Method and apparatus for fabricating an oral appliance are described for correcting malocclusions on a dentition of a subject. A three-dimensional representation of the dentition may be captured and a free-form structure having a lattice structure which matches at least part of a surface of the dentition is generated. The lattice structure defines a plurality of open spaces such that the free-form structure is at least partially transparent. The lattice structure may then be manufactured by impregnating or covering a coating into or upon the lattice structure such that the oral appliance is formed.