Classification of the fillings Plastic Rigid Plastic fillings (they are soft when being placed into the cavity) • The material is soft, it is cured (set) in the cavity: amalgam, composite, glassionomer, temporaries. Rigid fillings - inlays • The material is rigid when being placed into the cavity Metal alloy, composite, ceramics. Inlays made of the metal alloy (usually precious alloys) • Rigid filling • Manufactured in a dental lab • Direct or indirect method - Direct method rarely (class I. only) - Indirect method (most cases) 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) 6 lroubalikova@gmail.com Root canal inlay – made of metal alloy (non precious) This inlay has two parts: root post core – coronal part. The core restore the crown only to the shape for later placement the prosthetic restoration e.g. ceramic crown. These inlays will be discussed next semester Post Core General indications for crown inlays: General indications for crown inlays: Big lost of hard dental tissues – when the restoration of the form and function with amalgam or composite is not possible. General contraindications o High risk of dental caries (inlay is a special treatment, when higher tendency to dental caries prosthetic treatment is bettter) o Small and shalow cavities o Frontal area Crown inlay Material Metal Alloys Composit Ceramics Inlay Advantages  Better anatomic form  Better polished Inlay Disadvantages  The technology is not easy  More time consuming  Expensive  Two appointments Basic rules of preparation Box  No undercuts  Light divergence of the walls (facilitating shape). Angle of divergency 6 – 15° Box No undercuts Simple box Facilitating shape Classification of inlays Inlay Classification of inlays Onlay Classification of inlays Overlay Metal inlay: sequence of operations Direct method Dental office - Preparation - Isolation of the cavity - Modellation of heated casting wax - Sprue pin – the thickest part,reservoir Dental lab - Investment - Casting (method of lost wax) -Finishing Dental office - Cementation Direct method is used in very rare cases, in the first class acc.to Black only Metal inlay: sequence of operations Indirect method Taking of the impression Model Modellation of the casting wax, (special polymers) Sprue pin Investment Lost wax method Taking impression using elastomeric materials – dual viscosity technique Antagonal impression and wax registration of the intermaxillary relationships are also taken Cementation • For inlays made of the metal alloy the zinkoxid cement is used. • It is mixed into the creamy consistency Non metallic inlays • Composite • Ceramics Preparation • Box • No undercuts • Facilitating shape – divergence of the walls appr. 6° • No bevel • Thickness of the material 1,5 – 2 mm Cavity for inlay made of composite or ceramics Preparation Tapered diamonds are used Indirect method Indirect method – with impression (see above) CAD CAM - the cavity is scanned on the model or in oral cavity. Taking impression using elastomeric materials – dual viscosity technique Antagonal impression and wax registration of the intermaxillary relationships are also taken lenka.roubalikova@tiscali.cz 33 Methods of fabrication Fabrication of these restorations is varioue because of many various materials and technologies. These technologies will not be discussed. Fabrication of the composite inlays Cementation  Adhesive materials – composite cements  Special materials requiring acid etching, priming and bonding  Chemically or dual curing low viscosity materials Cementation • Acid etching • Washing • Priming • Bonding • Application of the cement • Curing (during curing the border is covered with glycerin in order to avoid the inhibition layer – this is a superficial part of composite cement that is not completely cured due to oxygen in air) • Access removimng • Polishing Cementation using composite cements 38 Inlays on the model and in oral cavity