To Örebro University

OBJECTIVES: To compare the effects of quad helix (QH) anchored on permanent molars versus rapid maxillary expansion (RME) anchored on deciduous teeth on palatal morphology in early mixed dentition patients.

TRIAL DESIGN: A two-arm randomized controlled trial, together with a non-randomized normal bite data for comparison.

METHODS: Seventy-one patients (mean age: QH=9.3years; RME=9.4years) with unilateral posterior crossbite were analysed. The QH group (n=36) and RME group (n=35) were evaluated at baseline (T0), post-retention (T2), and one-year post-treatment (T3). A third age- and sex-matched control group (n=22; mean age=9.1years) served as a normative reference. Evaluated outcomes were 3D palatal measurements, as well as treatment success rate and total treatment duration.

RESULTS: Both treatment groups showed significant increases in palatal surface area, projection plane area, and volume from T0 to T3. The RME group experienced a greater increase in palatal surface area (7.0%) compared to the QH group (4.2%) over the same period (P=0.045). Palatal volume increased notably more in the RME group during active treatment (T0-T2), with an 11.2% gain versus 6.8% in the QH group (P=0.046). By T3, palatal vault dimensions had normalized in both groups compared to the control group. The RME group completed treatment 97days earlier than the QH group.

CONCLUSIONS: Treatment with either QH or RME resulted in normalized palatal vaults compared to the control group. RME had a significantly shorter treatment time but achieved similar success in correcting posterior crossbite as QH. This trial was registered at ClinicalTrials.gov (ID NCT04458506) and Researchweb.org (project number 260581).

BACKGROUND: Unilateral posterior crossbite is a common malocclusion, and early treatment is recommended to enable normal growth. There are several possibilities regarding choice of appliances used for correcting this malocclusion; however, when treatment is financed by public funds the decision needs to be based not only on the effects but also on the effect in relation to the costs. OBJECTIVES: The aim was to perform a cost-effectiveness analysis comparing quad helix (QH) and rapid maxillary expanders (RME; hyrax-type) in children in the early mixed dentition.

MATERIAL AND METHODS: Seventy-two patients were randomized to treatment with either QH or RME, at two different centres. Data were collected from the patient's medical records regarding success rate, number of visits, total treatment time, emergency visits, and so forth, together with answers from patient questionnaires concerning absence from school and use of analgesics. A cost-effectiveness analysis with both an intention-to-treat (ITT) and a per-protocol approach was performed, as well as a deterministic sensitivity analysis.

RESULTS: The success rate, one year after the completion of the expansion, was equal between groups according to the ITT approach. From a healthcare perspective, the mean cost difference between RME and QH was €32.05 in favour of QH (P = 0.583; NS). From a societal perspective, the mean cost difference was €32.61 in favour of QH (P = 0.742; NS). The total appliance cost alone was higher in the RME group €202.67 resp. €155.58 in the QH group (P = 0.001). The probability of RME having a higher cost was 71% from a healthcare perspective and 62.7% from a societal perspective. The total treatment time was 97 days longer in the QH group. In the deterministic sensitivity analysis, when using a higher valuation of the children's educational loss, the QH becomes €58 more costly than the RME. There was a statistically significant difference in chair time and visits between centres (P < 0.001).

CONCLUSION: The difference in costs between RME and QH is not statistically significant, however, there is a slightly higher probability that RME is more expensive than QH with a mean cost of an additional €32 per patient from a healthcare perspective. Different work procedures at different centres indicate that logistics around the patient's treatment is a more important aspect than appliance used to decrease the number of visits and save chair time and thereby also costs.

Background: Posterior crossbite is one of the most common malocclusions in children and requires treatment to support normal growth. Various appliances can be used for correction. The overall aim of this thesis was to compare patients' experiences, treatment outcomes, and health impacts between two different appliances.

Materials and Methods: Two fixed appliances were compared in a randomized controlled trial (RCT). Slow expansion using a quad helix (QH) on the first permanent molars was compared to rapid palatal expansion (RME) with a Hyrax-type expander anchored on the deciduous second molar and canine in children with early mixed dentition. A total of 72 patients were randomized across two different centres.

Results: Both treatments were equally successful in achieving normal transverse relationships at follow-up. QH patients reported more initial pain, while RME patients experienced more speech difficulties during the first week. In the RME group, the midpalatal suture opened in a triangular fashion, widest anteriorly and inferiorly, whereas no suture opening was observed in the QH group. Side effects, such as buccal bone loss and fenestrations, were more common in the QH group. Palatal volume and areas were normalized in both treatment groups compared to a control group with normal occlusion. A health economic evaluation showed a minor societal cost differenceof €32, with the QH being less expensive, though this difference was not statistically significant. The treatment duration in the RME group was nearly 100 days shorter than in the QH group.

Conclusion: Both appliances were equally effective in normalizing the palate, but the RME had fewer side effects, a shorter treatment time, and no significant difference in overall costs.

Objectives: To assess skeletal and dental effects and evaluate possible side effects of maxillary expansion with two different appliances, directly after expansion and 1 year postexpansion.

Materials and Methods: Forty-two patients with unilateral posterior crossbite (mean 9.5 +/- 0.9 years) were randomized to either rapid maxillary expansion (RME) banded on the deciduous second molars and bonded to the primary canines or slow expansion with quad helix (QH) on the permanent first molars. Cone-beam computed tomography records were taken at baseline, directly after correction of the posterior crossbite and at follow-up 1 year after expansion.

Results: All patients were analyzed. RME opened the midpalatal suture more anteriorly and inferiorly (mean 4.1 mm) and less posteriorly and superiorly (mean 1.0 mm). No effect on midpalatal suture could be shown in the QH group after expansion, P < .001. Buccal bone width had significantly decreased (P < .001) in the QH group compared with the RME group. Buccal fenestrations and root resorption on the left first molar had a higher prevalence directly after expansion finished in the QH group (P = .0086, P = .013) but were not significant at 1-year follow-up (P = .11, P = .22).

Conclusions: Opening of the suture with RME was more anterior and inferior, and the QH did not open the midpalatal suture at all. More buccal bone loss and fenestrations were seen on the permanent first molar in patients treated with conventional QH than RME anchored to deciduous teeth.

BACKGROUND: Quad Helix (QH) is the appliance most preferred by orthodontists to correct unilateral posterior crossbite in the early mixed dentition while other orthodontists suggest rapid maxillary expansion (RME) on deciduous teeth in these patients.

OBJECTIVES: To evaluate and compare perceived pain intensity, discomfort, functional jaw impairment, and analgesic consumption during the first week of treatment with either RME or QH appliances.

TRIAL DESIGN: Two-arm parallel group, two-centre, randomized controlled trial.

MATERIAL AND METHODS: Seventy-two patients, mean age 9.5 (SD ±0.8) years, with unilateral posterior crossbite requiring maxillary expansion were randomly allocated to either the RME (22 boys, 14 girls) or QH (22 boys, 14 girls) group. Validated questionnaires were used to assess pain intensity, discomfort, jaw function impairment, and analgesic consumption, on the first, fourth, and seventh days after appliance insertion and activation.

BLINDING: Due to clinical limitations, only the outcome assessors were blinded to the groups to which the patients were allocated.

RESULTS: Seventy patients completed the questionnaires. Pain from the tongue and chafe from the appliance were significantly higher in the QH group on the first day of treatment (P = 0.003 and P = 0.000, respectively). On the fourth day, the chafe from the appliance was still significantly higher in the QH group (P = 0.007). Speech was affected in both groups on day 1; this impairment continued and was significantly higher in the RME group days 4 and 7. No significant difference in analgesic consumption was found between the groups at any time. The analgesic consumption was highest at day 1 of treatment.

HARMS: No harm was observed in any patient.

LIMITATIONS: Double blinding was not possible due to the clinical limitations.

CONCLUSION: During the initial 4 days of treatment, pain from the tongue and chafe from the appliance caused the most reported inconvenience in the patients in the QH group. A majority of reported visual analogue scale values were in the lower mid-range, suggesting low to moderate pain and discomfort in both groups.

CLINICAL TRIAL REGISTRATION: NCT04458506.

Purpose: The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks.

Materials and Methods: Twenty subjects (18 females and 2 males) with a mean age of 42.5 +/- 10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra-and inter-examiner reliability.

Results: No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P =0.783 and P =0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks.

Conclusion: The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra (R) M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.