Single Anterior Crowns
by Dr. Greg Janikian, D.D.S.
Single anterior crowns can be very challenging. Will the shade match? Will the tissue recede to expose a dark line at the gingival margin? Will the patient be happy? These are some the questions that go through our heads as we are preparing the tooth. All porcelain crowns offer a unique solution to the problem of shade match and gingival darkness associated with porcelain fused to metal crowns. The following is a case presentation of an full porcelain IPS Empress crown.
A 50 year old white male presents with a cosmetic concern. The tooth in question is the upper left central incisor (#9). After suffering a class IV mesioangular fracture #9 has undergone several cycles of bonding and rebonding. Upon examination the existing composite restoration was found to be failing in need of replacement. (Fig 1.) A full porcelain crown was recommended to strengthen the existing tooth structure and to provide a more cosmetic solution than bonding.
The area was anesthetized and an enamel shade was taken using an Ivoclair shade guide. Preparation of #9 consisted of removal of existing composite restoration and completion of a deep shoulder preparation. Reduction should be at least 1.5 to 2.0 mm to allow for adequate thickness in the final restoration. The gingival margin can be placed at the tissue level or slightly supragingival because there is no need to hide the margin. A dentin or "stump" shade was taken after preparation and impression. (Fig 2.) #9 was provisionalized with Triad and cemented with Temp Bond. (Fig. 3.)
Gold Dust dental lab, in Tempe, Arizona, fabricated the IPS Empress crown. They were provided with a pre-op photo to aid in fabrication. Note the translucency and the "stump" shade matrix used to perfect the shade of the Empress crown. (Fig. 4.) Also note the lack of metal and etched surface of the interior. (Fig. 5.)
Placement of IPS Empress crown consisted of removal of the provisional and try in of the crown to check marginal integrity and contacts only. Occlusion must be verified after cementation to prevent fracture. Placement of an all porcelain crown is very similar to that of a porcelain veneer. Both the tooth and the internal surface of the crown are etched. The internal surface of the crown is silainated and Porcelite resin bonding material placed to cover all internal surfaces while the tooth is treated with a bonding agent. The crown is placed on the tooth and excess bonding material removed with a brush. Curing for 30 seconds tacks the crown in place so the contacts can be flossed. After excessive curing (2 mins.) the margins are refined with a 30 fluted carbide bur to removed excess flash. Occlusion is then confirmed and adjusted if necessary. (Fig. 6.)
Metal inside a crown decreases translucency and reflects a dark gingival hue to the root. All porcelain crowns elevate our ability to provide patients with a very acceptable restoration and create the illusion of reality.