BS EN ISO 3107:2011 pdf download
BS EN ISO 3107:2011 pdf download.Dentistry —Zinc oxide/eugenolcements and zinc oxidelnon-eugenol cements (Iso3107:2011).
7.2.1.5 Flat glass plate, approximately 1 mm thick (for example, a microsoopc slide).
7.2.2 Procedure
Condition the metal block (7.2.1.4) and rdenter needle (7.2.1.2) in the cabinet (7.2.1.1) at(37 ± 1) C.
Place the metal mould (7.21.3), conditioned at (23 ± 1) C. on the flat glass plate (7.2.15) and 1911 to a level surface with the cement,
After (60± 10)s from the start of mixIng for all cements, place the specimen, mould and glass plate on to the metal block.
305 before the setting time given by the manufacturer, carefully lower the indenter needle vertically on to the surface of the cement. Make indentations at 15s intervals with no superimposition of indentations until the setting time has been reached, Maintain the needle tip ii a clean condition between indentations
Record the setting time, to the nearest 15s, as the period of time which elapses from the start of mixing to the time when the needle fails to penetrate completely the 2 mm depth of cement.
7.2.3 Treatment of results
The result shall either be one 01 the limit values or lie between tile bmits given In Table 1
7.3 Determination of compressive strength
7.3.1 Apparatus
7.3.1.1 Split moulds and plates, for example as shown In Figure 2. suItable for the preparation of a cylindncal specimen with a height of 6 mm and a diameter of 4 mm, and made of a material that is neither attacked nor corroded by the cement, such as stainless steel.
7.3.1.3 CabInet, as specified in 7.2.1.1.
7.3.1.4 Micrometer or similar measuring device, accurate to 1 pm.
7.3.1.5 MechanIcal tester, capable of being operated at a crosshead speed of (0.75 ± 0.30) mm/mm or at a loading rate of (50 ± 16) N/mm.
7.3.2 Preparation of test specimens
Condition the moulds (7.3.1.1), screw damps (7.3.1.2) and top and bottom plates (7.3.1 .1) at (23 ± 1) °C.
After mixing In accordance with the manufacturer’s Instructions, pack the cement, to a slight excess. Into the split moulds within I mm of the completion of mixing. In oder to consolidate the cement and to avoid trapping air, it is advisable to convey the largest convenient portions 01 mixed cement to the mould and apply to one side with a suitable instrument. Fil the mould to excess in this manner and then place the mould on the bottom plate and pack the cement, such that the excess is expressed.
To facilitate the removal of the hardened cement specimen, the internal surface of the mould may be evenly coated, prior to filling, with a 3 % solution of micro-crystalline or paraffin wax in pure toluene. Alternatively, a thin film of silicone grease ci’ potytetrafluoroethylene (PTFE) dry film Iubiicant may be used.
Remove any extruded cement, place the top metal plate in position and squeeze together. Put the mould and plates i the clamp (7.3.1.2) and screw tightly together. Not later than 2 mm after completion of nixing. transfer the whole assembly to the cabinet (7.3.1.3), maintained at(37 ± 1) C.
One hour after completion of mixing, remove the plates, and prepare the surface of the ends of the spedmen plane, at right angles to its long axis, using a small amount 0145 pm silicon carbide powder or similar abrasive. mixed with water (ISO 3696. grade 2) on a flat glass plate. Keep the specimen wet during preparation.
Alternatively, use en equivalent grade of abrasive coated paper and water (ISO 3696. grade 2). Keep the ends of the specimen flat by rotating the specimen one quarter turn every few strokes.
Remove the specimen troni the mould immediately after surfacing and examine for air voids or chipped edges. Discard any specimens with these detects.
Immerse each specimen Ii distilled or deionized water (ISO 3696, grade 2) and maintain at (37 ± 1) C for 24 h, after which condition in distilled or deionized water at (23± 1) C for (15 ± 1)min prior to testing. Then. measure the diameter of the cylinder with the micrometer (7.3.14) to the nearest micrometre, Proceed immediately to testing. The testing procedure requires five specimens.
7.3.3 Procedure
Immediately after the end of the conditioning period, place the specimen with the flat ends between the platens of the mechanical testing apparatus (7.3.1.5) so that the load is applied in the long axis 01 the specimen. Use a cross head speed of (0,75 ± 0.30) mm/mm or a loading rate of (50 ± 16) N/mm until fracture. Record the maximum force applied when the specimen fractures.
Test five specimens.
