Periodontology Flashcards
What is the correlation between dog size and periodontitis?
In dogs, the incidence of periodontal disease is inversely proportional to the size of the
patient. Small and toy breeds appear to be far more susceptible, and the incidence
decreases with the size of the patient. Greyhounds and other sight hounds are exceptions
to this rule and are one of the few large breeds that appears to be very susceptible to
periodontal disease.
It could be associated with the fact that smaller breeds have relatively large teeth in
relatively small mouths. They therefore have relatively large crowns and relatively large
areas onto which plaque could accumulate. It has been shown that the gingiva in small
breed dogs are thinner and potentially more susceptible to damage by inflammation. In
general, small and toy breeds are less likely to accept toothbrushing and other attempts at
dental home care.
The periodontium represents the tissue involved in attachment of the tooth to the bone of
the jaw. It consists of:
- The gingiva
- The periodontal ligament
- The alveolar bone
- Cementum
The oral mucosa can be divided into three main groups:
- The Alveolar mucosa or lining mucosa comprise of the non-keratinised lining of the
cheeks and lips, the underside of the tongue and the floor of the mouth. - The masticatory mucosa forms the keratinised and parakeratinised mucosa of the
gingiva and hard palate. - Specialised oral mucosa covers the dorsum of the tongue. It has additional sensory
function and will be discussed elsewhere in more detail
What is the alveolar mucosa?
This non-keratinised tissue forms the largest part of the oral mucosa. It is very loosely
attached to the alveolar bone by means of the the loose submucosa, rich in elastic fibres.
What is the Mucogingival Junction (MGJ)?
This line forms the junction between the gingiva and the adjacent alveolar mucosa. It is
usually very clearly demarcated in dogs but less so in cats.
What is gingiva?
This tough, keratinised or para-keratinised tissue forms a band of tough tissue adjacent to
the teeth and extends into the interdental spaces. It covers the coronal aspects of the
alveolar bone including the alveolar margin and extends to the mucogingival junction.
The epithelium of the gingiva of cats and dogs is considered a para-keratinised epithelium
divided into the?
Stratum basale, stratum spinosum, and the stratum corneum.
A completely
keratinised epithelium (containing a stratum granulosum) can occasionally be seen in cats but not normally seen in the gingiva of dogs.
Other cells can occur within the epithelium layer of the gingiva what are they?
- Melanocytes and melanophages. These cells produce melanin granules that is
responsible for the pigmentation often noticed in the gingiva. Melanin granules
produced by melanocytes are phagocytosed and stored by melanophages. - Merkel cells are encountered in the deeper layers of the epithelium and probably have
a sensory function. - Langerhans cells occur in the deeper layers of the epithelium. These cells originate
from bone marrow and their function is the presentation of antigens to lymphocytes.
Connective tissue Layer of the Gingiva
This connective tissue layer or also call the submucosa, is divided into the superficial
papillary layer that interdigitates with the rate pegs of the epithelium. This strong
connection between these layers explains the strength of this tissue. The reticular layer of
these mucosa lies adjacent to the alveolar bone
Blood vessels nervous and lymphatics are positioned within the submucosa. Apart from
collagen fibres and fibroblasts, lymphocytes, plasma cells, neutrophils eosinophils and
macrophages contribute to this tissue.
The gingiva can macroscopically be divided into the attached and free gingiva
What is attached gingiva?
This forms the largest part of the gingiva and is very firmly attached to the underlying
alveolar bone. Collagen fibres of the gingival submucosal are firmly attached and
interwoven with collagen fibres of the periosteum and is also referred to as a
mucoperiosteum. At the alveolar margin, some of these fibre bundles merge with collagen
fibres that extend over the alveolar margin from the periodontal ligament. Bundles of
collagen fibres known as Sharpie’s fibres, embedded in the cementum, disperses into the
submucosa of the attached gingiva, just coronal to the alveolar margin.
What is Gingival Stippling?
These fine, irregular bumps or depressions can occasionally be detected on the surface of
the attached gingiva. The distribution vary significantly between individuals and the area of
the gingiva. It is usually more pronounced at canine and carnassial teeth and could be
absent in premolars. Gingival stippling appears to be more common in older animals and
might be associated with the degree of keratinisation of the tissue.
Discuss Gingival Height?
The depth or height of the gingiva varies between different areas of the mouth and the teeth
that occurs there. The gingiva is less well demarcated in cats but in general it is widest in
the areas of the canine and carnassial teeth. Dogs have attached gingival heights of 2-5
mm and cats 1-2 mm. The height of the gingiva is affected by conditions like gingivitis.
Once the height of the gingiva reduces to below 2 mm, ulceration of the mucosa is likely
and a general deterioration in periodontal health usually follows.
Discuss Gingival thickness?
The thickness of the gingiva varies between individuals and in general the gingiva in
smaller dog breeds is thinner than in larger dog breeds. Gingival thickness is greatest at
the canine and carnassial teeth.
Where is the attached gingiva?
The attached gingival extends from the mucogingival junction to a few millimetres away
from the gingival margin, the borders of the free gingiva.
What is the free gingiva?
The free gingiva is the part of the gingiva that is not attached to alveolar bone or to the
cementum of the tooth. This fine edge of about 2 mm in dogs extends from the gingival
margin to a level that corresponds to the deepest aspects of the gingival sulcus. This
margin is as wide as the depth of the gingival sulcus. The layer of epithelium inside the
gingival sulcus loses its rete pegs and is no longer parakeratinised. It forms the sulcular
epithelium that terminates as the junctional epithelium that is attached to surface of the
crown by means of hemidesmosomes.
Discuss Junctional epithelium?
In the depths of the sulcus this epithelium are attached to the tooth surface by means of
hemidesmosomes, and this distinct part of the sulcular epithelium is referred to as the
junctional epithelium. The latter could be only two cell layers thick, reduced from about 20
layers of cells at the gingival margin.
The basal cell layer of the sulcular epithelium divides actively and creates a migration of
cells towards the gingival margin but also towards the gingival sulcular space. Once
desquamated these cells contribute to the gingival crevicular fluid. The turnover of the cells
of the junction epithelium is very short (4 - 6 days) this is twice as fast as cells elsewhere
in the oral epithelium with a turnover time of 6 -12 days.
What is the Sulcular Epithelium?
This non-keratinised epithelium forms the gingival aspect of the gingival sulcus. Rete pegs
disappears at the gingival margin.
