Dental Instruments and Their Uses

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Questions and Answers

Which of the following is a type of explorer commonly used in dentistry?

Straight explorer

Right angle explorer

Inter-proximal explorer

All of the above (correct)

What is the purpose of the serrated or angulated handle on an exploring probe?

To provide a comfortable grip. (correct)

To help with the precision of the probe.

To allow for easier sterilization.

To increase the strength of the probe.

Why is a single-ended explorer preferred over a double-ended explorer?

Double-ended explorers are harder to sterilize.

Single-ended explorers are more durable.

Single-ended explorers reduce the risk of accidental injury. (correct)

Double-ended explorers are more expensive.

What is the primary use of a periodontal probe?

To detect the depth of periodontal pockets. Signup and view all the answers

Which of these is NOT a method for isolating the operative field?

Using a periodontal probe. Signup and view all the answers

What is the primary purpose of a mouth mirror when used during an examination?

To provide direct vision of the tooth surfaces. Signup and view all the answers

Which of the following BEST describes the purpose of instruments used for removal of tooth substance?

To prepare the tooth for a restoration. Signup and view all the answers

Which of the following is NOT a hand-cutting instrument used to remove tooth substance?

Handpiece Signup and view all the answers

Which instrument is specifically designed for carving wax?

Discoid excavator Signup and view all the answers

Which chisel type is specifically designed for planning and cleaving enamel?

Straight chisel Signup and view all the answers

Which chisel type is used for defining line and point angles?

Mono-angle chisel Signup and view all the answers

Which chisel type has a slight curvature starting from the shank up to the cutting edge?

Wedel steadt chisel Signup and view all the answers

Which instrument is specifically designed for accentuating line and point angles in gold foil restorations?

Angel former Signup and view all the answers

Which instrument is a modified enamel hatchet and is used for trimming the gingival margin?

Gingival marginal trimmer Signup and view all the answers

Which of these instruments is used for carving amalgam?

All of the above Signup and view all the answers

What is the primary function of chisels in the context provided?

Planning of enamel undermined by caries or cutting away dentin Signup and view all the answers

Which of these bur types is primarily used for conservative cavity preparation, featuring a round end and a design capable of preparing the entire cavity?

245 or 330 bur Signup and view all the answers

What is the primary function of a finishing bur?

Finishing restorations Signup and view all the answers

What is the purpose of the clearance space between two successive blades on a bur?

To allow for the removal of cut dentin chips Signup and view all the answers

Which of the following is NOT a potential consequence of a too small clearance space between bur blades?

Increased cutting efficiency Signup and view all the answers

What type of bur shank is typically used for most dental procedures?

Regular shank Signup and view all the answers

What is the angle between the face and back of the same blade on a bur called?

Tooth or blade angle Signup and view all the answers

Which type of rake angle provides a very sharp blade but is considered too weak?

Positive rake angle Signup and view all the answers

What is the primary difference between a cutting bur and a finishing bur in terms of blade number?

Finishing burs have more blades than cutting burs. Signup and view all the answers

What is a major disadvantage of using air abrasion for tooth preparation?

It results in loss of tactile sensation. Signup and view all the answers

Why are lasers primarily used for soft tissue procedures?

They have harmful effects on hard tissues. Signup and view all the answers

Which of the following is NOT an advantage of sonic instruments?

They are highly efficient in cutting. Signup and view all the answers

What is the function of the blade in a hand cutting instrument?

To cut or cleave enamel and dentin. Signup and view all the answers

What is a common feature of all hand cutting instruments?

They are designed to be held in hand. Signup and view all the answers

What is a characteristic of a latch type handpiece?

Used with low speed Signup and view all the answers

What is Carisolv primarily used for?

To abrade carious dentin surfaces. Signup and view all the answers

Which of the following statements about enzymes like Pronase is true?

They help remove carious dentin effectively. Signup and view all the answers

Which handpiece is capable of reaching speeds over 800,000 rpm?

Airotor handpiece Signup and view all the answers

What is an important design feature of the shaft or handle of hand cutting instruments?

It must carry manufacturer and design information. Signup and view all the answers

In terms of speed, which category encompasses speeds below 12,000 rpm?

Low speed Signup and view all the answers

What advantage does high-speed handpiece offer to the operator?

Provides better control with less vibration Signup and view all the answers

What material is characterized by high hardness and can withstand heat generation without damage?

Tungsten carbide Signup and view all the answers

Which type of dental bur is primarily used for lateral extension of cavity walls?

Inverted cone bur Signup and view all the answers

Which feature distinguishes a straight handpiece from a contra-angle handpiece?

Shape of the handpiece Signup and view all the answers

What is a notable drawback of using steel burs compared to tungsten carbide burs?

Lower hardness and durability Signup and view all the answers

What is the primary factor influencing the cutting efficiency of a bur, making one type more efficient than another?

The type of bur material used Signup and view all the answers

Increasing the number of blades on a bur can enhance cutting efficiency, but what is a potential drawback?

Reduced clearance space, making it harder to access tight areas Signup and view all the answers

What is the primary reason why the inverted cone bur is considered significantly more efficient than a fissure bur of the same size?

The inverted cone bur has a smaller cutting area, allowing for more precise and efficient removal of tooth structure Signup and view all the answers

Which of the following is NOT a factor contributing to the increased cutting efficiency of tungsten carbide burs compared to steel burs?

Lower hardness number, resulting in a more aggressive cutting action Signup and view all the answers

What is the most suitable rake angle for bur blades, maximizing cutting efficiency while minimizing risk of fracture?

Zero rake angle Signup and view all the answers

Which of the following is NOT a consequence of using excessive pressure while cutting with a bur?

Improved cutting efficiency, removing more tooth structure per unit of time Signup and view all the answers

What is the primary reason why cross-cutting is only recommended for conventional speed burs and not high-speed burs?

High speed causes excessive vibration and heat generation, resulting in surface roughness with cross-cutting Signup and view all the answers

Which factor affecting the cutting efficiency of a bur is influenced by both the operator's actions and the size of the bur?

Pressure Signup and view all the answers

Study Notes

Instruments & Instrumentation

This document outlines instruments and instrumentation for Year 2 Operative Dentistry students at the British University in Egypt.
Operative instruments are categorized by function: isolation, exploration, tooth substance removal, restoration manipulation/packing/finishing/polishing, and miscellaneous instruments.

Isolation

Instruments used for isolation maintain a dry operative field, examples include rubber dams, saliva ejectors, and cotton roll holders.

Exploration

Instruments, that include explorers and mouth mirrors, are important for examining the operative field.
Single-ended explorers are preferred over double-ended to avoid injury.
Magnifying loupes, microscopes, and intraoral cameras are also used for enhanced exploration.
Exploring probes are used to identify caries, assess dentin consistency, and shape restorations.
Types of explorers include straight, right angle, inter-proximal, and arch explorers.
Periodontal probes aren't exploration tools but are used to measure periodontal pockets.

Tooth Substance Removal

Hand and powered instruments are used to remove tooth substance.
Powered instruments include rotary cutting instruments (e.g., burs and abrasive), air abrasion and lasers.

Rotary Instruments

Burs and abrasives are tools used for cavity preparation.
Air abrasion utilizes abrasive particles with an air stream to remove tooth structure.
Laser (waterlase) technology absorbs energy into the tooth to convert to heat for removal.

Advantages & Disadvantages of Air Abrasion

Advantages: minimal heat generation and painless procedure
Disadvantages: loss of tactile sensation and inability to create precise cavities

Advantages & Disadvantages of Lasers

Advantages: used for soft tissue
Disadvantages: harmful to hard tissues
Sonic instruments use abrasive particles but are safe against adjacent teeth

Chemo-Mechanical Methods

Carisolv gel is utilized with specialized non-cutting hand instruments to soften carious dentin. The softened dentin is then removed.

Enzymes

Pronase, a proteolytic enzyme, removes carious dentin.

Hand Cutting Instruments

Hand instruments are used to cut enamel and dentin, plan cavity walls, and shape restorations.
The instrument consists of a shaft/handle, shank, and blade.
Shaft/handle is serrated or angular to prevent slippage.
Shank connects the shaft to the blade.
Blade is the cutting portion.
Black's formula details instrument measurements on the shaft, including blade width, length, and angles.
Instruments are classified by type of use, direction of cutting, and number of bevels.

Instrument Types and Classification

Classified by use (excavators, chisels), direction of cut (direct or lateral), bevel type (single, double), number of ends (single or double), and contra-angling.

Excavators

Types include straight, mono-angle, bin-angle, triple-angle, and spoon excavators.
Used to remove soft carious dentin, shape internal cavity walls, and carve amalgam restorations.

Chisels

Common types include straight and modified chisels like mono-angle, bin-angle, and wedel.
Used for planning and cleaving enamel and cutting dentin.

Enamel Hatchet

Used to cleave enamel. A type of chisel.

Gingival Marginal Trimmer (GMT)

A modified hatchet for trimming gingival margins, used for axio-pulpal line angle refinement and cavity preparation

Instrument Grasps, Rests, and Guards

Rotary Cutting Instruments

Components include cutting points (burs and abrasives) and handpieces (latch and friction types).
Handpieces are categorized by speed (low, medium, high) and power source (electric or air).

Dental Cutting Burs

Classified by material (tungsten carbide or steel) and working head shape (rounded, inverted cone, fissure), blade number, length of shank, and shape.

Cutting Efficiency

Bur material, design (number of blades), and speed are key factors affecting efficiency.
Pressure affects the amount of friction, and factors like speed and cutting area influence the level of friction.
Higher cutting efficiency is seen with appropriate bur and speed.

Eccentricity or Run-Out

Maximum lateral displacement of a working instrument's point from its central axis is eccentricity.
The causes are defects in the tool, the attachment, the handpiece, or motor-handpiece junction.
Effects include vibrations, diminished cutting performance, increasing heat generation, and shortened bur life.

Heat Generation

Friction between the bur and tooth surface generates heat.
Pressure, speed, cutting area, cutting efficiency, and cutting time impact friction and heat generation.
Heat dissipation occurs in the bur, tooth, and formed chips and depends on the thermal conductivities.
Factors include pressure, speed, and cutting area.
High heat can cause problems like dehydration and burning to dentin and pulp, hyperemia, irreversible pulpal inflammation, and pulp shock.

Coolant

Coolant is vital to reduce heat buildup from high-speed instruments.
Coolants should be biologically compatible, maintain body temperature, and must be applied directly to the treatment area.
Coolant types include water, air spray, and air-water spray.

Dental Burs & Abrasives

Abrasives remove material differently than burs. They are used for cutting brittle materials like enamel and are more susceptible to clogging.
Burs are used differently, with different cutting characteristics, and less heat generation.

Instruments for Manipulation and Packing Restorations

Includes amalgam carriers, which have hollow ends to hold and place amalgam.
Condensers are used to pack and compact amalgam.
Plastic instruments are commonly used for handling composite materials.
Materials like gold-plated items or Teflon and zirconia are used to prevent composite stickiness.
Instruments are used for trituration through mortar and pestle action.
Amalgams and composite are mixed, and matrices and light curing units provide precision and hardening.

Shaping and Polishing Instruments

Burnishers: Used to smooth and polish amalgam or cast gold restorations.
Carvers: Shape amalgam and composite restorations.
Hand-held instruments: Include orange wood sticks or finishing strips for composite.
Rotary instruments: Include finishing burs, finishing stones, abrasive discs, and brushes.

Miscellaneous Instruments

Includes mouth mirrors, probes, pliers, and other auxiliary tools.

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Description

Test your knowledge on the various instruments used in dentistry and their specific functions! This quiz covers probing tools, explorers, chisels, and other essential instruments. Understand their designs and purposes in dental practice.