A chair for supporting a body of a user in a substantially upright position relative to a vertical-axis; the chair includes a frame, a chest-support, a seat and at least one knee-support. In a preferred embodiment, the chair includes a tray configured to hold items/tools such as dentist equipment. The chair is useful for supporting the body of the user who needs to be seated for a prolonged period of time, to prevent un-comfort associated with the same.