CHAPTER 6 - HIGH YIELD

What standard do all endodontic instruments follow?

ISO standards

Which hand-operated instrument is used for tissue removal?

Barbed broaches

Which hand-operated instrument has ISO-color coding and smallest tip size ISO 06?

K-type files

Which hand-operated instrument has fewer flutes and is used for reaming only?

K-type reamers

Which hand-operated instrument cuts on the pull stroke?

Hedstrom files

Which engine-driven instrument is used for tissue removal?

Lentulo spirals

Which engine-driven instrument is used for orifice opening?

Gates-Glidden drills

Which engine-driven instrument features parallel sides and a safe tip?

Peeso reamers

What motion defines filing in hand-operated instruments?

Pull and plane

What does the filing motion remove dentin on?

Pull stroke

What motion defines reaming in hand-operated instruments?

Twist and cut

What does the reaming motion remove dentin on?

Rotation

Which hand-operated instrument works well in both filing and reaming motions?

K-files

Which hand-operated instrument should not be filed?

Reamers

What is the weak point of a barbed broach?

Don't bind or force around curves

Which stainless steel file type is the strongest and least aggressive?

K-type files

Which file type has the sharpest cutting and cuts only on withdrawal stroke?

Hedstrom files

What is the shape of Gates-Glidden drills?

Flame-shaped

Why is the Gates-Glidden drill shaped to break high on the shank?

Easy retrieval

Which instrument features parallel, long cutting sides used only for initial flaring?

Peeso reamers

What is the cross-section shape of endodontic files?

Square

What is the cross-section shape of endodontic reamers?

Triangular

Which instrument has a greater area of cross-section, files or reamers?

Files

Which instrument has more flutes per millimeter, files or reamers?

Files

Which instrument has greater flexibility, files or reamers?

Reamers

What is the preparation shape created by files?

Ovoid

What is the preparation shape created by reamers?

Round

Which instrument provides better debris transport due to space present in flutes?

Reamers

What is the function of Lentulo spirals?

Spin pastes/sealers into canal at slow speed

What is the modulus of elasticity of NiTi compared to stainless steel?

1/4 to 1/5

What property of NiTi allows safe rotary use?

Cyclic fatigue resistance

Where do highest flexural stresses occur in curved canals?

Apical third (1-3 mm from tip)

Where do torsional fractures often start under torsion binding?

Apical third

What is a sign of file fatigue when observed in the apical 3 mm of a NiTi file?

Unwinding or plastic deformation of flutes

What mechanism of file fracture occurs when the tip binds while the shank continues to rotate?

Torsional overload

What mechanism of file fracture occurs from alternating tensile/compressive stresses in curved canals?

Cyclic fatigue

What motion is used in continuous-rotation NiTi systems?

360° unidirectional rotation

What motion is used in reciprocating NiTi systems?

Alternating CW/CCW angles

Which file system movement reduces net torsion through periodic reversal?

Reciprocating motion

What speed and torque are typically used for continuous-rotation NiTi?

~300 rpm; 1.5–2.5 Ncm

What is the recommended technique for continuous-rotation NiTi systems?

Crown-down technique

What file system is exemplified by WaveOne Gold and Reciproc?

Reciprocating NiTi

What device automatically stops or reverses at preset torque to prevent torsional overload?

Torque-controlled motor

What hand-file size is used to establish a glide path before rotary use?

ISO 15-20

What technique enlarges coronal, middle, then apical thirds sequentially to minimize binding?

Crown-down technique

What substance is used to reduce friction and torsional load during canal preparation?

EDTA or lubricating gels

What is the definition of disinfection?

Reduces microbial load (not necessarily sterile)

What is the definition of sterilization?

Complete elimination of all microbes, spores, viruses

What is the standard steam autoclave setting for instrument sterilization?

121 °C, 15 psi, 20 min

Which sterilization method is best for sharp instruments like scissors?

Dry heat

What chemical is commonly used for cold sterilization via immersion?

2% glutaraldehyde

What is a major limitation of cold sterilization (≥ 24 h immersion)?

Least verifiable (no biological indicators)