CONTENTS Types of crown

Different type of Stainless Steel Crown

Objective of Using

Advantage

Disadvantage

Composition

Indication

Factor s to be considered in Pre-Operative Evaluation

Clinical Procedure

Tooth Preparation

Steps in Reduction

Initial Adaptation of Crown

Seating the Crown

Crown Contouring

Crown Crimmping

Checking Final Adaptation of Crown

Finishing and Polishing

Radiographic Confirmation of Gingival Pit

Cementation

Result

Confirm Occlusion

Stainless Steel Crown Modifications

Complications

Reference

INTRODUCTION

Stainless steel crown is a 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 .

Stainless steel crown is an efficient and reliable

method of restoration of deciduous dentition.

TYPES OF CROWN

•Stainless steel

•Nickel chromium

•Veneered stainless steel crowns

•Strip crown (ZIRCONIA)

•Ceramic crown

DIFFERENT TYPES OF STAINLESS STEEL CROWN

1) Untrimmed - These crowns are neither trimmed nor contoured thus require lot of adaptation and are time consuming.

Eg :- Rocky Mountain.

2) Pretrimmed - These crowns have straight non-contoured sides but are festooned to line parallel to the gingival crest. They

still require contouring and trimming.

Eg : - Unitek Stainless steel Crowns and 3M Co.

3) Precontoured - These crowns are festooned and are also precontoured though a minimal amount of festooning and trimming

may be necessary. Eg : - Unitek Stainless steel Crowns and 3M Co.

Untrimmed : Neither trimmed nor contoured

Pretrimmed : Crowns have straight non-contoured sides.

Precontoured : Crowns are festooned

DIFFERENT TYPES OF STAINLESS STEEL CROWN

OBJECTIVES OF USING

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.

ADVANTAGES

These crowns are more superior to multisurface amalgam

restoration with respect to life span, replacement , retention and

resistance.

They are acceptable to both patient and dentist

They are more cost effective because of comparatively simple

procedure involved in restoring even severely affected primary

molars

DISADVANTAGE

The aesthetics is not fair

COMPOSITIONSTAINLESS STEEL CROWN

•17-19% - chromium

•10-13% - nickel

•67% - iron

•4% - minor elements

NICKEL-BASE CROWN

•72% - nickel

•14% - chromium

•6-10% - iron

•0.04% - carbon

•0.35% - manganese

•0.2% - silicon

INDICATIONS

Extensive decay in primary and young permanent tooth

Teeth deformed by developemental defects or anomalies

Teeth with hyperplastic defects

Following plup therapy

As a preventive restoration

As an abutment

Temporary restoration of

a fractured tooth

In severe cases of bruxism

Single tooth cross bite

For replacing prematurely lost anterior teeth

FACTORS TO BE CONSIDERED IN PRE-OPERATIVE

EVALUATION

Dental age of the patient

Co-operation of the patient

Motivation of the patient

Medically compromised/disabled children

CLINICAL PROCEDURE

EVALUATE THE PREOPERATIVE OCCLUSION

•Take the alginate impression of U/L jaws.

•Pour the cast with dental stone

•Note the dental midline and the cusp fossa

relationship bilaterally

SELECTION OF CROWN

•The correct size crown is selected by the M-D

dimensions of the tooth to be restored using Boley

gauge.

•To produce steel crown margins of similar shape

examine the contour of gingiva of the buccal & lingual

marginal gingiva.

TOOTH PREPARATION•L.A. should be administrated

•Isolation by rubber dam or cotton rolls

•Remove the decay

STEPS IN REDUCTIONOCCLUSAL REDUCTION

A 69L or 169L bur is used to reduce the occlusal surface by

1.5-2.0mm .

PROXIMAL SLICES

Place the wooden wedges in the inter proximal embrasures, the 69L bur

is moved B-L across the proximal surface.

BUCCOLINGUAL REDUCTIONReduction of buccal and lingual surface is minimal

ROUND OFF ALL THE LINE ANGLES It is done by using side of bur

INITIAL ADAPTATION OF CROWN

•The crown should be of a correct length and its margins

should be adapted closely to the tooth.

•For shaping the crown margins mark 3 light points on the

metal at the (mesiolingual, lingual and distolingual)and at

(mesiobuccal, buccal, distobuccal) surfaces at the crest of

respective marginal gingiva without compressing the

marginal gingiva.

•Final finished margins are placed approximately 1mm

below these marks.

SEATING THE CROWN

Now the crown is tried on the preparation 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.

CROWN CONTOURING•Initial crown contouring is performed with a114 plier (ball and

socket plier) in the middle 1/3rd of the crown to produce belling

effect

•This will give the crown more even curvature

CROWN CRIMPING•This is very important to the gingival Health of the

supporting tissue.

•Using the no.417 crimping pliers the crown is crimped

in the gingival third.

•After completion of crimping there

will be gradual bend in the gingival

third of crown.

•The use of crimping is for the

protection of soft Tissues.

CHECKING THE FINAL ADAPTATION OF THE CROWN

The crown should be replaced on the preparation after

the contouring procedure to see that it snaps securely into

place.

The occlusion should be checked at this stage to make

sure that the crown is not opening the bite or causing a

shifting of mandible into an undesirable relationship with

opposing teeth.

FINISHING AND POLISHING

Accumulation of plaque and inflammation of

gingiva is commonly seen in practice of restorative

dentistry due to rough and unpolished restoration.

To avoid these complications crown should be

polished prior t o cementation with rubber wheel to

remove all scratches.

RADIOGRAPHIC CONFIRMATION OF THE GINGIVAL FIT

Before cementation a bitewing is taken to

verify proximal marginal integrity

CEMENTATIONSSC should be cemented

only on clean dry mouth, isolation of teeth with cotton roll

is recommended.

Rinse and dry the crown inside & out side and prepare to

cement it.

A zinc phosphate, polycarboxylate or GIC is preferred.

Before the cements set ask the patient to close into

centric occlusion by applying pressure through a

cotton roll and confirm that the occlusion has not been

altered.

Remove the excess cement by an explorer or scaler & for

interproximal area can be cleaned by passing dental floss

through them.

RESULT

CONFIRM OCCLUSION

STAINLESS STEEL CROWN MODIFICATIONS

In 1971, Mink & Hill report several way of modifying the stainless steel crown when they

are either too large or too small

• Undersize tooth or the oversize crown.

• Oversize tooth or undersize crown.

• Deep subgingival caries.

• Open contact.

• Open-faced stainless steel crown.

COMPLICATIONS

• Interproximal ledge.

• Crown tilt.

• Poor margins.

• Inhalation or ingestion of crown

REFERENCE

•Shobha Tondon