抄録
Background: Guided bone regeneration (GBR) therapy using a titanium mesh (TM) is expected to be an effective bone regenerative technique capable of achieving a 3-dimensional massive bone augmentation with a solid, flat and regular cortical layer and, consequently, enhancing the indication of implant therapy and quality of clinical outcomes. Despite many clinical and animal observations indicating TMʼs favorable osteoblastic compatibility, the cell-biological advantages of TM as a GBR membrane are not fully addressed or understood.
Objectives: The purpose of this in vitro study is to examine whether cultured osteoblasts generate a mineralized matrix with superior structural and mechanical properties on a TM and to determine the biological advantages of the TM as a membrane material for use in bone regeneration therapy.
Methods: The surface roughness of a TM was measured using laser microscopy. Rat femoral bone marrow-derived osteoblasts were seeded on polystyrene (PS) which categorized into bioinert material as titanium, and on the TM. The surface morphology and development of calcifications of the cultured mineralized matrix at day 28 were qualitatively analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The micro hardness and elastic modulus of the cultured mineralized matrix at day 28 were measured by nanoindentation.
Results:Ra, Ry and Sm values on the TMʼs surface were 0.10 ± 0.02μm, 0.7 ± 0.1μm and 4.4 ± 1.0μm, respectively. SEM observation revealed that the mineralized matrix at day 28 of the osteoblastic PS culture was porous and exposed a fibrous network and globular extracellular matrix. On the other hand, the mineralized matrix on the TM showed a dense and flattened lamellar structure without exposure of fibrous and globular components. An identical lamellar mineralized matrix was universally and evenly spread on the TM. The Ca/P atomic ratio in the matrix was 1.28 in contrast with 0.87 in the polystyrene culture. The mineralized matrix cultured on the TM for 28 days was four times harder and stiffer than that on the PS.
Conclusion:Rat femur bone marrow-derived cultured osteoblasts produced mineralized matrix with a denser structure and higher biomechanical strength on the micro-roughened surface of the TM than on the PS. This in vitro study helped to indicate the cell-biological mechanism underlying the excellent bone augmentation effects of TM.
