Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 7966 (1976): Dental Modelling Wax [MHD 8: Dentistry]

IS : 7966 - 1976

lndian StandardSPECIFICATION FOR

DENTAL MODELLING WAX

Dental Materials Sectional Committee, CDC 52

Chairman

D R N. K. AQRAWAL

Dental College & Hospital, Lucknow

Mem hers

DR P. K. BASUDRK.S.GILL

Refircsenting

Dr R. Ahmed Dental College & Hospital, CalcuttaPunjab Government Dental College & Hospital,

AmritsarDR(SMT)T.M.S.GINWALLA

DR F. D. MIRZA (Alternate )SHRIA.K.GOVANDE

SHRI DESMONDDE BEYNACSHEEN ( Alternate )

DR B. GOVERDRAN HEQDED R ISHAR S~NCJHD R R. C. KAKAR

Nair Hospital & Dental College, Bombay

Dental Products of India Ltd, Bombay

Government Dental College, BangaloreGovernment Medical College, PatialaIn personal capacity ( 31 South Pafrl .Nagar, .New

Delhi )M A J- GEN M. D. ME H R A

COL 0. P. BHATIA ( Alternate ),. - - -

Ministry of Defence ( DGAFMS )

3mu BEUPENDRA B. YATEL Dental Corporation of India, BombaySHRI NARENDRA M. PATEL (Alternate )

SHRI D. G. PATWARDH~N Directorate General of Technical Development,New Delhi

S HRI M. M. RAWAL Indo-Ceylon Dental & Surgical Co Ltd, MadrasSHRI B. M. RAWAL ( Alternate )SEIRI V. M. RAWAL (Alternate )

DR N. PINTO Do ROZARIO Ministry of Health & Family Planning, New Delhi;and Willingdon Hospital, New Delhi

DR G. B. SHANKWALKAR Government Dental College & Hospital, Bombay;and Government Dental College & Hospital,Nagpur

DR BALRAJ SURD R G. M. SAXEYA

Director ( Chem ‘)

Indian Eental Association, New DelhiDirector General, IS1 ( Ex-o#cio Member )

SERI NARESH K. SHARMADeputy Director ( Chem ), IS1

( Continued on page 2 )

@ Copyright 1976

INDIAN STANDARDS INSTITUTIONThis publication is protected under the Indian Copyright Act (XIV of 1957 ) andreproduction in whole or in part by any means except with written permission of thepublisher shall be deemed to be an infricgement of copyright under the said Act. I

IS : 7966 - 1976

( Continued from page 1 )

Denture Materials Subcommittee, CDC 52 : 2

Convener Representing420~0. P. BHATIA Ministry of Defence ( DGAFMS )

MembersDa N. K. AQRAWAL In personal capacity ( Dental College & Hospital,

Lucknow )SHRI A. K. G O V A N D E Dental Products of India Ltd, Bombay

SHRI S. R. SETHNA ( Alternate )DB B. GOVERDHAN HE~DE Government Dental College, BangaloreD R JACOB HYSON Governmeot of Kerala, Health ( B) Department,

TrivandrumDR INDERJIT SINQH.DR C. N. KOTHARE

Safdarjang Hospital? New DelhiUnichem Laboratorres Ltd, Bombay

Srrar P. G. VYAS ( Alternate ).PROF S. B. MASTER Government Dental College & Hospital, BombayM A J- GEN M. D. MEERA Ministry of Defence ( DGAFMS )P ROF B. SIHRAM MURTHY Osmania Medical College, HyderabadSHRI M. M. RAWAL Indo-Ceylon Dental & Surgical Co Ltd, Madras

SHRI B. M. RAWAL ( Alternate )SHBI V. M. RAWAL ( Alternate )

2

!IS:7966-1976

Indian StandardSPECIFICATION FOR

DENTAL MODELLING WAX

0 . F O R E W O R D

0.1 This Indian Standard was adopted by the Indian Standards Institutionon 20 January 1976, after the draft finalized by the Dental MaterialsSectional Committee had been approved by the Chemical DivisionCouncil.

0.2 The modelling wax is used in the construction of artificial dentures.

0.3 In the preparation of this standard, considerable assistance has beenderived from AS T17-1961 ‘Specification for dental modelling wax ’published by the Standards Association of Australia.

0.4 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall be rounded off in accord-ance with IS : 2-1960*. The number of significant places retained in therounded off value should be the same as that of the specified value in thisstandard.

1 . S C O P E

1.1 This standard prescribes the requirements and the methods ofsampling and test for dental modelling wax.

2, TYPES

2.1 The modelling wax shall be of the following two types:

Type A - For temperate weatherType B-For hot weather

3. REQUIREMENTS

3.1 Description-The wax shall be uniform and free from foreignmaterials and shall be supplied in the form of smooth sheets uniform intexture. Softened wax sheets shall cohere readily. The wax shall havepleasant odour and flavour and shall not irritate the oral tissues.

*Rules for rounding off numerical values ( revised ).

3

IS i 7966 d 1976

3.2 Size-Unless specified otherwise, the sheets of wax shall be notless than 75 mm wide and approximately 150 mm long, and shall be1’25 -k 0’15 mm thick.

3.3 Colour-The colour of the wax shall be preferably pink.

3.4 Clinical Requiiements

3.4.1 The wax shall soften without becoming flaky or crumbly andwithout adhering to the fingers.

3.4.2 When cooled to temperatures between 20°C and 25% for Type Awax, or between 25°C and 30°C for Type B wax, the wax shall retain-porcelain and synthetic resin teeth in place and shall trim easily with asharp instrument without appreciable tearing, chipping or flaking.

3.4.3 No appreciable residue shall remain on porcelain or syntheticresin teeth and colouring matter shall not separate from the wax or im--pregnate the plaster when the wax is flushed from the flask with boilingwater.

3.4.4 The wax shall have a smooth glossy surface after gentle flaming.

3.5 Flow -The plastic deformation ( flow ) of the wax, when determinedas prescribed in A-l, shall comply with the requirements given inTable 1.

TABLE 1 PLASTIC DEFORMATION ( FLOW )

T EMPERATURE FLOW,PERCENTr_-______h-------7

Type A Type Br---1 r_----h----7Min Ma.% Min Max

(1) (2) (3) (4) (5)

“C37.0 - 2 - -

40.0 - 25 - 243.0 55 - - 2546.0 - - 55 -

3.6 Linear Shrinkage-The linear shrinkage of the wax, when deter-mined as prescribed in A-2, shall not exceed 0.8 percent.

3.7 Ductility-The ductility of the wax shall be such that when testedas prescribed in A-3, the sheet shall not show brittle fracture when bentdouble at a temperature of 20 f 1°C for Type A and a temperature of25 f 1°C for Type B.

4

ISr7966-1976

3.8 Adhesion on Storage -The adhesion on storage of the wax shallbe such that when tested as prescribed in A-4 there shall be no evidenceof damage to the wax surface J that were in contact with each other orwith the paper, where separating paper is used, and the wax and papersurfaces shall separate clearly and readily.

4. PACKING AND MARKING4.1 Packing-The wax shall be packed in suitable containers as agreedto between the purchaser and the supplier.4.2 Marking-Each container shall be securely closed and shall belegibly and indelibly marked with the following information:

a) Name and type of the material;b) Name of the manufacturer and his recognized trade-mark, if

any;c) Net mass;d) Batch number; ande) Date of manufacture.

4.2.1 The containers may also be marked with the ISI CertificationMark.

NOTE -The use of the IS1 Certification Mark is governed by the provisions of theIndian Standards Institution (Certification Marks) Act and the Rules and Regu-lations made thereunder. The IS1 Mark on products covered by an Indian Standardconveys the assurance that they have been produced to comply with the requirementsof that standard under a well-defined system of inspection, testing and qualitycontrol which is devised and supervised by IS1 and operated by the producer. IS1marked products are also continuously checked by IS1 for conformity to that standardas a further safeguard. Details of conditions under which a licence for the use ofthe ISI Certification Mark may be granted to manufacturers or processors, may beobtained from the Indian Standards Institution.

5. SAMPLING5.1 Representative samples of the material shall be drawn as prescribedin Appendix B or as agreed to between the purchaser and the supplier.

A P P E N D I X A( Clauses 3.5 to 3.8)

METHODS OF TEST FOR DENTAL MODELLING WAX

A-l. DETERMINATION OF FLOW

A-l.1 ApparatusA-1.1.1 Micrometer CaliperA~1.1.2 Flow Testing Instrument -The flow testing instrument (see

Fig. 1 ) consists of a metallic cylinder A, a non-conducting shaft B and abrass plate C. The total mass in air of the three components is 2000 g.

IS : 7966 - 1976

The cylinder A shall be separated from the plate C on the shaft B by aminimum distance of 75 mm. The shaft shall be of hard rubber or of simi-lar poor thermal conductor to avoid loss of heat due to conduction. Thediameter of the brass plate which touches the test specimen shall be notless than 50 mm. The thickness of the plate shall not exceed 6.5 mm.

FIG. 1 FLOW TESTING INSTRUMENT

A-1.1.3 Mould- Shown in Fig. 2, consisting of a stainless steel plate6’0 mm thick,. having flat parallel top and bottom surfaces, and contain-ing four holes, each 10.0 mm in diameter. The axes of the holes shall.be perpendicular to the surfaces of the plate. The sides of the holesshall be finished smooth.

6

IS : 7966 - 1976

6mm

F I G. 2 M OULD FOR F ORMING F L O W T E S T S P E C I M E N S

A-l.2 Preparation of Test Specimens- Break a quantity of waxinto pieces and place in an iron crucible of 50 ml capacity. Place thecrucible on a surface which is 130 mm below a 250-W infra-red lamp.Allow the wax, while being stirred, to melt and maintain at this tem-perature until the sample is melted throughout. Use a thermometer tomeasure the temperature. Then pour the melted wax into the mouldthat has been lubricated with a silicone grease whose melting point ishigher than 80°C. Preheat the mould to 55 f 5°C and place on a smoothglass sIab ( 150 mm long, 75 mm wide and 20 mm thick) also preheatedto the same temperature. As the wax solidifies and a shrinkage voidappears, add more of the melted wax. When the wax has lost its mirror-like surface, piace on top of the mould a smooth flat tin-foil or aluminium-foil covered glass plate preheated to 55 f 5°C. Apply a load of 90 N(9 kgf) to the top of the foil-covered glass plate for 30 minutes. Thenremove the load and the glass plate and trim away the excess wax bydrawing a straight-edged metal scraper across the mould thereby trim-ming the specimen flush with the surface. Remove the mould from theglass plate by gently tapping the side of the mould. Remove the speci-mens of wax from the mould by chilling in water at 10°C and then storeat 27 f 2°C for 24 hours before testing.

A-l.3 Procedure-Measure the initial length of the specimen at 27 f 2°Cusing a micrometer caliper. Make four measurements around the cir-cumference and one measurement on the centre of the specimen. Recordthe average of the measurements to the nearest 0.005 mm. Place thespecimen and the flow testing instrument in a water-bath and keep at thetesting temperature for 20 minutes prior to testing. Control the tempe-rature of the bath to within 0’1°C of the required temperature (use acalibrated thermometer for determining the temperature ) . Provide foragitation in the water-bath by means of a mechanical stirrer. Place athin sheet of waterproof cellulose film between the instrument and eachend of the specimen. The bottom of the specimen shall be 50 mm below

7

IS : 7966 - 1976

the surface of the water in the bath. Apply a constant axial load of19.6 N (2 kgf) to the specimen for 10 minutes, after which remove thespecimen and cool in air to 27 f 2°C. Strip off the cellulose film anddetermine the final length in the same manner as the original length.

A-l.4 Expression of Results -Calculate flow, as evidenced by thechange in length, as a percentage of the initial length. The value forflow at any temperature shall be the mean value for two specimens andshall be reported to the nearest 0.1 percent.

A-2. DETERMINATION OF LINEAR SHRINKAGE

A-2.1 Apparatus

A-2.1.1 Micrometer Microscofie Comparator,- or an equivalent instrumentof equal accuracy.

A-2 .1 .2 Brass Mould-305 mm in length , having an opening of6’35 x 6.35 mm running into full length, with spacers 19 mm in lengthat each end (see Fig. 3 ).

yl3aTOP PLATE

L 6.35 WAX SPECIMEN

MOULD

All dimensions in millimetres.

F I G. 3 BRASS M O U L D

IS : 7966 - 1976

A-2.1.3 Holder-As shown in Fig. 4. It has openings at the top forviewing the reference marks for linear measurements. These openingsshall be located at 6.3 mm from each end of the holder and shall be10 X 13 mm in size. The holder is so constructed that the wax specimenrides against only two narrowed sections, having 8 x 8 mm openings,located 25 mm from each end, to enable alignment with a minimum ofrestraint to expension during heating.

13x95 OPENING\

All dimensions in millimetres.

F I G. 4 H O L D E R

A-2.2 Preparation of Test Specimens-Melt the wax as prescribedin A-l.2 and pour into the brass mould, lubricated with a silicone greasewhose melting point is higher than 8O”C, until the mould is overfilled.Preheat the mould to 55 =t 5°C. As the wax solidifies and shrinkageoccurs, add the melted wax. When the wax has lost its mirror-like sur-face, place on top of the overfilled mould a lubricated brass plate, pre-heated to 55 f 5°C. Apply a load of 90 N (9 kgf) to ,the top of thebrass plate for, 30 minutes. Remove the weight and the brass plate andtrim away the excess wax until the specimen is flush with the top of themould. The size of the specimen thus prepared will be approximately267 x 6’35 x 6.35 mm and is suitable for use with a micrometer microscopecomparator. Remove the specimen from the mould and embed in itssurfaces near each end, small metal pins having cross marks which serveas reference marks for subsequent linear measurements. After preparingthe test specimens store them at 37°C for 24 hours before testing.

A-2.3 Procedure-Not less than 24 hours and not more than one week ,after the preparation of the specimen, place the specimen in a water-bathmaintained at 40’0 f l*O”C. At the end of 20 minutes, measure thelength of the specimen and transfer the specimen forthwith to a water-bath maintained at 20’0 f 0’5°C. At the end of 40 minutes, measure thelength of the specimen again.

A-2.3.1 Express the change in length as a percentage of the length ofthe specimen at 40°C. Obtain the average of the values on two suchspecimens and record as the linear shrinkage and report to the nearest0.05 percent.

ISt7966-1976

A-3. TEST FOR DUCTILITY

A-3.1 Procedure - Maintain a sheet of wax at the temperature speci-fied and then bend it across its breadth in 10 seconds at a uniform rateuntil it is doubled with the two halves of the specimen in contact alongtheir entire length. Repeat the test by bending the sheet of wax alongits length.

A-3.1.1 Observe whether the wax shows brittle fracture.

A-4. TEST FOR ADHESION ON STORAGE

A-4.1 Apparatus

A-4.1.1 Flat Rigid Platens - 50 x 63 mm and at least 5 mm thick.

A-4.1.2 Load - 1 kg including the mass of the top platen.

A-4.1.3 Electric Oven -which can be maintained at a temperature of4oi 1°C.

A-4.2 Procedure -Prepare three specimens of wax and a specimen ofseparating paper, where such is used, of dimensions 50 X 75 mm. Thenplace the specimens between the platens in such a manner that 12 mm ofeach specimen projects from one end of the platens and the separatingpaper, where used, is between two of the wax specimens. Place theassembled specimens in an oven maintained at a temperature of 40 f 1°Con a flat rigid surface and apply a mass of 1 kg including the mass of topplaten. At the end of 24 hours remove the specimens and allow to coolto room temperature. At the end of 2 hours separate the specimens byopening from the overlapping ends, and examine the surfaces in contactwith other specimens for evidence of damage.

A P P E N D I X B( Clause 5.1 )

SAMPLING OF DENTAL MODELLING WAX

B-I. GENERAL REQUIREMENTS OF SAMPLING

B-I.0 In drawing, preparing, storing and handling test samples, the pre-cautions and directions given in B-l.1 to B-I.5 shall be observed.

B-I.1 Samples shall not be taken in an exposed place.

B-I.2 Precautions shall be taken to protect the samples, the materialbeing sampled, the sampling instrument and the containers for samplesfrom avdentitious contamination.

.’ 3.

+.__.L ~.

.^v’; ;q

i

ISr7966-1976

El.3 To draw a representative sample, the contents of each containerselected for sampling shall be mixed thoroughly.

El.4 The samples shall be placed in clean, dry, airtight glass or othersuitable containers.

B-l.5 Each sample container shall be sealed airtight with a suitablestopper after filling, and marked with full details of sampling, the dateof sampling and the year of manufacture of the material.

B-2. SCALE OF SAMPLING

B-2.1 Lot - All the containers in a single consignment of the material ofthe same type, same size and belonging to the same batch of manufac-ture shall constitute a lot. If a consignment is declared or known toconsist of different batches of manufacture, the containers belonging tothe same batch shall be grouped together and each such group shallconstitute a separate lot.

B-2.1.1 Samples shall be tested from each lot for ascertaining wnfor-mity of the material to the requirements of the specification.

B-2.2 The number of containers (rz) to be selected from the lot shalldepend on the size of the lot (Jv) and shall be as given in Table 2.

TABLE 2 NUMBER OF CONTAINERS TO BE SELECTEDFOR SAMPLING

LOl! SIZE No.orC0m~uvmw To BZS E L E C T E D

fl n

(1) (2)

up to 50 351 ,, 200 4

201,) 400 54Ql ,, 650 6651 ,, 1 000 7

1001 and above 8

B-2.3 The containers shall be selected at random from the lot and inorder to ensure the randomness of selection, the random sampling *methods given in IS : 4905-1968* may be followed.

*Methods for random sampling...L_

IS : 7966 - 1976

B-3. TEST VMPLES AND REFEREE SAMPLE

B-3.1 Preparation of Test Samples

B-3.1.1 Draw with an appropriate sampling instrument small portionof the material from different parts of each container selected (seeTable 2). The total quantity of the material drawn from each selectedcontainer shall be thrice the quantity required to conduct the tests for allthe characteristics given under 3.

B-3.1.2 Thoroughly mix all portions of the material drawn from thesame container. Out of these portions, small but approximately equalquantities shall be taken from each selected container and shall be wellmixed up together so as to form a composite sample. The composite

‘sample shall be divided into three equal parts, one for the purchaser,another for the supplier and the third for the referee.

B-3.2 Referee Sample -The referee sample shall consist of a compositesample marked for this purpose and shall bear the seals of the purchaserand the supplier. It shall be kept at a place agreed to between the pur-chaser a.nd the supplier and shall be used in case of dispute between thetwo.

B-4. NUMBER OF TESTS

B-4.1 Tests for all the characteristics given in 3 shall be conducted on thecomposite sample. _‘.

B - 5 . C R I T E R I A F O R C O N F O R M I T Y

B-5.1 The lot shall be declared as conforming to this specification if thecomposite sample satisfies the requirements for each of the characteristicsgiven in 3. If the requirements for any of the characteristics are notmet, the lot shall be declared to have not satisfied the requirements ofthe specification.