Microsoft Word ISO 4823 E doc Reference number ISO 4823 2000(E) © ISO 2000 INTERNATIONAL STANDARD ISO 4823 Third edition 2000 12 15 Dentistry — Elastomeric impression materials Art dentaire — Produits[.]
Component colours
Different components intended for use in the same mixture shall be supplied in contrasting colours to provide a means of determining when the components have been thoroughly mixed.
Mixing time (hand-spatulated or hand-kneaded mixes)
When combining impression material components as per the manufacturer's instructions in section 10.3 e), the mixing process should be monitored to ensure it results in a homogeneous, streak-free mixture The average time required to achieve this consistent consistency must not exceed the time specified by the manufacturer in section 10.3 e) Proper evaluation of the mixing results in accordance with section 9.1 is essential to maintain quality and adherence to standards.
Working time
According to section 9.3, the working time must meet or exceed the duration specified by the manufacturer’s instructions in section 10.3 f) Additionally, the working time should be at least 30 seconds longer than the time needed to achieve a homogeneous mix, as outlined in sections 6.2 and 9.1 Proper adherence to these guidelines ensures optimal mixing and application performance.
Compatibility with gypsum
The impression material shall impart a smooth surface to, and separate cleanly from, the gypsum model material poured against it (see Table 1).
Table 1 — Additional characteristic and physical property requirements
Test subclause No and description
Type min max mm max mm min min max.
3 36 — 20 1,5 50 96,5 2,0 20 a The line reproduction shall be considered satisfactory if the required line a, b, or c is continuous between the lines d 1 and d 2 See test block in Figure 12.
NOTE Requirements for information to be included in the manufacturer's instructions for use, packaging and labelling are listed in clauses 10 and 11.
Samples of materials to be tested shall be procured from a single manufacturing batch as packaged for retail marketing.
A typical volume of approximately 900 ml of the mixed material is sufficient to perform all necessary tests and allows ample practice for the test operator to achieve proficiency in specimen preparation and testing procedures Ensuring adequate material volume supports accurate testing and skill development, contributing to reliable results and improved operator expertise.
Before opening any packaging, thoroughly review the labeling to ensure compliance with clause 11.2 and to identify any necessary precautions for safe use and storage Additionally, inspect the instructions on the immediate container to confirm conformity with clause 10 before proceeding.
Laboratory conditions
For all specimen preparation and testing, unless specified otherwise in this International Standard, ensure conditions are maintained at ambient laboratory temperature of (23±2) °C and relative humidity of (50±10) % Prior to use, bring all equipment and materials to these ambient conditions to ensure accurate and consistent testing results.
Apparatus function verification
Before using any accessories, instruments, or equipment, thoroughly inspect them to confirm they are in acceptable working condition Perform all necessary calibration procedures to ensure they meet the specified standards and comply with the requirements outlined in this International Standard or any referenced normative documents.
Material manipulation and specimen preparation
When preparing and manipulating test materials, always follow the manufacturer’s instructions and use recommended equipment and procedures For hand-mixed materials, employ mass/mass proportioning of ingredients and ensure manual kneading is performed with gloves or non-reactive polymer sheeting to prevent altering the material’s properties Prepare a minimum of 15 ml of material per specimen, sufficient for a medium-sized arch impression Additionally, accurately time specimen preparation and testing procedures using precise timing devices like a stopwatch.
Pass/fail determinations
The minimum number of specimens required for pass/fail determinations is either three or five, depending on the testing procedure For a three-specimen minimum, if at least two specimens meet the requirements, the material passes; if none do, it fails; and if only one complies, three additional specimens are tested, with all three needing to pass for the material to succeed For a five-specimen minimum, at least four out of five specimens must meet the criteria for a pass; if only one or two comply, it fails; and if three do, an additional five specimens are tested, requiring all to pass for the material to pass.
Expression of test results
Report the number of specimens tested, the number complying with the specified requirement and whether the material passes or fails.
Mixing-time test
9.1.2 Specimen preparation and test procedure (five specimens)
To ensure consistent sample preparation, proportion and mix the required volume of material (8.3) for each specimen, recording the time taken to achieve a homogeneous mixture This process should be repeated for five specimens to ensure accuracy After completing all samples, calculate the mean of the mixing times to determine an average value, which is essential for standardized procedures and reliable results in subsequent testing or analysis.
NOTE Mixes made for this test may be used to provide increments of material needed for the consistency test (9.2)
9.1.3 Pass/fail determination and expression of results
Determine whether the mean result obtained in accordance with 9.1.2 complies with 6.2 and report the results.
Consistency test
9.2.1.1 Two glass plates, one to serve as a base plate, and one to serve as a loading plate (Figure 2).
Dimensions for the loading plate shall be approximately 60 mm by 60 mm and at least 3 mm thick Dimensions of the base plate may be greater.
9.2.1.2 Material delivery system, such as the one illustrated in Figure 1, for delivering a volume of (0,5±0,02) ml of the material onto the base plate.
9.2.1.3 Polyethylene sheets, wrinkle-free, approximately 60 mm by 60 mm and 0,035 mm thick (one per specimen).
9.2.1.4 Polyethylene sheet discs, approximately 10 mm in diameter and 0,035 mm thick (two per specimen).
9.2.1.5 Elastomeric plug, for forming the floor of the test increment-containing cavity.
9.2.1.6 Test instrument for applying a force of (14,7±0,1) N (Figure 2).
The mass of the glass loading plate shall be included as part of the test load.
NOTE The dial indicator illustrated as a part of the test instrument in Figure 2 plays no part in the consistency test.
9.2.1.7 Linear measuring instrument, accurate to 0,5 mm, for measuring diameters of the test specimen disc (9.2.3).
Accomplish the following steps before beginning any of the test procedures: ắ adjust the test instrument (9.2.1.6.) so that the contact surface of the loading shaft foot can descend within
Apply a 5 mm thick layer to the top surface of the instrument base Cover the base plate's top surface with a polyethylene sheet, securing it in place with a thin film of silicon grease on the bottom of the loading plate Use the depth-gauge end of the plunger to push the elastomeric plug into the tapered end of the dispensing tube to the specified depth, ensuring proper seating with the stop Then, use the same end of the plunger to position two polyethylene sheet discs over the cavity floor formed by the plug, ensuring a proper seal for the test.
9.2.3 Specimen preparation and test procedure (3 specimens)
To ensure accurate testing, slightly overfill the cavity in the dispensing tube with the mixed material and remove excess to form the test increment immediately after mixing Next, press the plunger to extrude the test increment along with any polyethylene discs onto the center of the base plate, avoiding separation of the discs from the test increment Carefully center the test increment on the base of the test instrument directly beneath the loading-shaft foot, then place and hold the glass loading plate in contact with the shaft foot Finally, allow the 14.7 N load to gradually descend onto the test increment to complete the procedure.
To obtain a more uniformly circular specimen disc, keep the glass plates as parallel as possible during loading and keep rotation of the plates to a minimum.
Allow the total load to rest on the specimen-forming assembly for 5 s Lift the foot of the loading shaft from contact with the loading plate and allow the assembly to remain at room temperature for at least 15 min Then separate the loading plate from the assembly so as to leave the specimen on the base plate Use the measuring instrument (9.2.1.7) to make two diametral measurements of the specimen, one across the major diameter of the disc and one across the minor diameter Report the average of the two measurements as the diameter to be considered when determining whether the specimen complies with the diameter requirement specified in Table 1.
9.2.4 Pass/fail determination and expression of results
Working-time test
9.3.1.1 Working-time test instrument, including the parts illustrated in Figure 3 through to Figure 10, as well as the three electronic components listed immediately below.
9.3.1.2 Linear variable displacement transducer (LVDT), having a linear working range > 12,5 mm The transducer shall be passive, i.e not spring-loaded.
9.3.1.3 DC power supply, (+ 15 V and-15 V regulated), for modulating the LVDT signals.
9.3.1.4 Chart recorder, compatible with the LVDT and associated equipment.
9.3.2 Pretest instrumentation function verification and assembly
Before using the test instrument (9.3.1.1), use the following procedure to determine whether the friction between the bearing areas of glide track (Figure 5) and the sliding polymer blocks (Figure 7) is within acceptable limits (see also Figure 3): ắ do not use lubricants in attempts to reduce friction; ắ detach the LVDT core carrier rod (Figure 3) from the polymer block 4 L ; ắ clean and dry the bearing surfaces of the sliding blocks and glide track and examine them for defects that can be detected by touch (burrs, nicks, etc.) Eliminate any such defects; ắ seat the sliding blocks in the glide track, and use the perforated test plate (Figure 8) and the plate aligning and locking pins, Parts 5 L and 5 R (Figure 3 and Figure 9) to relate the parts as for testing; ắ elevate one end of the instrument so that the base is at an approximate 20° angle to horizontal; ắ move by hand the sliding block/perforated test plate assembly in the glide track to the upper extreme position and release it immediately.
If the assembly moves freely to the lower extreme position under the pull of gravity, the friction is within acceptable limits.
Repeat the steps described above, with the opposite end of the instrument elevated, to determine whether freedom of movement in the opposite direction is also acceptable.
If friction cannot be minimized through removal of burrs and contaminants, resurfacing the bearing areas may be necessary This process helps eliminate binding interferences that contribute to excessive friction, ensuring smoother operation and improved performance Proper resurfacing is essential when initial cleaning methods fail to reduce friction to acceptable levels.
Upon achieving acceptable limits for friction, remove the test plate, reattach the core carrier rod to the sliding block
4 L in Figure 3 and proceed with assembly of the instrumentation.
Connect the LVDT (9.3.1.2) to the recorder (9.3.1.4) via the power supply (9.3.1.3) to ensure proper signal transmission Adjust the LVDT body position to establish an accurate body/core relationship, allowing a full-scale deflection of the recorder pen to correspond to a rheometer displacement of 3.5 mm Verify that the recorder pen movement accurately reflects a linear relationship with the rheometer displacement for precise measurements and reliable data.
Begin timing the mixing process (9.3.1.6) when starting hand-mixed materials; delay timing for extrusion mixed materials until components enter the mixing nozzle After mixing, within 55 seconds, deposit approximately 2 ml of material on the test specimen pedestal, then press the perforated test plate into the material until it contacts the polymer blocks and extrudes through at least 28 perforations Align the locking pin holes and insert pins to secure the setup, and zero the chart recorder before starting the test.
For materials with a stated working time of 3 minutes or less, initiate testing between 60 to 90 seconds after mixing begins For materials with longer working times, start testing 2 minutes before the specified working time ends During testing, apply finger pressure or controlled force to the sliding block (4 R) to displace the assembly by 0.25 mm, as shown on the chart recorder Immediately remove the force after displacement and observe the recorder’s pen behavior to assess material flow and setting characteristics.
Repeat the displacement procedure every 15 seconds until the chart recorder pen (Figure 11) shows that the specimen displays initial elastic properties, which may negatively impact impression quality.
The chart recorder reading taken 15 seconds before the first indication that the specimen begins to show elastic properties marks the end of the effective working time This measurement is crucial for accurately determining the interval during which the specimen maintains its working conditions Properly recording this point ensures compliance with testing standards and reliable analysis of material performance.
9.3.4 Pass/fail determination and expression of results
Detail reproduction test
9.4.1.1 Test block (Figure 12) and ring mould accessory (Figure 13) Clean the test block ultrasonically before each use.
9.4.1.2 Oven, set at (35±1) °C, for dry heat conditioning of the test block prior to use.
9.4.1.3 Flat glass or metal plate, approximately 50 mm by 50 mm and at least 3 mm thick.
9.4.1.4 Polyethylene sheets, approximately 50 mm by 50 mm and 0,035 mm thick (one per specimen).
9.4.1.5 Water bath, for maintaining a temperature of (35±1) °C in simulation of a mouth temperature environment.
9.4.1.6 Microscope, equipped for´4 to´12 magnification and low angle illumination.
Before mixing the material for each of the three specimens, place the test block and ring mould (9.4.1.1), in the oven (9.4.1.2) for conditioning for at least 15 min.
Cover the underside of the glass or metal plate (9.4.1.3) with a polyethylene sheet (9.4.1.4).
NOTE 1 A thin film of silicone grease spread over the plate will help secure the polyethylene sheet to the plate during specimen formation.
Within 60 seconds after mixing, remove the test block and ring mould from the oven and seat the ring mould on the test block to form the specimen cavity Introduce enough mixed material to slightly overfill the cavity along one side, allowing it to enter the scribed lines (a, b, and c) on the test block and flow to their opposite ends under pressure Use a polyethylene-covered plate to press down and expel excess material from the mould After 60 seconds, immerse the specimen assembly in a water bath for the manufacturer’s recommended duration to set the impression in the mouth.
After completing the water bath treatment, carefully remove the impression material specimen from the ring mold and rinse its surface with distilled or deionized water Gently dry the specimen with a stream of clean air to eliminate residual moisture The resulting lines on the specimen will appear as positive copies—raised lines—mirroring the scribed lines on the test block surface, ensuring accurate replication for analysis.
When testing elastomeric impression materials that may stick to the test block, it is recommended to treat the lined surface with an anti-adherent substance However, care must be taken to ensure that the anti-adherent does not react with the test specimen or test block, as such reactions could lead to undesirable test results.
Immediately after blowing moisture from the specimen, use the microscope (9.4.1.6) to examine the specimen for compliance with the related requirement shown in Table 1.
Variations in the colors of materials may require the use of different light intensities or color filters during specimen examination Adjusting lighting conditions is essential to accurately assess whether the desired lines are correctly reproduced on impression material surfaces and gypsum specimens Proper visualization ensures compatibility testing with gypsum is reliable and precise.
Specimens found to be in compliance with the related requirements for this test can be used for the linear dimensional change test (9.5).
9.4.4 Pass/fail determination and expression of results
Linear dimensional change test
9.5.1.1 Detail reproduction test specimens, made according to 9.4.2, examined according to 9.4.3, and found to be in compliance with the related requirement specified in Table 1.
9.5.1.2 Glass plate approximately 50 mm by 50 mm, and at least 3 mm thick (one for each specimen).
9.5.1.4 Measuring microscope, accurate to 0,01 mm, equipped for ´4 to ´12 magnification, low angle illumination, and a measuring travel of at least 27 mm.
9.5.2 Test block line-length measurement procedure
9.5.2.1 Test block preparation and positioning
To prepare and position the test block, first clean it ultrasonically before starting the procedure Next, position the test block on the microscope stage with line d1 on the right and line c as the lower line, as shown in Figure 14a Ensure the X-axis of the microscope crosshair is parallel to, and approximately 0.03 mm below, line c, aligning as illustrated in Figure 14c, which helps position the Y-axis parallel to lines d1 and d2 Finally, adjust the microscope slide or stage to move the Y-axis of the crosshair at least 0.1 mm outside and to the right of line d1 on the test block.
9.5.2.2 Test block line-length measurement steps
To ensure accurate measurements, after positioning the test block according to step 9.5.2.1, do not reverse the microscope slide or stage direction until all final measurements between lines d₁ and d₂ are completed First, align the left edge of the Y-axis crosshair with the inner edge of line d₁, stop movement, and record this as the initial measurement Next, move the same edge to align with line d₂, stop, and record the final measurement Calculate the difference between these two readings and perform two additional measurements of the distance between lines d₁ and d₂ Average all three measurements to determine and record the final value, L₁.
Apply talcum powder to dust the underside of each detail reproduction test specimen and the top surface of the glass plate Carefully seat the dusted specimen onto the dusted plate, creating a clean and dust-free contact interface Store this assembled setup in the laboratory environment until the designated measurement time outlined in section 9.5.4.1.
Specimens should be measured according to the manufacturer’s recommended time lapse between impression removal and gypsum pouring If the manufacturer allows a delay of 24 hours or more, measurements should be taken 24 hours after separation from the impression Conversely, if the maximum permissible delay is less than 24 hours, specimens must be measured at the end of that specified time frame These guidelines ensure accurate and standardized timing for specimen measurement in accordance with manufacturer instructions.
Follow the procedure outlined in section 9.5.2.2 to measure the distance between lines d₁ and d₂ along line c on the specimen For accurate results, position the specimen on the microscope stage with line d₂ placed to the right initially, ensuring line c appears as the lower line, as shown in Figure 14b Record this measurement as L₂.
Calculate the percentage of dimensional change,DL, for each specimen to the nearest 0,05 %, using the equation
L 1 is the distance measured between lines d 1 and d 2 on the test block (9.5.2.2); and
L 2 is the distance measured between lines d 2 and d 1 on the impression material specimen (9.5.4.2).
Report whether the percentage of change for each specimen complies with the pertinent requirement specified in Table 1.
9.5.4.4 Pass/fail determination and expression of results
Test for compatibility with gypsum
9.6.1.1 Detail reproduction test specimens, made according to 9.4.2, examined according to 9.4.3, and which have been found to be in compliance with the related detail reproduction requirement shown in Table 1.
9.6.1.4 Slit mould(Figure 13) with a mechanism such as a worm gear clamp for closing the slit.
Using a slit mould requires securely clamping it to keep the slit closed during gypsum specimen formation, then releasing the clamp to open the slit for easy specimen removal The brass alloy employed for the mould should possess a high strain-at-elastic-limit, enabling repeated closing and opening without significant permanent deformation of the slit.
9.6.1.5 Flat glass or metal plate, approximately 50 mm by 50 mm and at least 3 mm thick.
9.6.1.6 Two dental gypsum products[see 10.3 i) and ISO 6873]: ắ one Type 3, dental stone, model and, ắ either one Type 4 or one Type 5, dental stone, high strength.
Gypsum products must be evaluated for compliance with the initial setting time as specified in ISO 6873 before their intended use in testing Non-compliant products should not be used for the test After opening, the products should be stored in sealed containers to prevent moisture contamination and ensure their integrity during use.
9.6.1.7 Mould release agent, such as silicone grease, which will be non-reactive with the slit mould (9.6.1.4) and the gypsum products.
Prepare three specimens for each of the two dental gypsum products required for use in the test.
Before conducting the compatibility test with gypsum, ensure the inner surface of the slit mould is coated with a thin film of mould release agent and securely closed using the clamping mechanism Next, position the specimen in the ring mould, press the riser against the underside of the specimen to ensure its lined surface aligns with the top of the ring mould, then seat the assembly with the riser in place into the slit mould Finally, cover the assembly with a plate and invert the entire setup to prepare for testing.
To ensure proper impression pouring, introduce the first increments of gypsum mixture within approximately 10.3 hours after removal from the mouth, applying mechanical vibration to facilitate flow This initial layer should cover the ends of the raised lines (a, b, and c) on one side of the specimen surface before gradually flowing over the lines toward their opposite ends Subsequently, add enough gypsum mixture to slightly underfill the mould cavity, ensuring an accurate and complete impression.
Store gypsum or impression material assemblies in a controlled laboratory environment until 45 minutes after the initial setting time, unless the manufacturer’s instructions specify otherwise After this period, carefully separate the gypsum specimen from the assembly to ensure optimal results.
Use the microscope (9.6.1.8) to examine the lined surfaces of the gypsum specimen for compliance with the requirements specified in 6.4, and in Table 1 (see also the note in 9.4.3).
9.6.4 Pass/fail determination and expression of results
Elastic recovery test
9.7.1.1 Fixation ring with split mould (Figure 15).
9.7.1.2 Mould release agent, such as silicone grease.
9.7.1.3 Two flat glass or metal plates, approximately 50 mm by 50 mm and at least 3 mm thick.
9.7.1.4 Polyethylene sheets (wrinkle free), approximately 50 mm by 50 mm and 0,035 mm thick.
9.7.1.5 C-clamp, having a minimum screw opening of 40 mm and a minimum throat depth of 30 mm.
9.7.1.8 Small glass or metal test plate, approximately 15 mm by 15 mm and 2 mm thick.
The test instrument, exemplified in Figure 16, features a dial indicator with a precision of 0.01 mm It is designed to work in conjunction with the test plate's weight, as specified in section 9.7.1.8, to apply a total force of (0.59 ± 0.1) N To ensure accurate testing, the stop on the instrument must be set to limit the compression of the test specimen accordingly.
To prepare five specimens, begin by applying a very thin film of the mould release agent to the internal surface of the fixation ring and all surfaces of the split mould Next, cover one surface of each plate with a polyethylene sheet Finally, seat the fixation ring onto one of the polyethylene-covered plates to ensure proper setup for specimen preparation.
After completing the mixing, promptly fill the fixation ring slightly more than halfway Carefully press the split mold halves into the impression material within the fixation ring until their bottom surfaces nearly contact the polyethylene-covered base plate, thereby forcing the material above the top of the mold halves Next, apply pressure with the second polyethylene-covered plate to expel almost all excess material, and secure the plates together using a C-clamp to ensure firm contact with both the top and bottom surfaces of the split mold, all within 60 seconds for optimal results.
Using glass plates (9.7.1.3) instead of metal plates requires the addition of metal backup plates positioned between the glass plates and the C-clamp parts This setup helps to minimize scratching and prevent breakage of the glass plates during installation or maintenance Proper use of backup plates enhances the safety and longevity of the glass components, ensuring secure and damage-free operation Always consider the recommended materials and proper cushioning when working with glass plates to maintain their integrity and performance.
At 60 s after completion of mixing, place this specimen-forming assembly in the water bath (9.7.1.6) for the time specified in the manufacturer's instructions for leaving impressions in the mouth [10.3 g)].
After completing the water bath storage, carefully remove the specimen from the split mold within 40 seconds Place a glass or metal test plate (9.7.1.8) on top of the specimen, then position the entire assembly onto the test instrument base (9.7.1.9), ensuring it is centered and properly aligned with the dial indicator spindle for accurate measurement.
Perform the test according to the specified schedule: at +45 seconds, gently position the dial indicator contact point on the test specimen; at +55 seconds, record the initial reading (ash 1); at +60 seconds, deform the specimen by (6 ± 0.1) mm within 1 second, then release the force gradually over 5 seconds, and lift the contact point from the specimen; at +170 seconds, carefully reapply the contact point to the test surface; and at +180 seconds, record the final dial indicator reading (ash 2).
To minimize lateral displacement of the specimen during the application of deforming force, it is recommended to cement an abrasive paper covering, approximately 600 grit (FEPA 1200), onto the instrument base and test plate surfaces This enhances grip and stability, ensuring accurate test results.
Calculate the percentage of elastic recovery,K, for each specimen, using the equation:
The height of the split mold is denoted as h₀ The dial indicator reading at t + 55 seconds, just before the specimen undergoes deformation, is recorded as h₁ After the deforming force is removed, the dial indicator reading at t + 180 seconds, which is 115 seconds post-deformation, is recorded as h₂ These measurements are essential for analyzing the deformation behavior of the specimen over time.
Discard defective specimens identified through axial sectioning into eight equal segments Examine each segment meticulously for defects like air inclusions to ensure specimen quality Properly removing defective samples enhances the accuracy and reliability of your analysis.
9.7.5 Pass/fail determination and expression of results
Strain-in-compression test
Items listed in 9.7.1.1 through 9.7.1.7 are required for preparing the specimen, together with a test instrument, such as the one shown in Figure 2 The dial indicator shall be accurate to 0,01 mm.
Prepare five specimens according to the procedure described in 9.7.2, with the exception that the test plate (9.7.1.8) is not placed on the specimen.
Immediately after removing the specimen from the water bath, place it on the test instrument's base, centered below the loading shaft Conduct the test following a specified time schedule: at 60 seconds, lower the loading shaft onto the specimen to apply an initial load of approximately 1.22 N; at 90 seconds, lock the shaft, position the dial indicator on top of the shaft, and record the initial dial reading; at 95 seconds, remove the dial contact, unlock the shaft, and gradually increase the load to 12.25 N over 10 seconds; at 135 seconds, lock the shaft again, reposition the dial indicator, and record the final reading.
Calculate the percentage of strain-in-compression,E, for each specimen, using the equation:
The article discusses measurements related to split mold testing, where h₀ represents the height of the split mold, h₁ is the dial indicator reading taken 30 seconds after applying the initial load, and h₂ is the reading recorded 30 seconds after the full increased load has been applied These measurements are essential for assessing material deformation and ensuring accurate test results Properly documenting h₀, h₁, and h₂ helps in evaluating the material's response under different load conditions, which is crucial for quality assurance and compliance with testing standards.
Examine any failing specimens according to the procedure described in 9.7.4.
9.8.5 Pass/fail determination and expression of results
10 Requirements for information in manufacturer's instructions
General
Each retail package containing impression material components must include clear instructions and essential information to guarantee optimal clinical performance Providing comprehensive guidance ensures practitioners can effectively utilize the material, enhancing patient outcomes Proper labeling and instructions are crucial for maintaining quality and safety in dental practices.
Identifying information
To ensure proper identification, please provide the trade or brand name of the product Additionally, specify the chemical nature of the elastomeric system, such as whether it is a polyether, polysulfide, silicone (condensation type), or silicone (vinyl polysiloxane, addition type) Including this information is essential for accurate classification and compliance with quality standards.
Specific instructions for use
When using dental impression materials, incorporate clear instructions covering storage conditions after opening, noting that factors such as room temperature variations, mixing speed, hand/fingertip temperatures, moisture contamination, and contact with latex or gloves can significantly impact working time and material characteristics Specify proportions for hand-spatulated mixes and recommend appropriate mixing apparatus and procedures, including using gloves or polymer sheeting to prevent contamination Include details on the necessary mixing time to achieve homogeneity for a 15 ml volume, as well as working time, minimum impression removal time, and acceptable time intervals between impression removal and gypsum pouring Identify at least two compatible gypsum products, such as ISO 6873-compliant Type 3 and Type 4 or 5, for use with the impression material For disinfection, provide detailed procedures when applicable, emphasizing that disinfection should not compromise impression performance Additionally, if a material is claimed to be antimicrobial, specify the supporting reference demonstrating that the effect persists post-removal.
11 Requirements for packaging and labelling
Packaging requirements
This International Standard does not specify packaging requirements; however, manufacturers must ensure that packaging prevents contamination of the material components during storage The containers should be designed to avoid leakage or accidental extrusion of contents, maintaining integrity throughout storage and use Additionally, packaging must withstand the recommended extrusion methods without rupturing, ensuring safety and product quality during handling and application.
Labelling requirements
11.2.1 Outer packages (containing one or more primary containers)
Packaging labels for retail products must clearly display essential information, including recommended storage conditions for unopened packages, brand name, manufacturer details or authorized distributor, and the material’s consistency type (such as putty or light-bodied), optionally including the type number Additionally, labels should feature batch reference numbers and a prominently displayed "USE BEFORE" date, formatted as a six-digit code (e.g., 2001-09) indicating the expiry or best-use period of the material These labeling requirements ensure proper product handling, traceability, and consumer safety.
(2001) and the last two digits indicate the month (September); g) the minimum volume that would result from mixing the entire component contents included in the outer package.
11.2.2 Primary containers within outer packaging
Primary container labels must include essential information such as the brand name, the manufacturer’s or authorized company's name responsible for marketing the material under a different brand, component identification (except when components are supplied together in the same primary container for extrusion mixing), and the manufacturer’s batch reference to ensure product traceability and compliance.
Dimensions in millimetres a) Dispensing tube a b) Depth gauge/specimen increment-extruding plunger b
1 Cavity equal in volume to the volume of the increment of material [(0,5±0,02) ml] needed for the test
2 Elastomeric plug for forming the floor of the cavity
3 Depth gauge for positioning the plug
5 Increment-extruding end of plunger
Other dimensions may be used when manufacturing these parts, provided that the dispensing tube bore and the depth gauge are properly mated to create a cavity with a volume of (0.5 ± 0.02) ml Additionally, the lengths of the plug and the extruding end of the plunger must enable complete extrusion of the specimen from the cavity, ensuring accurate and consistent testing results.
The elastomeric plug is created by forming approximately 1 ml of heavy-bodied elastomeric impression material within the bore of the dispensing tube The dispensing tube is constructed from durable materials such as PTFE (polytetrafluoroethylene) or acetal, ensuring chemical resistance and ease of use The plunger used to dispense the material is fabricated from rigid metals or high-strength polymeric materials, providing reliable control during application.
Figure 1 — Delivery system for consistency test specimen material
2 Weight having a mass which, along with the masses of items 3, 4 and 6, will provide for the total force of (14,7±0,1) N needed for the consistency test
3 Weight having a mass which, along with the mass of item 4, will provide for the total force of (12,25±0,1) N needed to complete the strain-in compression test
4 Loading shaft, complete with weight support, having a mass that will provide for the initial force of (1,22±0,1) N needed for the strain-in compression test
Figure 2 — Instrument for consistency and strain-in-compression tests
5 5 L and 5 R : plate aligning and locking pins
The position of the LVDT to the left of other components facilitates right-handed use of the instrument, while reversing this arrangement—attaching the core carrier rod to sliding block 4 R—enhances suitability for left-handed users The components supplied by the LVDT manufacturer ensure reliable performance, with parts crafted from durable stainless steel and anodized aluminium to optimize durability and corrosion resistance This ergonomic and high-quality design supports precise and comfortable operation for users of all preferences.
Figure 3 — Working-time test instrument assembled
Dimensions in millimetres a Distance between centres of the two LVDT supports This dimension may vary depending upon the length of the LVDT used.
Figure 4 — Instrument base — Working-time test instrument
Dimensions in millimetres a Indicates bearing surfaces of the glide track.
Figure 5 — Glide track — Working-time test instrument
Dimensions in millimetres a Ten slots with centres 3 mm apart.
Figure 6 — Slotted specimen test pedestal — Working-time test instrument
1 Hole sized and threaded in one of the blocks to accommodate the thread of the core carrier rod
2 Cheese-head screws, M2,5 stainless steel (6 places)
3 Main body of block made of polyacetal
4 Lateral bearing surface made of PFTE
5 Hole to accommodate test plate aligning and locking pin
Figure 7 — Sliding polymer block — Working-time test instrument
Dimensions in millimetres a Letter R marked in the top surface for use in positioning the test plate.
Figure 8 — Perforated test plate — Working-time test instrument
Figure 9 — Test plate aligning and locking pin — Working-time test instrument
1 Cap-head screws, M4,5 stainless steel a Dimension accommodating an LVDT with an outside diameter of about 20,5 mm The dimension varies according to the outside diameter of the LVDT.
Figure 10 — LVDT support — Working-time test instrument
3 First indication of development of elastic property d LVDT core displacement t Time
Figure 11 — Example of a working-time test chart tracing
NOTE 1 Unless otherwise specified, dimensions are in millimetres.
NOTE 2 Unless otherwise specified, tolerances are ±0,1 mm; surface roughness is 3,2mm max and material is cast or wrought austenitic stainless steel.
NOTE 3 Lines d 1 and d 2 are the same width as line c.
Figure 12 — Test block for detail reproduction and tests for compatibility with gypsum
Dimensions in millimetres a) Ring mould b b) Riser b c) Slit mould c
1 Cut-out approximately 1 mm deep
2 Rim of recess in slit mould
3 Width of slit before it is closed a Internal diameter of the mould after the clamping mechanism closes the slit. b Made of polymer, brass or stainless steel. c Made of brass.
Figure 13 — Accessories for detail reproduction and tests for compatibility with gypsum
Dimensions in millimetres a) Position of lined block b) Position of impression material specimen c) Relationship between lines on test block and microscope cross-hair positions
5 Position ofXandYmicroscope cross-hairs for first measurement
6 Position of cross-hairs for second measurement
Figure 14 — Linear dimensional change test — Positions of lined test block and impression material specimens on microscope stage for measurements between lines d 1 and d 2
1 Cut-out approximately 1,0 mm wide, 1,0 mm deep in two places
4 Split mould, two halves, no bell mouth in bore
NOTE 1 Surface texture is 3,2mm max unless otherwise specified.
NOTE 2 Components are made of anodized aluminium, brass or stainless steel.
Figure 15 — Split mould for forming specimens — Elastic recovery and strain-in-compression tests
1 Lever for compressing the specimen
Figure 16 — Elastic recovery test instrument
Working-time test instrument components — Possible sources
This annex outlines the sources for the working-time test instrument (9.3.1.1) and the linear variable displacement transducer (LVTD) (9.3.1.2) Both LVDT options provided below comply with the specifications outlined in section 9.3.1.2, ensuring suitability for accurate measurement and testing purposes.
The working-time test instrument, excluding the LVDT component and other accessories, can be manufactured by any capable machining facility equipped with the necessary tools and expertise It must be built in accordance with the detailed specifications provided in Figures 3 through 10 of this International Standard, ensuring compliance and quality in production.
Working-time test instrument (exclusive of the LVDT component and other accessories identified in the text).
Dental School, University of Newcastle
Newcastle upon Tyne NE2 4BW
Heath Town, Wolverhampton, Staffs WV10 OPY
1) This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of the products named.
[1] ISO 7405, DentistryắPreclinical evaluation of biocompatibility of medical devices used in dentistryắTest methods for dental materials.
[2] ISO 10993-1, Biological evaluation of medical devicesắPart 1: Evaluation and testing.