Dental Hand Instruments
Learning Objectives
Key Terms: Pronounce, define, and spell critical terms related to dental instruments.
Importance of Knowledge: Summarize why identifying dental instruments is essential for procedures.
Function of Dental Instruments: Describe the intended use of a dental instrument.
Components of Instruments: List the three specific parts that make up a dental instrument.
Additional Objectives
Classify instruments utilized in general dental procedures.
Explain the theory behind arranging instruments in a particular sequence.
Identify and articulate the uses of various dental instruments:
Examination Instruments
Hand (Manual) Cutting Instruments
Restorative Dental Instruments
Accessory Instruments
Discuss the utilization of preset trays, tubs, and color-coding systems in dental practice.
Examine the use of storage tubs for procedural items and justify the rationale behind color coding for organizational purposes.
Introduction to Dental Instruments
A broad spectrum of dental instruments is used in contemporary dentistry.
Dental supply companies manufacture numerous variations of instruments tailored to accommodate personal preferences of dental professionals.
Identifying Hand Instruments
Instrument Identification: Dental manufacturers typically assign a number to most instruments.
Dentists often refer to pliers and forceps using their assigned numbers instead of their names.
It is advantageous to learn both the numerical and the descriptive nomenclature of each instrument.
Instrument Design
Three Specific Parts:
Handle: The part of the instrument that the operator grasps.
Shank: The connector between the handle and the working end of the instrument.
Working End: The designed portion for specific functions—can be a point, blade, or nib.
Basic Structural Parts
Working End: Can vary in design based on the intended function (e.g., point or blade).
Handle: Can be round, hexagonal, smooth, or serrated depending on design preferences.
Shank Angles:
Monangle: Single angled (1 angle).
Binangle: Double angled (2 angles).
Triple Angle: Three angles.
Black’s Instrument Formula
Formula Explanation: Black designed a formula that outlines the angulations and dimensions of a hand instrument’s working end.
Three Sets of Numbers Relating to Hand Cutting and Scaling Instruments:
Width of Blade: Determined by the first number.
Length of Blade: Given by the second number.
Angle of Blade: Defined by the third number in relation to the handle.
Specifics of the Formula
Example for understanding numbers in Black's formula:
First Number: Width measured in tenths of millimeters (e.g., a number 10 indicates a width of 1 mm).
Second Number: Length in millimeters (e.g., a number 7 indicates a length of 7 mm).
Third Number: Angle in degrees relative to the handle (e.g., a number 90 means a right angle at 90 degrees).
Instrument Sequence
Setup Protocol: The procedure tray is organized from left to right.
Instruments are arranged based on their use frequency, making the most frequently needed instruments closer to the dentist for ease of access during procedures.
Classification of Instruments
Types of Instruments
Examination Instruments: Frequently used for various tasks ranging from checking specific issues to conducting thorough oral examinations and evaluating restored teeth.
Hand (Manual) Cutting Instruments: Placed next on the tray setup following examination instruments. Their selection can vary based on dentist preferences and the type of procedure.
Restorative Instruments: These are designated for placing, condensing, and sculpting restorative materials, tailored to match the dentist's choices and the materials used.
Accessory Instruments: Not typically included in the primary tray setup but available as needed for various procedures, adherence to infection control protocols regarding disinfection or sterilization is essential whenever these instruments are utilized.
Setup for Basic Procedures
Essentials on every tray include:
Mouth Mirror: Utilized for indirect vision.
Explorer: Used to detect cavities or other irregularities in teeth.
Cotton Forceps (Pliers): Shaped like tweezers, used to manipulate dental materials.
Best Order of Placement: Recommended to position the explorer first and the mirror second on the tray.
Examination Instruments in Detail
Types and Functions:
Mouth Mirrors: Essential for indirect vision and illumination in the mouth.
Explorers: Single or double-ended instruments that are thin, sharp, and flexible, employed to examine teeth for irregularities.
Cotton or College Pliers: Function similarly to tweezers for placing and removing various items from the oral cavity.
Periodontal Probes: Utilized to measure the depth of the gingival sulcus and assess periodontal health.
Restorative Instruments
Functionality: Used for placing, condensing, and carving restorative dental materials to replicate the tooth's natural anatomy.
Selection: Instruments vary based on the dentist's choices and the type of materials to be utilized in the procedure.
Hand (Manual) Cutting Instruments
Next instruments included after examination tools—preferences vary between dentists,
Types include:
Chisels: Used for shaping and planning enamel and dentin walls;
Hatchets: Designed to refine cavity walls and provide retention during cavity preparation;
Hoes: Used for smoothing and shaping cavity floor preparations;
Gingival Margin Trimmers: Designed with curved blades for beveling gingival margins in cavity preparations;
Angle Formers: Used for defining angles in cavity preparations;
Excavators: Spoon-shaped instruments for removing carious materials, packing retraction cords, and tucking rubber dams.
Non-Cutting Instruments
Include:
Plastic Filling Instruments: Used for placing and condensing restorative materials.
Composite Instruments are similar but designed to prevent discoloration of materials.
Amalgam Carriers: For carrying and dispensing amalgam.
Amalgam Condensers: For packing amalgam.
Carvers: Used for removing excess material and carving dental anatomy into restorations.
Burnishers: To smooth rough edges and shape matrix bands.
Files: For trimming filling materials.
Finishing Knives: For finishing excess material.
Miscellaneous Instruments: Spatulas, articulating forceps, scissors, which serve various supplemental functions.
Accessory Instruments and Items
Accessory instruments are supportive and may be pulled as needed during procedures.
Proper infection control protocols must be followed regarding disinfection and sterilization before returning them to storage.
Care and Maintenance of Instruments
Proper care and maintenance techniques enhance the lifespan of dental instruments:
Follow strict cleaning and sterilization protocols.
Conduct thorough examinations of all instruments to ensure functionality and cleanliness.
Preset Cassettes (Trays)
Instruments and accessories are prepared, stored, and transported as a unit for specific procedures (e.g., examination, hygiene, restorative, crown and bridge, and surgical procedures)
Color-Coding Systems
An efficient method to organize instruments and supplies for specific procedures:
Instruments, trays, and storage tubs can be color-coded for ease of identification and use in dental practices.
Dental Handpieces and Accessories
Lesson 35.1: Dental Handpieces and Accessories
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.
Straight Plane - 55-60,57L, 58L
Straight Crosscut - 556-560, 567L,568L
Tapered - 169-172, 169L, 170L, 171L
Tapered Crosscut - 699-703, 699L, 700L,701L
End Cutting: 957, 958
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.