ligament
- Is made of collagen fibres
- Attaches to the cement of the tooth and the Alveolus
- These fibres are arranged in a sling formation – allowing small movements of the teeth during mastication, and acting as shock absorbers.
What is the innervation of the teeth?
- All teeth are innervated by branches of the TRIGEMINAL NERVE - cranial nerve V
What are the upper and lower teeth innervated by?
- Upper = supplied by the MAXILLARY (or superior) ALVEOLAR NERVE (from the maxillary division of the Trigeminal Nerve).
- Lower = supplied by the MANDIBULAR (or inferior) ALVEOLAR NERVE (from the mandibular division of the Trigeminal nerve).
What type of teeth do we describe out domestic species as having and what to these terms mean?
- Diphyodont Heterodont
- D = deciduous and permanent teeth = adult and baby
- H = diff type of specialised teeth
list 6 dental terms
- Hypsodont
- Brachydont teeth
- Aradicular/ Elodont
- Radocular/ Anelodont
- Clinical crown
- Anatomical crown
Hypsodont
those of horses, high or long crowned with unerupted crown lying beneath the gum in all but very aged animals. The root of the tooth is generally shorter than the crown.
Brachydont teeth
those of the dog and cat (and human), are low crowned - where all of the crown has erupted by adulthood. The root of the tooth is generally longer than the crown.
Aradicular/ Elodont
teeth grow throughout life and never develop true roots. Always hyposodont.
Radocular/ Anelodont
teeth with a true anatomical root structures and do not continuously grow throughout life. Can be hypsodont or brachydont
Clinical crown
this is the exposed part of the tooth, regardless of structure.
Anatomical crown
this is the enamel covered part of the tooth regardless of location.
Name and describe orientations
- Surface next to the lips – LABIAL
- Surface next to the cheek -BUCCAL
- Surface next to the tongue - LINGUAL
- Surface touching the tooth in front – MESIAL
- Surface touching the tooth behind - DISTAL
- Masticatory surface (‘table’) - OCCLUSAL
The healthy mouth
What maintains pH?
- Normal occlusion
- Normal oral pH in dogs and cats is 7.5
- Saliva maintains this and also contains enzymes, lysozymes and immunoglobulins that moderate bacterial colonisation. Also mechanically washes teeth. Also has some anti-fungal and antiviral actions.
What are commonly occurring dental problems in small carnivores?
- CONGENITAL MALOCCLIUSIONS
- Malocclusion – different head shapes – esp brachycephalic, but also sometimes seen in dolicocephalic breads.
- Prognathism = lower jaw to long (brachycephalic)
- Brachygnathism = lower jaw too short (dolicocephalic
What is the most common oral disease seen in small animals?
- Periodontal disease
- a. First stage is gingivitis - inflammation of the gingiva
b. Second stage - early periodontitis – inflammation of gingiva and periodontal ligament
c. Third stage - further breakdown of support tissues, tooth mobility, tooth loss. Advanced periodontal disease in the upper dental arcade, especially of the canine teeth, can lead to oronasal fistulas
Pig dentition
- Omnivores like us to more generalised dentition
- Lower incisors point forward
- Canines (tusks) remain open rooted in the male and continue to grow
- Upper and lower canines rub = sharp
- Females roots remain open for 2 yrs = grow, after = stop
- Little differentiation between premolars and molars but become larger the more cuadal
- very tumercular (lumpy) occlusal surface for crushing food
What are piglet teeth like?
- born with 8 upper and lower incisors and canines
- v sharp and point forward so often nipped by stock men
- full adult dentition after 18 months
