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A . Mahesh kumar
Pg 1st year student
Dept of pedodontics &
preventive dentistry
Dr s&n sids
Contents
 INTRODUCTION
 HISTORY
 OBJECTIVES
 INDICATIONS OF STAINLESS STEEL CROWN
 FACTORS TO BE CONSIDERED IN PRE-OP...
contents
 ARMAMENTARIUM FOR SS CROWN
RESTORATIONS
 CLINICAL PROCEDURE
 TOOTH PREPARION
 CROWN PREPARATION
 MODIFICATI...
REFERENCES
 Kennedy’s Pediatric Operative Dentistry_ Curzon, kennedy
DB, Roberts
 Pediatric dentistry total patient care...
 M memarpour ,D Reza M Razavi Comparison of
microleakage from stainless steel crowns margins used
with different restorat...
INTRODUCTION
 The preformed metal crown (PMC), more commonly
known as the Stainless steel crown (SSC) has been used
for a...
History
 1950: The first preformed crowns marketed
 1960: Significantly improved crown festooned margins
to correspond t...
Objectives
 The objectives of stainless steel crown restoration are:
 1) To achieve biologically compatible masticatory
...
Indications for ssc
 After pulpotomy or pulpectomy specially the first
primary molar. High incidence of amalgam isthmus
f...
SSC Indications
Following Pulp Therapy
Indications
 Nash made the point that carrying out a crown prepa-
ration of a tooth solely for use as an abutment is
dest...
SSC Indications
Large, Deep Caries Caries on 3 or more surfaces
Indications for ssc
 If extensive abrasions
 Temporary restoration of fractured tooth.
 In severe cases of bruxism
 Fo...
SSC Indications
Extensive abrasions
Large, Deep Caries Enamel Hypoplasia
1st Permanent Molars
SSC Indications
Indication
 In a recent studies, Pinkerton suggested that indica-
tions for placement of a PMC should include child
patie...
FACTORS TO BE CONSIDERED IN
PRE-OPERATIVE PROCEDURE
 Dental age of the patient:
 This is recorded by the root developmen...
FACTORS TO BE CONSIDERED IN
PRE-OPERATIVE PROCEDURE
 Medically compromised/disabled children:
Some of those patients migh...
CONTRAINDICATIONS OF
STAINLESS STEEL CROWN
 If the primary molar is close to exfoliation with more than
half the roots re...
TYPES AND SIZE OF STAINLESS
STEEL CROWN
 They are available in six sizes for each primary tooth
and first permanent molar...
Untrimmed crowns
Neither trimmed
 Nor contoured
 Require lot of adaptation and are time consuming
 eg. rocky mountain
...
Pre-contoured crowns
 Festooned
 Pre-contoured
 A minimal amount of festooning
and trimming may be necessary
 eg. Ni-C...
ACCORDING TO MATERIALS USED:
 STAINLESS STEEL CROWNS
 NICKEL CHROMIUM CROWNS
 ALUMINUM CROWNS
 TIN SILVER ALLOY
 POLY...
ACCORDING TO LOCATION
 CROWNS FOR ANTERIOR TEETH
 CROWNS FOR POSTERIOR TEETH
COMPOSITION OF STAINLESS
STEEL CROWN
 1. Stainless steel crowns:
(18-8) Austenitic type of alloy is used. E.g. Rocky
Moun...
COMPOSITION OF STAINLESS
STEEL CROWN
 2. Nickel-base crowns: They are Iconel 600 types of
alloy.
-72 % nickel
-14% chromi...
 There are three general classes of stainless steel,
1) the heat hardenable 400 series martensitic types,
2) the non-heat...
 Mesio Distal Width of Crowns
 Difference is 2mm
 Average increase in size per each size is 1/3 mm
Armamentarium For SS Crown
Restorations
 Burs
 Pliers
 Instruments
 Cementing Medium
 Polishing & Isolation
Burs
CLINICAL PROCEDURE
 Evaluate the preoperative occlusion:
 Take upper and lower dental arch impressions with
alginate.
 ...
 Selection of crown:
 The correct size crown may be selected prior to the
tooth preparation by measuring the M-D dimensi...
 To produce steel crown margins of similar shapes,
examine the contours of buccal and lingual gingiva.
 Buccal and lingu...
Tooth preparation:
 The aims of the tooth reduction are:
1) To provide sufficient space for the steel crown.
2) To remove...
ANTERIORS:
Preformed SSCs are considered to be the most durable &
reliable for restoring severely carious & fractured prim...
5) Incisal reduction is required to prevent unnecessary
elongation of the tooth.
6) Lingual reduction is necessary when th...
 Recently resin veneered SSCs are available. The
problems faced by these are: can fracture while
crimping & are quiet exp...
 Apart from this,
-Polycarbonate crowns
-Strip crowns
-Artglass crowns
are also available to restore primary anterior too...
POSTERIORS:
 A number of procedures must be performed before
starting the tooth preparation.
 To eliminate the discomfor...
Isolation
 Use of rubber dam for isolation is mandatory.
 Before placing a rubber dam, check the child’s
occlusion. Obse...
 Caries removal:
 Remove the decay with large round bur in a slow speed
handpiece. After caries removal and pulp therapy...
Reduction of tooth:
 Occlusal reduction-
 Humphrey (1950) recommended that the cusps be
reduced, if necessary and that t...
 Kennedy (1976), this should approximately follow the
anatomy of the tooth to a depth of 1.0 to1.5mm, which
allows suffic...
Proximal reduction
 The second step in the process of preparing the tooth
for a steel crown should be the interproximal
r...
 Making a slice also helps to eliminate the
interproximal ledge, which seems to be the most
frustrating problem in the re...
Proximal reduction
Buccal and lingual reduction
 The third step in the preparation concerns the reduction of the buccal
and lingual surfaces...
 Savid et al (1979) compared five different types of
preparations for retention capabilities:
 (A) that recommended by M...
 Savide et al concluded that in the preparation of a
vital tooth, technique (A) might be indicated, because
of its conser...
Evaluation criteria for tooth
preparation:
 1. The occlusal clearance should be 1.5 to 2mm.
 2. Proximal slices converge...
 5. The buccal and lingual surfaces converge slightly
towards the occlusal.
 6. All the line angles in the preparation a...
Tooth preparation for permanent
dentition
 The preparation of a tooth for a permanent molar PMC is
essentially the same a...
 The walls of the crown are prepared minimally so that
they are slightly tapering with the finishing line
ending in a smo...
Crown modification for permanent
molar PMCs
 The selected crown should establish a good contact
area with neighboring tee...
Crown selection
 1)mesio distal diameter
 2) using charts
 3)trail and error method
Initial seating of the crown
 The crown is tried on the tooth by seating the lingual
first and applying pressure in a buc...
CROWN ADAPTATION
 Try crown on tooth : lingual to buccal
 Mark scratch line
 Cut 1 mm below it with scissors
 Place th...
Spedding’s Adaptation principle – 1
 Crown length
 Any point on tooth occlusal to greatest diameter is on
the visible cl...
 1 ) View from proximal surface ; buccal –lingual
surfaces converge occlusally.
 2) Any point above greatest diameter ; ...
Spedding’s Adaptation principle -
2
 Correct contours of buccal and lingual gingival
marginns of crown to gingival tissue...
Crown Trimming
Crown Trimming
 If the crown is excessively long, the crown margin may
impede complete seating, in which case crown lengt...
Crown Trimming
 It is essential that the margins of the crown are well
adapted into undercut areas, which is usually achi...
Crown Trimming
 Frequently, reduction in the mesio-distal dimension of
the crown will be necessary, especially where mesi...
Contouring pliers used
 No 112 Ball & Socket Plier
 No 137 Gordan plier
 No 114 Johnson plier ,
 Used for initial cont...
Crown contouring
 The crown is contoured using a Ball and Socket
pllier(No:114) at the junction of middle & cervical thir...
Crown contouring
 Gingival Contours
 Buccal gingival contour of E : Smile
 Buccal gingival contour of D : Stretchout ‘S...
Crimping
 The Crimping of the crown is done using crimping
pllier (No:417) to adapt the cervical margins of the
crown inw...
CROWN CRIMPING
 Evaluation;- Check with explorer
If margins open : recrimp
If overextended : start again
 Blanching : Jo...
Crimping
 Mechanical retention
 Protection of cement from exposure to oral fluids
 Maintenance of gingival health
Final adaptation of the crown:
 1) Crown must snap into place, should not be able to
be removed with finger pressure.
 2...
Final adaptation of the crown
 5)Crown is in proper occlusion and should not
interface with the eruption of teeth.
 6)Th...
Final adaptation of the crown
 9)Crown margins closely adapted to the tooth and
should not cause gingival irritation.
 1...
FINISHING
 It is safe to say that retention problems do not cause
failure of the steel restoration;
 most failures resul...
POLISHING
 While polishing the crown, margins should be blunt since
knife edge finish produces sharp ends which act as ar...
CROWN FIT
 Spedding (1984) observed that most stainless crowns
seemed acceptable when observed clinically.
 If there is ...
CEMENTATION
 Among all the cements used for cementation, the GIC
was found quiet new & very promising.
 Glass ionomer ce...
 There is, however, some evidence suggesting that the
specific choice of cement does not significantly affect
retention, ...
Steps for cementation
 Stainless steel crown should be cemented only on clean,
dry tooth. Isolation of teeth with cotton ...
 Seat the crown completely on dried tooth surface
preparation. Final placement should follow an
established path of inser...
 ZnPo4 cement can be easily removed with an explorer
or scaler. After the polycarboxylate cement is partially
set, it wil...
 Careful attention should be paid to removal of excess
cement. This can usually be effectively achieved by
running a poin...
Hall technique
 The Hall Technique is a non invasive treatment for
decayed molars teeth. Decay is sealed under
preformed ...
Hall technique
 PROCEDURE
 The Halls technique requires several appointments for
time intervals to occur, to allow separ...
MODIFICATIONS OF STAINLESS
STEEL CROWN
 In 1971 Mink and Hill reported several ways of modification of
stainless steel cr...
 Oversized tooth or the undersized crown:
 Separate the edges as needed and weld a piece of
0.004inch orthodontic band m...
Deep sub gingival caries:
Complete the indicated pulp treatment and then
restore the cavity preparation.
If subgingival ca...
Open contact:
 If the closed contact area (except for the primate
spaces) is not established, it will result in food
pack...
Open faced stainless crowns:
 The SSCs can be modified in anterior teeth by a open
faced SSC, which is simply a SSC with ...
SPECIAL CONSIDERATIONS FOR
STAINLESS STEEL CROWN
A) Quadrant Dentistry:
 When the quadrant dentistry is practiced, stainl...
 When two adjacent crowns have to be placed reduce
the adjacent proximal surface of the teeth being
restored more. The gr...
 B) Crowns in areas of space loss (Mc Evoy 1977)
 When there is an extensive and long standing caries,
the primary teeth...
 Recontour the proximal, buccal, and lingual walls of
the crown with the No. 137 or No. 114 pliers.
 Do the additional r...
Orthodontic bands
 When cementing orthodontic bands to stainless steel
crowns roughening of the internal surface of the b...
COMPLICATIONS
 Interproximal ledge:
 A ledge will be produced instead of a shoulder free
interproximal slice, if the ang...
 Crown tilt:
 Complete lingual or buccal wall may be destructed by
caries or improper use of cutting instruments. This
m...
 Poor margins:
 When the crown is poorly adapted, its marginal
integrity is reduced. Recurrent caries may occur
around o...
 Inhalation or Ingestion of crown:
 To prevent such mishaps, the rubber dam should remain in
place until cementation. It...
 The presence of cough reflex in the conscious child
will reduce the chances of inhalation and ingestion of
the crown is ...
 Occlusal wear:
 Children with tooth grinding habits may exhibit wear
through existing SSC. When this wear 0ccurs the
cr...
SS Crowns for Permanent
molars
 Indications
 Extensive Caries
 Sedative Dressing
 Interim restoration
 Endodontic out...
Crowns for primary anterior teeth
 Polycarbonate
 Strip crowns
 Pedo jacket
 Stainless steel Crowns
 Open faced SS Cr...
 NuSmile
 Whiter biter II
 Dura crowns
 Flex crowns
 Pedo- compu
 Pedo pearls
 Ceromo-metal (childers)
CONCLUSION
 The judicious combination of one of the various tooth
preparation techniques mentioned by various research
wo...
REFERENCES
 Kennedy’s Pediatric Operative Dentistry_ Curzon,
kennedy DB, Roberts
 Fundamentals of Pediatric Dentistry_ R...
 M memarpour ,D Reza M Razavi Comparison of
microleakage from stainless steel crowns margins used
with different restorat...
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Stainless steel crowns
Stainless steel crowns
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Stainless steel crowns

  1. 1. A . Mahesh kumar Pg 1st year student Dept of pedodontics & preventive dentistry Dr s&n sids
  2. 2. Contents  INTRODUCTION  HISTORY  OBJECTIVES  INDICATIONS OF STAINLESS STEEL CROWN  FACTORS TO BE CONSIDERED IN PRE-OPERATIVE PROCEDURE  CONTRAINDICATIONS OF STAINLESS STEEL CROWN  TYPES AND SIZE OF STAINLESS STEEL CROWN  COMPOSITION OF STAINLESS STEEL CROWN
  3. 3. contents  ARMAMENTARIUM FOR SS CROWN RESTORATIONS  CLINICAL PROCEDURE  TOOTH PREPARION  CROWN PREPARATION  MODIFICATIONS OF STAINLESS STEEL CROWN  COMPLICATIONS  CONCLUSION  REFERENCES
  4. 4. REFERENCES  Kennedy’s Pediatric Operative Dentistry_ Curzon, kennedy DB, Roberts  Pediatric dentistry total patient care _Stephen H.Y  Fundamentals of Pediatric Dentistry_ Richard. Mathewson  Dentistry for child and adolescent_ Ralphe Mc Donald, Avery.  Text Book Of Pedodontics_ Shobha Tandon  Clinical Pedodontics_ Sidney B Finn  Pediatric dentistry-Infancy through adolescence_ Pinkam
  5. 5.  M memarpour ,D Reza M Razavi Comparison of microleakage from stainless steel crowns margins used with different restorative materials: An in vitro studyDent Res J 2016 Jan-Feb; 13(1): 7–12.  Shah, Purvi V.; Lee, Jessica Y.; Wright;(2004) Clinical Success and Parental Satisfaction With Anterior Preveneered Primary Stainless Steel Crowns Pediatric Dentistry, Volume 26, . 391-395(5).  Preformed metal crowns for primary and permanent molar teeth: REVIEW of the Literature_ Ros C Randall. Pediatric dentistry, 24; 5:2002.  Efficacy of preformed metal crowns Vs amalgam restorations in primary molars. A systemic Review. JADA, 131:337-440; march2000.
  6. 6. INTRODUCTION  The preformed metal crown (PMC), more commonly known as the Stainless steel crown (SSC) has been used for approximately 50yrs.  Preformed metal crowns for primary molar teeth were first described by Engel followed by Humphery in 1950  First used in the late 1940’s and became commonly used in the 1960’s  The SSC offers an outstanding alternative to other restorative materials for restoration of both primary and permanent teeth
  7. 7. History  1950: The first preformed crowns marketed  1960: Significantly improved crown festooned margins to correspond to the cervical aspect of the tooth  Recently: introduced nickel-chromium crown differs distinctly from the earlier crowns. It is manufactured from the alloy Iconel with very small amount of iron as compared to older stainless steel.  Hence, Iconel 600 is not considered as a stainless steel crown.
  8. 8. Objectives  The objectives of stainless steel crown restoration are:  1) To achieve biologically compatible masticatory component and clinically acceptable restoration.  2) To maintain the form and function of tooth and where possible, the vitality of the tooth should be maintained.
  9. 9. Indications for ssc  After pulpotomy or pulpectomy specially the first primary molar. High incidence of amalgam isthmus fracture.  When three or more surfaces need restoration.  As an abutment for fixed appliances.  High caries index patient.  During general anesthesia full mouth Rehabilitation.
  10. 10. SSC Indications Following Pulp Therapy
  11. 11. Indications  Nash made the point that carrying out a crown prepa- ration of a tooth solely for use as an abutment is destructive to tooth tissue and that bands are preferable to support appliances to preserve arch space.  When both a crown and space maintainer are required, the space maintainer should be attached to a band cemented over the crown; with this arrangement, subsequent removal of the space maintainer leaves an intact and smooth crown surface.
  12. 12. SSC Indications Large, Deep Caries Caries on 3 or more surfaces
  13. 13. Indications for ssc  If extensive abrasions  Temporary restoration of fractured tooth.  In severe cases of bruxism  For replacing prematurely lost anterior teeth  For teeth deformed by developmental defects or anomalies  For teeth with hypoplastic defect  Single tooth cross bite
  14. 14. SSC Indications Extensive abrasions
  15. 15. Large, Deep Caries Enamel Hypoplasia 1st Permanent Molars SSC Indications
  16. 16. Indication  In a recent studies, Pinkerton suggested that indica- tions for placement of a PMC should include child patients who are unlikely to attend regular recall appointments or who are unlikely to be reliable preventive patients.
  17. 17. FACTORS TO BE CONSIDERED IN PRE-OPERATIVE PROCEDURE  Dental age of the patient:  This is recorded by the root development of the underlying tooth. When a primary tooth can be expected to exfoliate within 2 years of restoration, amalgam restoration can be done  Cooperation of the patient:  If the patient is uncooperative, whether it is due to age (i.e.< 3 years) or due to negative behavior, if the child is stubborn and does not want to cooperate, first a positive behavior has to be installed
  18. 18. FACTORS TO BE CONSIDERED IN PRE-OPERATIVE PROCEDURE  Medically compromised/disabled children: Some of those patients might need prophylaxis as sub gingival procedure is done (or) in poor general condition of the child, chair side GA has to be taken into account.  Motivation of the parent: Whether the parents are willing to come for dental visits for the follow-up.
  19. 19. CONTRAINDICATIONS OF STAINLESS STEEL CROWN  If the primary molar is close to exfoliation with more than half the roots resorbed or exfoliation within 6-12 months  Tooth exhibits excessive mobility  Partially erupted teeth  Where conservative restorations can be placed  In a patient with a known nickel allergy
  20. 20. TYPES AND SIZE OF STAINLESS STEEL CROWN  They are available in six sizes for each primary tooth and first permanent molars. A size 7 is available for large teeth.  Untrimmed crowns (e.g. Rocky mountain)  Pretrimmed crowns (e.g. Unitek stainless steel crowns, MN and Denvo Crowns, Denvo Co. Arcadia CA)  Precontoured crowns (e.g. Ni-Chromium Ion crowns and Unitek stainless steel crowns, MN, Sankuin copper crowns).
  21. 21. Untrimmed crowns Neither trimmed  Nor contoured  Require lot of adaptation and are time consuming  eg. rocky mountain Pre-trimmed crowns  Straight non-contoured sides  festooned to follow a line parallel to the gingival crest  Still require contouring and trimming  Eg. Unitek stainless steel crown
  22. 22. Pre-contoured crowns  Festooned  Pre-contoured  A minimal amount of festooning and trimming may be necessary  eg. Ni-Cr Ion crowns
  23. 23. ACCORDING TO MATERIALS USED:  STAINLESS STEEL CROWNS  NICKEL CHROMIUM CROWNS  ALUMINUM CROWNS  TIN SILVER ALLOY  POLYCARBONATE CROWNS  PEDO STRIP CROWNS
  24. 24. ACCORDING TO LOCATION  CROWNS FOR ANTERIOR TEETH  CROWNS FOR POSTERIOR TEETH
  25. 25. COMPOSITION OF STAINLESS STEEL CROWN  1. Stainless steel crowns: (18-8) Austenitic type of alloy is used. E.g. Rocky Mountain and Unitek. The austenitic types provide the best corrosion resistance of all the stainless steel. -10-13% nickel -17-19% chromium -67% iron -4% minor elements
  26. 26. COMPOSITION OF STAINLESS STEEL CROWN  2. Nickel-base crowns: They are Iconel 600 types of alloy. -72 % nickel -14% chromium -6-10% Fe (Iron) -0.04% carbon -0.35% manganese, 0.2% silicon
  27. 27.  There are three general classes of stainless steel, 1) the heat hardenable 400 series martensitic types, 2) the non-heat hardenable 400 series ferritic types 3) the austenitic types of chromium-nickel- manganese 200 series and chromium-nickel 300 series.
  28. 28.  Mesio Distal Width of Crowns  Difference is 2mm  Average increase in size per each size is 1/3 mm
  29. 29. Armamentarium For SS Crown Restorations  Burs  Pliers  Instruments  Cementing Medium  Polishing & Isolation
  30. 30. Burs
  31. 31. CLINICAL PROCEDURE  Evaluate the preoperative occlusion:  Take upper and lower dental arch impressions with alginate.  Pour the cast with the dental stone.  Note the dental midline and the cusp fossa relationship bilaterally.
  32. 32.  Selection of crown:  The correct size crown may be selected prior to the tooth preparation by measuring the M-D dimensions of the tooth to be restored and a Boley gauge can be used for this purpose.  If the crown is not selected before the tooth reduction, after the tooth reduction it can be selected as trial and error procedure, which approximates the M-D widths of the crown. The smallest crown that completely covers the preparation should be chosen.
  33. 33.  To produce steel crown margins of similar shapes, examine the contours of buccal and lingual gingiva.  Buccal and lingual marginal gingiva of the second primary mandibular molar resembles smiles  Buccal marginal gingiva of the most mandibular first molar (primary) and many maxillary first molars is similar to a stretched out smile having greatest occluso-gingival height located at the mesiobuccal area.  The contour of lingual marginal gingiva of all the primary molars resemble smile. The occluso-gingival height is located about midway in buccolingual direction.
  34. 34. Tooth preparation:  The aims of the tooth reduction are: 1) To provide sufficient space for the steel crown. 2) To remove the caries to have sufficient tooth for retention of the crown.
  35. 35. ANTERIORS: Preformed SSCs are considered to be the most durable & reliable for restoring severely carious & fractured primary incisors. 1) Croll described SSCs to be easy to place, fracture proof, wear resistant and attached firmly to the tooth until exfoliation. 2) The main disadvantage is the unsightly, silver metallic appearance. 3)Mesial & Distal reductions are required to clear the interproximal contacts. 4)The gingival margins should have no ledge or shoulder; instead a feather edge at the free gingival margin.
  36. 36. 5) Incisal reduction is required to prevent unnecessary elongation of the tooth. 6) Lingual reduction is necessary when the over bite is complete such that the mandibular incisors are in contact with the lingual surfaces of the maxillary incisors. 7) The only reduction that should occur on the labial surface is that which will remove caries.
  37. 37.  Recently resin veneered SSCs are available. The problems faced by these are: can fracture while crimping & are quiet expensive.  More recently a resin veneered crown- Dura Crown was introduced.  They have labial gingival margin crimped & resin adapted to the gingival edge of the anterior aspect of the crown.
  38. 38.  Apart from this, -Polycarbonate crowns -Strip crowns -Artglass crowns are also available to restore primary anterior tooth.
  39. 39. POSTERIORS:  A number of procedures must be performed before starting the tooth preparation.  To eliminate the discomfort caused by cutting the tooth and possible trauma to the soft tissues during the trial fitting of stainless steel crown, there must be adequate anesthesia of the tooth and the adjacent soft tissues.
  40. 40. Isolation  Use of rubber dam for isolation is mandatory.  Before placing a rubber dam, check the child’s occlusion. Observe for the following:  The opposing tooth has extruded due to longstanding carious lesions.  There has been mesial drift due to carious lesions changing the occlusion of the adjacent tooth.  Tooth reduction is needed so that the restored tooth can be returned to normal function
  41. 41.  Caries removal:  Remove the decay with large round bur in a slow speed handpiece. After caries removal and pulp therapy, if necessary, the previously carious area can be built up with a quick setting reinforced ZnOE cement and / or ZnPO4 cement.
  42. 42. Reduction of tooth:  Occlusal reduction-  Humphrey (1950) recommended that the cusps be reduced, if necessary and that the four sides of the tooth be reduced but as much tooth structure as possible be left for retention.  Rapp (1966) advises that the occlusion of the tooth be reduced so the height of the preparation is approximately 4mm from the gingival margin.  Mink and Bennett (1968), on the other hand, suggested a uniform occlusal reduction of 1 to 1.5mm using a 1mm bur to make grooves in the occlusal surface to guide the reduction. .
  43. 43.  Kennedy (1976), this should approximately follow the anatomy of the tooth to a depth of 1.0 to1.5mm, which allows sufficient space for the metal crown.  Reduce the occlusion by about 1.0 to 1.5mm. This is determined by comparing the marginal ridges of the adjacent teeth. (Mathewson)  In review, however, the best plan seems to be to reduce the occlusal as the initial step since; gingival bleeding will occur if the proximal reduction is done at the initial step, making the diagnosis of very small pulp exposure, difficult.
  44. 44. Proximal reduction  The second step in the process of preparing the tooth for a steel crown should be the interproximal reduction.  It has been observed that many of the difficulties countered in placing a stainless steel crown are the result of attempting to fit a round or oval crown form over a rectangular tooth preparation.  The primary principle of the technique for fitting steel crowns is to make the tooth preparation fit the crown form rather than attempt to make the crown fit the tooth preparation.
  45. 45.  Making a slice also helps to eliminate the interproximal ledge, which seems to be the most frustrating problem in the restoration of a tooth with a steel crown.  Distal reduction is required even when there is no erupted tooth distally. Failure to follow this recommendation will result in an oversized crown being fitted, which may impede the eruption of the first permanent molar
  46. 46. Proximal reduction
  47. 47. Buccal and lingual reduction  The third step in the preparation concerns the reduction of the buccal and lingual surfaces. This area seems to be the most controversial.  The questions is whether to (1) reduce the entire bulge, at least a significant portion of it or (2) permit the buccal and lingual cervical bulges to remain and reduce only the occlusal third of the preparation  The Buccal and Lingual surfaces are reduced atleast 0.5mm, with the reduction ending in a featheredge, 0.5 to 1mm into the gingival sulcus.  It is usually not necessary to reduce the buccal or lingual surfaces. In Some cases, however it may be necessary to reduce the distinct buccal bulge, particularly in primary 1st molar.  All line and point angles in the preparation are rounded and smoothed.
  48. 48.  Savid et al (1979) compared five different types of preparations for retention capabilities:  (A) that recommended by Mink and Bennett, in which only the occlusal third of both buccal and lingual surfaces is reduced.  (B) that incorporating Class II preparations, in which the buccal and lingual walls of the boxes converge toward the occlusal.  (C) that which reduces the buccal and lingual supragingivally to the crest.  (D) that which removes the supragingival bulge, extending 0.5 mm below the gingival crest, as recommended by Troutman, with all undercuts on the buccal and lingual surfaces removed.  (E) that which removes all supragingival tooth structure, permitting only part of the anatomic crown to remain (i.e. the tooth structure around which the crown would normally be adapted).
  49. 49.  Savide et al concluded that in the preparation of a vital tooth, technique (A) might be indicated, because of its conservation of tooth structure and its maximum retentive value.  Two procedures are thought to be critical for obtaining good retention (Rector et al 1985) - Precise trimming of the crown with respect to the gingival undercut. -Adapting and crimping the crown along its entire gingival margin.
  50. 50. Evaluation criteria for tooth preparation:  1. The occlusal clearance should be 1.5 to 2mm.  2. Proximal slices converge toward the occlusal and lingual, following the normal proximal contour. (Mathewson)  3. An explorer can be passed between the prepared tooth and the proximal tooth at the gingival margin of preparation.  4. The buccal and lingual surface are reduced at least 0.5 mm which the reduction ending in a feather edge 0.5 to 1mm into the gingival sulcus.
  51. 51.  5. The buccal and lingual surfaces converge slightly towards the occlusal.  6. All the line angles in the preparation are rounded and smoothened.  7. The occlusal third of buccal and lingual surfaces are gently rounded.
  52. 52. Tooth preparation for permanent dentition  The preparation of a tooth for a permanent molar PMC is essentially the same as for a cast metal crown but with a reduction in the amount of tooth tissue removed.  It is important that the future preparation needs for a cast restoration are kept in mind when preparing the tooth for a PMC.  Fitting a permanent molar PMC requires significantly more chairside time than a primary molar crown. An occlusal reduction of about 1.5 to 2 mm is needed, and carrying this out first enables the proximal reduction to be done more easily.
  53. 53.  The walls of the crown are prepared minimally so that they are slightly tapering with the finishing line ending in a smooth feather edge and placed just below the level of the free gingival tissue.  Sharp line angles should be smoothed to ensure that the crown does not bind on seating.  Radcliffe and Cullen recommended preparation of proximal slices but no preparation of the buccal or lingual tooth walls. This procedure allows the extra option of future placement of an onlay, rather than only a full coverage crown.
  54. 54. Crown modification for permanent molar PMCs  The selected crown should establish a good contact area with neighboring teeth and snap into place cervically. If required, the crown margin can be trimmed with crown scissors .  The crown gains its retention from the cervical margin area so the crown margin must be recrimped after any adjustments to ensure an accurate fit to the tooth.  Specialized crimping pliers are available for this purpose and crown-contouring pliers can be used to improve interproximal contact area morphology and to modify the gingival margin contour
  55. 55. Crown selection  1)mesio distal diameter  2) using charts  3)trail and error method
  56. 56. Initial seating of the crown  The crown is tried on the tooth by seating the lingual first and applying pressure in a buccal direction, so that the crown slides over the buccal surface into the gingival sulcus.  Resistance should be felt as the crown slips over the buccal bulge.
  57. 57. 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
  58. 58. Spedding’s Adaptation principle – 1  Crown length  Any point on tooth occlusal to greatest diameter is on the visible clinical crown, and any point on the tooth apical to greatest diameter is on an undercut surface of tooth and is not visible
  59. 59.  1 ) View from proximal surface ; buccal –lingual surfaces converge occlusally.  2) Any point above greatest diameter ; visible clinically  3) Any point below greatest diameter ; not visible clincally
  60. 60. Spedding’s Adaptation principle - 2  Correct contours of buccal and lingual gingival marginns of crown to gingival tissues  Margins apical to the greatest diameter ; good adaptation
  61. 61. Crown Trimming
  62. 62. Crown Trimming  If the crown is excessively long, the crown margin may impede complete seating, in which case crown length may be adjusted by trimming with crown shears and resmoothing and polishing the edges with an abrasive stone.  Over trimming of the crown margin should be avoided, as this may affect retention if it results in reduced adaptation of the crown margin into undercut areas.
  63. 63. Crown Trimming  It is essential that the margins of the crown are well adapted into undercut areas, which is usually achieved by crimping of the crown edges.  Special attention should be given to adaptation of the distal margin on second primary molars where the permanent molar is unerupted. An uncorrected distal overhang may result in impaction of the first permanent molar.  Care should be taken not to cause iatrogenic damage to adjacent teeth or unerupted teeth.
  64. 64. Crown Trimming  Frequently, reduction in the mesio-distal dimension of the crown will be necessary, especially where mesial drift (often due to caries) has resulted in loss of arch length.  Moderate reduction in mesio-distal dimension can be achieved by flattening of the mesial and distal contact areas of the crown with Adam’s pattern pliers.  Where mesial drift has occurred in the lower arch it may be possible to use a SSC form for the contralateral upper tooth (e.g. ULE crown form for LRE) as these SSC forms have a shorter mesiodistal dimension
  65. 65. Contouring pliers used  No 112 Ball & Socket Plier  No 137 Gordan plier  No 114 Johnson plier ,  Used for initial contouring in middle third
  66. 66. Crown contouring  The crown is contoured using a Ball and Socket pllier(No:114) at the junction of middle & cervical third of the crown with concave surface held outwards to ensure good fit.
  67. 67. Crown contouring  Gingival Contours  Buccal gingival contour of E : Smile  Buccal gingival contour of D : Stretchout ‘S’  Proximal contour of primary molars : Frown  Lingual contours of all primary molars : Smile
  68. 68. Crimping  The Crimping of the crown is done using crimping pllier (No:417) to adapt the cervical margins of the crown inwards. Johnson’s contouring pllier (No:113) can also be used.
  69. 69. CROWN CRIMPING  Evaluation;- Check with explorer If margins open : recrimp If overextended : start again  Blanching : Johnson 1987  Bitewing radiograph : More&Pink 1973 Incorrect seated sscCorrect seated
  70. 70. Crimping  Mechanical retention  Protection of cement from exposure to oral fluids  Maintenance of gingival health
  71. 71. Final adaptation of the crown:  1) Crown must snap into place, should not be able to be removed with finger pressure.  2) The crown should fit so tightly that there is no rocking on the tooth.  3) Moderate occlusal displacement forces at the margin should not displace the crown.  4)The properly seated crown will correspond to the marginal height of the adjacent tooth and is not rotated on the tooth.
  72. 72. Final adaptation of the crown  5)Crown is in proper occlusion and should not interface with the eruption of teeth.  6)There should be no high points when checked with an articulating paper.  7)The crown margin extends about 1mm gingiva to gingival crest.  8) No opening exists between the crown and the tooth at the cervical margins.
  73. 73. Final adaptation of the crown  9)Crown margins closely adapted to the tooth and should not cause gingival irritation.  10)Restoration enables the patient to maintain oral hygiene.  11)The crown seats without cutting or blanching the gingiva.
  74. 74. FINISHING  It is safe to say that retention problems do not cause failure of the steel restoration;  most failures result from poor and inadequate preparation, improper gingival adaptation, and the inability to properly visualize and determine the relationship of the crown margin to the margin of the preparation.
  75. 75. POLISHING  While polishing the crown, margins should be blunt since knife edge finish produces sharp ends which act as areas of plaque retention.  A broad stone wheel should run slowly, in light brushing strokes, across the margins, towards the center of the crown.  This will draw the metal closer to the tooth without reducing the crown height and thus improves the adaptation of the crown.  A wire brush can be used to polish the margins to a high shine. To give a fine Luster to crown, rough whiting or a fine polishing material can be used.
  76. 76. CROWN FIT  Spedding (1984) observed that most stainless crowns seemed acceptable when observed clinically.  If there is any doubt about the fit of the crown, a radiograph may be taken after cementation; however routine radiographs of all patients to determine the fit of all stainless steel crowns are not justified.
  77. 77. CEMENTATION  Among all the cements used for cementation, the GIC was found quiet new & very promising.  Glass ionomer cements are quite new and very promising. These cements have comparable strengths with zinc phosphate, release fluoride as do the silicophosphate, chelate or bond to tooth structure as the polycarboxylate and are as pulpally compatible as the polycarboxylates.  They could prove to be the best cement available for steel crown cementation.
  78. 78.  There is, however, some evidence suggesting that the specific choice of cement does not significantly affect retention, the most important retentive components being derived from correct contouring and crimping of the crown.
  79. 79. Steps for cementation  Stainless steel crown should be cemented only on clean, dry tooth. Isolation of teeth with cotton rolls is recommended. Apply Vaseline to contact areas.  Rinse and dry the crown inside and outside and prepare to cement it. ZnPO4, Polycarboxylate, or GIC are preferred.  If ZnPO4 is used, 2 coats of cavity varnish should be applied on vital tooth before cementation and cement should be of consistency so that it stings about 1½ inches from mixing pad with the spatula cement is filled in approximately 2/3rd of crown, with all inner surface covered.
  80. 80.  Seat the crown completely on dried tooth surface preparation. Final placement should follow an established path of insertion of the crown. Cement should be expressed around all margins. To ensure complete seating of the crown, handle of mirror or band pusher may be used.  Before the cement sets, ask the patient to close into centric occlusion by applying pressure through a cotton roll and confirm that the occlusion has not been altered.
  81. 81.  ZnPo4 cement can be easily removed with an explorer or scaler. After the polycarboxylate cement is partially set, it will reach a rubbery consistency. Excess cement should be removed at this stage with explorer tip.  Rinse the oral cavity and before dismissing the patient, reexamine the occlusion and the soft tissue.
  82. 82.  Careful attention should be paid to removal of excess cement. This can usually be effectively achieved by running a pointed instrument around the margins of the cemented crown and by passing knotted dental floss bucco-lingually through the contact areas prior to the cement setting.  Excess cement has been shown to be detrimental to gingival health.
  83. 83. Hall technique  The Hall Technique is a non invasive treatment for decayed molars teeth. Decay is sealed under preformed , avoiding injections and drilling. It is one of a number of biologically orientated strategies for managing caries  A General dental practitioner from Scotland, who developed and used the technique for over 15 years until she retired in 2006
  84. 84. Hall technique  PROCEDURE  The Halls technique requires several appointments for time intervals to occur, to allow separation of the teeth, placement.  the efficacy of the Hall’s technique in the management of carious primary molars with caries extending only to dentine.
  85. 85. MODIFICATIONS OF STAINLESS STEEL CROWN  In 1971 Mink and Hill reported several ways of modification of stainless steel crown when the crowns are either too large or too short.  Undersized tooth or the oversized crown:  This commonly occurs when, due to a long-standing interproximal caries, space loss has occurred. To reduce the crown circumference, a V cut is made up of the buccal surface to the occlusal surface.  The cut edges are reapproximated to overlap one another making the crown circumference smaller. The crown is tried on the tooth and amount of overlapping necessary is marked on the crown. The overlapped edges are then spot-welded.  The crown is polished with a rubber wheel and fine abrasives.
  86. 86.  Oversized tooth or the undersized crown:  Separate the edges as needed and weld a piece of 0.004inch orthodontic band material across the cut surface. After contouring, apply the solder to fill any microscopic deficiency in seal, polish the soldered crown.
  87. 87. Deep sub gingival caries: Complete the indicated pulp treatment and then restore the cavity preparation. If subgingival caries occurs interproximally, the unfestooned crown will be deep enough to cover the preparation.
  88. 88. Open contact:  If the closed contact area (except for the primate spaces) is not established, it will result in food packing, increased plaque retention and subsequently gingivitis.  This problem can be solved by selection of a larger crown or exaggerated interproximal contour can be obtained with a 112 (ball and socket) plier to establish a close contact. Interproximal contour can also be build by addition of a solder.
  89. 89. Open faced stainless crowns:  The SSCs can be modified in anterior teeth by a open faced SSC, which is simply a SSC with the labial surface trimmed away & restored with a resin veneering (Croll, 1998)
  90. 90. SPECIAL CONSIDERATIONS FOR STAINLESS STEEL CROWN A) Quadrant Dentistry:  When the quadrant dentistry is practiced, stainless steel crowns are to be placed on adjacent teeth. Few points, which are to be considered here are (Nash 1981).  Prepare the occlusal reduction of one tooth completely before beginning the occlusal reduction of the other tooth because there is tendency to under reduce both, when reduction on both the teeth is done simultaneously.
  91. 91.  When two adjacent crowns have to be placed reduce the adjacent proximal surface of the teeth being restored more. The greater reduction will ease the placement of the crowns and interproximal approximation.  Both crown should be trimmed, contoured, and prepared for cementation simultaneously to allow for adjustments in the interproximal spaces and establish proper contact areas.  To get these adjustments, adapt and seat the crown on the most distal tooth first and proceed mesially.
  92. 92.  B) Crowns in areas of space loss (Mc Evoy 1977)  When there is an extensive and long standing caries, the primary teeth shift into the interproximal contact areas. As a result, the crown required to fit over the buccolingual dimensions will be too wide than mesiodistal to be placed and the crown selected to fit over mesiodistal space will be too small in circumference.  Select larger crown, which will fit over the tooth's greatest convexity.  Reduce the mesiodistal width by grasping the marginal ridges of the crown with Howe utility pliers and squeezing the crown.
  93. 93.  Recontour the proximal, buccal, and lingual walls of the crown with the No. 137 or No. 114 pliers.  Do the additional reduction of buccal and lingual surface of tooth and select a smaller crown, if this crown is difficult to place.
  94. 94. Orthodontic bands  When cementing orthodontic bands to stainless steel crowns roughening of the internal surface of the band and external surface of the crown prior to cementation has been shown to improve retention.
  95. 95. COMPLICATIONS  Interproximal ledge:  A ledge will be produced instead of a shoulder free interproximal slice, if the angulation of the tapered fissure bur is incorrect. Failure to remove this ledge will result in difficulty in seating the crown.  When the adjacent tooth is partially erupted, and the contact is poorly established, the interproximal slice is difficult to prepare. To clean the contact area, extensive subgingival tooth reduction is required which may result in formation of a ledge or damaging the erupting tooth. In such a case, it may use to delay crowning until contact areas are properly established.
  96. 96.  Crown tilt:  Complete lingual or buccal wall may be destructed by caries or improper use of cutting instruments. This may result in finished crown tilting towards the deficient side. Placement of restoration prior to crowning provides a support to prevent crown tilt, the alloy as core. The clinical significance of crown tilting is minimal unless it occurs on young permanent molars, where supra-eruption of the opponent tooth may occur.
  97. 97.  Poor margins:  When the crown is poorly adapted, its marginal integrity is reduced. Recurrent caries may occur around open margins, chances of plaque retention and subsequently gingivitis increases with marginal discrepancy  Aesthetics : Parents complain about the appearance . In this case a mesiobuccal facing can be placed after the crown has been cemented into place {Robert 1983}
  98. 98.  Inhalation or Ingestion of crown:  To prevent such mishaps, the rubber dam should remain in place until cementation. It prevents accidental swallowing or aspiration of a crown. Sometimes sudden movement may result in ingestion of the crown, if the rubber dam is not used. In this regard, floss attachment by means of impression compound on the occlusal of the crown is the preferred practice by some clinicians.  If the crown is in bronchi or lung, medical consultation will probably result in attempt to remove it by bronchoscopy. 
  99. 99.  The presence of cough reflex in the conscious child will reduce the chances of inhalation and ingestion of the crown is more likely. Ingestion is of less consequence, as the crown will usually pass uneventfully through the alimentary tract within 5-10 days. But it should be diagnosed by absence of the crown on a chest radiograph.
  100. 100.  Occlusal wear:  Children with tooth grinding habits may exhibit wear through existing SSC. When this wear 0ccurs the crown should be replaced. If the wear is confined to a small area on the tip of a cusp then a small amalgam restoration can be placed in the hole in the wear facet, so as to preclude the cement dissolving away and leaving a defect.
  101. 101. SS Crowns for Permanent molars  Indications  Extensive Caries  Sedative Dressing  Interim restoration  Endodontic outcome uncertain  Traumatically #ed Posterior tooth  Developmental malformation
  102. 102. Crowns for primary anterior teeth  Polycarbonate  Strip crowns  Pedo jacket  Stainless steel Crowns  Open faced SS Crowns  Cheng Crowns  Kinder krowns
  103. 103.  NuSmile  Whiter biter II  Dura crowns  Flex crowns  Pedo- compu  Pedo pearls  Ceromo-metal (childers)
  104. 104. CONCLUSION  The judicious combination of one of the various tooth preparation techniques mentioned by various research workers and proper manipulation of metal crown in skillful hands, along with continuous improvements which have been made in the anatomic configuration of the crown, would lead to a wonderful restoration with high durability.
  105. 105. REFERENCES  Kennedy’s Pediatric Operative Dentistry_ Curzon, kennedy DB, Roberts  Fundamentals of Pediatric Dentistry_ Richard. Mathewson  Dentistry for child and adolescent_ Ralphe Mc Donald, Avery.  Clinical Pedodontics_ Sidney B Finn  Pediatric dentistry-Infancy through adolescence_ Pinkam  Text Book Of Pedodontics_ Shobha Tandon.
  106. 106.  M memarpour ,D Reza M Razavi Comparison of microleakage from stainless steel crowns margins used with different restorative materials: An in vitro studyDent Res J 2016 Jan-Feb; 13(1): 7–12.  Shah, Purvi V.; Lee, Jessica Y.; Wright;(2004) Clinical Success and Parental Satisfaction With Anterior Preveneered Primary Stainless Steel Crowns Pediatric Dentistry, Volume 26, . 391-395(5).  Preformed metal crowns for primary and permanent molar teeth: REVIEW of the Literature_ Ros C Randall. Pediatric dentistry, 24; 5:2002, pg489.  Efficacy of preformed metal crowns Vs amalgam restorations in primary molars. A systemic Review. JADA, 131:337-440; march2000.
  107. 107. Thank you

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