TX Q&A

Dental retraction materials are a type of auxiliary material used in oral treatment, for retracting the gums during tooth preparation, impression taking, or crown adhesion. Products with different main chemical compositions should be divided into different registration units. Products with different characteristics leading to different clinical application techniques should be classified into different registration units, such as retraction cords and retraction pastes should be separate registration units. Products with vasoconstrictor or hemostatic functions and those without should be separate registration units.

In addition to the standard registration application materials, it is recommended to focus on the following research data for non-spherical optical design: 1. Optical design and principles of non-spherical design. 2. A comprehensive description of the production technology to achieve non-spherical design. 3. Verification data proving the non-spherical design of the lens. 4. If a company intends to promote the product's non-spherical design for improved optical imaging in the proposed instructions, corresponding project requirements, test methods, and a testing report should be included in the product's technical requirements.

Select a complete set of tubing with the highest DEHP content, use a suitable extraction solution (such as ethanol-water) and testing methods to simulate the most stringent clinical conditions (e.g., according to the chemical performance test liquid preparation method specified in YY 0267 "Chemical Properties Test of Cardiovascular Implants and Extracorporeal Circulation Blood Circuit of Blood Purification Devices," circulation at 200mL/min flow rate and 37°C for 5.5 hours under the maximum blood flow rate claimed for clinical use), and test the total amount of DEHP leached. Provide an analysis of the toxicity, safety limits, and source documents for human blood contact with DEHP, and evaluate the safety for different weight-appropriate populations based on physiological characteristics.

For evaluation indicators showing statistical differences in the test, the test report should clearly indicate whether these differences have biological significance and provide reasons, analyze the relationship between the relevant differences and the test product, rather than just listing the items with statistical differences. Additionally, for subchronic toxicity tests involving implantation contact with the test substance, the basis for determining the implantation dose should be provided. For example, in cases where animals can tolerate it, the recommended sample implantation dose is 50-100 times the intended human clinical dose.

Article 58 of the "Regulations on the Registration and Management of In Vitro Diagnostic Reagents" (Decree No. 5) stipulates: "If there are changes in the content stated on the registration certificate and its attachments, the applicant shall apply to the original registration department for changes in the license application, including changes in the main material suppliers of antigens, antibodies, etc." The interpretation of this provision is as follows: 1. Changes in the license application pertain only to the content stated on the registration certificate and its attachments, specifically the changes in the main raw material suppliers clearly stated in the appendix of the product's technical requirements. Changes in main raw material suppliers not explicitly stated in the registration certificate and its attachments, such as in the case of Type II in vitro diagnostic reagents where there is no appendix in the product's technical requirements, require the applicant to conduct their own research and quality control when changes occur in the main raw material suppliers without the need to apply for changes in the license application. 2. The situation of "changes in main material suppliers of antigens, antibodies, etc." is limited to changes in the main raw material suppliers. Changes in the main raw materials themselves, such as changes in the antibodies themselves, do not fall under the category of changes.

According to the "Guiding Principles for the Technical Review of Medical Device Software Registration," significant software updates (i.e., changes in software release versions) require reporting changes in the license application. For minor software updates, manufacturers can control them through the quality management system without the need for registration changes. The relevant declaration materials should be submitted at the next registration (registration change and renewal registration).

Dental adhesives are used for securing removable partial dentures, overlay dentures, and other types of dental restorations. Products with different structural compositions should be classified into different registration units. For example, post-type, bar-clip type, attachment type, and ball cap type attachments should be classified as different registration units.

In the overview information of the registration application materials for in vitro diagnostic reagents, Part (V) of the summary content, often overlooked, is a summary of the innovativeness of the intended product and the situation of similar products already on the market. This includes the approval status of similar products on the market domestically and internationally, the technical methods and clinical applications of related products, and the similarities and differences between the registered product and similar products domestically and internationally. For newly developed in vitro diagnostic reagent products, literature data should be provided on the relationship between the analyte and the expected clinical indications. If similar products are already on the market domestically or internationally, the applicant should specify the registrant, product name, and quantity of similar products already on the market and compare the differences and similarities between the proposed product and similar products in terms of technical methods, product performance, clinical applications, etc., including the clinical use domestically and internationally. If there are no similar products on the market domestically or internationally, or if the application product changes the conventional expected use and has new clinical diagnostic significance, the applicant should provide literature data on the relationship between the analyte and the expected clinical indications, including relevant guidelines, expert consensus, etc.

According to the provisions of the GB/T 16886 series standards, when conducting biological experiments, the selected extraction media should be suitable for the characteristics and use of the final product as well as the purpose of the experiment, taking into account the material chemical properties of the device materials, extractable substances, or residues. For cytotoxicity tests, as serum-containing culture medium is a necessary medium that supports cell growth in the test system and has the ability to extract both polar and non-polar substances, it should be considered as the preferred extraction medium for cytotoxicity tests. In this case, only one extraction medium containing serum culture medium can be used. For sensitization tests, irritation or intracutaneous reaction tests, acute systemic toxicity tests, etc., consideration should be given to selecting both polar and non-polar extraction media. For genetic toxicity tests, according to the GB/T 16886.3 standard, when appropriate, two suitable extraction solvents should be used—one polar solvent and the other non-polar solvent or a liquid suitable for the nature and use of medical devices, and both solvents should be compatible with the test system.

The selection of typical products includes all raw materials and components, the most complex structure, the highest risk, and the performance that can cover other models of this registration unit, for full project registration testing. For products within the same registration unit, it is recommended to conduct full project testing on the model with the largest membrane area, and then test the physical performance of the model with the smallest membrane area. All components should undergo registration testing, especially those with special structures and performance. After completing the testing of typical products, differential testing can be conducted on other models within the same registration unit.