Rapid Maxillary Expansion Research Articles

Complications of Surgically Assisted Rapid Maxillary/Palatal Expansion (SARME/SARPE)-A Retrospective Analysis of 185 Cases Treated at a Single Center.

Objectives: The study aims to assess and classify complications in patients treated for maxillary transverse deficiency using surgically assisted rapid maxillary/palatal expansion (SARME/SARPE) under general anesthesia. The classification of the complications aimed to assess the difficulty of their treatment as well as estimate its real cost. Methods: The retrospective study covered 185 patients who underwent surgery for a skeletal deformity in the form of maxillary constriction or in which maxillary constriction was one of its components treated by a team of maxillofacial surgeons at one center (97 females and 88 males, aged 15 to 47 years, mean age 26.1 years). Complications were divided into two groups: early complications (up to 3 weeks after surgery) and late complications (>3 weeks after surgery). In relation to the occurrence of complications, we analyzed the demographic characteristics of the group, type of skeletal deformity (class I, II, III), presence of open bite and asymmetry, surgical technique, type and size of appliance used for maxillary expansion, as well as the duration of surgery. Results: In the study group, complications were found in 18 patients (9.73%). Early complications were found in nine patients, while late complications were also found in nine patients. Early complications include no possibility of distraction, palatal mucosa necrosis, perforation of the maxillary alveolar process caused by the distractor and asymmetric distraction. Late complications include maxillary incisor root resorption, no bone formation in the distraction gap, and maxillary incisor necrosis. None of the patients required prolonged hospitalization and only one required reoperation. Conclusions: Complications were found in 18 patients (9.73%). All challenges were classified as minor difficulties since they did not suppress the final outcome of the treatment of skeletal malocclusion. However, the complications that did occur required additional corrective measures. Surgically assisted rapid maxillary expansion, when performed properly and in correlation with the correct orthodontic treatment protocol, is an effective and predictable technique for treating maxillary constriction.

Does Upper Incisors Procline following Rapid Maxillary Expansion Facemask Therapy?

Background: The present study is intended to evaluate the changes in upper incisor angulation, skeletal and dental parameters, soft-tissue and airway dimensions following rapid palatal expansion and maxillary protraction. Materials and Methods: Twenty class III subjects (mean age 11.3 years) were given bonded rapid maxillary expansion (RME) and facemask (FM) for 6 months. Pre- and posttreatment cephalogram were compared and dental, skeletal, soft-tissue, and airway changes were quantified. Results: The mean increase in SNA was 1.85° (P < 0.001) while SNB decreased by 1.85° (P < 0.001). Upper and lower face height increased (UFH 1.1 mm, P < 0.05; LFH 2.92 mm, P < 0.001). Upper lip moved forward (E line U/lip 1.27 mm, P < 0.001; S line U/lip 1.3 mm, P < 0.01). 1-SN decreased by 4.35° and 1-NA decreased by 4.50° with P < 0.01. Overjet improved by 3.07 mm (P < 0.001). Conclusion: RME and FM therapy resulted in maxillary forward movement; mandible rotated downward and backward; UFH and LFH increased. The upper lip exhibited forward movement, resulting in a less concave profile. Upper incisor retroclined and there was increase in overjet and no changes in airway dimensions. The upper incisors following RME and FM does not always procline; it is decided by the interaction of four factors – mesial dental movement, rotation of maxillary/occlusal plane, amount of expansion with RME (expansion effect), and reverse twin block if incorporated with FM.

A Roentgenographic Comparative Investigation of The Midpalatal Suture Obliteration Evidenced Through Occlusal and Cone Beam CT Radiographs

Background: Assessing the midpalatal suture (MPS) maturation is crucial to successfully predict rapid maxillary expansion. Therefore, radiographic measurement of the suture width is vital for treatment planning. This study compared MPS ossification using cross-sectional maxillary occlusal radiographs and cone-beam computed tomography (CBCT) scans to aid clinicians in making better treatment decisions. Methods: In this study, 33 patients were selected as the study cohort and were categorized into two distinct groups according to their chronological age. Group I included individuals in the growth phase, aged between 8 to 16 years, while Group II encompassed post-adolescent and young adult participants aged between 16 to 25 years. The percentage of MPS ossification was calculated using the suture obliteration index calculated on axial cross-sectional images. Statistical analysis was performed utilizing the student t-test with a significance level set at 0.05. Results: No significant difference was found between occlusal radiographs and CBCT scans in the assessment of MPS ossification in the anterior part (P>0.05). However, significant differences existed in the suture obliteration index in anterior part (P=0.031) and posterior part (P=0.035), with higher mean values obtained by occlusal radiographs. In contrast, significant differences favoring CBCT were found in the anterior part (P<0.001) with higher mean values; no significant difference was found in the posterior part. Lastly, significant difference did not exist in the posterior part between the two imaging modalities (P>0.05). Conclusion: For MPS assessment, both CBCT and occlusal radiography can provide predictable results. However, it is notable that CBCT still has an upper hand in providing better and more accurate results.

Medium-term effects of rapid maxillary expansion on nasal cavity and pharyngeal airway volumes considering age as a factor: A retrospective study

ObjectivesThe medium-term effects of rapid maxillary expansion (RME) on nasal cavity (NC) and upper airway (UA) dimensions based on chronological age are still unclear. This retrospective study evaluated the medium-term changes occurring in the NC and pharyngeal airways (PA) after RME in two distinct age-based cohorts of patients. MethodsThis retrospective study included 48 subjects who underwent RME grouped in two cohorts: a 6–9-year-old group (EEG group: early expansion group - 25 subjects) and an 11–14-year-old group (LEG group: late expansion group - 23 subjects). NC and PA volumes were analyzed from CBCT imaging segmentation before RME (T0) and twelve months after RME (T1). The amount of maxillary expansion (PW) and minimal cross-sectional area (CSmin) were also considered. ResultsAll PAs’ volumetric sub-regions, CSmin and PW showed a significant volumetric increment (p < 0.05). Inter-group comparisons showed significant differences (p < 0.05) for nasopharynx and CSmin parameters (p < 0.05), while no significant changes were recorded for the other UA's sub-regions and PW (p > 0.05). According to a deviation analysis, part of the UA increase (more marked for the nasopharynx area) may have occurred due to reduced adenotonsillar tissues, which were larger in the EEG group. ConclusionsTwelve months after treatment, clinicians should not expect changes in the UAs dimensions to be solely related to treatment effects of RME; instead, normal craniofacial growth changes and spontaneous regression of the adenotonsillar tissue could represent the most significant factors influencing UAs changes. Clinical SignificanceFrom the clinical perspective, the results of the present study encourage caution when considering the therapeutic effects of RME on airways dimensions.

Temporomandibular joint disc position and shape in patients submitted to two protocols of rapid maxillary expansion and face mask therapy: A randomized clinical trial.

The objective of this prospective study was to assess possible changes in the position and shape of the temporomandibular joint (TMJ) articular disc in patients treated with two protocols of rapid maxillary expansion (RME) and face mask (FM) therapy. A sample of 88 patients with Class III or Class III subdivision malocclusions, aged between 6 and 13 years, were consecutively selected and divided into three groups (G): G1-34 patients were treated with RME, followed by FM therapy; G2-34 patients were treated using RME according to modified alternate rapid maxillary expansion and constriction (ALT-RAMEC) protocol, followed by FM therapy. These treated groups were randomly (1:1 allocation ratio) distributed according to the two treatment protocols. G3 - Control Group - 20 untreated patients were followed. Magnetic resonance imaging (MRI) TMJs were obtained before (T1) and after (T2) a treatment period or follow-up. McNemar test, Fisher's exact test and intra- and inter-observer concordance (K) were performed (p ≤ .05). There were no statistically significant differences in the baseline cephalometric variables at T1 between the groups. There were statistically significant differences between the groups (p < .001) in relation to the disc shape in T1, since G1 (8 TMJs -11.76%) presented higher occurrences of altered forms in comparison with G2 (no changes). No significant differences were observed in disc position CM and OM (G1 - p > .999; G2 - p = .063; G3 - p = .500) and shape (G1 - p > 0.999; G2 - p = .250; G3 - not calculable), between T1 × T2, in any of the groups studied. The two treatment protocols did not have adverse effects on the position and shape of the TMJ disc, in a short-term evaluation.

Evaluation of Bone Thickness and Density Values in Resistance Regions in Rapid Maxillary Expansion Using Computed Tomography.

This study used computed tomography (CT) to compare the bone thickness and density values around the zygomaticomaxillary, zygomaticotemporal, and pterygomaxillary sutures that are resistant to rapid maxillary expansion (RME) treatment according to age, sex, and cervical vertebrae maturation (CVM) stage. The study included 200 paranasal sinus records obtained for medical diagnosis and examination in a radiology clinic. The records provided data on 110 males and 90 females aged between 4 and 28 years. Bone thickness and density values around the zygomaticomaxillary, zygomaticotemporal, and pterygomaxillary sutures were measured using CT imaging. The correlations of bone thickness and density values with the variables of age, sex, and CVM stage were evaluated. No statistically significant difference was revealed between the bone thickness values around the zygomaticomaxillary and zygomaticotemporal sutures and age, sex, CVM stage, and the right and left regions of the same individual ( P >0.05). A strong correlation was identified between Hounsfield units (Hu) values on bone density in all 3 regions and age and sex ( P <0.001). No correlation was found between the CVM stage and density values around the zygomaticomaxillary, zygomaticotemporal, and pterygomaxillary sutures ( P >0.05). The Hu values of the records from females were higher than those of males in all age groups. It was observed that with increasing age, bone density values increased in all 3 regions, and thus circummaxillary region's Hu value increased.

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

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. 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). 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). 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. FTO contributes to the osteogenic differentiation of SuSCs and plays a promoting role in midpalatal suture bone remodeling during the RME.

Impact of Non-Surgical and Surgically Assisted Rapid Maxillary Expansion Procedures upon the Periodontium: A Systematic Review

Background: Scarce evidence is available regarding the occurrence and prevalence of hard/soft tissue deficiencies among patients undergoing surgically assisted rapid maxillary expansion (SARME) as compared to non-surgical rapid maxillary expansion (NSRME) approaches. The purpose of this study is to evaluate the effect of NSRME and SARME upon the periodontal structures. Methods: A literature search was performed to identify studies that fulfilled pre-established eligibility criteria, evaluating changes in the periodontium (e.g., probing depths) and hard/soft tissue deficiencies (e.g., bone levels, gingival recession) within patients undergoing NSRME and SARME procedures. Results: A total of 21 articles were included in the present review. Four of them evaluated the outcomes of both NSRME and SARME procedures, while six and eleven studies analyzed NSRME alone and SARME alone, respectively. The incidence of hard (e.g., changes in buccal bone width/height) and soft tissue deficiencies (e.g., gingival recession, keratinized tissue, and clinical attachment level) is slightly increased among patients undergoing maxillary expansion with worsened outcomes during NSRME procedures. Conclusions: The impact of NSRME and SARME upon the periodontium remains inconclusive.

Awareness and attitude among general dentists and orthodontists toward obstructive sleep apnea in children.

This study aimed to investigate Italian dentists' knowledge of and attitudes toward obstructive sleep apnea (OSA) in children. An anonymous questionnaire was prepared using Google Forms and sent to dentists in Italy through private social platforms. The first part of the questionnaire contained basic demographic data questions, and the second part included items about pediatric OSA. A total of 125 responses were collected within 1 month. The interviews revealed gaps in undergraduate and post-graduate training on OSA, and consequently, low self-evaluation of knowledge and self-confidence in managing young patients with OSA. Dentists showed unfavorable attitudes and poor knowledge of the general findings, risk factors, and consequences of pediatric OSA but demonstrated good knowledge of the beneficial effects of rapid maxillary expansion. Orthodontists showed a more favorable attitude and better recognition of the craniofacial features associated with OSA. In addition, a comparison was made between dentists who had graduated more than 5 years ago and new graduates, and differences were found in undergraduate education, which was better for new graduates, and a small number of questions were better answered by experienced dentists. This study showed a lack of knowledge about pediatric OSA and its management among Italian dentists, revealing the need to update the dentistry curriculum and organize educational interventions.

Cephalometric changes of pushing splints 3 compared to rapid maxillary expansion and facemask therapy on the airway space in class III growing patients: A randomized clinical trial.

Early orthopaedic treatment with rapid maxillary expansion (RME) associated with facemask (FM) has been shown to be effective in correcting Class III malocclusions in children. Treatment with pushing splints 3 (PS3) has shown to correct skeletal discrepancies in Class III growing patients. However, the effects of orthopaedic treatment on the upper airways in children with Class III malocclusion is controversial. The aim of this study was to evaluate the cephalometric changes in the airways of PS3 compared to the RME/FM protocol. In this study, 48 patients with Class III malocclusion (age range 5.5-8.5 years old) were selected for this study, and 24 were treated with PS3 appliance and 24 with RME/FM therapy. Lateral cephalograms before (T0) and at the end of the treatment (T1) were analysed to compare pharyngeal spaces. Paired and unpaired t tests were used for data analysis (P < .05). A total of 41 patients (21 patients for the PS3 group, 11 males and 10 females, mean age 7.0 ± 1.2 years; 20 patients for the RME/FM group, 10 males and 10 females, mean age 7.2 ± 1.3 years) were included. The results showed a statistically significant (P < .05) increase in the nasopharyngeal space after both therapies. However, the effects were similar considering that there were no differences between groups for the assessed variables at T0-T1. Early treatment of Class III malocclusion with PS3 does not induce a statistically significant increase in the sagittal airway space compared to RME/FM. The absence of untreated group could not define the role of growth in the increase of space.

Dento-Alveolar Changes after Maxillary Hybrid Expansion and Multi-Bracket Therapy: A Comparative Study at Three Different (Vertebral) Maturation Stages

Background: Rapid maxillary expansion is a common therapy when a palatal transversal discrepancy occurs. Different anchorage solutions have been proposed to obtain an effective skeletal expansion, even for adult patients. The aim of the present research was to evaluate the dentoskeletal effects of a hybrid expander and multi-bracket therapy, considering three groups of patients with different cervical vertebral maturation (CVM) stages. Materials and Methods: The study evaluated 68 consecutively treated patients. The age of the patients varied from 7 to 27 years old (mean age 13.45). The sample was divided into the following three groups based on CVM stage at the start of treatment: Group 1 (CS1–CS2) included 21 patients (mean age 10.21, SD 1.34), Group 2 (CS3–CS4) included 28 patients (mean age 13.37, SD 1.37) and Group 3 (CS5–CS6) was composed of 19 patients (mean age 17.14, SD 3.48). Each patient underwent orthodontic therapy where the first step was a palatal expansion by means of a hybrid expander; afterwards, the therapy was completed with a multi-bracket appliance. Expansion and torque values were observed at the end of treatment on digital models. Results: Significant intragroup differences in transversal expansion were found over time for all parameters in all groups. No significant differences were found among groups for longitudinal changes. No significant differences were found among groups for longitudinal changes of torque. Conclusions: The tooth–bone-borne maxillary expander and multi-bracket produced a significant clinical expansion with negligible dental compensation. The effect of the maxillary expansion and multi-bracket therapy showed no differences among the maturation groups in regard to transversal diameter changes and torque values.

Upper airway outcomes on pediatric OSA after interceptive orthodontic treatment with RME - rapid maxillary expansion: a clinical study

Upper airway outcomes on pediatric OSA after interceptive orthodontic treatment with RME - rapid maxillary expansion: a clinical study

The effects of rapid maxillary expansion on persistent pediatric snoring post-tonsillectomy

The effects of rapid maxillary expansion on persistent pediatric snoring post-tonsillectomy

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.

Dental and Alveolar Arch Widths in Normal Occlusion and Class II Division 1 Malocclusion

This study was to evaluate and compare dental arch and alveolar widths of patients with Class II division one malocclusion with group of untreated normal occlusion subjects. This study was performed using measurement on dental casts of 30 normal occlusion and 30 Class II division 1 malocclusion of Iraqi sample aged 15-22 years. T-test was applied for comparing the groups , the finding of this study indicated that maxillary interpremolar width, maxillary canine, maxillary premolar and maxillary first molar and mandibular premolar and molar alveolar widths were found significantly narrower in the Class II division 1 group when compared with the normal occlusion sample (P&lt;.001). The maxillary and mandibular intermolar and mandibular intercanine alveolar widths were statistically significantly larger in the Class II division 1 group ( P&lt;.01) . Maxillary molar teeth in subjects with Class II division 1 malocclusion tend to incline to the buccal to compensate the insufficient alveolar base therefore rapid maxillary expansion rather than slow maxillary expansion should be considered during treat ment of Class II division 1 patients. The results of our study sugg ested that transverse discrepancy in Class II division one maloccl usion originated from upper posterior teeth and maxillary alveolar base.

Comparison of the effects on facial soft tissues produced by rapid and slow maxillary expansion using stereophotogrammetry: a randomized clinical trial

ObjectiveTo compare the effects on facial soft tissues produced by maxillary expansion generated by rapid maxillary expansion (RME) versus slow maxillary expansion (SME).Materials and methodsPatients in the mixed dentition were included with a transverse discrepancy between the two arches of at least 3 mm. A conventional RME screw was compared to a new expansion screw (Leaf expander) designed to produce SME. Both screws were incorporated in a fixed expander. The primary outcome was the difference of the facial tissue changes in the nasal area measured on facial 3D images captured immediately before application of the expander (T0) and after one year of retention, immediately after the expander removal (T1). Secondary outcomes were soft tissue changes of other facial regions (mouth, lips, and chin). Analysis of covariance was used for statistical analysis.ResultsFourteen patients were allocated to the RME group, and 14 patients were allocated to the SME group. There were no dropouts. Nasal width change showed a difference between the two groups (1.3 mm greater in the RME group, 95% CI from 0.4 to 2.2, P = 0.005). Also, intercanthal width showed a difference between treatments (0.7 mm greater in the RME group, 95% CI from 0.0 to 1.3, P = 0.044). Nasal columella width, mouth width, nasal tip angle, upper lip angle, and lower lip angle did not show any statistically significant differences. The Y-axis (anterior–posterior) components of the nasal landmark showed a statistically significant difference between the two groups (0.5 mm of forward displacement greater in the RME group, 95% CI from 0.0 to 1.2, P = 0.040). Also, Z-axis (superior-inferior) components of the lower lip landmark was statistically significant (0.9 mm of downward displacement in favor of the RME group, 95% CI from 0.1 to 1.7, P = 0.027). All the other comparisons of the three-dimensional assessments were not statistically significant.ConclusionsRME produced significant facial soft tissue changes when compared to SME. RME induced greater increases in both nasal and intercanthal widths (1.3 mm and 0.7 mm, respectively). These findings, though statistically significant, probably are not clinically relevant.Trial registration ISRCTN, ISRCTN18263886. Registered 8 November 2016, https://www.isrctn.com/ISRCTN18263886?q=Franchi&filters=&sort=&offset=2&totalResults=2&page=1&pageSize=10

The Impact of Systemic Simvastatin on Bone Remodeling Following Rapid Maxillary Expansion: An In Vivo Study

A midpalatal suture contention after rapid maxillary expansion (RME) is a major orthodontic challenge. The objective of this study is to evaluate the effect of systemic simvastatin on suture bone remodeling after disjunction. For that, 15 Wistar rats were used. In 10, orthodontic appliances were installed and activated for 5 days for RME. These animals were randomly divided into two groups: control (CT, n = 5) and simvastatin (SVT, n = 5). Also, animals without intervention (HG, n = 5) were used. In the SVT and CT groups, 5 mg/kg of simvastatin and distilled water were administered by gavage, respectively, for 20 consecutive days. Then, the animals were euthanized and scanned in micro-computed tomography (µCT). The images were analyzed through pixel linear measurement at four different points (P1, P2, P3 and P4), in the intra-incisor distance (DI) and in the suture distance (SD). Microtomographic parameters, such as cortical bone area (Ct.Ar), cortical area fraction (Ct.Ar/Tt.Ar), and cortical thickness (Ct.Th), were obtained. Also, bone volume fraction (BV/TV) and empty space (EV) were extracted. Then, histological slides were prepared for descriptive and histomorphometric analysis. There was a statistically significant difference in the linear measurements, microtomographic parameters, and histomorphometric results between the experimental groups. In conclusion, simvastatin demonstrated an osteoinductive and antiresorptive effect in the palatine suture region after RME.

Photographic analysis of orofacial soft tissue alterations related to rapid maxillary expansion in pediatric patients.

Maxillary transverse deficiency is widely recognized as one of the most common skeletal issues in orthodontics, and rapid maxillary expansion (RME) is commonly employed as a treatment method. This study aimed to investigate the impact of RME on the soft tissues of the orofacial region in pediatric patients. The study included two groups: an experimental group comprising 30 patients (16 females and 14 males) with maxillary skeletal transverse deficiency who required rapid maxillary expansion (RME), and a control group consisting of patients (10 females and 10 males) who did not require RME or orthodontic treatment. Frontal and profile photographs were taken before and after RME for both groups. Frontal photographs were used to obtain 12 linear measurements, while profile photographs were used to perform 2 linear and 2 angular measurements using the "protractor" and "pixel ruler" software. Burstone-Legan, Steiner and Rickett's analyses were performed to determine the locations of the upper and lower lips. Student t-test, paired samples t-test and Mann-Whitney U test were used to evaluate the data. In the experimental group, there was a statistically significant increase in nose width and intercommissural distance at the end of the treatment (p < 0.05). Similarly, both the experimental and control groups showed a statistically significant increase in the dorsum of nose length at T2 compared to the initial measurement (p < 0.05). Furthermore, the male participants in the experimental group exhibited a statistically significantly higher increase in nose length and dorsum of the nose during the T1 and T2 periods compared to the female participants in the experimental group (p < 0.05). RME may lead to changes in soft tissues in pediatric patients and was observed to be gender-specific. However, these changes were not clinically noticeable, and long-term follow-up studies are needed to determine the long-term effects of these changes.

Exploring the potential of rapid maxillary expansion and masticatory muscle activity in unilateral posterior crossbite.

This systematic review and meta-analysis aimed to evaluate if rapid maxillary expansion improves the activity of the masticatory muscles (masseter and temporal) in patients with unilateral posterior crossbite. Searches were performed in PubMed/MEDLINE, Scopus, Web of Science, Embase, Cochrane Library, and grey literature. A manual search of orthodontic journals was also performed. Randomized clinical trials or longitudinal prospective studies were eligibles. Meta-analyses were conducted using R software with the "Meta" package, applying mean differences with a 95% confidence interval. Risk of bias was assessed using the Newcastle-Ottawa scale, and evidence certainty was evaluated using GRADE. Nine articles were included. Qualitative analysis showed that RME treatment in patients with unilateral posterior crossbite showed a positive correlation with improvement in masseter and temporalis muscle activity. Meta-analyses indicated a significant difference for all models of muscle activity after treatment with rapid maxillary expansion, except for the temporal muscle in the force exerted on the maximum voluntary clenching on cotton rolls. The studies showed low bias risk, and the evidence certainty for each analysis was generally low to very low. This investigation demonstrated the benefits of R rapid maxillary expansion in treating unilateral posterior crossbite and its potential therapeutic effects on the masticatory muscles. Key words:Rapid maxillary expansion, masticatory muscles, unilateral posterior crossbite, systematic review, meta-analysis.

Comparing the efficiency of maxillary protraction using digital cooperation monitoring in ages 4–7 and 8–11: a prospective study

Abstract Objectives This study compares the effectiveness of face mask therapy applied after rapid maxillary expansion (RME) in 4- to 11-year-old patients with objective co-operation data collected using thermal sensors. The null hypothesis was that there would be no difference in the effectiveness of the maxillary protraction. Materials and method Initial and post-treatment lateral cephalometric radiographs were taken of patients with maxillary retrognathia, aged between 4 to 7 years (6.1 ± 1.88, n = 13) and 8 to 11 years (9.4 ± 1, n = 12) of age. An RME was performed for at least 10 days. The face mask protraction force was set to 450 g per side, and the recommended usage was 10 hr per day. TheraMon® microsensors were integrated into the face mask. Results The daily usage was significantly higher in the younger age group (8.9 ± 1.8 hr) compared to the older group (7.1 ± 0.9 hr). The SNA angle, A-Nasionperp (mm), ANB angle, Wits (mm), maxillary depth, ANS-Me (mm), the molar relationship (mm) and overjet (mm) significantly increased in both groups. Co-A (mm), the saddle angle, articular angle and UL-E Line (mm) showed a significant increase only in the older group, while the L1-A/Pg decreased significantly. The SNB angle decreased significantly only in the younger group. There was no statistically significant difference in the delta values between the two groups. Conclusion The null hypothesis was partly rejected since no difference was observed in the examined skeletal and soft tissue parameters.