Degrazia FW, et al. - Physicians designed this study to assess physicochemical properties, long-term microtensile bond strength, and cytotoxicity of methacrylate-based adhesive containing boron nitride nanotubes (BNNTs) as fillers. Without decreasing viability of fibroblast cell growth, incorporating boron nitride nanotubes up to 0.1 wt% into dental adhesive increased the long-term stability to dentin. Therefore, the use of BNNTs as a filler could decrease failure rate of current dentinal adhesives.