INTRODUCTION TO ORAL AND DENTAL DISEASES. DR.Rami ALJUAIDI. ORAL MUCOSA. The oral mucoua is the mucous membrane that covers all oral structures except the clinical crowns of the teeth. It is composed of two layers: (1) the stratified squamous
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INTRODUCTION TO ORAL AND DENTAL DISEASES DR.Rami ALJUAIDI
ORAL MUCOSA The oral mucoua is the mucous membrane that covers all oral structures except the clinical crowns of the teeth. It is composed of two layers: (1) the stratified squamous epithelium and (2) supporting connective tissue, called the lamina propria. The epithelium may be keratinized, parakeratinized, or nonkeratinized depending upon its location.
The lamina propria varies in thickness The oral mucosa may be divided into three major functional types: (1) masticatory mucosa, (2) lining or reflective mucosa, and (3) specialized mucosa.
The masticatory mucosa is composed of the free and attached gingiva and the mucosa of the hard palate. The epithelium of these tissues is keratinized, and the lamina propria is a dense, thick, firm connective tissue containing collagenous fibers. The dense lamina propria of the attached gingiva is connected to the cementum and the periosteum of the bony alveolar process
The lining or reflective mucosa covers the inside of the lips, cheek, vestibule, lateral surfaces of the alveolar process (except the mucosa of the hard palate), floor of the mouth, soft palate, and inferior surface of the tongue. Lining mucosa is a thin, movable tissue with a relatively thick, nonkeratinized epithelium and a thin lamina propria. The submucosa is composed mostly of thin, loose connective tissue with muscle and collagenous and elastic fibers, with different areas varying from one another in their structure. The junction of lining mucosa with masticatory mucosa is the mucogingival junction, located at the apical border of the attached gingiva facially and lingually in the mandibular arch and facially in the maxillary arch . .
the specialized mucosa covers the dorsum of the tongue and the taste buds. The epithelium is nonkeratinized except for the covering of the dermal filiform papillae
The cells of the outermost layers of the stratified squamous epithelium are not all squamous (flat). some of the cells seem to be separating from the surface of the tissue. This is called sloughing and is a normal process in epithelial tissues that form coverings and linings, especially the stratified tissues.
Keratine covers the dry areas of the skin whilest the moist areas of the skin are not keratinized
The epidermis is the outermost layer of the skin, composed of terminally differentiated stratified squamous epithelium, acting as the body's major barrier against an inhospitable environment. It is the thinnest on the eyelids at .05mm and the thickest on the palms and soles at 1.5mm
Cellular components The epidermis is [avascular], nourished by [diffusion] from the [dermis], and composed of four types of cells,i.e: keratinocytes, melanocytes, Langerhans cells, and the Merkel cells.Keratinocytes are the major constituent, constituting 95% of the epidermis. . The melanocyte produces pigment (melanin), the Langerhans' cell is the frontline defense of the immune system in the skin, and the Merkel's cell's function is not clearly known.
Layers The epidermis is composed of 4-5 layers depending on the region of skin being considered. Those layers in descending order are the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The term Malpighian layer refers to both the basal and spinosum layers
Cellular kinetics The stratified squamous epithelium is maintained by cell division within the basal layer. Differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where anucleate corneal cells are continually shed from the surface (desquamation). In normal skin the rate of production equals the rate of loss, taking about two weeks for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum
keratinisation - organic process by which keratin is deposited in cells
parakeratosis • the persistence of nuclei in the stratum corneum keratin layer of stratified squamous epithelium.
Precancerous Lesions • What is a precancerous lesion?A precancerous lesion is a change in some areas of your skin that carries the risk of turning into skin cancer. It is a preliminary stage of cancer. These precancerous lesions can have several causes; UV radiation, genetics, exposure to such cancer-causing substances (carcinogens) as arsenic, tar or x-ray radiation. • Because precancerous lesions can turn into skin cancer and since skin cancer can possibly lead to death it is very important to catch skin cancer at an early stage. If you discover any suspicious lesion take it seriously and seek the advice of a dermatologist.
Oral and MaxillofacialPathology • . GENERAL • Oral mucosa has the same susceptibility to pathological change as does other covering tissue. Common abnormalities of the skin and the gastrointestinal tract may evidence themselves on oral mucosa. Local, focal oral mucosal lesions, generalized mucosal involvement, or intraoral lesions associated with a systemic problem may be caused by bacterial, fungal, or viral organisms. Benign or malignant lesions must always be considered when examining a patient's mouth.
Elementary lesions of the oral mucosa Diseases that manifest themselves on the oral mucosa generally produce tissue morphological alterations as clinical signs that are so characteristic, that they have been classified as primitive elementary lesions. Many of these lesions do not retain their original appearance due to causes such as: traumatism, mastication, maceration, movement of the tissues, and time itself; the lesions thus derived from these primitive or primary ones are known as secondary lesions. This labelling is important in terms of order of appearance but not clinical importance, since in many cases these lesions are as useful as the primary ones to help establish a diagnosis.The primitive lesions that occur most frequently, both on skin and mucosa are: spots, papules, nodules, vesicles, blisters, pustules, keratosis, warts, tubercules, hives and tumors.The most common secondary lesions of the oral cavity are: erosions, fissueas or cracks, ulcers, ulcerations, scabs, scars y desquamations."Elementary lesions are like the letters of the alphabet. Without a knowledge of them you cannot learn the language of stomatology". David Grinspan
VESICLE A vesicle is a circumscribed, superficial elevation on the skin or mucous membrane containing fluid (serum, plasma, or blood). If the vesicle opens, it becomes an ulcer (an inflammatory loesin
ULCER (Figure 1- 7) An ulcer is an open sore of a superficial nature extending below the covering epithelial surface. The base of an ulcer is composed of granulation tissue resulting from initial healing. A secondary infection may develop in an ulcer, resulting in delay of the healing and repair process. A common cause of oral ulceration is trauma, which might even be a result of toothbrush injury. Irritation from a rough or broken tooth surface can also result in ulceration. Some ulcers start with vesicle formation. This painful ulceration on the lateral border of the tongue represents a nonspecific response to tissue injury. The cause of an ulcer must be determined and appropriate treatment initiated. Normal healing will often result without use of medication
Spots A spot is just a change of coloration of the oral mucosa, which is not elevated. They occur very frequently. They are primarily constituted by variations of hematologic or melanocitic pigments, but also by the organism’s own pigments or external ones. Structural changes of the soft tissues also produce changes in coloration.
White spots due to: LichenLeukoplakia on the oral mucosa
Brown spots due to: Pigmentation in AIDS Racial pigmentation Fixed pigmented erythema
Red spots due to: PúrpuraFlat hemangioma on skinand oral mucosa
Spots due to foreign pigments: Due to ballpoint pen
Vesicles, bullae (blisters) and pustules Vesicles, bullae and pustules are superficial lesions with a liquid content. The two first ones can only secondarily become pustulent by overlaying infections. The pustule initially contains pus and is very rare in th oral mucosa. These lesions are rarely found intact when occuring inside the mouth, since masticatory trauma ruptures them rather easily.Vesicles are primarily formed by spongiosis of an eczema or by a ballooning and reticular degeneration during viral infections.The mechanism by which a blister is formed is fundamental to confirm the diagnosis of the underlying disease. Blisters may be intraepithelial, by acantholysis of the spiny cells, as occurs in the different types of pemphigus, or subepidermal separating the connective tissue from the epithelium as occurs in the pemphigoidal lesions: Duhring’s disease, erythema multiforme, and bullous pemphigoid.
Vesicles due to: Labial herpes Coalescence of vesicles during labial herpes Herpes zoster
Vesiculopustular lesions due to: Varicella
Bullae (blisters) due to: • Pemphigus on skin • Pemphigus blistered “roof” • Pemphigus on the gingiva
Pustules due to: Impétigo
Pigmented oral lesionsMost red oral lesions are inflammatory in nature, but some are potentially malignant, especially erythroplasia.
Causes of red lesions Widespread redness Localised red patches Candidiasis Candidiasis Iron deficiencyErythroplasia Avitaminosis B Purpura Irradiation mucositisTelangiectases Lichen planus Angiomas Mucosal atrophy Kaposi's sarcoma Polycythaemia Burns Lichen planus Lupus erythematosus Avitaminosis
Erythroplasia (erythroplakia)Erythroplasia is a rare, isolated, red, velvety lesion that affects patients mainly in their 60s and 70s. It usually involves the floor of the mouth, the ventrum of the tongue, or the soft palate. This is one of the most important oral lesions because 75-90% of lesions prove to be carcinoma or carcinoma in situ or are severely dysplastic. The incidence of malignant change is 17times higher in erythroplasia than in leucoplakia. Erythroplasia should be excised and sent for histological examination Erythroplasia is an isolated red lesion that typically occurs in elderly peopleIt is usually dysplastic or malignant and is bestremoved
Erythematous candidiasis • Erythematous candidiasis may complicate treatment with corticosteroids or antimicrobials and cause widespread erythema and soreness of the oral mucosa, sometimes with thrush. It may also occasionally be seen in HIV infection, xerostomia, diabetes, and in people who smoke. • Red persistent lesions are especially noticeable on the palate and tongue. Median rhomboid glossitis (central papillary atrophy) is a red depapillated rhomboidal area in the centre of the tongue dorsum, now believed to be associated with candidiasis. Biopsy may show pseudoepitheliomatous hyperplasia, but the condition is not potentially malignant. • ManagementErythematous candidiasis may respond to stopping smoking and antifungal agents (usually fluconazole).
Denture induced stomatitis (denture sore mouth)This is a common form of mild chronic erythematous candidiasis, usually seen after middle age as erythema limited to the area beneath an upper denture. The fitting surface of the denture is infested mainly with Candida albicans. Despite its name, this condition is rarely sore, though angular stomatitis may be associated. Patients are usually otherwise healthy.
Factors that predispose to denture induced stomatitis include wearing dentures (especially through the night), poor oral and denture hygiene, xerostomia, and carbohydrate-rich diets. It is not caused by allergy to the denture material. Management includes Denture stomatitis occurs mainly when Candida proliferate beneath and infest the dentureIt may be asymptomatic but may be associated with angular stomatitisDenture wearing should be minimised and the infection eradicated
Eradicating infection by soaking dentures overnight in chlorhexidine or 1% (v/v) hypochlorite solution then using miconazole denture lacquer. Metal dentures should not be soaked in hypochlorite as they may discolour Using miconazole gel (5ml), nystatin pastilles (100000 units), or amphotericin lozenges (10mg) in the mouth four times daily for up to one month Using systemic fluconazole 50mg daily for resistant cases Adjustment of the dentures. Other red lesionsPetechiae are usually caused by trauma or suction but may also be seen in thrombocytopenia, amyloidosis, localised oral purpura, or scurvy. Telangiectasia may be a feature of hereditary haemorrhagic telangiectasia or systemic sclerosis.
Non keratotic white lesions • Habitual cheek biting • Burns • Uremic stomatitis • Radiation mucositis • Koplik.s spots
Cheek Chewing • White lesions of the oral tissues may result from chronic irritation • due to repeated sucking, nibbling, or chewing. • These insults result in the traumatized area becoming thickened, • scarred, and paler than the surrounding tissues. Cheek • chewing is most commonly seen in people who are under • stress or in psychological situations in which cheek and lip • biting become habitual.Most patients with this condition are • somewhat aware of their habit but do not associate it with • their lesions.
The white lesions of cheek chewing may sometimes be confused with other dermatologic disorders involving the oral mucosa, which can lead to misdiagnosis. Prevalence rates ranging from 0.12 to 0.5% have been reported
TYPICAL FEATURES • The lesions are most frequently found bilaterally on the posterior • buccal mucosa along the plane of occlusion. They may • be seen in combination with traumatic lesions on the lips or • tongue. Patients often complain of roughness or small tags of • tissue that they actually tear free from the surface. This produces • a distinctive clinical presentation • The lesions are poorly outlined whitish patches that may be • intermixed with areas of erythema or ulceration. The occurrence • is twice as prevalent in females and three times more • common after the age of 35 years. • The histopathologic picture is distinctive and includes • hyperparakeratosis and acanthosis. The keratin surface is usually • shaggy and ragged with numerous projections of keratin • that demonstrate adherent bacterial colonies.When the lesion • is seen on the lateral tongue, the clinical and histomorphologic • features mimic those of oral hairy leukoplakia.
TREATMENT AND PROGNOSIS Since the lesions result from an unconscious and/or nervous habit, no treatment is indicated. However, for those desiring treatment and unable to stop the chewing habit, a plastic occlusal night guard may be fabricated. Isolated tongue involvement requires further investigation to rule out oral hairy leukoplakia especially when appropriate risk factors for infection with human immunodeficiency virus (HIV) are present. Differential diagnosis also includes chemical burns, and candidiasis.
Morsicatio buccarum represented by a frayed macerated irregular leukoplakic area in the cheek.
burns • Chemical Injuries of the Oral Mucosa • Transient nonkeratotic white lesions of the oral mucosa are • often a result of chemical injuries caused by a variety of agents • that are caustic when retained in the mouth for long periods • of time, such as aspirin, silver nitrate, formocresol, sodium • hypochlorite, paraformaldehyde, dental cavity varnishes, acidetching • materials, and hydrogen peroxide. The white • lesions are attributable to the formation of a superficial • pseudomembrane composed of a necrotic surface tissue and • an inflammatory exudate.
burns Aspirin burn, creating a pseudomembranous necrotic white area.