FAQ

The administrative counterpart should analyze the applicability of the requirements for shear viscosity, intrinsic viscosity number, weight average molecular weight, and molecular weight distribution coefficient in YY/T 0308 to the product under application. When the relevant requirement is not applicable to the product under application or may not be measured in the final product, the quality control data on the relevant properties of the intermediate product without cross-linking treatment should be provided in the product research data.

An in-vitro degradation test is required for injectable sodium hyaluronate gel for plastic surgery. Please refer to YY/T 0962 for the specific requirement, so as to guarantee quality control of the degradation performance of the sodium hyaluronate gel. It is recommended to set multiple time points for observation until the sodium hyaluronate gel is observed to be completely degraded, and upper & lower limits should be developed for the degradation levels at different time points. In the in vitro test, accelerated degradation can be achieved by adjusting test conditions like the concentrations of degrading enzymes.

If the implantable drug-supplying device has a coating, information on the chemical composition, purity and proportion of the coating should be provided. Relevant performance studies should be carried out, including qualitative and quantitative analysis (if applicable) of the coating, release performance (for the coating containing drugs)? use performance evaluation (such as lubricity of hydrophilic coating), shedding rate (if applicable), and safety evaluation documents etc. If the coating contains drugs, a safety and effectiveness study report on the drug added should also be provided, which should include at least: drug name, dosage; compatibility of the drug with the raw material used to make the device; the impact on human body caused by any changes of administration route, dosage, and drug storage conditions, etc. If the coating contains a biologically active substance, it is also necessary to provide the biosafety study data for the biologically active substance.

The administrative counterpart should fully consider the impact of processing aids on product performance during product design and development process. The quality control of processing aids should include at least the following contents: The use and selection basis of processing aids. Cleaning methods of processing aids, and the cleaning verification process. Controlling the residual processing aids of the product after cleaning. A study on the impact of residual substances on the safety and effectiveness of the final product. The acceptable limits of residual substances after final cleaning of the product should be discussed and demonstrated.

The following contents should be noted in the development of the performance requirements and performance indicators for the suture in suture anchors:

1. In the process of product design and development, the performance and performance indicator requirements of the suture should be determined from the perspective of the clinical needs and intended use of the product, and combined with the applicable site of the product and the specific use method, while comprehensively considering the quality control for the suture itself.
2. Suture anchor is usually used for the fixation of bones and soft tissues. It is class III medical device, different from the non-absorbable surgical sutures as class II medical device. The administrative counterpart should pay attention to the applicability of the standard when referring to relevant national or industry standards.

The sphericity of metal powder refers to the ratio that is the actual cross-sectional area of metal powder particles to the calculated area with the longest diameter on the cross section, and is a measure of the degree of similarity between particles and circles. Generally, it ranges from 0 to 1. The sphericity of a perfect circle is 1. The value of sphericity directly affects the flowability and bulk property of the particles. The higher sphericity of powder, more uniform of the powder spreading and more compact of the printed pieces. In the actual printing and processing, after each layer of powder spreading, the unprocessed powder will be used again, and part of the powder will be melted or sintered together, thus affecting the printing quality. Therefore, it is necessary to specify the sphericity of powder.

As an implantable medical device, the orthodontic anchor screw is implanted into jaw bone to resist the reaction force generated during tooth movement and assist the orthodontic activity of teeth. Unlike dental implants, which perform masticatory function and endure masticatory force for a long time, anchor screw only endures the force generated in the orthodontic process and is not a permanently implanted device. Therefore, the fatigue test may not be repeated for the orthodontic anchor screw made of the same materials as those of the marketed products.

The wear performance study of artificial joint products should be based on the entire joint system, and its wear performance is affected by many factors, such as joint surface materials that match the polyethylene components, product processing technology, radiation dose, shape design, specifications and dimensions. Therefore, even if the wear resistance of highly cross-linked ultra- high molecular weight polyethylene is better than that of ordinary ultra-high molecular weight polyethylene, it cannot demonstrate that the wear performance of the artificial joint products of highly cross­linked ultra-high molecular weight polyethylene is better than that of ordinary ultra-high molecular weight polyethylene.

For high-risk medical devices using polymer materials, the suppliers of the raw materials of products should be specified in the registration application dossiers. If there are two or more raw materials suppliers for the same raw material, the administrative counterpart should separately conduct design verification and validation of products made from raw materials of different sources to ensure that products made from raw materials of all sources are safe and effective as required. At the same time, the administrative counterpart should conduct separate procurement control of the raw materials provided by each supplier (the registration application dossiers generally include the quality agreement between the raw material supplier and the product manufacturer, the quality control criteria for the raw material, the raw material inspection report, and the qualification certificate of the raw material supplier, etc.).

Metal powder for Dental additive manufacturing should have stable physical and chemical properties. The purity of powder is one of the important indicators. In the process of powder preparation, the introduction of impurity elements such as oxygen, nitrogen and carbon should be used as an important verification aspect in terms of the preparation process. Take titanium alloy material as an example, with the increase of oxygen content, the plasticity of titanium alloy material, as a commonly used metal material in the preparation of dental restorations, will be greatly reduced, thus having serious influence on the hardness and mechanical properties of the final product. For metal powder of additive manufacturing, the oxygen content in chemical composition is an important factor affecting the printed piece. It is generally required that the oxygen content of titanium alloy powder should be controlled under 0.15%. Similarly, impurity elements such as nitrogen and carbon can also adversely affect the performance of the finished product and should be strictly controlled. Ceramic phase inclusions may be introduced during the preparation of powder due to melting and other factors. These refractory ceramic phase are mixed in the melting process of metal powder, which will prevent the metal powder from bonding well, easily causing internal defects of the printed body, and resulting in local performance degradation or even cracking of the printed body. Therefore

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If suture anchor, titanium plate with loop etc. are sterilized with ethylene oxide, acceptance criteria for ethylene oxide residuals should be established. The intended use and structure & composition of the product should be combined to fully consider the effect of ethylene oxide residuals on safety and effectiveness of product. Refer to GB/T 16886.7, to explain the process of establishing the acceptance criteria.