A randomized controlled study of early headgear treatment on occlusal stability--a 13 year follow-up.

The purpose of this investigation was to assess the long-term occlusal stability in a group treated early with headgear (HG) compared with a control group. The total study group comprised 68 children (40 males and 28 females) aged 7.6 years (standard deviation 0.3), randomly divided into two groups of equal size. In the first group, HG treatment was initiated immediately, while in the control group only minor interceptive procedures were performed during the follow-up period. Fixed appliance treatment, if needed, including extraction of permanent teeth due to crowding, was undertaken after the completion of early treatment. The records were available from the start of the early treatment and at follow-up after 2, 4, 8, and 13 years. The US-weighted Peer Assessment Rating (PAR) Index, graded according to the severity of malocclusion, was used to evaluate occlusal stability. Little's Irregularity Index (LII)and intercanine distance in the lower arch were measured at all time periods. The Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) scores was used for evaluation of dental aesthetics at the last follow-up. Parametric tests were applied for statistical analyses, except for the evaluation of aesthetics, where a non-parametric test was used. No significant differences were found when long-term stability between the HG and control groups was evaluated at the 13 year follow-up. Lower PAR scores were observed in patients treated without extraction of teeth. A greater irregularity in lower incisor alignment before treatment was found in subjects later treated with extractions. The findings of this study seem to suggest that treatment timing has only a minor influence on stability.