Long-term follow-up of early treatment of unilateral forced posterior cross-bite. Orofacial status

Twenty-nine subjects, 20 years old on average and all treated at 4 years of age for unilateral forced posterior dento-alveolar cross-bite by grinding or by expansion of the upper dental arch, were clinically examined to evalu ate the long-term effects of their treatment. The frequency of successful t reatment-indicated as stable correction of the cross-bite-by means of only 1 treatment sequence was 59%; by grinding, 57%; and by expansion, 60%. The 18 subjects that had only been treated at the age of 4 years formed the 'ea rly group' in our study. Eleven of our subjects had been retreated later in the mixed or permanent dentition because of a relapse of the unilateral fo rced posterior cross-bite and formed the 'late group'. A significantly high er frequency of mouth breathing, breathing obstacles, and snoring was found in this group. According to our clinical investigation, 2 of the subjects in our cohort still had a unilateral forced posterior cross-bite. Our findi ngs regarding masticatory performance, bite force, and endurance showed no significant differences between the initial cross-bite and the healthy side s or between the early and the late group subjects, which showed that the m asticatory function of the treated subjects was symmetrical. Grinding and e xpansion treatments seem to display similar success rates in the long-term regarding correction of unilateral posterior forced cross-bite.