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