Long-term follow-up of early treatment of unilateral forced posterior cross-bite. Orofacial status. Longitudinal study on the effect of early interceptive treatment in 4-year-old children with unilateral cross-bite. Comparison of Hyrax and bonded expansion appliances. The effect of early interceptive treatment in children with posterior cross-bite. Two-point rapid palatal expansion: an alternate approach to traditional treatment. Skeletal and dental changes after maxillary expansion in the mixed dentition. A clinical investigation of the correction of unilateral first molar crossbite with a transpalatal arch. Slow maxillary expansion: a comparison between banded and bonded appliances.
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 evaluate the long-term effects of their treatment. The frequency of successful treatment-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 'early 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 forced posterior cross-bite and formed the 'late group'. A significantly higher 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 findings regarding masticatory performance, bite force, and endurance showed no significant differences between the initial cross-bite and the healthy sides or between the early and the late group subjects, which showed that the masticatory function of the treated subjects was symmetrical. Grinding and expansion treatments seem to display similar success rates in the long-term regarding correction of unilateral posterior forced cross-bite. To evaluate the results of early interceptive grinding and also the possibility of self-correction of unilateral cross-bite, 76 4-yr-old children with this malocclusion were divided into one treated and one untreated group. In the treatment group 50% of the children exhibited a normal transverse occlusion evaluated in the mixed dentition, at the age of 9. In the untreated group only 17% showed a spontaneous correction of the cross-bite. Among the studied dental variables the "max./mand. arch width difference" especially in the canine region was found to be a valuable predictor indicating whether cross-bite can be successfully treated in preschoolchildren by selective grinding. The results of this study support early treatment of unilateral cross-bite and gives the criteria whereby successful treatment by selective grinding may be expected. The majority of rapid maxillary expansion studies have reported the use of appliances with metal bands attached to the posterior teeth. Tooth extrusion, dental tipping, and an increase in the vertical dimension are often encountered, which may not coincide with treatment objectives. Bonded appliances using interocclusal acrylic may control the vertical dimension and expand the maxillary halves in a more bodily and symmetrical fashion. The purpose of this clinical trial was to determine, by radiographic analysis, the differences between a conventional banded expander (Hyrax) and a bonded acrylic expander. Fourteen patients who exhibited a need for expansion were enrolled in the study. The results suggest that the increase in the vertical dimension often seen with the more conventional Hyrax appliance may be minimized or negated with the bonded appliance. However, there appeared to be no significant difference between the amount of dental tipping or symmetrical expansion between the two appliances, as previously theorized. nan Rapid palatal expansion (RPE) causes separation of the lateral halves of the palate and traditionally has used four maxillary teeth as anchorage. The purpose of this study was to introduce a rapid palatal expander that requires only two anchor teeth (two-point RPEe) and to compare the expansion obtained with that from a Hyrax appliance. This study involved two groups of 25 children aged 7 to 15 years who were treated in a private orthodontist's office with either a Hyrax appliance or a two-point RPEe. Dental casts and occlusal radiographs were made before treatment and at least three months after stabilization of the appliance. Paired t-tests were performed to identify significant intragroup changes, and independent t-tests were performed to determine intergroup differences. The findings showed the two-point RPEe was as efficient as the Hyrax in obtaining dental expansion of the maxillary posterior teeth with less effect on the maxillary anterior and mandibular teeth. Therefore, the two-point RPEe may be useful in certain clinical situations. The purpose of this study was to compare skeletal and dental aspects of three different expansion methods in the mixed dentition period in sagittal, vertical, and transversal planes, treatment periods, complications, and relapse tendencies in early periods. Patients with unilateral or bilateral posterior crossbites in the mixed dentition were studied. They were divided into three groups of 10 patients in each group. The first group received treatment with removable plates for semirapid maxillary expansion; the second group with quad-helix appliances for slow maxillary expansion; and the third group with conventional fixed hyrax appliances for rapid maxillary expansion (RME). Lateral and posteroanterior cephalometric films, occlusal films, and dental casts were taken before and after expansion, and after retention with the same appliances. Cephalometric and dental cast analyses were made. Both skeletal and dental changes were observed after all three expansion methods. The correction of a unilateral first molar crossbite with a Goshgarian type of transpalatal arch was evaluated in 35 children from 6 years, 8 months to 15 years, 11 months old. Fifteen of the children were treated with an arch activated for expansion only and 20 children with an arch activated in a similar way but with the inclusion of buccal root torque of the anchorage tooth. With both types of activation, the arches worked in a statically determinate system, i.e., the tooth in crossbite was allowed to tip buccally. The movements of the first molars as a result of the treatment were monitored by measurements on dental casts and frontal cephalometric roentgenograms. In addition, the width of the midpalatal suture was measured on occlusal roentgenograms of the maxilla. In the children treated with an arch activated only for expansion, the molars on both sides of the dental arch moved buccally during the treatment. In the children treated by torque activation, on the other hand, there was a considerable buccal movement of the molar on the side of the crossbite without any significant buccal movement of the anchorage tooth. In individual cases, the molar on the noncrossbite side moved and tipped palatally and in some cases buccally but to a minor degree. With both types of activation, there was only a slight change in inclination of the transverse occlusal plane through the first molars; the plane opened up slightly toward the side of the crossbite. For both types of activation, there was a slight widening of the palatal suture during the treatment.(ABSTRACT TRUNCATED AT 250 WORDS) Various investigations have mentioned the use of a bonded maxillary expansion appliance. It was postulated that a full coverage of the occlusal surfaces by acrylic would remove interferences during the lateral displacement of the two maxillary bones and would lessen the resistance to maxillary expansion. The first objective of this study was to compare two appliances, a bonded and a banded Minne expander using a continuous force of two pounds, which would produce a slow maxillary expansion. The second objective was to evaluate the ratio between the skeletal and dental response to slow maxillary expansion, and to compare these results to those obtained with a rapid maxillary expansion procedure. Each experimental group consisted of 5 patients, aged between 8 and 12 years wearing the two different appliances. Prior to treatment they were implanted according to the Björk technique. The slow expansion period lasted 7 to 15 weeks followed by a retention period of 12 weeks. Post-retention observations followed 12 weeks after the end of retention. No significant difference was found between banded and bonded appliances in regard to dental and skeletal expansion and relapse. The amount of skeletal versus dental movements equalled results obtained with rapid maxillary expansion. The relapse tendency appeared lower than with rapid maxillary expansion.
The evidence from the trials reported by Thilander 1984 and Lindner 1989 suggests that removal of premature contacts of the baby teeth is effective in preventing a posterior crossbite from being perpetuated to the mixed dentition and adult teeth. When grinding alone is not effective, using an upper removable expansion plate to expand the top teeth will decrease the risk of a posterior crossbite from being perpetuated to the permanent dentition.The comparisons of treatments made in the trials reported by Mossaz-Joëlson 1989; Schneidman 1990; Ingervall 1995; Asanza 1997 and Sandikçioglu 1997 were inconclusive so recommendations for clinical practice can not be made based on the results of these trials. However, these trials were small and inadequately powered so further studies, with appropriate sample sizes, would be required to assess the relative effectiveness of these interventions.