Class IV Flashcards
2.. Prepare fractured lesion in class IV
angle, 2/3’s away from the incicsal corner.
Pulp of maxillary incisors in permanent vs primary:
- Place Gingival Margin in class IV
- what bur should you use?
- what technique is used and what are you tying to achieve?
use flame/tapering bur to place gingival margin bevel
- BEVEL: if enough enamel (more than 0.5mm). angle 45 degree
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
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.
When doing a chamfer bevel in palatal margin how should you position bur?
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
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
Summarise steps of Class IV
- clean, contact, colour
- slice 2/3
- bevel gingival
- chamfer palatal
- 2 bevels labial: taper + wavy
colour
slice
prox
palatal chamfer
front 2 Bs
In Black’s classification of carious lesions, a Class IV lesion
is one that:
occurs on the proximal surface of an anterior
tooth AND extends to include an incisal corner.
In restoring Class IV lesion with composite resin (CR), it is
common to
- Prepare/modify a cavity
- Place a GI lining to protect pulp in deep cavities
- Apply a resin bonding agent
- Apply a matrix and wedge
- Place composite resin
Clinical Scenario
Class IV restorations are most commonly required
following one or more of the following:
- 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
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:
- “Four surface anterior adhesive restoration, restoring one incisal corner” (in Aust Dent Assoc
terminology) - Item 524 or Item 578 – restoration of an incisal
corner (in Aust Dent Assoc item numbers)
When restoring a Class IV situation, the specific goals of
treatment are:
To restore function
* To restore aesthetics
Clinically, Class IV restorations are very variable in size
and shape. For preclinical work, in simulating a typical
clinical situation
- A SIMULATED fracture lesion is first prepared
- 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”) - This is then restored
Class IV Pre-Restorative Preparation and Assessment
For both clinical and pre-clinical work, before
commencing
- 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.
Class IV- To simulate a typical, fractured tooth:
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
Labial Margin Class IV
a) how many bevels must you do?
b) technique for bevel 1?
c) shape of bevel 2?
2
gentle wipes
wavy
Proximal view of class IV
Steps for Class IV
