Odontogenic cysts

The odontogenic cysts are derived from epithelium associated with the development of the dental apparatus. Since several types of these cysts may occur, dependent chiefly upon the stage of odontogenesis during which they originate, various investigators have attempted to give a classification and system of nomenclature of the lesions. One of the simplest and yet most practical is a classification of Robinson and Koch:

l) primordial cyst;

2) dentigerous cyst;

3) periodontal cyst: a) apical, b) lateral; 4) gingival cyst.

A cyst is defined as a pathologic epithelium-lined cavity usually containing fluid or semisolid material. All odontogenic cysts satisfy these criteria, and, in addition, are nearly always completely enclosed within bone. The epithelium associated with each of the odontogenic cysts is derived from one of the following sources: l) a tooth germ; 2) the reduced enamel epithelium of a tooth crown; 3) the epithelial rests of Malascez, remnants of the sheath of Hertwig, or 4) remnants of the dental lamina.

The diagnosis of any of the odontogenic cysts and their correct identification as to type depend upon microscopic examination of the tissue coupled with close study of the clinical and roentgenographic findings.

The apical periodontal cyst is the most common of the odontogenic cysts. It involves the apex of an erupted tooth and is most frequently a result of infection via the pulp chamber and root canal through carious involvement of the tooth.

The gingival cyst is a cyst of gingival soft tissue, occurring in either the free or attached gingiva.

The gingival cyst appears to occur at any age and presents generally as a small, well circumscribed painless swelling of the gingiva, sometimes closely resembling a superficial mucocele. The lesion is of the same color as the adjacent normal mucosa and seldom measures over 1 cm in diameter, generally much less. Histologically, the gingival cyst is a true cyst, since it is an epithelium-lined cavity which usually contains fluid. The lining epithelium is generally very thin, flattened squamous epithelium. The lesion lies free in the connective tissue of the gingiva and may or may not be associated with inflammatory cell infiltration.

Treatment. Local surgical excision of the lesion in adults is usually recommended, and the lesions do not tend to recur. A neoplastic potential has never been reported.

For cysts occurring in infants, generally no treatment is recommended, since these represent the usual progression in the fate of degenerating dental lamina and will ultimately disappear.

BLOOD

КРОВ. ЗАРАЖЕННЯ КРОВІ

PRE-TEXT ASSIGNMENTS

Exercise 1. Practice the pronunciation:

Oxygen [‘oksidZ(ə)n], nutrient [‘nju:triənt], essentially [I’sen∫(ə)li], aqueous [‘eikwiəs],serum [‘siərəm], protein [‘prəuti:n], erythrocyte [ə’riθrəsait], leukocyte [‘lju:kəsait], platelet [‘pleitlit], hemoglobin [,h:mo(u)’gloubin], parasite [‘pærəsait], thrombocyte [‘θrombosait], insufficient [insə’fi∫(ə)nt], through [θru:], hepatitis [hepə’taitis].

Exercise 2. Topic vocabulary:

To oxygenate збагачувати киснем

To dissolve розчиняти

Carbon dioxide вуглекислий газ

To deliver доставляти

Nutrient поживна речовина

Waste products продукти життєдіяльності, відходи

Trace amount сліди (дуже незначна кількість)

To refer (to) відноситись до

Clotting зсідання (крові), коагуляція

Platelet пластинка

Iron залізо

To facilitate сприяти, полегшувати

To resist протистояти

Insufficient недостатній

Bleeding кровотеча

Vector вектор, носій (інфекції)

To transmit передавати

HIV (human immunodeficiency virus) ВІЛ

AIDS (acquired immune deficiency syndrome) СНІД

Exercise 3. Translate into Ukrainian:

Bodily fluid, waste products, whole blood, aqueous solution, iron-containing protein, to facilitate transportation of oxygen, the most numerous cellular elements, the clotting of blood, bleeding disorders, an important vector of infection, acquired immune deficiency syndrome, to be transmitted through contact of blood.

Дата добавления: 2015-11-16