Assessing malocclusion--the time factor.

Assessment of occlusal status for orthodontic purposes may be undertaken by subjective assessment or by means of an index of occlusion. The assessment method should be reproducible and should achieve the intended outcomes. This study investigated another possible modifying factor--performance over time. Photographs and dental casts of 45 subjects at 12 years of age were compared with follow-up records at 16 years of age. No orthodontic intervention had occurred during the 4 years. Subjective severity assessments and Aesthetic Component (AC) scores of the Index of Treatment Need (IOTN) for first and second series records were made by four orthodontists. Scores of the Dental Aesthetic Index (DAI) and Dental Health Component (DHC) of the IOTN were made by one of the authors. Implications for hypothetical decisions to treat were considered. There was a significant reduction in the subjective severity and DAI scores across the whole sample and in the mixed dentition subgroup. There was a non-significant reduction in the AC (IOTN) scores across the whole samples, but there was a significant reduction in the AC (IOTN) scores in the mixed dentition subgroup. The DHC (IOTN) categorisations proved to be more stable over the period of study.