1、BRITISH STANDARD CONFIRMED FEBRUARY 1993 BS 6747:1987 Incorporating Amendment No. 1 Specification for Orthodontic resins UDC 616.314-089.23:678.744.3BS6747:1987 This British Standard, having been prepared under the directionof the Health Care Standards Committee, was published under the authority of
2、the Board of BSI and comes intoeffect on 30January1987 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference HCC/51 Draft for comment 81/52747 DC ISBN 0 580 15480 7 Committees responsible for this British Standard The preparation of this British Standard w
3、as entrusted by the Health Care Standards Committee (HCC/-) to Technical Committee HCC/51, upon which the following bodies were represented: Association of Dental Hospitals of the United Kingdom British Ceramic Research Association British Dental Association British Dental Trade Association British
4、Institute of Surgical Technologists British Society for the Study of Orthodontics British Society for the Study of Prosthetic Dentistry Dental Laboratories Association Limited Dental Materials Panel Department of Conservative Dentistry Department of Health and Social Security General Dental Practiti
5、oners Association Ministry of Defence Orthodontic Technicians Association Society of University Dental Instructors Amendments issued since publication Amd. No. Date of issue Comments 6663 April 1991 Indicated by a sideline in the marginBS6747:1987 BSI 10-1999 i Contents Page Committees responsible I
6、nside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Materials 1 4 Manufacturers instructions 2 5 Sampling 2 6 Preparation and conditioning of test specimens 2 7 Packaging 2 8 Marking of packages and containers 2 Appendix A Method for determining thermal stability of liquids 3 Appendix B Method
7、 for determining transverse deflection 3 Appendix C Method for determining residual methyl methacrylate monomer 4 Appendix D Method for determining water sorption 5 Appendix E Guidance on the determination of the diffusion coefficient 5 Appendix F Method for determining impact strength 6 Appendix G
8、Method for determining hardness and creep 7 Appendix H Bibliography 7 Figure 1 Water uptake 6 Figure 2 Pattern of the test specimen plate for transverse deflection test 8 Figure 3 Pattern of the test specimen plate for residual methyl methacrylate monomer 8 Figure 4 Pattern of test specimen plate fo
9、r water sorption 9 Figure 5 Pattern of test specimen plate for impact strength 9 Publications referred to Inside back coverBS6747:1987 ii BSI 10-1999 Foreword This British Standard was prepared under the direction of the Health Care Standards Committee. Resins based on polymethyl methacrylate (PMMA)
10、 have been used in the construction of both active and passive removable orthodontic appliances for many years. Initially, denture base resins were used for orthodontic appliances, although modified resins, more suited to orthodontic applications, have become available as a result of the continuing
11、development of denture base resins. In addition, techniques of processing have been adopted that are better suited to the orthodontic technician, one of the most important of which is a method of polymerizing the monomer directly on a cast, frequently described as the pepper and salt technique. This
12、 involves wetting the cast and spraying on polymer powder, wetting with monomer and then adding more polymer. An incremental system of polymer build-up has therefore evolved which, with technical skill, may be accomplished rapidly and satisfactorily. This method of preparing the resin part of the re
13、movable orthodontic appliance has several potential problems. The resin may be weaker than if conventional flasking and heat systems of polymerization were used, and there may be a greater risk that an appliance will have more residual than for denture base resin monomer. In addition, the high monom
14、er content of the polymer/monomer mix causes increased contraction of the resin on polymerization. This standard is more comprehensive with regard to performance requirements than BS 2487. In particular, this standard includes requirements and test methods for impact strength and residual monomer wh
15、ich are not included in BS2487and it is intended that these additional requirements will be included in the next revision of BS 2487. This British Standard has been prepared primarily on the basis of data produced by a research programme undertaken under the direction of Dr G D Stafford at Cardiff D
16、ental School. This research took into account replies to a questionnaire sent to the members of the Orthodontic Technicians Association and to Dental Schools, whose assistance in furnishing information on materials and techniques has been invaluable. Requirements for freedom from biological hazards
17、are not included in this British Standard but it is recommended that in assessing possible biological or toxicological hazards, reference be made to BS 5828. Attention is also drawn to HSE Guidance Note EH40and to the Health and Safety at Work etc. Act, 1974. A British Standard does not purport to i
18、nclude all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pa
19、ges i and ii, pages1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6747:1987 BSI 10-1999 1 1 Scope This British Standard specifies p
20、erformance requirements and describes methods of test for the resins made of acrylic monomers and polymers and used in the construction of removable orthodontic appliances. Such resins, prepared from a powder (polymer) and a liquid (monomer), are polymerized in an open mould by means of a chemically
21、-activated system accompanied by a combination of heat and pressure. This standard does not specify requirements for dough-moulded orthodontic resins, which are specified in BS 2487. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions Fo
22、r the purposes of this British Standard the definitions given in BS 4492 apply, together with the following. 2.1 test specimen plates raw, unfinished plates as cast or moulded, without any finishing 2.2 test specimens test specimen plates after finishing, i.e. in a suitable form for testing 2.3 test
23、 specimen strips test specimens which have been sawn into strips 3 Materials NOTEFor assessment of freedom from biological hazards of dental materials reference should be made to BS 5828. 3.1 Liquid 3.1.1 General. The liquid shall consist of polymerizable acrylic material and other ingredients appro
24、priate to the polymerization system. It shall be free from deposits or sediment when examined visually. 3.1.2 Thermal stability. The liquid shall show no turbidity, deposits or sediment when tested in accordance with Appendix A. 3.2 Powder The powder shall consist of acrylic polymers and other ingre
25、dients appropriate to the polymerization system. It shall be free from extraneous material when examined visually. 3.3 Polymerized resin 3.3.1 Surface properties. When processed in accordance with the manufacturers instructions and prepared in accordance with B.1.1 to B.1.4, test specimens shall hav
26、e a surface which, when polished by a conventional dental method, shall be capable of producing a high gloss. 3.3.2 Colour. The colour of the processed resin, when assessed visually using the test specimen prepared in accordance with B.1.1 to B.1.4, shall be as stated by the manufacturer see 8.1 c).
27、 3.3.3 Residual methyl methacrylate monomer. The resin, when tested in accordance with Appendix C, shall contain not more than3.5% by mass of methyl methacrylate monomer. 3.3.4 Freedom from porosity. When processed in accordance with the manufacturers instructions and prepared in accordance with B.1
28、.1 to B.1.4, test specimens shall not show evidence of surface or internal porosity when viewed without magnification. 3.3.5 Water sorption. When tested in accordance with Appendix D, the increase in mass of the test specimen shall not exceed3%. NOTEThe maximum water sorption is achieved after appro
29、ximately4weeks; however,85% to90% of the maximum uptake is achieved after1week and this test therefore reflects a balance between practical and theoretical considerations. The rate of water uptake or loss may be an important parameter and guidance on the determination of the diffusion coefficient ha
30、s therefore been given in Appendix E for information. 3.3.6 Transverse deflection. The transverse deflection, when tested in accordance with Appendix B, shall be not greater than5.0mm over the force range15N to30N. 3.3.7 Impact strength. The impact strength, when tested in accordance with Appendix F
31、, shall be not less than800J/m 2 . 3.3.8 Hardness. The mean indentation value, when tested in accordance with Appendix G, shall not exceed160units (40 4m). 3.3.9 Creep. The creep value, when measured in accordance with Appendix G, shall not exceed20% of the original depth of penetration at5s.BS6747:
32、1987 2 BSI 10-1999 4 Manufacturers instructions Instructions for storing, preparing and processing the resin shall accompany each package, and shall include details of the following. a) The recommended powder/liquid ratio(s). NOTEThis is applicable only to materials that are mixed together prior to
33、use. b) The procedure for mixing or preparing the resin for use. c) The manipulation time. d) Instructions for the preparation of the cast. e) The recommended applied pressure and the time temperature cycle for polymerization. f) Instructions for repair of the resin. g) Hazard warning, where applica
34、ble, for toxic, hazardous, flammable, or irritating characteristics. 5 Sampling A representative sample of sufficient powder and liquid to complete all the tests shall be obtained from one batch. 6 Preparation and conditioning of test specimens Test specimens shall be prepared in accordance with the
35、 manufacturers instructions, at a temperature of23 2 C and a relative humidity of50 10%. 7 Packaging The material shall be supplied in sealed containers made of materials which shall neither contaminate nor permit contamination of the contents. The containers shall be packaged so as to prevent damag
36、e or leakage during transit and storage. Liquid components shall be supplied in opaque containers. 8 Marking of packages and containers 8.1 Packages Each outer package shall be clearly marked with the following information: a) the manufacturers registered name or mark; b) the contents of the package
37、 and the batch number; c) the colour; d) the recommended conditions of storage; e) the flash-point of liquid in the package in C; f) the expiry date of any component that has a limited shelf-life; g) a hazard warning, where appropriate, for toxic, hazardous, flammable, or irritating characteristics;
38、 h) the number and date of this British Standard, i.e. BS 6747:1987 1) . 8.2 Individual containers Each container shall be clearly marked with the following information: a) the manufacturers registered name or mark; b) the batch number; c) the mass of solids (in grams) and volume of liquid (in milli
39、litres); d) any special precaution needed in handling the material, particularly with regard to flammability; e) the date of manufacture of the liquid (i.e. date at which it was formulated) (month and year); f) the colour; g) the expiry date of any component that has a limited shelf-life. 1) Marking
40、 BS 6747:1987 on or in relation to a product is a claim by the manufacturer that the product has been manufactured to the requirements of the standard. The accuracy of such a claim is therefore solely the manufacturers responsibility. Enquiries as to the availability of third party certification sho
41、uld be addressed to the appropriate certification body.BS6747:1987 BSI 10-1999 3 Appendix A Method for determining the thermal stability of liquids Place10mL of the liquid in a test tube, cover to prevent evaporation and leave for24h at60 2 C in the absence of light. After24h, cool to23 2 C and pour
42、 a1mL portion into a test tube containing20mL of analytical grade methanol. After5min, examine the liquid for turbidity, deposits or sediment. Appendix B Method for determining transverse deflection B.1 Preparation of test specimens B.1.1 Apparatus and materials B.1.1.1 Pattern of the test specimen
43、plate, in metal or resin, of dimensions as shown in Figure 2. B.1.1.2 Equipment for processing the resin B.1.1.3 Dental artificial stone complying with BS4796. B.1.1.4 A range of silicon carbide papers, including600 grade 2) . B.1.1.5 Separating medium B.1.2 Preparation of the mould Invest the patte
44、rn of the test specimen plate(B.1.1.1) in dental artificial stone (B.1.1.3) and remove1h after the dental artificial stone has set. Cover the test specimen plate area of the mould with the separating medium (B.1.1.5). B.1.3 Preparation of test specimen plates Using the mould, prepare two test specim
45、en plates separately in accordance with the manufacturers instructions. B.1.4 Preparation of test specimens On removal from the mould, polish the test specimen plates using conventional dental methods and examine them for compliance with 3.3.1, 3.3.2 and 3.3.4. B.1.5 Preparation of test specimen str
46、ips Prepare six test specimen strips (from the two test specimens) at least64mm long,10.00 0.03mm wide, and2.50 0.03mm thick by sawing each test specimen plate lengthwise into three equal test specimen strips. Machine the test specimen strips equally on the edges and both moulded surfaces so that th
47、e dimensions are slightly oversize. Use water or cold air, or a sufficiently slow machining speed in order to avoid overheating the test specimen strips. Wet grind the surfaces using progressively finer grades of silicon carbide paper, using600grade for the final finishing stage and water as a lubri
48、cant. NOTEA mechanical surfacing device may alternatively be used to finish the specimens. For information on the availability of suitable devices apply to Enquiry Section, BSI, Linford Wood, Milton Keynes MK 14 6LE. B.1.6 Conditioning Store the test specimen strips in distilled water at37 2 C for7d
49、ays. B.2 Apparatus B.2.1 Testing machine, calibrated, having a constant cross-head speed of51mm/min and equipped with a device for measuring the deflection of the centre of the specimen to within0.025mm. Any load exerted by the deflection-measuring device shall be accounted for when calibrating the machine. B.2.2 Transverse testing rig, consisting of a central loading plunger and two supports having highly polished cylindrical surfaces of diameter3.2mm and length10.5mm. The supports shall be parallel to within0.1mm and perpendicular to the l
