215 ILCS 110/10
"Participating dentist" means a dentist licensed in Illinois to practice dentistry, and who, by written agreement with a dental service plan corporation undertakes to furnish dental service to the plan's subscribers and their covered dependents and to abide by its by-laws, rules and regulations.
(from Ch. 32, par. 690.10)
(Source: Laws 1965, p. 2179.)