Pediatric Dentistry I Forth Year

1. Steps for ST St C
• Prefabricated crowns form
• Adapted to individual teeth
• Cemented on teeth with a biocompatible
luting agent
• Used mainly to preserve primary teeth till
the normal age of exfoliation
• Can be used newly erupted permanent or
(immature tooth) as a semi permanent
restoration

2. Use of Stainless Steel Crowns
u Introduced to pediatric dentistry by Dr. William
Humphrey in 1950
– prior to that orthodontic bands filled with
amalgam were a last resort
– “necessity is the mother of invention”
u Considered superior to large multisurface
amalgam restorations and have a longer clinical
lifespan than two or three surface amalgams
(Dawson et al., 1981)

3. Success of the stainless steel
crown
• The quality of the tooth preparation
• Selection and adjustment of the of an
appropriate crown
• The luting cement

4. Indications
u Extensive caries
u Pulpotomy/pulpectomy
u Malformed teeth
u Fractured teeth
u Severe attrition of primary teeth
u Mesial lesions on first primary molars
u Semi-permanent restorations on young
permanent molars

5. Contraindications
u Esthetics
u Teeth that are nearing exfoliation
u Mechanical problems
– space loss
– caries beneath the level of the bone
u Permanent restoration in the permanent
dentition

6. Types of SSC
• 1- Non contoured
untrimmed crown
They has straight
sides
They are longer than
the length of the teeth
They require
trimming and
contouring

7. • 2- Pretrimmed ( prefestonned ) crown
Has straight sides
straight longer than the teeth
already trimmed to follow the gingival
contour
trimming is minimal but contouring is
required

8. • 3- Pre contoured crown
It is trimmed and also contoured
its margins curved inward
it is in the right length for the average tooth
in many cases it fits accurately with out
alteration

9. What you will need
u Burs and stones
– #169
– heatless stone
u Pliers and instruments
– contouring plier
– crimping plier
u Polishing

10. Steps for St St C
• Local anesthesia administration
• Rubber dam isolation
• Wooden wedge placement or T band
to avoid damaging the adjacent tooth
structure

11. Overview
u Occlusal reduction
u Proximal reduction
u Buccal and lingual
reduction
u Beveling
u Round all sharp line
angles and corners

12. Step by Step
u Caries removal
u Complete pulp therapy if necessary Proceed with
crown preparation
u Occlusal Reduction - 1.0-1.5mm
Connect the Depth Cuts
Check reduction with opposing arch

13. Proximal Reduction
u Contact with adjacent teeth must be broken
gingivally and buccolingually
u proximal slices converge slightly toward the
occlusal and lingual
– DO NOT OVER TAPER
u The gingival margins should have a feather-
edge finish line
u Adjacent tooth structure must not be damaged

14. Angulation of Slices
Proper slice Improper slice

15. Ledging
u Proximal slice must
be extended below
tissue to avoid
leaving a ledge

16. Preserving the Outline
u Remember: crown preparation if a significant part
of the crown’s retentive potential

17. Buccal-Lingual Reduction
u Reduction is optional and is undertaken only if
the buccal or lingual bulges are so prominent
that the constricted margin of the crown will not
go over he height of contour
– when required, no more than .5-1mm should
be removed
– reductions must end in a feather edge

18. Beveling
u A bevel at an angle of 30-45 degrees
removes the sharp cusp tips and creates a
gentle slope in the occlusal third of the
lingual and buccal surfaces

19. Round Sharp Line Angles
u The buccal and lingual
proximal line angles are
rounded by holding the bur
parallel to the tooth’s long
axis and blending the
surfaces togetherThe finished
contour should conform to
the internal contour of the
stainless steel crown

20. Crown Adaptation
u Mark gingival line with a scaler & trim 1mm
beneath the mark using C&B scissors Margins
should be trimmed to lie parallel with the contour
of the gingival tissue and consist of a series of
curves without sharp angles

21. Guidelines
u Resistance in seating without tissue blanching.
Check for
– high spots on occlusal surface
– ledges
u Resistance in seating with tissue blanching.
Check for
– crown too wide (preliminary contouring)
– crown too long
– tissue caught in margin

22. Gingival Contours
Buccal gingival contour of first
primary molar-- stretched-out S
Proximal gingival contour of
primary molars -- frown
Buccal gingival contour of second primary molar-- smile

23. Contour the Crown
u Use contouring pliers, bend the gingival third
of the crown’s margins inward to restore
anatomic margins and to reduce the marginal
circumference ensuring a good fit
u Crimp the crown
u With the crown-crimping plier (#118) crimp the
margin Replace crown on tooth and check margins
with an explorer

24. Crown Adaptation
Poor marginal seal may allow
micro leakage of bacteria and their toxic products leading
to recurrent decay or pulp inflammation.
• It may be necessary to remove the rubber dam at this
stage.
• Try the crown on the tooth.
• Seating the crown is from the less to more bulging
surface,
• e.g. from buccal to palatal in maxillary teeth, and from
lingual to buccal in mandibular teeth
• Evaluate the opposite arch for proper cusp and occlusal
interdigitaion.

25. • Marginal ridge are level with those of
adjacent teeth.
• Contacts are restored.
• No extensive blanching of the gingiva to
avoid trauma to the gingival tissue.

26. Finishing and Polishing
u Use heatless stone to smooth jagged edges
u Then use a rubber wheel to remove small
scratches and smooth
u Polish surface of crown to a high shine with
tripoli and rouge

27. The crown margins should have
• Smooth edges
• Edges free of burs
• Knife edge margins
• Smooth curved margins
• No riples or bend
• No scratches

28. Cementation
u Clean crown and tooth
u Fill crown with zinc phosphate cement
u Seat crown, expressing cement form all margins
and press into occlusion
u Remove excess cement when partially set

29. Crown cementation
• The following cements can be used
Polycarboxylate cement
advantages:
*minimal irritation effect on the pulp
*there is some adhesion between tooth
substance and st, st, alloys
Disadvantages:
*Require precise preparation and manipulation
*need clean and uncontaminated tooth surface

30. Glassionomer cement
• Advantages:
*Have the potential to adhere to tooth structure
*Fluoride release
• Disadvantages:
*Moisture sensitivity
* Initial slow set.
* Some pulp irritation.
Crown cementation

31. • Zinc phosphate cements:
• Because of its low pH
• lack of antibacterial properties.
• solubility in oral fluids
• lack of adhesion,
they are not recommended for cementation
of Stainless steel crown in primary molar.
Crown cementation

32. • Adhesive cements
• Advantage
Improve the retention
Reduce micro-leakage
• Disadvantages
They are more difficult to manipulate,
More technique sensitive and more
expensive than conventional cements.
Crown cementation

33. • Before cementation, a cavity varnish must
be applied on a vital tooth.
• Clean and dry the crown and the tooth
(partial isolation until setting of the
cement).
• Fill the crown with the cement while the
mix is glossy.
• Seat the crown firmly into occlusion,
• instruct the patient to bite on the seater to
ensure complete seating.
Crown cementation

34. • Remove excess cement with explorer on
labial and lingual and with loss
• Excess cement can produce gingival
inflammation and discomfort.
• Make a final check and follow-up.
Crown cementation

35. Post-op instructions ?
u Although a well-adapted and cemented
crown should not come off under these
circumstances, patients and parents
should be warned of the possibility

36. Some problems and their solutions
1-Crowns does not seat properly
• This usually means that there is a ledge. It is
removed using a tapered fissure bur.
u May need to increase the buccal and
lingual reductions
u May need to compress crown form on
mesial and distal with Howe pliers
•

37. Clinical Variations
u “Back-to-back”
chrome crowns
Second primary
molars

38. Possible solutions to this problem:
1-The crown is rotated slightly mesio-buccally so
that it is rotated slightly out of the arch.
2- The closest fitting crown is held in the beaks of
Adams pliers and squeezed mesio-distally to
reduce this dimension. This is an effective way
of flattening the contact points.
3- If difficulty is still encountered, additional tooth
reduction of the buccal and lingual surfaces and
selection of another smaller crown.

39. Placement of the adjacent crowns
• Tooth preparation and crown selection for
placing multiple crowns are similar to the
technique previously described for single
crowns, but with a few additional factors

40. • Prepare the occlusal reduction of one tooth
completely before beginning the occlusal
reduction of the other tooth. When reduction of
the two teeth is performed simultaneously, the
tendency is to under-reduce both.
• Insufficient proximal reduction is a common
problem. Contact between adjacent proximal
surfaces should be broken producing
approximately 1.5 mm space at the gingival
level.
Placement of the adjacent
crowns

41. • Crowns should be trimmed, contoured and
prepared for cementation
• It is generally best to begin placement and
cementation of the more distal crown first.
• The sequence of placement of crowns for
cementation should follow the same
sequence as that used when the crowns are
placed for the final fitting.
Placement of the adjacent
crowns

42. Restoration of Class IV Caries in
Primary Anterior Teeth
u Esthetic Resin Restoration
u Stainless Steel Crown
u Open-Face Steel Crowns
u Composite Crowns
Composite Crowns

43. Anterior Stainless Steel Crowns
u Esthetics - poor
u Durability - very good
u Time for placement - fastest
u Selection criteria - severely decayed, esthetics of
minimal importance, gingival hemorrhage not
controlled, inadequate patient cooperation

44. Open Faced Stainless Steel Crown
u Esthetics - okay
u Durability - good, although facing may be
dislodgedTime for placement - takes longest to
place due to two-step procedureSelection criteria
- severely decayed teeth, durabilty needed,
esthetics are a concern

45. Crown Form Selection
u Select the appropriate crown form size
from the mesio-distal measurement (mm)
of the tooth’s incisal edge, or by direct
comparison

46. Tooth Preparation
u Incisal reduction
– 1-1.25 mm
u Proximal reduction - parallel mesial and
distal slices to break contact with the
adjacent tooth and to allow enough bulk
to give strength to the final restoration
– .5-1 mm

47. Tooth Preparation
u Buccal reduction - to allow the placement of the
restoration within the normal buccal lingual
width of the tooth restored
– .5-1 mm
u Lingual reduction - to allow for the necessary
bulk for the strength of the crown and to
prevent for any occlusal interferences

48. Circumfrential Undercut Shoulder
u Terminates at the crest of the gingiva
u Shoulder depth should be .75-1 mm
u Use inverted cone

49. Variation
Cervical undercut on facial only
Removal of caries may also provide undercuts

50. Crown Adaptation
u Carefully trim off the cervical collar with
curved festooning scissorsTrim crown form
so that when seated, it covers the shoulder
but extends no more than 1 mm past tge
shoulder

51. Trial Fitting of Crown Form
u Try on trimmed crown formIncisal
edges should line upPlace hole in
incisal edge of crown with an explorer
to allow vent for composite to flow
through during crown placement

52. Crown Placement
u Etch tooth with phosphoric acid for 30 seconds
u Thoroughly wash and dry etched surface
u Apply bonding agent according to specifications
u Carefully pack the crown form resin to avoid
entrapment of air bubbles
u Position the filled crown form over the prepared
tooth so it extends 1mm over the gingival margin
u Remove excess resin from margins with an
explorer before polymerizing
u Slice crown form

53. Minimal Finishing and Polishing
u Peel it away from composite crown
u Finish margins
u Adjust occlusion
u DO NOT FINISH the labial surface
– polymerization of the resin against the
plastic provides the smoothest and most
stain resistant surface