2. Stainless steel crown
is a semipermanent
restoration used in the
primary & young
permanent teeth
Stainless steel
crowns(PMCs), for
primary molar teeth were
first described in 1950 by
Engel, followed by
Dr.William Humphrey
(1950)
3. It is more frequently used in deciduous dentitions
than in permanent
In small deciduous teeth, neglected caries
can destroy the tooth.
4. Advantages
They are far superior to the multisurface
amalgam restorations with respect to both life
span and replacement
5. They are acceptable to both patient and
dentists
They are also more cost effective (simple
procedures involved in restoring even
severely affected primary molars)
6. The tooth preparation
needs minimum
reduction.
The stainless steel crown
placement can be done in
single appointment so its
not time consuming
procedure.
These are available in
prefabricated so it saves
the time.
7. INDICATIONS
Restoration of primary or
young permanent teeth with
extensive carious lesions.
Restoration of hypoplastic
primary or permanent teeth.
Restoration of primary teeth
following pulpectomy or
pulpotomy procedures.
8. Restorations in disabled individuals or in
whom oral hygiene is poor and failure of other
materials is likely.
As an abutment for space maintainers or
prosthetic appliances.
Temporary restoration of a fractured tooth.
In severe cases of bruxism
Single tooth crossbites
12. Types
Based on shape
UNTRIMMED CROWNS :-
These crowns neither trimmed
nor contoured require lot of
adaptation these are time
consuming
e.g. Rocky mountain
PRETRIMMED CROWNS :-
These crowns have straight,
non-contoured sides but
festooned to follow a line
parallel to the gingival crest they
still require contouring and
some trimming
e.g. Unitek stainless steel
crowns
13. PRECONTOURED
CROWNS :-
These crowns are
festooned and are also
pre-contoured though a
minimal amount of
festooning and trimming
may be necessary
e.g. Ni-Chromium crown
Unitek stainless
steel crowns
14. CLINICAL STEPS
PRE-OPERATIVE CROWN EVALUATION
CROWN SELECTION
L.A. ADMINISTRATION
RUBBER DAM APPLICATION
PLACEMENTS OF THE WEDGE
TOOTH PREPARATION
TRIAL FITTING
FINAL FINISHING AND POLISHING
CEMENTATION OF THE CROWN
POST CEMENT INSTRUCTIONS
15. In crown selection
Mesiodistal width of the tooth
Occlusal anatomy
Height of the crown
17. TOOTH PREPARATION
: The aims of the tooth reduction are :-
To provide sufficient space for the
steel crown
To remove the caries
To leave the sufficient tooth
structure for retention of crown
18. The tooth reduction is done in 3 stages
1.Occlusal Reduction
2.Proximal Reduction
3.Bucco-lingual Reduction
1)OCCLUSAL REDUCTION :-
Occlusion reduction is done with bur No 330
or tapered diamond, A 69 or 169 L
Reduce the occlusion by 1.0– 1.5 mm and reduce
along the cusps to get the tooth anatomy
The reduction of the occlusal surface can be judged by
comparing the marginal ridge of the adjacent tooth
Sharp line angles should be rounded
19. 2)PROXIMAL REDUCTION
This done by using bur No 169 L,69L
The bur is moved in a buccolingual direction starting
from the occlusal surface
The contacts must be completely opened
Avoid the damage to the adjacent tooth(1-2mm away)
Depth is just below the contact and any proximal caries
should be involved
20. Care should be taken
that not create the ledge
which would make the
placement of crown
difficult
21. BUCCO-LINGUAL REDUCTION
Minimal but adequate reduction is necessary
Natural undercuts of these surfaces assists
the retention of the stainless steel crowns
On first primary molar in some cases,it is
necessary to reduce the large buccal bulge
If the crown is over reduced, the crown fits
poorly to the tooth
22.
23. Evaluation criteria
Occlusal clearance
Proximal slices converge toward the occlusal &
lingual
An explorer tip should pass between the prepared
tooth & proximal tooth at gingival margin
Buccal & lingual reduction :-0.5mm
Buccal & lingual converge occlusally
24. TRIAL FITTING AND TRIMMING
Try the crown on the tooth
First place the crown from lingual side and rotate it
towards the buccal side
The position of the gingival margin is marked
subgingivally
The excess material is then cut with crown and
bridge scissor
The margins are smoothened using green stone
Then the crown is contoured & crimped
The crown should extend 1mm below the gingiva
25. To prevent any type of accidental inhalation
of the crown due to slippage,
Soldering a hook on the lingual aspect of crown to
which floss is tied
Soldering a lingual attachment to which floss is
tied
Attachment of floss to crown structures on the
buccal aspect by special glues. This is the best
method as it provides no interference during
crown manipulation
26. Using No 114 plier recontour the
gingival third of the crown
With No 800-417 crown crimping
pliers bend the margins gently so
as to fit in the under cuts
Retry the crown in a lingual buccal
direction, it should snap into
position under firm finger grip
With the explorer check all the
margin adaptation, where there is
open margin crimp it with the plier
and retry the crown
27. FINISHING AND POLISHING
Use the large green stone make a knife edge
finish at cervically
Rotation of the stone should be toward & at a
450 angle to the edge of the crown
Smooth and finish the margin with rubber wheel
to remove scratches & to obtain shine
Remove the rubber dam
Try it on tooth and check the occlusion
28. CEMENTATION OF THE CROWN
For cementing the crown many
types of cements are used
Zinc phosphate cement
Polycarboxylate cement
Glass ionomer cement
Zinc oxide eugenol
Among these the GIC is most
preferred for crown, Zinc oxide
eugenol is least preferred
The tooth surface is flushed
with water to remove dentinal
debris and isolated with cotton
29. Apply petroleum jelly to contact areas before placement
of the cementation it helps in easy removal of the excess
cement
Fill the ½ to 2/3rd of crown with the cement which should
be mixed in luting consistency
Seat the crown from lingual side and then to the buccal
side, ask the patient to close into centric occlusion
,before the cement sets
Remove the excess cement with a scaler or explorer
carefully , because excess cement cause the
inflammation of gingiva
30.
31.
32. Rinse the oral cavity & before dismissing the
patient,reexamine
33. Post insertion instructions
Patient should be instructed to avoid heavy
chewing with the crown for 24 hours.
Instructions should be given for maintaining
oral hygiene.
The patient should be recalled once every 6
months for evaluation
34. CAUSES OF STAINLESS STEEL
CROWN FAILURES
Poor tooth preparation
Poor crown adaptation leads to poor retention
Improper cementation methods
Failures of pulp treatment
Recurrent caries mainly in the inter-proximal area
35. COMPLICATION OF STAINLESS
STEEL CROWNS
INTERPROXIMAL LEDGE
Incorrect angulations of the tapered fissure bur can
produce a ledge instead of a shoulder
any attempts made to correct the ledge is done carefully
which may cause the pulp exposure
CROWN TILT
Destruction of a complete lingual or buccal wall by
carious leads to tilting of the crown to the deficient side
this is due to lack of support
It can be avoided by placing the amalgam or GIC on
deficient side which provides the support
36. POOR MARGINS
The marginal integrity of the crown is reduced when it is
imperfectly adapted
The accumulation of plaque leading to inflammation
INHALATION OR INGESTION OF THE CROWN
The crowns may be aspirated or ingested
to avoid this hold a gauze piece on lingual/palatal side
while placing the crown
If the crown is ingested it can be removed by holding the
child upside down as soon as possible
If not possible seek the medical help immediately
37. Clinical modifications
1) Adjacent stainless steel crowns :-
According to (Nash, 1981):
Prepare the occlusal reduction of one tooth
completely before beginning the other as
there is a tendency to under reduce both
when reduction on them is done
simultaneously.
38. 2)When a stainless steel crown and a Class II
amalgam restoration are to be done at one
appointment
The stainless steel crown preparation and any needed pulp
treatment should be done first
Then adapt and cement the crown.
The Class II cavity preparation is also done at the same
time to allow for proper contour of the stainless steel crown's
marginal ridge with the indicated amalgam restoration.
After the crown is cemented, clean the excess cement from
around the crown.
Replace the rubber dam, and adapt and wedge a matrix
band.
Insert an amalgam restoration.
The stainless steel crown is used as a guide in reproducing
the anatomy and morphology of the silver amalgam
restoration
39. 3)Adjacent stainless steel crowns
with arch length loss (McEvoy, 1977)
Extensive and long-standing carious
lesions can cause a shift of primary teeth
into the interproximal contact areas
With this mesiodistal dimension loss, it is very
difficult to restore the lost arch length.
40. Flatten the contacts of the crowns using
a No. 110 pliers.
When the crowns are cemented, the
marginal edges should be aligned.
Before cement setting, use a Howe No.
110 pliers to obtain optimum alignment if
necessary .
42. Reverse stainless steel crowns
To correct lingual crossbite
of maxillary incisor tooth
When placed on the
affected incisor in a
reversed position, it will
create its own inclined
plane and produce a
functional contact and a
leverage force
43. Open-faced Stainless steel crowns
Used in childrens with
rampant
caries(Hartmann,1983
Helpin,1983)
Not so esthetic,but
there is increased
functional stability.
