Principles of Tooth Preparation (Pt. II)

Question 1

2)Resistance Form
• Features of a tooth preparation that enhance the ____ of a restoration and resist ____ along an axis other than path of placement
• Mastication and parafunctional activity subject prosthesis to substantial ____ and/or oblique forces
• Lateral forces tend to displace the restoration by causing ____ around the gingival margin
– Causing tipping of crown off preparation

Answer 1

stability
dislodgement
horizontal
rotation

Question 2

(2)Resistance Form 
• Adequate resistance depends on
– (a)\_\_\_\_ of the dislodging forces
– (b)\_\_\_\_ of the tooth preparation
– (c)\_\_\_\_ properties of the luting agent

Answer 2

magnitude and direction
geometry
physical

Question 3

(a)Magnitude and Direction of the Dislodging Forces
• In normal occlusion, biting force is distributed over all teeth, mostly ____
• A carefully fabricated fixed prosthesis has the load well distributed and favorably directed
• Different habits (ex. ____) apply oblique forces and axial forces
– Adequate resistance form essential

Answer 3

axially

bruxing

Question 4

(a)Magnitude and Direction of the Dislodging Forces

Force within margins, no ____ forces

Force outside margins, torque can ____ or rotate crown

Answer 4

lifting

tip

Question 5

a)Magnitude and Direction of
the Dislodging Forces

tensile stress: ____ from tooth

shear: ____ with the interface

shear and compression: ____ toward tooth

compression: ____ to tooth

Answer 5

away
parallel
angle
perpendicular

Question 6

(b)Geometry of Tooth Preparation
• Tooth preparation must be shaped so areas of axial wall prevent ____ of crown
• Resistance is a function of relationship between
– (1)____ taper – (2)____
– (3)____

Answer 6

rotation
axial wall
preparation diameter
preparation height

Question 7

(b) Geometry of Tooth Preparation
(1) Axial Wall Taper

• Resistance ____ as taper ____

Tangent line formed by connecting ____ of all arcs of rotation

Area above tangent line is ____

Answer 7

decreases
increases
tangent lines
resisting area

Question 8

(b)Geometry of Tooth Preparation (2)Preparation Diamete

• Resistance DECREASES as diameter ____
– Crown on narrower tooth has a shorter radius of rotation resulting in a lower tangent line and larger ____

  Resisting area is above the \_\_\_\_

Answer 8

increases
resisting area
tangent line

Question 9

(b)Geometry of Tooth Preparation (3)Preparation Height

• Resistance INCREASES as preparation height ____

In short prep, resistance is minimal because most of ____ is missing

Answer 9

increases

buccal wall

Question 10

(b)Geometry of Tooth Preparation
• ____ in healthy tooth structure are effective in enhancing resistance form because they interfere with ____ movement (tipping) of crown

Answer 10

grooves or boxes

rotational

Question 11

(c)Physical Properties of Luting Agent

• The higher compressive strength of luting cement, the higher ____ of cemented restorations

Answer 11

resistance

Question 12

(3)Preventing Deformation

• A restoration must have sufficient ____ to prevent permanent ____ during function or it will fail

Answer 12

strength

deformation

Question 13

(3)Preventing Deformation
• The change of form or shape of an object
• Prevention depends on: 
–(a)Adequate \_\_\_\_ 
–(b)\_\_\_\_

Answer 13

tooth reduction

margin design

Question 14

(3)Preventing Deformation (a)Adequate Tooth Reduction

• Sufficient bulk of material needed to withstand ____
• Functional cusp requires more ____ than non-functional cusp for ____
• Occlusal reduction should be as ____ as possible, following cuspal planes of teeth
– Ensures sufficient occlusal ____ and preservation of tooth structure

Answer 14

occlusal forces
reduction
strength
uniform
clearance

Question 15

(3)Preventing Deformation (b)Margin Design

• Tooth reduction should provide sufficient ____ for bulk of metal at margin to prevent distortion

Answer 15

room

Question 16

III. Esthetic Considerations

• Determine esthetic expectations of patient
• Esthetic considerations should not compromise the prognosis of the patient’s long-term ____ or ____

Answer 16

oral health

function

Question 17

PFM

Non functional cusp-\_\_\_\_mm
Non-Functional cusp bevel: \_\_\_\_mm length
functional cusp: \_\_\_\_mm
Functional cusp bevel: \_\_\_\_mm length
Lingual reduction: \_\_\_\_mm
Proximal reduction: \_\_\_\_mm
Facial reduction: \_\_\_\_mm
Shoulder: \_\_\_\_mm supragingival

Answer 17

1. 5
2. 0
3. 0
4. 0
5. 75-1
6. 3
7. 5
8. 5

Question 18

Full-metal prep

Non functional cusp-____mm
Non-Functional cusp bevel: ____mm length
Functional cusp: ____mm
Functional cusp bevel: ____mm length
Facial, lingual and proximal reduction: ____mm (after bevel)
Bevel: ____mm
Circumferential shoulder with bevel: ____mm supragingiva

Answer 18

1. 0
2. 0
3. 5
4. 0
5. 75-1.0
6. 5-1.0
7. 5

Question 19

• Functional cusp bevel
– On functional cusp
– Modified flat-end tapered diamond
– Parallel inward facing inclines
– 1.5mm reduction
– Extends between \_\_\_\_ angles

Answer 19

transitional line

Question 20

Steps in Crown Preparation • Occlusionreductiontabs
– ____mm (BLUE)
– ____mm (GREEN)
– ____mm (PINK)

Answer 20

2. 0
3. 5
4. 0

Question 21

Criteria for Evaluation
Cast Metal Preparation
• SAME AS CERAMO-METAL EXCEPT: • 1.5mm reduction for functional cusp
• 1.0mm reduction non-functional cusp
• Proper width of shoulder
– \_\_\_\_mm AFTER bevel and uniform
• Correct occlusal-gingival placement of shoulder
– 1.5mm supragingival
• Proper bevel width
• Proper bevel angulation
• Smooth bevel (can clearly be seen circumferentally) 
• \_\_\_\_ FITS INTERPROXIMALLY

Answer 21

0.75

perio probe