Design of Collagen-Based Sponge Device for Use in Oral Surgery

This study aims to develop various types of collagen devices for use in oral surgery. The targets are the sheet-shaped sponges to cover mucosal defect wounds (product-1) and gingival defect wounds (product-2) and the cylindrical sponge to fill tooth extraction sockets (product-3). The sheet-shaped sponges were manufactured by freeze-vacuum drying the aqueous solution of collagen (Col) and heat-denatured collagen (Col’) at a composition ratio of 2/1, 1/1 or 1/2. Both surfaces of the sheet-shaped sponge were treated by ultraviolet (UV) irradiation for 5, 10 or 15 minutes to introduce intermolecular crosslinks between collagen molecules. The elution behavior of each collagen sponge was investigated by immersing the sponge in water for a predetermined time and then by measuring the weight change. The collagen sponge composed of Col and Col’ with a composition ratio of 2/1 that was treated by UV irradiation for 15 minutes showed very slow elution properties. This sheet-shaped sponge is the top candidate for product-1. The collagen sponge composed of Col and Col’ with a composition ratio of 2/1 that was treated by UV irradiation for 5 minutes showed slightly fast elution properties. This sheet-shaped sponge is the top candidate for product-2. Next, the cylindrical sponge was manufactured by freeze-vacuum drying the aqueous solution of Col and Col’ at a composition ratio of 2/1. Both sides of the cylindrical sponge were treated by UV irradiation for 15 minutes. This sponge showed initially fast elution properties and subsequent very slow elution properties. This cylindrical sponge is a good candidate for product-3. As a basic design, the sheet-shaped sponge and the cylindrical sponge should be biodegraded and absorbed by the time new tissue formation is completed.