In chapter 4 of "Night", how did Elie initially avoid losing his gold crown?

After work one day Elie is ordered to report to the dentist after he finishes his meal.  Elie tells the guard that he "doesn't have a toothache."  He has to report to the dentist anyway and when he arrives the dentist and asks him what the dentist intends to do.  The dentist informs Elie that he is simply going to pull out his crown.  Elie avoids this by telling the dentist that he is ill.  He asks the dentist to wait a few days.  The dentist says okay, but tells Elie to come back in a few days and "don't wait for me to call you!" 

Elie actually went back a week later with the same excuse and the dentist once more granted him a reprive.  Elie then learns that after the second visit the dentist's office has been closed and the dentist was arrested.