[Discussion about Supervision Model of Customized Medical Device].

Customized medical devices differentiate in product design, manufacturing, usage, and a few other aspects in the product's life cycle. Customized medical devices should have special regulatory requirements. Through introducing the relevant regulations, policy and control measures for customized medical devices in different countries, this article intends to summarize the common characteristics of customized devices. Also, considering the development of fixed denture and medical device regulations in China, we aim to provide reference for investigators by discussing regulatory categorization in the definition and management, quality system, clinical evaluation and the post-marketing use of customized medical devices in our country.

[Biomechanical study on restorative methods of unilateral maxilla based on finite element analysis].

This paper is to report our study in which the differences between prosthetic restoration and surgical reconstruction using traditional clasp retention technology were analyzed based on three-dimensional finite element methods in our laboratory. Firstly, the maxillary unilateral defect model was developed using medical image processing software MIMICS. Secondly, the prosthesis was generated by mirroring technology. The clasp was designed according to the methods raised by Aramany. Then, the stress distribution of maxilla was calculated by simulating occlusion. According to the results, after osseointegration of surgical reconstruction, stresses of unaffected abutments were reduced significantly, and less stress of junction occurred near zygoma of affected side, which were all less than stresses of prosthesis restoration. Thus, removing the clasp of surgical reconstruction increased the stresses of unaffected abutments. The stress trends of maxillary components were different between prosthetic restoration and surgical reconstruction. Surgical reconstruction is better than prosthesis restoration in protection of the abutments. Clasp can alleviate the occlusal burden of maxilla. Varieties of retentive technologies can be considered in prosthesis restoration. The surgical reconstruction is more conducive to rehabilitate unilateral maxilla biomechanically in clinic.

Pre-Registration Assessment of Bone-Filling Products.

The use of bone-filling material to repair bone defects and fix implanted bone grafts is a developing area in medicine. Investigators can evaluate bone-filling materials through use of several indices to make comparisons and to determine suitability for application in humans1 . However, it is quite difficult to transform their discovery into practical use, because the viability of the studied material might require examination of all aspects of properties. In addition, for a material to become a product, a complete procedure involving a declaration, registration, and approval is necessary. This article introduces the technical indices that the investigators and reporters should provide in their declaration and registration data to meet the relevant standards in China. The indices include physical and chemical properties, biocompatibility, biosecurity, pre-clinical animal model tests, sterilization and disinfection, product duration, and packaging. Full consideration of all possible indices is crucial to realize the transformation from a designed product to a commercial medical device, which requires effective interaction between clinicians and engineers.

[Design and in vitro evaluation of self-microemulsifying drug delivery systems for piroxicam].

Self-microemulsifying drug delivery systems (SMEDDS) were developed to overcome the problems of delivery and administration of piroxicam, a drug with low bioavailability and gastrointestinal irritation, The in vitro properties of it were assessed. The solubility of piroxicam in several oils and surfactants was determined, and the compatibility of various oils and surfactants was investigated. Ternary phase diagrams were constructed to optimal area of microemulsion, and the influence of different oily phases, surfactants and co-surfactants was studied. The droplet size and dissolution of optimal formulation were determined to prove that the dosage form is a useful delivery system for piroxicam. In the optimized piroxicam SMEDDS, cinnamic alcohol was selected that gave the maximal solubility to piroxicam. Labrafil M 1944CS, Cremophor EL and Transcotol P were used as oils, surfactant and co-surfactant, respectively. Droplet size and distribution of three piroxicam SMEDDS formulations were (32.2 +/- 5.0), (40.1 +/- 6.4), (81.9 +/- 12.2) nm individually. And the releasing of piroxicam was rapid and complete. The optimized SMEDDS for piroxicam was obtained.