VI. Use Participle I or II instead of subordinate clauses.

1. The direct cause of periodontal disease is the adherent colonized microbial mass which is found on the tooth surface at the gingival crest in the sulcus and in the periodontal pocket.

2. The organisms nearest the tooth surface may become infiltrated with mineral deposits that form calculus.

3. This is achieved at present by the dentist who educates and supervises the child through adolescence and adulthood by early discovery and removal of all plaques.

VII. Read and translate the sentences paying attention to the subordinate clauses.

1. When present in the water supply fluoride automatically forms part of the diet during the period of tooth formation.

2. If used regularly fluoride toothpaste gives a slightly greater caries reduction than ordinary toothpaste.

3. If left unchecked gingivitis can progress to a more severe condition called periodontitis.

4. Second teeth may become loose and, if untreated, can be lost.

5. The patient is given a mirror to see the shade, shape and arrangement of the teeth, and if dissatisfied with them, any necessary adjustments can then be made in the surgery.

6. These chemotherapeutic agents when used properly will control the development of disease.

VIII. Read and translate the text.

Periodontal Disease

Archaeological studies and the historic literature have shown periodontal disease has affected mankind since early in evolution. Recent epidemiological studies have shown that the disease is the major cause of tooth loss after 35 years of age.

The direct cause of periodontal disease is the adherent colonized microbial mass found on the tooth surface, at the gingival crest, in the sulcus and in the periodontal pocket. The pathogenesis of periodontal disease begins at the time the tooth erupts. The tooth is the stony foundation to which the microbes adhere and on which they colonize. As the microorganisms develop on the tooth surface the first microscopic changes occur on the gingival next to them. These are proliferation and desquamation of epithelium, serous and cellular exudation and lysis of connective tissue fibers. The organisms nearest to the tooth surface may become infiltrated with mineral deposits forming calculus.

Lysis of the circular fibers occurs. With loss of the supporting connective tissues the gingiva loses its firmness, stands away from the tooth surface; the sulcus deepens and the periodontal pocket develops.

The most important therapeutic aim is the removal of plaque and calculus by the therapeutist. There is no doubt the gingival inflammation subsides and can be maintained at a very low level by these procedures.

The ideal future task may be the generation of bone and connective tissues attachments which have been destroyed by the disease process. Significant regeneration of bone and connective tissue may be achieved by grafting a number of substances but these procedures are experimental at present.

The most important aim is prevention of the occurrence of periodontal diseases. This is achieved at present by the dentist educating and supervising the child through adolescence and adulthood by early discovery and removal of all plaques.

Our best hopes for the future lies with the discovery and development of effective chemotherapeutic antiplaque agents. It seems realistic to expect that within the lifetime of many of us there will be agents which, when used regularly, will effectively prevent plaque formation or at least control its pathogenic components. The periodontal disease can be halted and healthy dentition achieved.