A-dec 400 Dental Chair Instead of sacrificing ergonomic access to the oral cavity for patient comfort, get both with the A-dec 400 dental chair. And when you add robust construction, contemporary styling, and left/right versatility, you gain a system that is the best long-term value available on the market. A-dec 400, a thoughtful approach to dental system design. Take a look at the A-dec 400 Product Brochure