Prosthetics II. Fixed dentures nlay, root canal inlay Fixed dentures > Cemented (fixed) on/in pilots, abutment teeth. > Inlays (inlays, onlays, overlays, partial crowns). > Crowns > Bridges Fixed dentures Cemented on the teeth - crowns, bridges, inlays Fixed bridge lenka.roubalikova@tiscali.cz 5 Fixed dentures Material - metal alloy, ceramics lenka.roubalikova@tiscali.cz Removable dentures Partial Complete (fu lenka.roubalikova@tiscali.cz Procedures > In dental surgery > In dental laboratory > Special instruments > Basic (main) materials (metal alloys, ceramics,polymers) > Auxilliary (accessory) materials (impression, carving, die, insulating investing, grinding, polishing) lenka.roubalikova@tiscali.cz 9 Manufacturing of dentures Model of gypsum (plaster) - model of a denture (wax pattern). Model of a denture (wax pattern) directly in the mouth - rarely. Denture is formed without a wax pattern in the dental lab. lenka.roubalikova@tiscali.cz Manufacturing of dentures Model of gypsum (plaster) - model of a denture (wax pattern). lenka.roubalikova@tiscali.cz Impressions of the jaw - negativ The impression is filled with a casting material (gypsum) - poured into Model (various purpose) lenka.roubalikova@tiscali.cz 12 Models > Working model - the denture is produced on this model (special procedures) > Opposing model (antagonal) - necessary for the recognition of intermaxillary relationship > Bite regitration - wax lenka.roubalikova@tiscali.cz Manufactoring of dentures principle of lost wax method >The denture (not the denture itself but the model of the denture) is produced on the working model. >The model of the denture is made of the carving wax. >The wax is replaced by the main (base) material. lenka.roubalikova@tiscali.cz Fabrication of dentures The model (wax) of the denture is invested The wax is removed from the form and the base material is placed into the form. Wax removal: The wax is burned out (for metal alloys) or removed by hot water (for polymers) lenka.roubalikova@tiscali.cz 15 lenka.roubalikova@tiscali.cz 17 lenka.roubalikova@tiscali.cz 18 Manufacturing of dentures lenka.roubalikova@tiscali.cz 24 Manufacturing of dentures Direct method lenka.roubalikova@tiscali.cz Manufacturing of dentures Direct method No impression The model of the denture is made directly in the mouth For inlays only lenka.roubalikova@tiscali.cz Rigid fillings Manufactured in a dental lab Direct or indirect method Direct method rarely Indirect method most common ■ 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 tootlw stump, snag) Crown inlay Material > Composit > Ceramics > Metal Alloys r 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 Contra - indication Crown inlays 7. Too small - shallow (flat) cavities 2. High caries risk 3. Frontal area (metallic) Partial crown Retention of rigid fillings Whitstand capability aaainst axial forces: Geometry of the preparation Quality of the luting material (facilitating shape) Rau G. 1994 Retaining areal Surface of contact Inlay or crown (internal, outer, combined) Stability of rigid fillings Whitstand capability aqainst horizontal forces Angle of convergence Axial length contact surface Basic rules of cavity preparation >Box > No undercuts > Light divergence of the walls (facilitating shape) • ■ t3 Box Undercuts Simple box Facilitating form nlay of metal alloy Direct method Indirect method nlay of metal alloy > Direct method Direct modellation in the mouth Special wax - casting wax, (special polymers) Sprue pin Investment Method of the lost wax nlay of metal alloy Direct method > Central cavities (class I., classs V.) > Root canal inlays nlay 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 Btu0 ÍAUTlOHľ fUWUMWUE 7KIK -WW OIÉ fWf «5ntí«lS XFMdWBl Dokončená preparace Nasazená rekonstrukce Aesthetic inlays - composite materials, ceramics Special procedure Indirect method always Root canal filling Root Root canal inlay Core Crown Indication : Root canal inlay 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 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 Model Modellation - casting wax, heated, flowing Sprue pin Investment Lost wax method (burntout in the special oven) Indirect method Impression material Model Insulation Model lation / Indirect method Impression Model Modellation - casting wax, heated, flowing Sprue pin Investment Method of the lost wax (burntout in the special oven) lenka.roubalikova@tiscali.cz 72 Cementation Zinkoxid phosphate cement Lentulo Vaseline Removal of access of the cement