Lecture 12

Question 1

Indications for Class II lesions?

Answer 1

Occlusal and proximal contacts, existing restorations

Question 2

How to achieve tight contacts:

Answer 2

pre-wedge or ring, also promotes more conservative preparation

Question 3

How to achieve ideal proximal wall contours:

Answer 3

anatomical sectional matrices

Question 4

Why not to use a matrix band with resin composite:

Answer 4

it creates a flat proximal surface and can’t hold the matrix band in close adaptation to the adjacent tooth.

Question 5

How to achieve intimate gingival margin seal:

Answer 5

good wedging or flowable composite

Question 6

How to get matrix band in contact with adjacent tooth:

Answer 6

burnish the matrix

Question 7

What to be cautious of when burnishing the matrix?

Answer 7

not to scratch the matrix band, use a round contoured instrument

Question 8

True or False? Single placement of wedge is most effective.

Answer 8

F. Multiple wedging is better (reapplying seating pressure several times throughout procedure.

Question 9

Beyond the initial damage why is the destruction of adjacent tooth structure so detrimental?

Answer 9

more likely the damaged surface will require subsequent restoration

Question 10

Alternate method to protect proximal surfaces:

Answer 10

Interguard (Ultradent), FenderWedge (Garris Dental Solutions) for simultaneous preweding and protection of the adjacent tooth

Question 11

Instrument for protecting proximal surfaces during preparation:

Answer 11

special diamond preparation tip, diamond abrasive only on one side of tip, sonic handpieces that fit dental unit couple or piezoelectric ultrasonic unit used for SRP

Question 12

True or False? Pulp temperature increases more with ultrasonic preparation than with water-cooled rotary preparation.

Answer 12

F. Not greater than

Question 13

How does sonic preparation adversely affect adhesion compared to rotary handpiece preparation with a carbide bur?

Answer 13

It does not

Question 14

Methods to remove proximal wall in a Class II preparation:

Answer 14

safe-side diamond tip or spoon excavator to fracture and remove thinned enamel (fine-ri diamonds or carbide finishing burs for bevels)

Question 15

When is a bevel not necessary on the F or L, proximal surface of a Class II preparation?

Answer 15

When preparation exits the external tooth surface at an obtuse angle

Question 16

Benefit of bevel when using adhesive agent and resin composites:

Answer 16

more area for acid etching and bonding

Question 17

Functional purpose of beveling in general:

Answer 17

to expose enamel rods transversely, more effective etching pattern.

Question 18

True or False? Etching of longitudinal cut enamel rods will result in the most effective bond.

Answer 18

F. Transversely exposed rods (beveled Class III)

Question 19

How do enamel rods exit tooth surfaces?

Answer 19

approximately right angles to external tooth surface

Question 20

Why must an obtuse angle be formed in Class II preparation on proximal surface?

Answer 20

to expose ends of enamel rods

Question 21

On which surface margins of the proximal box should bevels be placed?

Answer 21

F and L cavosurface margins (makes margins more accessible for finishing and polishing and reduces marginal leakage)

Question 22

If the preparation exits tooth at an obtuse angle, should a bevel be placed?

Answer 22

no

Question 23

When not to bevel:

Answer 23

within 1.0 1.5mm of CEJ (or apical to CEJ) or not an adequate band of enamel remaining

Question 24

What type of enamel is found near the CEJ?

Answer 24

prismless

Question 25

Why not to bevel near CEJ:

Answer 25

thinner enamel, beveling increases the potential for removing the little enamel that remains, acid etching of prismless enamel is ofter less effective

Question 26

At what distance from the CEJ is adhesion no better than bonding to dentin?

Answer 26

within 1 mm of CEJ

Question 27

Inverse or internal bevel:

Answer 27

leaving enamel that is not supported by dentin at the gingival cavosurface margin

Question 28

When should enamel with no supporting dentin NOT be removed in preparation?

Answer 28

Class 2, at the gingival cavosurface margin

Question 29

Why is leaving unsupported enamel indicated for Class 2 preparations at gingival cavosurface margins?

Answer 29

reduces microleakages compared to butt margin, better than making a margin on or near the CEJ

Question 30

How does an inverse bevel help with adhesion?

Answer 30

exposes enamel rods for etching on their internal ends, better adhesion to the gingival margin

Question 31

On which surface is a bevel not indicated?

Answer 31

occlusal, normal preparation: end-cut rods because of the orinetation of the enamel rods in cusp inclines

Question 32

Benefits of not beveling on occlusal surface:

Answer 32

conserve tooth, decreases the surface area of the restoration, lessens the chance of occlusal contact on the restoration, eliminates thin area of resin composites that would be more susceptible to feature ad wear, and well-demarcated marginal periphery to which resin composites can be finished more precisely

Question 33

Survivability of posterior resin composite restorations is the directly related to:

Answer 33

the proportion of the occlusal surface restored (increased be beveling)

Question 34

Placing a glass ionomer, RMGI, or bonded composite under unsupported enamel will make the above enamel as strong as it was when supported by dentin.

Answer 34

F. weaker

Question 35

What are cavity liners composed of?

Answer 35

calcium hydroxide

Question 36

When to use cavity liner:

Answer 36

very close to pulp and if there is a possibility of a minute plural exposure

Question 37

When to use cavity liner over extensive area of dentin:

Answer 37

DO NOT. provides no benefit both e pulp and decreases the surface area of dentin available for adhesion, dissolution of the liner during acid etching can interfere with a sound bond to enamel and dentin

Question 38

When is a glass-ionomer liner indicated?

Answer 38

deeper preparation, gingival margin approaches or extends beyond the CEJ

Question 39

Mechanical advantage to glass-ionomer liner:

Answer 39

bond to both tooth structure and overlying resin composites AND introduces less polymerization stress into tooth structure than resin composite

Question 40

Long-term advantage of glass-ionomer liner for posterior restoration:

Answer 40

fewer secondary caries, release fluoride into adjacent tooth structure