GB/T 42761-2023 English PDF (GBT42761-2023)

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GB/T 42761-2023: Screening method for erosion potential of oral rinses on dental hard tissues
GB/T 42761-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.40
CCS Y 43
Screening Method for Erosion Potential of Oral Rinses on
Dental Hard Tissues
(ISO 28888:2013, Dentistry - Screening Method for Erosion Potential of Oral Rinses
on Dental Hard Tissues, MOD)
ISSUED ON: MAY 23, 2023
IMPLEMENTED ON: DECEMBER 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Requirements ... 4
5 Reagents and Materials ... 5
6 Instruments and Equipment ... 5
7 Analytical Procedures ... 6
8 Evaluation Report ... 8
Appendix A (informative) Comparison of Structure No. between this Document and
ISO 28888:2013 ... 9
Appendix B (informative) Technical Differences between this Document and ISO
28888:2013 and Causes for the Differences ... 10
Bibliography ... 11
Screening Method for Erosion Potential of Oral Rinses on
Dental Hard Tissues
1 Scope
This document describes a method for evaluating the erosion potential of oral rinses on dental
hard tissues using enamel and (or) dentine acid-etching models.
This document is applicable to the evaluation of erosion potential of oral rinses on dental hard
tissues.
This document does not apply to the evaluation of oral rinses containing fluoride.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods (GB/T 6682-
2008, ISO 3696:1987, MOD)
GB/T 9937-2020 Dentistry - Vocabulary (ISO 1942:2009, MOD)
3 Terms and Definitions
What is defined in GB/T 9937-2020, and the following terms and definitions are applicable to
this document.
3.1 tooth erosion; dental erosion
Tooth erosion / dental erosion refers to the progressive loss of calcified dental tissue by
chemical processes that do not involve bacterial action.
[source: GB/T 9937-2020, 2.292]
4 Requirements
4.1 Overview
This document is a risk assessment of enamel and dentine acid-etching caused by oral rinses
and a preliminary screening of the erosion potential of all fluoride-free oral rinses. If the product
fails the screening, adopt a more complex and clinically relevant test method specified in the
product standard for the testing.
4.2 Maximum pH Drop Value
The maximum pH drop value allowed in this document is 1.0.
If the pH drop value is greater than 1.0, then, the oral rinse fails the screening test. Under this
circumstance, a more complex and clinically relevant test method should be selected, so as to
determine the erosion effect of the oral rinse.
5 Reagents and Materials
5.1 Calcium chloride dihydrate (CaCl2  2H2O), analytically pure.
5.2 Citric acid (C6H8O7), analytically pure.
5.3 Potassium hydroxide (KOH), analytically pure.
5.4 Hydrochloric acid (HCl), analytically pure.
5.5 Trisodium citrate dihydrate (C6H5Na3O7  2H2O), analytically pure.
5.6 Potassium dihydrogen phosphate (KH2PO4), analytically pure.
5.7 Distilled water (H2O), Grade-2 water in compliance with GB/T 6682.
5.8 For citric acid control buffer solution, in accordance with 7.2.3, prepare the following three
standard citric acid buffer solutions:
---Solution 1: 1.0% citric acid solution, pH is 3.60 at 25 C;
---Solution 2: 0.25% citric acid solution, pH is 3.68 at 25 C;
---Solution 3: 0.07% citric acid solution, pH is 3.77 at 25 C.
6 Instruments and Equipment
6.1 Beaker, 50 mL, made of borosilicate glass.
6.2 Beaker, 100 mL, made of borosilicate glass.
6.3 Pipette, with a measuring range of 0.01 mL ~ 1 mL.
6.4 Volumetric flask, 100 mL, 1 L.
6.5 Analytical balance, with an accuracy of 0.0001 g or higher.
6.6 Magnetic stirrer, equipped with a stirring magneton coated with polytetrafluoroethylene
(PTFE).
6.7 Thermometer, with an accuracy of 0.1 C or higher.
6.8 pH meter (pH electrode), calibrated, with an accuracy unit of  0.05 pH.
Use standard buffer solutions with pH of 2.0, 4.0 and 6.0 at 25 C, or standard buffer solutions
with pH of 1.68, 4.01 and 6.86, or pH buffer solutions prepared in accordance with national
standards for the calibration. In addition, check the linear response, and the slope per pH unit
shall be at least 58 mV.
NOTE: commercially available pH standard buffer solutions that comply with national standards
and with attached certificates can be used.
7 Analytical Procedures
7.1 Sample Selection
From three different batches of oral rinses, take two representative samples from each batch
(six samples in total).
7.2 Preparation of Solutions
7.2.1 Preparation of stock solutions
---Stock solution A (1 mol/L CaCl2): add 147.01 g of CaCl2  2H2O (5.1) to 1 L of water
(5.7);
---Stock solution B (1 mol/L KH2PO4): add 136.09 g of KH2PO4 (5.6) to 1 L of water (5.7).
NOTE: the two stock solutions need to be prepared immediately before use.
7.2.2 Preparation of screening solution
In accordance with the following steps, prepare the screening (calcium phosphate) solution:
a) Add 500 mL of water (5.7), 1.266 mL of stock solution A (7.2.1) and 0.760 mL of
stock solution B (7.2.1) to the 1 L volumetric flask;
b) Use hydrochloric acid (5.4) to adjust pH to 5.05  0.05;
NOTE 1: when pH is lower than 5.05  0.05, potassium hydroxide (5.3) can be used to adjust the
pH.
c) Use water (5.7) to dilute to 1 L.
7.3.3 Test duration
Stop after pH becomes stable.
7.3.4 Number of tests
For each test sample (six samples in total), repeat the test for four times.
7.3.5 Data recording and processing
For each test, record the pH of the test sample [i.e., the control buffer solution (5.8) or oral
rinse], the initial pH of the screening (calcium phosphate) solution (7.2), the pH after adding
the test sample, and the pH drop value (the initial pH minus the final pH).
Record the original data of each type of test material.
7.3.6 Result evaluation
Respectively calculate the average value of the pH drop values of four repeated tests for each
sample (six samples in total) and the standard deviation of the pH drop value of the test sample.
If the average pH drop value of each sample is equal to or less than 1.0, then, it passes the test.
8 Evaluation Report
In accordance with the test process, issue an evaluation report, which includes the following
information:
a) Complete identification of the oral rinse under test, including product name,
manufacturer, batch No. and type of administration (such as: canned, pasty and
syringe form);
b) Storage conditions of oral rinse;
c) Number of test samples;
d) Whether the test result is PASS;
e) Standard deviation of the tests described in this document (if applicable);
f) Reference standard;
g) Test date;
h) Test personnel’s signature and date.