All members of the Icelandic Dentist Association and the Icelandic Dental Technician Association who had registered e-mail addresses, received the questioner so the sample was self-selected as the participants selected themselves by responding to the survey.
Úrtakið var sjálfvalið þar sem þátttakendur völdu sig sjálfir með því að svara könnuninni en tekið var fram að engum væri það skylt.