Maxillary Transverse Deficit: A Retrospective Study of Two Biologically Oriented Devices through a Digital Workflow

The aim of this retrospective study was to compare the efficiency of two biologically oriented devices in achieving maxillary expansion: Rapid Palatal Expander (RPE) and Nitanium Palatal Expander-2 (NPE-2). Thirty-six subjects, divided in two equal groups, were included in this study. Maxillary dental arches were scanned using Trios 3 shape®, in order to perform a digital analysis of 3D models. The models were analyzed using Autodesk Fusion 360® and Meshmixer®. All data obtained from analysis of pre-treatment and post-treatment models were processed using Prism® software. The anterior arch width, the posterior arch width, the palate height, and palatal surface were measured to evaluate differences between the devices. A D’Agostino–Pearson normality test was done to check the data. A non-parametric t-test was used to compare the anterior and posterior arch width between the two groups, while a parametric t-test was used to compare the palatal height measurements between the two groups. The p-value was calculated. The limit value fixed was 0.05. Palatal width and surface showed a significant increase in both groups, but no significant changes in palatal height were found. The data processed showed that there were no significant differences between the devices (ΔREP−ΔNPE) in variation of anterior arch width, there were no significant differences in variation of posterior arch width and there were no significant differences in variation of palatal height. The comparison between the two groups showed that both methods were equally effective in correcting transverse defect.

Skeletal and Alveolar Changes in Conventional Rapid Palatal Expansion (RPE) and Miniscrew-assisted RPE(MARPE): a Prospective Randomized Clinical Trial Using Low-dose CBCT

Background: This prospective randomized clinical trial aimed to evaluate the short-term effects of rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE) on skeletal, dentoalveolar, and periodontal structures in adolescent and young adult patients. Methods: Thirty-six patients (12 men and 24 women) requiring maxillary expansion were randomly allocated to RPE (n=17) or MARPE (n=19) groups. Upon identical (35 turns) amount of expansion, low-dose cone-beam computed tomography images were taken before treatment (T0), immediately after expansion (T1), and after a 3-month consolidation period (T2). Skeletal, dentoalveolar, and periodontal measurements were performed at each time point. Results: A greater increase in nasal width in the molar region (M-NW) and greater palatine foramen (GPF) was observed immediately after expansion (T1-T0) and consolidation periods (T2-T0) in MARPE group (P<0.05). MARPE and RPE groups showed similar dentoalveolar changes except for the maxillary width (PM-MW, M-MW) (P<0.05). Through the expansion and consolidation periods (T2-T0), lesser buccal displacement of the anchor teeth was observed in the MARPE group (PM-BBPT, PM-PBPT, M-BBPT [mesial and distal roots], and M-PBPT) (P<0.05).Conclusions: Both RPE and MARPE groups exhibited significant triangular basal bone expansion and skeletal relapse during consolidation. Under identical amounts of expansion, the MARPE group showed lower decrease in the skeletal, dentoalveolar and periodontal variables after consolidation. The reinforcement of RPE with miniscrews contributes to the maintenance of the basal bone during consolidation period. This evidence can help clinicians decide the appliance design for maxillary expansion, while preventing periodontal side effects, such as buccal bone dehiscence Trial registration: WHO Institutional Clinical Trials Registry Platform (IRB No. KCT0006871 / Registration Date 27/12/2021)

Modified Hyrax for Microimplant-Assisted Rapid Palatal Expansion

Temporary anchorage device-assisted rapid maxillary expansion has widened the horizon to treat adults having maxillary transverse deficiency without any surgical procedure. Three-dimensional custom modifications have also been developed, but they can be expensive. A modification of Hyrax screw with the use of lingual sheaths is suggested for microimplant-assisted rapid palatal expansion, which can be an easy to fabricate in-office and economical option.

Parathyroid hormone promotes maxillary expansion and reduces relapse in the repeated activation maxillary expansion rat model by regulating Wnt/β-catenin pathway

Background Constricted maxillary bone is a common skeletal deformity, which may lead to crowding and posterior crossbite. Mid-palatal suture expansion is often used to increase the maxillary width, but its skeletal effects are limited and tend to relapse, even with prolonged retention. We hypothesized that parathyroid hormone (PTH) may reduce the relapse of maxillary expansion. Methods We established a novel rat maxillary expansion model using palatal tubes with an insertable “W”-shaped spring which can be repeatedly activated. A total of 32 male healthy Wistar rats were randomly divided into six groups: the control group, the PTH group, the expansion group, the expansion + PTH group, the expansion + relapse group and the expansion + PTH + relapse group. All animals in the first 4 groups were killed after 10 days and the 2 relapse groups were killed after 15 days. The maxillary arch widths and histological staining were used to assess the expansion and relapse effects. The immunohistochemical staining, micro-CT, RT-qPCR and Western blot were used to evaluate the bone remodeling during expansion. Results The suture width was increased by the expansion device, and the repeated activation maxillary expansion rat model showed better expansion effects than the conventional model. PTH significantly promoted the expansion width and reduced the relapse ratio. Meanwhile, in the expansion + PTH group, histological and immunohistochemical staining showed that osteoblasts, osteoclasts, new cartilage and osteoid were significantly increased, micro-CT showed increased bone mass, and PCR and Western blot results confirmed up-regulation of RANKL, β-catenin, type II collagen and OCN. Conclusion The novel repeated activation maxillary expansion rat model has better effects than the conventional model. PTH enhances the maxillary expansion and reduces its relapse by regulating Wnt/β-catenin and RANKL pathways. PTH administration may serve as an adjunctive therapy in addition to mechanical expansion for treatment of maxillary constriction.

The effect of adenotonsillectomy and rapid maxillary expansion on the upper airway in pediatric obstructive sleep apnea: a randomized crossover-controlled trial

Study Objectives We aimed to determine the effects of adenotonsillectomy (AT) and rapid maxillary expansion (RME) on the apnea-hypopnea index (AHI) and compare volumetric changes in the upper airway (UA) arising from AT and RME. Methods Thirty-nine children who presented with maxillary constriction and grade III/IV tonsillar hypertrophy were randomized into two groups. One group underwent AT as the first treatment, and the other group underwent RME. Polysomnography (PSG) and cone-beam computed tomography (CBCT) were conducted before (T0) and 6 months after the first treatment (T1). In a crossover design, individuals with AHI&gt;1 received the second treatment. Six months later, they underwent PSG and CBCT (T2). The influence of age, sex, tonsil and adenoid hypertrophy, initial AHI severity, initial volume of the UA, first treatment, and maxillary expansion amount was evaluated using linear regression analysis. Intra- and inter-group comparisons for AHI and inter-group comparisons of volumetric changes in each region of the UA were performed using a paired t-test and Wilcoxon test. Results The initial AHI severity and therapeutic sequence in which AT was the first treatment explained for 95.6% of AHI improvement. AT caused significant improvements in the AHI and volumetric increases in the buccopharynx and total UA areas compared to RME. Conclusions The initial AHI severity and AT as the first treatment accounted for most of the AHI improvement. Most reductions in AHI were due to AT, which promoted more volumetric increases in UA areas than RME. RME may have a marginal effect on pediatric obstructive sleep apnea.