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YY 0271.2-2016
Dentistry - Water-based cements - Part 2. Resin-modified cements
ICS 11.060.10
C33
People's Republic of China Pharmaceutical Industry Standard
YY 0271.2-2016/ISO 9917-2.2010
Replacing YY 0271.2-2009
Dentistry water-based cement
Part 2. Resin modified cement
Part 2. Resin-modifiedcements
(ISO 9917-2.2010, IDT)
Released on.2016-07-29
2018-06-01 implementation
State Food and Drug Administration issued
Content
Foreword III
Introduction V
1 range 1
2 Normative references 1
3 Terms and Definitions 1
4 Classification and application 2
4.1 Classification 2
4.2 Application 2
5 Requirements 2
5.1 Material 2
5.2 Working hours 2
5.3 Curing time - only for Class 1 and Class 3 cement 2
5.4 Film thickness - only for cemented cement (see 4.2) 2
5.5 Flexural strength 2
5.6 X-ray resistance 2
5.7 Color and color stability - only for repairing cement 3
6 sampling 3
7 Test conditions and sample preparation 3
7.1 Test conditions 3
7.2 Harmonic method 3
7.3 Appearance requirements 3
8 Packaging, labeling and information provided by the manufacturer 4
8.1 Packing 4
8.2 Identification and instruction manual 4
Appendix A (Normative) Test of working time and curing time 6
Appendix B (Normative) Film thickness test - only for cemented cement 8
Appendix C (Normative) Test for Flexural Strength 10
Appendix D (Normative) X-ray resistance test 14
Appendix E (Normative) Test for color and color stability - only for repair and cementing 17
Reference 18
YY 0271.2-2016/ISO 9917-2.2010
Foreword
The full technical content of this standard is mandatory.
YY 0271 "Dental Science Water-based Cement" is divided into two parts.
--- Part 1. Powder/liquid acid and alkali cement;
--- Part 2. Resin modified cement.
This part is the second part of YY 0271.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This section replaces YY 0271.2-2009 "Dental Water-Based Cement Part 2. Photocuring Cement".
Compared with YY 0271.2-2009, the main changes in this section are as follows.
---The standard name was changed from "Dental Water-Based Cement Part 2. Light-Cured Cement" to "Dental Science Water-Based Cement" No. 2
Part. Resin modified cements;
--- Added standard introduction;
--- Changed Chapter 1 "Scope";
--- Changed Chapter 2 "Regulatory References";
--- Added the terminology of the term "terms and definitions" in Chapter 3, changed the definition of "cure time", and deleted the "initial hardening time"
definition;
--- Changed Chapter 4 "Classification";
--- Increased the requirements and test methods for 5.2 "working hours";
--- Added 5.4 "film thickness" requirements and test methods;
--- Added Table 1 "Dental Cement Requirements";
--- Added Table 2 "Requirements for Identification and Instruction Manual";
--- Appendix C added the test of flexural strength Figure C.2, exemplifying another mold for preparing flexural strength specimens;
--- Appendix digital DX radiation resistance test has been added to the digital device method;
--- Removed the "initial hardening time" requirements and test methods;
--- Removed the "cure depth" requirements and test methods;
--- Removed the requirements and test methods for "opacity".
This section is equivalent to ISO 9917-2.2010 "dental science water-based cement part 2. resin modified cement".
The documents of our country that have a consistent correspondence with the international documents referenced in this part are as follows.
---GB/T 6682-2008 Analytical laboratory water specifications and test methods (ISO 3696.1987, MOD);
---GB/T 7408-2005 Data element and exchange format information exchange date and time representation (ISO 8601.2000,
IDT);
---GB/T 9937 (all parts) Oral vocabulary (all parts) (ISO 1942, IDT);
---YY/T 0631-2008 Determination of colour stability of dental materials (ISO 7491.2000, IDT).
Please note that some of the contents of this document may involve patents. The issuing organization of this document is not responsible for identifying these patents.
This part is proposed by the State Food and Drug Administration.
This part is under the jurisdiction of the National Technical Committee for Standardization of Dental Materials and Devices (SAC/TC99).
This section drafted by. State Food and Drug Administration Peking University Medical Device Quality Supervision and Inspection Center, Minnesota Mining Manufacturing
YY 0271.2-2016/ISO 9917-2.2010
(Shanghai) International Trade Co., Ltd., Rijin Dental Materials (Kunshan) Co., Ltd.
The main drafters of this section. Li Yuan, Yuan Shenpo, Zhang Xiaohui, Xu Zhengguo, Zhang Dianyun, Min Min, Shen Xizhen, Lin Hong, Zheng Gang.
The previous versions of the standards replaced by this section are.
---YY 0271.2-2009.
YY 0271.2-2016/ISO 9917-2.2010
introduction
This part of YY 0271 specifies the requirements and test methods for resin modified cements. The curing of these cements is caused by acid-base reaction
It is completed together with the polymerization reaction. The polymer-based component of the reaction can be activated by mixing different components or by external energy.
The test method used in this part of the YY 0271 standard should be as close as possible to ISO 4049 (YY 1042-2011/ISO 4049.2009, MOD)
Consistent with the ISO 9917-1 (YY 0271.1-2016/ISO 9917-1, IDT) standard.
This section of YY 0271 does not contain qualitative and quantitative requirements for product biological hazards, but is recommended for assessing possible biological risks.
When it is harmful, please refer to GB/T 16886.1 "Biological evaluation of medical devices Part 1. Evaluation and testing in the process of risk management" and
YY/T 0268 "Evaluation and Test of Unit 1 of Biological Evaluation of Dental Medical Devices for Dentistry".
YY 0271.2-2016/ISO 9917-2.2010
Dentistry water-based cement
Part 2. Resin modified cement
1 Scope
This part of YY 0271 specifies the requirements and test methods for dental resin modified cements for cementing, underlaying or lining and repair.
law. These cements are water-based materials that cure by multiple reactions including acid-base reactions and polymerization reactions.
For example, traditional polyalkate glass ionomer cements are usually made up of ion-dissolving aluminosilicate glass and polyalkenoic acid in water.
The reaction is generated in the environment. The cements referred to in this part of YY 0271 are usually capable of curing by this water-based acid-base reaction, but in addition
It can also be cured by polymerization.
Note. Manufacturers and inspection agencies should pay close attention to the closely related international standards ISO 4049 (YY 1042-2011/ISO 4049.2009, MOD) and ISO 9917-1
(YY 0271.1-2016/ISO 9917-1, IDT). The most appropriate international standards mentioned above should be considered when evaluating any particular product.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
ISO 1942 (all parts) Oral vocabulary (Dentistry-Vocabulary)
ISO 3665.1996 Technical specification for dental radiographic film in photography (Photography-Intra-oraldentalra-
diographicfilm-Specification)
ISO 3696 Analytical Laboratory Water Specifications and Test Methods (Waterforanalyticallaboratoryuse-Specification)
Andtestmethods)
ISO 7491 Determination of the color stability of dental materials (Dentalmaterials-Determination ofcolourstability)
ISO 8601 data element and exchange format information exchange date and time representation (Dataelementsandinterchange
formats-Informationinterchange-Representationofdatesandtimes)
3 Terms and definitions
The following terms and definitions defined by ISO 1942 apply to this document.
3.1
Reconciliation time mixingtime
The components are brought to this part of the working time required for thorough mixing.
Note. Cements included in the scope of this section of YY 0271 include single component cements that need to be blended and do not require blending.
3.2
Working time workingtime
A period of time from the time of reconciliation (if needed), during which the cement material can be manipulated without adversely affecting its performance
influences.
Note. For Class 3 cements that require photoactivation (see 4), their working time is determined without photoactivation.
3.3
Curing time settingtime
The time from the start of the blending to the completion of the cure. The curing is accomplished by the ability of the cement to withstand a fixed load head.
YY 0271.2-2016/ISO 9917-2.2010
3.4
Outer package outerpack
A package in which several single dose containers or capsules are packed together.
3.5
Outermost packaging
A package in which the cement and accessories are packed together, the accessories include instructions for use and any gages supplied with the cement or
Reconciliation equipment.
4 Classification and application
4.1 Classification
In this section, the cements are classified according to their curing characteristics as follows.
-- Class-1. The curing reaction of the polymerizable component in the cement is activated by a chemical reaction after mixing the components.
-- Class-2. The curing reaction of the polymerizable component in the cement is activated by light.
--Class-3. The curing reaction of the polymerizable component in the cement is activated by the chemical reaction after mixing the components, and also by light.
activation.
4.2 Application
In this section, cement has the following applications in the clinic.
a) cementing;
b) a bottom or lining;
c) Repair.
5 requirements
5.1 Materials
During the test, each component should have no visible foreign matter, and the liquid agent provided separately should not have gelation.
5.2 Working hours
According to the test in Appendix A, the working time should meet the requirements of Table 1, and not less than the value given by the manufacturer (see Table 2, item 24).
5.3 Curing time - only for Class 1 and Class 3 cements
According to Appendix A, the curing time of Class 1 and Class 3 cements should meet the requirements of Table 1 and not greater than the value given by the manufacturer (see
Table 2, item 25).
5.4 Film thickness - only for cemented cements (see 4.2)
According to Appendix B, the film thickness of the cemented cement should meet the requirements of Table 1.
5.5 Flexural strength
According to the test in Appendix C, the flexural strength should meet the requirements of Table 1.
5.6 X-ray resistance
5.6.1 If the manufacturer claims that the cement has X-ray resistance (see Table 2, item 16), it shall be tested according to Appendix D, and its X-ray resistance shall be equal.
YY 0271.2-2016/ISO 9917-2.2010
An aluminum plate at or above the same thickness as the material.
5.6.2 If it is claimed that the cement has strong X-ray resistance, it should not be lower than the manufacturer's claimed value (see Table 2, item 17).
0.5mm.
5.7 Color and color stability - only for repairing cement
According to the test in Appendix E, the color of the cement after curing should be consistent with the color plate provided by the manufacturer.
When tested according to Appendix E and ISO 7491, the color after 7d can only change slightly.
Table 1 Requirements for dental cement
application
membrane thickness
Mm
maximum
operating hours
Min
Minimum
Curing time a
Min
maximum
Flexural strength
MPa
Minimum
Sticking 25 1.5 8 10
Bottom or lining - 1.5 6 10
Repair - 1.5 6 25
a Only for Class 1 and Class 3 cements. The testing of the three types of cement was carried out without photoactivation.
6 sampling
The same batch of samples is taken from the retail packaging and the amount of sample should be sufficient to complete all tests and the necessary repeat tests.
7 Test conditions and sample preparation
7.1 Test conditions
The environment for all sample preparation and testing should be maintained at a temperature of (23 ± 2) ° C and the relative humidity is always controlled at (50 ± 20)%. If water
The temper was stored refrigerated and the cement was brought to a temperature of (23 ± 2) °C before the test. The test equipment shall be maintained in the environment specified by each test.
For Class 2 and Class 3 cements, working time testing was performed without photoactivation.
All test waters used in this section should use Class 2 water not less than ISO 3696.
For Class 2 and Class 3 cements, reference should be made to the external energy source specified in the manufacturer's instructions (see Table 2, item 26).
The energy source is in an operating state that satisfies the experimental conditions.
7.2 Harmonic method
The cement should be prepared in accordance with the manufacturer's instructions. A sufficient amount of cement is reconciled to ensure that each sample is taken from the same blend. One
Only one sample can be prepared for the sub-harmonic.
Note. Capsule type cement, some samples need to reconcile multiple capsules at the same time. Similarly, the cement provided in a single dose package may require more than one sample per sample.
Packing.
7.3 Appearance requirements
Visual inspection should be performed to see compliance with the requirements of 5.1 and 8.
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8 Packaging, labeling and information provided by the manufacturer
8.1 Packaging
The components of the cement should be packaged in a suitable sealed container that provides adequate protection to the cement and does not provide quality
Can have adverse effects.
Multiple containers can also be used in one package to make them a single package.
Note. Single paste and powder capsule products can be sold as a package containing multiple unit doses of cement.
8.2 Identification and instruction manual
Where applicable, the information listed in Table 2 should be clearly identified on the outermost packaging or container (multi-dose packaging or capsules).
Each package of cement should be accompanied by instructions. The instructions should include the information given in Table 2 for the applicable cement (Chapter 4).
In addition to the information specified in Table 2, the manufacturer may provide additional information.
Note. Some of the information in Table 2 is mandatory and some are optional. The symbol "-" indicates that this item is not applicable or optional for this product. Table 2
Contains selectable references as a guide for the manufacturer and information that may be useful to the dentist.
Table 2 Requirements for identification and instruction manual
Serial number requirement
Outer packaging
(see 3.5)
Capsule type
Outer packaging
(see 3.4)
Capsule type (single dose
Volume), syringe
Packed or bottled
Production plant
Instruction manual
insert
1 Product Name MM -a Mb
2 Manufacturer's logo or name MM - M
3 Address of the manufacturer or agent responsible for sales M - - M
4 URL - - - -
5 Regional/national legal requirements information MM - M
6 Recommended storage conditions M - - M
7 batch number given by the manufacturer MM - -
When the cement is stored under the conditions recommended by the manufacturer, in accordance with ISO 8601
Required expiration date
MM - -
9 Shelf life under the storage conditions recommended by the manufacturer - - - -
10 Classification of cements (see 4.1) M - - -
11 Clinical applications (see 4.2) - - - M
12 Capsules or Sleeve Types of Containers/Capsules MM - -
13 net weight per container/capsule - M - M
The color and/or color of the cement according to the colorimetric plate specified by the manufacturer (only
Suitable for multi-color cements)
- M Mc -
15 The cement that claims to be occluded should clearly indicate its effect d M - - M
A cement that claims to have X-ray resistance (see 5.6) should be clearly indicated
Its effect
- - - M
YY 0271.2-2016/ISO 9917-2.2010
Table 2 (continued)
Serial number requirement
Outer packaging
(see 3.5)
Capsule type
Outer packaging
(see 3.4)
Capsule type (single dose
Volume), syringe
Packed or bottled
Production plant
Instruction manual
insert
If the X-ray resistance of the cement is specifically stated, it should be marked 1mm.
Equivalent aluminum plate thickness of thick cement
- - - M
Recommended ratios of components (eg, powder to liquid ratio) and weighing instruments (eg. scale
Usage instructions for measuring spoons, etc.) and mass ratios accurate to 0.1g (applicable only to
Hand-modulated cement
- - - M
19 Speed of powder added to the liquid (only for hand-adjustable cement) - - - M
20 If reconciliation is required, reconcile time (see 3.1) - - - M
Harmonic conditions (if applicable, blending plates, conditions and types of knives), only applicable
Hand-regulated cement
- - - M
22 If necessary, physically contact the components of the capsule cement - - - M
23 Method, time and type of mechanical blending if needed - - - M
24 working hours (see 3.2) - - - M
25 Curing time (only for Class 1 and Class 3 cements, see 3.3) - - - M
Recommended external energy source, lighting time and any special instructions for the device
(only for Class 2 and Class 3 cements)
- - - M
The maximum thickness of the polymer layer [only for clinical application in 4.2 b) and
c) Class 2 and Class 3 Cement]
- - - M
Recommended minimum time to start grinding and polishing (only for repairing water gates)
Ting, see 4.2)
- - - M
29 Recommended Grinding Methods (only for repairing cements, see 4.2) - - - M
30 If applicable, need to be glazed - - - M
31 Measures to avoid premature curing (only for Class 2 and Class 3 cements) - - - M
a “-” indicates that this item is not applicable to the container/logo/instruction or that this requirement is not feasible or possible or that the information is informative.
b “M” indicates that this item is mandatory.
c For single-dose/small-dose containers, separate containers should be identified for color/color, either directly or through the instruction manual insert.
A reference or guide.
d A opaque cement can be included in the color.
YY 0271.2-2016/ISO 9917-2.2010
Appendix A
(normative appendix)
Working time and curing time test
A.1 Appliances
A.1.1 Test environment, able to maintain temperature (37 ± 1) ° C and relative humidity of not less than 50%.
A.1.2 Indenter, flat end face with a certain mass and a certain diameter. The tip of the indenter should be cylindrical and approximately 5 mm in length. End of indenter
It should be flat and perpendicular to the long axis of the needle.
A.1.2.1 Indenter during working time, mass (28.00 ± 0.25) g, diameter (2.0 ± 0.1) mm.
A.1.2.2 Indenter for curing time, mass (400 ± 5) g, diameter (1.0 ± 0.1) mm.
A.1.3 Metal mold, thickness (5 ± 2) mm, with a diameter of (10 ± 2) mm or a side length (10 ± 2) mm square hole, at least the area
16cm2 piece of metal.
Note. The inner corner of the square hole should be rounded.
A.1.4 Metal block, thickness of at least 8mm, volume of at least 60cm3.
A.1.5 Aluminum foil.
A.1.6 Timer with 1s accuracy.
A.2 Test of working hours
A.2.1 Steps
Class 2 and Class 3 cements should be operated without light at wavelengths from 400 nm to 500 nm, such as in darkrooms and/or filtered strips.
Under the pieces.
The test shall be carried out under the conditions described in 7.1.
Place the mold set to (23 ± 1) °C (A.1.3) on the metal block of the covered aluminum foil (A.1.5) also set to (23 ± 1) °C.
(A.1.4), then fill the mold into a flat surface.
Carefully press the indenter 10 hours before the end of the working hours claimed by the manufacturer (see Table 2, item 24) or the minimum value given in Table 1 (take the large value)
(A.1.2.1) Vertically reduce to the surface of the cement for 5 s. Note that the indenter forms a complete circular indentation on the surface of the cement.
The test was repeated with two separately adjusted cements.
A.2.2 Result determination
A complete round indentation is formed on the surface of the cement, which meets the requirements. All three indentations should be at the manufacturer’s stated working hours (see
Tables 2 and 24) and Table 1 are formed before the minimum working time of 10 s.
A.3 Test of curing time - only for Class 1 and Class 3 cements
Note. The purpose of the test is to confirm that Class 1 and Class 3 cements can also be cured without photoactivation.
A.3.1 Procedure
Place the mold (A.1.3) with the set temperature to (23 ± 1) °C on the aluminum foil (A.1.5), and adjust the timing from the adjustment or extrusion of the cement.
Fill the mold into a flat surface with a good cement.
YY 0271.2-2016/ISO 9917-2.2010
60 s after the end of the blending, the components of the mold, aluminum foil and cement sample were placed on the metal block (A.1.4) and placed in the test environment (A.1.1).
in. Make sure that the mold, aluminum foil and metal block are in intimate contact.
Class 3 cements should be tested without photoactivation.
The curing time claimed by the manufacturer (see Table 2, item 25) or the limit given in Table 1 (taken small value) is 10s after the end, carefully indenting the head
(A.1.2.2) Vertically reduce to the surface of the cement for 5 s. Lift the indenter from the surface and use a 2x magnifying glass to see if the indenter is in the cement
The surface does not form a complete circular indentation.
Repeat the test twice more.
A.3.2 Result determination
None of the three samples formed a complete circular indentation on the surface of the cement, which met the requirements. The cement that needs to be activated by light activation is fixed
It is a class 2 type of cement.
YY 0271.2-2016/ISO 9917-2.2010
Appendix B
(normative appendix)
Film thickness test - only for cemented cement
B.1 Appliances
B.1.1 Two glass plates with optical flatness, square or round, transparent, contact area (200±25) mm2, each glass plate
It should have a uniform thickness of at least 5 mm.
B.1.2 Loading device, as shown in Figure B.1 or equivalent to the vertical load of (150 ± 2) N on the specimen by the upper glass plate
method.
The indenter attached to the bottom end of the load beam should be horizontal and parallel to the base.
The load should be applied to the specimen in a smooth and non-rotating manner.
Description.
1---sample;
2---glass plate.
Figure B.1 Loading device for film thickness test
B.1.3 Dial gauge or equivalent measuring instrument with a measuring accuracy of 1 μm or more.
YY 0271.2-2016/ISO 9917-2.2010
B.2 steps
Measure and record the thickness of the two optical flat glass sheets (B.1.1) stacked together to the nearest 1 μm, which is denoted as A. Remove on
Glass plate, place (0.10±0.05) mL or equivalent mass of well-balanced cement in the center of the lower glass plate, and then place the lower glass plate
In the center position under the loading device (B.1.2). The second glass plate was placed in the same direction as the initial measurement on the cement.
Applying the vertical direction to the center of the specimen through the upper glass plate 10s before the end of the working time claimed by the manufacturer (see Table 2, item 24)
(150 ± 2) N force. Make sure the cement is completely filled between the two glass plates. After applying the force for at least 10 minutes, the two glass plates are added
The carrier was removed and the thickness of the two sheets of glass and cement film at the same position was measured. This size is denoted as B.
The difference in thickness (BA) between the two glass plates with and without the cement was recorded as the film thickness, and the test was repeated four times.
B.3 Result determination
At least 4 of the 5 test results are not more than 25 μm, and the cement meets the requirements of Table 1. If only 2 or less
If the test result is not more than 25 μm, the cement does not meet the requirements. If the three test results are not more than 25 μm, then 5 more samples should be tested.
The results of the second group of 5 tests are not more than 25μm, and the cement meets the requirements of Table 1.
YY 0271.2-2016/ISO 9917-2.2010
Appendix C
(normative appendix)
Flexural strength test
C.1 Appliances
C.1.1 Mold for sample preparation
The exact type of mold is not required, but samples should be prepared in accordance with the manufacturer's instructions. C.1.1.1 and C.1.1.2 list two
A suitable mold.
C.1.1.1 Mold for preparing samples of (25 ± 2) mm × (2.0 ± 0.1) mm × (2.0 ± 0.1) mm. Figure C.1 shows a suitable
Combined mold. The mold can be made of stainless steel, PMMA [poly(methyl methacrylate)] cast sheet or other suitable ones that do not counteract with the cement
Made of model material. The release agent helps to remove the sample. If a release agent is used, the release agent should not affect the curing of the cement.
Note. For example, a solution of n-hexane containing 3% paraffin is a suitable release agent.
The unit is mm
Figure C.1 Flexural strength specimen mold
C.1.1.2 Mold, another sample preparation mold as shown in Figure C.2. The mold block should be made of PMMA plates that avoid sticking. regular
Check the mold block and replace it when the mold block is damaged or worn. The release agent helps to remove the sample. If a release agent is used, the release agent should not
Affect the curing of cement.
Note. For example, a solution of n-hexane containing 3% paraffin is a suitable release agent.
The mold that applies the horizontal force can be made of any rigid material (aluminum used in Figure C.2). Pressurize the cement through the mold to make the water gate
The styrene is fixed in the mold block while keeping the upper and lower surfaces of the sample in a horizontal assembly.
YY 0271.2-2016/ISO 9917-2.2010
The unit is mm
Note. In addition to the height of the specified block (marked *) included in the mold profile, other dimensions are not strictly required.
Figure C.2 Another mold design and assembly drawing for preparing flexural strength specimens
C.1.2 Flexural strength performance test equipment and fixtures
C.1.2.1 Test equipment, calibrated to provide a constant (0.75 ± 0.25) mm/min crosshead speed or (50 ± 16) N/min plus
Load rate.
C.1.2.2 Test fixture, mainly consisting of two cylinders with a center distance of 20 mm, parallel to each other (2 mm in diameter) and one in the above two cylinders
The middle consists of a third cylinder (2 mm in diameter) parallel to it, and the three cylinders can constitute a three-point loading of the specimen.
C.1.2.3 Transparent glass sheets/plates, each with sufficient area to cover the mold.
C.1.2.4 Polyester film, such as dental molded tablets.
C.1.2.5 Water bath, the temperature can be maintained at (37 ± 1) °C.
C.1.2.6 Micrometer or equivalent, with an accuracy of 0.01 mm or more.
C.1.2.7 Small spiral mold clamp, suitable for fixing the assembled sample mold in the condition of water bath (C.1.2.5).
C.1.2.8 External energy source, recommended by the manufacturer (see Table 2, item 26) for the tested cement.
C.2 Sample preparation
C.2.1 Preparation of Samples - Class-1 Cement
Make sure the mold surface is clean and, if applicable, apply a suitable release agent. Reconcile the cement according to the manufacturer's instructions and immediately press it into the mold.
YY 0271.2-2016/ISO 9917-2.2010
In the center, the cement will flow outward, and the cement will overflow slightly. Do not try to form a plane. The above steps are in the working hours of the cement (see table)
2, 24 items) completed.
In the working hours of the cement (see Table 2, item 24), a piece of polyester film (C.1.2.4) and glass plate (C.1.2.3) are covered.
On the surface of the cement, a horizontal pressure is applied to the above components to extrude excess cement. Clamp the assembly with a small spiral mold clamp (C.1.2.7).
Cured in a water bath (C.1.2.5) for 1 h.
After curing, the sample was taken out of the mold. Grind the sample with P150 or P320 sandpaper to remove any burrs, taking care not to damage
Samples were then stored in water at (37 ± 1) °C (24 ± 1) h until testing.
Five samples were prepared.
C.2.2 Sample preparation - Class-2 and Class 3 cements
In the working hours of the cement (see Table 2, item 24), the cement is filled into the mold, and a polyester film is placed on the upper and lower sides of the mold (C.1.2.4).
And glass plates (C.1.2.3). Align the output window of the external energy source (C.1.2.8) with the center of the sample and against the glass plate, according to the recommended photo
The time is illuminated by the portion of the sample. Move the output window to the side of the center position and overlap the front illuminated area, in accordance with the recommended illumination
Time illumination sample.
Note. The degree of overlap should cover no more than half of the area illuminated by the front output window.
The other side of the center portion of the sample was irradiated in the same manner. Repeat the above process until the full length of the sample is recommended according to the recommended irradiation time.
Irradiation. The above irradiation step was repeated on the other side of the sample. Clamp the assembly with a small spiral mold clamp (C.1.2.7) and place in water at (37 ± 1) °C
Bath (C.1.2.5) for 15 min. The sample is then removed from the mold and one end of the sample is marked to indicate that it is the first cured surface. use
P150 or P320 sandpaper removes all burrs and does not sand the upper and lower surfaces of the specimen. Store the sample in water at (37 ± 1) °C (24 ± 1) h,
Until the test.
Five samples were prepared.
C.3 steps
After storage (24 ± 1) h in water at (37 ± 1) °C, each sample was c...
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