STAINLESS STEEL

CROWN

Submitted by :Jaya NathaniSurabhi Nogariya

Department of PedodonticsGovt. College of Dentistry, indore

Contents Introduction Advantages Disadvantages Objectives Types Indications Contraindications Factors To be considered in pre operative evaluation Clinical Procedure Modifications Complications References

Introduction Stainless steel crown is semi permanent restoration used in primary and young permanent teeth

It was introduced as chrome-steel crown by ‘Humphrey’ in 1950.

Stainless steel crown is more frequently used in deciduous dentition than permanent dentition because of two reasons. 1. In deciduous teeth caries can destroy the tooth faster than permanent . 2. In deciduous tooth pulp is larger than permanent and enamel and dentin thickness is less.

• The crowns are far superior to multi surface amalgam restorations with respect to life span , replacement ,retention and resistance.

• They are acceptable to both patient and dentist.

• They are also more cost effective because of comparatively simple procedures involved in restoring severely affected primary molar.

Advantages

Disadvantage The aesthetics is not fair.

Objectives To achieve biologically compatible , competent for mastication and clinically acceptable restoration.

To maintain the form and function and where possible the vitality of the tooth should be maintained.

TypesUntrimmed 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

Pre-contoured crowns Festooned Pre-contoured A minimal amount of festooning and trimming may be necessary eg. Ni-Cr Ion crowns

According to composition stainless steel crowns are of two types

1.Austentic type•Best corrosion resistance•These crowns are available in various sizes.•Mostly these crowns are used in posterior teeth which undergone pulp therapy.

2.Nickel – base crownsThe alloys have good formability and ductility necessary for clinical adaptation of crowns and wear resistance to resist opposing occlusal forces.

Extensive decay in primary & young permanent teeth. For teeth deformed by developmental defects or

anomalies. For teeth with hypoplastic defects. Following pulp therapy. As preventive restoration. As an abutment. Temporary restoration of a fractured tooth. In severe cases of bruxism. For replacing prematurely lost anterior teeth Single tooth crossbite.

Indications

Contraindications If the primary molar is close to exfoliation with more than half the roots resorbed or exfoliation within 6-12 months

Clinical or radiological evidence of radicular pathology

Tooth exhibits excessive mobility

Partially erupted teeth

Where conservative restorations can be placed

In a patient with a known nickel allergy

1. Dental age of the patient. 2. Cooperation of the patient.3. Motivation of the parents. 4. Medically compromised/disabled child.

Factor to be considered in preoperative evaluation

Evaluate the preoperative occlusion• Evaluate the cast for the dental midline and the cusp fossa

relationship bilaterallySelection of crown 3 main considerations-• Mesiodistal diameter • Proper gingival contour• Proper occlusal height Tooth Preparation• LA should be administered Isolation• Using rubber dam and cotton rollsRemoval of decay

Clinical Procedure

Reduction Occlusal reductionA 69L or 169L bur is used to reduce the occlusal surface by 1.5-2.0mm .Proximal slicesplace the wooden wedges in the interproximal embrasures, the 69L or 169L bur is moved B-L across the proximal surface.Buccolingual reductionReduction is minimalRound off all the line angles It is done by using side of burInitial adaptation of crown The crown should be of correct length and margins should be adapted closely to the toothSeating the crown Crown is tried on preparation by seating lingual firstResistance should be felt as the crown slips over buccal bulge

Crown contouring Performed with a 114 plier in the middle 1/3rd of the crown to

produce a belling effect. This will give the crown a more even curvature.

Crown crimping Done with Unitek 800-412 pliers The tight marginal fit aids in:1. Mechanical retention of the crown.2. Maintenance of gingival health. 3. Protect of cement from exposure to oral fluids. Checking the final adaptation of the crown The crown should snaps securely into place. Occlusion should be checked

Finishing and polishingThe crown should be polished prior to cementation

with rubber wheel to remove all scratches.

Radiographic confirmation of the gingival fitBefore cementation a bitewing is taken to verify proximal marginal integrityCementationA zinc phosphate, polycarboxylate or GIC is preferred.

Result

In 1971, Mink & Hill report several way of modifying the SSC when they are either too large or too small

1. Undersize tooth or the oversize crown.2. Oversize tooth or undersize crown.3. Deep subgingival caries.4. Open contact.5. Open-faced stainless steel crown.

Stainless steel crown modifications

Interproximal ledge.Crown tilt.Poor margins.Inhalation or ingestion of crown.

Complications

Shobha Tandon, 2nd edition McDonald . Avery . Dean, 9th edition

References

Thank You