SIST EN 24823:2000
(Main)Dental elastomeric impression materials (ISO 4823:1992)
Dental elastomeric impression materials (ISO 4823:1992)
Zahnärztliche elastomere Abformmassen (ISO 4823:1992)
In der vorliegenden Norm werden die Anforderungen an die elastomeren Abformmassen festgelegt, die aus einer Basis von z.B. Polysulfiden, Polysiloxanen oder anderen nichtwässrigen Stoffen bestehen und die so reagieren, dass sie eine gummiähnliche, für Abdrücke geeignete Masse bilden.
Produits dentaires pour empreintes, a base d'élastomeres (ISO 4823:1992)
Dental elastomeric impression materials (ISO 4823:1992)
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Dental elastomeric impression materials (ISO 4823:1992)Zahnärztliche elastomere Abformmassen (ISO 4823:1992)Produits dentaires pour empreintes, a base d'élastomeres (ISO 4823:1992)Dental elastomeric impression materials (ISO 4823:1992)11.060.10Dental materialsICS:Ta slovenski standard je istoveten z:EN 24823:1993SIST EN 24823:2000en01-januar-2000SIST EN 24823:2000SLOVENSKI
STANDARD
SIST EN 24823:2000
SIST EN 24823:2000
SIST EN 24823:2000
INTERNATIONAL STANDARD IS0 4823 Second edition 1992-03-l 5 Dental elastomeric impression materials Produits dentaires pour- empreintes, ii base d%lastom&es Reference number IS0 4823: 19921 E) SIST EN 24823:2000
IS0 4823:1992(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 4823 was prepared by Technical Committee ISO/TC 106, Dentistry, Sub-Committee SC 2, Prosthodontic materials. This second edition cancels and replaces the first edition (IS0 4823:1984), of which it constitutes a technical revision. This revision of IS0 4823 differs from the first edition in the following respects: . a) The system of classification into categories, based upon two different physical properties, has been deleted by reason of simplification. The classification is now based on types only and completed with the introduction of type 0 - very high consistency. b) The physical property ?ompression set” is changed to “recovery after deformation” with the consequence that the value is between 96,s % and 100 %. c) For the physical requirement “strain in compression” a lowest limit of 0,8 % is now permitted. d) A special requirement for “gas evolution” is deleted, as it is inherent to the test about compatibility with gypsum when it is stated whether the lines are completely reproduced over the full length. 0 IS0 1992 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission In writing from the publisher. International Organization for Standardization Case Postale 56 l CH-1211 Genkve 20 * Switzerland Printed in Switzerland ii SIST EN 24823:2000
IS0 4823:1992(E) Introduction Specific qualitative and quantitative requirements for freedom from bio- logical hazard are not included in this International Standard, but it is recommended that, in assessing possible biological or toxicological hazard, reference should be made to the appropriate clauses of ISWTR 7405:1984, Biological evaluation of denfaI materials, or any more recent edition. . . . III SIST EN 24823:2000
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INTERNATIONAL STANDARD IS0 4823:1992(E) Dental elastomeric impression materials 1 Scope This International Standard specifies requirements for elastomeric impression materials based, for ex- ample, on polysulfides, polysiloxane or other non- aqueous materials capable of reacting to form a rubber-like material suitable for taking impressions. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encour- aged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of cur- rently valid International Standards. IS0 6873:1983, Dental gypsum products. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3,l mixing time: That part of the total working time starting at the commencement of mixing required to obtain a homogeneous mix of the components of the material. 3.2 total working time: Period of time between the start of mixing and the commencement of the de- velopment of elasticity and the loss of plasticity. 4 Classification The impression materials described in this Inter- national Standard shall be classified into types ac- cording to their consistency (see 5.3), determined in accordance with 7.3 (after mixing but before setting). Type 0: very high consistency - putty Type 1: high consistency - heavy bodied Type 2: medium consistency - medium bodied Type 3: low consistency - light bodied 5 Requirements 5.1 Components All components shall be supplied in contrasting col- ours to provide a means of indicating when a uni- form streak-free mix is achieved. Components, if supplied in a tube, shall not show gross separation and shall be capable of being extruded by hand pressure at normal room tem- perature (18 “C to 25 “C). When tubes are used they shall not rupture during extrusion of the com- ponents. The crimped end of the tube shall be sealed so that no leakage can occur. Testing shall be carried out in accordance with 7.2 5.2 Biocompatibility See the Introduction for guidance on biocompati- bility. 5.3 Consistency 3.3 setting time: Period of time between the start of mixing and the development of the elasticity necessary for removal of the impression with the least amount of distortion. Diameters of the consistency test discs shall comply with requirements shown in table 1. Testing shall be carried out in accordance with 7.3. 1 SIST EN 24823:2000
IS0 4823:1992(E) 5.4 Mlxlng time The mixing time, within that stated by the manufac- turer [see 8.2e)], shall not exceed 60 s. 5.5 Mixed material When mixed according to the manufacturer’s in- structions, streak-free mixes shall be obtained. Testing shall be carried out in accordance with 7.2. 5.6 Total worklng time The total working time shall not be less than that stated by the manufacturer and shall be at least 30 s longer than the time required to obtain a streak-free mix. Testing shall be carried out in accordance with 7.4. 5.7 Setting time The setting time stated by the manufacturer shall be the time in which the material develops the recovery from deformation as stated in 5.9. Testing shall be carried out in accordance with 7.6. 5.8 Strain in compression The strain in compression shall comply with the re- quirements in table 1 for each type of material. Testing shall be carried out in accordance with 7.5. 5.9 Recovery from deformation The recovery from deformation shall be between 96,5 % and 100 %. Testing shall be carried out in accordance with 7.6. 5.10 Linear dimensional change The linear dimensional change after 24 h shall be within the range of 0 to 1,5 %. Testing shall be carried out in accordance with 7.7. 5.11 Detail reproduction The material shall reproduce a line according to at least the minimum requirements given in table 1. Testing shall be carried out in accordance with 7.8. 5.12 Compatibility with gypsum The material shall impart a smooth surface to, and shall separate cleanly from, the cast poured against the material. The cast shall reproduce for each type of material the line according to the requirements of table 1. The reproduction shall be considered to be satisfactory if the respective line (a, b or c) is continuous be- tween the d-lines (see figure7). Testing shall be carried out in accordance with 7.9. Table 1 - Physical requirements Type Consistency, disc diameter Strain in compression Detail repro- duction, line width mm % mm Com- patibility with gY psum, line width mm 0 1 2 3 35 max?) 0,8 to 20 0,075 0,075 32 max. 0,8 to 20 0,050 0,050 31 to 39 2 to 20 0,020 0,020 36 min. 2 to 20 0,020 0,020 1) Mixed in the hands. 6 Sampling The test samples shall consist of a retail package or packages of materials from the same batch. 7 Test methods 7.1 General Unless otherwise specified, all tests shall be con- ducted in an environment having a temperature of (23 5 2) “C and a relative humidity of (50 + 10) %. All materials and test equipment shall be brought to temperature equilibrium in this environment before testing. 7.2 Visual inspection Compliance with the requirements laid down in 5.1, 5.5, 5.11, 5.12, and clauses 8 and 10 shall be checked visually, if appropriate with magnification. 7.3 Consistency 7.3.1 Apparatus 7,3.1.1 Load of (1 500 + 2) g mass, mounted in a loading device, such asihat shown in figure 1 or 3, in such a manner as to allow essentially frictionless movement in a vertical direction. 7.3.1.2 Two glass plates approximately 60 mm by 60 mm each with a mass of (20 + 2) g. 2 SIST EN 24823:2000
IS0 4823:1992(E) 7.3.1.3 Delivery device of a suitable design and material, for example glass or polytetra- fluoroethylene (PTFE) tube, having an internal di- ameter of approximately 10 mm and designed to deliver (0,5 k 0,OZ) ml by means of a plunger. 7.3.1.4 Discs or sheet of polyethylene or other suitable material IO mm in diameter and approxi- mately 0,035 mm thick for covering the plunger head each time it is used. 7.32 Procedure Dispense 0,5 ml of the paste, mixed according to the manufacturer’s instructions and with the shortest mixing time stated, by means of the delivery device onto the centre of one of the glass plates. (The polyethylene disc will be delivered with the paste.) Centre and gently lower the second glass plate over the first and place the 1 500 g load on top 30 s after the end of the mixing. During the test procedure, ensure that the glass plates are maintained parallel to each other and that no rotational movement takes place. After 5 s remove the load. After allowing the ma- terial to set, measure the diameter of the disc to the nearest 0,5 mm across two diameters at right angles to each other. 7.3.3 Expression of results Carry out the procedure three times and record the average of the six determinations to the nearest millimetre. 7.4 Total working time 7.4.1 Apparatus 7.4.1.1 Tray, as shown in figure2, having a flat and smooth internal surface. Six compartments may be added if desired. 7.4.1.2 Twelve circular solvent-resistant plastic discs at least 5 mm thick, each disc having flat sur- faces parallel within 0,Ol mm. Six of these discs shall be (16 + 0,2) mm and the other six shall be (IO + 0,l) mm in diameter. - 7.4.1.3 Loading device, as shown in figure 3, that allows essentially frictionless movement in the ver- tical direction. Two movable columns are required, one with a mass of 30 g and another with a mass of 325 g. The columns shall end in a platen with a diameter 1 mm smaller than the discs used and parallel to the base of the instrument. Provision shall be made for the attachment of weights to increase the mass of the movable column to 500 g and 2 000 g. 7.4.1.4 Dial gauge, accurate to 0,Ol mm, mounted perpendicularly on a stable base. The force exerted by the gauge shall be (0,59 + 0,l) N equivalent to - (60 zfi 10) g. 7.4.2 Selection of mass-disc combination An appropriate mass (30 g, 125 g, 500 g or 2 000 g) shall be selected so that the impression material layer under the first disc of 16 mm diameter has a thickness between 0,13 mm and 0,33 mm. When the thickness is found to exceed 0,33 mm with the 2 000 g mass, the 16 mm discs shall be replaced by those of 10 mm. If it is impossible to obtain a thickness within the prescribed range using any described combination, the actual layer thickness shall be accepted, for ex- ample, less than 0,33 mm with the 2 000 g mass and 10 mm discs. 7.4.3 Procedure Position six discs of the same diameter at regular intervals on the mould assembly and place this be- neath the dial gauge so that the spindle contacts the upper surface of the first disc. Read the dial gauge to the nearest 0,Ol mm and record the value as A,, & A,, A,, A, and A,. Remove the discs for use later in the same order and positions. Mix about 20 g of material according to the manu- facturer’s instructions. If a range of mixing times is given, use the shortest time recommended. Fill the mould assembly with mixed material and roughly level it with a spatula. Position the first disc on the surface of the mixed material and place the mould assembly on the base of the loading device. Apply the appropriate load to the first disc 15 s after the end of mixing and maintain the load for 10 s. Place the other discs on the material, while the first disc is loaded. Load the second disc, again for 10 s, 30 s after the end of mixing. Load the remaining four discs each for 10 s at intervals and make measure- ments before and after the time at which the layer is expected to become twice the thickness of the layer under the first disc. After this loading sequence, transfer the whole as- sembly to the dial gauge. When the impression ma- terial shows evidence of setting, take readings with the spindle of the dial gauge in contact with each disc in turn and record these values to the nearest 0,Ol mm as B,, B2, II,, B4, B5 and B6. Record the dif- ference between the respective B and A readings, as the thickness of the impression material beneath each disc. Plot the values, B-A, against time on graph paper and draw the best curve through or near the points. 3 SIST EN 24823:2000
IS0 4823:1992(E) From the graph, obtain the time at which the thick- ness of impression material becomes twice the thickness obtained 15 s after the end of mixing (i.e. the first disc). 7.4.4 Expression of results Calculate the mean of three such determinations, rounded to the nearest 15 s and record as the total working time. Discard any individual value deviating by more than + 25 % from the mean and repeat the determination. If, however, more than one combination of load and disc satisfies the test requirem
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