Outlining the morphological characteristics of acceptable occlusion.
The aim of this study was to outline the definitions of a morphologically acceptable occlusion in young adults that could be applied to assess the outcome and effectiveness of orthodontic treatment. The opinions of Finnish orthodontists and general practitioners were investigated for this purpose. A semi-structured questionnaire was sent to all health centres where at least one orthodontist was employed (n=37), to health centres without any orthodontist (n=31), to private orthodontists working as consultants (n=12) and to orthodontists working at university dental clinics (n = 13). The criteria for moderate and little orthodontic treatment need in the Need of Orthodontic Treatment Index (NOTI) and the Index of Orthodontic Treatment Need (IOTN) were chosen to describe the basic characteristics of occlusal acceptability. The questionnaire was returned by 76 subjects (82%). The respondents' views on an acceptable occlusion in young adults were not totally in line with the chosen definitions. Only 16% of the respondents accepted the definitions of both indices as such; the criteria in NOTI were accepted by 25% and those in IOTN by 21% of the respondents. Functional considerations of the occlusion were the main reasons for the desire for further details in the description of an acceptable occlusion. Crossbites with a discrepancy between retruded contact position and intercuspal position were the least accepted anomalies. The opinions were statistically significantly associated with the level of the respondents' orthodontic education and their type of employment. We conclude that the selected definitions of NOTI and IOTN can serve as a basis for the characteristics of a morphologically acceptable occlusion in young Finnish adults, but measures of the functional aspects of occlusion must be added for studies on the outcome of orthodontic services.