The given slides are for the brief description of the topic stainless steel crowns used in pediatric dentistry

1. STAINLESS STEEL CROWN IN
PEDIATRIC DENTISTRY
PRESENTED BY: RAJAT HEGDE

2. CONTENT
• History
• Composition
• Classification
• Indications
• Contraindications
• Pre-operative evaluation
• Clinical procedure
• Special considerations
• Complications
• Reference

3. HISTORY
• Introduced by Humphrey in 1950s as chrome steel crown.
• It significantly improved in 1960s (UNITEK).
• SSC is a semi-permanent restoration used in primary and young
permanent molar.
• Semi-permanent restorations were introduced due to extensive
failure of class II restorations in primary molars, and class III,
IV in primary anterior teeth.

4. COMPOSITION
Nickel Base Crowns
72% nickel
14% chromium
6-10% iron
0.35% manganese
0.2% silicon
Trace amounts of carbon
Stainless Steel Crowns
67% iron
17-19 % chromium
10-13% nickel
4% minor elements

5. CLASSIFICATION
I. Based on Composition :
1) Stainless steel crowns – Unitek and Rocky mountain crown.
2) Nickel-base crowns
3) Tin-base crowns
4) Aluminium crowns

6. II. Based on Morphology:
1) Uncontoured / Untrimmed crowns
• Neither trimmed nor contoured.
• Requires lot of adaptation.
• Time consuming.
• Eg: Rocky mountain crown

7. 2) Pretrimmed Crowns :
• Have straight non-contoured sides.
• Shorter and festooned.
• Require contouring and trimming.
• Eg : Unitek SSC, Denvo crown
3) Precontoured Crowns :
• Precontoured, pretrimmed, festooned.
• Trimming is minimal.
• Eg: Unitek SSC, Ni-Cr Ion crown

8. INDICATIONS
• Extensive caries in primary molars and young permanent molars.
• Caries involving more than 2 surfaces.
• Hypoplastic defects such as molar incisor hypo-mineralization
(MIH).
• Following pulp therapy .
• Teeth with developmental anomalies – enamel hypoplasia,
dentinogenesis imperfecta.
• As an abutment for certain appliances such as space maintainers.

9. CONTRAINDICATIONS
• If the primary molar is close to exfoliation and more than half of
the roots are resorbed.
• Any radicular pathology.
• Partially erupted teeth.
• Tooth exhibiting excessive mobility.
• Patients allergic to nickel.

10. PRE-OPERATIVE EVALUATION
1) Dental Age of the Patient :
• It’s recorded by root development of the underlying tooth.
• Amalgam and GIC is chosen if the tooth is expected to exfoliate within
2 yrs.
2) Patient Cooperation :
• Patient may show negative behavior or under aged (<3 yrs).
• GA or sedation is considered.
• Operator needs to check the occlusion before treatment.

11. 3) Parent Motivation :
• Sometimes parents are worried about dislodegement or
discoloration of fillings.
• Enough explanation and confidence need to be given to them.
4) Medically Compromised / Disabled Children :
• Patient with cardiac problem need more precise margin adaptation
to prevent gingival inflammation.
• GA or sedation has to be considered for disabled patient.

12. CLINICAL PROCEDURE
Includes the following steps:
1. Evaluation of pre-
operative occlusion.
2. Crown selection.
3. LA administration.
4. Rubber dam placement.
5. Tooth preparation.
6. Try-in of crown
7. Crown contouring
8. Trimming and crimping
9. Finishing and polishing.
10. Filling the cavity and seating
the crown.
11. Removal of excess cement
and occlusal check.
12. Final adaptation of the
crown.
13. Radiographic evaluation
14. Post-operative instructions.

13. EVALUATION OF PRE-OPERATIVE OCCLUSION :
• Occlusion is evaluated by taking impression and making cast.
• If it’s not possible to make a cast, then careful examination of occlusion
is done before giving LA and rubber dam placement.
CROWN SELECTION :
• Before tooth preparation : by measuring mesio-distal dimension with
Boley gauge.
• After preparation : by trial and error procedure.
• The smallest crown that completely covers the preparation should be
chosen.
• Crown should have tight snap fit – resistance should be there when
crown slips gingivally.

14. TOOTH PREPARATION :
Aim -
• To provide sufficient space for SSC.
• To leave sufficient tooth for crown retention.
• To remove caries.
Occlusal Reduction :
• Occlusal surface is reduced by about 1.5-2 mm to obtain occlusal
clearance.
• #330 bur (cutting part - 1.5mm) is used for giving guiding groove of
about 1 – 1.5 mm depth following cuspal outline.
• Care should be taken not to expose the pulp, especially lower 1st primary
molar, as mesial pulp horn is relatively high just below intercuspal ridge.

15. Proximal Reduction :
• #102 diamond bur is moved vertically in a sawing action to cut off
the proximal area.
• The width clearance between teeth should be atleast 1mm at the
gingival level.
• Care should be taken to not cut adjacent tooth.
• A wedge can be used in interproximal embrasure.
• Ledges are avoided as they pose difficulty in seating the crown.

16. Buccal and Lingual Reduction :
• It’s minimal.
• Usually done on 1st primary molar having big buccal bulge.
Roundening the Line Angles :
• Occluso-buccal and occluso-lingual line angles are rounded off.
• The bur is held at 30-45° angle to occlusal surface and is moved in
mesio-distal direction.

17. TRY-IN OF CROWN:
• For upper tooth, seat the buccal first and snap to palatal.
• For lower molars, seat lingual first and snap to buccal.
• Resistance should be felt as the crown slips over the tooth bulge.
• Margin should be in gingival sulcus.
• The crown should not compress and produce blanching of marginal
gingival tissue.

18. CROWN CONTOURING :
• Used for initial contouring of middle 1/3rd of crown to
produce belling effect.
• It’s done using crown contouring pliers.
• Shape of gingival contours:
1) Buccal gingival contour – ‘Stretchout – S’ for 1st molar,
‘Smile’for 2nd molar.
2) Proximal contour – Frown
3) Lingual contour – Smile

19. TRIMMING AND CRIMPING :
• It’s done if the crown is impinging the gingival sulcus.
• Crown scissor or green stone is used to trim.
• Crimping is the procedure of compressing or giving
inward bend of crown margin for tight marginal fit.
• Its done using crown crimping plier.

20. FINISHING AND POLISHING :
• Unpolished restoration causes accumulation of plaque and inflammation
of gingiva.
• Hence, crown is polished prior to cementation with a rubber wheel to
remove all scratches.
• A wire brush ca be used to polish the margins to a high shine.
• A fine polishing material like rouge is used to give fine lustre to crown.

21. FILLING THE CAVITY AND SEATING THE CROWN :
• Tooth and crown is cleaned.
• Isolation of teeth is done using cotton rolls.
• Zinc phosphate, polycarboxylate or GIC is preferred for luting.
• Vaseline is applied to contact areas.
• Luting cement is mixed till strings are formed.
• The cement is placed filling approximately 2/3 rd of crown with all inner
surface covered.

22. • The crown is seated from lingual to buccal.
• Excess cement should be expressed out from sides.
• Patient is asked to bite in centric occlusion.
• Excess cement is removed using scaler and explorer.
• Floss is moved buccolingually.

23. REMOVAL OF EXCESS CEMENT AND OCCLUSAL CHECK :
• Rubber dam is removed and patient is asked to bite.
• Excess cement is removed.
• A knot in floss is made and passed in the interproxial area.

24. FINAL ADAPATION OF THE CROWN :
• The crown must snap into place.
• It should fit so tightly that there is no rocking on the tooth.
• A properly seated crown will correspond to the marginal ridge height of
the adjacent tooth.
• There should not be any high points when checked using articulator.
• The crown margin closely adapts and extends about 1mm into gingival
sulcus.
• The restoration should enable the patient to maintain oral hygiene.

25. RADIOGRAPHIC EVALUATION :
• A bitewing is taken to verify proximal marginal integrity.
• Crown margin should be adapted to proximal surface.
• They should not be too long.
POST-OPERATIVE INSTRUCTION :
Following should be avoided at least for an hour:
• Sticky foods – toffees, caramel
• Hard candies
• Popcorn kernels

26. SPECIAL CONSIDERATIONS FOR SSC
• These are the modifications reported by Mink and Hill (in 1971), when the
crown is either too large or too small.
UNDERSIZED TOOTH / OVERSIZED CROWN :
• Cause - long standing interproximal caries causing space loss.
• A cut is made on the buccal surface and the cut edges are re-
approximated to overlap one another.
• Thus, the crown circumference is reduced.
• After try-in the overlapped edges are spot welded and polished.

27. OVERSIZED TEETH / UNDERSIZED CROWN :
• The edges are separated as needed and a piece of
orthodontic band is welded.
• After contouring, the solder is applied to fill any
microscopic deficiency.
• The soldered crown is then polished.
DEEP SUBGINGIVAL CARIES :
• One approach is to complete the indicated pulp
treatment and then restore the cavity with amalgam.
• Another method is to solder an extension on
interproximal areas of the crown.

28. COMPLICATIONS
INTERPROXIMAL LEDGE :
• It’s produced if the angulation of the tapered fissure bur is incorrect.
• Failure to remove this ledge will result in difficulty in seating the crown.
CROWN TILT :
• It’s due improper use of cutting instruments on buccal or lingual wall.
• The crown tilts towards the deficient side.
• Clinical significance is minimal unless it occurs on young permanent
molars where supra-eruption of opposing teeth may occur.

29. POOR MARGINS :
• Marginal integrity is reduced when the crown is poorly adapted.
• Recurrent caries may occur around open margins.
• Chances of plaque retention and gingivitis increases.
INHALATION / INGESTION OF CROWN :
• It may result due to sudden movement.
• Rubber dam must be placed to prevent such mishaps.
• If this occurs, an attempt can be made by holding the child upside down
as soon as possible.
• If it’s unsuccessful, medical referral should be done for an immediate
chest x-ray.

30. REFERENCE
• Shobha Tandon (3rd Edition).

31. THANK YOU