Bite registration material
Bite registration is an extremely important step in the fabrication of diagnostic models, restorations, bite-raising appliances, orthodontic appliances etc. It is used for precise, clear indexing of the three-dimensional alignment of maxilla and mandible in the required relationship.
In addition to increasingly popular, yet technically still very costly primary digital (virtual) procedures, analogue registration methods are still mainly used today. Reversible thermoplastic (wax, resin, gutta percha), chemically-curing (ZnO, acrylics) and irreversible elastic (e.g. PVS = polyvinyl siloxane) bite registration materials are generally available for analogue registrations. These are applied either directly on natural or prosthetic opposing teeth or used for the fixation/indexing of custom-fabricated bite blocks, in full and partial denture prosthetics, for example in the form of an acrylic base (previously also shellac) with wax bite rims attached or as a connection between the upper and lower plates (acrylic, metal) in Gothic arch registration.
Zink oxide bite registration material
Silicone bite registration (check)
Addition-curing silicone bite registration materials (A-silicones), which are closely related to impression materials, offer the advantages of flowability (low bite resistance, avoids bite displacement) and positional stability (no uncontrolled flow) due to thixotropy, detailed representation (crisp details), dimensional stability (withdrawal from undercuts), thermal stability, good processability (grinding and/or trimming) and insensitivity to moisture or mechanical stress (compressive, tensile) after curing. Colour, transparency or opacity, setting time and final hardness (Shore A to Shore D), and scannability can be modified to a wide extent, depending on the area of application. They are used mainly as two-component bite registration materials (base + catalyst/activator) in standardised cartridges, which are mixed and applied using mixing guns and mixing tips.