pedogogy on ss crown

2. PRESENTED BY,
SINU JAYAPRAKASH
PG STUDENT
DEPT OF PEDIATRIC & PREVENTIVE
DENTISTRY
STAIN LESS STEEL CROWNS,

3. CONTENTS
.INTRODUCTION
.DEFINITION
.CLASSIFICATION
.Indications and contra indication
armamentarium
.modification
.Clinical procedure
.CONCLUSION
.REFERENCES

4. INTRODUCTION
In the last half century ,the emphasis on treatment of extensively decayed
primary teeth ( common pediatric dental problems ) shifted from
extraction to restoration .
Although ssc has ben used since 30 years very less significant research
was done in this field.

5. STAIN LESS STEEL CROWNS
ROCKY MOUNTAIN
COMPANY
1947
INTRODUCED TO PEDIATRIC
DENTISTRY BY
HUMPHREY & ENGEL
1950
1968-Mink and Bennett –initial crown
preparation
1960s - significantly improved
crown (Unitek) 5

6. DEFINITION
Stainless steel crowns can be defined as the
prefabricated crown forms that are adapted to the
individual teeth and cemented with a biocompatible
luting material

7. ACCORDING TO TRIMMING
UNTRIMMED
CROWNS
Not trimmed
not contoured
require lot of
adaptation ,
time consuming.
Eg.THE ROCKY
MOUNTAINS
PRETRIMMED
CROWNS
straight,non -
contoured sides
festooned
Eg,Unitek ,3M
Co. and Denovo
crowns
PRECONTOURED
CROWNS
festooned
precontoured
though a minimal
amount of
festooning and
trimming may be
necessary .
Eg,Ni-Chro Ion
crowns,Unitek
stainless steel
crowns,3M Co.

8. ACCORDING TO
COMPOSITION
STAIN LESS STEEL
CROWNS -18-8 austenitic
stainless steel (67%
fe,18%cr,8% ni)
NICKEL-CHROMIUM
CROWNS –Nickel chrome
alloy(70%ni,15%cr,10%fe)
ACCORDING TO
POSITION
CROWNS FOR
POSTERIOR TEETH
CROWNS FOR
ANTERIOR TEETH

9. ACCORDING TO
COMPANY
ACCORDING TO
OCCLUSAL ANATOMY
The Rocky Mountains
Unitek
3M
Iconel
Nusmile
Ion –compact occlusal
anatomy
Unitek –best occlusal
anatomy
Rocky Mountains –
occlusally small
Ormco-smallest & least
occlusally carved.

10. RESTORATION OF PRIMARY &
YOUNG PERMANENT TEETH WITH
EXTENSIVE CARIOUS TEETH
RESTORATION OF HYPOPLASTIC
PRIMARY & PERMANENT TEETH
RESTORATION OF PRIMARY TEETH
FOLLOWING PULPOTOMY OR
PULPECTOMY PROCEDURES
INDICATIONS

11. RESTORATION OF TEETH WITH HEREDITARY
ANOMALIES SUCH AS –DENTINOGENESIS
IMPERFECTA ,AMELOGENESIS IMPERFECTA
RESTORATIONS IN DISABLED INDIVIDUALS
OR OTHERS IN WHOM ORAL HYGIENE IS
EXTREMELY POOR AND FAILURE OF OTHER
MATERIALS IS LIKELY
AS AN ABUTMENT FOR SPACE MAINTAINERS
OR PROSTHETIC APPLIANCES

12. 1. Close to exfoliation
2. Clinical or radiographical evidence of radicular pathology
3. Excessive mobility
4. nickel allergy or sensitivity
5. Partially erupted teeth
6. Esthetically unappealing
7. Where conservative restorations can be placed
8. More than half the roots resorbed
CONTRAINDICATIONS

13. ARMAMENTARIUM
Burs and stones
Burs no 169L or no 69L
Tapered diamond
Green stone or heatless stone
Rubber wheel

14. Pliers/instruments
Ball-and-socket plier { #112} or Johnson’s Contouring pliers{# 114 /
# 134}
Crown crimping plier {# 800-417}
Howe plier { #110 }
Crown remover
Crown scissors

15. CLINICAL PROCEDURE
A) Evaluate pre-operative occlusion
B) Administer LA
C) Place rubber dam
D) Crown selection
E) Tooth preparation
F) Evaluation of tooth preparation
G) Crown adaptation
H) Crown finishing & polishing
I) Crown cementation
J) Post operative instructions

16. 1.PRE-OPERATIVE EVALUATION
Diagnostic casts
Midline
Cusp fossa relationship bilaterally
Canine relation
Extrusion of opposing tooth
2.LA ADMINISTRATION
To reduce the discomfort during subgingival preparation
3.RUBBER DAM PLACEMENT
Protect surrounding tissues
Visibility
Improve efficiency

17. 4.CROWN SELECTION
3 main considerations :
Mesiodistal diameter
Light resistance to seating
Proper occlusal height
Before preparation : Boley gauge
After preparation : trial & error
Smallest crown selected
Friction to be felt when crown slips gingivally

18. TOOTH PREPARATION
Aim of tooth preparation :
To provide sufficient space for SSC
To remove complete caries
To have sufficient tooth for retention of crown
OCCLUSAL REDUCTION
* Humphery 1950 • All sides reduced • Retain crown structure
* Rapp 1966 • Occlusal reduction to keep atleast 4 mm from gingival
margin
* Mink & Bennett 1968 • Uniform occlusal reduction 1- 1.5 mm •
*Troutman . 1mm
*Kennedy. 1.5 to 2mm

19. Evaluation of occlusal reduction
Forrester 1981 : Wax sheet
Visual examination
Mathewson : Use of explorer

20. PROXIMAL REDUCTION
Wooden wedge inter proximally
69L or 169L bur moved buccolingually
Begin at the marginal ridge & hold the bur slightly at an angle to the long
axis of tooth and extend the slice to buccal & lingual line angles giving 2-5
degree taper

21. Do not overtaper
Feather edge finish line-without any shoulder or ledge.

22. BUCCAL & LINGUAL REDUCTION
Natural undercuts : retention
Mathewson 1974, Andlow & Rock 1984, Mink & Bennet 1968:
Large buccal bulge : buccal reduction required
no reducation required :Pinkham

23. CROWN ADAPTATION
Try crown on tooth : lingual to buccal
Mark scratch line
Cut 1 mm below it with scissors
Place the crown again :
If blanching seen : rescribe & retrim
If doesn’t seat completely : reduce occlusal surface

24. CROWN CONTOURING
Gingival Contours
Buccal gingival contour of E : Smile
Buccal gingival contour of D : Stretch out ‘S’
Proximal contour of primary molars : Frown
Lingual contours of all molars : Smile
Contouring pliers used :
# 112 Ball & Socket Plier
#137 Gordan plier
# 114 Johnson plier
Used for initial contouring in middle third : Belling effect

25. CROWN CRIMPING
Inward movement of margins
Crown crimping plier No.417
After crimping
Snap into position with firm finger pressure
Mechanical retention
Protection of cement from
exposure to oral fluids
Maintenance of gingival health

26. FINAL TRIAL
Resistance in seating without blanching
Check for ledges
Resistance to seating with blanching
CROWN FINISHING & POLISHING
Unpolished : plaque & gingivitis
Large green stone : Knife edge finish cervically
Rubber wheel : to smoothen the margins
Wire brush : to polish entire crown
Rouge : to give fine lusture

27. CROWN CEMENTATION
Crown & tooth has to be cleaned
Vital tooth : cavity varnish {Meyers 1983}
Cements :
ZnOE
Polycarboxylate
ZnPO4
GIC
Reinforced ZOE
Silicophosphate
Most commonly used : GIC

28. CROWN CEMENTATION
1. Place 2 X 2” gauze posteriorly to tooth
2.Tooth & crown cleaned
3. Isolation mandatory
4. Apply vaseline to contact areas
5. Mix luting cement till 1 ½” strings are formed
6. Place the cement in crown to fill approx 2/3rd
7. All inner surfaces covered with cement
8.Seat crown from lingual to buccal
9.Cement should be expressed out from sides
10. Ask to chew in centric occlusion
11. Excess cement removed with scaler or explorer
12. Floss moved buccolingually
13. Support the mandible during the procedure

29. CLINICAL MODIFICATIONS
Adjacent S.S.C
Adjacent S.S.C with amalgam restoration
Adjacent S.S.C with arch length loss
Undersized tooth / oversized crown
Oversized tooth / Undersized crown
Deep subgingival caries
Open contacts

30. UNDERSIZED TOOTH/OVERSIZED CROWN (MINK & HILL,1971)
Due to longstanding mesial & distal caries
1.V cut made on buccal surface
from gingival to occlusal surface
2.Cut edges reapproximated
to overlap one another
3.Crown tried on tooth & amount
of overlap necessary marked
4. Overlapped edges spot welded

31. DEEP SUBGINGIVAL CARIES
ROUTINE
CROWN
PREPARATION
BANDS
AMALGAM/GIC
RESTORATION
SUBSTITUTE THE
TOOTH
STRUCTURE
SOLDER AN
EXTENSION ON
INTERPROXIMAL
AREA OF CROWN

32. CAUSES OF S.S.C FAILURES
Inadequate tooth reduction
Inadequate crown contouring & crimping
Inappropriate established occlusion
Inappropriate cementation
Pulp treatment failure
Recurrent caries : improper contact
Crown abrasion : occlusal surface

33. COMMON ERRORS
Lack of feather edge
Failure to round all line angles
Incorrect crown size
Excessive reduction of tooth
Ledges formation