Midterm Flashcards
1
Q
Four number instrument formula is for -
A
margin trimmers
2
Q
What does each number mean of the four number instrument formula
A
15 = 1.5 mm width
98 = angle of edge to long axis of handle
10 = 10 mm blade length
14 = angle of blade to long axis
3
Q
Composition of hand instruments
A
Stainless steel:
Resists corrosion
Dulls easily (need to keep instruments sharp)
Carbon steel:
Corrodes
Holds sharpness
4
Q
most common excavator used
A
Spoon excavator
5
Q
Hand cutting instruments
A
Includes: chisels, hatchets, hoes, gingival margin trimmers, excavators, carvers
6
Q
Straight or curved
1, 2, or 3 angles
A
Chisels
7
Q
Cutting edge = in plane parallel with handle
1 or more angles
Do not use with too much force or twist (can easily break)
A
Hatchets
8
Q
Cutting edge is ⟂ to handle
A
Hoes
9
Q
Similar to hatchet, but has curved blades
Cutting edge is at angle to length of blade
A
Gingival margin trimmer
10
Q
Remove caries
A
Excavators
11
Q
Place anatomy
A
Carvers (Hollenback, cleoid, discoid)
12
Q
Used to place, condense, and carve restorative materials back to normal anatomy of teeth
Primarily made of stainless steel
A
Restorative instruments
13
Q
Restorative instruments
A
Includes: amalgam carrier, condensers, burnishers, carvers, amalgam knife, composite placement instruments
14
Q
Can be used to carry pliable restorative material to prepped cavity, although typically placed directly by composite gun
Used to shape material
A
Plastic instruments
15
Q
Shaft/handle can be
A
Small, medium, large
Smooth or serrated
16
Q
Shank
A
Connects handle to blade
Straight or angled
(Angled for access and stability)
17
Q
Blade
A
Working part of the instrument
Beveled to create cutting edge-Can have 3 bevels
Primary cutting edge on end
Secondary cutting edge on sides
18
Q
Ends to Hand instruments
A
double ended, or long handle with one working end
(Some probes, explorers, and mirrors have a single working end)
19
Q
3 categories of sterilization types:
A
critical, semi-critical, non-critical
20
Q
Critical =
A
penetrates soft tissue or bone
(Example: forceps)
Autoclave (most commonly used heat sterilizer in dentistry)
21
Q
Semi-critical =
A
do not penetrate, but contacts mucous membranes or non-intact skin
(Example: mirrors)
Autoclave or use high level EPA sterilant/disinfectant
22
Q
Non-critical =
A
comes in contact only with intact skin
Example: blood pressure cuff
Intermediate or low level disinfectant
23
Q
Class I caries =
A
most prevalent
Caries affecting pits and fissures on:
Occlusal ⅓ of molars and premolars
Occlusal ⅔ of B & L surfaces of molars and premolars
L surface of upper anterior teeth
Any other unusually located pit or fissure
24
Q
Pit/fissure lesions are more constricted at enamel surface and wider toward DEJ
A
Class I caries
25
Class II caries:
Caries affecting proximal surfaces:
Molars and premolars
26
Smooth surface interproximal lesions are generally wider at enamel surface
Class II caries
27
Class III caries
Caries affecting proximal surfaces of:
Central and lateral incisors
Cuspids without involving incisal angles
28
Class IV caries
Caries affecting proximal surfaces including incisal angles of anterior teeth
29
Class V caries
Caries affecting gingival ⅓ of facial or lingual surfaces of:
Anterior teeth
Posterior teeth
30
Class VI caries =
least prevalent
Caries affecting cusp tips of:
Molars
Premolars
Cuspids
31
Tooth surface loss from frictional forces
Abrasion
32
Tooth surface loss from chemico-mechanical action
Erosion
33
Mechanical wear from opposition teeth (grinding)
Attrition
34
Cervical, wedge-shaped defects as result of strong eccentric occlusal forces
Abfraction
35
Can be most difficult and challenging defects in teeth to diagnose and treat
Can be considered incomplete or complete; involving pulp or not involving pulp
Fracture
36
Loss of mineral from tooth structure, resulting from a chemical process (can be from caries, acid, diet, or gastric)
Demineralization
37
Breakdown of surface integrity that can be detected using optical or tactile methods
Cavitation
38
Can be confined to enamel or extend into dentin via tubular invasion
Can include differing layers of infected and affected dentin
Caries penetrate in a narrow or cone shaped channel to DEJ then spread laterally
Cavitation
39
Irreversible, demineralized, and denatured layer with bacterial invasion
Very soft, moist, and easy to remove with spoon excavator
Infected dentin
40
Partially demineralized
leathery/softer than normal
Collagen is not denatured
Contains minimal to no bacteria
Affected dentin
41
Outline =
external shape of prep
42
Visualize extent of caries
Allows bur to reach all carious dentin
Creates space for instrumentation and vision
Access to lesion
43
Extend outline to include all unsupported enamel
Enamel rods must be supported by sound dentin!
Extent of lesion
44
Carious dentin can have sound overlying dentin
Undermined enamel is usually removed
Lateral spread of caries at DEJ
45
Extent of caries in dentin determines
preparation size
46
Brittle materials require
90° cavosurface margin (amalgam or porcelain)
47
Ductile materials require
beveling of margin (composite or gold)
48
Do not leave -- on margin of restoration EVER
occlusal contact
(Thereshould not be a contact mark on the margin if the margin is enamel)
49
= shape that allows access (allows needed procedure to be performed) (Influences outline form also)
Convenience form
50
= shape given to prep to prevent fracture of either the restoration or tooth
Examples: adequate bulk of amalgam, rounding of internal line angles, horizontal pulpal and gingival floors prepared ⟂ to tooth’s long axis
Resistance form
51
Margins, 90 degrees to tooth -
Pulpal floor 1.5-2.0 mm -
Rounded internal angle -
- resists fracture at cavosurface margin
- helps resist restoration fracture
- resists internal stress
52
Prep is placed -- into dentin (not including enamel) for 3 reasons:
0.5mm
Avoid sensitive DEJ
Provide adequate bulk of restorative material
Take advantage of dentin’s resilience
53
= shape that prevents restoration from being displaced by tipping or lifting forces
Retention form
(Includes undercuts, truncation, grooves, pits, dovetails, etc)
54
Primary retention
Comes from
converging walls (sometimes dovetail)
55
Secondary retention
Helps retain restoration in case primary retention fails
Includes:
grooves, coves, extensions, skirts, beveled margins, pins, slots, steps, amalgam pins, etchants, adhesives (sometimes dovetail)
56
Note: must ALWAYS have --; -- is needed when indicated
primary retention
secondary retention
57
In many respects, -- and - are accomplished at the same time
retention form
resistance form
58
= touches uncut surface/cavosurface margin
External wall
59
= does NOT touch uncut surface/cavosurface margin
Internal wall
60
= rotary cutting instrument with bladed cutting head
Bur
61
Bur: Most have carbide head to steel neck
Carbide =
Steel =
-stiffer and stronger than steel; holds up better at high speeds, less prone to dull
- allows for decreased cost of fabrication and freedom in design
62
What has an Arbitrary 2 part numeral code indicating size and shape
Bur
63
What type of bur
Initial entry into tooth
Expansion of prep
Retention features
Caries removal
Round
64
What type of bur
Rapidly tapered cone with apex of cone directed toward shank
Head length = head diameter
Undercuts in tooth prep
Inverted cone
65
What type of bur
Slightly tapered cone with small end of cone directed toward shank
245 = elongated bur for amalgam preps
330 = small version of 245
Pear
66
What type of bur
Elongated cylinder
Straight fissure
67
What type of bur
Slightly tapered cone with small end of cone directed away from shank
Used for indirect restorations
Tapered fissure
68
Parts of bur
Fits into handpiece
Accepts rotary mutation from handpiece
Provides bearing surface to control alignment and concentricity of instrument
Shank
69
5 classes of shanks, but 3 are important to us:
Straight
Right angle latch
friction grip
70
Class of shank
Rarely used for prepping teeth
Used for oral surgery
Used for polishing indirect restorations
Straight
71
Class of shank
Used in slow speed handpieces
Fits into D-shaped socket at bottom of bur tube instead of a chuck
Right angle latch
72
Class of shank
Used in high speed handpieces
Small size allows for improved access with molars
Held in place using friction between shank and chuck within handpiece
Friction-grip
73
Part of bur
Intermediate portion that connects head to shank
Tapers from shank diameter to smaller size adjacent to head
Function = transmits rotational and translational forces
Smaller toward head to improve access and visibility
Neck
74
Part of bur
Working part of instrument
Cutting edges or points that perform desired shaping of tooth structure
Greatest area of variability based on intended application and technique
Head
75
Primary retention feature for amalgam =
Secondary retention feature for amalgam =
converging B and L walls
retention grooves and dovetails
76
Class I prep design
Class I =
pit and fissure prep
77
Dovetails = retentive feature
Considered primary if--
Considered secondary if -
part of inclusion of B/L grooves
not part of initial prep design, but as part of extension feature
78
Class I prep design
Width = -- of intercuspal distance
Minimizes tooth structure loss
Facilitates carving for amalgam restorations
Minimizes occlusal interferences
⅕ to ¼ (1.0 mm)
79
Class I prep design
Centered on central groove (--)
B to L width = no more than 1.0 - 1.5 mm (--)
Marginal ridges = 1.5 mm (--)
Pulpal floor is flat and ⟂ to long axis of tooth (--)
outline form
outline form
outline form
resistance form
80
Pulpal floor is flat and ⟂ to long axis of tooth (resistance form)
At right angle to direction of occlusal forces
Helps resist--
fracturing/shearing forces
81
Narrow anatomic part/passage connecting 2 larger structures
Created by preparing occlusal width/outline
Faciolingual extension
Contributes to retention and resistance form
Isthmus
82
Class I prep
Pulpal floor is deep enough to allow at least --of restorative material (resistance form)
1.5mm
83
Class I prep
Placed just into dentin to avoid sensitivity at --
Need minimum of --to prevent fracturing of restoration
Lesions shallower than 1.5 mm are generally -- (cavitation vs no cavitation)
Lesions extending 1.5mm indicates it has reached --
Need at least 1.5mm of restorative material, or it may not resist occlusal force (may fracture!)
DEJ
1.5mm
enamel-only lesions
DEJ
84
Class I prep
All cavosurface angles should be at a
right angle (90°)
85
Class I prep
All line and point angles should be -- to avoid stress concentrations (resistance form)
rounded, but defined,
86
Class I Prep
B and L walls -- (retention form)
Creates acute angle with pulpal floor
Provides primary retention
CONVERGE pulpo-occlusally
(Approximately 6° convergence)
87
Class I prep
M and D walls --(resistance form)
Creates obtuse angle with pulpal floor
Prevents undermining of marginal ridge
DIVERGE pulpo-occlusally
88
Once you start carving, you -- add to amalgam
CANNOT
89
Instruments used for amalgam occlusal anatomy
Steps
Condenser
Egg burnisher
Acorn burnisher
Cleoid/discoid
Refine with acorn burnisher
90
3 P’s of prevention
Postural awareness
Positioning strategies (dentist, patient and light)
Periodic stretching and exercise
91
-- are soft-tissue injuries caused by sudden or sustained exposure to repetitive motion, force, vibration, and awkward positions
These disorders can affect the muscles, nerves, tendons, joints and cartilage in your upper and lower limbs, neck and lower back
Musculoskeletal disorders (MSDs)
92
Pro/Con
Lathe-cut
Irregular in shape so higher packing forces needed during condensation
Minimal material related post op sensitivity
93
Pro/Con
Spherical alloy
Lower condensation pressure require to achieve same strength
Shorter working time, fast set, and high early strength
Greater risk of post op sensitivity
94
Advantage: you could work on the tooth the same day after restoring it with this type of amalgam
spherical alloy
95
Pro/con
Admixed (lathe-cut + spherical alloy all together)
This is the type of amalgam we have!
Combine best of both geometries
High Packing pressure with small condensers still required
Positive interproximal contact obtained
Slightly faster setting
Low post op sensitivity
96
Overall disadvantages of alloy
Not esthetic
Low tensile strength in thin sections under masticatory forces
It does not bond to tooth structure
Utilizes mercury
97
= metallic restorative material composed of a mixture of silver-tin alloy and mercury
Dental amalgam
98
Mercury in amalgam, and if it creates medical issue for patients
FDA says “Removing intact amalgam fillings results in unnecessary loss of healthy tooth structure and a temporary increase in exposure due to additional mercury vapor released during the removal process”
Subject of intense research and been found to be safe and beneficial as a direct restorative material
99
Benefits of amalgam as a restorative material
Successful as long lasting restorative material
More resistant to recurrent caries as compared to bonded composite resin restorations
Ideal for large restorations and when subsequent addressing of pulpal health is needed before a definitive restoration
Used as a foundation/core for badly broken down teeth that need extra retention and resistance forms in anticipation of crown placement
High mechanical properties - compressive strength, rigidity, and wear resistance
Packable insertion to provide positive proximal contact and intimate cavity adaptation
Carvable with hand instruments after insertion to provide optimal contour, surface, and occlusion
Self sealing properties over time
100
Purpose of -- to preserve the cusp and and triangular ridge and also facilitates the formation of a 90 degree cavosurface margin that creates a place of limited undermined enamel
reverse S curve
101
Where are class II carious lesions found in relation to contact point?
Class II caries are located just apical to contact point
102
Purpose and functions of matrix bands
For class II, matrix band replaces the missing proximal wall
103
-- slightly separates teeth to compensate for thickness of matrix band
Protects gingival tissue/rubber dam during prep
Seals matrix against gingival floor to avoid overhang of amalgam
Wedge
104
Parts of Tofflemire matrix retainer: Use outer nut to --
Use inner nut to --
Matrix band is placed through one of the --
lock matrix into retainer
adjust size of matrix
slotted guides
105
Tofflemire matrix retainer should
parallel the arch
106
-- = achieves smooth surface (pre-polish)
-- = creates lustrous polish
-- = creates high polish
Brownie polisher
Greenie polisher
Supergreenie polisher
107
-- = process of removing surface defects/scratches created during contouring process through use of cutting or grinding instruments (or both)
-- = most refined of the finishing processes; removes finest surface particle
Finishing
Polishing
108
How to cause mercury to rise to surface of amalgam restoration
During polishing, heat is created
Heat brings mercury to the surface of the restoration, which results in a dull, cloudy surface, and a surface that is more susceptible to corrosion
109
How long should you wait before finishing and polishing amalgam restorations?
At least 24 hours after it has been placed and carved
110
What is required for the development of caries?
Primary modifying factors + secondary modifying factors + host + cariogenic biofilm + time + fermentable carbohydrates = caries
111
Bacteria responsible for caries formation
Streptococcus mutans
