Provisional Coverage Chapter 51 1 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 1

Chapter 51 Lesson 51.1 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2

Learning Objectives Pronounce, define, and spell the Key Terms. Discuss the indications for provisional coverage for a crown or fixed-bridge preparation. Describe the types of provisional coverage. Discuss the dental assistant’s role in making a provisional crown or bridge. List home-care instructions for the patient with provisional coverage. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 3

Provisional Coverage Provisional coverage is a protective covering worn temporarily while a fixed prosthesis is being fabricated in the dental laboratory. What does the term provisional mean? How long can provisional coverage last? What is one example of a fixed prosthesis? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4

Purposes of Provisional Coverage Reduces sensitivity and discomfort of the prepared tooth Maintains the function and aesthetics of the prepared tooth Protects the margins of the preparation Prevents shifting of the adjacent or opposing teeth It is important for the dental assistant to know the normal anatomy of each tooth. What is a term used to describe the shifting of opposing teeth? (Supereruption.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5

Custom Provisional Coverage The most versatile provisional coverage for crown and bridge preparations Can be used for posterior or anterior crowns or bridges. Provides the best fit Most natural-looking Custom provisional coverage is designed specifically for the needs of each patient. Different shades of acrylic are available. Which teeth would benefit most from the shaded acrylic? Why? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 6

Fig. 51-1 Custom provisional coverage. Which tooth is involved? Notice the anatomy that has been trimmed into the temporary coverage. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 7

Criteria for Constructing Provisional Coverage The coverage is aesthetically acceptable to the patient The contours are similar to those of the natural tooth. The cervical margin is smooth and fits snugly. Coverage must not extend below the margin of the preparation. The occlusal surface is aligned with the occlusal plane of the adjacent teeth. When cemented, the provisional coverage remains stable, stays in place, and is comfortable for the patient. The provisional coverage can be easily removed without damage to the tooth or adjacent tissues. What does the margin look like on a prepared tooth? Why are aesthetics an important consideration for the patient? What is the provisional coverage cemented with? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 8

Preformed Polymer Crowns Provisional shell-like crowns are designed specifically for premolars and molars. Shells are made of a polymer material designed with the anatomic features of natural teeth. Preformed polymer is available for single crowns and bridgework. Composite resin bonds with preformed crown to preparation. Does this type of provisional coverage require a preliminary impression? Can shaded acrylic be used? Why or why not? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 9

Fig. 51-2 Preformed polymer crown. Notice that the anatomy of this temporary was preformed. Little adjustment is necessary to add anatomic details. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 10

Aluminum Crowns Aluminum crowns are designed specifically for premolars and molars. Such crowns are available in a range of sizes for posterior teeth. Surfaces may be anatomic or nonanatomic. The crown is sized, contoured, and cemented in place. Why are aluminum crowns not used on anterior teeth? These crowns can be lined with acrylic for a more customized fit. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 11

Preformed Polycarbonate Crowns Tooth-colored crowns are selected for anterior teeth, where appearance is important. Available in a variety of sizes, shapes, and shades. Easily adapted to margins. Suitable for short- or longer-term use. Preformed polycarbonate crowns are commonly used in cases involving fracture of an anterior tooth. As a result of the missing tooth structure, no preliminary impression can be taken. These crowns have easy-grab tabs and are easily adjusted. They can be lined with acrylic for a better fit. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 12

Fig. 51-4 Preformed polycarbonate crowns. Several options can be tried. Can a preformed polycarbonate crown be disinfected after try-in? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 13

Home-Care Instructions for Provisional Coverage Bite and chew carefully, and avoid sticky foods. When flossing, do not “pop” the floss in and out of contact. Once the floss is placed below the contact, pull it through. If the provisional covering is loose or lost, contact the office immediately to have it recemented. What are some examples of sticky foods? (The dental assistant should always give examples of foods the patient should avoid.) Give oral and written directions to patient. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 14