PEDIATRIC DENTISTRY
“Features of the structure and function of
oral mucosa (mucous membrane) in
children. Viral mucous membrane
lesions: clinical features, diagnosis,
treatment and prevention.”
Lecturer: Dr. Katrin Duda
Oral Mucosa
The oral cavity is lined by a mucous membrane that consists of:
mucosa Epithelium Lamina propria A submucosa,
which is not always present
Oral Mucosa
There is considerable variabilty in the type of
epithelium present, as well as in the characteristics of
the connective tissue. As a consequence, several
regions are usually distinguished from one another:
Lining mucosa
Masticatory mucosa (mucoperiosteum)
Specialized mucosa
A transitional zone (vermilion zone)
Lining Mucosa
The epithelium of lining mucosa is a non-keratinized
stratified squamous epithelium, which has a:
A basal layer
An intermediate layer (similar to spinous layer)
A superficial layer
The thickness of the epithelium is variable. For
example, in the buccal mucosa the the epithelium is
relative thick, whereas on the floor of the mouth it is
quite thin.
Lining Mucosa
As in the skin,"immigrant" cells (Langerhans cells,
Merkel cells and melanocytes) are also present
within the basal and suprabasal layers of the
mucosal epithelium. Recall that Langerhans cells
are derived from bone marrow an have an immune
function, Merkel cells are associated with
intraeipthelial nerve endings and and melanocytes
(neural crest origin) synthesize melanin pigment.
Lining Mucosa
The underlying connective tissue (lamina propria) is
separated from the epithelium by a basement
membrane. The lamina propria is similar in structure
and composition to the dermis of the skin. In the
papillary layer there are connective tissue papillae and
epithlial ridges. However, the interface between the
mucosal epithelium and connective tissue is fairly "flat"
compared to that in either skin or masticatory mucosa.
The deeper submucosa is analagous to the hypodermis
or subcutus of the skin, and it contains glands and
adipose tissue.
Lining MucosaAs with other connective tissues, the most common cell type in
both the lamina propria and the submucosa is the fibroblast.
Other cells, particularly macrophages and mast cells, are also
present, and under conditions of inflammation, neutrophils,
lymphocytes and plasma cells may also be seen. Collagen type
I is the predominant fiber component of the extracellular
matrix. Both collagen type III and elastic fibers are found in the
lamina propria and submucosa, but their proportions vary
depending on the region. Clinically, the relatively "loose"
nature of the connective tissue in lining mucosa allows for the
easy and relatively painless injection of local anesthetic
solutions.
Masticatory MucosaIn contrast to lining mucosa, masticatory mucosa has a
keratinized stratified squamous epithelium:
Basal layer
Spinous layer
Granular layer
Cornified layer
Orthokeratinized -- no nuclei present
Parakeratinized -- pyknotic nuclei retained
The epithelial ridges and connective tissue papillae are long
and numerous.
Masticatory Mucosa
In addition to a keratinized epithelium and the complex
epithelial-connective tissue junction, the lamina propria
of masticatory mucosa is often directly attached to the
periosteum of the underlying alveolar or palatal bone,
i.e. there is no submucosa. This arrangement is also
called a "mucoperiosteum". There are exceptions to this
eneralization, however. In the posterior lateral region of
the hard palate, for example, there is a submucosa
containing adipose tissue and numerous minor salivary
glands.
Specific Regional Variation
Differences in both the epithelium and the underlying
connective tissue contribute to regional variation within
the oral cavity. One of the most important functional
aspects of this regional variation is the effects on
permeability. The oral mucosa acts as a permeability
barrier, much like the lining of the intestine. However, in
certain areas (floor of the mouth, ventral surface of the
tongue) both the epithelium and the underlying connective
tissue are thin, and there is an extensive capillary network
in the lamina propria. Transmucosal adsorption of drugs,
for example, occurs rapidly across these surfaces.
The Mucogingival and Mucocutaneous Junctions
The boundaries between lining mucosa and masticatory
mucosa, as well as between the skin and labial mucosa,
are relatively sharply defined.
The mucogingival junction is the border between the
alveolar mucosa and the gingiva.
The mucocutaneous junction is found at the vermilion
zone where the skin is continuous with the labial
mucosa. The line separating the skin from the red
vermilion zone is sometimes called the vermilion border.
Epithelial differentiation: Metaplasia and Dysplasia
The differentiation of epithelium in the oral cavity is
regulated by growth factors and retinoids, as in the skin. In
addition, the underlying connective tissue plays a significant
role in epithelial differentiation. Following wounding,
epithelium at the edges of the wound proliferate to
reepithelkialize the surface. The phenotype of the epithelium
(keratinized versus non-keratinized) is determined largely by
the connective tissue. Thus, gingiva regains keratinized
epithelium, and alveolar mucosa will have its non-keratinized
epithelium restored. This is of considerable clinical
significance when doing gingival and other grafts within the
oral cavity.
Epithelial differentiation: Metaplasia and Dysplasia
Epithelial differentiation can also be influenced by functional
stresses and other factors (e.g. smoking). The linea alba, for
example, is a region of lining mucosa that changes to a
keratinizing phenotype. This is an example of metaplasia. In
metaplasia, the terminal differentiation of the epithelium is
altered, but the basic architecture of is maintained. In
"premalignant lesions", however, you start to see mitotic
activity in the suprabasal layers, and there may be
considerable variability in nuclear morphology. This is
referred to as dysplasia.
Herpes simplex
Oral herpes is an
infection of the lips,
mouth, or gums due to
the herpes simplex
virus.
Herpes simplex
Oral herpes is an infection caused by the
herpes simplex virus. The virus causes painful sores
on the lips, gums, tongue, roof of the mouth and
inside the cheeks. It also can cause symptoms such
as fever and muscle aches.
The herpes simplex virus only affects humans. Mouth
sores most commonly occur in children aged 1-2
years, but they can affect people at any age and any
time of the year.
Herpes simplex
People contract herpes
by touching infected
saliva, mucous
membranes, or skin.
Because the virus is
highly contagious,
most people have been
infected by at least one
herpes subtype before
adulthood.
Herpes simplexThree stages:
Primary infection: The virus enters your skin or mucous
membrane and reproduces. During this stage, oral sores and
other symptoms, such as fever, may develop. The virus may not
cause any sores and symptoms. This is called asymptomatic
infection. Asymptomatic infections occur twice as often as the
disease with symptoms.
Latency: From the infected site, the virus moves to a mass of
nervous tissue in spine called the dorsal root ganglion. There,
the virus reproduces again and becomes inactive.
Recurrence: When experience certain emotional or physical
stresses, the virus may reactivate and cause new sores and
symptoms.
Oral herpes causes
Herpes simplex is a DNA virus that causes sores
in and around mouth. Two herpes subtypes may
cause these sores.
Herpes simplex virus type 1, or herpes-1, which
causes around 80% of cases of oral herpes
infections
Herpes simplex virus type 2, or herpes-2, which
causes the rest.
Oral herpes symptoms
Incubation period: For oral herpes, the amount
of time between contact with the virus and the
appearance of symptoms, called the incubation
period, is 2-12 days. The average is about four
days.
Duration of illness: Signs and symptoms will last
two to three weeks. In addition to below
symptoms, fever, tiredness, muscle aches and
irritability may occur.
Oral herpes symptoms
Pain, burning, tingling or itching occur at the
infection site before the sores appear. Then clusters
of blister erupt. These blisters break down rapidly
and, when seen, appear as tiny, shallow, grey ulcers
on a red base. A few days later, they become crusted
or scabbed and appear drier and more yellow.
Neck lymph nodes often swell up and become painful
The gums may become mildly swollen and red
and may bleed.
Oral herpes symptoms
Oral sores: The most intense pain caused by these
sores is felt when they first appear, and can make
eating and drinking difficult. The sores may occur on
the lips, the gums, the front of the tongue, the inside
of the cheeks, the throat and the roof of the mouth.
They may also extend down the chin and neck.
In people in their teens and 20s, herpes may cause a
painful throat with shallow ulcers and a greyish
coating on the tonsils.
Exams and Tests
Doctor can diagnose oral herpes by looking at
your mouth area. Sometimes, a sample of the
sore is taken and sent to a laboratory for closer
examination. Tests may include:
Viral culture
Viral DNA test
Tzanck test to check for HSV
Treatment
Symptoms may go
away on their own
without treatment in 1
to 2 weeks. Acyclovir Famciclovir Valacyclovir
The following steps can make better:
Apply ice or a warm washcloth to the sores to help
ease pain.
Wash the blister gently with germ-fighting (antiseptic)
soap and water. This helps prevent spreading the virus
to other body areas.
Avoid hot beverages, spicy and salty foods, and citrus.
Gargle with cool water.
Rinse with salt water.
Take a pain reliever such as acetaminophen (Tylenol).
Prognosis
Oral herpes usually goes away by itself in 1 to 2
weeks. However, it may come back.
Herpes infection may be severe and dangerous
if:
It occurs in or near the eye
You have a weakened immune system due to
certain diseases and medications
Prevention
Apply sunblock or lip balm containing zinc oxide to
your lips before you go outside.
A moisturizing balm to prevent the lips from
becoming too dry may also help.
Avoid direct contact with herpes sores.
Wash items such as towels and linens in boiling hot
water after each use.
Do not share utensils, straws, glasses, or other items
if someone has oral herpes.
Varicella
Varicella
(Chickenpox) results
from primary infection.
Intra-oral vesicles of
varicella, when
present, are seen on
the tongue, buccal
mucosa, gingival,
palate and oropharynx.
They generally are not
very painful.
Varicella
Varicella
The varicella-zoster virus may be spread through the
air or by direct contact with the blisters (lesions) of
someone infected with chickenpox or shingles.
Once someone is infected, the virus usually
incubates for 14 to 16 days before a rash appears,
although incubation can last from 10 days to 21
days. There are no symptoms during incubation and
a person is contagious from 1 to 2 days before
symptoms appear. The person remains contagious
until all the blisters have dried and scabs have
formed.
Symptoms and Complications ofVaricella
Flu-like symptoms start to develop a day or two
before an itchy red rash appears. Fatigue, mild
headache, fever, chills, and muscle or joint aches are
typical. The rash emerges as raised red bumps that
turn to teardrop-shaped blisters that are extremely
itchy.
These blisters may appear anywhere on the body,
usually starting on the scalp, spreading to the trunk
or torso, and then to the arms, legs, and face. In
some cases, the rash may even spread across your
entire body, including areas such as the throat,
mouth.
Symptoms and Complications ofVaricella
The blisters come in waves, with new crops
developing as old ones burst. New blisters stop
forming within about 5 days. By the sixth day, most
blisters will have burst, dried, and crusted over. 2
weeks after that, most of the scabs will have
disappeared.
Children usually have a much milder infection and
recover faster than adults. Babies, adults, and those
with weakened immune systems tend to have more
severe and longer-lasting symptoms. They are at
higher risk of developing complications.
Symptoms and Complications ofVaricella
Skin infection from bacteria is by far the most
common complication in children. It may leave
scarring, especially if the child scratches the lesions.
Necrotizing fasciitis ("flesh-eating disease") in
children, though extremely rare, can occur as a
complication of infection entering through the
chickenpox lesions. An awkward problem occurs
when chickenpox blisters appear in the mouth,
throat. Lesions in these places are very
uncomfortable.
Treating and Preventing Varicella
In most cases, treatment is directed at relieving
symptoms until the illness goes away on its own. Non-
medical therapy includes:
keeping the body cool, as heat and sweat aggravate
itchiness
applying cool-water compresses to the affected skin
areas to reduce itchiness
keeping nails cut short and hands clean, as bacteria
found under fingernails can infect open skin lesions
taking daily baths with soap and water, which can
prevent bacterial infection.
Thank you for attention
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