STAINLESS STEEL STAINLESS STEEL CROWNSCROWNS

INDICATIONSINDICATIONS1. Extensive Decay: 3 / more surfaces.2. Following Pulp Therapy: Brittle/ Loss of tooth

structure3. Preventive restoration: Avoids amalgam # prevents caries Handicapped Plaque easily visualized4. Hypoplastic defects

5. Abutment for space maintainers

CLASSIFICATIONCLASSIFICATION

1. MANUFACTURER: Unitek/3M/ Rocky Mountain

2. COMPOSITION: 18:8 Stainless Steel/ Ni-Cr

3.UNTRIMMED / PRETRIMMED /PRECONTOURED

4.Anterior/Posterior

CompositionComposition

STAINLESS STEEL CROWNS

•AUSTENITIC / MARTENSITIC /FERRITIC

•AUSTENITIC: High Ductility/ Yield Strength/ Ultimate Tensile Strength/ Corrosion Resistance./ Work Hardened

•18% Cr, 8% Ni, C- 0.05%- 0.15%, Fe- 70%

Ni-Cr CROWNS

•Ni-72%,Cr-16%,Fe-10%, C/ Mn /Si- 2%.

•Easy to fit, Least amount of trimming, crimping, contouring.

•Strain Hardened during the manufacture.

EQUIPMENTEQUIPMENT

1.BURS: Flame shaped bur,1/2 round bur, 4/6 round bur, Green Stone

2 Pliers: Johnson No 114 Gordon No 137 N0 417 Abell ball & socket Crown & Bridge Scissors

3.Rubber dam,Wedges, Glass slab & CEMENT

PROCEDUREPROCEDURE

CROWN SELECTIONCROWN SELECTION: Fit smallest crown : Fit smallest crown possiblepossible

Pre-op: matching the MD widthPre-op: matching the MD width

Trial & Error Trial & Error

Evaluate Evaluate : occlusion, dental midline, cusp : occlusion, dental midline, cusp fossa relationship, primate spaces.fossa relationship, primate spaces.

LA, Rubberdam ,WedgingLA, Rubberdam ,Wedging

TOOTH PREPARATIONTOOTH PREPARATION

Occlusal ReductionOcclusal Reduction : 1.5-2 mm, remove : 1.5-2 mm, remove caries.caries.

Proximal reductionProximal reduction: Contacts : Contacts broken,slight occlusal convergence. broken,slight occlusal convergence. Feather edge finish lineFeather edge finish line

Buccal & Li reductionBuccal & Li reduction : Minimal reduction, : Minimal reduction, Bu/Li cervical bulge can be left uncutBu/Li cervical bulge can be left uncut

Finishing:Finishing: All line angles rounded All line angles rounded Evaluate Evaluate PreparationPreparation

PROXIMAL REDUCTION

BUCCAL & LINGUAL BUCCAL & LINGUAL REDUCTIONREDUCTION

CROWN SEATED

TRIAL FITTING,TRIMMING & CONTOURINGTRIAL FITTING,TRIMMING & CONTOURING

Aim:Aim: leave margins in gingival sulcus leave margins in gingival sulcus (1mm) & reproduce crown morphology(1mm) & reproduce crown morphology

Seating crownSeating crown::Gingival marginGingival margin: marked & trimmed with : marked & trimmed with

scissorsscissorsContoured & CrimpedContoured & CrimpedFinal smoothening & PolishingFinal smoothening & Polishing: heatless : heatless

stone, rubber wheel.stone, rubber wheel.Evaluate adaptation of crownEvaluate adaptation of crown

Evaluation of initial adaptationEvaluation of initial adaptation

SnapSnap into place into placeSnugly fit against preparationSnugly fit against preparationMargins extend 1mm below gingivaMargins extend 1mm below gingivaNo blanchingNo blanchingRestore occlusionRestore occlusion

CementationCementation

Post cementation instructionsPost cementation instructions

PRINCIPLES FOR OBTAINING OPTIMAL ADAPTATION

ADAPTING OVERSIZED CROWN

ADAPTING SMALLER CROWN

TEETH WITH SUBGINGIVAL CARIES

Placement of adjacent crownsPlacement of adjacent crowns

• Occlusal reduction of one crown Occlusal reduction of one crown completelycompletely

• Proper proximal reductionProper proximal reduction• Both crowns trimmed, contoured & Both crowns trimmed, contoured &

prepared for cementation simultaneouslyprepared for cementation simultaneously• Placement & Cementation of most distal Placement & Cementation of most distal

tooth first.tooth first.

SSC & CL2 AFSSC & CL2 AF

Do tooth preparation & Cl2 cavity Do tooth preparation & Cl2 cavity preparation.preparation.

Cement crownCement crownAdapt wedge & matrix & insert amalgamAdapt wedge & matrix & insert amalgam

SSC in Space LossSSC in Space Loss

Tooth preparation for smaller crownsTooth preparation for smaller crownsUsually crowns will fit individually but Usually crowns will fit individually but

not at the same timenot at the same timeBy experimentation select the optimum By experimentation select the optimum

combination of crownscombination of crownsFlatten contacts with Howe plierFlatten contacts with Howe plierAlign the marginal ridges properly using Align the marginal ridges properly using

Howe plierHowe plier

Complications