Based on anatomical location of carious lesion, Greene Vardiman Black (G.V. Black) classified tooth preparations into five different classes. Later an additional class, class VI was also added. Class I refers to pit and fissure lesions, whereas all other classes are smooth surface lesions.
| Class I | 
All pit and fissure preparations. It Includes: 
➤ occlusal surfaces of premolars and molars, 
➤ occlusal two-thirds of the facial and lingual surfaces of molars, and ➤lingual surfaces of maxillary incisors 
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| Class II | |
| Class III | 
Preparations involving the proximal  surfaces of anterior teeth (incisors and canine) that do not include the incisal angle 
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| Class IV | 
Preparations involving the proximal surfaces of anterior teeth (incisors and canine) that include the incisal edge 
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| Class V | 
Preparations on the gingival third of the facial or lingual surfaces  of all teeth 
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| Class VI | 
Preparations on the incisal edges of anterior teeth  (incisors and canines) or the occlusal cusp tips of posterior teeth (premolars and molars) 
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