BS EN ISO 1559:2001 pdf – Dental materials — Alloys for dental amalgam

BS EN ISO 1559:2001 pdf – Dental materials — Alloys for dental amalgam.
1 Scope This International Standard specifies requirements and test methods for alloys composed mainly of sil- ver, tin and copper, complying with the composition requirements (see 4.1). The alloy may be in either powder or tablet form, or in capsules with portions of alloy and mercury predosed by the manifacturer, suitable for the preparation of dental amalgam. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the standards indicated below. Mermbers of IEC and ISO maintain registers of cur- rently valid International Standards. ISO 78 4:1983，Layouts for standards Part 4: Standard for atomic absorption spectrometric analysis. ISO 286-2:1988， ISO system of limits and fits – Part 2: Tables of standard tolerance grades and limit deviations for holes and shafts. ISO 468:1982，Surface roughness – Parameters, their values and general rules for specifying require- ments. ISO 1560:1985, Dental mercury.
4.3 Mass The coefficient of Variation of the mass of alloy tablets shall not exceed 1,5 % (m/m) and the arithmetic mean of the mass of alloy tablets shall be within + 2 % (m/m) of the manufacturer’s stated mass when tested in accordance with 6.5. For capsules containing preproportioned alloy and mercury, the coefficients of Variation of the masses of the alloy and the mercury shall each not exceed 1,5 % (m/m) and the arithmetic means of the masses of both the alloy and the mercury shall each be within + 2 % (m/m) of the manufacturer’s stated masses when tested in accordance with 6.5. 4.4 Loss of mercury Capsules predosed with alloy and mercury by the manufacturer shall meet the following requirements: – the mercury in capsules shall comply with ISO 1560; – the loss in mass for each capsule during amal- gamation shall not exceed 0,5 mg when tested according to 6.6.
6.1 Preparation of test specimens 6.1.1 Temperature Prepare all test specimens at (23 + 2)。C. 6.1.2 Amalgamation The mass of the amalgarm mix shall be sufficient to make a test cylinder (8 土1) mm high after conden- sation with a diameter according to figure 1. If necessary, adjust the height of the cylinder by con- densing only a portion of the amalgam mix into the mould. For alloy supplied as tablets or powder, the alloy mass and the mercury mass to be mixed, the capsule (if needed), the pestle (if needed), and any other mixing accessories required shall conform to those recommended by the manufacturer in accord- ance with 7.3.1 and 7.3.2. For capsulated alloy and mercury, simultaneously amalgamate as many cap- sules as needed. An amalgamator that complies with ISO 7488 shall be used. The amalgamator’s frequency (or machine setting) and the amalgamation time shall be as specified by the manufacturer in accordance with 7.3.2.
6.1.3 Apparatus for preparation of test specimens for determination of creep, dimensional Change and compressive strength Use an all-mechanical apparatus as shown in figure 1. The holder, spacers and cap need not be hardened; they shall be made of cold-rolled or stainless steel. Make the die and plungers of hardened tool steel or hardened stainless steel. Hone the working surfaces of the die and plungers to a surface roughness value (y,) of not greater than 6,3 Pm when tested in ac- cordante with ISO 468. Limits of clearance between the die and plungers shall be F7/h7 in accordance with ISO 286-2. Assemble the holder, spacers Nos. 1 and 2, the die and plunger No. 2 as shown in figure 1. Position the cap shown in figure 1 on top of plunger No. 2 when dimensional Change specimens are being made. 1 glass plate may be used instead of a cap. 6.1.4 Condensation Empty the coherent mass of amalgamated materia on top of the cavity of the die and immediately inser t the amalgam into the mould with several thrusts of an amalgam condenser slightly less than 4 mm in di- ameter. DO not express mercury during insertion. When preparing specimens for dimensional Change tests, insert the other cap (shown in figure 1) with the flat surface up. Insert plunger No. 1 and follow the time schedule in table3. The specimen shall not be trimmed. After ejection, transfer the specimen to an environment maintained at (37 ~fr 1) “C.