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YY/T 0127.7-2017 English PDF (YYT0127.7-2017)

YY/T 0127.7-2017 English PDF (YYT0127.7-2017)

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YY/T 0127.7-2017: Biological evaluation of dental materials -- Part 2: Biological evaluation test method of dental materials -- Pulp and dentine usage test
This part of YY/T 0127 specifies methods of dental materials, pulp and dentine usage test. This part shall be applied to evaluate biocompatibility of dental materials, dentine and endodontic pulp, including evaluation methods and steps that are indispensable to the anticipated clinical application of the materials.
YY/T 0127.7-2017
YY
PHARMACEUTICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 11.060.10
C 33
Replacing YY/T 0127.7-2001
Biological Evaluation of Medical Devices Used in Dentistry -
Part 7. Pulp and Dentine Usage Test
(ISO 7405.2008, Dentistry - Evaluation of Biocompatibility of Medical Devices Used in Dentistry, NEQ)
ISSUED ON. MARCH 28, 2017
IMPLEMENTED ON. APRIL 1, 2018
Issued by. China Food and Drug Administration
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative References ... 6
3 Negative Control Material ... 6
4 Positive Control ... 6
5 Animal and Animal Welfare ... 7
6 Experimental Cycle ... 7
7 Experimental Steps ... 7
8 Result Evaluation ... 12
9 Experiment Report ... 12
Foreword
This Standard is drafted in accordance with stipulations in GB/T 1.1-2009. YY/T 0127 series standard is specific biological test methods and standards of medical devices used in dentistry. It shall be divided into the following sections. -- YY/T 0127.1 Biotic Experiment Method for Dental Materials - Hemolysis Test -- YY/T 0127.2 Biological Evaluation of Medical Devices Used in Dentistry - Part 2. Test Method - Acute Systemic Toxicity. Intravenous Path
-- YY/T 0127.3 Biological Evaluation of Medical Devices Used in Dentistry - Part 3. Endodontic Usage Test
-- YY/T 0127.4 Biological Evaluation of Medical Devices Used in Dentistry - Unit 2. Biological Evaluation Method of Dental Materials - Bone Implant Test
-- YY/T 0127.5 Biological Evaluation of Medical Devices Used in Dentistry - Part 5. Inhalation Toxicity Test
-- YY/T 0127.6 Biological Evaluation of Dental Materials - Unit 2. Biological Test Methods of Dental Materials - Dominant Lethal Test
-- YY/T 0127.7 Biological Evaluation of Medical Devices Used in Dentistry - Part 7. Pulp and Dentine Usage Test
-- YY/T 0127.8 Biological Evaluation of Dental Materials - Part 2. Biological Evaluation Test Method of Dental Materials - Subcutaneous Implant Test
-- YY/T 0127.9 Biological Evaluation of Dental Materials - Part 2. Biological Evaluation Test Method of Dental Materials - Cytotoxicity Tests. Agar Diffusion Test and Filter Diffusion Test
-- YY/T 0127.10 Biological Evaluation of Medical Devices Used in Dentistry - Part 2. Test Method - Salmonella Typhimurium Reserve Mutation Assay (Ames
Mutagenicity Test)
-- YY/T 0127.11 Biological Evaluation of Medical Devices Used in Dentistry - Part 11. Pulp Capping Test
-- YY/T 0127.12 Dentistry - Biological Evaluation of Medical Devices Used in Dentistry - Part 2. Test Method - Micronucleus Test
-- YY/T 0127.13 Biological Evaluation of Medical Devices Used in Dentistry - Part 2. Test Method - Oral Mucous Membrane Irritation Test
Biological Evaluation of Medical Devices Used in Dentistry -
Part 7. Pulp and Dentine Usage Test
1 Scope
This part of YY/T 0127 specifies methods of dental materials, pulp and dentine usage test.
This part shall be applied to evaluate biocompatibility of dental materials, dentine and endodontic pulp, including evaluation methods and steps that are indispensable to the anticipated clinical application of the materials.
2 Normative References
The following documents are indispensable to the application of this Standard. In terms of references with a specified date, only versions with a specified date are applicable to this Standard. The latest version (including all the modifications) of references without a specified date is also applicable to this Standard.
GB/T 16886.2 Biological Evaluation of Medical Devices - Part 2. Animal Welfare Requirements (GB/T 16886.2-2011, ISO 10993-2.2006, IDT)
3 Negative Control Material
Zinc oxide eugenol cement that can be instantly solidified is a suitable negative control material. In terms of long-term research, zinc oxide eugenol cement shall be preferably protected to prevent from hydrolysis. A thin layer of zinc polycarboxylate cement or traditional (self-condensed) glass ionomer cement can be smeared onto the surface of zinc oxide eugenol cement to prevent from hydrolysis. Then, resin-based composite material that adopts acid etching for retention shall be utilized as the filling. It needs to be noted that if zinc oxide eugenol cement directly contacts with resin-based composite material, the polymerization of resin-based composite material will be prevented. Traditional glass ionomer cement can also be considered as a negative control material.
4 Positive Control
When fillings or techniques that are applied to unexposed endodontic pulp can trigger moderate and severe reaction of the endodontic pulp, these are suitable positive control cases (for example, silicone cement).
that contain experimental materials and 4 teeth that contain negative control materials in each experimental cycle. Anesthetize animals and conduct the experiment in accordance with what’s described in 7.2.
7.2 Tooth Preparation
7.2.1 Cavity preparation
Remove all tooth stones and soft mucinous deposits on the surface of teeth. Take 3% (volume fraction) hydrogen peroxide to clean and sterilize the surface of teeth, then, use disinfectant that contains iodine or chlorhexidine to sterilize the teeth. Under sufficient vapor spray, take sharp drill to prepare a necessary number of V-type cavities on the buccal side of the teeth or the lip side. The thickness of residual dentine on the bottom of all the cavities shall be < 1 mm, and preferably < 0.5 mm. However, the endodontic pulp shall not be exposed. Experimental filling materials require a different operation. Other than this, all cavities shall be rinsed with water, and dried with absorbent cotton.
Note 1. if animals manifest apparent gingival inflammation, remove all tooth stones and soft mucinous deposits on the surface of teeth several days
before cavity preparation; repeat the step of cleaning if necessary, till the inflammation is under control.
Note 2. during cavity preparation, impedance measuring instrument that has been calibrated can be adopted, for example, apical instrument, to assist in the estimation of the thickness of the residual dentine.
7.2.2 Material preparation
Prepare experimental materials in accordance with product specification. If product specification requires the application of cavity lining material or treatment agent (for example, dentine glue), these operations can be added in accordance with the manufacturer’s instruction.
7.2.3 Cavity filling
In accordance with the principle of random allocation, experimental materials shall be utilized to fill at least 7 cavities, negative control materials shall be utilized to fill at least 4 cavities in each experimental cycle. If necessary (refer to the note below), there shall be 4 positive control cavities in each experimental cycle.
Note. if laboratory possesses previous positive control database, it is unnecessary to conduct another positive control experiment, unless positive reaction needs to be verified.
7.2.4 Postoperative observation and nursing
Slight inflammation. the structure of dental pulp tissue that passes
dentinal tubule and adjoins cavity bottom is normal, inflammatory
cells are dispersed
Moderate inflammation. the structure of dental pulp tissue that
passes dentinal tubule and adjoins cavity bottom is still normal,
small-scale lesions of concentrated inflammatory cells exist
Severe inflammation. the structure of dental pulp tissue that
passes dentinal tubule and adjoins cavity bottom is abnormal,
inflammatory cells infiltrate extensively
Abscess is formed, or extensive inflammatory cells infiltrate to
tissue area except from dental pulp tissue that adjoins dentinal
tubule on cavity bottom
During the evaluation of each section, record the minimum thickness of residual dentine, including the measurement of the distance from cavity bottom to endodontic pulp - (early stage) dentine interface and the distance along dentinal tubule from the vertical angle. The latter refers to when the plane section is not completely consistent with dentinal tubule, namely, each dentinal tubule in this area fails to stretch from cavity bottom to pulp - (early stage) dentine interface, then, the basic direction of dental tubule shall be complied with during the measurement. Calculate inflammatory response index in each experimental cycle, namely, add the grading score of each section together, then, divide it by the total number of sections being observed. In experimental data, experimental materials (including lining materials and treatment agents recommended by manufacturers), and results of negative control and positive control shall be listed out respectively. Cavity that’s filled with positive control materials can adopt previous data that’s acquired under the same experimental conditions. In addition, record the number of cavity bottoms or side walls with bacteria in experimental materials and control materials in each experimental cycle. In accordance with the above-mentioned grading standard, measurable maximum thickness range of residual dentine and observed bacterial microleakage amount, determine inflammatory response index of experimental materials in each experimental cycle.
7.5 Odontoblast Survival Analysis (optional)
In terms of odontoblast survival analysis in tissue formation, select at least 5 sections that are distributed in equal intervals along cavity bottom. Conduct H-E staining, select distinguishable cells with visibility of the whole pulp on cavity bottom - (early stage) dentine interface, then, observe under amplified times. Use cell counter to calculate the number of odontoblasts with integral formation that’s contained within the unit length of the whole pulp on cavity bottom - (early stage) dentine interface. This interface refers to the position that links up cavity bottom through dentinal tubule, as it is shown in Figure 1.
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