Instruments & Instrumentation - Operative Dentistry Year 2
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Questions and Answers

What is the purpose of rounding the axio-pulpal line angle in dental procedures?

  • To increase tooth sensitivity
  • To avoid stress concentration (correct)
  • To enhance aesthetic appearance
  • To reduce the risk of microleakage

    • Which grasp is most appropriate for delicate work and finishing enamel walls?

  • Power grip
  • Modified palm and thumb grasp
  • Pen grasp (correct)
  • Palm and thumb grasp

    • What is one significant advantage of using hand cutting instruments over rotary cutting instruments?

  • They require less skill to operate
  • They do not cut into sound tooth structure (correct)
  • They are faster in operation
  • They are less expensive

    • What is a characteristic of rotary cutting instruments?

    <p>They include both burs and abrasives</p> Signup and view all the answers

    When should the palm and thumb grasp be utilized in dental procedures?

    <p>On the palatal surface of anterior teeth</p> Signup and view all the answers

    What does the first number in Black's formula represent?

    <p>Width of the blade</p> Signup and view all the answers

    Which material of instruments offers better cutting efficiency?

    <p>Carbon Steel</p> Signup and view all the answers

    How are instruments classified according to beveling?

    <p>Single beveled, bi-beveled, triple beveled, and circumferential bevels</p> Signup and view all the answers

    What function do excavators serve?

    <p>Excavation of soft carious dentin</p> Signup and view all the answers

    In Black's formula, when is the fourth number added?

    <p>When the cutting edge is not perpendicular to the long axis</p> Signup and view all the answers

    Which classification pertains to instruments based on the number of ends?

    <p>Single-ended and double-ended</p> Signup and view all the answers

    What is the advantage of stainless steel instruments?

    <p>They are more corrosion resistant</p> Signup and view all the answers

    What is meant by 'contra-angling' in hand instruments?

    <p>Adding an angle for balance and accessibility</p> Signup and view all the answers

    What effect does increasing the number of blades on a bur have?

    <p>Increases cutting efficiency within limits.</p> Signup and view all the answers

    Which type of bur has the highest cutting efficiency?

    <p>Tungsten carbide bur</p> Signup and view all the answers

    What is the best rake angle for cutting efficiency?

    <p>Zero rake angle</p> Signup and view all the answers

    How does an increase in pressure affect the bur's performance?

    <p>Increases cutting efficiency but may lead to heat generation.</p> Signup and view all the answers

    Which tissue is harder and therefore affects cutting efficiency of the bur?

    <p>Enamel</p> Signup and view all the answers

    Why are inverted cone burs more efficient compared to fissure burs?

    <p>They cut only in dentin and have a smaller cutting area.</p> Signup and view all the answers

    What is the relationship between bur speed and cutting efficiency?

    <p>Increasing speed improves cutting efficiency.</p> Signup and view all the answers

    Which coolant type is considered the best for dental cutting?

    <p>Air-water sprays</p> Signup and view all the answers

    What happens if a positive rake angle is utilized excessively?

    <p>Increases the risk of blade fracture.</p> Signup and view all the answers

    What is one of the primary functions of coolant during dental procedures?

    <p>To clean the operating area</p> Signup and view all the answers

    Which statement accurately differentiates dental stones from dental burs?

    <p>Stones consist of abrasive particles, whereas burs consist of cutting blades.</p> Signup and view all the answers

    What is a primary consequence of using abrasive instruments on dentin?

    <p>Clogging of abrasives leading to pain</p> Signup and view all the answers

    What is a characteristic of carbide burs compared to abrasives?

    <p>They are more effective in cutting dentin.</p> Signup and view all the answers

    What is the maximum lateral displacement of the working point of an instrument as defined for run-out?

    <p>0.025 mm</p> Signup and view all the answers

    What should always be used along with dental abrasives during procedures?

    <p>Copious coolant</p> Signup and view all the answers

    Which of the following is NOT a cause of run-out?

    <p>Defect in the cutting material</p> Signup and view all the answers

    How does increased pressure affect friction during the cutting process?

    <p>Increases friction</p> Signup and view all the answers

    Which is NOT a function of coolant mentioned in the content?

    <p>Enhance the taste of dental materials</p> Signup and view all the answers

    Which effect does excessive heat generation have on dental pulp?

    <p>Irreversible pulpal inflammation</p> Signup and view all the answers

    Which statement correctly describes the use of amalgam carriers?

    <p>They are used for packing restorations.</p> Signup and view all the answers

    What is a recommended method to control heat generation during dental procedures?

    <p>Minimizing working time</p> Signup and view all the answers

    What is the potential consequence of pulp temperature exceeding 135°F?

    <p>Thermal pulp shock</p> Signup and view all the answers

    Which factor does NOT affect the amount of friction during dental cutting procedures?

    <p>Type of material being cut</p> Signup and view all the answers

    What is an effective way to decrease friction in dental tools?

    <p>Selecting sharp tools with high cutting efficiency</p> Signup and view all the answers

    What are the main advantages of air abrasion in cavity preparation?

    <p>Painless procedure</p> Signup and view all the answers

    Which of the following is a disadvantage of laser treatment in cavity preparation?

    <p>Generates significant heat that may affect the pulp</p> Signup and view all the answers

    What is a key characteristic of sonic instruments in dentistry?

    <p>Designed to avoid injury to adjacent teeth</p> Signup and view all the answers

    What is the primary purpose of Carisolv gel in dentistry?

    <p>To soften carious dentin before removal</p> Signup and view all the answers

    Which of the following represents a common misconception about rotary cutting instruments?

    <p>They generate excessive heat which always leads to pain</p> Signup and view all the answers

    What component of hand cutting instruments connects the shaft to the blade?

    <p>Shank</p> Signup and view all the answers

    Enzymes like Pronase are used in cavity preparation mainly to:

    <p>Dissolve carious dentin effectively</p> Signup and view all the answers

    Which part of a hand cutting instrument is primarily responsible for grasping during use?

    <p>Shaft or handle</p> Signup and view all the answers

    Study Notes

    Instruments & Instrumentation - Operative Dentistry, Year 2

    • General Classification of Operative Instruments: Instruments are categorized by their use, including isolation, exploration, tooth substance removal, restoration manipulation and finishing/polishing. Additional miscellaneous instruments complete the list.

    Isolation of Operative Field

    • Instruments maintain a dry operative field, including rubber dam placement, saliva ejectors, and high suction evacuation. Cotton roll holders also aid in this process.

    Exploring the Operative Field

    • Instruments used to assess the operative field, such as mouth mirrors and explorers (single-ended preferred). Magnifying loupes, microscopes, and intraoral cameras are also utilized.

    Removing Tooth Substance

    • Hand cutting instruments: Employed for precise cutting and shaping of tooth structure.
    • Powered cutting instruments:
      • Rotary cutting instruments: Burs and abrasive materials; used for creating cavities.
      • Air abrasion: Air stream combined with abrasive particles (Aluminum oxide) for tooth removal.
      • Laser (Waterlase): Absorbed by tooth and converted into heat, causing destruction and necrosis.
    • Sonic instruments: Cutting ends with abrasive particles on one side and no abrasive on the other, to avoid injury to adjacent teeth. These are safe-sided tools.

    Chemo-mechanical methods (Carisolv)

    • Gel-based treatment: Applied to exposed carious dentin.
    • Softens carious dentin which is removed after a set time using hand instruments, creating a caries-free cavity.

    Enzymes

    • Pronase: A non-specific enzyme that removes carious dentin.

    Hand Cutting Instruments

    • Definition: Tools used for cutting enamel and dentin for cavity preparation.
    • Parts of H.C.I: Composed of a shaft/handle, shank, and blade.
      • Shaft/Handle: Serrated or angulated for grip avoiding slippage.
      • Shank: Straight or contra-angled; connects shaft to the blade.
      • Blade: Performs cutting action and is specifically called 'NIB.'
      • Manufacturer's Name, Designer, Kit Number, Black's Formula, and Indicating Marks (R or L) are engraved on instruments and aid in identification.

    Black's Formula

    • System of figures describing instrument measurements. Includes width of blade (first number), length of blade (second number), angle of blade to the shaft (third number), angle of cutting edge to the shaft (fourth number, if necessary). Fourth number appears in place of second number if needed.

    Material of the Instruments

    • P.O.C: Low Corrosion resistance, easily sharpened but also brittle.
    • Carbon Steel: Excellent sharpness/cutting efficiency, but prone to corrosion.
    • Stainless Steel: High corrosion resistance, but not as sharp or durable as carbon steel.

    Types and Classification of Hand Cutting Instruments

    • Classified by use (excavator, chisel), direction of cutting (direct, lateral), beveling (single, bi, triple, circumferential), and number of ends (single, double).

    Excavators

    • Definition: Used to remove soft carious dentin and shape cavity walls.
    • Types: Straight, mono-angle, bin-angle, and triple-angled, spoon excavator.
    • Functions: Excavate and remove carious dentin and shape the cavity walls. Carving of amalgam is possible using certain types.

    Chisels

    • Definition: Used to plan and cleave enamel and dentin, planning the walls of a cavity.
    • Types: Straight, mono-angle, bin-angle, wedel and angel former (modified straight chisel).

    Dental Cutting Burs

    • Classification by material (e.g., tungsten carbide, steel) and by shape (e.g., rounded, inverted cone, fissure).
    • Factors such as number of blades (cutting, finishing), length of shank, and blade angles (tooth, clearance, rake) affect efficiency.

    Advantages of Hand over Rotary Instruments

    • Conservative cutting (doesn't damage healthy tooth structure)
    • No vibration or heat generation
    • High efficiency and time saving
    • Smoother, better finished surfaces
    • Long life span.

    Instrument Grasps, rests, and guards

    • Grasps (methods of holding an instrument): Pen, palm-and-thumb, modified palm-and-thumb
    • Rests: Fingers not holding on to support the instrument and avoid slippage.
    • Guards: Fingers of the opposing hand used to protect adjacent tissues.
    • Rotary cutting instruments: Burs used for cutting and abrasives for abrasion, along with specifics for electric and air operated hand pieces and shapes. The speed and type of motor influence use.

    Cutting Efficiency

    • Ability to remove maximum tooth structure with minimal effort and time.
    • Factors that influence efficiency include bur material (hardness, high melting point, design), bur design, tissue type (enamel vs. dentin), pressure, and speed.

    Eccentricity or Run-Out of Bur

    • Maximum displacement, in mm, of bur from central axis; defects in the bur, its attachment, the hand piece, the junction between the motor and the hand piece cause eccentricity.

    Heat Generation

    • Friction between bur and tooth surface, generating unwanted heat. Pressure, speed, area of cutting, cutting efficiency, and time of cutting influence friction and thus heat generation.
    • Dissipation of heat occurs through the tool, tooth, atmosphere, and formed dentin chips.
    • Excessive heat can damage pulp tissue, leading to dehydration of pulp, burning lesions, pulp hyperemia, irreversible pulpal inflammation and thermal pulp shock.

    Coolant

    • Biologically compatible, similar body temperature, sufficient amount, directed to area to be cut. Types include water, air spray, and air/water spray. Function is to control heat, lubricate, improve vision, clean the bur, decrease pain, and prevent clogging, increasing its lifespan.

    Dental Stones or Abrasives

    • Differences from burs are that they use abrasive particles instead of cutting blades, intended for abrasion instead of cutting and the need for a plentiful supply of coolant because of increased friction and resultant heat generation.
    • Abrasives are best used in extra-coronal situations, while carbide burs are most effective in intra-coronal situations.

    Instruments Used for Manipulation and Packing Restorations

    • Amalgam carrier: Instrument with hollow end for carrying amalgam increments.
    • Condensers: Hand instruments used for packing and condensing amalgam.
    • Plastic Instruments for Composite: Tools for handling, shaping, and manipulating composite materials.
    • Triturating and Mixing instruments: Tools for amalgam mixing.
    • Matrices: Used to shape and form cavities for restorations.
    • Light curing units: To polymerize resinous composite materials.

    Instruments for Shaping/Finishing/Polishing Restorations

    • Burnishers: Instruments used to burnish amalgam and cast gold restorations. Available in various sizes.
    • Carvers: Used to shape amalgam after packing and vary in shape for different aspects of the restoration.
    • Plastic instruments for composite: Used for handling, shaping, and/or manipulating composite restorative materials.
    • Hand finishing Instruments (e.g., orange wood sticks): Finishing strips used to finish composites.
    • Rotary Finishing Instruments: Including brushes, rubber wheels, cups, points, and various finishing burs, abrasive finishing discs, and finishing stones.

    Miscellaneous Instruments

    • Instruments that do not fall into the above categories, such as mouth mirrors, probes, and pliers.

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    Instruments & Instrumentation Year 2 PDF

    Description

    This quiz explores the classification and application of various instruments used in operative dentistry. It covers isolation techniques, exploration methods, and the removal of tooth substance using both hand and powered cutting instruments. Test your knowledge on the essential tools for maintaining a dry operative field and effective diagnosis.

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