Effects of rapid maxillary expansion on upper airway parameters in OSA children with maxillary restriction: A CBCT study.

BACKGROUND: Rapid maxillary expansion (RME) has been proposed as an effective treatment for pediatric obstructive sleep apnea (OSA) and maxillary restriction in children. This study aimed to evaluate the effect of RME appliances on the nasomaxillary complex dimensions in children with OSA and maxillary constriction. METHODS: This prospective longitudinal study included 34 children aged 8-12 years with maxillary restriction and OSA confirmed by polysomnography who had completed RME therapy. The nasomaxillary complex is segmented into the nasal cavity, maxillary sinuses, and nasopharynx. The effect of RME on nasomaxillary complex dimensions was assessed pre and posttreatment using cone-beam computed tomography, analysis, while a second standard overnight polysomnography (PSG) was performed to assess changes in respiratory parameters. RESULTS: Significant improvements were observed, including inferior maxillary dislocation (S-S1 distance and N-ANS), increased anterior and posterior facial height, and a 5.43 events/h reduction in Apnea-Hypopnea Index (p < .001). The nasal cavity volume increased by 2439 (±584) mm3 (p < .001), nasopharynx size increased by 883 (±479) mm3 (p = .008), mid cross-sectional area increased by 31.74 (±14.50) mm2 (p < .001), and the distance between the right and left maxillary sinuses increased by 8.37 (±3.67) mm (p < .001) all exhibited positive changes, with some insignificant variations in volume change (p = .254). CONCLUSION: RME treatment was found to be effective in improving nasal cavity and nasopharyngeal dimensions, leading to improved respiratory parameters in children with OSA and maxillary constriction. While these results are promising, considerations about the potential long-term benefits of RME on future growth are important. The study provides valuable insights into the efficacy of RME as a treatment option for this pediatric population.

The effects of pterygomaxillary disjunction in surgically assisted rapid maxillary expansion: A systematic review and meta-analysis.

OBJECTIVE: This study aims to assess the expansive effects of pterygomaxillary disjunction (PMD) in surgically assisted rapid maxillary expansion (SARME) surgery using a meta-analysis approach. MATERIALS AND METHODS: The study conducted a comprehensive literature search across five databases: PubMed, Scopus, Medline, Embase, and Cochrane, adhering to the PRISMA 2020 guidelines. Dental alterations were assessed using either cone-beam computed tomography (CBCT) or dental casts, while skeletal changes were exclusively measured from CBCT scans. We analysed the dentoskeletal changes between PMD +/- groups and conducted a within-group comparison. The primary focus of the results was on the mean differences observed in pre- and post-operative measurements. RESULTS: Dental expansion was larger in the PMD+ group but not statistically significant. Skeletal expansion showed a significantly larger expansion in the posterior region in the PMD+ group (P = .033). Without PMD, anterior palatal expansion was significantly larger (P = .03), and the buccal tipping of posterior teeth was also significantly larger (P = .011) to achieve acceptable dental expansion outcomes. CONCLUSIONS: Both PMD +/- groups of SARME surgery can achieve satisfactory dental expansion outcomes. However, bone expansion and tooth inclination are also important factors that influence orthodontic treatment and post-expansion stability. By reducing the bony resistance with PMD, larger posterior palatal expansion and more parallel bony expansion are observed. In contrast, without PMD, there is smaller palatal expansion and greater tooth inclination in the posterior region. This could potentially lead to compromised periodontal conditions following expansion.

Ultrasonic mapping of midpalatal suture - An ex-vivo study.

OBJECTIVE: Rapid maxillary expansion is a common orthodontic procedure to correct maxillary constriction. Assessing the midpalatal suture (MPS) expansion plays a crucial role in treatment planning to determine its effectiveness. The objectives of this preliminary investigation are to demonstrate a proof of concept that the palatal bone underlying the rugae can be clearly imaged by ultrasound (US) and the reconstructed axial view of the US image accurately maps the MPS patency. METHODS: An ex-vivo US scanning was conducted on the upper jawbones of two piglet's carcasses before and after the creation of bone defects, which simulated the suture opening. The planar images were processed to enhance bone intensity distribution before being orderly stacked to fuse into a volume. Graph-cut segmentation was applied to delineate the palatal bone to generate a bone volume. The accuracy of the reconstructed bone volume and the suture opening was validated by the micro-computed tomography (µCT) data used as the ground truth and compared with cone beam computed tomography (CBCT) data as the clinical standard. Also included in the comparison is the rugae thickness. Correlation and Bland-Altman plots were used to test the agreement between the two methods: US versus µCT/CBCT. RESULTS: The reconstruction of the US palatal bone volumes was accurate based on surface topography comparison with a mean error of 0.19 mm for pre-defect and 0.15 mm and 0.09 mm for post-defect models of the two samples, respectively when compared with µCT volumes. A strong correlation (R2 ≥ 0.99) in measuring MPS expansion was found between US and µCT/CBCT with MADs of less than 0.05 mm, 0.11 mm and 0.23 mm for US, µCT and CBCT, respectively. CONCLUSIONS: It was possible to axially image the MPS opening and rugae thickness accurately using high-frequency ultrasound. CLINICAL SIGNIFICANCE: This study introduces an ionizing radiation-free, low-cost, and portable technique to accurately image a difficult part of oral cavity anatomy. The advantages of conceivable visualization could promise a successful clinical examination of MPS to support the predictable treatment outcome of maxillary transverse deficiency.

Transient bacteremia following the removal of four different types of rapid palatal expanders.

PURPOSE: General health related recommendations for prophylactic measures in connection with orthodontic treatments are limited due to the lack of evidence-based data. This study aimed to investigate the development of transient bacteremia following the removal of four types of rapid palatal expanders (RPE). METHODS: Seventy-five individuals aged 10-18 years undergoing rapid palatal expansion with four types of RPE were categorized according to the type of RPE used in their treatment: banded tooth-borne (group A (1), n = 17), banded tooth- and tissue-borne (group A (2), n = 17), bonded tooth-borne (group B (1), n = 18), and bonded tooth- and tissue-borne (group B (2), n = 23). Gingival inflammation was assessed using the gingival index one day before RPE removal. Furthermore, samples of blood (5 ml each) were collected before and 3 min after RPE removal. The groups were statistically evaluated for comparability with respect to sex, age, or wear time of the RPE and to the gingival index. In addition, the prevalence of bacteremia in the different groups was evaluated and statistically compared. RESULTS: No significant difference was found among the groups (p > 0.05) for sex, age, and RPE wear time. Mean gingival index was higher in group B (2) than in group A (1) (p < 0.05). The prevalence of bacteremia did not differ significantly between groups. Streptococcus species were identified in all bacteremia cases. The bacteremia prevalence of the groups was as follows: group A (1), 11.8%; group A (2), 23.5%; group B (1), 16.7%; and group B (2), 30.4%. CONCLUSION: This investigation demonstrated that removal of a RPE could cause bacteremia, but the RPE design did not affect the prevalence of bacteremia. The results of this study support the necessity of prophylaxis measures before RPE removal in indicated patients.

Can different osteotomies have an influence on surgically assisted rapid maxillary expansion? A systematic review.

The purpose of this study was to systematically review the randomized and non-randomized clinical trials (RCT; nRCT) concerning the different available osteotomies for surgically assisted rapid maxillary expansion (SARME): pterygomaxillary disjunction (SARME + PD vs SARME-PD) and segmental Le Fort I osteotomy (2-piece vs 3-piece). Outcomes focused on skeletal, dental, upper airway changes, complications, and relapse. Two authors investigated five databases (PubMed, Cochrane Library, Google Scholar, Scopus, Web of Science) until August 2023. The Cochrane Collaboration Tool and the Newcastle-Ottawa scale were used for the quality assessment of the included RCTs and nRCTs, respectively. A total of 554 articles were retrieved and after duplicates removing and full-text reading, 40 studies were included. Two RCTs showed a low risk of bias, one an unclear risk and one a high risk. Among the non-RCTs, 15 studies showed a good quality, while 21 exhibited a fair quality score. SARME + PD resulted in more homogeneous posterior bone expansion, with minimal dental effects. No difference between 2-piece and 3-piece in asymmetric expansion was observed, although 3SO showed 1-2 mm of more transverse increase. The oropharynx minimum cross-sectional area, the nasopharynx and the oropharynx volume were greater in SARME + PD. Both dental and bone relapse can occur but no differences between the groups were observed. All osteotomies guaranteed a correction of transverse maxillary deficiency. Lower side effects were described in SARME + PD. Two-piece and 3-piece segmental Le Fort I osteotomies did not show any differences in the symmetry and amount of expansion.

The effect of vertical skeletal proportions, skeletal maturation, and age on midpalatal suture maturation: a CBCT-based study.

BACKGROUND: Midpalatal suture (MPS) maturation may be influenced by a range of parameters including age, gender, and vertical skeletal pattern. We therefore aimed to evaluate the effect of Frankfurt-mandibular angle (FMA), skeletal maturation, and age on the timing of MPS maturation. METHODS: In this cross-sectional study, cone-beam computed tomography (CBCT) and lateral cephalograms were used to assess the MPS and cervical vertebral maturation (CVM) stage. A proportional odds logistic regression model was used to assess associations between age adjusted for gender and MPS maturation, and a regression analysis was performed to analyze the effect of vertical pattern on these associations. RESULTS: A total of 201 patients (84 male and 117 female) with a mean age of 13.48 (SD 1.94) were included. With increasing age, the odds of belonging to a higher maturation stage increased (OR: 2.14; 95% CI 1.789; 2.567; P < 0.001); however, no association between FMA and MPS maturation was observed (OR: 1.01; 95% CI 0.964; 1.051; P = 0.76). A strong correlation between MPS maturation and CVM stage was not reported. Males had a higher probability of belonging to a lower MPS maturation stage (OR: 0.24; 95% CI 0.136; 0.415; P < 0.001). CONCLUSIONS: Based on this cross-sectional analysis, midpalatal sutural maturation classification is associated with chronological age and occurs later in males. Neither CVM staging nor variation in vertical skeletal proportions were useful predictors of midpalatal maturation stage.

Fat mass and obesity-associated protein (FTO) affects midpalatal suture bone remodeling during rapid maxillary expansion.

BACKGROUND: The fat mass and obesity-associated protein (FTO) is an RNA demethylase that contributes to several physiological processes. Nonetheless, the impact of FTO on bone remodeling in the midpalatal suture while undergoing rapid maxillary expansion (RME) remains unclear. METHODS: First, to explore the expression of FTO in the midpalatal suture during RME, six rats were randomly divided into two groups: Expansion group and Sham group (springs without being activated). Then, suture mesenchymal stem cells (SuSCs) were isolated as in vitro model. The expression of FTO was knocked down by small interfering RNA to study the effect of FTO on the osteogenic differentiation of SuSCs. Finally, to evaluate the function of FTO in the process of bone remodeling in the midpalatal suture, ten rats were randomly divided into two groups: FB23-2 group (10 µM, a small molecule inhibitor of FTO) and DMSO group (control). RESULTS: Increased arch width and higher expression of OCN and FTO in the midpalatal area were observed in expansion group (P < .05). In the in vitro model, the mRNA expression levels of Runx2, Bmp2, Col1a1, Spp1, and Tnfrsf11b were decreased (P < .05) upon knocking down FTO. Additionally, the protein levels of RUNX2 and OPN were also decreased (P < 0.05). Adding FB23-2, a small-molecule inhibitor targeting FTO, to the medium of SuSCs caused a decrease in the mRNA expression levels of Runx2, Bmp2, Col1a1, Spp1, and Tnfrsf11b (P < 0.05). There was a statistically significant difference in evaluating the expression of OCN and OPN on the palatal suture between the FB23-2 and DMSO groups (P < .05). LIMITATION: The molecular mechanisms by which FTO regulates SuSCs osteogenesis remain to be elucidated. The FTO conditional knock out mouse model can be established to further elucidate the role of FTO during RME. CONCLUSION: FTO contributes to the osteogenic differentiation of SuSCs and plays a promoting role in midpalatal suture bone remodeling during the RME.

Short- and Long-Term Effects of Maxillary Expander with Tongue Crib in Growing Open-Bite and Skeletal Class II Patients: A Retrospective Study.

The purpose of this study was to evaluate short- and long-term changes in growing patients with Class II malocclusion and open bite after rapid maxillary expansion (RME). A retrospective cohort study was conducted with 16 growing patients with open-bite malocclusion enrolled in a group treated with a rapid maxillary expander (RME) with a crib (TG), and 16 untreated patients with similar malocclusion in the control group (CG). Cephalograms were recorded before starting the treatment (T0), at the end of the latency phase (T1), and before the fixed therapy (T2) in order to analyze skeletal and dental changes in vertical, transversal, and sagittal relationships. Statistical analysis was performed with α = 0.05 as level of significance. At the end of the active expansion (T1), all subjects in the TG showed a corrected overbite with a statistically significant difference compared to the CG (p > 0.05). A significant decrease in jaw divergence was found in the TG compared to the CG (p < 0.05). At T2, all treated patients maintained a correct overbite. Statistical analysis revealed a significant decrease in maxillary, mandibular, and intermaxillary divergence in the TG compared to the CG (p < 0.05). This protocol could be effective in growing open-bite patients, showing a long-term decrease in facial divergence. The fixed crib allowed to normalize myofunctional activity.

Effects of different distractor positions on the formation of expansion, stress and displacement patterns in surgically assisted rapid maxillary expansion without pterygomaxillary disjunction: a finite element analysis study.

Skeletal orthopedic expansion of maxilla is accepted as a reliable method for the treatment of transverse maxillar deficiency in growing patients. The aim of the study was to evaluate the effects of different palatal distractor positions on the expansion, stress and displacement patterns of the structures of craniofacial complex in surgical assisted rapid maxillary expansion without pterygomaxillary disjunction (PTMD) with the help of finite element analysis(FEA). Four facial skeleton models with different distractor positions (first premolar, second premolar, first molar, second molar regions) were created. In all finite element models median and lateral osteotomies were performed, without PTMD. Stress distribution was evaluated after 5 mm activation of the transpalatal distraction in all models using the nonlinear solution method in FEA. Unilateral displacement(mm) and stress distribution(MPa) were measured in three directions (x, y, and z axes) of craniofacial and maxillofacial structures in the symmetrical finite element models. In all models, the unilateral transverse displacements of the anterior teeth were greater than those of the posterior teeth, and the greatest displacement was at the central incisor level. The greatest displacement values at the central incisor level, at the anterior nasal spine(ANS) and at the posterior nasal spine(PNS) levels was measured in Model-IV, III, II and I, respectively. Mean elemental stress(von Mises stress) in the medial pterygoid plate, screw and lateral pterygoid plate regions from highest to lowest was measured in Model-IV, III, II and I, respectively. The maxilla performed outward rotation and tipping movement in all models during the expansion period. Among the distractor positions, the second molar region was found to be the most advantageous one in terms of expansion pattern. Considering the patient's anatomy and clinical conditions, placing the palatal distractor as posteriorly as possible will result in more effective maxillary expansion.

Effects of rapid maxillary expansion on sleep disturbance scale for children: A longitudinal CASE-series study.

OBJECTIVE: To evaluate the effects of rapid maxillary expansion (RME) on Sleep Disturbance Scale for Children (SDSC) with maxillary atresia. MATERIALS AND METHODS: The sample consisted of 27 paediatric patients evaluated through a Brazilian version of the SDSC, answered by their guardians at the following experimental time points: T0 (before installing the Hyrax expander), T1 (on the day of expander stabilization), T2 (3 months after expander stabilization), T3 (immediately after expander removal, following 6 months of retention), and T4 (3 months post-retention). Multilevel Poisson analysis adjusted for repeated measures was performed to compare outcomes across the assessment time points. RESULTS: The mean age of patients was 9.1 years (SD = 1.46). The total SDSC scores decreased and were statistically significant from T2 onwards (P < .01), with a decrease of 24% at T4 compared with T1 (IRR 0.76; 95% CI 0.69-0.84). The mean scores at T4 were already lower than the cutoff point for risk of sleep disorders. Regarding the specific domains, there was a significant reduction in sleep breathing disorders, sleep-wake transition disorders, and disorders of excessive somnolence as of T2 (P < .01), T3 (P < .05) and T4 (P < .05), respectively. CONCLUSION: RME in children with maxillary atresia had a positive effect on the reduction of total SDSC scores after 3 months of expander stabilization, sustained over 6 and 9 months and significant reduction in sleep breathing disorders domain, sleep-wake transition disorders domain, and disorders of excessive somnolence domain over time points.

Can rapid maxillary expansion affect speech sound production in growing patients? A systematic review.

Rapid maxillary expansion (RME) may change speech sound parameters due to the enlargement of oral and nasal cavities. This study aimed to systematically review the current evidence on speech changes as a side effect of RME. An electronic search was conducted in nine databases, and two of them accessed the 'grey literature'. The eligibility criteria included clinical studies assessing orthodontic patients with maxillary transverse deficiency and the relationship with speech alterations without restricting publication year or language. Only interventional studies were included. The JBI Critical Appraisal Tool assessed the risk of bias. The initial search provided 4853 studies. Seven articles (n = 200 patients) met the inclusion criteria and were analysed. The primary source of bias was the absence of a control group in four studies. RME altered speech production by changing vowel fundamental frequency and fricative phoneme formant frequency. Shimmer and jitter rates changed in one and two studies, respectively. Two studies presented deterioration during orthodontic treatment, but speech improved after appliance removal. Despite the limited evidence, RME affects speech during and after treatment.

Age-related changes in the midpalatal suture: Comparison between CBCT staging and bone micromorphology.

The age-related maturation of the human midpalatal suture is challenging to predict, but critical for successful non-surgical rapid maxillary expansion (RME). While cone-beam computed tomography (CBCT) can be used to categorize the suture into stages, it remains unclear how well the stages predict the actual micromorphology of the palate. To address this clinically relevant question, we used CBCT together with three-dimensional micro-computed tomography (µCT) analysis on 24 human palate specimens from individuals aged 14-34 years. We first classified the specimens into stages (A-E) using CBCT images and then correlated the results with our comprehensive µCT analysis. Our analysis focused on several factors, including bone volume fraction (BV/TV), sutural width, volume, interdigitation, ossification, and their associations with age, CBCT stage, and sex. Our µCT analysis revealed a decrease in sutural width and volume after the age of 20 years, accompanied by sutural closure beginning in the palatal segment. The overall rate of ossification remained low but increased after the age of 20 years. No significant differences were found between males and females. Importantly, we also found no correlation between individual age and CBCT stages. Furthermore, there was no association between CBCT stages and patalal suture volume, ossification and interdigitation. Taken together, our findings cast doubt on the reliability of CBCT stage as a means of predicting skeletal maturity of the palatal suture, as it appears to lack the precision required to accurately assess the true micromorphology of the palatal suture. Future investigations should explore whether alternative CBCT parameters may be more useful in addressing the challenging question of whether RME requires surgical bone weakening.

Skeletal and Dentoalveolar Changes in Growing Patients Treated with Rapid Maxillary Expansion Measured in 3D Cone-Beam Computed Tomography.

The skeletal and dental effects of rapid maxillary expansion (RME) have been extensively studied, but high-quality research is still needed to determine the three-dimensional (3D) effects of RME. The aim of this study was to compare skeletal and dentoalveolar parameters through cone-beam computed tomography (CBCT) pre- (T1) and post-treatment (T2) with respect to RME. Twenty growing patients (mean age 10.7 years) were treated with a Hyrax-type expander. A 3D CBCT was performed at T1 and T2, measuring nasal width, maxillary width, palatal height, maxillary arch perimeter, angulation of the upper first molar, and intermolar width. The mean palatal suture opening was 2.85 ± 0.62 mm (p < 0.0001). Nasal width increased 1.28 ± 0.64 mm and maxillary width 2.79 ± 1.48 mm (p < 0.0001). In contrast, palatal height was reduced 0.65 ± 0.64 mm (p < 0.0001). Regarding arch perimeter, the radicular perimeter increased 2.89 ± 1.80 mm, while the coronal perimeter increased 3.42 ± 2.09 mm (p < 0.0001). Molar angulation increased 5.62 ± 3.20° for the right molar and 4.74 ± 2.22° for the left molar (p < 0.0001). Intermolar width increased 5.21 ± 1.55 mm (p < 0.0001). Treatment with Hyrax produced a significant opening in the mean palatal suture. Also, a significant increase in nasal width, maxillary width, arch perimeter, molar angulation, and intermolar width, and a decrease in palatal height, were observed.

Unusual systemic and nondental effects of maxillary expansion therapy: A comprehensive and updated review of literature.

In dental practice, pediatric patients with a wide range of manifestations of malocclusion viz. crossbite, dental crowding, and skeletal Class III due to transverse discrepancy of the abnormally constricted maxilla or palate are found. However, the dental management of such kind of malocclusion with narrow palate needs a meticulous dental evaluation. Appliances used for treating such malocclusion conditions may include Slow-Maxillary Expansion (SME) or Rapid Maxillary Expansion (RME) orthodontic or orthopedic appliances. Considerable success has been described in the literature using the maxillary/palatal expansion modality. Unusual systemic and nondental effects of expansion appliances therapy have been described in some scientific studies. However, no comprehensive review article has been published describing the nondental and systemic effects of RME/SME therapy in Pediatric Dentistry. Considering the above scenarios, the updated and comprehensive review of the relevant literature is necessary for health professionals. Dental professionals including pediatric dentists and orthodontists need to consider such untoward or unexpected effects of RME/SME treatment modality. Hence, the current comprehensive review article has been written with the aim to meticulously describe the relevant scientific literature about nondental/extraoral and systemic effects of RME/SME appliances.

Effect of rapid maxillary expansion on masticatory and swallowing functions in children with posterior crossbite

Abstract Objective: Investigate the influence of posterior crossbite on masticatory and swallowing functions by videofluoroscopy examination and to analyze the effects of Rapid Maxillary Expansion (RME) on the same functions. Methods: A prospective longitudinal study was conducted on 32 children, 21 of them with posterior crossbite (10 girls and 11 boys, mean age 9.2 years, study group) and 11 children with no occlusal changes (6 girls and 5 boys, mean age 9.3 years, control group). The children were evaluated by an orthodontist for diagnosis, group characterization and occlusal treatment, by the otorhinolaryngology team for the assessment of respiratory symptoms, and by a speech therapist for videofluoroscopic evaluation of masticatory and swallowing parameters. The children with posterior crossbite were treated orthodontic ally using the Haas disjunctor for approximately six months and re-evaluated 5-months after removal of the appliance. Data were analyzed statistically by the Studentt-test for independent samples for comparison of the crossbite and control groups before and after treatment. Results: There was no significant difference in oral preparatory and oral transit times, nor in cycles and masticatory frequency, between the pre and post orthodontic treatment groups and the control group. Conclusion: Rapid maxillary expansion did not influence the masticatory and swallowing variables studied by videofluoroscopy. However, the data require caution in interpretation.

Extracellular vesicles derived from M1 macrophages enhance rat midpalatal suture expansion by promoting initial bone turnover and inflammation.

BACKGROUND: Midpalatal suture (MPS) expansion can be affected by many factors, and researchers have attempted to regulate the initial inflammatory stage of expansion to optimize clinical outcomes and their underlying mechanisms. This study aimed to investigate the potential effects and mechanisms of M1 macrophage small extracellular vesicles during rat MPS expansion. MATERIALS AND METHODS: RAW264.7 cells were induced to M1 or M2 polarization and, small extracellular vesicles were isolated from the polarized macrophages. Male Sprague-Dawley rats (6-7 weeks) were administered 70 ± 5 g expansion force devices for 7 days. Rats with expanders without force served as controls. M1/M2 small extracellular vesicles were injected into the MPS region (50 µg/day) in the M1 and M2 small extracellular vesicle-assisted groups, while 0.9% saline was injected into the expansion-only group. Suture width, bone mass, and morphological changes in the region of interest (ROI) were examined. RESULTS: The M1 small extracellular vesicle-assisted group showed a significantly increased MPS suture width in vivo (P < 0.001), and less bone mass was observed in the ROI (P < 0.05). Histological examination showed that the M1 small extracellular vesicle-assisted group exhibited a wider palatal area and obvious fibrous tissue rearrangement. The expression of RANKL and the number of osteoclasts were increased (P < 0.01) in the bony edges, and the p65 protein expression was significantly higher (P < 0.001). CONCLUSIONS: M1 macrophage-derived small extracellular vesicles have a positive effect in MPS expansion and increase p65 protein content and RANKL expression, thus promoting bone turnover. This study may contribute to the clinical application of small extracellular vesicles in the expansion of the palatal suture.

Changes in Molar Tipping and Surrounding Alveolar Bone with Different Designs of Skeletal Maxillary Expanders.

This study compared the buccolingual angulation (BLA) of the upper and lower first permanent molars before and after using the different methods of microimplant-assisted expansion in adults and its influence on bone insertion loss. METHODS: Cone-beam computed tomography scans taken before and after the expansion in 36 patients (29.9 ± 9.4 years) were used to assess dental and periodontal changes and compare changes between the groups. RESULTS: This research shows a statistically significant increase in the BLA of the upper first molars. An increase of the BLA of the lower molars is also observed in MARPE. Regarding the comparison between cases treated with MARPE (4.42° ± 10.25°; 3.67° ± 9.56°) and BAME (-0.51° ± 4.61°; 2.34° ± 4.51°), it was observed that upper molar torque increased significantly less in cases treated with BAME. In cases with CWRU < 96° at T0, a slight bone insertion gain was observed at T1, whereas if CWRU ≥ 96°, a slight bone insertion loss was observed. Regarding the labial cortical bone loss, a slight gain of CBW was observed in all cases. This labial cortical enlargement (T0-T1) is greater in cases where the CWRU < 96° at T0. CONCLUSIONS: Patients treated with MARPE show torque increase in the teeth selected to support the expansion appliance compared to cases treated with BAME. In cases where the BLA at T0 < 96°, an increase in thickness and cortical insertion is observed in the upper molars after treatment with disjunction appliances assisted with microscrews.

Near-Infrared Light-Controlled MicroRNA-21-Loaded Upconversion Nanoparticles to Promote Bone Formation in the Midpalatal Suture.

Rapid maxillary expansion (RME) is a common therapy for maxillary transverse deficiency. However, relapses after RME usually occur because of insufficient bone formation. MicroRNA-21 (miR-21) was reported as an important post-transcriptional modulator for osteogenesis. Herein, a photocontrolled miR-21 (PC-miR-21)-loaded nanosystem using upconversion nanoparticles (UCNPs) modified with poly(ether imide) (PEI), i.e., UCNPs@PEI@PC-miR-21, was constructed to promote bone formation in the midpalatal suture. UCNPs@PEI was constructed as the light transducer and delivery carrier. The UCNPs@PEI@PC-miR-21 nanocomplexes have good aqueous dispersibility and biocompatibility. The in vitro cell experiment suggested that UCNPs@PEI could protect PC-miR-21 from biodegradation and release PC-miR-21 into the cytoplasm under near-infrared light (NIR) irradiation. Furthermore, UCNPs@PEI@PC-miR-21 upregulated the expression of the osteogenic key markers, ALP, RUNX2, and COL1A1, at the levels of both genes and proteins. Besides, the results of the in vivo RME mice models further corroborated that photocontrollable UCNPs@PEI@PC-miR-21 accelerated bone formation with upregulating osteogenic markers of ALP, RUNX2, and osteoprotegerin and inducing fewer osteoclasts formation. In conclusion, UCNPs@PEI@PC-miR-21 nanoparticles with a NIR light could facilitate the remote and precise delivery of exogenous miR-21 to the midpalatal suture to promote bone formation during RME. This work represents a cutting-edge approach of gene therapy to promote osteogenesis in the midpalatal suture during RME and provides a frontier scientific basis for later clinical treatment.

Upper airway changes after rapid maxillary expansion: three-dimensional analyses.

The objective of this study was to evaluate volumetric changes in the upper airway using Cone Beam Computed Tomography (CBCT) in orthodontic patients with maxillary transversal hypoplasia undergoing maxillary disjunction. The influence of factors such as sex, age, and growth pattern on airway volumetric changes was also assessed. The sample consisted of 50 growing patients from the dental clinic of Cardenal Herrera CEU University of Valencia. Airway volume was measured in mm3 before treatment (T0) and after palatal disjunction (T1). The final sample included 37 subjects in the treatment group and 13 in the control group. The volume gained exclusively from the disjunction treatment was determined to differentiate it from natural growth. The control group showed a mean volume increase from 10,911.3 ± 1,249.6 mm3 to 13,168.9 ± 1,789.7 mm3, representing a mean increase of 2,257.6 mm3 or + 20.9%. The treatment group exhibited an increase from 14,126.3 ± 4,399.8 mm3 at T0 to 18,064.1 ± 4,565.9 mm3 at T1, corresponding to a gain of 3,937.8 mm3 or + 31.8%. Significant differences in airway volume were observed after palatal disjunction compared to the control group. The expansion of the maxilla led to a significant increase in airway volume in the treated patients, estimated at 5,183 mm3 (+ 41.5%).

Effect of rapid maxillary expansion on masticatory and swallowing functions in children with posterior crossbite.

OBJECTIVE: Investigate the influence of posterior crossbite on masticatory and swallowing functions by videofluoroscopy examination and to analyze the effects of Rapid Maxillary Expansion (RME) on the same functions. METHODS: A prospective longitudinal study was conducted on 32 children, 21 of them with posterior crossbite (10 girls and 11 boys, mean age 9.2 years, study group) and 11 children with no occlusal changes (6 girls and 5 boys, mean age 9.3 years, control group). The children were evaluated by an orthodontist for diagnosis, group characterization and occlusal treatment, by the otorhinolaryngology team for the assessment of respiratory symptoms, and by a speech therapist for videofluoroscopic evaluation of masticatory and swallowing parameters. The children with posterior crossbite were treated orthodontic ally using the Haas disjunctor for approximately six months and re-evaluated 5-months after removal of the appliance. Data were analyzed statistically by the Studentt-test for independent samples for comparison of the crossbite and control groups before and after treatment. RESULTS: There was no significant difference in oral preparatory and oral transit times, nor in cycles and masticatory frequency, between the pre and post orthodontic treatment groups and the control group. CONCLUSION: Rapid maxillary expansion did not influence the masticatory and swallowing variables studied by videofluoroscopy. However, the data require caution in interpretation.