class IV restoration Flashcards
what is a class IV lesion?
- what can they be casued by
a proximal lesion of anterior teeth that involves one or more incisal angles
- trauma, carries, occlusal interferences and grinding
what MUST you do before starting the restoration
Evaluate occlusion
what shade of composite do you use?
- when should you choose the shade?
- Multiple shades and opacities may be required to properly restore
and match existing tooth structure (gingival vs. incisal shading)
\ - prior to beginning in proper light
Classification of fractures:
Historically done according to the _______ __ ____ _______?
extent of the fracture ( Ellis classifications)
Class I
- what tooth material is affected
- how is pulp affected
- why may the retention for the restoration be challenging?
- Class I : in enamel only
- Best pulpal prognosis
- due to occlusion, etc
Class II
- what tooth material is affected
- how is pulp affected
- how can be restored
- extends through enamel and dentin
- Risk of pulpal
involvement long term
increases (due to
original trauma) - Can be restored with
direct composite,
veneers or crowns
Class III
- what tooth material is affected
- how is pulp affected
- how is it restored
- extends through enamel
and dentin and exposes pulpal
tissue clinically - Minimally requires pulpal protection prior to restoration
- Need for root canal therapy
dramatically increases - Restoration may be with direct
composite, but long term may
require a crown (especially if root
canal therapy is indicate
What are other non class IV lesions
A. Non vital tooth without loss of
tooth structure
b. Total tooth loss (Avulsion)
c. Displacement of tooth without
fracture of crown or root
d. Fracture of entire crown
what should you consider prior to treatment with TRAUMA?
- Must evaluate for other injuries if tooth fracture is due
to trauma (lacerations, head injury, jaw fractures, etc) - Must evaluate tooth for vitality and if vital, must
periodically re-test vitality as tooth can become nonvital in the future. - Radiographic exam a must! Evaluate for widened
PDL, caries, root fractures - Discuss treatment options with patient (include risks
and benefits, longevity, esthetics, finances, need for
future root canal therapy)
what do you need to consider prior to the treatment ( pt2)(5)
- Must consider nature of injury (caries, trauma,
grinding) - Consider need for root canal therapy now or in the
future - Must consider preparation design (need for retention,
pulpal protection, esthetic design-bevel) - Consider best restorative material (direct composite,
veneer, crown) - Must evaluate patient occlusion
what complications should you consider
- Retention when too much of
clinical crown is missing - fracture
is not large enough
-if occlusal
interferences complicate
what are some bite complications you should consider
- Class I, II, III or open bite
- Lateral or protrusive
interferences - Severely worn dentition
(Bruxism) - Collapsed bite
what is bruxism
severely worn dentition
what are some considerations for young pts
- what may you consider
- “Young” tooth will
have a large pulp
chamber and high pulp horns - The tooth’s apex may not be closed and will require treatment prior
to root canal therapy - Might consider pulpal
protection even in a
moderate fracture
(Calcium Hydroxide asa liner; Glass Ionomer
as a base)
what are some considerations regarding the pulp?
- what can you see in a radiograph
- what may pulp trauma require
Recognize signs of
pulpal injury from
trauma
1. Receded pulp
2. Widened
PDL/Periapical
Periodontitis
May require root canal therapy. Tooth may clinically present with a
darkened color
According to what is the preparation shaped
- shaped according to the extent of the fracture in a natural tooth
where is the retention placed?
- where do you bevel?
- Note that retention is placed
internally in the dentin area,
and the entire external cavosurface margin has a
continuous bevel (facial, lingual, incisal and margins).
NOT GINGIVAL:
with what bur should you remove the dentin and at what length
- 35 carbide bur
- 1mm
what are the steps for a class IV prep
1) Follows outline form of the
fracture
2) ½ mm into dentin (35 carbide bur)
3) Smooth internal surfaces (hatchet and hoe)
4) Retention at the axio-gingival
line angle and at the axioincisal point angle (1/2 roundbur)
5) 1 mm bevel around the facial,
lingual and incisal margins (tapered diamond bur)
(NOT GINGIVAL
what should you do before bonding? what are the steps
- etch
- acid etch the enamel for 30 seconds
- wash the preparation with water for 30 seconds
- dry the enamel of the preparation with air (do not desiccate
the dentin)
what are the steps for applying the bonding agent
- Pop the bonding agent and
pick up a small amount of the
bonding agent with the end of
the applicator - Apply the bonding agent to
the tooth by “rubbing” the
applicator onto tooth surface
for 20 seconds - Air thin any excess bonding
agent with the air syringe - Cure the bonding agent for 20
seconds
where should you place a mylar strip and wedge
- Place a Mylar® strip interproximally,
and place a wedge tightly from the
lingual embrasure to hold the strip
against the tooth - make sure the wedge is in tight enough so that the strip cant move
how do you choose a wedge size and what is the goal of placing a wedge
Wedge sizes vary (must chose
according to size of embrasure with
the goal to seal the gingival margin
and prevent an overhang of
composite)
what is the matrix material
A polyvinyl siloxane putty material is used to produce the lingual
matrix
