CONTENTS

STAINLESS STEEL CROWNS IN PEDIATRIC DENTISTRY

PRESENTED BY: RISHU CHWLA MDS STUDENT DEPT. OF PEDIATRIC & PREVENTIVE DENTISTRY

CONTENTSINTRODUTIONDEFINITIONGOALS AND OBJECTIVESIdeal characteristics of crownsCLASSIFICATIONSTAINLESS STEEL CROWNSClassificationCompositionIndicationsContraindicationsAdvantagesDisadvantagesPreoperative evaluationClinical procedure

Stainless steel crowns for permanent molars

special considerations for stainless steel crowns:Quadrant dentistryCrowns in areas of space lossPreparing a stainless steel crown adjacent to a class-ii amalgam restorationsStainless steel crown modifications

The undersized tooth or the oversized crownThe oversized tooth or the undersized crownDeep subgingival cariesOpen contactOpen faced stainless steel crowns

complications of stainless steel crown restorations

Causes of Stainless steel crown failures

Conclusion

references

INTRODUCTIONStainless steel crowns were introduced to Pediatric Dentistry by the Rocky Mountain Company in 1947 and made popular by W. P. Humphrey in 1950. Until then the treatment for grossly decayed primary teeth was extractionsWhile originally intended for the restoration of posterior primary and young permanent teeth, its use was expanded to badly decayed anterior teeth

CROWN

Full coverage restoration given in grossly carious tooth so as to prevent loss of remaining tooth structure and to maintain normal form and function of the tooth.

Anterior teethPosterior teeth

Goals:

To achieve biologically compatible, masticatorily competent and clinically acceptable restoration.

To maintain the form and function and where possible, the viability of the tooth.

Objectives:

Elimination of all carious tooth structureTo reestablish proper occlusal contacts.To reestablish normal mesio-distal and coronal dimension for maintenance of arch length and spatial relationship.To cause no periodontal pathosis due to coronal contours or marginal fit.Minimum of treatment time for crown placement. Avoid patient discomfort during or after crown placement.To create a restoration that will not require further clinical treatment before natural exfoliation of the tooth.

Ideal characteristics of crowns:

Represent the natural tooth.Match with the color of the adjacent teeth.The dimension of the crown i.e. the mesiodistal width should be in proportion.Restore the function and esthetics of the tooth it represents and should help in maintaining adequate arch length.Biocompatible with the surrounding structures. Economical.

CLASSIFICATION

According to form and Contour:

Untrimmed, uncontoured, uncrimped crowns.

Pre-contoured and untrimmed crowns.

Pretrimmed, precontoured and precrimped crowns.

According to materials used:

Stainless Steel Crowns.

Nickel Chromium Crowns.

Polycarbonate crowns.

Pedo strip crowns.

According to the location:

Crowns for anterior teeth.

Crowns for posterior teeth.

STAINLESS STEEL CROWNS

Introduced by Humphrey as chrome-steel crowns in 1950. Provides a simple and expeditious means of restoring extensively carious primary teeth.

Introduced by Humphrey as chrome-steel crowns in 1950. Provides a simple and expeditious means of restoring extensively carious primary teeth. Preformed Metal Crowns (PMCs) Classification:

According to Trimming

Untrimmed Crowns e.g. Rocky Mountain

Neither trimmed nor contouredRequire lot of adaptationAre time consuming

According to Trimming

Pretrimmed Crowns e.g. Unitek & Denovo

Have straight non contoured sides but are festooned to follow a line parallel to the gingival crest

Still require some contouring & festooning

According to Trimming

Precontoured Crowns e.g. Nickel-Chrome Ion crowns & Unitek

Are festooned & precontoured, though minimal amount of festooning & trimming may be necessary

Preveneered SSC:

Resin based composite bonded to occlusal and buccal surface of crown.

More acceptable estheticallyII. According to Composition:

SSC - 3M

Nickel-chromium Crowns - Iconel

According to Occlusal Anatomy:

Ion - Compact Occlusal anatomy Unitek - Best Occlusal anatomy Rocky mountain - Occlusally small Ormaco - Smallest and least occlusally carved COMPOSITIONStainless Steel Crown 17 19 % Chromium10 13 % Nickel67 % Iron4 % Minor elements (0.08 0.12% carbon)

Austentic type provide the best corrosion resistance of all stainless steels.

21 COMPOSITIONNickel Base Crowns Inconel 600 type of alloy72 % Nickel14 % Chromium6 10 % Iron0.04 % Carbon0.35 % Manganese0.2 % Silicon

These alloys have good formability & ductility necessary for clinical adaptation of crowns & wear resistance to resist opposing forces.

COMPOSITIONStainless steel are low carbon alloy steels that contain at least 11.5% chromium. There are three general classes of stainless steel :Heat hardenable 400 series martensitic typesNon heat hardenable 400 series ferrite typesAustenitic types of chromium nickel manganese 200 series Chromium nickel 300 series.

Rocky mountain and Unitek stainless steel crowns use the austenitic types for their crowns referred to as 18-8 since they contain about 18% chromium and 8% nickel.

The austenitic types have high ductility , low yield strength , which make them outstanding for deep drawing and forming procedures.

They are readily welded and can be work hardened to high levels.

The austenitic types provide the best corrosion resistance of all of the stainless steels.

Chromium contribute to the formation of a very thin surface film , probably oxide that protects against corrosive attack.

INDICATIONS OF STAINLESS STEEL CROWNS

Extensively carious primary or young permanent teeth

For teeth deformed by developmental defects or anomaliesEnamel dysplasiasDentinogenesis imperfecta

Following Pulp therapy

Large, Deep Caries Caries on 3 or more surfaces

Temporary Restoration of a Fractured Tooth

As a part of Space Maintainer

In severe cases of Bruxism (an additional layer of solder is added on to the occlusal surface. This is called as Crolls Technique)

For teeth with Hypoplastic defects As a Preventive Restoration In a Handicapped Child Single tooth Crossbite For Replacing Prematurely Lost Anterior TeethPinkenon suggested that indications for placement of PMC should include child patients who are unlikely to attend regular recall appointment

Teeth approaching exfoliation within 6 to 12 months should not be fitted within PMCAAPD Consensus on Use of SSCs Children at high risk exhibiting anterior tooth decay and/or molar caries may be treated with SSCs to protect remaining at-risk surfaces.

Extensive decay, large lesions or multiple surface lesions in primary molars should be treated with SSCs.

Strong consideration for use of SSCs in children who require GA

INDICATIONS IN PERMANENT MOLAR TEETHInterim restoration of a broken down or a traumatized tooth until construction of a permanent restoration can be carried out

Financial considerations

Teeth with developmental defects

Restoration of a permanent molar which requires full coverage but is only partially erupted.

30Requirement of SSC is more frequently in deciduous than permanent teeth because :

In a relatively small deciduous tooth, neglected caries can destroy the tooths integrity faster than in the larger permanent tooth.

The morphology of primary molar differs from permanent :Enamel and dentin are much thinner than permanent toothGreatest convexity at the cervical third of the crownPulp is large with prominent pulp horn

Primary vs. Permanentcontraindications:

relative contraindications include:

For anterior teeth due to poor aesthetics.

Primary posterior teeth in which conservative amalgam restorations can be placed. Tooth near to exfoliation (in deciduous teeth in which half of roots have resorbed).

As permanent restoration in permanent dentition.

advantagessuperior to multisurface amalgam restorations with respect to both life span and replacement and most advantageous system, of restoration because of its retention and resistance.

They are acceptable to both the patient and the dentist.

cost effective disadvantages Untrimmed crowns: (Rocky Mountain):

These are neither trimmed nor contoured.

Require lot of adaptation and thus are time consuming

Availability of Stainless Steel crowns:

six sizes for each primary tooth and permanent first molars.

Sizes 4 and 5 .. most often used.

size 7 extra large teeth.

Also available for primary incisors and canines and permanent incisors form

ArmamentariumCrown cutting burs- pear shaped, tapered fissure burs

Howe pliers, No-114 contouring plier, crimping plier, No.112 ball & socket plier.

Crown and bridge scissors.

Crown remover.

Stone, finishing burs.

Miscellaneous: Straight hand piece micromotor, articulating paper etc.

Green stone, rubber wheel, wire brush Preoperative evaluationDental Age of the Patient

Co-Operation of the Patient

Motivation of the Parents

Medically Compromised/Disabled Children

STAINLESS STEEL CROWNS VS. AMALGAMS

70% - 75% of large multi surface silver amalgams placed at ages 2-5 will need replacement before the age of 8.

Have a longer clinical life span than 2 or 3 surface amalgam restorations (survival time up to 40 months as compared to amalgam which is 30-32 months).

Rate of replacement is also low ( 3%) as compared to Class II amalgam restorations ( 15%).

Braff in 1975 reported success rate of 70% for crowns and 11% for amalgams.

Gordon 1978, Lilienfeld & Lilienfeld 1980 showed that crowns placed in children age 4 or younger demonstrated a success rate approximately twice that of Class II amalgams, for each year up to 10 years of service

Dawson ( 1981) compared lifespan of SSC and two surface amalgams. It was determined that SSC was the restoration of choice for primary molars, especially for multisurface restorations in the first molar before the eruption of the 1st permanent molar.

data form studies Comparing Preformed Metal Crowns with Multisurface Amalgam Restoration in Primary Molar TeethStudy reference and dateMultisurface amalgamPreformed metal crownStudy durationNumber PlacedFailuresNumber PlacedFailuresYearsBraff 1975150131(87%)7619 (25%)2.5Dawson et al 198110272 (71%)648(13%)2 minimumMesser & Levering 19881177255(22%)33140(12%))5Roberts and Sherriff 199070682 (12%)67313(2%)10Einwag and Dinninger 19966638 (58%)664(6%)8Raw data total (raw data %)2201578 (26%) 121084(7%)Mean=5yPMCs demonstrated greater longevity and reduced retreatment need Advantages of stainless steel crowns over amalgam restorations. low costless chair timeprotection of tooth from further decayAvailability of many sizesDurabilityresistance to tarnishabsence of mercurythe ability to regain vertical dimension and retain occlusion,maintenance of morphologic form to preserve the health of gingival tissuesthe ability to preserve arch lengthAdminister L.A

2. Isolation

3. Remove the decay

4. Selection of crown = mesial-distal dimensions of the tooth The crown must be large enough to fit over the height of contour of the tooth

If the crown is not selected before the tooth reduction, then after the tooth reduction it can be selected as a trial and error procedure which approximates the mesial-distal width of the crown. The smallest crown that completely covers the preparation should be chosen.

CLINICAL PROCEDURE FOR POSTERIOR TEETH

Impingement upon the primate space by an oversized crown may prevent early mesial migration of the mandibular first permanent molar from a cusp to cusp occlusion into an Angle Class I relationship (Baume 1950).

Similarly, overcontoured and oversized steel crowns on second primary molars can prevent the normal eruption of the first permanent molars.

CONSIDERATIONS ABOUT TOOTH PREPERATIONHumphrey (1950) recommended that the cusps be reduced if necessary , and that the four sides of the tooth be reduced but as much as tooth structure as possible be left for retention.

Rapp advises that the occlusal of the tooth be reduced so the height of the preparation is approximately 4mm from the gingival margin.

Mink and Bennett, suggest a uniform occlusal reduction of 1 to 1.5mm using 1mm bur to make grooves in the occlusal surface to guide the reduction.

Troutman (1976)recommends the occlusal surface to be reduced to 1mm and Kennedy (1976) recommended the reduction to be 1.5 to 2mm.

Aims of tooth preparation Provide sufficient space for the steel crown.

Remove the caries

Leave sufficient tooth for retention of the crown.

Occlusal Reduction

69 L or 169 L bur or a tapered diamond bur

Depth cuts of 1.0-1.5 mm

Proximal reduction.

Wedges are used to separate the adjacent teeth

10 degree convergent to the occlusal surface

Feather edge margin

Buccal/Lingual reduction

Generally not required ( infact undercut aids in retention).

Prominent buccal bulge in 74,84 Done in cases of Prominent cusp of carabelli in 55,65 & first molars.

Round all line angles:

By holding bur at 30- 400 angle.

Sweeping motion in mesio distal direction

Evaluation Criteria for Tooth Preparation:

The occlusal clearance is 1.5 to 2mm. (A sheet of wax may be used to indicate areas of insufficient reduction.)

The proximal slices converge towards the occlusal and lingual, following the normal proximal contour.

An explorer can be passed between the prepared tooth and the proximal tooth at the gingival margin of preparation.The buccal and lingual surfaces are reduced at least 0.5 mm with the reduction ending in a feather edge, 0.5 to 1mm into the gingival sulcus.

The buccal and the lingual surfaces converge slightly towards the occlusal.

All the point and the line angles in the preparation are rounded and smoothed.

The occlusal third of buccal and lingual surfaces are gently rounded.

Which surface should be reduced first Proximal or Occlusal ??????If proximal reduction is done first , some gingival bleeding will occur.

If blood gets on preparation, it will make diagnosis of very small pulp exposure difficult.

Occlusal reduction first, removing any caries along.

perform pulp therapy and then proceed with proximal reduction.

seating the crown

Seat 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 slip over the buccal bulge.

No blanching of gingival tissue should occur.

Adjacent proximal contact must be maintained.

The occlusal relationship must be reestablished as per the original status.

Adjacent marginal ridge heights should be at the same level.

If there is a discrepancy in marginal ridge heights, following situations may exist:

The selected crown may be too long A gingival ledge may be present Contact may still exist between the adjacent teeth There may be inadequate occlusal reductionGingival blanching slight trimming of the crown with scissors or a wheel stone.

The crown normally extends 1mm into the gingival sulcus.

level of the gingival crest is marked on the crown using a sharp instrument and the crown is trimmed 1mm below this mark.

adaptation of the crown:

Crown Contouring

Ball and socket pliers in the middle 1/3rd of the crown to produce a belling effect.

Gives the crown a more even curvature.

Adaptation of the gingival 1/3rd of the crown is done with the 137 Gordon pliers to reduce the marginal circumference of the crown.

Principles for obtaining optimal adaptation (by Spedding 1984) 1. Crown Length: - Be 1mm sub-gingivally. - Extend slightly apical to tooths height of contour

2. Shape of the crown's gingival margins

Outline for the buccal and lingual gingiva for 2nd primary molars is similar to a smile. The buccal gingiva of the 1st primary molar is that of a stretched out S The proximal contours of the primary teeth approximates that of a frown.

CROWN CRIMPING

Done for final close adaptation of crown to tooth surface.

Done in cervical margin 1 mm circumferentially.

No. 137 plier, No. 800- 417 (Unitek) plier can be used.

Before crimping & after crimping. Mechanical retention of the crown

Protection of cement from exposure to oral fluids

Maintenance of gingival health

Checking the Final Adaptation of the Crown:

snap into place & an audible click under biting pressure on a tongue blade / band seater should be there.

no rocking on the tooth.

The properly seated crown will correspond to the marginal ridge height of the adjacent tooth

Crown is in proper occlusion

The crown margin extends about 1 mm gingival to gingival crest.

No opening exists between the crown and the tooth at the cervical margins.

Restoration enables the patient to maintain oral hygiene.

FINISHING AND POLISHING

Done to avoid complications associated with plaque accumulation & gingival inflammation due to rough & unpolished restoration

A broad stone wheel should run slowly, in light brushing strokes, across the margins towards the center of the crown. Blunt margins

draw the metal closer to the tooth without reducing the crown height and thus improves the adaptation of the crown.

wire brush .polish the margins to a high shine. rouge whiting or fine polishing material . To give a fine luster to crown

RADIOGRAPHIC CONFIRMATION OF THE GINGIVAL FIT:

To verify proximal marginal integrity.

If the crown is too long, there is still an opportunity to reduce the length.

If it is too short, then adding orthodontic band or adaptation of another crown is indicated.

Cementation of the crown:

Rinse and dry the crown and tooth

Fill the cement to approx. 2/3rd of crown from inside.

Apply Pressure by opposite end of mouth mirror or tongue blade.

Ask the patient to close in centric occlusion before final setting of cement.

Remove all excess cement when it sets.67CLINICAL PROCEDURE FOR ANTERIOR TEETHAnesthetize the teeth to be restored and place the rubber dam.Select a primary stainless steel crown with a mesio-distal incisal width equal to the tooth to be restored by placing the incisal edge of a stainless steel crown against the unprepared tooth.Remove decay with a medium to large round bur in a slow speed handpiece. If pulp therapy is required, do it at this time

68Using a 169L bur or a fine tapered diamond, reduce the incisal edge by 1.5mm.Reduce the facial surface by 1mm and the lingual surface by 0.5mm. Create a feather-edge gingival margin. Round all line angles.Try the pre-selected crown on the tooth.

Anterior crowns are manufactured with an ovoid shape with a small facio-lingual dimension. Change the shape to allow the crown to passively slip on the tooth. Squeeze the crown slightly mesio-distally with a pair of Howe no. 110 pliers to increase the facio-lingual dimension.

Reseat the crown. The crown should extend 1mm under the gingival margin. The fit of the crown should be snug without rockingTrimming, if necessary, is best done with a heatless stone on a straight slow speed handpiece followed by polishing with a rubber point.

Contouring and crimping are necessary to insure a good marginal fit. Use a no. 137 Gordon plier to adapt the margin. Check the marginal fit with an explorer.

Seat and cement the crown. Remove excess cement from the crown with a wet gauze. The cement must be completely set before preparation and placement of the open faced veneer.

TRENDS IN STAINLESS STEEL CROWNS:Although, more durable and retentive than amalgam or composite they are unaesthetic, especially on the anterior teeth. With aesthetics of their childs smile of extreme importance to parents, many opted for extraction and prosthetic replacement of severely decayed teeth rather than placement of stainless steel crowns.The advent of composite bonding, allowed for a composite facing to be placed on the facial surface of the tooth, thus improving aesthetics. Open faced stainless steel crowns combine strength, durability and improved aesthetics, however they are time consuming to place as the composite facing cannot be placed until the stainless steel crown cement sets.Bleeding of the color of the metal margins surrounding the composite adds a grayish tinge to the tooth that is accentuated next to the white enamel of an adjoining or opposing primary tooth.Open Faced Stainless Steel Crown TechniqueOnce the cement is set, cut a labial window in the cemented crown using a no. 330 or no. 35 burExtend the window:Just short of the incisal edgeGingivally to the height of the gingival crestMesio-distally to the line angles

Using a no. 35 bur remove the cement to a depth of 1mm.Place undercuts at each margin with a no. 35 bur or with a no. round burSmooth the cut margins of the crown with a fine green stone or white finishing stone.

After using a glass ionomer liner to mask differences in color between remaining tooth structure and cement place a layer of bonding agentPlace resin based composite into the cut window forcing the material into the undercuts and polymerize.

Add additional material in 1mm increments and polymerize.Finish the restoration with abrasive disks.Run the disks from the resin to the metal at the margins so as not to discolor the resin with metal particles.

Repeat the procedure for the remaining teeth.

ADVANTAGES:

Esthetics are often improved.

Tooth structure is accessible for pulp testing.

Choice of cementGlass ionomer are hybrid of silicate and polycarboxylate. comparable strengths with zinc phosphate release fluoride as do the silicophosphatechelate or bond to tooth structure and pulpally compatible as polycarboxylates.

Disadvantage include the radiolucency and present lack of long term clinical efficacyLuting Cement Film thickness S.time Comps(mm) (min.) strength (MPa)ZnPO4 18 5.5103.5ZnOE 25 4-10 27.6Polycarboxylate 21 5.5 55.2GIC 24 6.5 86.2No significant difference in retentivity of stainless steel crown with the use of either of the three (glass ionomer, Zinc phosphate and zinc polycarboxylate) luting agents.Berg et al evaluated microleakage of three luting agents used with stainless steel crowns. They found that glass ionomer cement provides comparable protection to that of polycarboxylate and zinc phosphate cementsPlacement technique in permanent molarsThe anatomical variations and practical considerations that alter the rationale of the preparation for a permanent tooth compared with that of a deciduous tooth such as:

There are no gross cervical bulges on permanent teeth that facilitate retention of the crown.

Cusp heights are much greater in permanent teeth.

Conservation of tooth structure is more crucial for teeth of the permanent dentitionUnlike the primary molar crowns , those for permanent teeth cannot be left in hyperocclusion

When a caries lesion has extended subgingivally , the original tooth morphology should be restored either with bonded composite resin or with amalgam restoration before commencing the crown preparation. It is nor recommended to use cement only in these areas.For each permanent molar in the arch there are 6 sizes of crowns, ranging in mesio-distal dimension from 10.7 mm to 12.8 mm, increasing in approximately 0.4 mm increments. Principles for obtaining optimal adaptation (by Spedding 1984) 1. Crown Length: - Be 1mm sub-gingivally. - Extend slightly apical to tooths height of contour

2. Shape of the crown's gingival margins

Outline for the buccal and lingual gingiva for 2nd primary molars is similar to a smile. The buccal gingiva of the 1st primary molar is that of a stretched out S The proximal contours of the primary teeth approximates that of a frown.

Hall techniqueResearchers in the UK have attempted to cement stainless steel crown without any caries removal or tooth preparation directly over the carious tooth. The results to date show that this simple technique can provide successful restorations in the short term. This technique of stainless steel crown placement, is not advocated at present, the findings of ongoing studies using this technique may change the recommendations for its use in the coming years.

Concerns about exfoliationThese crowns donot interfere in any way with normal exfoliation of primary molarsStainless steel crown and primary molar crown being exfoliated together

Retention of stainless steel crownsSavide et al compared five different types of preparations for retention capabilities :

A. occlusal third of both buccal and lingual surfaces is reduced. (Mink and Bennett) B. That incorporating class II preparations, in which the buccal and lingual walls of the boxes converge towards the occlusal.

C. That which reduces the buccal and lingual supragingivally to the gingival crest.

D. That which removes the supragingival bulge, extending 0.5mm below the gingival crest (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.

They concluded that mechanical retention does not significantly contribute to the separation resistance of steel crown.

The results were consistent with Mathewson et al who concluded that retention was related more to the cementation than to mechanical adaptation.

Humphrey and Full et al suggested that retention of stainless steel crowns is related to minimal tooth reduction and contact between the margins of the crown and the tooth.

Mathewson et al reported that mechanical retention alone is not a significant factor contributing to crown retention

Yates and Hemberee found that the Unitek crown is significantly more resistant to removal than the Ion and Rocky Mountain crownsMyers et al reported that crown retention with cement was significantly higher than mechanical retention alone. Stainless steel crown retention with polycarboxylate or zinc phosphate cement was significantly greater than crown retention with zinc oxide eugenol cement.

Savide et al observed that tooth preparations which maintain the greatest amount of buccal and lingual tooth structure are the most retentive.

Rector et al noticed no significant difference in the retention of stainless steel crowns using five different tooth preparations.Longevity of Stainless steel Crowns for permanent teeth:

The major factors concerning the longevity of the crown are gingival recession, recurrent marginal caries dissolution of the cement wearing through on the occlusal surface of the crown.

Stainless steel crown for permanent teeth are not substitute for the precision cast restorationspecial considerations for stainless steel crowns:

quadrant dentistry:

Prepare the occlusal reduction of one tooth completely before beginning the occlusal reduction of the other toothReduce the adjacent proximal surface of the teeth being restored more than when only one tooth is restored. 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.Crowns in areas of space loss (mc evoy 1977):

Extensive and long standing caries, the primary teeth shift into the interproximal contact areas. crown required will be too wide M-D over the M-D space will be too small in circumference.

Select a larger crown which will fit over the tooths greatest convexity.Reduce the M-D width by grasping the marginal ridges of the crown with Howe utility pliers and squeezing the crown.Recontour the proximal, buccal and lingual walls of the crown with the No. 137 or No. 114 pliers.

Or The crown is rotated slightly mesiobuccally so that it is rotated slightly out of the arch.

preparing a stainless steel crown adjacent to a class-ii amalgam restorations (mc. Evoy 1985)

Crown reduction is complete and the crown is adapted.

matrix band and wedges are placed. Amalgam is inserted and carved.

With the matrix band in place, the crown is removed safely without fracturing the amalgam.

Then remove the matrix band and the final carving of amalgam is done, as there is good visibility and access to the proximal box area.

Now complete the crown adaptation and cement the crown. Stainless steel crown modificationsthe undersized tooth or the oversized crown: - space loss as a result of long standing interproximal caries. - The crown is cut vertically along the buccal wall.

- The free crown margins are approximated and spot-welded to reduce the crowns dimensions.

the oversized tooth or the undersized crown: - A vertical cut is made on the buccal surface of the crown.

- The margins are pulled apart and an additional piece of stainless-steel band material is spot-welded to the buccal surface, increasing the dimensions of the crown.

- After contouring, solder is applied to fill any microscopic deficiency in seal.

-The crown is polished and cemented.

Deep subgingival caries:

interproximal caries ..

The unfastened Rockey Mountain crown

Lengthening the crown with a spot welded and soldered piece of band materialopen contact:

food packing increased plaque retention and subsequently gingivitis.

Select a larger crown

Alternatively, exaggerated interproximal contour can be obtained with a No. 112 (ball-and-socket) plier to establish a closed contact .

Localized addition of solder can also build out the interproximal contour.

complications of stainless steel crown restorations:

interproximal ledge:

Crown does not seat proximallyIt is removed using a tapered fissure bur.

crown tilt:

Destruction of a complete lingual or buccal wall by caries or overzealous use of cutting instruments may result in the finished crown tilting towards the deficient side.

Commonly seen on lingual aspect of mandibular primary molars.

Placement of an amalgam alloy, or glass-ionomer cement restoration

poor margins:

Imperfect adaptation.

Open margins.

Recurrent caries plaque retention and subsequent gingivitis

Premature exfoliation of that tooth Periodontal concerns:

Henderson (1973) reported that the plaque accumulation index for stainless steel crowned teeth was generally lower than that for the entire mouth.

A higher degree of gingivitis associated with crowns having a poor fit.

Myers (1975) reported a close relationship between the presence of marginal gingivitis and defects in the adaptation of the crown margin.

aesthetics:

First primary molars.

Mesiobuccal facing can be placed after the crown has been cemented into place.

Roberts (1983)

nickel allergy:

Feasby et al (1988), reported an increased nickel-positive patch test result in children 8 to 12 years of age who had received old formulation nickel-chromium crowns.

Nickel hypersensitivity is more prevalent in females than males and is considered to be associated with pierced ears or metal buttons in clothing.

Two studies (Kerosuo H. 1996 and Hoogstraten IMW 1991) reported that orthodontic treatment with nickel-containing stainless steel appliances, if carried out before ear piercing, appeared to reduce the prevalence of nickel hypersensitivity.

inhalation or ingestion of the crown:

Immediate chest X-ray is mandatoryIf the crown is in the bronchi or lung, medical consolation and referral will probably result in an attempt to remove it by bronchoscope. The presence of a cough reflex in the conscious child fortunately reduces the chances of inhalation, ingestion of the crown being more likely.The Stainless steel crown will usually pass uneventfully through the alimentary tract within 5-10 days. The parent should assume the unpleasant task of locating the expelled crown.

Allen described the most common errors in using stainless steel crowns as Unnecessary destruction of hard tissue in preparationlack of a feather edge around the entire circumference, Failure to round all line angles which may prevent correct seating of the crown incorrect selection of the crown size.More and Pink described the causes of stainless steel crown failurepulp necrosisectopic eruption,improper contact which may cause space loss,gingivitis around the crowninsufficient retention leading to loss of a crownexcessive occlusal wearCARE AFTER TOOTH RESTORATION WITH SSC

Regular diet may be resumed after anesthetic effects are worn off. Warm saline rinses.Proper brushing and flossingStainless steel crowns on permanent teeth may need to be replaced by a cast crown when the child is in his/her mid to upper teens or later in life.

CONCLUSIONThe stainless steel crown enjoys a wide range of use in clinical Pediatric Dentistry and will continue to be an asset in the management of the primary and permanent teeth in young children. However, there is a need for further clinical and basic science research into the various aspects of the stainless steel crowns with the advancement of technology and techniques of conservative dentistry.

114References:Pediatric Dentistry: Infancy Through Adolescence. Pinkham. Fourth Edition.

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Kennedys Paediatric Operative Dentistry. Curzon, Roberts, Kennedy. edition.

Restorative Techniques in Pediatric Dentistry. Duggal, Curzon, Fayle, Pollard, Robertson. Second edition

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Stainless steel crown in clinical pedodontics: a review. F Salama. The Saudi Dental Journal, Volume 4, Number 2, May 1992

Efficacy of preformed metal crowns vs. Amalgam restorations in primary molars: a systematic review . Ros C. Randall. J Am Dent Assoc, vol 131, no 3, 337-343. 2000

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