Need for preventive and interceptive intervention for malocclusion in 3--5-year-old Finnish children

Posterior crossbite--treatment and stability

Posterior crossbite is defined as an inadequate transversal relationship of maxillary and mandibular teeth. Even when eliminating the etiologic factors, this malocclusion does not have a spontaneous correction, and should be treated with maxillary expansion as early as possible. This treatment aims at providing a better tooth/skeletal relationship, thereby improving masticatory function, and establishing a symmetrical condyle/fossa relationship. Should posterior crossbite not be treated early, it may result in skeletal changes, demanding a more complex approach. Additionally, an overcorrection expansion protocol should be applied in order to improve the treatment stability. Although the literature has reported a high rate of relapse after maxillary expansion, the goal of this study was to demonstrate excellent stability of the posterior crossbite correction 21 years post treatment.

Follow-up control of patients with unilateral posterior cross-bite treated with expansion plates or the quad-helix appliance

The aim of this study was to evaluate the long-term stability of the occlusion after correction of posterior cross-bite with either a removable expansion plate or a quad-helix appliance and to compare the transversal development of the jaws in the plate group, the quad-helix group and a control group. At the start of treatment there were 22 children in each of the treated groups. Two children in the plate group and 1 child in the quad-helix group discontinued the treatment. Two children treated with the quad-helix appliance and 1 child in the plate group could not be reached for the follow-up registration, so the collective finally consisted of 30 boys and 27 girls: 19 subjects in the plate group, 19 in the quad-helix group and 19 controls. The treatment groups were studied with the help of plaster models before treatment, immediately after treatment and at the last registration about 5.5 years after treatment. The control group was studied with the help of plaster models on 2 occasions, at the mean age of 8.8 years and 15.9 years respectively. This was about the same age as the first and the last registrations in the treatment groups. In all children, the posterior cross-bite was corrected by the end of the treatment. At the last registration, the corrected posterior cross-bite had relapsed in 1 child in the plate group and in 3 children in the quad-helix group. The degree of expansion was similar for both groups. The mean treatment time was longer in the plate group than in the quad-helix group: 12.5 months and 7.7 months respectively. Despite a transversal expansion in the treatment groups, the width of the maxillary dental arch did not reach the mean width in the control group, and even at the last registration the width of the maxillary dental arch was significantly greater in the control group than in the treated groups. The conclusions of this study are: 1. The long-term treatment effect in children with posterior cross-bite was somewhat better when they were treated with the removable expansion plate in comparison with treatment with the quad-helix appliance. 2. Both immediately after treatment and at the last registration 5.5 years later, the width of the maxillary dental arch was significantly greater in the control group than in the plate group or the quad-helix group while the width of the mandibular dental arch was equal in all 3 groups.

Need for interceptive intervention for malocclusion in 6-year-old Finnish children

The need for interceptive intervention for malocclusion was studied in a sample of 839 Finnish children aged 6 years. The children had participated in an organized preventive orthodontic program, and nearly 10% of them had received preventive or interceptive orthodontic treatment at the age of 3-5 years (stage I of the preventive orthodontic program of the author). Orthodontic intervention was estimated to be needed for 5.9% of the children due to crossbite of the permanent central incisors, to crossbite or scissors-bite of the permanent first molars, to ectopic eruption of the permanent first molars, to numerical variation of the permanent incisors, or to functional open bite. The need for further inspection in order to follow-up development of the dentition was noted in 2.7% of the children. The indications occasioning this consideration were initial severe crowding, extreme incisal overjet, and early loss of the primary mandibular canines. The relatively low prevalence rates seemed to indicate advantageous results of the preventive and interceptive orthodontic measures.