Piezo1 Promotes Osteogenesis Through CaMKII Signalling in a Rat Maxillary Expansion Model.

OBJECTIVES: Rapid maxillary expansion (RME) is a widely used technique to treat maxillary transverse deficiency. Piezo1 is a cation channel that is activated by mechanical force and regulates bone formation. This study aims to elucidate the role of Piezo1 in bone remodelling during the RME process. MATERIALS AND METHODS: In this study, the periosteal-derived stem cells (PDSCs) were cultured and stretched by the Flexcell system. The effects of Piezo1 on osteogenesis were assessed via RNA sequencing, real-time quantitative PCR, and western blot analyses. Moreover, for in vivo analyses, the rat RME model was established. The function of Piezo1 in mid-palatal suture bone remodelling was evaluated using micro-CT, haematoxylin-eosin (HE) staining, and immunohistochemistry analyses. RESULTS: It was revealed that under tension force, the osteogenic factors (Runt-related transcription factor 2, Osterix, and Alkaline Phosphatase) and Ca2+/calmodulin -dependent protein kinase (CaMKII) were significantly enhanced in PDSCs over time. Furthermore, these were also upregulated in the RME model with the expansion of the mid-palatal suture. However, Piezo1 inhibition by Grammostola spatulata mechanotoxin 4 downregulated the levels of these factors in the RME model. CONCLUSIONS: This study indicated that Piezo1 is associated with the osteogenesis of PDSCs and bone remodelling in the RME process. CaMKII might also participate in this process.

Effect of rapid maxillary expansion on intracranial pressure.

Objective: The aim of this study was to evaluate the effects of rapid maxillary expansion on the optic nerve sheath diameter and to examine its possible effects on intracranial pressure. Design: 20 patients with bilateral crossbite were selected. Hyrax Expander was applied and activated twice daily until the overcorrection was achieved. The optic nerve sheath diameter (ONSD) was measured via ultrasonography before the first activation (T0), then repeated after 1 (T1) and 10 min (T2). At the end of the expansion, ONSD was measured (T3) again, then the screw was activated for the last time, and measurements were repeated after 1 (T4) and 10 min (T5). The Friedman test was performed to compare the changes, and The Wilcoxon Signed-Rank test was done to determine the significant intergroup changes (p < 0.05). Results: The ONSD increased significantly 1 min after the activations (T0-T1 and T3-T4) (P < 0.05). The ONSD values measured 10 min after the activations also increased significantly compared to the baseline values (T0-T2 and T3-T5) (P < 0.05). Conclusion: The activation of maxillary expansion appliances increased the optic nerve sheath diameter in adolescents. Therefore, orthodontists should be careful with patients at risk of intracranial hypertension.

The impact of different activation protocols of rapid maxillary expansion on external root resorption: a systematic review and meta-analysis.

This comprehensive meta-analysis investigated the effects of Rapid Maxillary Expansion (RME) on external root resorption, which is a prevalent orthodontic treatment intended to correct transverse maxillary deficiency and constricted dental arches. By conducting a systematic literature search across prominent electronic databases, including the Cochrane Library, EMBASE, LILACS, MEDLINE, PubMed, and Web of Science, the study compiled evidence until April 2023. A spectrum of search terms was utilized to capture diverse aspects of root resorption, RME, palatal expansion methods, and tooth erosion. Registered with INPLASY (202430057), the meta-analysis meticulously screened 11 studies that fulfilled stringent inclusion criteria. The quality of these studies was assessed using the Cochrane Bias Risk Assessment Tool for Randomized Controlled Trials (RCTs) and the Methodological Index for Non-Randomized Studies (MINORS) for other research designs. The collective analyses disclosed a substantial impact of RME on external root resorption, indicating that the treatment may induce pronounced root erosion. Subgroup analyses further elucidated distinct patterns in root resorption among various types of RME, underscoring the variability in treatment outcomes and the need for personalized care. Consequently, the meta-analysis unequivocally confirmed that external root resorption may be a concerning consequence of RME treatment, necessitating thorough monitoring and management strategies to mitigate potential adverse effects on dental health.

Mandibular response after rapid maxillary expansion in mixed dentition children with different vertical growth patterns: a retrospective study.

This study evaluated the mandibular development induced by rapid maxillary expansion (RME) therapy in mixed dentition patients with different vertical growth patterns through long-term observation. The research utilized a retrospective design that included two cohorts: a control group consisting of pediatric subjects with individualized malocclusions, and an experimental group received RME therapy. A total of 60 subjects were included; 37 in the RME group (17 males and 20 females) and 23 in the control group (13 males and 10 females). Based on mandibular plane angles, 19 pertinent cephalometric variables were quantified with Dolphin Imaging software, and participants were subclassified into high-angle and normal-angle subgroups. Changes in the groups during the observation period were statistically analyzed with a t-test. Compared to the control group, both sagittal parameters tended to decrease after treatment in the RME group (p < 0.05), and none of the vertical correlations were statistically different (p > 0.05). Within the normal-angle experimental subgroup, sagittal parameters markedly decreased when contrasted with their normal-angle control group (p < 0.05). Notably, a substantive decrease in overjet was solely observable in the sagittal dimension among the high-angle expansion subgroup when compared to the high-angle control subgroup (p < 0.05). In the vertical dimension, neither the normal-angle nor high-angle subgroups exhibited any statistically significant differences from their respective control cohorts (p > 0.05). Based on long-term observation, RME therapy promotes mandible sagittal growth of the mandible in subjects with normal-angle vertical growth patterns. A similar tendency was not observed in subjects with high-angle vertical growth patterns. In addition, the mandibular plane angle did not increase after RME in children with high-angles.

Three-dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni-ti leaf springs expander and rapid maxillary expander: A two-centre randomized controlled trial.

OBJECTIVE: The aim of this randomized controlled trial (RCT) was to evaluate the spontaneous distorotation of upper first permanent molars and the transverse dentoalveolar changes on digital casts in growing patients following maxillary expansion treatment using either the Leaf Expander® or the rapid maxillary expander (RME), both anchored to the deciduous second molar. TRIAL DESIGN AND SETTING: This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy. PARTICIPANTS: Inclusion criteria included maxillary transverse deficiency, prepubertal development stage (cervical vertebra maturation stage [CVMS] 1-2) and early mixed dentition with fully erupted upper first permanent molars. Exclusion criteria were systemic diseases or syndromes, CVMS 3-6, agenesis of upper second premolars, unavailability of the second deciduous molar for anchorage and Class III malocclusion. RANDOMIZATION: Patients were randomly assigned to the Leaf Expander® or RME group using a computer-generated randomization list created by a central randomization centre. Randomization was conducted immediately before the start of treatment. INTERVENTION: The intervention involved treatment with either the Leaf Expander® or the RME. Both devices were anchored to the second deciduous molars. Following randomization, patients were further categorized based on the presence of no crossbite, unilateral crossbite or bilateral crossbite. MAIN OUTCOME MEASURE: The primary outcome measure was the distorotation of the upper first molar (U6). Secondary outcomes included measurements of interdental linear dimensions, specifically upper inter-canine width (53-63), upper inter-molar width (MV16-MV26) and upper inter-deciduous second molar width (55-65). BLINDING: The examiner analysing the digital casts was blinded to the treatment groups to prevent detection bias and ensure objective assessment. However, due to the nature of the intervention, blinding was not feasible for the patients and clinicians involved in administering the treatment. RESULTS: A total of 150 patients were enrolled and randomly assigned to two groups: 75 to the Leaf Expander® group and 75 to the RME group. Recruitment started in November 2021 and was completed in November 2022. At the time of analysis, the trial was complete with no ongoing follow-ups. ANOVA tests revealed no significant differences between the three subgroups (no-cross, unilateral-cross and bilateral-cross) within both the Leaf Expander® and RME groups at T0. The Leaf Expander® demonstrated significantly greater distorotation in the unilateral crossbite subgroup compared to the RME (p = .014). In terms of total molar distorotation, the Leaf Expander® appliance showed a significantly greater effect (12.66°) compared with conventional RME (7.83°). Linear regression analysis demonstrated a significant correlation between the extent of expansion and the degree of molar rotation. CONCLUSIONS: Maxillary expansion resulted in significant spontaneous molar distorotation when the appliance was bonded to the second deciduous molars. The Leaf Expander® exhibited significantly greater molar distorotation compared with conventional RME. The degree of molar distorotation was correlated with the extent of expansion obtained on the second deciduous molar. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov (ID: NCT05135962).

Evaluation of the Effects of Orthopedic Treatment on the Dentofacial Structure and Upper Airway of Subjects with Skeletal Class III Malocclusion.

Objective: The present study aimed to evaluate the effect of rapid maxillary expansion (RME) and face mask treatment on the upper airway in patients with maxillary retrusion in two dimensions using digital cephalograms and volumetric evaluation using acoustic rhinometric measurements. Methods: A total of 22 individuals with a concave profile and skeletal and dental Class III malocclusion during growth and development with a mean age of 9.9±1.38 years were included in the study. A bonded RME appliance and a petit face mask were adapted for the patients. Before treatment (T0) and after maxillary protraction (T1), lateral cephalometric films and acoustic rhinometric recordings were obtained. The dependent sample t-test was used for statistical evaluation. Results: Cephalometric analysis revealed forward movement of the maxilla and backward downward rotation of the mandible. A significant increase was observed in the nasopharyngeal and oropharyngeal regions of the upper airway. Three-dimensional evaluation of the upper airway by acoustic rhinometry revealed only an increase in the volumes of the left nasal cavity after decongestant administration. A statistically significant increase in acoustic rhinometric measurements in nasal valves. When the correlation of the cephalometric findings of the nasopharyngeal region with the acoustic rhinometry findings was examined, no statistically significant relationship was found. Conclusion: As a result of this study, we observed an increase in the cephalometric measurements of the nasopharyngeal and oropharyngeal areas. A significant increase was observed in the minimal cross-sectional area measured by acoustic rhinometry.

Bibliometric Analysis of Maxillary Expansion Publications Trends.

Objective: Maxillary expansion is a common treatment in clinical orthodontics and can be performed in a wide age range using different methods. This bibliometric analysis aims to provide an overview of research on maxillary expansion. Methods: A literature search was performed in the Web of Science database, and publications related to maxillary expansion between 1970 and 2023 were included. Data, including titles, abstracts, keywords, countries, regions, and references, were exported and analyzed within the scope of the bibliometric indicators. Results: The study was conducted on 2633 publications. Between 1970 and 2023, research on maxillary expansion showed a general upward trend in the number of publications. From the analyzed publications, we observed that rapid maxillary expansion (RME) was the most common type of maxillary expansion, accounting for 78% of all publications. Most publications originated from the United States (24.3%), and these articles were also the most cited (17180). Lorenzo Franchi contributed the most publications (85, 3.2%) and was cited 2830 times for maxillary expansion. The highest number of publications was from the University of Sao Paolo (119), and the most cited institution was the University of Florence (3287). Conclusion: The bibliometric indicators showed a rapid increase in the number of published works on the topic of maxillary expansion, particularly in recent years. Advances in patient evaluation (3D imaging, modeling) and application methods (mini-screws, clear aligners) appear to have helped to maintain the popularity of maxillary expansion. We also observed that maxillary expansion is associated with several other specialties in addition to dentistry.

Evaluation of Treatment Protocols in Surgically Assisted Rapid Maxillary Expansion by Finite Element Analysis.

Background and Objectives: Transverse maxillary deficiency is an important maxillary anomaly that is very common in society and remains current in orthodontics. The maxillary expansion has been used in treatment for a long time. While maxillary expansion can be performed with rapid maxillary expansion in young adults, it is performed with surgically assisted rapid maxillary expansion (SARME) in individuals who have reached skeletal maturity. No consensus has been reached on the most successful surgical technique or the ideal appliance for treating transverse maxillary deficiency. Accordingly, we aimed to evaluate various surgical techniques and orthodontic appliances for treating transverse maxillary deficiency using the finite element method (FEM) to identify the treatment protocol that minimizes stress on the maxillary bone and teeth. Materials and Methods: On the virtual models obtained from the cone beam computed tomography of a patient, two different incisions (the pterygomaxillary junction is separated and not separated) were made and combined using three different orthodontic appliances (tooth, bone, and hybrid assisted). Then, stresses over the maxillary bone and maxillary teeth were calculated by FEM. Results: Our results showed that when the pterygomaxillary plates were separated, fewer stresses were observed on the bone and teeth. Although hybrid-supported appliances created less stress on the teeth than tooth-supported appliances and no difference was found between bone-supported appliances, it was found that hybrid-supported appliances created less stress on the bone than the other appliances. Conclusions: The separation of the pterygomaxillary junction in the SARME operation and the use of a bone-supported or hybrid-supported appliance would place less stress on the bone and teeth.

Evaluation of Orthodontic Treatment Modalities for Obstructive Sleep Apnoea: A Systematic Review.

Obstructive sleep apnoea (OSA) poses a significant health burden globally, necessitating effective intervention strategies to mitigate its adverse consequences. Orthodontic treatment modalities offer promising avenues for addressing OSA by targeting the underlying anatomical abnormalities and restoring unobstructed airflow during sleep. This systematic search was conducted across multiple electronic databases using predefined search terms and inclusion criteria. Studies eligible for inclusion encompassed a range of study designs, including randomized controlled trials, prospective and retrospective studies, clinical trials, and observational studies. Outcome measures included changes in apnoea-hypopnoea index (AHI), oxygen saturation levels, polysomnographic variables, skeletal/cephalometric changes, nasal parameters, upper airway morphology, and clinical symptoms. Initially, 756 records were identified through database searches, with 21 studies meeting the inclusion criteria after meticulous screening and selection. Orthodontic interventions, including rapid maxillary expansion (RME), personalized oral appliances, mandibular positioning devices, and comprehensive orthodontic protocols, demonstrated significant promise in ameliorating OSA symptoms among paediatric populations. Improvements in AHI, nasal resistance, sleep parameters, and upper airway dimensions were consistently observed across various studies, highlighting the potential of orthodontic treatments in mitigating OSA severity. This systematic review underscores the efficacy of orthodontic treatment modalities in addressing OSA among paediatric populations. Despite certain limitations in study design and outcome measures, the review emphasizes the need for further well-designed randomized controlled trials to validate and optimize these interventions for paediatric patients with OSA. Enhanced understanding and implementation of orthodontic treatments hold promise for alleviating the burden of OSA on global health and well-being.

Severe Maxillary Protrusion Treated with Surgically Assisted Rapid Maxillary Expansion.

In this case, surgically assisted rapid maxillary expansion (SARME) was successfully adopted to treat a skeletal maxillary protrusion with large overjet and severe crowding. The female patient, aged 25 years and 11 months, was diagnosed with skeletal maxillary protrusion with severe crowding and excessive overjet associated with labially inclined maxillary central incisors. After achieving sufficient space for surgical incision between bilateral maxillary central incisors, the SARME was performed. A total of 8.0 mm lateral expansion of the maxilla was completed. At 48 days after surgery, the Hyrax appliance was replaced with an Anchor-Lock system used as an external surgical stent and skeletal anchorage for maxillary group distalization, and the distal movement of the maxillary molars was initiated without waiting for bone healing of the separated midpalatal suture by SARME. Twenty-five months' treatment, including surgical preparation, achieved an acceptable and stable occlusion with adequate interincisal relationship. The occlusion was much more stable with a little relapse through more than 4 years' retention period. In conclusion, SARME followed by the Anchor-Lock system might lead to favorable occlusal outcome in the long term without any relapses.