ABSTRACT
In this work, a novel and simple bone morphogenetic protein (BMP)-2 carrier is developed, which enables localized and controlled release of BMP-2 and facilitates bone regeneration. BMP-2 is localized in the gelatin methacrylate (GelMA) micropatterns on hydrophilic semi-permeable membrane (SNM), and its controlled release is regulated by the concentration of GelMA hydrogel and BMP-2. The controlled release of BMP-2 is verified using computational analysis and quantified using fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) diffusion model. The osteogenic differentiation of osteosarcoma MG-63 cells is manipulated by localized and controlled BMP-2 release. The calcium deposits are significantly higher and the actin skeletal networks are denser in MG-63 cells cultured in the BMP-2-immobilized GelMA micropattern than in the absence of BMP-2. The proposed BMP-2 carrier is expected to not only act as a barrier membrane that can prevent invasion of connective tissue during bone regeneration, but also as a carrier capable of localizing and controlling the release of BMP-2 due to GelMA micropatterning on SNM. This approach can be extensively applied to tissue engineering, including the localization and encapsulation of cells or drugs.
ABSTRACT
STATEMENT OF PROBLEM: Use of custom tray and tray adhesive is clinically recommended for elastomeric impression material. However there is not clear mention of drying time of tray adhesive in achieving appropriate bonding strength of tray material and impression material. PURPOSE: This study is to investigate an appropriate drying time of tray adhesives by evaluating tensile bonding strength between two types of polyvinylsiloxane impression materials and resin tray, according to various drying time intervals of tray adhesives, and with different manufacturing company combination of impression material and tray adhesive. MATERIAL AND METHODS: Adhesives used in this study were Silfix (Dentsply Caulk, Milford, Del, USA) and VPS Tray Adhesive (3M ESPE, Seefeld, Germany) and impression materials were Aquasil Ultra (monophase regular set, Dentsply Caulk, Milford, Del, USA) and Imprint II Garant (regular body, 3M ESPE, Seefeld, Germany). They were used combinations from the same manufacture and exchanged combinations of the two. The drying time was designed to air dry, 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 25 minutes. Total 240 of test specimens were prepared by auto-polymerizing tray material (Instant Tray Mix, Lang, Wheeling, Il, USA) with 10 specimens in each group. The specimens were placed in the Universal Testing machine (Instron, model 3366, Instron Corp, University avenue, Nowood, MA, USA) to perform the tensile test (cross head speed 5 mm/min). The statistically efficient drying time was evaluated through ANOVA and Scheffe test. All the tests were performed at 95% confidence level. RESULTS: The results revealed that at least 10 minutes is needed for Silfix-Aquasil, and 15 minutes for VPS Tray Adhesive-Imprint II, to attain an appropriate tensile bonding strength. VPS Tray Adhesive-Imprint II had a superior tensile bonding strength when compared to Silfix-Aquasil over 15 minutes. Silfix-Aquasil had a superior bonding strength to VPS Tray Adhesive-Aquasil, and VPS Tray Adhesive-Imprint II had a superior tensile bonding strength to Silfix-Imprint II at all drying periods. CONCLUSION: Significant increase in tensile bonding strength with Silfix-Aquasil and VPS Tray adhesive-Imprint II combination until 10 and 15 minutes respectively. Tray adhesive-impression material combination from the same company presented higher tensile bonding strength at all drying time intervals than when using tray adhesive-impression material of different manufactures.
