A course can be an introduction to a history of a development of a specialty of orthodontics.
Personalities may be involved in a development of a specialty.
An introduction can be to a history of a development of a specialty of orthodontics.
(Specialty practice) can be with knowledge of an interrelationship.
A medical specialty may be concerned with a prevention of disorders.
Work may be undertaken by a number of (specialty subcontractors).
(Specialty architects) may be engaged for designing a type of building.