Dental Instruments for Year 2 Dentistry Students

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Questions and Answers

Which instrument is specifically designed for trimming the gingival margin?

Discoid excavator

Gingival marginal trimmer (correct)

Spoon excavator

Cleoid excavator

What is the primary function of a straight chisel?

Planning and cleaving enamel (correct)

Removing enamel rods with a push action

Carving amalgam

Defining line and point angles

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

Bin-angle chisel

Mono-angle chisel

Wedel steadt chisel

Angel former (correct)

What is the fourth number in Black's formula used for?

The angle of the cutting edge from the long axis of the shaft. Signup and view all the answers

What is the difference between a straight chisel and a Wedel steadt chisel?

The Wedel steadt chisel has a slight curvature, while the straight chisel is completely straight. Signup and view all the answers

What is the primary function of a chisel?

Cutting and separating enamel and dentin. Signup and view all the answers

Which instrument is most commonly used for carving amalgam in anterior teeth?

Discoid excavator Signup and view all the answers

What is the primary difference between a mono-angle chisel and a bin-angle chisel?

The mono-angle chisel has one angle in the shank, while the bin-angle chisel has two. Signup and view all the answers

Which of the following is NOT an advantage of carbon steel instruments?

Corrosion resistance Signup and view all the answers

Which instrument is used for removing enamel rods with a push action?

Bin-angle chisel Signup and view all the answers

What is the purpose of contra-angling in hand cutting instruments?

To improve the balance and accessibility of the instrument by bringing the working end closer to the handle. Signup and view all the answers

What distinguishes the Angel former from other chisels?

It has a triple beveled blade. Signup and view all the answers

Which of the following is a characteristic of a single-beveled instrument?

It has a bevel on only one side of the blade. Signup and view all the answers

Which type of hand cutting instrument is best suited for excavating soft carious dentin?

Excavator Signup and view all the answers

What is the difference between direct cutting and lateral cutting?

Direct cutting uses a single plane of force while lateral cutting uses multiple planes. Signup and view all the answers

Which of these is NOT a type of contra-angle?

Straight Signup and view all the answers

What is the main advantage of using high-speed handpieces in dentistry?

They are more efficient for removing tooth structure with less pressure and vibration. Signup and view all the answers

Which type of dental bur is known for its high hardness number and resistance to heat generation?

Tungsten carbide burs Signup and view all the answers

What is the primary function of an inverted cone bur in dentistry?

Creating retention in cavity walls. Signup and view all the answers

Identify a characteristic NOT associated with a straight handpiece used in dentistry.

Offers a broader range of speeds compared to contra-angle handpieces. Signup and view all the answers

Which of the following is NOT a speed range commonly associated with dental handpieces?

Super-high speed (above 1,000,000 rpm) Signup and view all the answers

What is a major difference between airotors and electric motors used in dental handpieces?

Airotors are more powerful than electric motors. Signup and view all the answers

What is the primary purpose of a rounded bur in dental procedures?

Creating retentive grooves and pinholes in tooth preparations. Signup and view all the answers

Which one of the following is a significant disadvantage associated with Tungsten Carbide burs?

They are prone to chipping and breakage. Signup and view all the answers

What type of bur is primarily used for conservative cavity preparation and has a round end?

245 or 330 bur Signup and view all the answers

What is the main advantage of a bur with a latch type shank?

Compatibility with ultra-speed Signup and view all the answers

Which of the following statements about the clearance angle is true?

It is the angle between the back of the blade and the work surface Signup and view all the answers

What is the function of the clearance space between two successive blades?

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

How many blades does a cutting bur typically contain?

6-8 blades Signup and view all the answers

Which bur type is mainly utilized for finishing line in crown and bridge work?

End cutting bur Signup and view all the answers

What characterizes the rake angle (R.A) of a bur's blade?

It affects cutting efficiency Signup and view all the answers

In which situation would a long shank bur specifically be utilized?

For surgery work Signup and view all the answers

What effect does a positive rake angle have on cutting efficiency?

It improves cutting efficiency but may lead to blade fractures. Signup and view all the answers

Which factor does NOT affect the cutting efficiency of a bur?

Operator's clothing Signup and view all the answers

Among the following, which material has the highest cutting efficiency?

Tungsten carbide Signup and view all the answers

What happens to cutting efficiency if the number of blades on a bur is increased?

It will generally increase within certain limits. Signup and view all the answers

Which type of bur is more efficient at cutting dentin?

Inverted cone bur Signup and view all the answers

What is the impact of increased pressure on a bur's cutting efficiency?

It increases both cutting efficiency and heat generation. Signup and view all the answers

What is the primary advantage of a zero rake angle for a bur?

It balances cutting efficiency and blade integrity. Signup and view all the answers

What is the formula for calculating pressure applied by a bur?

P = F / A Signup and view all the answers

Which of the following is NOT a function of coolant in dental procedures?

Reduces the need for local anesthesia Signup and view all the answers

What makes air-water sprays the most effective type of coolant?

They provide the best combination of humidity control and dentin hydration Signup and view all the answers

Which of the following is a characteristic that distinguishes diamond points and stones from dental burs?

They are primarily used for abrasion rather than cutting Signup and view all the answers

Which type of cutting instrument is most effective for cutting enamel?

Diamond points Signup and view all the answers

Why is copious coolant essential when using diamond points and stones?

To prevent clogging of the abrasive particles and reduce heat generation Signup and view all the answers

What is the primary difference in application between carbide burs and diamond points or stones?

Carbide burs are used for intracoronal preparations while diamond points and stones are used for extracoronal preparations Signup and view all the answers

What is the purpose of an amalgam carrier?

To hold and transport amalgam increments to the preparation site Signup and view all the answers

Which of the following is NOT a characteristic of rotary cutting instruments?

They are all made from diamond or carbide materials Signup and view all the answers

Study Notes

Instruments & Instrumentation

The document details instruments and instrumentation for year 2 dentistry students.
Instruments are classified by function for isolation, exploration, tooth removal, restoration manipulation, shaping, finishing, and polishing.
Isolation instruments include rubber dam, saliva ejectors, and cotton roll holders for maintaining a dry operative field.
Exploration instruments involve mirrors, explorers (single-ended preferred), magnifying loups, microscopes, and intraoral cameras for examining the operative area.
Exploration Probes: Composed of a handle, shank, and exploring tip, used to detect caries, and determine the consistency of carious dentin.
Periodontal probes are used to measure pocket depth and instrument dimensions, unlike explorers.
Removal instruments include hand cutting and powered instruments (rotary, air abrasion, laser).
Rotary cutting instruments (Burs & abrasive) are used for cavity preparation.
Air abrasion uses an air stream with abrasive particles (Aluminum oxide) for tooth structure removal via abrasion.
Laser (waterlase) absorbs energy & converts it into heat for destruction/necrosis via evaporation (ablation).
Sonic instruments use abrasive particles for cutting, injury to adjacent teeth prevention.
Chemo-mechanical methods (Carisolv) use a gel applied with non-cutting hand instruments to abrade carious dentin, leaving a hard, caries-free cavity.
Enzymes (Pronase) are proteolytic enzymes used to remove carious dentin.
Hand cutting instruments are used to cut or cleave enamel/dentin for cavity wall planning.
Black's formula details measuring instrument measurements written on the shaft's center: width, length, angles.
Instrument materials: Stainless steel (corrosion resistant, less cutting efficiency) and Carbon steel (corrosion resistant, good cutting efficiency, brittle).
Hand cutting instruments are classified by use (excavators, chisels); cutting direction (direct, lateral); beveling (single, bi, triple); ends (single, double); and contra-angling (angle to the handle).
Excavators are used to remove soft carious dentin and shape cavity walls. Types include spoon, discoid, and cleoid excavators.
Chisels are used to plan and cleave enamel, remove undermined enamel, or cut dentin away. Types include straight chisels, mono-angle chisels, bin-angle chisels, and Wedel-stadt chisels.
Dental Cutting Burs: Classified by material (Tungsten carbide, Steel) and shape (rounded, inverted cone, fissure).
Cutting efficiency depends on bur material (Tungsten carbide is more efficient), bur design (number of blades, rake angle, clearance angle), tissue type (enamel, dentin), pressure, and speed.
Eccentricity/run-out of a bur refers to its maximum displacement from the central axis, causing vibration, decreased efficiency, increased heat, and reduced bur life.
Heat generation during cutting is influenced by friction between bur and tooth, pressure, speed, cutting area, cutting efficiency, and cutting time, affecting the pulp.
Coolants are necessary to control heat generation, improve visibility, prevent clogging, and prevent pain.

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Description

This quiz covers various instruments and instrumentation essential for year 2 dentistry students. It classifies instruments by function, including isolation, exploration, removal, and restoration manipulation, providing a comprehensive understanding of their applications in dental practice.