Intracrown ring for crown and fixed partial denture abutments

When a tooth prepared for a crown does not comply with the general principles of retention and resistance form, and it is not possible to correct it without damage to the biologic structures of the tooth, consideration must be given to the purpose of the crown, such as whether it is a single crown, a retainer for a fixed restoration, or a retainer for a fixed removable prosthesis with precision attachments. The crown prepared with receptacles for internal attachments will undoubtedly require more retention and resistance to dislodgment than a single crown because of forces that will be applied to it through the removable portion of the restoration. The purpose of this article is to present an alternative procedure that uses the intracrown ring, which provides additional retention for the abutment crown because of the compressible ring. The compressible ring is placed in the groove prepared in the lower third of the abutment during the crown preparation.