People who live with a practicing alcoholic or addict are in a horribly difficult situation. Those folks have often tried numerous schemes to control the CD person's drinking or using, all of which have ended in failure and frustration. As with the active addict, to acknowledge they have a problem that they've proven repeatedly they cannot solve is simply not possible for most people to accept.
Staff people, family members, and colleagues all have vested interests that are threatened by the presence of chemical dependency in a dentist. Staff might lose their jobs if the dentist loses his or her license. Family members' financial security is on the line. Colleagues do not want the embarrassment of acknowledging there may be "one of them" in their profession. Those interests all fuel denial and enabling.
People around a chemically dependent person typically exhibit behaviors that work to maintain denial of the problem, resulting in perpetuation of the chemical dependency. For example, the spouse who calls the office to report the dentist has a touch of the flu to explain an absence due to a Monday morning hangover is just setting the stage for the next incident. The CD dentist is bailed out and need not face a consequence that could have helped gradually break through his or her wall of denial.
As 12 step programs work well for recovering addicts and alcoholics, they work well for enablers and codependents. Groups such as Alanon and Alateen have tailored the 12 steps to the needs of codependents. Addictions counselors are also excellent resources for treatment of codependence.