Class IV

Question 1

2.. Prepare fractured lesion in class IV

Answer 1

angle, 2/3’s away from the incicsal corner.

Question 2

Pulp of maxillary incisors in permanent vs primary:

Answer 2

Question 3

3. Place Gingival Margin in class IV
   - what bur should you use?
   - what technique is used and what are you tying to achieve?

Answer 3

use flame/tapering bur to place gingival margin bevel
- BEVEL: if enough enamel (more than 0.5mm). angle 45 degree

Question 4

In Class IV preps, fter
2. lesion prepped
3. Bevel at GM placed

What must you do next and why?
What measurement and technique is used

Answer 4

Prep Palatal margin
- pop a chamfer on palatal (not front, doesn’t look good): a lil sitting space for bulk of composite
- Chamfer is abt 1-1.5mm down gingivally
- extend from prox gingival and down incisal (DONT GO TO EDGE)
- bur: long axis of tooth.

Question 5

When doing a chamfer bevel in palatal margin how should you position bur?

Answer 5

Question 6

In Class IV preps, after
2. lesion prepped
3. Bevel at GM placed
4. Chamfer on Palatal margin

What must you do next and why?
What measurement and technique is used

Answer 6

Prep labial margin
- bevel 45 degrees from tooth sf, gentle wipes

BEVEL 1
- 3/4 enamel thickness slowly taper off with no thickness
- 1mm beyond fracture line

BEVEL 2
- wavy finish, bevel another 1- 1.5mm further down tooth

Question 7

Summarise steps of Class IV

Answer 7

1. clean, contact, colour
2. slice 2/3
3. bevel gingival
4. chamfer palatal
5. 2 bevels labial: taper + wavy

colour
slice
prox
palatal chamfer
front 2 Bs

Question 8

In Black’s classification of carious lesions, a Class IV lesion
is one that:

Answer 8

occurs on the proximal surface of an anterior
tooth AND extends to include an incisal corner.

Question 9

In restoring Class IV lesion with composite resin (CR), it is
common to

Answer 9

1. Prepare/modify a cavity
2. Place a GI lining to protect pulp in deep cavities
3. Apply a resin bonding agent
4. Apply a matrix and wedge
5. Place composite resin

Question 10

Clinical Scenario
Class IV restorations are most commonly required
following one or more of the following:

Answer 10

• Weakening and loss of an incisal corner following proximal caries
• Failure of an existing Class III restoration with involvement of the incisal corner of the tooth
• Trauma to an anterior tooth with fracture of the incisal corner

1.caries
2. failed 2nd
3. trauma

Question 11

Because there can be clinical variation in the size and
number of surfaces to be restored in a Class IV restoration,
descriptions of these in Australian Dental Association
terminology will depend on:
* The number of surfaces restored
* The number of incisal corners restored
A typical Class IV restoration might be described:

Answer 11

1. “Four surface anterior adhesive restoration, restoring one incisal corner” (in Aust Dent Assoc
   terminology)
2. Item 524 or Item 578 – restoration of an incisal
   corner (in Aust Dent Assoc item numbers)

Question 12

When restoring a Class IV situation, the specific goals of
treatment are:

Answer 12

To restore function
* To restore aesthetics

Question 13

Clinically, Class IV restorations are very variable in size
and shape. For preclinical work, in simulating a typical
clinical situation

Answer 13

1. A SIMULATED fracture lesion is first prepared
2. This “fracture lesion” is then modified, according to
   the needs of CR and in order to optimize function
   and aesthetics, by margin preparations (“finishing
   lines”)
3. This is then restored

Question 14

Class IV Pre-Restorative Preparation and Assessment
For both clinical and pre-clinical work, before
commencing

Answer 14

• Contacts on this tooth, and on adjacent teeth, from
  the opposing teeth, are identified (for reference during the “finishing” stages of the restoration),
• The shade/colours of the CR are selected. (In preclinical work, commonly only one shade will be
  used. Clinically, however, several shades may be selected in order to harmonise and blend in with
  the adjacent teeth).
• If required clinically, a “trial” or “mock” restoration may be placed to confirm shade.

Question 15

Class IV- To simulate a typical, fractured tooth:

Answer 15

A slice is prepared, for preclinical work, this slice
extends:
* From approx. 2/3 to ¾ of the way across the incisal edge of the tooth;
* To within approx. 1 to 1.5mm of the CEJ (of the extracted tooth). This extension should be gingival
to the contact region.
* To prepare this simulated “fracture lesion”, a long
tapered or cylindrical bur is used. Care is taken to avoid touching the adjacent tooth

Question 16

Preparation of the Margins for Class IV
1. Incisal Edge

Answer 16

For both clinical and preclinical work, NO FURTHER preparation is carried out at the incisal
edge of the “fracture line” (that is, the incisal extent of the fracture). This margin is already
“bevelled”, and any further preparation would
provide even less bulk of CR on the load-bearing
incisal edge of the restoration.

• All other margins are prepared in order to enhance either longevity or aesthetics or both
  longevity and aesthetics.
• According to the location of the margin, a bevel is
  often placed.

Question 17

When do you place a gingival margin in class IV? what technique is used?

Answer 17

If sufficient (>0.5mm thickness) enamel is present,
a bevel is placed at approx. 45° to the tooth
surface.
* A flame-shaped or tapering diamond point, with a fine point, is commonly used to place this bevel. Care is taken to avoid touching the adjacent tooth.

Question 18

Palatal Margin Class IV: What technique is used. Describe differences when margin is in contact vs not in contact with adjacent tooth:

Answer 18

1. A “bevel” margin (at 45° angle, 0.5-2.0mm wide) is ONLY prepared if margin is not in contact with antagonist.

2.Chamfer is prepared if the fracture line is in contact
area with the antagonist teeth

Question 19

Labial Margin Class IV

a) how many bevels must you do?
b) technique for bevel 1?
c) shape of bevel 2?

Answer 19

2
gentle wipes
wavy

Question 20

Proximal view of class IV

Answer 20

Question 21

Steps for Class IV

Answer 21