BS 5189-3-1975 Dental casting investments - Ethyl silicate-bonded investment materials《牙科铸造包埋料 第3部分 硅酸乙酯粘结的牙科铸造包埋料》.pdf
《BS 5189-3-1975 Dental casting investments - Ethyl silicate-bonded investment materials《牙科铸造包埋料 第3部分 硅酸乙酯粘结的牙科铸造包埋料》.pdf》由会员分享,可在线阅读,更多相关《BS 5189-3-1975 Dental casting investments - Ethyl silicate-bonded investment materials《牙科铸造包埋料 第3部分 硅酸乙酯粘结的牙科铸造包埋料》.pdf(14页珍藏版)》请在麦多课文档分享上搜索。
1、BRITISH STANDARD BS 5189-3: 1975 Specification for Dental casting investments Part 3: Ethyl silicate-bonded investment materials UDC 616.314089.27:661.718.5BS5189-3:1975 This British Standard, having been approved by the Dental Industry Standards Committee,was published underthe authorityof the Exec
2、utive Boardon 27March1975 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference DNMH/4/3 Draft for comment 73/60911 ISBN 0 580 08901 0 Co-operating organizations The Dental Industry Standards Committee, under whose supervision this British Standard was pre
3、pared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Dental Hospitals of Great Britain and Northern Ireland* British Dental Association* British Dental Trade Association* British Plastics Federation Dental Education
4、Advisory Council Department of Health and Social Security* Department of Industry Laboratory of the Government Chemist* Department of Industry National Engineering Laboratory Ministry of Defence* Royal Society of Medicine Scottish Home and Health Department The Government departments and scientific
5、and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Institute of Surgical Technicians Dental Laboratories Association Institute of Dental Surge
6、ry London Dental Study Club Individual expert Amendments issued since publication Amd. No. Date of issue CommentsBS5189-3:1975 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Reference 1 3 Requirements 1 4 Sampling 1 5 Test methods 1 6 Marking 4 Appe
7、ndix A Conversion table 5 Figure 1 Diagram of thermal expansion equipment 6 Figure 2 Mould and former used in thermal expansion test 7 Figure 3 Transverse strength test apparatus 7 Figure 4 Diagram of furnace and lever system suitable for high temperaturetransverse strength tests 8 Publication refer
8、red to Inside back coverBS5189-3:1975 ii BSI 12-1999 Foreword This British Standard forms one of a series on dental equipment and materials, prepared under the authority of the Dental Industry Standards Committee. The technique employed in mixing and using dental casting investments is almost as cri
9、tical as their chemical composition in governing their behaviour and properties under normal laboratory conditions. This fact is known, appreciated and made use of both by those people handling dental investments and by those responsible for their manufacture. It does, however, make the specificatio
10、n of a standardized mixing technique and consistency for use in preparation of the test specimen quite impossible, and reference has therefore been made to the manufacturers instructions. To safeguard the interests of the consumer in this respect, special attention has been paid to the subject of in
11、formation on mixing techniques and expansion, with a requirement that ample data on these items be included in every package of material. Ethyl silicate investment materials have a number of characteristics which set them apart from other dental casting materials. Firstly, there is the critical impo
12、rtance of the particle size distribution in the setting reaction and thermal expansion unless the manufacturer uses a suitable mixture of particle sizes the material will not set and the expansion will be unsatisfactory. As such a deficiency will automatically preclude an investment from even being
13、considered for compliance with the terms of a specification, the committee responsible for this standard decided that the inclusion of the usual sieving test, which features in Parts1 and2, was unnecessary. Another characteristic is the prolonged gelling type of reaction which takes place during set
14、ting. This presents a number of problems in definition and determination of what could be described as a set condition, and in this instance also it was considered that with the safeguard provided by the other requirements for physical properties, there was no immediate need for inclusion of a speci
15、al test just to determine an arbitrary set for these materials. Lastly, it will be noticed that the requirement for high temperature transverse strength in this specification is slightly lower than that set for gypsum and phosphate investment materials. This is because, due to practical difficulties
16、 in actual testing, the strength of ethyl silicate materials is determined at a temperature significantly below that used in actual casting when the maximum strength will be obtained. In preparing this British Standard the opportunity has been taken to use, where applicable, SI metric units. Recogni
17、zing that some of these units may be unfamiliar, a conversion table is included inAppendix A 1)which should provide a sufficient range of equivalent values for the interpretation of the relevant clauses. Certification. Attention is drawn to the certification facilities described on the inside back c
18、over of this standard. A British Standard does not purport to include 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 T
19、his document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, 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. 1) Info
20、rmation on the international (SI) system of Units is given in BS3763 “The International System of units (SI)” and PD5686 “The use of SI units”. Tables of conversions are given in BS350“Conversion factors and tables”, Part1 “Basis of tables. Conversion factors”.BS5189-3:1975 BSI 12-1999 1 1 Scope Thi
21、s British Standard specifies requirements for ethyl silicate-bonded investment materials supplied as two or more components for use in dental casting procedures. 2 Reference The title of the British Standard referred to in this standard is given on the inside back cover. 3 Requirements 3.1 Component
22、s. The manufacturer or supplier of the investment powder shall also supply the ethyl silicate component and give full information on all other components required (see3.5). 3.2 Powder. The investment powder shall be free from undesirable extraneous material and lumps. Colouring matter shall not be r
23、egarded as extraneous material. 3.3 Expansion. The mixed investment, when tested not less than24h after the first contact of investment and binder liquid as described in5.2, shall exhibit a total expansion (covering air setting and thermal behaviour) of not less than1.5%. (Seealso further reference
24、to expansion in3.5.) 3.4 Transverse strength 3.4.1 Low temperature (green strength). The transverse strength of the set investment test pieces24h after the commencement of mixing, determined at a temperature of23 2 C and in the manner described in5.3, shall be not less than0.4MN/m 2 . 3.4.2 High tem
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