Comparison of dental health data obtained from questionnaires, interviews and clinical examination

abstract – Validity of response to a postal questionnaire, answered by 216 persons, was studied by comparing data from the respondents on the occurrence of dentures and on the number of remaining teeth with data recorded by a clinical examination. Information, collected in a personal interview on gingival disease, was compared with clinical records. Reliability was studied by examining the agreement between data from the questionnaires and from the interviews concerning time interval since the last dental visit.
The information on the occurrence of dentures proved to be highly valid, while the reported number of teeth were less likely to conform with the clinical records. A slight tendency towards overreporting of remaining teeth was found. Conceivably, the greatest proportion of overestimates was caused by confusion concerning the counting of fractured teeth and roots. Gingival disease was markedly underreported. At the clinical examination, all subjects with some teeth showed signs of gingival disease, but only every fourth person reported having experienced "gum disease". Information about time interval since the last dental visit was found to be reliable.