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The preparation of opposing cavity walls should be cut in a way to avoid undercuts in order to gain optimum retention from the cavity shape for the indirect restoration. [20] For inlay and onlay preparations that are going to be completed with all-ceramic then these cavity shapes can be slightly over-tapered as most of the retention is gained ...
Examples include all classes of cavity preparations for composite or amalgam as well as those for gold and porcelain inlays. Intracoronal preparations are also made as female recipients to receive the male components of removable partial dentures. Extracoronal preparations provide a core or base upon which restorative material will be placed to ...
The amalgam is mixed by the dentist just before use. It remains soft for a short while after mixing, which facilitates it being snugly packed into the cavity and shaped before it sets hard. Dental amalgams were first documented in a Tang dynasty medical text written by Su Gong (苏恭) in 659, and appeared in Germany in 1528.
In preparing a cavity for restoration with composite resin combined with an acid etch technique, all enamel cavosurface angles should be obtuse angles. Contraindications for composite include varnish and zinc oxide-eugenol. Composite resins for Class II restorations were not indicated because of excessive occlusal wear in the 1980s and early ...
As such, water equilibrium is reached within days rather than weeks, months or even years in the case of dental composite materials. This property has the advantage of compensating for the polymerisation shrinkage during the setting reaction, thus reducing any gap that develops at the cavity margins.
In Japan, the use of amalgam began to decline around the 1990s; since 2016, fillings with amalgam alloys have been excluded from insurance coverage. Amalgam is still allowed as of 2023, but is rarely used because it is very expensive. Dental composite and palladium alloys are used instead. [143]
No preparation of the buccal or lingual/palatal surfaces is required. [32] Stainless steel crowns can be made esthetic by veneering composite using the open face technique or composite veneering done after sand-blasting SSCs. Also, composite veneering can be done after preparing retentive grooves on the buccal surface of stainless steel crowns ...
The cavity preparation of a GIC filling is the same as a composite resin. GICs are chemically set via an acid-base reaction. Upon mixing of the material components, no light cure is needed to harden the material once placed in the cavity preparation. After the initial set, GICs still need time to fully set and harden.