Prosthetics II.
Fixed dentures Inlay, root canal inlay
Fixed dentures
> Cemented (fixed) on/in pilots, abutment teeth.
> Inlays (inlays, onlays, overlays, partial crowns).
> Crowns
> Bridges
Inlays
■ Rigid fillings
■ Manufactured in a dental lab
■ Direct or indirect method
- Direct method rarely
- Indirect method most common
Inlay
■ Crown inlay
- a part of a clinical crown is replaced
■ Root canal inlay
- The inlay is cemented into the root canal and replaces a crown (abutment tooth -stump, snag)
Crown inlay
Material
> Composit
> Ceramics
> Metal Alloys
Angle of convergence
>0° - maximum > 6° - very good >15°- acceptable >20° - insuficient
Optimum 6° -15°.
Crown inlays
Indikations
• A big lost of dental tissues
• Big interdental spaces
• Next to the crowns and bridges made of metal alloy
Crown inlays
Contra - indication
1. Too small - shallow (flat) cavities
2. High caries risk
3. Frontal area (metallic)
Crown
Retention of rigid fillings
Whitstand capability aaainst axial forces:
Geometry of the preparation (facilitating shape)
Quality of the luting material
Retaining areál
■ Surface of contact Rigid filling
Inlay or crown (internal, outer, combined)
Stability of rigid fillings
Whitstand caoabilitv aaainst horizontal
forces
Angle of convergence Axial length contact surface
Basic rules of cavity preparation
>Box
> No undercuts
> Light divergence of the walls (facilitating shape)
Box
Undercuts
Simple box Facilitating form
Inlay of metal alloy
■ Direct method
■ Indirect method
Inlay of metal alloy
> Direct method
Direct modellation in the mouth Special wax - casting wax, (special polymers) Sprue pin Investment
Method of the lost wax
Inlay of metal alloy
Direct method
> Central cavities (class I., classs V.)
> Root canal inlays
Inlay of metal alloy
Indirect method
Taking of the impression Model
Modellation of the casting wax, (special polymers) Sprue pin Investment
Method of the lost wax
Aesthetic inlays - composite materials, ceramics
Special procedure
Indirect method always
Root canal inlay
Root canal inlay
Indication :
Restoration for teeth with lost crown
(cca 2/3 of the crown)
It is anchored in the root canal
(the tooth must be endodontically treated)
The coronal part is formed as a stump for the crown
It enables to treat this teeth with crown
Contraindication
■ Teeth that cannot be treated endodontically
■ Decay of the root or coronal part of the crown
■ Less than 1 mm hard dental tissues supragingivally
■ Destruction of root canal walls circulary
Root canal inlay - preparation
■ Removal of the root canal filling (2/3), 4 mm of the root canal filling must be left.
■ The third rule
Preparation
f 4mm at least
Direct method
Isolation
Modellation - casting wax, heated, flowing
Sprue pin with reservoir Sprue cone Investment Lost wax method
(burntout in the special oven)
Indirect method
Impression
Impression material
Impression tray
Indirect method
Impression
Modellation - casting wax, heated, flowing
Sprue pin Investment
Method of the lost wax
(burntout in the special oven)
aste
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Final product
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Cementation
■ Zinkoxid phosphate cement
■ Lentulo
■ Vaseline
■ Removal of access of the cement