Principles of Operative Dentistry Flashcards
1
Q
what is operative dentistry?
A
treatment of disease/defect of hard tissues of teeth that do not require full coverage restoration
2
Q
what does operative dentistry do?
A
restores form, function, and esthetics
3
Q
enamel thickness varies by (2)
A
location
tooth type
4
Q
enamel is –% hydroxyapatite
A
90-92
5
Q
enamel is (2)
A
strong and brittle
6
Q
enamel rod diameter
A
larger near surface, smaller near dentin borders
7
Q
how are enamel rods oriented?
A
perpendicular to long axis, radiate outward (like spokes on a wheel)
8
Q
do not leave — enamel
A
unsupported
9
Q
grooves and fissures can act as a
A
food/bacteria trap (leads to decay)
10
Q
Enamel Tufts (2)
A
◦Hypomineralized
◦Extend into enamel
11
Q
Enamel lamellae (2)
A
◦Thin faults between enamel rod groups
◦ Extend from enamel toward DEJ
12
Q
Enamel Spindles
A
◦Odontoblastic process crossed into enamel
13
Q
Dentino-Enamel Junction
A
◦Hypomineralized Zone where dentin meets enamel
14
Q
enamel solubility
A
more soluble as your approach DEJ
15
Q
how does fluoride impact acid solubility of enamel?
A
it lowers acid solubility, important to remember both when considering caries and when considering bonded restorations
16
Q
pulp-dentin complex (2)
A
stron and resilient
living tissue
17
Q
pulp-dentin complex (2)
A
stron and resilient
living tissue
18
Q
largest portion of the tooth
A
dentin
19
Q
dentin is located in both
A
coronal and root portions of tooth
20
Q
dentin forms the walls of
A
pulp chamber
21
Q
dentin is formed immediately — to enamel
A
prior
22
Q
dentin formation continues throughout the
A
life of the pulp
23
Q
dentinal tubules canals extend from
A
DEJ/CEJ to pulp
24
Q
dentinal tubules are lined with
A
peritubular dentin
25
--- is located between dentinal tubules
interdentin
26
diameter of dentinal tubules is largest at the
pulp
27
number of dentinal tubules/square mm is greatest at the
pulp
28
reparative dentin is formed by
secondary odontoblasts
29
reparative dentin is a response to
moderate irritant
30
sclerotic dentin (2)
primary dentin that has changed
| peritubular dentin widens and fills with calcified material
31
dentin hardness
averages 1/5 that of enamel
32
dentin is harder near
DEJ than pulp (3x)
33
dentin is --% hydroxyapatite
50
34
dentinal sensitivity
fluid movement in tubules
35
Hydrodynamic Theory of Pain Transmission
◦Odontoblastic process wrapped in nerves and fluid in dentinal tubules
◦Enamel/cementum removed during preparation= seal is lost
◦ Causing small fluid movements in tubules= distortions in nerve endings
◦ = PAIN
36
smear layer is created whenever
tooth is cut/prepared
37
smear layer plugs
dentinal tubules
38
enamel (4)
◦Gray, semi-translucent
◦Color depends on underlying dentin
◦Becomes temporarily whiter when dehydrated
◦Shiny
39
dentin color (2)
◦Yellow-white
| ◦Dull, opaque
40
cementum (3)
* Covers root surface
* Softer than dentin
* Formed continually
41
CONTOURS
Curve or shape of something
42
Overcontour vs overcontoured
Overcontour: flat
overcontoured: bulky
43
PROXIMAL CONTACT
Where two adjacent teeth contact (Vs occlusal contact)
44
EMBRASURES
an opening with sides flaring outward
In dentistry, V-shaped valleys between adjacent teeth
◦ Gingival usually fills in this space
45
SKIPPED
| Objectives of Tooth Preparation (6)
* Resistance Form, Retention Form, Convenience form
* Remove defects
* Provide necessary protection to pulp
* Extend restoration as conservatively as possible
* Resist fracture when chewing
* Restore esthetics and function
46
tooth prep should be precise, especially for
amalgam
47
GV black
prep design and principles
48
preparations for composite restorations incorporate
bonding
49
Preparation
Extend to sound tooth structure in all directions
50
Prep walls are designed to (2)
◦ RETAIN restoration
| ◦ RESIST fracture
51
Preparation (5)
* Remove remaining caries or old restorative material
* Protect pulp
* Minimize fracture, maximize retention
* Finish walls and margins
* Final cleaning, inspection, sealing prep
52
Factors to consider (5)
```
Esthetics
Economics
Medical Condition
Age
Caries risk
```
53
Dental Anatomy (4)
◦Enamel Rod orientation
◦Thickness of enamel and dentin
◦Size, location of pulp
◦Relationship of tooth to periodontium
54
Factors to consider (3)
* Caries
* Fractured teeth
* Improve form and function
55
Conservation of Tooth Structure
Repair damage but preserve vitality
56
Locations of Primary Caries (3)
pit and fissure
enamel smooth surface
root surface
57
Pit and Fissure occur from
imperfect coalescence of developmental enamel lobe
58
Area left unclean chronically
Enamel Smooth Surface
59
Locations of Primary Caries (3)
pit and fissure
enamel smooth surface
root surface
60
Locations of Primary Caries (3)
pit and fissure
enamel smooth surface
root surface
61
residual caries
caries left by operator (intentional or accident)
62
never ideal to leave caries, especially when left at the
DEJ or on prepared enamel wall
63
residual caries may be acceptable in rare instances to
avoid pulp exposure (when left has affected dentin near the pulp)
64
Recurrent Caries
Microleakage present at the junction between restoration and tooth
65
Recurrent Caries may progress under or behind restoration so it can't be
seen with a radiograph
66
Reparative Dentin
Formed by odontoblasts at end of tubules at surface of pulp
67
Reparative Dentin is formed in response to
irritation
68
rate of caries (2)
acute
| chronic
69
acute (3)
◦Or “rampant”
◦Light color
◦Appears dull, mushy
70
chronic (3)
◦Slow or arrested
◦Dark color
◦Appears shiny, solid
71
Dentists formerly practiced “extension for prevention.”
| This meant
taking away unnecessary tooth structure and is no longer practiced
72
Better preventative measures available (4)
Enameloplasty,
sealant,
preventive resin
or conservative composite restoration instead
73
Simple -
one surface involved
74
Compound -
two surfaces
75
Complex -
three or more surfaces of tooth involved
76
O =
occlusal
77
MO or DO or MOD -
mesial occlusal or distal occlusal, mesial-occlusal distal
78
F or B -
facial or buccal
79
L –
lingual
80
Internal Walls (2)
◦ Axial Wall
| ◦ Pulpal Wall or Floor
81
Axial wall is --- to long axis of tooth
PARALLEL
82
PULPAL WALL/FLOOR
wall closest to pulp
83
PULPAL WALL/FLOOR is --- to long axis of tooth in Class I and II preparations
PERPENDICULAR
84
Floor (4)
◦PREPARED (cut) wall
◦FLAT
◦PERPENDICULAR to occlusal forces
◦Pulpal and gingival floor/walls
85
Pulpal and gingival floors/walls provide (1) and distribute (1)
Provide stabilizing seats for restoration
| distribute stresses in tooth
86
Line Angle
Junction of two walls/surfaces along a line
87
Internal-
apex points AWAY from observer
88
External-
apex points TOWARD observer
89
Point angle
Junction of three surfaces
90
CAVOSURFACE angle or margin
◦ Junction of PREPARED cavity wall and EXTERNAL surface of tooth
◦ Keep in mind: location of tooth, direction of enamel rods, material you will be using
91
types of CAVOSURFACE angle or margin (3)
◦ Bevel
◦ 90 ̊
◦ Chamfer
92
CEJ◦ Cementoenamel Junction
◦ Where cementum meets enamel
93
Enamel Margin Strength is formed by
full length enamel rods
94
Enamel Margin Strength
Enamel rods’ inner ends are on sound dentin
95
UNSUPPORTED ENAMEL
When enamel rods are not
| supported by sound dentin
96
what to do with unsupported enamel
remove from prep, brittle and fracture easily
97
Classifications of Tooth Preparations name is based on
anatomy involved
98
Class I (2)
◦ Occlusal surface of posterior teeth
| ◦ May include lingual/buccal grooves and pits
99
Class II
◦ Proximal surfaces of premolars and molars
100
Class III
◦ Proximal surfaces of incisors and canines
| ◦ That do not involve incisal edge
101
Class IV
◦ (See Class III, add incisal edge)
102
Class V
◦ Gingival 1/3 of smooth surfaces
| ◦ Buccal, lingual
103
Class VI
◦ Incisal edge or cusp
104
Initial Stage (5)
* Outline Form
* Initial depth
* Primary resistance form
* Primary retention form
* Convenience form
105
Visualize OUTLINE FORM (2)
◦smooth and flowing
106
Undermined enamel ---
removed
107
--- placed where you can finish restoration
Margins
108
No --- on margins of preparation
occlusion
109
Preserve strength-
cusps and marginal ridges
110
Minimize extensions ---
faciolingually
111
Connect two preps that are
0.5
112
Class I- Depth of pit and fissure maximum --mm (in lab setting)
2.0
113
extend class 1 to
sound tooth structure
114
extend class 1 when (2)
◦ Fissures cannot be eliminated by enameloplasty
| ◦ Two cavities have <0.5mm between them
115
Do not terminate class 1 on (2)
cusp height or ridge crest
116
Allow sufficient access for class 1 (2)
placement and finishing
117
Class II- extend gingival margins ---, extend interproximal margins to ---
apical to contact
| embrasures
118
class 2 Axial Wall Depth
0.2-0.8mm INTO DENTIN
| ◦ 1.0-1.5 mm on manikin
119
Axial Wall Depth is measured from the
tooth (proximal surface) to the axial wall
| ◦ It is NOT a typical depth measurement from the top of something to the bottom
120
Enameloplasty
Remove shallow enamel fissure or pit
◦ Creates smooth, saucer shaped surface= self-cleansing
◦ NO MORE THAN 1/3 ENAMEL THICKNESS REMOVED
121
RESISTANCE TO FRACTURE
• Objectives are to resist fracturing the tooth or restorative material
122
Need to resist or withstand --- forces
occlusal
123
Conservative extension-
leave strong tooth
| • Remember dentin support
124
Preserve (2)
cusps and marginal ridges
125
When margin exceeds 2/3 of the distance between central groove and cusp tip
MUST CAP WEAK CUSPS
126
When margins end ½ distance between central groove and cusp tip
CONSIDER CAPPING WEAK CUSPS
127
Resistance Form (3)
* Internal line angles slightly rounded
* External line angles slightly rounded
* Accomplish with bevel at axiopulpal line angle
* = LESS STRESS CONCENTRATION
* Flat floors
* Prevents movement
128
Allow for sufficient thickness of restorative material
◦Amalgam ---mm minimum
◦Gold ---mm minimum depending on area
◦Porcelain ---mm minimum
1.5
1-2
2.0
129
Bevels when needed to (2)
◦ Remove unsupported enamel
| ◦ Reduce stress concentration
130
Margins- -- ̊ in amalgam
90
131
RETAIN THE RESTORATION
| ◦Objectives of this are to
keep restoration in the tooth
132
Dovetail prevents (2)
tipping and proximal displacement
133
retention form (3)
wall length
converenge
parallelism
134
Wall length
• Taller wall = resists pull of sticky foods
135
Convergence (2)
* Walls slant toward each other
| * Especially important with amalgam
136
retention form (3)
wall length
converenge
parallelism
137
What about bonded restorations? (2)
* Micromechanical retention between adhesive and tooth
| * Some of these principals become less important, but are still followed
138
Convenience Form
FORM THAT ALLOWS YOU TO ACCESS THE DEFECT
139
Convenience Form allows you to
see what youre doing, ideally with perfect ergonomics
140
Once outline form, primary resistance, and primary retention form are
complete, caries may
remain- REMOVE THE CARIES
141
Final stage of Tooth Preparation: (6)
* Remove remaining infected dentin
* Remove remaining old restoration
* Pulp protection
* Secondary resistance and retention forms
* Finish external walls and margins
* Final cleaning, inspecting, and sealing
142
Affected dentin-
demineralized
◦ Usually discolored but NOT soft
◦ OK to leave
143
Infected dentin-
microorganisms present
◦ Soft
◦ May or may not be stained
◦ MUST REMOVE. (there are MICROORGANISMS PRESENT.)
144
How to tell the difference between affected and infected dentin?
◦ Not always possible
145
Retention grooves, points
Areas for restorative material to “lock”into, results in improved retention
146
Secondary Resistance fewer
extensions
147
secondary resistance
| Bevel for rounded axiopulpal line angle to
increase bulk of restorative material, disperse concentration of forces
148
8:00 position (4)
◦ Slightly to the patient’s right and front
◦ Patient tilting head slightly to right
◦ Buccal sides of patient’s UL
◦ Lingual sides of patient’s LR
149
11:00 position (4)
◦ Slightly to the patient’s right and behind
◦ Patient tilting head slightly to left
◦ Buccal sides of patient’s UR
◦ Lingual sides of patient’s LL
150
12:00-1:00 position (4)
◦ Slightly to the patient’s left and behind
◦ Patient’s head tilted back
◦ Buccal sides of patient’s R and L anterior
◦ Lingual sides of patient’s R and L anterior
