CLASSIFICATION OF CARIOUS LESIONS AND TOOTH PREPARATION.

Transcription

1 CLASSIFICATION OF CARIOUS LESIONS AND TOOTH PREPARATION. ١

2 G.V. BLACK who is known as the father of operative dentistry,he classified carious lesions into groups according to their locations in permanent teeth. the same classification is used to refer to cavity preparation. ٢

3 The Man behind the Name: History: Greene Vardiman Black ( ), commonly known as G.V. Black, is known as one of the founders of modern dentistry in the USA. He was born near Winchester, Illinois on, and began studying medicine with the help of his brother, Dr. Thomas G. Black. In 1857, he met Dr. J.C. Speer, who taught him the practice of dentistry.

4 Research and Study He researched many important topics to dentistry, including the best composition for dental amalgams and the cause of dental fluorosis. One of his many inventions was a foot-driven dental drill. Black was the first to use nitrous-oxide for "extracting teeth without pain." He is also known for his principles of tooth preparations,the phrase, "extension for prevention," is still famous in the dental community today and represents Black's idea that dentists should follow preventive measures to aid patients from developing tooth decay.

5 He organized a classification system with five categories for different patterns of tooth decay which is still in use today. Since that time, only one more category has been added to his classification system. The Invention

6 Introduction Steps of cavity preparation involve the removal of carious tooth structure and restoration of the tooth to its original anatomic form with a suitable restorative material. The design of the cavity preparation is determined first by the location of the caries lesion in the tooth.

7 Use Of Principles Outline form: The shape or outline of the cavity preparation. Convenience form: the need to obtain access for the instruments as the operator is preparing the cavity or placing the restoration. Retention form: The need to provide retention for the restorative material. Resistance form: resistance to stress on the restoration and the tooth to the forces of biting and chewing.

8 ESTABLISH OUTLINE FORM: Outline form is based on the location and extent of the carious lesion, tooth fracture, or erosion. Outline Form

9 OBTAIN CONVENIENCE FORM: Convenience form allows adequate observation, accessibility, and ease of operation during preparation and restoration of the tooth. Convenience Form

10 OBTAIN RETENTION FORM: Retention may be obtained through mechanical shaping of the preparation to retain the restoration and / or via bonding procedures that attach the restorative material to tooth structure. Retention Form

11 OBTAIN RESISTANCE FORM: Resistance for the remaining tooth structure and for the restoration must be designed in the preparation, so the tooth and the restoration are resistance to fracture during function. Resistance Form

12 Introduction G.V. Black organized a classification system with five categories for different patterns of tooth decay which is still in use today. Since that time, only one more category has been added to his classification system.

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14 Class (I) lesions occur in pits and fissures on the facial, lingual, and occlusal surfaces of molar and premolar. ١٤

15 Class 1 Class (I) lesions occur in pits and fissures on the facial, lingual, and occlusal surfaces of molar and premolar, and the lingual pits of incisors.

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18 Class (II) lesions occur on the proximal surfaces of the posterior teeth (molars and premolars ). ١٨

19 Class 2 Class (II) lesions occur on the proximal surfaces of the posterior teeth (molars and premolars).

20 Class (III) lesions occur on the proximal surfaces of anterior teeth (1, 2, 3,teeth) Class 3 cavities do not involve an incisal angle ٢٠

21 Class 3 Class (III) lesions occur on the proximal surfaces of anterior teeth (1, 2, 3, teeth) Class 3 cavities do not involve an incisal angle.

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23 Class 4(IV) lesions occur on the proximal surfaces of anterior teeth when the incisal angle requires restoration. ٢٣

24 Class 4 Class 4(IV) lesions occur on the proximal surfaces of anterior teeth when the incisal angle requires restoration. The angle may have to be removed because of its fragility or for proper placement of the restoration.

25 the angle may have to be removed because of its fragility or for proper placement of the restoration. ٢٥

26 ٢٦

27 Class 5(V) lesions occur on smooth facial and lingual surfaces in gingival third of teeth. ٢٧

28 Class 5 Class 5(V) lesions occur on smooth facial and lingual surfaces in gingival third of teeth. Class 5 cavities begin close to gingiva and may involve a cementum or dentinal surface as well as enamel.

29 Class 5 cavities begin close to gingiva and may involve a cementum or dentinal surface as well as enamel. ٢٩

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31 Class 6(VI) lesions are pit or wear defects on the incisal edges of anterior teeth or the cusp tips of posterior teeth. ٣١

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33 Class 6 Class 6(VI) lesions are pit or wear defects on the incisal edges of anterior teeth or the cusp tips of posterior teeth. This Class was not developed by G.V. Black

34 The names of surfaces are often abbreviated (distal D, lingual L, mesial M,occlusal O, buccal B...etc MO,DO,BO,.etc ٣٤