A biased palatal bone expander attaches directly to the palatal bone in the roof of the mouth of a patient. The expander has dual, biased, mutually parallel rods. The rods extend from coaxial tubes and have coaxial springs. The expansion of the springs urges the rod outwardly from the center of the expander thus widening the maxillary arch incrementally without a connection upon the teeth. The tubes and rods each attach to two mutually parallel bars perpendicular to the rods. Each bar has two opposite ends with an eyelet upon each end. The eyelets receive screws for securing the expander to a patient. Additionally, the appliance may include a thermoformed shell that a surgeon or orthodontist uses to guide positioning the appliance for installation.
