Lecture 1 Flashcards
1
Q
The science and art in dentistry that studies the prevention, diagnosis, and treatment of defects in enamel and dentin
A
operative dentistry
2
Q
very brittle; cracks and breaks easily
A
enamel
3
Q
deforms a little before breaking; is ductile
A
dentin
4
Q
two types of operative dentistry
A
carious and non carious
5
Q
carious deals with ____ infection; diseased tissue has to be removed with precise ____ preparation
A
bacterial; cavity
6
Q
non carious deals with loss of surface tooth structure due to ____ or ____ factors
A
mechanical; chemical
7
Q
examples of non carious
A
attrition, abrasion, erosion, abfraction
8
Q
the goal of a restorative dentist is to remove the diseased tissue in a precise manner (_____) and replace the missing part with a restorative material (_____)
A
cavity preparation; restoration
9
Q
bacterial infectious disease that attacks tooth structure
A
dental caries
10
Q
mechanical alteration to remove the diseased tooth structure
A
cavity preparation
11
Q
Dental material used to restore back function and morphology of the missing part of the tooth structure
A
restoration
12
Q
Dental material placed in a soft state directly in cavity preparation to restore contour before it sets hard (amalgam and composite)
A
direct restoration
13
Q
A restoration fabricated outside the oral cavity then cemented or bonded to the tooth (inlay, onlay, crown)
A
indirect restoration
14
Q
a device that holds and delivers power to rotating instruments to perform tooth preparation
A
dental handpiece
15
Q
For many years has been the mainstay for cutting teeth
A
air driven dental handpiece
16
Q
Increasingly popular, quieter, cuts with higher torque, higher power and less stalling…more smooth cutting
A
electric dental handpiece
17
Q
runs at less than 12,000 rpm; no water coolants; less efficient, more controlled removal
A
slow speed handpiece
18
Q
uses for the slow speed handpiece
A
Controlled removal-deep caries excavation in close proximity to the pulp
Cleaning external surface of teeth (coronal polishing)
Finishing and polishing procedures (whether it is restoration or a preparation)
19
Q
12,000-20,000 rpm ; not used
A
medium speed handpiece
20
Q
> 200,000 rpm; generates considerable amount of heat and needs water coolant; most cutting efficiency (less vibration and pressure leading to less patient discomfort)
A
high speed handpiece
21
Q
uses for high speed handpiece
A
teeth preparation and removal of old restorations
22
Q
the ____ is the most common delivery tubing system in the dental unit control panel
A
4 hole connector line
23
Q
4 parts to the high speed hand piece
A
head (not detachable), attachment (contrangled), shaft, coupler
24
Q
the high speed hand piece head: push button, friction grip head holds only ____ type rotary instruments
A
friction grip burs
25
attaches the handpiece to the delivery unit and supplies air and water to the handpiece
coupler
26
the ____ receives the handpiece coupler
4 hole line
27
couplers can be ___ or ____ with ___ swivel
fixed; movable; 360
28
slow speed attachments
slow speed motor, nose cone/straight attachment, contra-angled attachment
29
the straight attachment is used for ____ procedures
extra oral (outside of the mouth); possibly polishing a crown from the lab
30
the straight handpiece uses a long ___ type bur or ___ bur
shank; straight
31
the contrangled slow speed head includes the ___ and _____
latch type (RA) head; friction grip head
32
the latch type (RA) head accepts only ____ burs
latch end
33
latch end burs are larger in ____ than the ____ burs
diameter; friction grip
34
the friction grip head uses friction grip type burs which have a smaller ___ and shorter ____ than the latch type burs
diameter; shanks
35
2 mechanisms of the friction grip heads
1. friction generated from an internal spring assembly (push button)
2. A special tool using force to overcome and generate friction (bur tool type)
36
3 components to rotary instruments
head, neck, shank
37
the working part of the rotary instrument; consist of either blades or abrasive particulate surfaces; many shapes and sizes
head
38
3 types of rotary instruments
bladed instruments, diamond (abrasive) instruments, other abrasives
39
3 types of shanks
straight/long shank, latch design (slow speed contrangled latch type), friction grip design (slow speed contrangle friction grip head and high speed)
40
not too bulky to interfere with operator's visibility, not too narrow to become a weak link between the head and shank
neck
41
bladed rotary instruments or burs are used for ____ and ____
excavating (cutting); finishing
42
excavating or cutting burs have ___ blades while finishing burs have ____ blades
6-8; 10-20
43
the greater the number of blades, the ___ the finish
smoother
44
how finishing burs are color coded
10-12 blades = red
16-20 = yellow
30 = white
45
bladed instruments can be composed of ___ for blade cutting and ____ for abrasive cutting
carbide; diamond
46
______ blanks ground to the desired shape. Stronger and harder than stainless steel but brittle
tungsten carbide
47
Tungsten carbide head is attached to the ____ neck and shank by ____ and ____
steel; welding; brazing
48
tungsten carbide blades used for ____
intracoronal preparations
49
diamond instruments: composed of a ____ blank on which small diamond particles are held together within a ____ matrix
metal; softer
50
on diamond instruments, the shank is color coded for degree of abrasiveness
yellow: superfine
red: fine
blue: medium
green: coarse
black: super coarse
51
diamond abrasives are used for _____
extracoronal preparations, like crown preps
52
* Abrasives placed on paper flexible backing to form discs or finishing strips • Discs attach to handpieces via mandrels
* Uses: finishing restorations
coated abrasives
53
* Molding abrasives and matrix into certain shapes
* Mounted (eg points and stones) vs Unmounted (cutting discs and stonewheels)
* Rigid (grinding and shaping) or Flexible (finishing and polishing)
molded abrasives
54
bladed head designs
round, inverted cone, pear shaped, plain cylindrical fissure, plain tapered fissure
55
apex (proximal part of bur) more narrow than base; flat ended bur, usually 1 mm in length
inverted cone bur
56
the diameter at the distal end of the pear-shaped bur is ____
0.8 mm
57
the 330 pear shaped bur is ____ in length with an __ degree taper and the 245 pear shaped bur is ___ in length with a ___ taper
1.5 mm; 8; 3.0 mm; 4 degree
58
the plain cylindrical fissure or 57 bur has ___ walls, no ___ and a diameter of ____
parallel; taper; 1 mm
59
the plain tapered fissure bur (also called ___) has a narrower ____ and wider ____; creates _____
171 long; base; apex; diverging walls
60
variability in head designs: end cutting
designate a 900 (end only carries the cutting blades)
61
variability in head designs: cross cut
designate a 500 before the bur number; also 700 version
62
mechanism of cutting
1. brittle fracture
2. ductile fracture
3. teeth undergo both
63
brittle material fractures by _____ upon tensile loading
crack formation
64
more efficient with brittle materials (microcracks)
abrasive cutting
65
plastic deformation of the material by shearing
ductile fracture
66
_____ more efficient with ductile material (deform then shear)
bladed cutting
67
____ materials are ductile
gold
68
____ burs are used for abrasive cutting, which is more efficient with brittle materials (microcracks)
diamond
69
abrasive cutting is not efficient with ____ material
ductile
70
cut by shearing layers of tooth structure
bladed cutting
71
bladed cutting is recommended for ______
intracoronal preparations
72
blade designs for bladed cutting
1. rake face
| 2. clearance face
73
the rake face...
the surface that forms the chip
| the surface of the blade towards the direction of cutting
74
the clearance face...
the surface that clears the chips
| away from the direction of cutting
75
direction of cutting is _____
clockwise
76
blade design angles
edge angle, rake angle, clearance angle
77
the edge angle is....
between the rake and clearance surfaces
78
the rake angle is...
between the radial line and the rake face
79
the clearance angle is....
the angle that provides clearance between the cutting edge and the tooth structure
80
when the radius (from cutting edge to axis of bur) is ahead of the rake face
positive rake angle
81
characteristics of a positive rake angle
- higher cutting efficiency
- larger chips produced
- chip space smaller; clogging of chip space
- always a chance to curve, fracture if material is not adequate
82
when the rake face is ahead of the radius (from cutting edge to axis of bur)
negative rake angle
83
characteristics of a negative rake angle
- decreased cutting efficiency
- smaller chips are produced; no clogging of the chip space
- cutting edge is spared (less liable to fracture) since carbide burs are brittle
84
____ are longer lasting
negative rake angles
85
purpose of the clearance angle
-prevents blade from rubbing on the tooth surface
86
the bigger the clearance angle...
the less the friction, dulling minimized, bur life lengthened
87
the ____ the clearance angle, the lower the longevity of the bur
smaller
88
basic components of hand instruments
handle, shank, and working end
89
connects the handle to the working end; can be straight or angled, rigid or flexible
shank
90
the working end is...
nib/point (non cutting instruments)
| blade (cutting instruments)
91
hand instruments are ____ if there are working ends on both ends
double ended
92
4 types of hand instruments
- examination instruments (non cutting)
- hand cutting instruments
- restorative instruments (non cutting)
- accessory instruments
93
examination instruments examine the ____, ____, and _____
teeth, soft tissue, and hard tissue
94
examples of examination instruments
mirror, explorer, periodontal probe
95
hand cutting instruments....
refine the walls of the tooth preparation to receive the restoration
96
restorative instruments...
insert dental material in the cavity preparation and carve back the tooth contour
97
accessory instruments...
aid to complete the procedure
98
has pointed tip to enhance tactile sensation for caries detection; also checks margins of crowns
explorer
99
examples of explorers
shepherd's hook (#23)
pigtail/cowhorn (#2)
interproximal explorer (#17)
100
measures cavity depth
periodontal probe
101
uses of hand cutting instruments
refine and shape the cavity walls
102
blade composition of hand cutting instruments
carbon steel (carbon harder than stainless steel)
103
handle composition of hand cutting instruments
stainless steel (the chromium in the stainless steel is corrosion resistant and retains the shine)
104
each hand cutting instrument is composed of 3 parts
handle, shank, and blade
105
the handle carries 2 codes:
1. instrument formula (ID formula)
| 2. manufacturer's serial number
106
the blade is the working part of the instrument that is _____ to create the cutting edge
beveled
107
concentration of the force onto the blade without rotation of the instrument
balance
108
basic instrument formula that consists of 3 units
black's instrument formula
109
1st number in formula
the width of the blade in tenth of a mm (10 mm = 1)
110
2nd number
the length of the blade in mm
111
3rd number
angulation of the blade to the long axis of the handle; expressed in 100th of a circle; always
112
four number formula
the 2nd number indicates the primary cutting edge relative to the long axis of the handle; always greater than 50
113
order of the 4 number formula
1. width of blade (in tenth of a mm)
2. primary cutting edge angle (> 50)
3. blade length in mm
4. blade angle relative to long axis in centigrade
114
restorative instruments...
insert and carve the restorative material
115
examples of restorative instruments
carrier, condenser/plugger, anatomical/acorn burnisher
116
examples of accessory instruments
articulating paper holder (miller forceps), scissors
117
example of accessory equipment
amalgam well
118
in direct cutting, the force applied is _____ to the cutting edge
perpendicular
119
how to do direct cutting
- hold instrument parallel to the wall being planed at all times
- the cutting edge in contact with the wall being planed
120
example of direct cutting instrument
enamel hatchet
121
force exerted is parallel to the cutting edge
indirect cutting/lateral cutting/scrapping
122
motion of lateral cutting
from the beveled to the non beveled side, i.e. away from the bevel
123
example of lateral cutting instrument
enamel hatchet and gingival margin trimmer
124
chisel family
1. straight/ slightly curved/ bin angled chisels (push motion)
2. enamel hatchet: direct cutting and lateral cutting
3. gingival margin trimmer: lateral cutting
125
enamel hatchet
- cutting edge parallel to the long axis of handle
- direct and lateral cutting
- double ended instrument with right and left bevels
126
gingival margin trimmer
- the blade is curved and not milled in a single plane: curved blade accentuates the lateral cutting
- cutting edge makes an angle to the long axis of the blade
- force is applied parallel to the cutting edge
127
excavator family
- ordinary hatchet
- hoes (pull)
- angle former
- spoon
