Essentials of. Dental Assisting. Edition 6. Debbie S. Robinson Doni L. Bird

Transcription

1 Essentials of Dental Assisting Edition 6 Debbie S. Robinson Doni L. Bird

2 CHAPTER21 Restorative Procedures LEARNING OBJECTIVES KEY TERMS 1. Pronounce, define, and spell the key terms. 2. Define restorative dentistry and esthetic dentistry and discuss dental conditions requiring both types of treatment. 3. Describe the process and principles of tooth preparation. 4. Give the importance of the matrix system for Class II, III, and IV restorations, and demonstrate the following procedures: Assemble a matrix and universal retainer. Place a plastic matrix for a Class III or Class IV restoration. Place and remove a matrix and wedge for a Class II restoration. 5. Discuss permanent and complex restorations, and describe the procedures of both an amalgam and a composite restoration. 6. Describe veneers. 7. Describe vital bleaching. cavity esthetic dentistry matrix operative dentistry Restorative dentistry, also referred to as operative dentistry, is an integral part of the general dental practice. This chapter introduces the background knowledge and preparation restorations restorative dentistry veneer vital bleaching wedge describes the techniques necessary for the clinical dental assistant to be better prepared when assisting with restorative procedures in a general dental practice. Responsibilities of the Dental Assistant in a Restorative Dental Procedure Preparing the tray setup, paper products, and dental Assisting in moisture control (see Chapter 10) materials Assisting in the removal of decay (see Chapter 19) Knowing and understanding the sequence of a specific Assisting in the placement of dental materials (see procedure Chapter 20) Having the ability to anticipate the dentist s needs Maintaining patient comfort and appropriate exposure Assisting in the examination of the tooth or teeth (see control precautions Chapter 12) Performing legally permitted delegated expanded Assisting in the administration of local anesthesia (see functions Chapter 14) 334

3 Restorative dentistry is indicated when teeth are to be restored to their original structure with the use of direct and indirect restorative dental materials. The common types of procedures include amalgam restorations, composite resin restorations, and complex restorations. Dental Conditions Requiring Restorative Dental Treatment Management and treatment of carious lesions by restoring them with a permanent restoration Restoration of defects in tooth structure Replacement of failed restorations Abrasion or wearing away of tooth structure Erosion of tooth structure Esthetic dentistry is directed on improving the appearance of teeth by restoring imperfections with direct and indirect restorative materials or with the use of whitening techniques. The common types of procedures are composite resin restorations, resin veneer restorations, and tooth whitening. Dental Conditions Requiring Esthetic Dental Treatment Discoloration attributable to extrinsic or intrinsic staining Anomalies caused by developmental disturbances Abnormal spacing between teeth Trauma Cavity Preparation Regardless of the type of dental material selected, understanding the steps of a restorative procedure is important. The steps include removal of the decay by the dentist, preparation of the tooth cavity, placement of dental materials, and finishing the restoration. The most detailed part in restoring a tooth is the cavity preparation. The purpose of cavity preparation is to remove the decay along with a small amount of healthy tooth structure, which, when completed, provides a solid foundation for the restorative dental material to be placed as a final restoration. To understand the different types of tooth preparations, you can review the types of cavity classifications in Chapter 12. The dentist will use a high-speed handpiece with a variety of burs and hand instruments to accomplish this preparation step. Once the decay is removed, the dentist will use the highspeed handpiece with a different-shape bur to place retentive grooves in the preparation. These small grooves in the tooth allow the material to flow into the groove area, harden, and create the retentive result. In the next step, the dentist determines the type of restorative material that will be used. This decision is based on the size, shape, and location of the preparation. With small preparations, an amalgam or composite material can be directly placed over sound dentin. With deeper preparations, a cavity liner, base, and FIGURE 21-1 Matrix and wedge correctly positioned. FIGURE 21-2 Assortment of wedges. (Courtesy Premier Dental Products Company, Plymouth Meeting, Pennsylvania.) bonding material may be required before the amalgam or composite is placed. Matrix Systems A tooth that is to receive a Class II, III, or IV restoration will have a minimum of one interproximal wall or surface of the tooth removed during the cavity preparation stage. By including the use of a matrix system, a temporary wall is created, against which the restorative material is placed until the material has set. The universal retainer and matrix is the system most commonly used when placing posterior restorations (Figure 21-1). The retainer firmly holds the matrix in place. A matrix is a metal or clear plastic used to replace the missing proximal wall of a tooth during placement of the restorative material. (Matrix is singular. The plural form is matrices.) Clear plastic matrices are used for anterior composite restorations. A wedge is triangular or round and is supplied in wood or plastic (Figure 21-2). The wedge is available in different sizes, depending on the location and space between the teeth. By CHAPTER 21 Restorative Procedures 335

4 Universal Occlusal edge Gingival edge Extension Occlusal edge Gingival edge FIGURE 21-3 Assorted matrix s. placing a wedge, the proper anatomic contour of a restoration is created. Posterior Matrix System The matrix and universal retainer should be assembled before the procedure to save time during the procedure. Matrix Bands Matrix s selected for Class II posterior restorations are made of a flexible stainless steel and are available in universal and extension sizes. The wraps around the tooth, creating a temporary wall (Figure 21-3). Before the and the retainer are assembled, the should be contoured in the proximal area so the tooth can Components of a Universal Retainer 1 Spindle pin (stabilizes in holder) 2 Outer slot to hold position of 1. Spindle: This internal screwlike pin fits into the diagonal slot to hold the ends of the matrix. When the retainer is assembled, the spindle point must be clear of the slot while the is slid into the slot and then tightened. 2. Outer guide slots: Also known as guide channels, these slots are located at the end of the retainer and FIGURE 21-4 Burnishing the matrix will provide a better contour. (From Heymann HO, Swift EJ, Ritter AV: Sturdevant s art and science of operative dentistry, ed 6, St. Louis, 2013, Mosby.) make proper contact with the adjacent tooth (Figure 21-4). To contour the, place the on a paper pad, using a burnisher or handle end of cotton pliers. Rub the inner surface of the until the ends begin to curl. This thins the and provides a normal curvature of the to fit around the tooth. Universal Retainer The universal retainer, also referred to as Tofflemire retainer, is a device that holds the matrix in position. The components of the universal retainer are described in the box titled Components of a Universal Retainer. See Procedure 21-1: Assembling a Matrix Band and Universal Retainer. 5 Diagonal slot to receive ends of 3 4 Outer knob Inner knob serve as channels to guide the loop of the matrix. The channel selected is determined according to the quadrant that is being treated. 3. Outer knob: The outer knob is used to tighten or loosen the spindle within the diagonal slot and to hold the matrix securely in the retainer. To tighten the 336 PARTEight Restorative Dentistry

5 Components of a Universal Retainer cont d spindle, turn the outer knob away from you. To loosen the spindle, turn the outer knob toward you. Be careful not to turn it too far, or the diagonal slot vise will fall off the spindle. If this happens, then insert the end of the spindle into the diagonal slot vise, and turn the outer knob away from you. 4. Inner knob: The inner knob is used to increase or decrease the size of the matrix loop. The size of the From Bird DL, Robinson DS: Modern dental assisting, ed 11, St. Louis, 2015, Saunders. Anterior Matrix System A clear plastic matrix strip is the matrix of choice for Class III and IV anterior restorations. Composite resins have inorganic filler particles that could be scratched or marked if a stainless steel matrix system were used. The plastic matrix strip is supplied already contoured or as a clear flat strip that is contoured (rounded) to adapt to the shape of the tooth. To contour the strip, pull it lengthwise over the handle of a mouth mirror (Figure 21-5). The strip is placed interproximally (between the teeth) before etching the tooth and before the placement of the restorative material. The strip is then tightly pulled around the tooth to adapt the composite to the natural contour of the tooth. The matrix is held in place by hand or with a retainer clip until the composite is hardened from the light-cured process. See Procedure 21-2: Placing a Plastic Matrix for a Class III or Class IV Restoration (Expanded Function). Wedges Wedges are used for all Class II, III, and IV matrix systems. A wedge is placed into the embrasure to hold the matrix firmly against the gingival margin of the preparation (Figure 21-6). This placement allows the dentist to carve the restorative dental material back to the original normal contour with proximal contacts of the tooth. If the contact is not there, then the tooth could slightly drift, allowing food to impact the area, creating problems for the patient. loop formed by the depends on the tooth to be restored. When the is placed over the tooth, the size of the loop circumference should be larger than the tooth, and the should be tightened after placement. 5. Diagonal slot: This slot is within the boxlike structure and is used to position the ends of the matrix into the vise; the retainer is always positioned in the mouth with the diagonal slot facing toward the gingiva. Cotton pliers or Howe pliers are used to place the wedge firmly into the embrasure. If a universal retainer is used, then the retainer is situated from the buccal side of the tooth and the wedge is inserted from the lingual side. See Procedure 21-3: Placing and Removing a Matrix Band and Wedge for a Class II Restoration (Expanded Function). Permanent Restoration A permanent restoration can range from a small Class I restoration to an extensive Class II multisurface foundation. With the exception of steps added to the procedure by using supplementary accessories and dental materials, a restorative procedure will follow a standardized format. The assistant will communicate with the patient about the procedure and what to expect during treatment. The assistant will correctly position the patient for the dentist and specific area of the mouth. A Incorrect B Correct FIGURE 21-5 Contouring a plastic matrix. (From Heymann HO, Swift EJ, Ritter AV: Sturdevant s art and science of operative dentistry, ed 6, St. Louis, 2013, Mosby.) C Incorrect FIGURE 21-6 Proper placement of wedges. (From Heymann HO, Swift EJ, Ritter AV: Sturdevant s art and science of operative dentistry, ed 6, St. Louis, 2013, Mosby.) D Correct CHAPTER 21 Restorative Procedures 337

6 FIGURE 21-7 Placement of a retention pin for added internal strength. The dentist will evaluate the tooth to be restored. The dentist will administer local anesthesia (see Chapter 14). The assistant will prepare and assist in the type of moisture control (cotton roll, dry angles, dental dam) to be used for the procedure (see Chapter 10). The dentist will prepare the tooth, including using dental hand instruments and dental handpieces with rotary instruments (see Chapter 19). The dentist will specify which dental materials are to be used (see Chapter 20). The assistant will prepare and assist in the placement of the dental materials. The assistant will prepare and assist in checking the occlusion. The dentist will finish and polish the restoration. See Procedure 21-4: Assisting in a Class II Amalgam Restoration, and Procedure 21-5: Assisting in a Class III or IV Composite Restoration. Complex Restorations If the loss of tooth structure is greater than the remaining natural tooth, then the dentist must decide whether to (1) move ahead and restore the tooth with an amalgam or a composite material, or (2) change the treatment plan and replace the tooth structure with a cast restoration. Bonding techniques and retention pins are best suited for use in teeth that require very large restorations with little tooth structure remaining to provide strength and retention for the amalgam. Retention pins provide internal strength to the placed material (Figure 21-7). These pins are available in a variety of diameters (widths) and styles to fit all sizes of teeth. Because all retention pins are very small (approximately one half the size of a bur) and are easily dropped, the dental dam should be indicated for this procedure. Veneers A veneer is a thin layer of tooth-colored material that can be directly bonded onto the tooth or fabricated in the laboratory FIGURE 21-8 Veneers placed on teeth #8 and #9 to reduce discoloration and to cover stain. A, Before placement. B, After placement. (From Heymann HO, Swift EJ, Ritter AV: Sturdevant s art and science of operative dentistry, ed 6, St. Louis, 2013, Mosby.) A B using a porcelain material and then cemented to the tooth surface (Figure 21-8). Veneers are used to improve the appearance of teeth that are slightly abraded, eroded, or discolored from stains or from endodontic treatment. Veneers can also be used to improve the alignment of teeth or to close a diastema. Vital Bleaching Vital bleaching, also referred to as tooth whitening, is a technique that involves the whitening of the external surfaces of the teeth. This desired whitening is completed for esthetic purposes, not for restorative purposes (Figure 21-9). 338 PARTEight Restorative Dentistry