Porcelain Denture Teeth in Fixed-Bridge Construction A. H. Tamarin, D.D.S., Chicago
An original technic is presented for affix ing porcelain denture teeth to a bridge. These teeth can be replaced easily in case of breakage without damage to the bridge. In addition to this practical advantage, porcelain denture teeth improve the es thetic qualities of the restoration because of their pleasing, natural-like shape and appearance and because of the absence of gold on their incisal edges.
Anterior porcelain denture teeth produce esthetic and durable bridges. Separate backings must be constructed, cast and soldered together with the abutments. T h e backings must cover that portion of the tooth which is imbedded in the acrylic resin material when the tooth is used in denture construction. This cover age will maintain an equilibrium between power, fulcrum and weight, which is es sential to the security of the porcelain teeth. Should a tooth break, it can be re placed easily without damage to the bridge.
3. The wax is placed on the lingual surface of each porcelain tooth, and in dentations are marked on it to coincide with the necks o f the two metallic pins (Fig. 1).
(A ) with rectangular sheet of wax (B)
4. The thickness o f each pin neck is measured with a millimeter gauge, and two channels— each the size of a pin neck —are cut in the sheet o f wax. This pro cedure will admit the necks o f the pins into the two channels (Fig. 2,A ) .
T E C H N IC
T h e procedures used to affix the porcelain denture teeth to the bridge are as follows: 1. T h e linguogingival margin of each porcelain tooth is slightly beveled. 2. A rectangular portion of Kerr’ s hard, pink sheet-wax gauge no. 31 is cut to cover the entire gingival half of the lingual surface of each porcelain tooth.
Fig. 2 * Porcelain tooth (C ) with wax coverings (A, B.D)
68/828 • T H E J O U R N A L O F T H E A M E R IC A N D E N T A L A S S O C IA T IO N
5. T w o channels are cut in a similar rectangular sheet o f wax for the admis sion of the two pinheads (Fig. 2,B). 6. The two rectangular sheets of wax are placed over each other in their proper position on the lingual surface of the por celain tooth. They are then dipped to gether into a dish of warm water to
admission of the pins. A hot spatula is used to unite these three sheets of wax at their periphery. 8. Sprues are added to the triple lay ered wax backing and it is removed from the porcelain tooth, invested and cast. 9. After casting, the several gold back ings are placed on the porcelain teeth,
Fig. 3 • Pencil with flattened rubber end
soften them, after which they are adapted to the lingual surface o f the porcelain tooth with a lead pencil eraser which has been beveled especially for that purpose (Fig. 3 ). The surplus wax is trimmed, leaving a bent margin at the periphery o f the gingival border (Fig. 2 ,C ).
assembled and aligned. The backings are held in proper alignment by sticky wax applied to their lingual surfaces. The por celain teeth are removed. The backings and the bridge abutments are invested and soldered together (Fig. 4 ). 10. After soldering, the unit is cleaned and polished. The porcelain teeth are cemented into position and the bridge is ready for cementation into the patient’ s mouth. C O N C L U S IO N
Fig. 4 * Lingual appearance of porcelain bridge
7. A third rectangular sheet of wax cut to half the size of the former two sheets (Fig. 2,D) and placed on top of the others. This sheet of wax should cover the pinheads and pin necks as well as the channels which had been formed for the
By employing this technic, the use of stock porcelain denture teeth in fixed bridgework is practical because they can easily be replaced in case o f breakage. is Furthermore, porcelain denture teeth, be cause of their pleasing, natural shape and appearance and the absence of gold on their incisal edges, improve the esthetic qualities o f the restoration. 25 East Washington Street