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Dental Handpieces and Accessories

Chapter Overview

  • Source: Robinson: Modern Dental Assisting, 14th Edition

  • Copyright: © 2024, Elsevier Inc. All Rights Reserved.

Learning Objectives

Lesson 35.1: Dental Handpieces and Accessories

  • Key Terms:

    • Pronounce, define, and spell key terms.

  • Importance of Rotary Instruments:

    • Summarize the role of rotary instruments in dental procedures.

  • Evolution of the Dental Handpiece:

    • Describe the historical development of dental handpieces.

  • Types of Dental Handpieces:

    • Discuss essential handpieces for restorative and aesthetic dentistry.

    • Identify and describe low-speed, high-speed, and laboratory handpieces, including their uses.

  • Specialized Handpieces:

    • Discuss additional specialized handpieces used in dentistry, including:

    • Ultrasonic handpiece

    • Laser handpiece

    • Air abrasion handpiece

  • Handpiece Maintenance:

    • Summarize the importance of maintaining handpieces.

    • Discuss the classification of handpieces as semi-critical instruments.

  • Rotary Cutting Instrument Role:

    • Describe the role and use of rotary cutting instruments in restorative dentistry.

  • Burs:

    • Define and detail the use and types of burs, including diamonds, finishing, abrasive, and laboratory burs.

Introduction

  • Rotary instruments attached to a dental handpiece operate at varying speeds to perform cutting, polishing, and finishing of tooth structures.

Evolution of Rotary Equipment

  • 1940s:

    • Introduction of rotary instruments and belt-driven handpieces, development of diamond cutting burs.

  • 1950s:

    • Invention of tungsten carbide, development of the air-driven turbine handpiece.

Dental Handpieces

  • Definition:

    • The dental handpiece is the most frequently used instrument in restorative dentistry, providing power for rotary instruments to cut or polish tooth structures and castings.

Low-Speed Handpiece

  • Speed Range:

    • Operates between 5,000 to 30,000 rotations per minute (rpm).

  • Movement:

    • Can operate in both forward and backward movements.

  • Attachments:

    • Features adaptations for:

    • Straight handpiece attachment

    • Contra-angle handpiece attachment

    • Prophy attachment

Uses of the Low-Speed Handpiece

  • Clinical Uses:

    • Removal of soft decay and fine finishing of cavity preparations.

    • Finishing and polishing restorations.

    • Coronal polishing and stain removal.

    • Adjustments of porcelain.

    • Root canal treatments.

  • Laboratory Uses:

    • Trimming and contouring temporary crowns.

    • Trimming and relining of removable partials and dentures.

    • Trimming and contouring orthodontic appliances.

Low-Speed Attachments

  • Types of Attachments:

    • Straight Attachments:

    • Used for long-shank laboratory burs and mandrels.

    • Contra-Angle Attachment:

    • Latch type and friction grip to hold rotary instruments.

    • Prophy Angle:

    • Utilized for polishing procedures, available in plastic disposable and metal variants.

High-Speed Handpiece

  • Design Features:

    • One-piece unit with slight curvature and air pressure operation.

    • Speeds up to 400,000 rpm with water-coolant systems and friction-grip locking for rotary instruments.

    • Equipped with fiber-optic lighting.

Uses of the High-Speed Handpiece

  • Clinical Uses:

    • Removal of decay and faulty restorations.

    • Tooth crown reduction for crowns and bridges.

    • Preparation of retention grooves for restorations.

    • Finishing or polishing restorations.

    • Sectioning teeth during surgical procedures.

Bur Locking Systems

  • Description:

    • Different from low-speed handpieces, using friction-grip devices.

    • Older models may require a bur-changing device, while newer ones may not.

Water Coolant System

  • Functionality:

    • Maintains optimal temperature during high-speed operation to prevent pulp damage.

    • Sprays water on tooth and bur for visibility and debris removal.

Fiber-Optic Lighting

  • Description:

    • Provides optimal lighting via light ports near the operating site improving visibility.

Laboratory Handpiece

  • Operational Speed:

    • Operates at up to 20,000 rpm, utilizing laboratory burs and offering greater torque than handpieces used intraorally.

Ultrasonic Handpiece

  • Main Use:

    • Primarily for scaling and root planing, designed to attach to the dental unit or self-contained supply.

    • Provides a pulsating water spray, powered by electricity.

Laser Handpiece

  • Functionality:

    • Employs laser light to cauterize soft tissue and vaporize decayed structure.

    • Offers painlessness and eliminates anesthesia wait time.

Precautions for Laser Handpieces

  • Best Practices:

    • Avoid sharp bends or twists of fiber-optic cables.

    • Keep the connecting parts clean for functioning efficiency.

Air Abrasion Handpiece

  • Description:

    • Functions similarly to a sandblaster, removes stains and decay using aluminum oxide particles delivered at high pressure.

  • Uses:

    • Preparation for sealants, external stain removal, and endodontic access.

    • Applicable in various cavity preparations without compromising healthy structures.

Handpiece Maintenance

  • General Considerations:

    • Use personal protective equipment and follow Universal Precautions.

    • Clean external debris, internal components, and ensure dry packaging before sterilization.

    • Sterilize and remove any lubricant from light ports with alcohol swabs.

  • Sterilization Procedure:

    • Follow specific instructions varies per manufacturer and model; sterilization sheets can prevent errors.

Rotary Cutting Instruments

  • Components:

    • Three main parts:

    • Shank: Fits into the handpiece; varies by type (straight, latch-type, friction-grip).

    • Neck: Connects the shank and head.

    • Head: Cutting, polishing, or finishing portion.

Dental Burs

  • Definition:

    • Rotary instruments featuring sharp cutting heads for various dental functions, including:

    • Preparing teeth, excavating decay, finishing cavity walls, and removing fillings.

Bur Shapes and Design

  • Shape Importance:

    • Refers to the contour or design of the bur's head; available in various shapes and sizes.

    • Each bur is identified by shape, size numbers, and intended purpose.

Cutting Burs Types

  • Examples:

    • Round Bur: For initial entry and caries removal (sizes 1/4, 1/2, 1-8, 10).

    • Inverted Cone: For caries removal and grooves (sizes 33 ½, 34-39, 36L, 37L).

    • Fissure Burs: Used for cavity prep walls, varied as straight or tapered.

Diamond Rotary Instruments

  • Application:

    • Commonly used for crown preparations with specific shapes like round and flat-end taper for tooth reduction.

    • Features various grits for distinct functions including polishing and adjustment.

Finishing Rotary Instruments

  • Characteristics:

    • Similar to cutting burs but with more blades for improved polishing and finishing capabilities.

Abrasive Rotary Instruments

  • Description:

    • Varied instruments using abrasive materials on multiple shapes, flexibility to match tooth contours.

Types & Functions of Abrasives

  • Common Instruments:

    • Rubber wheels for finishing, points for polishing, and stones for cutting and finishing restorations.

Accessory Attachments

  • Purpose of Mandrels:

    • Used to assemble abrasive discs/wheels with various handpiece shank types for both speed types.

Laboratory Rotary Instruments

  • Application:

    • Laboratory burs used primarily for trimming and polishing acrylics, with specific designs suited for use in low-speed handpieces.