Biomedical subjects

Dongyun Gu

Publications and source records attributed to Dongyun Gu.

4 recordsLinked to original sources

PubMed2004

[Morphological analysis of acetabulum bony curved surface].

By using the reverse engineering (RE) technology, the mesh surface model of acetabulum was reconstructed by triangulation. Based on this kind of model, the local morphological analysis (LMA) and global morphological analysis (GMA) could be processed. The fitting minimal quadric surface method was applied to calculate the curvature of any point on the acetabulum bony surface, the local morphological character of its surface could be acquired, and its global surface character could be determined by GMA. The results showed that the acetabulum bony surface is elliptical surface, and its three eigenvalues (lambda1, lambda2, lambda3) relations on the three axes (x, y, z) are as follows: lambda1 is short than lambda2 and lambda3, lambda2 is close to lambda3.

Acetabulum↗

PubMed2004

[A study on new computer-aided modeling method of hip joint].

The main reason of invalidation of prosthetic hip joint is the prostheses flexibility and shift, dislocation and disjunction. Promoting the long time stability of the prostheses is the key of improving the long term hip joint replacement effect. Former research work was focused on the upper segment of femur, and assumed the acetabulum cup to be a spheric concave, and the external form of acetabulum prostheses was basically semi spheric. This paper presents a method of acquiring the point data on the surface of the hip bone using the reverse engineering technology. By analyzing the acetabulum surface fitting error we use rotating elliptical surface to fit the acetabulum surface, together with the optimal technique to build up the CAD model of acetabulum surface. We compare the fitting error between the sphere fitting and rotating elliptical surface fitting and get the result that the rotating elliptical surface fitting error is smaller than the sphere fitting error, and the rotating elliptical surface can describe the shape of the acetabulum better.

Acetabulum↗

PubMed2003

[Morphologic features of the acetabulum bone joint area].

The research on the morphology features of the acetabulum bone joint surface area would be helpful to establishing the acetabulum 3D model for the purpose of the biomechanical analysis of hip joint, and therefore might have its important clinical significance. However, in former studies, the acetabulum was simply considered as a semi sphere. In this study, based on the acetabulum 3D-point data acquired by the 3D laser surface scanner and the reverse engineering technology together with the optimal fit algorithm, two kinds of best-fit model were achieved by a sphere surface and a rotating elliptical surface respectively approaching to the acetabulum bone joint surface. Both fitting errors were then compared and analyzed. The results showed that the fitting error of the rotating elliptical surface was significantly less than that of the sphere surface (P < 0.001). The average radius of fitting sphere was 24.37 +/- 2.22 mm and the average long axis of fitting rotating elliptical surface was 26.02 +/- 2.76 mm while its short axis was 24.17 +/- 2.16 mm. These findings would be helpful to our new recognition of the acetabulum since they were results of the first quantitative analyses for the acetabulum bone surface and also might serve as an important reference base in its further studies and application.

Acetabulum↗

PubMed2002

[An experiment study on repairing residual dental root with a horn-shaped orifice by different materials].

When a traditional method is used to repair residual dental root with horn-shaped orifice, this kind of dental root often has to be extracted since the success rate in clinic is very low. The main reason is that the stress often concentrates on the neck and root apex, therefore the wall at the orifice is too thin to bear this kind of pressure. A new repairing method is proposed trying to preserve the residual dental root with horn-shaped orifice. Then compare the anti-fracture ability of this kind of tooth with that of no repairing. The results show that it is very effective to prevent the fracture of residual dental root repaired by chemical hard synthetic resin followed by making the post and core. However, there is no obvious difference between non-repaired and residual dental root groups repaired by traditional glass ionic adhesives. The results also provide the great possibility to preserve the residual dental root with horn-shaped orifice in clinic.

Dental Restoration, Temporary↗