Traditionally, owner-operators have dominated the profession. In 1991, 91 percent of practicing dentists had an ownership stake in their practices, with 67 percent serving as the sole proprietor. Today, things are changing. By 2012 the proportion of dentists who owned their practices had dropped to 85 percent, with just 57 percent being solo practitioners. As I wrote in 2009, it’s tough to run this kind of operation. Owner-operators must buy their own equipment, supplies, and malpractice insurance; pay for rent and staff; and operate the kind of small business that can’t take much advantage of economies of scale.