1、STD*BSI BS EN IS0 7491-ENGL 2000 Lb24bb9 0882575 813 BRITISH STANDARD Dental materials - Determination of colour stability The European Standard EN IS0 7491:2 has the status of a British Standard ICs 11.060.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGRT LAW BS EN IS0 7491:2000
2、 STD-BSI BS EN IS0 74SL-ENGL 2000 3624bb7 088257b 75T BS EN IS0 7491:2000 been prepared under the Environment Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 December 2000 direction of the Health and Amd.No. Date O BSI 12-2000 ISBN O 580 366
3、12 X National foreword Comments This British Standard is the official English language version of EN IS0 7491:2000. It is identical with IS0 7491:2. It supersedes BS 67W1987 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CH/51, Prosthodontic material
4、s, which has the responsibility to: - aid enquirem to understand the text, - present to the responsible internationallEuropean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; - monitor related intemational and European developments and prom
5、ulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references Attention is dram to the fact that CEN and CENELEC Standards normally include an annex which lists nodve references to international publications with their corr
6、esponding European publications. The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the Find” facility of the BSI
7、Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards axe responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary o
8、f pages This document comprises a front cover, an inside front cover, the EN IS0 title page, the EN IS0 foreword page, the IS0 title page, pages ii to iv, pages 1 to 4, the annex ZA page and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued
9、. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 7491 September 2000 ICs 01.006.10 Supersedes EN 27491 :1991 English version Dental materials - Determination of colour stability (IS0 749 1 : 2000) Produits dentaires - Dtermination de la stabilit de couleur (IS0 7491:2000) Zahnrztliche Werk
10、stoffe - Bestimmung der Farbbestndigkeit (IS0 7491 :2000) This European Standard was approved by CEN on 1 September 2000. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard withou
11、t any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretanat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made
12、 by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland,
13、Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMEE FOR STANDARDIZATION COMITE EUROPEEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Central Secretariat: rue de Stassart, 36 8-1050 Brussels O 2000 CEN All rights of exploitation
14、 in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN IS0 7491:2000 E STDmBSI BS EN IS0 7491-ENGL 2000 U lb24bb9 0882578 522 EN IS0 7491:2000 Foreword The text of the International Standard IS0 7491 :2000 has been prepared by Technical Committee ISOTTC 106 “Dentistty
15、“ in collaboration with Technical Committee CENTTC 55 “Dentistry“, the secretariat of which is held by DIN. This European Standard supersedes EN 27491 :1991. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the
16、latest by March 2001, and conflicting national standards shall be withdrawn at the latest by March 2001. According to the CENEENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic,
17、Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard IS0 7491 :2000 was approved by CEN as a European Standard without any modificati
18、on. NOTE: Normative references to International Standards are listed in annex ZA (normative). STD-BSI BS EN IS0 7491-ENGL 2000 .I 1624bb9 0882579 469 EN IS0 7491:ZOOO INTERNATIONAL STANDARD IS0 7491 Second edition 2000-09-01 Dental materials - Determination of colour stabil i ty Produits dentaires -
19、 Dtermination de la stabilit de couleur Reference number IS0 7491:2000(E) STDeBSI BS EN IS0 7491-ENGL 2000 m Lb24bb9 0882580 180 m EN IS0 7491:2000 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work o
20、f 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, governmental and non-governmenta
21、l, 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Pari 3. Draft In
22、ternational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this Internation
23、al Standard may be the subject of patent rights. IS0 shall not be held responsible for identifying any or all such patent rights. International Standard IS0 7491 was prepared by Technical Committee ISOTTC 106, Dentistry, Subcommittee SC 2, Prosthodontic materials. This second edition cancels and rep
24、laces the first edition (IS0 7491 :1985), which has been technically revised. iii STD-BSI BS EN IS0 7491-ENGL 2000 lb24669 0882581 017 W EN IS0 7491:2000 Introduction Colour stability is an important characteristic of dental materials and it is expected that the test methods in this International St
25、andard will be referred to in the International Standards specifying such materials. iv STD-BSI BS EN IS0 IYSL-ENGL 2000 m 162Ybb 0882582 T53 W EN IS0 7491:2000 Dental materials - Determination of colour stability 1 Scope This International Standard specifies a method for the determination of the co
26、lour stability of dental materials after exposure to light and water. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions
27、of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative d
28、ocument referred to applies. Members of IS0 and IEC maintain registers of currently valid International Standards. IS0 3696, Water for analytical laboratory use - Specification and test methods. IS0 4892-2, Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc sources. CIE P
29、ublication 15.2, Colorimetry. 3 Test methods 3.1 Apparatus 3.1.1 Radiation source Xenon medium-pressure lamp with a colour temperature of 5 O00 K to 10 O00 K and with an illuminance at the specimen of 150 O00 Ix. Any deviation of the illuminance from the mean value at any given moment shall not exce
30、ed f 10 YO over the entire area occupied by the test specimen, measured in accordance with IS0 4892-2. Other radiation sources of performance equivalent to the xenon lamp are also suitable. The xenon lamp and the ultraviolet filter (3.1.2) should normally be replaced after 1 500 h use because of the
31、 change in radiation intensity due to ageing. The illuminance should be measured with a suitable illumination meter and the illuminance adjusted accordingly. 3.1.2 90 % above 370 nm. Ultraviolet filter, of borosilicate glass, with transmittance of less than 1 % below 300 nm and greater than 3.1.3 Te
32、st chamber The test chamber comprises the following components. 1 - STD-BSI BS EN IS0 ?LiSL-ENGL ZOO0 m Lb24bb9 0882583 99T 111 EN IS0 7491:2000 3.1.3.1 Circulating water bath The water, complying with grade 2 of IS0 3696, shall be maintained at (37 f 5) “C and at a depth of (10 f 5) mm above the sp
33、ecimens, which are held parallel to the bottom of the chamber. 3.1.3.2 Specimen holder, of an opaque material, preferably metal, for specimen discs up to 50 mm diameter. A suitable holder is shown in Figure 1 Dimensions in millimetres # - = 60 Key 1 Clamping plate 2 Base plate 3 Screw 4 NOTE Spacer,
34、 of dimension d adjusted to the thickness of the specimen The holder may be designed for one or several specimens. Figure 1 - Holder for specimen discs up to 50 mm diameter 3.2 Procedure 3.2.1 Specimen preparation Individual dental material standards specify specimen size, method of preparation and
35、conditioning as well as the method of preparing a reference specimen. Such standards shall be used in conjunction with this International Standard. 3.2.2 Radiation test Either clamp one-half of the specimen in the holder, as shown in Figure 1, or cover one-half of the specimen with tin or aluminium
36、foil. For specimen teeth, cover half of the vestibular surface with tin or aluminium foil parallel to the long axis of the tooth. With the ultraviolet filter (3.1.2) in position, place the test specimens in the water bath and expose them to the radiation of the xenon lamp (3.1 .l) for (24 f 1) h. Ta
37、ke care to avoid casting shadows on the specimens. 2 STD.BSI BS EN IS0 7491-ENGL 2000 = 1b24bb 0882584 82b = EN IS0 7491:ZOOO 3.2.3 Colour comparison Use three people with normal colour vision to compare by visual inspection the exposed and unexposed halves of each of the specimens and the unirradia
38、ted specimen for any colour differences. The normal colour vision of the observers shall be verified by a medical practitioner or other appropriately trained person. Corrective untinted lenses may be worn. Make the comparison in bright diffuse daylight under an overcast “northern/southern“ sky or, a
39、lternatively, under a xenon or equivalent lamp corresponding to D65, in accordance with CIE Publication 15.2, without any significant coloured reflection and using an illuminance of 1 O00 Ix to 2 O00 Ix. For disc-shaped specimens, place a diffuse white background of reflectance about 90 % (white bon
40、dpaper is suitable) behind the samples. Limit the background to the size of the disc and surround it by a diffuse grey background with a reflectance of (30 f 5) YO. For tooth-shaped specimens, use a diffuse grey background with a reflectance of (30 f 5) YO. Allow the three observers to view the spec
41、imens at a distance of 200 mm to 300 mm for a period of not longer than 2 s. Record the independent comparisons of the three observers. In the event of disagreement between the observers, the majority view shall be reported. 3 STDeBSI BS EN IS0 7491-ENGL 2000 M lb24bb9 0882585 7b2 H EN IS0 7491:2000
42、 Bibliography l IS0 4582:1998, Plastics - Determination of changes in colour and variations in properties after exposure to daylight under g/ass, natural weathering or laboratory light sources. IS0 4892-1 :1994, Plastics - Methods of exposure to laboratory light sources - Part 1: General guidance. 2
43、 4 STD-BSI BS EN IS0 7492-ENG1 2000 .CI Lb24669 088258b bT m EN IS0 7491:ZOOO Annex ZA (normative) Normative references to international publications with their relevant European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These
44、 normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated
45、 references the latest edition of the publication referred to applies. Publication - Year Title - EN yeaJ IS0 3696 1987 Water for analytical laboratoty use - EN IS0 3696 1995 Specification and test methods IS0 4892-2 1994 Plastics - Methods of exposure to EN IS0 4892-2 1999 laboratory light sources
46、- Part 2: Xenon-arc sources STDmBSI BS EN IS0 7491-ENGL 2000 E Lb2rlbb9 0882587 535 II BS EN IS0 7491:ZOOO BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standar
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