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69 Cards in this Set
- Front
- Back
1. What is enamel made of?
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95% - 98% inorganic
**brittle w/ high elastic modulus and low tensile strength **requires base of dentin for support |
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2. How is amalgam?
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1. Brittle
**require bulk for strength (1.5-2.0 mm) 2. Requires 90 degree margins fro strength 3. Requires undercuts for retention |
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3. What is composite?
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Filler particle embedded in a matrix
**polymerization shrinkage Bonds to enamel and dentin using acid etch **cavosurface margins can be butt joint or beveled |
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4. What is the initial stage of cavity prep?
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1. Outline form and initial depth
2. Primary resistance form 3. Primary retention form 4. Convenience form |
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5. What is the final stage of cavity prep?
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1. Removal of remaining enamel pit/fissure and/or infected dentin and/or old restorative material
2. Pulp protection 3. Secondary resistance and retention form 4. Finishing the external walls 5. Final procedures: cleaning, inspecting, varnishing, conditioning |
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6. What is primary resistance form?
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Cavity features that prevent fracture of tooth and/or restorative material
1. Depth 2. Unsupported enamel 3. Residual decay 4. Sharp angles |
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7. What is primary retention form?
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Mechanical undercuts required for amalgam
Mechanical and micro-mechanical for composite (acid etch) |
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8. What is convenience form?
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Cavity features that provide for adequate observation, accessibility, and ease of operation
Cavity designs changes based on tooth location, patient compliance |
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9. What is secondary resistance and retention form?
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Mechanical
-grooves, slots, boxes, pins **grooves/locks length is in a longitudinal plane **slot located in dentin on transverse plane Cavity wall conditioning features -enamel and dentin conditioning (micro-mechanical retention using acid etch) |
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10. What occurs when finishing the external walls?
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Development of cavosurface design that produces the max effectiveness of the restorative material
Amalgam: butt joint margins Composite: butt joint or beveled Cast restorations: bevels |
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11. What is primary caries?
What are the morphological types of primary caries? |
Original carious lesion of the tooth (never been drilled on before)
1. Pit and fissure 2. Smooth surface 3. Root surface |
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12. What are pit and fissure caries?
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Areas of imperfect coalescence of the developmental enamel lobes on the occlusal of posterior teeth and maxillary incisors
Difficult to cleanse and therefore susceptible to decay if oral conditions are conducive |
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12. What are smooth surface caries?
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Caries in a smooth area of enamel that is habitually unclean and covered w/ plaque
Proximal surface of posterior teeth Ideally disrupt bacterial mass w/ daily flossing |
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13. What are root surface (senile) caries?
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Rapidly progressing caries on root surface
Root surface is softer and more difficult to keep clean **important anatomic features: CEJ DEJ (0.5 mm into dentin when doing prep) |
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14. What are residual caries?
What are secondary or recurrent caries? |
Caries that remains in a completed cavity preparation
**on pulpal floor or DEJ Caries occurring at the borders of a restoration and then progressing under it |
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15. What are incipient (reversible) caries?
What are white spot lesions? What are brown spot lesions? |
First evidence of caries activity in the enamel
**Hasn't reached DEJ (not into dentin) Only in enamel, opaque white when dry, normal when wet Remineralized white spot lesion (restoration not indicated) |
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16. What are cavitated (non-reversible) caries?
What are acute or rampant caries? What are chronic (slow or arrested) caries? |
Decay advanced into dentin
**Enamel is no longer intact and remineralization is not possible Rapid in progression Alternating periods of demineralization and remineralization **lesions could be dark in color w/ sclerotic dentin present |
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17. What is enameloplasty?
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Grinding away a shallow enamel developmental fissure/pit to create a smooth saucer-shaped surface which is self or easily cleaned
Can also be used to enhance proper finishing of a restoration whose margins cross it Can be used to remove caries prone geometry w/o over-extending outline **not more than 1/3 enamel thickness should be removed |
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18. What is infected dentin (outer zone of dentin decay)?
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Zone of dentin decay where bacteria is present
**collagen is irreversibly denatured, cannot remineralize, and must be removed |
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19. What is affected (inner) dentin?
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Collagen is reversibly denatured, not infected and remineralization is possible
This dentin should be preserved and can be differentiated clinically by... 1. Degree of discoloration 2. Degree of hardness as evaluated w/ an explorer or excavator |
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21. What are different types of abnormal tooth surface loss?
four types... |
1. Abrasion
-tooth to foreign object w/ or w/o an abrasive present **gingival 1/3 2. Erosion -chemical mechanical action 3. Attrition -toot to tooth contact (parafunctional habits) 4. Idiopathic erosion -cervical wedge shaped defects resulting from microfractures due to heavy eccentric occlusion (parafunction habit - grinding) |
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22. How is the strongest enamel margin?
What is a line angle? What is an internal line angle? What is an external line angle? What is a point angle? |
Buttressed by progressively shorter rods whose inner ends rest on sound dentin
Junction of 2 planal surface of different orientation along a line Lina angle whose apex points into the tooth Line angle whose apex points away from the tooth Junction of three line angles |
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23. What is the cavosurface angle?
What should it be? |
Angle formed by the junction of a preparaed cavity wall and the external tooth surface
Should be bwt 80 - 100 degrees for amalgam |
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24. What are the classifications of cavities?
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Class I
-occlusal surface of molars / premolars -occlusal 2/3 of F. and L. of molars -L. surface of max incisors Class II -proximal surface of posterior teeth Class III -proximal surface of anterior teeth Class IV -proximal of anterior w/ incisal edge Class V -gingival 1/3 of F. and L. of all teeth Class VI -incisal edge of anterior teeth -cusp tips of posterior teeth |
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25. What is the length of the #330 bur?
What is the length of the #245 bur? |
330: 1.3 - 1.5 mm
245: 3.0 mm (width is 0.8 mm) |
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26. How is the outline form determined?
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1. Clinically by decay
2. Classical conservative class I lesion follows primary anatomy of pits and fissures **produce marginal outline form free of sharp angles |
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27. What should the isthmus width be?
What should the depth be? |
1. Width is not more that 1.5 times the width of the bur
2. Width is not more than 1/4 the inter-cuspal distance 1.5 - 2.0 mm (0.5 mm into dentin) |
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28. What is resistance form or cavosurface geometry?
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1. Isthmus width
2. Depth 3. Flat floors 4. Butt joints (90 degree cavosurface margins) 5. Rounded axio-pulpal line angles |
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29. What is retention form?
What is refinement and internal definition? |
Occlusally converging walls
1. Smooth walls 2. Well-defined line angles 3. Gingival wall width and contour |
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30. How should the handpiece be angulated?
Where should you be during operative procedures? Where should you be during oral examinations? |
Top of hand piece parallel to occlusal surface (or surface you are working on)
Work from behind the patient Work from behind or beside the patient |
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31. What is the criteria used to identify decay?
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1. Visual
-chalkiness radiating from occlusal fissures 2. Radiographic -decalcified tooth structure appears darker (less dense b/c demineralized so radiolucent and darker) 3. Tackiness/physical stick w/ explorer -aggressive probing can damage fragile enamel causing cavitation |
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32. How are the cones of decay in a pit and fissure decay?
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Cones of decay at DEJ are base to base
Example: class I lesions **decay spreads out at DEJ |
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33. How can you distinguish enamel from dentin?
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1. Color
-dentin is yellower and slightly darker 2. Reflectance -dentin is less reflective (opaque and dull) 3. Hardness 4. Sound -enamel produces higher pitched sound |
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34. What other colors can dentin be?
How are enamel rods oriented? How are accessory grooves in cavity prep outline form? |
Brown or black when it's been exposed to oral fluids, old restorative materials, or slowly advancing decay
Perpendicular to external surface of tooth Extend half-way bwt central fossa and cusp tip |
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35. When is it necessary to flare (diverge) the marginal ridges?
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If less than 1.5 mm from contact point make 10 degree flare into marginal ridges
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36. What are the rules of rubber dam application?
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1. Minimum of five teeth isolated
2. Never end on canine 3. Stable clamp, four pt contact (just prongs touch tooth) 4. Safety floss attached 5. Punch correct size/distance apart 6. Accommodate for crowding and missing teeth |
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37. When is an anterior clamp used?
What is W56 used for? W7? W8? W4? |
Retract the gingiva for class V lesion
**W means it's wingless W56: most molar anchor teeth W7: mand. molar anchor teeth W8: max molar anchor teeth W4: most premolar anchor teeth |
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38. What is a W2 used for?
W27? How is a W14 or 14a? |
W2: small premolar anchor teeth
W27: terminal mand. molar anchor teeth requiring preparations involving distal surface Prongs are pointed gingivally |
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39. What should you lubricate the dam with?
How should the dam be in relation to the sulcus? How is the dam removed? |
Lubricate w/ water based solvent (no vasoline)
Inverted into sulculs 1. Stretch and cut septa 2. Remove clamp and frame 3. Check for missing pieces |
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40. What is the distance between two holes on the rubber dam?
What happens if the distance is excessive? What happens if the distance is too little? |
Distance from center of one tooth to center of adjacent tooth measures at gingival 1/3
Wrinkles bwt teeth Stretching causes leakage |
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41. Where should the hole be punched for maxilla?
For mandibular? |
Punch central incisor hole first (1 inch from superior dam border)
First punch posterior anchor tooth receiving retainer 1st molar - halfway from superior edge to inferior at junction of right and middle thirds 2nd or 3rd molar - towards inferior border and center of dam 1st premolar - towards superior border and center of rubber dam |
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42. What is the purpose of the "s" curve?
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Preserve tooth structure around cusp and pulp horn
Also provides for proper proximal cavosurface angle |
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43. What are cutting and non-cutting handpieces?
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Cutting
-excavators -hatchets -hoes -chisels -angle formers -spoons Non-cutting -condensers -mirrors -explores -probes |
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44. What is the design of the instrument?
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1. Handle
2. Shank 3. Blade (or nib on non-cutting) |
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45. How can the handle be?
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1. Eight sided or knurled
**knurled so don't slip 2. Long handled or cone socket **cone socket allows you to but just mirror |
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46. How can the shank be?
What does bending of the shank do? |
Straight or bent
1. Optimizes balance (eliminate hand fatigue) 2. Brings cutting edge w/in 1-2 mm of the long axis of the handle |
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47. What are the components of the blade?
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1. Primary cutting edge
2. Secondary cutting edge **cutting edges can be beveled and bevel always faces away from the surface being cut |
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48. What is the identification formulas of operative instruments?
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First number - width of blade
(tenth of millimeter) Second number - angle of cutting edge from long axis of the shaft **always greater than 50 (if have four numbers) Third number - length of blade (mm) Fourth number - angle of the blade from the long axis of the shaft **always less than 50 (centigrades or hundreth of circle) |
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49. What does it mean if the identification formula only has three numbers?
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Cutting edge is 90 degrees
(leave out second number) |
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50. How can a chisel be designed?
How is the cutting edge of a chisel? How is it used? What is the difference between a regular bevel and reverse bevel? |
Straight, curved, or angled
Cutting edge is perpendicular to long axis of handle Regular - bevel faces away from operator Reverse - bevel faces the operator |
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51. How is a hoe designed?
How is it used? What is it used for? |
Single ended and regular bevel
Used in a pull motion Used to smooth floors and form line angles **esp in direct filling gold |
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52. How is the cutting edge in the hatchet?
How is the hatchet designed? How is it used? What is it used for? |
Cutting edge is parallel to long axis of the handle
Doubled ended w/ left or right side cutting edge (has primary and secondary cutting edges) Used in chopping motion Used on gingival, axial and lateral walls of proximal box (refinement) |
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53. What is bibeveled ordinary hatchet used for?
What is an angle former? What is it used for? |
Used for retentive areas and sharpening internal line angles
Combination chisel and gingival margin trimmer Used to place dentin retention features, bevels and sharpen line angles |
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54. How is the cutting edge in a gingival margin trimmer?
What is the design of the gingival margin trimmer? How can the mesial and distal pair be distinguished? |
Cutting edge at an angle to the long axis of the blade
(has angle so #4 instrument) 1. Modified hatchet 2. Double ended and left and right sided 3. Curved blade and angled cutting edge 4. Mesial and distal pair Distal - 2nd # is 90 - 100 Mesial - 2nd # is 75 - 85 |
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55. What do 100 and 75 gingival margin trimmers do?
What do 90 and 85 gingival margin trimmers do? In general what are gingival margin trimmers used for? |
Produce a steep angle for placing bevels on inlay and onlay preps
Angled for amalgam preps Used in proximal box to round axiopulpal line angle and remove unsupported enamel |
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56. What are some "miscellaneous" instruments?
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1. Knives
-trim excess "soft" interproximal material 2. Files -trim excess "set" interproximal material 3. Discoid-cleoid (carving) 4. Spoon excavators (caries removal) 5. Non-cutting instruments -explores, probes, mirrors |
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57. What is the design of rotary cutting instrument?
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1. Head
2. Neck 3. Shank |
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58. What are some characteristics of blades?
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1. Shorter blades are more efficient
2. Twisted to decrease vibration 3. Excavating burs have 6-10 blades (rough surface) 4. Finishing burs have 12-40 blades **less efficient at cutting but produce a smoother surface |
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59. What are flutes?
How are bigger flutes? What is the clearance angle? What is the rake angle? |
Space between blades
Bigger flutes are more efficient at debris removal and cleaning Angle the back of the blade makes w/ the tooth **smaller is better Angle the face of the blade makes w/ the radial line **positive is not acceptable |
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60. How are round burs numbered?
What are they used for? |
1/4 to 10
1. Initial entry (class III) 2. Extension for prevention 3. Enameloplasty 4. Retention features (1/4) 5. Caries removal |
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61. What are the numberings for inverted cone burs?
How are they designed? What are they used for? |
33 1/3 - 39
Rapidly tapered cone w/ apex of the cone directed toward the bur shank Length same as diameter Used for preparing undercuts in dentin |
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62. What are the numbers for straight fissure bur?
How are they designed? What are they used for? |
55 - 61
*greater # = greater diameter Elongated cylinder Flat or curved tip Large amalgam preps (4 mm) **when that large prep does not need undercuts |
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63. What are the numbers for tapers fissure bur?
How are they designed? What are they used for? |
169 - 173
Slightly tapered cone w/ small end of the cone directed away from the bur shank Won't create undercuts (top diameter is smallest) Used from crown preps (diverging walls) |
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64. What is flat or rounded tip bur used for?
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Preps requiring no undercuts (crowns, inlays/onlays)
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65. What are the numbers for pear shaped burs?
How are they designed? What are they used for? |
329 - 333 and 245
Slightly tapered inverted cone w/ small end of the cone directed toward the shank 1. Flat or curved end 2. Normal or long length normal - length is wider than width long - length is 3x width Used for amalgam preps b/c produced undercuts |
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66. What are some variations of the basic bur types?
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1. End cutting (956 - 960)
-used in deep proximal boxes -do not cut on side 2. Crosscut fissures (aggressive bur) -straight (555 - 561) -tapered (700 - 703) |
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67. What does a "L" denote?
What does a "1" or "11" on a tapered or straight fissure bur mean? |
"L" denotes longer cutting head
Denotes a round cutting end 1156 - round end plain fissure 1556 - round end cross cut fissure |
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68. What are the characteristics of diamond burs?
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1. Efficient at cutting brittle substances (i.e. enamel)
2. Long life if cleaned and used w/ water spray (prevent clogging) 3. Head, neck, shank 4. Metal blank layered w/ powered diamond 5. Many shapes possible (poor numbering system 6. Used for crown preps (remove almost all enamel) |
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69. What are some precautions when using cutting instruments?
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1. Pulpal protection
-use water spray to prevent disiccation of tooth 2. Soft tissue protection 3. Eye protection 4. Ear protection 5. Inhalation protections |