YY 1042-2003 Polymer-based filling, restorative and cementing materials in dentistry
Some standard content:
ICS 11. 060. 10
Pharmaceutical Industry Standard of the People's Republic of China
YY1042—2003
Replaces YY91042—1999
Dentistry-Polymer-based filling, restorative and luting materials materials（ISO4049.2000,MOD）
Published on June 20, 2003
State Food and Drug Administration
Implemented on January 1, 2004
Dentistry
Medicine of the People's Republic of China
Industry standard
Polymer-based filling, restorative and cementing materials YY1042--2003
Published by China Standards Press
No. 16, Sanlihe North Street, Fuxingmenwai, Beijing
Postal code: 100045
Tel: 68523946
68517548
Printed by China Standards Press, Qinhuangdao Printing Factory, Xinhua Bookstore, Beijing Distributed by
Sold by Xinhua Bookstores in all regions
880×1230
Printing sheet 1%
Word count 42,000 words
First printing in January 2004
First edition in January 2004
Print runs 1-1000
Book number: 155066·2-15416
Price 14.00 yuan
Website bzcbs.com
Copyright reserved
Infringements must be investigated
Report telephone number: (010) 68533533
This standard is modified to adopt ISO4049:2000 "Textbook standard for dentistry". The main differences from this international standard are as follows: "Foreword" and "Introduction" have been deleted.
YY1042—2003
Polymer Matrix Filling, Restoration and Cementing Materials" (English version). The introductory words of the normative reference documents adopt the relevant parts of GB/T1.1—2000 to replace the corresponding contents in ISO4049. According to the principle of "normative reference documents are normatively referenced in the standard", since ISO8601:1988 is not normatively referenced in this standard, it is not included in the normative reference documents in this standard. Delete "ISO3696:1987" in "normative reference documents". In this standard, "distilled water or deionized water" replaces the "grade 2 water" cited in "ISO3696:1987". In the references, "ISO7405:1997" is replaced by YY/T0268-2001 "Dentistry - Preclinical evaluation of biocompatibility of medical devices for oral use - Unit 1: Evaluation and test item selection", and "ISO10993-1" is replaced by GB/T16886.12001 "Biological evaluation of medical devices - Part 1: Evaluation and testing". In "8 Requirements for labels, signs, packaging and instructions provided by manufacturers", "8.4 Chinese signs should comply with the provisions of national laws and regulations" is added.
The chapter title of "7 Test methods" is changed to "7 Test methods and inspection rules". The main changes between this standard and YY91042-1999 Dental Composite Resin Filling Materials are as follows: The name of the standard is changed from "Dental Composite Resin Filling Materials" to "Polymer-based Filling, Restoration and Cementing Materials." - The maximum water absorption value in the original standard is 50#g/mm, and the maximum water absorption value in the revised standard is 40μg/mm. The maximum solubility value in the original standard is 5ug/mm, and the maximum solubility value in the revised standard is 7.5μg/mm. The requirements and test methods of "cementing materials" and their "film thickness" are added to the standard scope. "X-ray blocking performance" is added to the requirements and test methods of filling and restorative materials. The contents of "inspection rules" and "test methods" are combined into one chapter, and the chapter title is "test methods and inspection rules". Appendix A of this standard is an informative appendix.
This standard is proposed by the State Food and Drug Administration. This standard is under the jurisdiction of the National Technical Committee for Standardization of Dental Materials and Instruments. This standard is drafted by the Peking University Medical Device Quality Supervision and Inspection Center of the State Food and Drug Administration. The main drafters of this standard are Liu Wenyi and Zhang Yan. This standard abolishes the previous versions of the standard: GB11747-1989;
YY91042—1999.
1 Scope
Dental polymer-based filling, repair and cementing materials YY1042—2003
This standard specifies the requirements for filling, repair and cementing materials based on polymers for use in dentistry. After being mechanically mixed, artificially mixed or activated by external energy in/outside the mouth, such materials can be used directly or indirectly to repair tooth cavities. The cementing materials covered by this standard refer to materials used for cementing and fixing restorations (such as inlays, onlays, veneers, crowns and bridges, etc.). This standard does not cover resin-based crown and bridge materials (ISO10477) and resin-based pit and fissure sealant materials for caries prevention (ISO6874). 2 Normative references
The following documents, through reference in this standard, constitute clauses of this standard. For dated references, all subsequent amendments (excluding errata) or revisions to such documents are not applicable to this standard. However, parties to agreements based on this standard are encouraged to investigate whether the latest versions of these documents can be used. For undated references, the latest versions apply to this standard. ISO 3665:1996 Photography - Intraoral dental radiographs - Technical specifications ISO 7491:1999 Dental materials - Method for determination of the colour stability of dental materials 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
OpaquerlutingmaterialPolymer-based cementing material that enhances colour, used to conceal the underlying tooth structure. 3.2
Opaque
Light-shielding substance in polymer-based restorative materials used to reduce their transparency. 4 Classification
In this standard, dental polymer-based restorative materials are classified as follows a) Type I: polymer-based filling and restorative materials specified by the manufacturer for use in occlusal repair. b) Type II: polymer-based filling and restorative materials other than Type I. Note: Polymer-based cementing materials are not classified.
Dental polymer-based filling, restorative and cementing materials are classified into the following three categories: Type I: Materials that are cured by mixing initiators and catalysts (self-curing materials). Type II: Materials that are cured by external energy such as blue light and heat (external energy activated materials). They can be further divided into:
1) Group 1: External energy activated materials completed in the oral cavity. 2) Group 2: External energy activated materials completed outside the oral cavity. After production, they are bonded to the repaired part. If the manufacturer specifies that certain materials belong to both Group 1 and Group 2, then the materials should meet the requirements of both groups. Note: Type II cementing materials belong only to Group 1. Class III: Materials that can be cured by external energy and have a self-curing mechanism (dual-curing materials; see 8.3e). YY1042-2003
5 Requirements
5.1 Biocompatibility
See YY/T0268-2001.
5.2 Physical and chemical properties
5.2.1 General requirements
If the manufacturer provides filling and repair materials in multiple shades, each shade, including the masking agent, shall meet the requirements of ambient light sensitivity (5.2.7), curing depth (5.2.8), hue (5.3) and color stability (5.4) of the corresponding model and category of materials. In order to meet the requirements of users, the materials can be tinted and mixed during use. The materials used alone and after tinting and mixing according to the recommended maximum ratio shall meet the requirements [see 8.3d)]. Similarly, if the manufacturer offers multiple shades of cementing material, each shade, including the color cementing material, shall meet all the requirements for depth of cure (5.2.8). Unless otherwise specified by the manufacturer, cementing materials do not need to be tested for color stability (5.4). For the other requirements in 5.2 and 5.5, only one representative shade of cementing, filling and restorative materials needs to be tested. The representative shade can be a material classified by the manufacturer as "universal". If no such classification is available, the shade corresponding to "A3" in the Vita shade classification shall be the representative shade.
5.2.2 Film thickness of cementing material
The film thickness of the cementing material shall not be more than 10μm greater than the value specified by the manufacturer when measured in accordance with 7.5. Regardless of whether the manufacturer specifies the film thickness of the cementing material, the film thickness value shall not be greater than 50μm. 5.2.3 The working time of Class I and Class III filling and restorative materials shall be determined in accordance with 7.6. The working time of Class I and Class III filling and restorative materials shall not be less than 90 seconds. 5.2.4 The working time of Class I and Class III cementing materials shall be determined in accordance with 7.7. The materials shall be able to form a thin layer. During the formation of the thin layer, there shall be no perceptible change in their uniformity. 5.2.5 The curing time of Class I materials
shall be determined in accordance with 7.8. The curing time of Class I filling and restorative materials shall not be more than 5 minutes, and the curing time of Class I cementing materials shall not be more than 10 minutes.
5.2.6 The curing time of Class III materials
shall be determined in accordance with 7.8. The curing time shall not be more than 10 minutes. 5.2.7 The sensitivity of Class I materials to ambient light shall be determined in accordance with 7.9. The materials shall maintain physical uniformity. 5.2.8 Depth of cure of Class II materials
The cure depth of Class II filling and restorative materials specified by the manufacturer as opacifiers shall not be less than 1 mm, as measured in accordance with 7.10, while that of other filling and restorative materials shall not be less than 1.5 mm. The cure depth of cementing materials specified by the manufacturer as opacifiers shall not be less than 0.5 mm, as measured in accordance with 7.10. Other materials shall not be less than 1.5 mm.
The cure depth of cementing materials other than opacifiers shall not be less than 0.5 mm less than the value specified by the manufacturer. 5.2.9 Flexural strength of Type I and Type II materials
The flexural strength of Type I and Type II materials, as measured in accordance with 7.11, shall be equal to or greater than the limit values specified in Table 1. 5.2.10 Water absorption and solubility values
Measured in accordance with 7.12:
a) The water absorption value of all materials shall be less than or equal to 40μg/mm2; b) The solubility value of all materials shall be less than or equal to 7.5μg/mm2. 2
Minimum value of flexural strength
Class II Group 1
Class II Group 2
Class II Group 1
YY1042—2003
100MPa
5.3 Color tone of filling and repair materials
Assessed in accordance with 7.13 and ISO7491, the color tone of the cured material shall be close to the color guide provided by the manufacturer. If the manufacturer does not provide a color guide, a commercially available color guide shall be specified that can be used to assess this requirement [see 8.31)7. In addition, the cured material shall be uniformly colored when observed with the naked eye. 5.4 Colour stability after immersion in water
The colour of the filling and repair materials shall change only slightly when tested in accordance with 7.13 and ISO 7491. The colour stability of cementing materials shall be tested only if the manufacturer requires it. If required, it shall be tested in accordance with 7.13 and ISO 7491 and only slight colour changes are permitted.
5.5 X-ray opacity
If the manufacturer specifies that the material is X-ray opaque [see 8.2.3h)], its X-ray opacity shall be equal to or greater than that of an aluminium plate of the same thickness as the material and shall not be less than 0.5 mm above the value specified by the manufacturer. If there is a dispute as to whether the material meets the requirements, method A (7.14.2, 7.14.3, 7.14.4) shall be used for judgment. Table 2 Physical and chemical properties of filling and repair materials (minimum flexural strength is shown in Table 1) Requirement
Material category
Working time
(5.2.3)/s
Curing time
(5.2.5, 5.2.6)/min
Curing depth
<5.2.8)/mm
1(coloring agent)
1.5(others)
Water absorption value
Dissolution value
(5.2.10)/(ug/mm)(5.2.10)/(μg/mm) Maximum
The values of all materials shall not be less than the values specified by the manufacturer by more than 0.5mm. Table 3 Physical and chemical properties of adhesive materials
Material category
Film thickness
(5.2.2)/μm
Working time
(5.2.4)/s
Curing time
(5.2.5,5.2.6)/
Curing depth
(5.2.8)/mm
0.5 (Opaque adhesive
Material) 1.5 (Others
The test value shall not be greater than the value specified by the manufacturer by 10 um or more. The value of other materials other than color-avoiding adhesive materials shall not be less than 0.5mm or more than the value specified by the manufacturer. Water absorption value
(5.2.10)/
(ug/mrn)
Dissolution value
(5.2.10)/
（gg/mm）
YY1042—2003
6 Sampling
Take sufficient amount of samples required for the test from the retail packaging of the same batch number. If necessary, increase the sample for repeated testing. Note: The sufficient amount should be 50g.
7 Test methods and inspection rules
Items for factory inspection The purpose of determination, items of periodic inspection and periodic inspection shall be determined by the manufacturer according to the quality management system. 7.1 Water
Distilled water or deionized water.
7.2 Test environment
Unless otherwise specified by the manufacturer, all test specimens shall be prepared in an environment of (23±1)°C and relative humidity above 30%. If the material is stored in a refrigerator, it shall be allowed to reach (23±1)°C before testing. The working time (see 7.6) and curing time (see 7.8) of Class III materials shall be carried out under conditions without activation reaction. Both natural light and artificial light in the environment can activate the material. In order to control the light, the test shall be conducted in an environment with a yellow filter. The test specimens shall be carried out in a dark room with a light source filtered by a light sheet. 7.3 Visual observation
Visual observation shall comply with the requirements of Chapter 8.
7.4 Specimen preparation
When preparing specimens of Class II and Class III materials, refer to the manufacturer's instructions [see 8.3e for the light source specified or recommended for use, and ensure that the light source meets the conditions of use.
Mix the materials or prepare the specimens by other methods in accordance with the manufacturer's instructions and the test environment requirements of 7.2. In tests 7.11 to 7.14, the specimens are required to be completely cured. It is very important to ensure that the structure of the specimens removed from the mold is uniform. For this reason, the specimens should not be observed with the naked eye. Pores, cracks and bubbles are produced. Some polymer-based materials, especially some cementing materials, have a chemical affinity with base metals, making it difficult to remove the specimen from the metal mold. Therefore, attention should be paid to the information provided by the manufacturer (see 8.3) on this property. If the material has this property, the mold for preparing the specimen should be made of non-metallic material such as high-density polyethylene. 7.5 Measurement of film thickness of cementing material
7.5.1 Apparatus
7.5.1.1 The contact area between two square or circular optical glass plates should be (200 ± 25) mm, and the thickness of the glass plates should be uniform and not less than 5 mm.
Note: For reusable glass plates, a layer of release agent that has no effect on the film thickness of the material can be applied on the surface. 7.5.1.2 Loading device is shown in Figure 1, or an equivalent device. The device applies a force of (150 ± 2) N vertically to the specimen through the glass plate. The loading head is attached to the bottom end of the loading rod, and its end face is parallel to the base and horizontal. The loading force is uniform and there is no rotation. Note: Use a positioning device to assist in positioning the glass plate. For round glass plates, install 3 vertical positioning pins on the base of the positioning device; for square glass plates, install 4 vertical positioning pins on the base of its positioning device (see Figure 2). 7.5.1.3 Light source (for Class II and Class III materials) shall be in accordance with the light source recommended by the manufacturer for material testing. 7.5.1.4 Dry gauge or equivalent measuring instrument with an accuracy of 1 μm. 7.5.2 Steps
7.5.2.1 Preparatory stage
Use a dry gauge to measure the thickness of the two optical glass plates when they are in close contact with an accuracy of 1 μm (read as A). Remove the upper glass plate and place 0.02mL~0.1mL of the test material prepared according to the manufacturer's instructions on the center of the lower glass plate, and align the loading head with the center of the lower glass plate. Place the upper glass plate on the test material in the original measurement direction. The positioning pins help to position the glass plate (Figure 2). 7.5.2.2 Type I materials
Type I materials are mixed (60±2)s later, and a force of (150±2)N is applied vertically to the center of the sample through the upper glass plate to make the sample completely 4
Sample,
Glass plate.
Figure 1 Loading device for measuring film thickness (7.5) YY1042—2003
Fill the space between the two glass plates and maintain for (180±10)s. At least 10 minutes after the start of blending, remove it from the loading device and measure the total thickness of the two glass plates and the sample film (read as B). Record the difference between reading A and reading B, accurate to 1μm, as the film thickness of the adhesive material. The above test is carried out 5 times in total.
7.5.2.3 Class II and Class III materials
After the Class II material is taken out or the Class II material is blended, immediately apply a force of (150±2)N to the center of the sample in the vertical direction through the upper glass plate so that the sample can completely fill the space between the two glass plates and maintain for (180±10)s. Remove the load and irradiate the sample through the center of the upper glass plate for twice the recommended illumination time. Note: The purpose of irradiation is not to completely solidify the material, but to stabilize the sample for measurement. After irradiation of Class II and Class III materials, remove the glass plate from the loading device and measure the total thickness of the two glass plates and the sample film (read as B).
Record the difference between reading A and reading B, accurate to 1μm, as the film thickness of the adhesive material. The above test is carried out 5 times in total.
YY1042-—2003
The diameter d slightly exceeds the diameter of the glass plate.
The height h of the pin is 1.5 times the thickness of a single glass plate. Figure 2 Glass plate positioning device (7.5.1.2) 7.5.3 Determination of test results
Record the film thickness of the five samples. The test results are determined as follows: If at least 4 values are less than or equal to 50μm, the material is considered to meet the second requirement of 5.2.2. a)
b) If 3 or more values are greater than 50μm, the material is considered to not meet the standard requirements. If only 3 values are less than or equal to 50μm, the test should be repeated. In the second test, if one or more values are greater than 50 μm, the material is considered to be non-compliant with the standard requirements. d) If the manufacturer specifies the film thickness value. If at least four of the five test values are not greater than the specified value by more than 10 μm, the material is considered to meet the first requirement of 5.2.2.
7.6 Working time of Class I and Class III filling and repair materials 7.6.1 Apparatus
7.6.1.1 The thermocouple test apparatus is shown in Figure 3. The apparatus consists of a polyamide (or similar material) base B and a polyethylene tube A (or similar material) installed on it. A stainless steel tube C is installed in the hole of the base B, and a stable thermocouple D is installed in the stainless steel tube. Tube A is 8 mm long, 4 mm in diameter, and 1 mm thick. The diameter of the connecting part of B and A is 4 mm and the height is 2 mm. After AB is combined, a sample slot with a height of 6 mm and a diameter of 4 mm is formed. In order to facilitate the removal of the sample, the top of the thermocouple D is made into a cone shape and embedded in the sample slot by 1 mm. The permissible error of the above dimensions is ±0.1 mm. The thermocouple wire is made of a material (e.g. copper, constantan) with a diameter of (0.2 ±0.05) mm and capable of indicating the temperature change during the curing of the specimen, with an accuracy of 0.1 °C. Connect the thermocouple to an instrument for recording temperature (e.g. voltmeter or recorder). 7.6.2 Procedure
Prepare the test material according to the manufacturer's instructions (see 8.3) and start timing from the time of blending. Keep the above apparatus at an environment of (23 ±1) °C. 30 s after the start of blending, place the blended material in the sample tank, record the temperature of the material to, and continue to record the temperature of the material until the maximum value.
Figure 4 shows a typical recording curve. As soon as the material is placed in tube A, the temperature immediately rises to t, then decreases until it stabilizes at to. The temperature then begins to rise again, and the point where the temperature begins to rise indicates the start of the curing reaction, i.e. the end of the working time. This point can be obtained by making a horizontal baseline from (to ± 0.1)℃. The time corresponding to the intersection of the horizontal baseline and the rising section of the curve is the working time T. The test results are closely related to temperature. A slight temperature change within the allowable temperature range can cause a difference of a few seconds in the test results. The time from the start of blending to the start of temperature rise is recorded as the working time T.
The above test was tested 5 times in total.
-Polyethylene tube;
Polyamide base:
-Stainless steel tube:www.bzxz.net
-Thermocouple cone probe.
-Blending start time;
-Insertion time
Figure 3 Working time and curing time measuring instrument YY1042--2003
Unit is millimeter
Note: This schematic diagram shows the temperature when the galvanic couple is inserted, and t is the temperature at which the temperature rises immediately after the galvanic couple is inserted into the material. The point where the temperature starts to rise is the beginning of the curing reaction, that is, the end of the working time. It is recorded as the working time T. Figure 4 Working time determination curve (7.6.2) YY1042—2003
7.6.3 Test result judgment
a) If at least 4 of the 5 samples are equal to or greater than 90 seconds, the material is considered to meet the requirements of 5.2.3. b) If 3 or more of the 5 samples are less than 90 seconds, the material is considered to not meet the requirements of 5.2.3. c) If only 3 of the 5 samples are equal to or greater than 90 seconds, the test should be repeated. If 1 or more of the results of the second test are less than 90 seconds, the material is considered to not meet the requirements of 5.2.3. 7.7 Working time of Class I and Class III cementing materials 7.7.1 Apparatus
7.7.1.1 2 slides
7.7.1.2 Timer with an accuracy of 1 second.
7.7.2 Procedure
60s after mixing, place a mass of material of about 30mg on the first glass slide (7.7.1.1), and immediately place the second glass slide on the material and squeeze it to form a thin layer. Visually observe whether the material is physically uniform. Note: During the test, cracks and bubbles will appear on the sample when the material begins to solidify. For fast-curing materials, the viscosity increases, which will affect the formation of a thin layer. Repeat the above test twice. Use a new sample for each test. Record the results of the three tests. 7.7.3 Determination of test results
Visually observe that the three samples can maintain physical uniformity and form a thin layer, then the material is considered to meet the requirements of 5.2.4. 7.8 Curing time of Class I and Class III materials
7.8.1 Apparatus for determining the curing time of Class I and Class III filling and repair materials 7.8.1.1 Thermocouple test apparatus See the provisions of 7.6.1.1. 7.8.2 Apparatus for determining the curing time of Class I and Class III cementing materials 7.8.2.1 Thermocouple test apparatus See the provisions of 7.6.1.1. Except that the length of tube A is changed to 6 mm and the height of the sample groove is 4 mm, the other dimensions are the same as those specified in 7.6.1.1.
7.8.3 Procedure
Except that the apparatus is kept in an environment with a temperature of (37 ± 1) °C, the rest is the same as that specified in 7.6.2. Measure the time from the start of blending to the temperature reaching the maximum value (see Figure 5). The horizontal coordinate corresponding to the intersection of the horizontal coordinate extension line parallel to the highest point of the curve and the extension line of the temperature rising straight line is recorded as the curing time T. The above test is tested 5 times in total.
7.8.4 Determination of test results
7.8.4.1 Class I materials
The test results shall be determined as follows:
a) If at least 4 of the 5 samples have a filling and repair material that does not exceed 5 minutes and a cementing material that does not exceed 10 minutes, the material is considered to meet the requirements of 5.2.5.
b) If 3 or more of the 5 samples have a filling and repair material that exceeds 5 minutes and a cementing material that exceeds 10 minutes, the material is considered to not meet the requirements of 5.2.5.
c) If only 3 of the 5 samples have a filling and repair material that does not exceed 5 minutes and a cementing material that does not exceed 10 minutes, the test shall be retested. In the results of the second test, if 1 or more of the filling and repair materials have a filling and repair material that exceeds 5 minutes and a cementing material that exceeds 10 minutes, the material is considered to not meet the requirements of 5.2.5. 7.8.4.2 Class III materials
Test results are determined as follows:
a) If at least 4 of the 5 samples are equal to or less than 10 minutes, the material is considered to meet the requirements of 5.2.6. b) If 3 or more of the 5 samples exceed 10 minutes, the material is considered not to meet the requirements of 5.2.6. c) If only 3 of the 5 samples are equal to or less than 10 minutes, the test should be repeated. In the second test result, if 1 or more than 10 minutes exceed 10 minutes, the material is considered not to meet the requirements of 5.2.6. 8
1 Time to start blending.
YY1042-2003
Note: From the maximum value of the curve, the intersection of the reverse extension line parallel to the horizontal axis and the extension line of the temperature straight rising part is obtained to obtain the curing time T. Figure 5 Determination of curing time (7.8.3)
7.9 Sensitivity of Class II materials to ambient light
7.9.1 Apparatus
7.9.1.1 Xenon lamp or equivalent light source (e.g. dental lamp) equipped with color conversion filter and UV filter (in accordance with ISO7491).
The color conversion filter is made of tempered (hardened) glass with a thickness of 3 mm, and its transmittance is shown in Figure 6. The relative error between its internal transmittance and the curve shown in Figure 6 should be within ±10%. The UV filter is made of borosilicate glass, and its transmittance for light waves below 300 nm should be less than 1%, and its transmittance for light waves above 370 nm should be greater than 90%. The purpose of using filters is to change the spectrum of xenon lamps to make it equivalent to the spectrum of dental lamps. The filters and light sources should be checked regularly to ensure that the color temperature is maintained between 3600K and 6500K. 7.9.1.2 2 slides
7.9.1.3 Illuminance test instrument, such as an illuminance meter capable of testing (8000±1000)1x. 7.9.1.4 Adjustable workbench
7.9.1.5 Non-reflective black cover to cover the illuminometer. Note: To prevent the reflected light from the illuminometer from interfering with the observation of the sample. 7.9.1.6 Timer with an accuracy of 1 s.
7.9.2 Procedure
In a dark room, place the illuminometer (7.9.1.3) under a xenon lamp. The xenon lamp is equipped with a color conversion filter and an ultraviolet filter (7.9.1.1. The height of the xenon lamp hanging above the workbench can ensure that the illumination of the xenon lamp above is (8000 ± 1000) Ix. [The adjustable workbench (7.9.1.4) should meet the requirements. Cover the illuminometer with a non-reflective black cover (7.9.1.5). Place a mass of material of about 30 mg on a slide (7.9.1.2), then move it to the illuminometer and irradiate it with light for (60 ± 5) s. Remove the slide with the sample from the irradiation area and immediately squeeze the material with a second slide to form a thin layer.
Observe the material with the naked eye to see if it is physically uniform. Note: During the test, if the material begins to solidify, cracks and pores will appear in the thin layer. Comparing the sample with the unirradiated sample will help observation.
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.