cavity classification and nomenclature (3)

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Introduction to Operative Dentistry
Third Year

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cavity classification and nomenclature (3)

  1. 1. 04/11/34 CAVITY CLASSIFICATION AND NOMENCLATURE Third year UOD Cavity classification & nomenclature: -Describe different tooth numbering systems. -Compile the nomenclature of tooth surface. -Demonstrate the proper terminology and nomenclature of the cavity; cavity wall, floors, line angles, point angles and cavo-surface angles. -Classify cavity preparations according to the Black's Classification. A cavity is a defect in the hard tooth structure resulting from dental caries. This cavity is surgically opened to expose the carious lesion. 1
  2. 2. 04/11/34 Definition of Cavity Preparation Mechanical alteration of a tooth to receive a restorative material which will return the tooth and area to proper form, function, and esthetics Preparation procedure includes all defective and friable tooth structure Oper 1-2545 4 The carious material is removed and the cavity is given a form that will assure -proper retention for the restorative material. -adequate resistance to fracture during function. -immunity from recurrence of caries at the margins of the restoration -and protection for the vital pulp Areas of Liability to Caries: 1. Pits and Fissures: These are enamel defects or faults, which result from incomplete union of enamel lobes during formation of enamel. They are actual openings in which we can force an explorer or a probe and upon withdrawal, the explorer is met with resistance, food debris stagnate in these areas with subsequent fermentation and caries production. 2
  3. 3. 04/11/34 A fissure results from the incomplete union of two enamel lobes during the formative period of enamel. If complete union occurs between two enamel lobes, the result will be a groove. The explorer in this case will pass smoothly because there is no defect in the enamel. A pit results from the incomplete union of three enamel lobes during its formation, if complete union happens, the result will be a fossa. 2-Smooth surface caries: a-Areas in the proximal surfaces of teeth gingival to the contact area: Areas between two adjoining teeth is a place where food debris can stagnate and ferment the acid produced will decalcify enamel, where interproximal cavities occur. 3
  4. 4. 04/11/34 B-Areas below the greatest diameter of the tooth (buccal deflection ridge): Areas on the lingual and buccal or labial surfaces of teeth, below the area of greatest diameter, provide a shelter for food debris, where it collects, stagnates and ferments, thus producing caries. These are also smooth surfaces, as no pits or fissures are found. Classification of Cavities: 1. Baume’s classification considering the danger areas in teeth, cavities can be classified into: -Pits and fissures cavities. -Smooth surface cavities. 2. Black’s classification of cavities: The classification devised by G.V, black, which is based upon the site of onset of the carious process, and the relative frequency of the various sites involved, is most widely adopted. He classified cavities into five classes: 4
  5. 5. 04/11/34 Black ‘s classification of carious lesions which is still widely used in dental schools. However, this classification is now regarded as incomplete in that it does not include root caries and secondary caries. Also, it does not include non-carious lesions, which are treated in the same way as carious lesions. a) Class I Cavities: Are those cavities originating in anatomical pits and fissures. They are found in the occlusal surface of molars and premolars, the occlusal two-third of the buccal and lingual surfaces of molars and in the palatal surfaces of upper incisors. 5
  6. 6. 04/11/34 b) Class II Cavities: Are smooth surfaces lesions that occur in the proximal surfaces i.e., mesial or distal of molars and premolars. c) Class III Cavities: Cavities that occur in the proximal surfaces (mesial and distal) of incisors and canines (cuspids), but do not involve or include the incisal angle. d) Class IV Cavities: Cavities that originate on the mesial and distal surfaces of incisor and canine teeth, but caries is so extensive that the incisal angle is involved. Both class III and IV are smooth surface cavities, they differ only in the extent of caries, in class IV the caries is progressive and reaches the incisal angle while in classIII caries is limited to the proximal surface. 6
  7. 7. 04/11/34 e) Class V Cavities: Are smooth surface cavities occurring in the gingival third of the buccal and lingual surfaces of all teeth, excluding cavities occurring in anatomical pits in the palatal surfaces of upper incisors, where they are grouped with class I cavities. Class VI(Simon’s modification) cavities on the incisal edge of the anterior teeth or the occlusal cusp heights of posterior teeth. The walls,the line angle and the point angles of these cavity preparations are the same as those for the occlusal pit and fissure cavities. 7
  8. 8. 04/11/34 3- Sturdevant’s classification Cavities may be classified according to the number of surfaces affected by caries into: a) Simple cavities: Are cavities occurring in one surface only, e.g. simple occlusal, simple buccal, simple mesial, etc. b) Compound cavities: Are cavities involving two surfaces, e.g. occluso-mesial or distal, occluso-buccal or lingual, mesio- or disto-labial, mesio-palatal, etc. c) Complex cavities: Are cavities involving more than two surfaces e.g. mesio-occlusodistal, occluso-bucco-lingual, mesio-labio-palatal, etc. N.B.: Class I, II may be simple, compound or complex, while class V is always simple and class IV never be simple. Walls and Angle of Cavities: Black gave the following rules for naming the internal parts of cavities Rule I: The walls take the names of the adjacent tooth surfaces. Rule II: That wall of a prepared cavity, which is occlusal to the pulp, and in a plane at right angles to the long axis of the tooth, is called the pulpal wall or floor. In case the pulp of the tooth is removed, and the cavity thus extended to include the pulp chamber; that wall is called the sub-pulpal wall. 8
  9. 9. 04/11/34 Rule III: The wall which is parallel to the long axis of the tooth and approximates the pulp, is called the axial wall. Rule IV: All the angles are formed by the junction of two walls along a line, and are named by combining the names of the walls joining to form the angle. Rule V: All point angles are formed by the junction of three walls at a point, and are named by joining the names of the walls forming the angle. Definitions: The Cavo-Surface Angle: Is the angle formed by the junction of the wall of the cavity with the surface of the tooth. The cavo-surface angle of a cavity will be of enamel, in cavities present in the root of teeth, which are exposed due to gingival recession, the cavo-surface angle will be cementum. The enamel margin includes the whole outline of the prepared cavity 9
  10. 10. 04/11/34 The Dentino-Enamel Junction: Also called amelo-dental junction, is the line of junction of dentin and enamel as it appears in the walls of the prepared cavities. The Enamel Wall: Is that portion of a prepared cavity, which consists of enamel, It includes the thickness of the enamel from the dentino-enamel junction to the cavo-surface angle. The Dentin Wall: Is that portion of the wall of a prepared cavity, which consists of dentin. Pulpal Wall: The wall of the prepared cavity which is occlusal to the pulp and in a horizontal plane at right angle to the long axis of the tooth. Axial Wall: Any wall in the prepared cavity, which is parallel to the long axis of the tooth. 10
  11. 11. 04/11/34 THANK YOU 11

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