YY 0493-2011Dentistry—Elastomeric impression materials (English PDF)

3.1 consistency

degree of firmness with which particles of a material, prepared for use, cohere so as to allow the material to flow, or resist flow, as required to achieve the purpose for which it is intended

3.2 elastic recovery test

(elastic impression materials) method of determining whether the materials possess the elastic properties required to recover adequately after deformation occurring when the materials, used for forming impressions, are removed from the mouth

Note: The terms "compression set", "permanent deformation", and "recovery from deformation" are deprecated here.

3.3 extrusion mixing

method by which two or more material components are extruded from their separate immediate containers through a special mixing tip, from which the components emerge as a homogeneous mixture

3.4 hand mixing

method of mixing the components of a material by means of manual kneading or spatulation

3.5 immediate container

container which is in direct contact with a material or a component thereof

Note: An immediate container may be an unlabelled container protected by a more durable labelled outer package component such as a can, carton or drum. If it is strong enough to protect its contents without outer package, an immediate container can also serve as a primary container on which labelling shall be required.

3.6 mixing time

time, measured from first contact between different components of a material being mixed, required to achieve a homogeneous mixture when the components are mixed according to the manufacturer’s instructions

Note: The time of first contact between extrusion-mixed material components is defined as the time when the material components can be seen entering into the mixing nozzle.

3.7 outer package

wrapping or carton, which may be required by law or a standard to bear specified labelling, used to cover one or more immediate or primary containers in preparation for retail marketing

3.8 primary container

retail marketing packaging component, such as a bottle, carton, drum, jar, and tube, which may be required by law or a standard to bear specified labelling

Note: A primary container may also be an immediate container.

3.9 strain-in-compression test

(elastic impression materials) method of measuring the flexibility/stiffness property ranges of materials so as to determine whether the set materials, when formed as impressions a) can be removed from the mouth without injury to impressed oral tissues, and b) will have adequate stiffness, in the more flexible portions of impressions, to resist deformation when model-forming products are poured against them

3.10 working time

period of time, beginning with the commencement of mixing and ending before the material being mixed has begun to exhibit elastic properties that will prevent the material from being manipulated as required to form an impression or a mould having the desired surface detail and dimensional characteristics

6.1 Component colours

Different components intended for use in the same mixture shall be supplied in contrasting colours to provide a means of determining when the components have been thoroughly mixed.