Modified class III cavity preparation

Date: 2015-10-07; view: 677.

Class III cavity

Carious lesions on the proximal surfaces of anterior primary teeth sometimes occur in children whose teeth are in contact and in children who have evidence of arch inadequacy or crowding. Carious involvement of the anterior primary teeth, however, may be interpreted as evidence of excessive caries activity requiring a comprehensive preventive program. If the carious lesion has not advanced appreciably into the dentin and removal of the caries will not involve or weaken the incisal angle, a small conventional class III cavity may be prepared and the tooth may be restored with the dentist's choice of bonding materials.

The distal surface of the primary canine is a frequent site of caries attack in patients at high risk for caries if the canine is in proximal contact with the first molar. The position of the tooth in the arch, the characteristically lingual and labial views of a modified class III preparation for a maxillary primary canine. The dovetail improves retention form of the preparation and allows access for placing the restorative material to ensure adequate contact with the adjacent tooth. Broad contact between the distal surface of the canine and the mesial surface of the primary molar, and the height of the gingival tissue sometimes make it difficult to prepare a typical class III cavity and restore it adequately. The modified class III preparation uses a dovetail on the lingual or occasionally on the labial surfaces of the tooth. A lingual lock is normally considered for the maxillary canine, whereas a labial lock may be more conveniently prepared on the mandibular teeth for which the esthetic requirement is not so important. The preparation allows for additional retention and access necessary to insert the restorative material properly.