What are the types of special tray?
Types of special tra 1-spaced tray with wax(with or without stoppers) 2-closed fitted special tray without wax. 1-The cast should be soaked in water. 2-Severe undercuts should be blocked out using wax. 3-The borders of the special tray and the relief areas should be marked.
Why do we use special tray?
Advantages of special trays: 1- Economy in impression material ( used less impression material required in special tray). 2- More accurate impression. 3- Special tray provides even thickness of impression material. This minimize tissue displacement & dimensional changes of impression material.
What is special tray made of?
Custom trays are made up of auto-polymerizing Polymethyl-methacrylate (PMMA) resin, thermoplastic material and visible-light curing resin. The tray materials are supposed to be rigid, dimensionally stable, retentive to impression materials or adhesive and moisture resistant.
What is special tray?
An individualized impression tray made from a cast recovered from primary impression. It is used in making a final impression. Special tray is constructed on the primary cast.
Why spacer is used in dentistry?
Dental space maintainers (or spacers) are devices used for kids who have lost some baby teeth but their permanent teeth have a while before they will grow in. They hold space for the appropriate adult teeth to grow in. They also prevent the remaining adjacent baby teeth from moving into the open space.
What is spacer in prosthodontics?
T Shape Spacer: It is based on the Selective Pressure Technique. It covers the anterior residual alveolar ridge in the maxilla when it is flabby and resorbed. It also covers the prominent incisive papilla, rugae and midpalatine raphe, and the exposed areas act as stoppers.
What is the use of spacer in special tray?
Wax spacer fabrication for special trays used with rubber base impression materials. This technique grantee even thickness of impression materials, no pressure areas, controlled pressure from impression material on the mucosa and less amount of impression used.
Why spacer is used in special tray?
Wax spacer is used to provide space for impression material. It’s thickness varies according to material like 0.5 mm for ZOE, 1.5 mm for impression plaster , 3 mm for silicone impression material. Tissue stopper helps in proper placement and stabilization of the tray as it’s in directly contact of the mucosa.
What is dental putty?
Dental impression material putty is used to make molds and casts that help creating dental models, braces and reconstructions.
What are types of impressions?
Final impressions material are supplied in three forms or viscosity. Light body-is the easiest-flowing material to flow. Regular body-is slightly thicker than the light body form. Heavy body –is the thickest of the three forms.
What is a special tray?
Special Tray A special tray is defined as, “A custom made device prepared for a particular patient which is used to carry, confine and control an impression material while making an impression’’. 5.
Why are special trays used in prosthodontics?
This may indicate the inadequacy of many primary impressions to record this part of the mouth. Special trays tended to be used in removable prosthodontics, with equal proportions being used in complete and partial denture cases. Custom trays were requested in only a small number of treatments involving fixed cases.
What are the different types of trays in dentistry?
According to the method of fabrication of trays: A. Stock trays: – Full arch trays – Sectional trays – Quadrant trays B. Custom trays or Special trays 7. 3. According to the teeth present /absent in mouth: a. Edentulous trays b. Dentulous trays 8. How can I identify between Dentulous and Edentulous trays?
What should the dentist consider when prescribing special trays?
The dentist should consider the following key aspects of design when prescribing special trays in a given clinical situation: The position, number and form of any handles. Table 1 summarises a series of guidelines that may be followed in the use of custom impression trays in prosthodontics. These guidelines will now be considered in more detail: