Dennis graduated from the University of Illinois at Chicago’s College of Dentistry in 1974 and has been practicing dentistry in Yorkville ever since. He is highly experienced in all phases of dentistry and enjoys treating all patients from children to seniors. Dennis grew up on Chicago’s south side near Midway Airport and completed his undergraduate studies at the University of Illinois Urbana-Champaign. Currently he resides in Winfield, IL with his wife Karen, and cat Klau. Dennis also has two grown children, Kate, an avid marathon runner and Mike, who recently graduated dental school himself. When he’s not in the office, Dennis can be found cheering on his Illini and the Cubbies! Dennis is a member of the American Dental Association, the Illinois State Dental Society, and the Fox River Valley Dental Society. Most recently, Dr. Kostal was voted the Best Dentist in Yorkville on the Yorkville Patch website.