Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fixed Pros I > Principles of Tooth Preparation > Flashcards

Principles of Tooth Preparation Flashcards

1
Q

what are the 7 principles of tooth design and restoration design

A
  • preservation of tooth structure
  • retention form
  • resistance form
  • added preparation features
  • marginal integrity
  • structural durability of the restoration
  • preservation of the periodontium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

a crown preparation is an ______ surgical procedure

A

irreversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what biologic factors should we consider

A
  • dental pulp
  • gingival tissues
  • adjacent teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what injuries can occur

A
  • mechanical damage
  • temperature damage
  • chemical damage
  • bacterial damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

any time a bur touches a tooth, the pulp is _____

A

stimulated to respond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

a crown prep ____ the pulp

A

traumatizes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how do pulps respond

A
  • most respond with a healthy healing response
  • some respond by dying - necrosis
  • some remain hypersensitive with lingering pulpal inflammation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why is pulp responded in every crown prep

A

-decreased thickness of dentin remaining between prepared walls and pulp
- heat transferred to tooth during preparation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the vital core

A

a minimum of 1mm dentin surrounding pulp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are reasons crowns are placed

A

-esthetics
- prevention of catastrophic fracturing
- protection of root canal teeth
- make tooth stronger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what must be balanced

A
  • unnecessary destruction of sound tooth structure
  • preservation of the structural integrity of the remaining tooth strucure
    VS
  • mechanical requirements the patient needs
  • esthetic requirements the patient desires
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is morphological reduction

A
  • preservaton of the basic primary tooth anatomy within the preparation (axial wall and occlusal anatomy)
  • leaves the maximum thickness of residual tooth structure surrounding the pulp
  • leaves anti- rotational features retentive and resistive features in the tooth preps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is retention

A

prevention of removal along the path of insertion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is retention created by

A

two opposing vertical surfaces with converging surfaces held to within certain parameters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does cement do for retention

A

offer frictional resistance to dislodgement
- a shear stress aiding in retention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what mechanical factors provide retention

A
  • dental cements hold through mechanical interlocking of projections of cement into irregularities of the surfaces being joined
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is resistance

A
  • prevention of restoration being dislodged by apical or oblique forces
  • through occlusal forces and lateral forces not along the path of insertion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the greatest determining factor in a crowns dislodgement

A

resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

resistance is built into a preparation by forming walls to block anticipated movement due to:

A
  • leverage
  • rotation (vertically or horizontally)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what factors can affect the resistance form of a tooth prep

A
  • total occlusal convergence (TOC)
  • preparation wall length
  • tooth width after preparation
  • geometric forms
  • surface area of the tooth prep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how do geometric forms affect resistance

A
  • limit the paths of insertion
  • grooves, boxes, vertical planes, pins
  • morphological reduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is total occlusal convergence

A
  • the angle of convergence of taper between two opposing walls of a tooth prep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is inclincation

A

the angle of convergence of taper of one wall of a preparation in relationship to the long axis of the preparation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the ideal TOC

A

6 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what convergence will a tapered diamond make if the shank of the bur is held parallel to the intended path of insertion

A

2 or 3 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

two opposing surfaces each with 3 degrees taper, add together for an overall TOC of ____

A

6 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the crown prep feature most under operator control

A

TOC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

as occlusal convergence increases, retention _____

A

degreases

29
Q

what is the max crown retention

A

around 5 degrees

30
Q

approximately _____ retention when TOC is 20 degrees

A

1/5

31
Q

what is the average TOC of prepared teeth

A

10-20 degrees

32
Q

molar tooth preps have ____ TOC than premolars or anterior teeth

A

greater

33
Q

mandibular tooth preps have ____ TOC than maxillary tooth preps

A

TOC

34
Q

why do mandibular and molar preps have larger TOC

A

challenges in access and visibility

35
Q

posterior preps are generally _____ with _____ occlusal forces

A

shorter; higher

36
Q

posterior preps require _______ TOC than anterior teeth to facilitate ______

A

more angled TOC; crown seating

37
Q

the greater the height of the tooth preparation wall, the _____ the retention of the restoration

A

greater

38
Q

why does increased height increase retention

A

increases the area of cementation

39
Q

for every 1mm increase in wall height, the retention and resistance form increases up to ______

A

10%

40
Q

the wall height should be greater than the _______

A

tipping arc of displacement

41
Q

the shorter the prep, the____ the taper ____ be

A

less’;MUST

42
Q

the taller the prep, the ____ the taper _____ be

A

greater; MAY

43
Q

a narrow tooth with a smaller diameter prep can have ________resistance than a wider, larger diameter tooth when they both have the same wall height

A

greater

44
Q

why does a narrow tooth with a smaller diameter prep can have greater resistance than a wider, larger diameter tooth when they both have the same wall height

A

small tooth has a shorter rotational radius for the arc of rotation (tipping arc)

45
Q

ideal and adequate resistance and retention , the height/width ration should be greater than ____ for all teeth

A

0.4

46
Q

what are the wall height ideals when prep is within TOC for molars? incisors and premolars?

A

-molars: 4 mm
- incisors and premolars: 3 mm

47
Q

how is resistance form assesses

A
  • measure TOC between two opposing walls
  • measure wall height parallel with long axis
  • measure tooth width ratio
48
Q

what modifications can you make to the prep to increase the resistance

A
  • decrease the TOC with axial re-shaping of prep walls
  • addition of grooves/box forms
  • increase wall height
49
Q

how can you increase wall height

A
  • lower margin
  • add wall height with core build up
  • crown lengthening surgery
  • orthodontic extrustion
50
Q

what can you do if your TOC is not ideal or your wall height is less than ideal

A
  • add geometric forms such as a box, groove, pin hole
51
Q

grooves or box forms must have a _______

A

definite wall perpendicular to the direction of the displacing force

52
Q

describe the surface area of tooth preps

A
  • retention is increased with increased surface area
  • increasing surface area helps with retention but it is not as important as TOC parameters and the height/width ratio
53
Q

how do you define high marginal integrity

A
  • fits as closely as possible to minimize cement film width (25 microns)
  • sufficient strength to withstand forces of mastication
  • located where dentist can finish and inspect and patient can clean
54
Q

what happens if the margins are not as closely adapated to the finish line of the prep

A
  • microleakage
  • recurrent caries
  • possible de- cementation of restoration
55
Q

tooth prep finish line:

A
  • needs to be conservative of tooth structure
  • readily identifiable on tooth, impression and die
  • provides sufficient bulk of restorative material
56
Q

the size of your finish line determines:

A
  • the bulk of material at the margin
  • the fit of the restoration
57
Q

morphological reduction:

A

adequate occlusal/incisal reduction and clearance without excessive removal
- uniform thickness of restoration material
- parallels the major planes of the tooth
- no pulpal involvement

58
Q

what are prep features that contribute to structural durability

A
  • occlusal/ incisal reduction
  • functional cusp bevel
  • axial reduction
59
Q

what does axial reduction do

A

creates space for an adequate bulk of material within normal contours of the tooth

60
Q

what happens when there is not enough axial reduction

A

thin restoration walls- difficult to finish and possible loss of strength

61
Q

what happens when there is too much axial reduction

A

thick over contoured walls- plaque trap and periodontal inflammation

62
Q

what happens if our prep does not leave room for structural durability

A
  • fracture of restoration
  • grind through porcelain to adjust occlusion
  • crown worn through due to thin material
63
Q

our crown prep and final restorations should promote periodontal healthy by:

A
  • placement of margin for cleanse ability
  • marginal smoothness and crown adaptation
  • axial contours and emergence profile
64
Q

what are the margin guidlines

A
  • place margin where dentist can finish and evaluate
  • place margin where patient can clean
  • place margin where margin can be recorded during impression taking
  • place margin on enamel when possible
  • place margin supra gingival when possible
  • make margin as smooth as possible
65
Q

what is important to keep in mind in preservation of tooth structure

A
  • pulpal integrity
  • morphological reduction
66
Q

what is important to keep in mind in resistance and retention

A

-TOC
- wall length
- tooth width
- geometric forms
- surface area

67
Q

what is important to keep in mind in marginal integrity

A

finish line
- margin

68
Q

what are the types of finish lines

A
  • feather edge
  • knife edge
  • chamfer
  • bevel
  • shoulder
  • beveled shoulder

Fixed Pros I (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions