Orthodontic treatment in the General Dental Service assessed by the Occlusal Index

As with all other aspects of health care, orthodontic treatment should be evaluated in as objective a manner as possible. In this study, the models of a sample of 256 patients treated by appliance therapy in the General Dental Service were examined. The Occlusal Index was first refined and variability in its use due to articulation and measurement errors was assessed. It was then used to quantify occlusal status both before and after treatment, and thereby monitor changes brought about by treatment. The mean Occlusal Index score at the beginning of treatment was 9.9. At the end of treatment, the mean score had dropped to 5.5. There was wide variation among individual cases, but some reduction was found in 88 per cent of instances. In 56 per cent of cases the reduction ranged up to 6 units, while in 29 per cent of cases the reduction was 6-12 units. However, in cases which started with a marked malocclusion, only about one-third showed a sizeable improvement. In about one-third of all cases there was little improvement in the malocclusion. While there is room for further refinement of the Occlusal Index to increase its usefulness in quantifying occlusal status brought about during orthodontic treatment, the present findings provide a basis for future comparisons.