Chapter 35 Dental Handpieces and Accessories

1. Chapter 35Dental Handpieces and Accessories Copyright 2003, Elsevier Science (USA) All rights reserved. No part of this product may be reproduced or transmitted in any form or by any means, electronic or mechanical, including input into or storage in any information system, without permission in writing from the publisher. PowerPoint® presentation slides may be displayed and may be reproduced in print form for instructional purposes only, provided a proper copyright notice appears on the last page of each print-out. Produced in the United States of America ISBN 0-7216-9770-4

2. Introduction Rotary instruments complete different functions in the cutting, polishing, and finishing of tooth structure and the restoration process.

3. The Evolution of Rotary Equipment • 1940s • Introduction of rotary instruments. • Belt-driven handpiece. • Development of diamond cutting burs. • 1950s • Invention of tungsten carbide. • Development of the air-driven turbine handpiece.

4. Dental Handpiece • Most frequently used piece of machinery in dentistry. The handpiece provides the power to a rotary instrument that completes the actual cutting or polishing of tooth structure and castings.

5. Low-Speed Handpiece • Design • Straight in appearance. • Standard length and “shorty.” • Speed ranges from 10,000 to 30,000 rotations per minute (rpm). • Operates the rotary instrument in either a forward or backward movement.

6. Fig. 35-2 Low-speed handpiece.

7. Low-Speed Handpiece-cont’d • Uses of the low-speed handpiece • Intraoral • Removal of soft decay and fine finishing of a cavity preparation. • Finishing and polishing of restorations. • Coronal polishing and removal of stains. • Extraoral • Trimming and contouring temporary crowns. • Trimming and relining of removable partials and dentures. • Trimming and contouring of orthodontic appliances.

8. Low-Speed Attachments • Straight attachment receives a long‑shank laboratory bur, the contra-angle attachment, and the prophy angle attachment. • Contra-angle attachment receives latch type rotary instruments and mandrel.

9. Low-Speed Attachments-cont’d • Prophylaxis Angle • Used during polishing procedures to hold the prophy cup and bristle brush. • Two types • Plastic disposable “prophy” angle • Metal “prophy” angle

10. High-Speed Handpiece • Design • One-piece unit with a slight curve in appearance. • Operates from air pressure. • Operates at speeds up to 450,000 rpm. • Maintains a water-coolant system. • Friction-grip locking system for rotary instruments. • Fiber-optic lighting.

11. High-Speed Handpiece-cont’d • Uses of the high-speed handpiece • Removes decay. • Removes an old or faulty restoration. • Reduces the crown portion of the tooth for the preparation of a crown or bridge. • Prepares the outline and retention grooves for a new restoration. • Finishes or polishes a restoration. • Sections a tooth during a surgery.

12. Ultrasonic Handpiece • Design • Attached to the dental unit. • Powered by electricity. • Attachments are similar in appearance to scaling instruments. • Delivers a pulsating spray of water.

13. Ultrasonic Handpiece-cont’d • Uses of the ultrasonic handpiece • Removes calculus. • Removes stain. • Removes bonding materials from a tooth surface after orthodontic appliances are removed. • Removes cement after orthodontic bands are removed.

14. Laser Handpiece • Design • Uses a laser light beam instead of rotary instruments. • The laser is conducted through a fiber‑optic cable. • Resembles a standard handpiece. • Maintains a water-coolant system. • Maintains an air-coolant system.

15. Laser Handpiece-cont’d • Uses: • Cauterizes soft tissue. • Vaporizes decayed tooth structure. • Advantages: • Usually painless. • Patient usually does not require anesthesia. • Proceed with procedure faster. • Disadvantage: • Cannot be used on teeth with existing restorations.

16. Air-Abrasion Handpiece • Design • Small version of a sandblaster. • Produces a high‑pressure delivery of aluminum oxide particles through a small probe.

17. Air-Abrasion Handpiece-cont’d • Uses • Prepares teeth for sealants. • Removes external stains. • Class I through class VI preparations. • Endodontic access. • Crown margins. • Prepares a tooth surface for the cementation of a cast restoration, such as a crown or veneer.

18. Laboratory Handpiece • Design • Operates at speeds up to 20,000 rpm. • Uses laboratory burs. • Provides greater torque than handpieces used intraorally.

19. Handpiece Maintenance • General considerations • Wear personal protective equipment and follow universal precautions. • Clean debris from the external surface. • Clean the internal components of the handpiece. • Handpiece must be dry before being packaged. • Wrap the handpiece for sterilization. • Sterilize the handpiece. • Wipe the light port on the fiber‑optic with an alcohol swab to remove any excess lubricant.

20. Rotary Cutting Instruments • Three basic parts to a rotary instrument: • Shank: Portion that fits into the handpiece. • Straight shank • Latch type shank • Friction grip shank • Neck: Portion of the rotary instrument that connects the shank and the head. • Head: The cutting, polishing, or finishing portion.

21. Fig. 35-12 Types of shanks.

22. Dental Burs • Rotary instruments that have a sharp cutting head. • Uses • Tooth preparation. • Excavation of decay. • Finishing cavity walls. • Finishing restoration surfaces. • Taking out old fillings. • Finishing crown preparations. • Separating crowns and bridges. • Adjusting and correcting acrylic temporaries.

23. Types and Shapes of Burs • Diamond rotary instruments areused for their cutting ability, which shortens preparation time and increases productivity. • Finishing rotary instruments: The more cutting surfaces on the head of a bur, the greater the polishing capability.