Patients' expectations of orthodontic treatment: part 1 - development of a questionnaire.
OBJECTIVE: The development of a questionnaire to measure patients' and their parents' expectations before orthodontic treatment, and to test the reliability and validity of this measure. DESIGN: A two-stage methodology, with open-ended interviews to identify themes and concepts followed by development and testing of the questionnaire. SETTING: GKT Orthodontic Department, King's College Dental Hospital. SUBJECTS: The sample consisted of 140 participants, 70 patients aged 12-14 years, who had been referred to the orthodontic department for treatment. One parent of each patient was also recruited. MATERIALS AND METHODS: The study was in two phases. In the first phase 30 participants (15 new patients and their 15 parents) participated in open-ended interviews, which were analysed qualitatively. Information from these interviews was used to construct a questionnaire. During the second phase, the questionnaire was piloted on 10 participants, five new consecutive patients and their parents. The questionnaire was then distributed to 174 subjects (87 new patients and their 87 parents). Seventy-eight subjects (39 new patients and their 39 parents) completed the questionnaire before their orthodontic consultation. Another 96 subjects (48 new patients and their 48 parents) were invited to complete the questionnaire prior to and at their orthodontic consultation. Test-retest analysis was conducted on 22 participants (11 patients and their 11 parents), who completed the questionnaire previous to and at their orthodontic consultation, and contributed to the psychometric validation of this questionnaire. MAIN OUTCOME MEASURES: A questionnaire was devized using the key themes and concepts identified in the open-ended interviews. As a result, 10 questions, some with sub-questions were constructed using a visual analogue scale as the response format. RESULTS: The questionnaire developed had good face validity. Internal consistency of the questionnaire using Cronbach's alpha, produced an overall inter-item reliability > 0.7 along with item-total correlations > 0.3 in over 50% of questions. Test-retest reliability was statistically significant using Spearman's correlation. CONCLUSION: This study provides a valid and reliable measure of orthodontic expectations in participants aged 12-14 years and their parents.