stainless steel crown in pediatric dentistry, effect of sandblasting ,groove placement, cement type on retention of stainless steel crown

2. The Effect Of retentive groove,sandblasting & cement type
on retentive strength of Stainless Steel crowns in primary
second molars – An invitro comparative study
- Veerabadhran et al
J Indian Soc Pedod Prev Dent 2012;30:19-26

3. INDEX
WHAT ARE STAINLESS STEEL CROWNS?
INDICATIONS
SS CROWNS Vs. MULTISURFACE RESTORATION
FABRICATION OF SS CROWN
SS CROWN MODIFICATION
AIMS & OBJECTIVES OF THE STUDY
MATERIALS & METHODS
RESULTS
DISCUSSION
HIGHLIGHTS OF THE STUDY
CONCLUSIONS

5. Stainless steel (preformed) crowns are
prefabricated crown forms which can be adapted to
individual primary molars and cemented in place to
provide a definitive restoration
American Academy of Pediatric Dentistry; Guideline on Pediatric Reestorative Dentistry
2012;35:226-234

6. CLASSIFICATION
• BASED ON COMPOSITION
1.
2.
3.
4.
STAINLESSS STEEL CROWN (UNITEK & ROCKY MOUNTAIN CROWNS)
NICKEL BASE CROWNS (ION Ni-chro FROM 3M)
TIN BASED CROWNS (Iso-form type)
ALUMINIUM BASE CROWNS (Gold anodised )

7. COMPOSITION
18-8 CROWNS
AUSTENITIC TYPE
• Chromium- 17-19%
• Nickel – 10-13%
• Iron-67%
• Minor elements-4%
NICKEL BASE
CROWNS
• Nickel-72%
• Chromium-14%
• Iron-6-10%
• Carbon-0.04%
• Manganese-0.35%
• Silicon-0.2%

8. • BASED ON MORPHOLOGY
1. UNCONTOURED/ UNTRIMMED CROWNS (ROCKY
MOUNTAIN)
2. PRETRIMMED CROWNS (UNITEK STAINLESS STEEL
CROWNS,3M,DE NOVO CROWNS)
3. PRECONTOURED CROWNS (Ni-chro ion crowns & Unitek 3M)

9. PREVEENERED
CROWNS
• Resin based composite bonded to occlusal
& buccal surfaces
• Allows minimal crimping
• Aesthetic

10. Availability
Crown Shape
Number of sizes
available
Width range mm
Upper 1st primary
molars
6
7.2 to 9.2
Upper 2nd primary
molars
6
9.2 to 11.2
Lower 1st primary
molars
6
7.3 to 9.3
Lower 2nd primary
molars
6
9.4 to 11.4
• Sizes 4 & 5 most often used
• Supplied in kit form with user needing to reorder
only those sizes frequently used

11. 3MTM ESPETM UNITEKTM
Stainless steel crowns
CROWN SHAPE
NUMBER OF SIZES
AVAILABLE
WIDTH RANGE
mm
Central/Lateral
12
4.2 to 8.0
Upper Cuspids
6
6.2 to 8.2
Lower Cuspids
6
4.8 to 6.8
Upper 1st primary molar
7
6.6 to 9.0
Upper 2nd primary molar 7
8.5 to 11.0
Lower 1st primary molar
6.9 to 9.3
7
Lower 2nd primary molar 7
8.5 to 11.5

12. INDICATIONS
• Carious primary molars where more than two
surfaces are affected/where one or two
surface carious lesions are extensive.
• Following pulpotomy or pulpectomy
procedures
• Primary molars affected by localized or
generalized developmental problems
• Fractured primary molars
• Patients with high caries succeptibility
Ray Stewart, Thomas Barber, Kenneth Troutman, Stephen Wei.Pediatric Dentistry- Scientific
Foundations & Clinical Practice St Louis : Mosby;1982

13. • As an abutment for certain appliances,
such as space maintainers.
• In patients where routine oral hygiene
measures are impaired.
• In patients undergoing restorative care
under general anaesthesia if two or more
surfaces are involved.
• In patients with infra-occluded primary
molars to maintain mesiodistal space.
Ray Stewart, Thomas Barber, Kenneth Troutman, Stephen Wei.Pediatric Dentistry- Scientific
Foundations & Clinical Practice St Louis : Mosby;1982

14. SSCROWNS Vs MULTISURFACE
RESTORATIONS
• stainless steel crowns have markedly
superior longevity when compared with
multi-surface amalgam restorations
• stainless steel crowns out-perform glass
ionomer cements and composite
restorations as well

15. ARMAMANTARIUM
• CROWN CUTTING BURS- pear shaped, tapered
fissured,finishing burs
• PLIERS – Hoe pliers(#110),Johnson’s contouring
plier#114,Ball & socket plier#112,Crimping
pliers#417,Gordon plier #137,crown scissors
• Scaler or any sharp instrument
• Stone & Finishing burs for crown finishing
• For cementation- luting cement,spatula,glass
slab
• Miscellaneous

18. FABRICATION OF STAINLESS STEEL
CROWNS
• PREOERATIVE STEPS : 1.Occlusal evaluation
2.Crown Selection
• OPERATIVE STEPS

19. OCCLUSAL EVALUATION
•
•
•
•
•
•
DIAGNOSTIC CAST
MIDLINE
CUSP-FOSSA RELATION
CANINE RELATION
EXTRUSION OF OPPOSING TOOTH
MESIAL DRIFTING

20. CROWN SELECTION
• MESIO DISTAL DIAMETER
• LIGHT RESISTANCE TO SEATING
• PROPER OCCLUSAL HEIGHT

21. CROWN SELECTION
• Before Preparation : Vernier Caliper
• After preparation : trial & error
• Smallest crown selected (No.4 & No.5
commonly)
• Friction to be felt when crown slips gingivally

22. • Crown should have :
1. Tight snap fit
2.Restore original contour & occlusal anatomy
3. Choose smallest crown that fits well

23. • THREE MAIN CONSIDERATIONS
A) Adequate M-D width
B) Crown: larger : tooth to be adapted
C) Too large crown will rotate on the tooth

24. OPERATIVE STEPS

25. TOOTH PREPARATION
INITIAL ADAPTATION OF CROWN
SEATING OF CROWN
CROWN CONTOURING
CROWN CRIMPING
FINAL ADAPTATION OF THE CROWN
FINISHING , POLISHING & CEMENTATION OF CROWN

26. TOOTH PREPARATION
• AIM
To provide sufficient space for SSC
To remove carious tooth structure
To have sufficient tooth structure for retention

27. TOOTH PREPARATION
Isolation
Removal of Decay
Crown Reduction : Occlusal Reduction
Proximal Slicing
Buccolingual Reduction
Round Off all the Line angles

28. OCCLUSAL REDUCTION
Humphery
1950
• All sides
reduced
• Retain crown
structure
Rapp 1966
• Occlusal
reduction to
keep atleast
4mm from
gingival
margin
Mink &
Bennett 1968
• Uniform
occlusal
reduction 11.5mm
• Troutman &
Kennedy
support it

29. • Occlusal reduction

30. • Occlusal anatomy preservation

32. PROXIMAL REDUCTION
• Wooden wedge interproximally
• 69L/169L bur moved buccolingually
• Begin at the marginal ridge & at 10◦
converging towards occclusal surface
• Feather edge finish line
• Pass explorer through proximal areas for
evaluation

33. • Proximal reduction

35. ANGULATION OF SLICES
PROPER SLICE
IMPROPER SLICE

36. No ledge should form just a
feather edge finish line
•Rounding up of line angles

37. Proximal reduction
Proximal box must be extended below the
gingival crest to avoid leaving a ledge
Ledge may cause :
 Obstructed crown placement
 Propping out of crown
 Stress area

38. BUCCAAL & LINGUAL REDUCTION
• Natural Undercuts : retention
• Mathewson 1974 Andlow & Rock 1984 Mink &
Bennet 1968 – Large buccal bulge : buccal
reduction required
• Pinkham : Large mesiobuccal
bulge ,both buccal & lingual
reduction required

39. EVALUATION OF TOOTH PREPARATION
• Explorer can be placed between the prepared
tooth & proximal tooth
• Occlusal clearance 1-2mm
• Buccal & lingual surface converge slightly
towards the occlusal if required then only
reduced 0.5mm with feather edge margin

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

41. GINGIVAL CONTOURS OF CROWN

43. CROWN CONTOURING
•
•
•
•
Contouring pliers :
Ball & socket plier # 112
Gordan plier #137
Johnson plier #114

44. • Contouring: the middle 1/3rd of the
crown (Belling effect)

45. CROWN CRIMPING
• Crimping:the gingival 1/3rd
of the crown margin

46. • Seating of the crown:
lingual to buccal
“click” sound for a snap fit

47. • Evaluation :
• Check with explorer :
If margins open : recrimp
If overextended : start again
Blanching : Johnson 1987
Bitewing radiograph : More & Pink 1973

48. FINISHING & POLISHING

49. CROWN CEMENTATION

50. SS CROWN MODIFICATIONS
•
•
•
•
•
Undersized tooth / Oversized crown
Oversized tooth / Undersized crown
Deep subgingival caries
Open faced SS Crowns
Open Contact

51. UNDERSIZED TOOTH/ OVERSIZED
CROWN(Mink & Hill 1971)
Occur due to long standing nature of caries
V-cut made on
the buccal
surface from
gingival to
occlusal
surface
Cut edges
reapproximate
d to overlap
one another
Crown tried
on tooth &
amount of
overlap
marked
Overlaped
edges spot
welded

52. OVERSIZED TOOTH & UNDERSIZED
CROWN
Try the crown on the
tooth
Cut V on buccal or
lingual side as needed
Again try the crown
on tooth
Place ortho band and
spot weld it

53. DEEP SUBGINGIVAL CARIES
Routine
crown
preparation
• Amalgam/GIC
restoration
substitute the tooth
structure
Band
• Solder an extension
on interproximal
area of crown

54. OPEN CONTACT
• Leads to food packing,plaque retention &
gingivitis
• Large crown selected
• Interproximal contour exagerated with #112
plier
• Or addition of solder inter proximally

55. OPEN FACED SS CROWNS
Cut window in the crown which is
• Just short of incisal edge
• Gingivally till the height of gingival crest
• Mesiodistally till line angles

56. OPEN FACED SS CROWN
•
•
•
•
•
•
Composite Material on labial fenestration
Time consuming
Metal margins still visible
Difficult to control hemorrhage
Increased chair side time
Gradual deterioration in appearance

57. THE STUDY…..

58. AIMS & OBJECTIVES
• Effect of retentive Groove placement on retention
of SS Crown
• Influence of cement type on Retentive strength
• Efficacy of sandblasting of the crown on Crown
retention
• Retention of SSC on Maxillary primary 2nd Molar
Vs that on Mandibular Primary 2nd Molar
• Interation of any two factors mentioned above

59. MATERIALS & METHODS
• Developing the experimental design matrix
• Conducting the experiment as per design
matrix
• Recording the Results i.e Retentive Strength

60. THE DESIGN MATRIX

61. THE EXPERIMENT
• Specimen: Total 16 extracted intact human
primary maxillary and mandibular second
molars(8 each) were mounted in
Autopolymerising Resin
• Pretrimmed Precontoured SS Crowns were
selected
• Tooth Preparation done
• Crown Adaptation done

62. • Weldable buccal tubes welded on buccal &
Lingual surface of all crowns
• Groove placement done on indicated teeth
• Sandblasting of indicated crowns done with
AlOxide particles of size 250μm
• GIC (GC Fuji I) or RMGIC(FujiCemTM )

63. RECORDING THE RESULTS
• Universal Testing Machine (Unitek94100
FIE,India)
• Retentive Strength = load / Area (kg/cm2)
• Data was analysed using ANOVA
• t-test was done for pairwise comparison
• SPSS statistical package was used

64. RESULTS….

67. DISCUSSION
• Mitchell et al had put forth that RMGIC offered
higher retention as compared with GIC
• Garcia-Godoy for the first time roughened the
interior of the crown with high speed bur to
create more retentive surface
• O’Connor et al discovered that microblasting the
internal surface of cast crowns with 50μm AlO2
improved the retention of castings luted with Zinc
Phosphate
1.Mitchell CA, OrrJF, Connor KN, Magill JP, Maguire GR. Comparative study of four Glass ionomer luting cements during post
pull-out tests.Dent Mater 1994;10:88-91
2.Garcia-Godoy F.Clinical evaluation of the retention of preformed crowns using two dental cements J Pedod 1984;8:278-81
3.O’Connor RP, Nayyar A, Kovarik RE. Effect of internal microblasting on retention of cemented cast crowns.J Prosthet Dent
1990;64:557-62

68. • Worley et al on the other hand observed that
sandblasting of crown had no significant effect on
retention
• Rosensteil et al had stated that Adding grooves /
boxes to a preparation with a limited path of
withdrawl doesn’t affect its retention
• Retentive grooves are generally placed proximally
which significantly increase the retention of the
cast crown
• Potts et al had contradicted this notion in their
study
1.Worley JL, Hamm RC, von Faunhofer JA. Effects of cement on crown restoration.J Prosthet Dent 1982;48:289-91
2.Rosensteil SF, Land MF, Fujimoto J. Contemporary Fixed Prosthodontics. 3rd ed. St Louis: Mosby; 2001
3.Saad AA, Claffey N, Bryne D, Hussey D. Effect of groove placement on retention/resistance of maxillary anterior resin bonded retainers. J Prosthet Dent 1995;74:133-9
4.Pal V, Shetty V, Joseph M. Comparitive evaluation of auxillary retentive feactures on retention of complete cast crowns in teeth with adequate and inadequate crown
height-an in vitro study. Indian J Dent Res 1999;10:5-10

69. • Yilmaz et al found out that resin cement
significantly improved crown retention when
compared against RMGIC. However, the
difference was not significant when compared
against GIC.
Yilmaz Y, Dalmis A,GurbuzT,Simsek S;Retentive Force and Microleakage of Stainless
Steel Crowns Cemented with Three Different Luting Agents; Dental Materials Journal
23(4): 577-584, 2004

70. HIGHLIGHTS OF THE STUDY
• Pairwise comparision of two factor interactions
• Only three combinations were statistically
significant viz 1.Groove & Cement
2.Groove & Sandblasting
3.Cement type & molar
• In absence of groove RMGIC offers better
retention than GIC
• Crowns which were not sandblasted offered
better retention when grooves were not given.

71. CONCLUSION
• RMGIC can be recommended for the
cementation of Stainless Steel Crowns for
better retention
• Grooves do not add to the retentive strength
of the crowns so they can be avoided in tooth
preparation of primary teeth

72. REFERENCES
1.Randall RC, Vrijhoef MMA, Wilson NHF. Efficacy of preformed metal crowns
vs.amalgam restorations in primary molars: a systematic review. Journal of the
American Dental Association 2000; 131:337-343.
2.Randall RC. Preformed metal crowns for primary and permanent molar teeth:
review of the literature. Pediatric Dentistry 2002; 24(5):489-500
3.Braff MH. A comparison between stainless steel crowns and multisurface
restorations in primary molars. Journal of Dentistry for Children 1975; 42: 474-8
4. Dawson LT, Simon JR, Taylor PP. The use of amalgam and stainless steel
crown restorations for primary molars. Journal of Dentistry for Children 1981;
48: 420-2
5. Messer LB, Levering NJ. The durability of primary molar restorations:
Observations and predictions of success of stainless steel crowns. Pediatric
Dentistry 1988; 10(2):81-85.
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73. 7.Papathanasiou AG, Curzon ME, Fairpo CG. The influence of restorative
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8.O’Sullivan EA, Curzon MEJ. The efficacy of comprehensive dental care for
children under general anaesthesia. British Dental Journal 1991;171:56-58.
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10.Mitchell CA, OrrJF, Connor KN, Magill JP, Maguire GR. Comparative study
of four Glass ionomer luting cements during post pull-out tests.Dent Mater
1994;10:88-91
11.Garcia-Godoy F.Clinical evaluation of the retention of preformed crowns
using two dental cements J Pedod 1984;8:278-81
12.O’Connor RP, Nayyar A, Kovarik RE. Effect of internal microblasting on
retention of cemented cast crowns.J Prosthet Dent 1990;64:557-62

74. 13.Worley JL, Hamm RC, von Faunhofer JA. Effects of cement on crown restoration.J
Prosthet Dent 1982;48:289-91
14.Rosensteil SF, Land MF, Fujimoto J. Contemporary Fixed Prosthodontics. 3rd ed. St
Louis: Mosby; 2001
15.Saad AA, Claffey N, Bryne D, Hussey D. Effect of groove placement on
retention/resistance of maxillary anterior resin bonded retainers. J Prosthet Dent
1995;74:133-9
16.Pal V, Shetty V, Joseph M. Comparitive evaluation of auxillary retentive feactures on
retention of complete cast crowns in teeth with adequate and inadequate crown
height-an in vitro study. Indian J Dent Res 1999;10:5-10
17.Potts RG, Shillingburg HT, Duncanson MG Jr. Retention and resistance of
preparations for cast restorations. J Prosthet Dent 1980;43:303.
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