Conservative approach to the placement of retentive pins

A thorough understanding of the basic principles of cavity preparation and knowledge of tooth morphology are necessary for the successful positioning of pin channels in the tooth. Sufficient dentin surrounding the channel is necessary for adequate strength, to avoid external fractures of tooth structure and to protect the pulp. Once the channel location is decided upon, it should be made parallel with the external surface of the tooth rather than its long axis. It is suggested that the operator use only one pin per missing cusp of the tooth and that where possible this pin be placed in the area of the line angles. Optimal length of the pin into the restorative material is 2 mm and in the dentin is 2 to 3 mm for those retained by dentinal elasticity and 3 to 4 mm for those retained by cement. The use of a rubber dam for isolation procedures is encouraged, as well as radiographs and diagnostic casts to aid in the successful placement of retentive pins.