Surgically assisted rapid maxillary expansion: current concepts of minimally invasive approaches.

Studies have consistently shown an association of the Le Fort I osteotomy with undesirable adverse events in the nasolabial region, including lengthening and thinning of the upper lip, a reduction in upper vermilion exposure, and nasal base enlargement. Various minimally invasive techniques have been developed based on knowledge collected over recent decades on the aetiopathogenesis of these aesthetic impairments. The common scope of these techniques is to reduce the damage to the facial soft tissues and achieve a sound and spontaneous healing process, avoiding those procedures that are commonly used to counteract undesirable aesthetic changes. This paper provides a summary of the aetiopathogenesis of these adverse events, as well as an overview of current concepts in minimally invasive surgically assisted rapid maxillary expansion (miSARME).

Dentoalveolar, periodontal and skeletal effects of maxillary expansion techniques assisted by temporary anchorage devices compared with conventional protocols in growing patients with transverse maxillary deficiency: A systematic review and meta-analysis.

OBJECTIVES: To synthesise the dentoalveolar, periodontal and skeletal changes that occur when using maxillary expansion techniques assisted by temporary anchorage devices compared to conventional protocols. METHODS: Five databases and grey literature were consulted, up to December 2023, focusing on intervention designs and excluding other type of studies. The quality assessment was conducted by using the adaptation for orthodontics of the CONSORT statement, the guidelines for reporting non-randomised studies, the RoB-2 tool, and the ROBINS-I tool. A descriptive summary and meta-analysis using RevMan 5.4 were performed. RESULTS: Nine clinical trials were included (n=377 patients, mean age 13.2±0.6) with a diagnosis of transverse maxillary deficiency. The analysed studies showed qualitative dentoalveolar and periodontal changes after expansion, which were greater on the maxillary first premolars in tooth-borne appliances. Meta-analyses for some effects were included from two studies (n=64); patients who used tooth-borne appliances had greater effects of buccal intercoronal width between the premolars with statistically significant differences (Std Mean difference 2.34; 95% CI: 0.04-4.65 p=0.05). Conversely, those patients who used bone-borne or hybrid appliances had greater effects of buccal intercoronal width between molars with statistically significant differences (Std Mean difference -0.64; 95% CI: -1.38-0.10; p=0.09). CONCLUSIONS: According to the studies analysed, all measurements increased in the intervention groups after expansion. Quantitative analyses show different findings at dentoalveolar level when tooth-borne, bone-borne or hybrid appliances are considered. Nevertheless, the results should be taken with caution due to the heterogeneity of the studies. The protocol was registered at PROSPERO (CRD42021283170), with no funding to report.

Posterior crossbite corrections in the early mixed dentition with quad helix or rapid maxillary expander: a cost-effectiveness analysis of a randomized controlled trial.

BACKGROUND: Unilateral posterior crossbite is a common malocclusion, and early treatment is recommended to enable normal growth. There are several possibilities regarding choice of appliances used for correcting this malocclusion; however, when treatment is financed by public funds the decision needs to be based not only on the effects but also on the effect in relation to the costs. OBJECTIVES: The aim was to perform a cost-effectiveness analysis comparing quad helix (QH) and rapid maxillary expanders (RME; hyrax-type) in children in the early mixed dentition. MATERIAL AND METHODS: Seventy-two patients were randomized to treatment with either QH or RME, at two different centres. Data were collected from the patient's medical records regarding success rate, number of visits, total treatment time, emergency visits, and so forth, together with answers from patient questionnaires concerning absence from school and use of analgesics. A cost-effectiveness analysis with both an intention-to-treat (ITT) and a per-protocol approach was performed, as well as a deterministic sensitivity analysis. RESULTS: The success rate, one year after the completion of the expansion, was equal between groups according to the ITT approach. From a healthcare perspective, the mean cost difference between RME and QH was €32.05 in favour of QH (P = 0.583; NS). From a societal perspective, the mean cost difference was €32.61 in favour of QH (P = 0.742; NS). The total appliance cost alone was higher in the RME group €202.67 resp. €155.58 in the QH group (P = 0.001). The probability of RME having a higher cost was 71% from a healthcare perspective and 62.7% from a societal perspective. The total treatment time was 97 days longer in the QH group. In the deterministic sensitivity analysis, when using a higher valuation of the children's educational loss, the QH becomes €58 more costly than the RME. There was a statistically significant difference in chair time and visits between centres (P < 0.001). CONCLUSION: The difference in costs between RME and QH is not statistically significant, however, there is a slightly higher probability that RME is more expensive than QH with a mean cost of an additional €32 per patient from a healthcare perspective. Different work procedures at different centres indicate that logistics around the patient's treatment is a more important aspect than appliance used to decrease the number of visits and save chair time and thereby also costs.

Biomechanics of conventional and miniscrew-assisted rapid palatal expansion.

Posterior Crossbite is a common condition resulting because of transverse maxillary deficiency. The growth of the craniofacial complex finishes first in the transverse dimension, followed by sagittal and vertical dimensions. Conventional rapid palatal expansion (RPE) appliances are commonly used to correct transverse maxillary deficiency. Although RPE is efficient in correcting posterior crossbite, it results in dental side effects such as buccal tipping of maxillary molars, root resorption, bone dehiscence, and relapse. Mini-implant-assisted RPE has been introduced to increase the skeletal effects of expansion especially in patients with increased maturation and greater interdigitation of midpalatal suture. This article will review the biomechanics of RPE and mini-implant-assisted RPE. Additionally, the different designs of MARPE and the long-term clinical effects of expansion appliances will also be discussed in detail.

Effects of minimally invasive surgical and miniscrew-assisted rapid palatal expansion (MISMARPE) on the nasal cavity and upper airway: a comparative cohort study.

This study was performed to evaluate the impact on the upper airway and nasal cavity of a new minimally invasive surgical and miniscrew-assisted rapid palatal expansion (MISMARPE) technique for the treatment of adult patients with transverse maxillary deficiency, in comparison to surgically assisted rapid palatal expansion (SARPE). Computed tomography scans of 21 MISMARPE and 16 SARPE patients were obtained preoperatively (T0) and at the end of the activation period (T1) and analysed. Linear and volumetric measurements were performed in the dental, alveolar, nasal cavity, and oropharynx regions. Generalised estimating equations were used to consider the intervention time and surgery type, and their interaction. In both groups, measurements were increased at T1 (P < 0.001), except for oropharynx volume (P > 0.05). A greater expansion in nasal cavity floor and median palatal suture was shown for MISMARPE when compared to SARPE (P < 0.001), with the same degree of expander activation (P = 0.094). A trapezoidal (coronal plane) and 'V' shape (axial plane) expansion pattern, was observed after MISMARPE. Both surgical techniques were effective for maxillary expansion in adults. However, MISMARPE was performed without osteotomy of the pterygomaxillary suture, in an outpatient setting and with local anaesthesia.

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.

Comparison of 3D-printed and laboratory-fabricated Hyrax on stress distribution and displacement of the maxillary complex: a 3D finite element study.

OBJECTIVE: To analyze and compare the effects of a traditional laboratory-fabricated Hyrax expander (T-Hyrax) and two different 3D-printed Hyrax expander models relative to tension points, force distribution, and areas of concentration in the craniofacial complex during maxillary expansion using finite element analysis. MATERIALS AND METHODS: Three maxillary expanders with similar designs, but various alloys were modeled: a T-Hyrax, a fully printed Hyrax (F-Hyrax), and a hybrid printed Hyrax (H-Hyrax). The stress distributions and magnitude of displacements were assessed with a 5 mm expansion in a symmetrical finite element model. The areas of interest included the teeth, alveolar processes, midpalatal suture, nasal complex, circummaxillary sutures (CS), and the expanders themselves. RESULTS: The highest stress value (29.2 MPa) was found at the midpalatal suture of the F-Hyrax, while the lowest stress (0.90 MPa) was found at the temporozygomatic suture in the T-Hyrax. On average, the F-Hyrax increased stress at the CS by 24.76% compared with the T-Hyrax and H-Hyrax. The largest displacements were found at the upper incisor (U1) and anterior nasal spine (ANS). The findings indicated an average increase of 12.80% displacement at the CS using the F-Hyrax compared to the T-Hyrax. CONCLUSION: The F-Hyrax exerts more stress and displacement on the maxilla than both the T-Hyrax and H-Hyrax, where the weak link appears to be the solder joint.

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

OBJECTIVE: 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. METHODS: 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). RESULTS: 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. CONCLUSION: The two treatment protocols did not have adverse effects on the position and shape of the TMJ disc, in a short-term evaluation.

Skeletal and dental effects of function-generating bite appliance compared to rapid palatal expander and untreated controls.

INTRODUCTION: Maxillary expansion is a fundamental interceptive orthodontic treatment, which can be achieved through either a rapid expansion protocol or functional devices. However, no data exist about the efficacy of functional devices in achieving skeletal expansion. Therefore, the aim of this study was to compare the effects of the rapid palatal expander (RPE) and the function-generating bite type M (FGB-M) on the transversal dimension of the maxilla, and on the maxillary and mandibular dental arch width. METHODS: One hundred eighty-one skeletal Class I patients, aged between 6 and 12 years and with a cervical vertebral maturation stage II or III, with maxillary transversal deficiency were retrospectively enrolled; among these 55 were treated with FGB-M, 73 were treated with RPE and 51 were untreated subjects retrieved from historical databases. The pre-treatment (T0) and post-treatment (T1) frontal cephalograms were retrieved, and the maxillary and mandibular widths, and the distance between upper and lower first molars were measured. T1-T0 interval was of 17.3 months (RPE), 24.6 months (FGB-M) and 18.2 months (controls). RESULTS: The statistical analysis showed that there were no statistically significant differences between the RPE and FGB-M groups regarding skeletal and dental expansion, while the untreated control group differed significantly from the other two groups. CONCLUSION: The comparison between patients treated with RPE and FGB-M showed that there were no statistically significant differences between the RPE and FGB-M groups regarding the amount of skeletal expansion and dental arch width, suggesting that both appliances can be used to achieve similar results.

Evaluation of transpalatal distraction in cleft palate patients.

PURPOSE: The aim of this study was to evaluate the effect of combining a bone-borne palatal expander (distractor) with a maxillary osteotomy in the treatment of narrowed maxillae in treated cleft palate patients. Few articles in the literature isolated the effects of transpalatal distraction in cleft patients and most either excluded cleft patients or grouped them with non-cleft patients. The hypothesis is that the use of a bone-borne palatal expander in conjunction with a maxillary osteotomy would improve the amount of maxillary expansion at the anterior segment with less tipping of the segments and provide a harmonious arch form. METHODS: We studied four patients above 14 years of age with repaired cleft palate and progressive anterior constriction of the arch. All patients received a bone-borne distractor (UNI-Smile Distractor, Titamed, Belgium) combined with a LeFort I level osteotomy without pterygomaxillary disjunction. Dental models and CBCT measurements were used to analyze the skeletal and dental effects of the intervention. RESULT: All the patients who completed the trial had satisfactory expansion and normalization of the maxillary arch form. The average increase in the intercanine distance was 12.9 mm while the average increase in the intermolar distance was 7.2 mm. No significant change in molar inclination or buccal bone thickness was observed. CONCLUSION: The use of bone-borne palatal expanders aided by a maxillary osteotomy (transpalatal distraction) in treated cleft palate patients can provide a harmonious arch form in adolescent and adult patients. This trial was registered in the clinical trials registry with the ID NCT03837652 on February 12, 2019.

Effects of SARPE and MISMARPE on correction of transverse maxillary deficiency: A preliminary comparative evaluation.

AIM: The present study was designed to compare, on cone-beam computed tomography imaging, the skeletal and dental effects of the SARPE (Surgically assisted rapid palatal expansion) and MISMARPE (Minimally Invasive Surgical and Miniscrew-Assisted Rapid Palatal Expansion) techniques. MATERIALS AND METHODS: The sample of adult patients with transverse maxillary deficiency (TMD) was divided into two groups, and scans were obtained preoperatively (T0) and immediately after completion of expansion (T1). The posterior and anterior linear transverse distances of the maxilla and the angulation of the maxillary first molars were evaluated. The data were entered into a generalized estimating equations model to verify the postoperative effects of the different techniques. RESULTS: None of the techniques caused any appreciable change in the angulation of the molars. The skeletal changes were similar, with significantly greater gains in the nasal fossa and intermaxillary distance when using the MISMARPE. CONCLUSION: The technique can be an effective and lower morbidity alternative to SARPE.

Comparison of maxillary transversal changes between auxiliary beta-titanium expansion arch and miniscrew-assisted rapid palatal expansion.

OBJECTIVE(S): This study compared buccal bone thickness, dental inclinations and maxillary transverse width dimensions changes between auxiliary beta-titanium expansion arch (AEA) and miniscrew-assisted rapid palatal expansion (MARPE). MATERIALS AND METHODS: The sample consisted of 29 patients, aged between 18 and 40 years, with transverse maxillary deficiency and treated without extractions, divided into two groups: group AEA: comprised 13 individuals (initial mean age: 29.23 ± 9.13 years) treated using auxiliary beta-titanium expansion arch; group MARPE: comprised 16 patients (initial mean age: 24.92 ± 7.60 years) treated with miniscrew-assisted rapid palatal expansion. Buccal bone thickness, dental inclinations and transverse width dimensions (dental, nasal base and jugular) were measured in cone-bean computed tomographies at pre- and post-treatment stages. The variables were compared using the independent t-test. RESULTS: The buccal bone thickness was similar for both groups at the post-treatment stage. The second premolars were significantly more buccal inclined in the AEA group and the right maxillary first molars in the MARPE group. The intercanine and intermolar distances were statistically significantly greater in the MARPE group. Changes in dental arch transverse dimensions were significantly greater for the MARPE group. CONCLUSION: Both treatment protocols corrected the maxillary transverse discrepancy; however, MARPE provided greater correction.

Convolutional neural network-assisted diagnosis of midpalatal suture maturation stage in cone-beam computed tomography.

OBJECTIVES: The selection of treatment for maxillary expansion is closely related to the calcification degree of the midpalatal suture. A classification method for individual assessment of the morphology of midpalatal suture in cone-beam computed tomography (CBCT) is useful for evaluating the calcification degree. Currently, convolutional neural networks (CNNs) have been introduced into the field of oral and maxillofacial imaging diagnosis. This study validated the ability of CNN models in assessing the maturation stage of the midpalatal suture. METHODS: The existing CNN model ResNet50 was trained to locate the CBCT transverse plane which contained a complete midpalatal suture. ResNet18, ResNet50, RessNet101, Inception-v3, and Efficientnetv2-s models were trained to evaluate the midpalatal suture maturation stage. Multi-class classification metrics, accuracy, recall, precision, F1-score, and area under the curve values from the receiver operating characteristic curve were used to evaluate the performance of the models, and gradient-weighted class activation map technology was utilised to visualise five midpalatal suture maturation stages for each model. RESULTS: Resnet50 demonstrated an accuracy of 99.74 % in identifying the transverse plane that contained the complete midpalatal suture. The highest accuracies achieved on the two-stage, three-stage, and five-stage maturation classification tests were 95.15, 88.06, and 75.37 %, all of which exceeded the average accuracy of three experienced orthodontists. CONCLUSIONS: The CNN model can locate the plane of the midpalatal suture in CBCT images and can assist clinicians in assessing the maturation stage of the midpalatal suture to select the means of maxillary expansion. CLINICAL SIGNIFICANCE: The application of artificial intelligence on CBCT midpalatal suture plane localisation and maturation stage evaluation enhances diagnostic and treatment efficiency and accuracy of individual assessment of midpalatal suture calcification degree. Additionally, it assists the clinical palatal expansion technique in achieving ideal results.

Biomechanical behavior of three maxillary expanders in cleft lip and palate: a finite element study

Abstract: This study evaluated the stress distribution in the dentoalveolar and palatal bone structures during maxillary expansion in a 17-year-old male patient with bilateral cleft lip and palate (BCLP) using expanders with dental (HYRAX) and skeletal anchorage (MARPE). For the generation of the specific finite element models, cone-beam computed tomography was used, and the DICOM files were exported to Mimics 3-Matic (Materialise) and Patran (MSC Software) software. Three specific three-dimensional models were generated: A) HYRAX: conventional four-banded hyrax screw (9 mm); B) MARPE-DS: 3 miniscrews (1.8 mm diameter - 5.4 mm length) and four-banded dental anchorage; and C) MARPE-NoDS: 3 miniscrews without dental anchorage. Maxillary expansion was simulated by activating the expanders transversely 1 mm on the "X" axis. HYRAX resulted in higher levels of deformation predominantly in the dentoalveolar region. MARPE-DS showed stress in the dentoalveolar region and mainly in the center of the palatal region, at approximately 4,000 με. MARPE-NoDS exhibited evident stress only in the palatal region. High stress levels in the root anchoring teeth were observed for HYRAX and MARPE-DS. In contrast, MARPE-NoDS cause stress on the tooth structure. The stress distribution from the expanders used in the BLCP showed asymmetric expansive behavior. During the initial activation phase of expansion, the HYRAX and MARPE-DS models produced similarly high strain at the dentoalveolar structures and upper posterior teeth displacement. The MARPE-NoDS model showed restricted strain on the palate.

The short- and long-term changes of upper airway and alar in nongrowing patients treated with Mini-Implant Assisted Rapid Palatal Expansion (MARPE): a systematic review and meta-analysis.

OBJECTIVE: This study aims to assess the short- and long-term changes in the upper airway and alar width after mini-implant -assisted rapid palatal expansion (MARPE) in nongrowing patients. METHODS: Five electronic databases (PubMed, Scopus, Embase, Web of Science, and Cochrane Library) were searched up to 2 August, 2023 based on the PICOS principles. The main outcomes were classified into three groups: 1) nasal cavity changes, 2) upper airway changes and 3) alar changes. The mean difference (MD) and 95% confidence intervals (CI) were used to assess these changes. Heterogeneity tests, subgroup analyses, sensitivity analyses, and publication bias were also analyzed. RESULT: Overall, 22 articles were included for data analysis. Nasal cavity width (WMD: 2.05 mm; 95% CI: 1.10, 3.00) and nasal floor width (WMD: 2.13 mm; 95% CI: 1.16, 3.11) increased significantly. While palatopharyngeal volume (WMD: 0.29 cm3, 95% CI: -0.44, 1.01), glossopharyngeal volume (WMD: 0.30 cm3, 95% CI: -0.29, 0.89) and hypopharyngeal volume (WMD: -0.90 cm3; 95% CI: -1.86, 0.06) remained unchanged, nasal cavity volume (WMD: 1.24 cm3, 95% CI: 0.68, 1.81), nasopharyngeal volume (MD: 0.75 cm3, 95% CI: 0.44, 1.06), oropharyngeal volume (WMD: 0.61 cm3, 95% CI: 0.35, 0.87), and total volume of the upper airway (WMD: 1.67 cm3, 95% CI: 0.68, 2.66) increased significantly. Alar width (WMD: 1.47 mm; 95% CI: 0.40, 2.55) and alar base width (WMD: 1.54 mm; 95% CI: 1.21, 1.87) also increased. CONCLUSION: MARPE can increase nasal cavity width, nasal cavity volume, nasopharyngeal volume and oropharyngeal volume for nongrowing patients, but has no significant effect on hypopharyngeal volume. In addition, the alar width also increased. However, the studies included in this meta-analysis were mainly retrospective, nonrandomized and small in number, so the findings should be interpreted with caution and high-quality RCTs need to be studied.

Vertical and sagittal changes produced by an expander with differential opening and fan-type expander: A post-hoc analysis of a randomised controlled trial.

OBJECTIVE: To compare the sagittal and vertical cephalometric effects in participants treated with an expander with differential opening (EDO) versus the fan-type expander (FE). DESIGN: Two-arm parallel randomised clinical trial (RCT). METHODS: This study comprised cone-beam computed tomography-derived cephalometric images from 48 participants from a RCT. The sample was randomly allocated into two groups. The study was single-blinded. In total, 24 participants were treated with rapid maxillary expansion (RME) using EDO and 24 participants underwent RME using FE. The primary outcomes were the dentoskeletal vertical changes produced by RME. The secondary outcomes were the dentoskeletal sagittal changes. A cephalometric analysis was performed before treatment and 1 or 6 months after the active phase of RME using Dolphin Imaging Software. Intergroup comparisons of interphase changes were performed using the t-test and Mann-Whitney U test (P < 0.05). RESULTS: The final sample comprised 24 patients (11 men, 13 women; mean age = 7.6 ± 0.9 years) in the EDO group and 24 patients (10 men, 14 women; mean age = 7.8 ± 0.9 years) in the FE group. Both expanders produced a similar clockwise rotation of the mandible (FMA; mean difference [MD] = 0.09°, 95% confidence interval [CI] = -1.01 to 0.84). In the FE group, a greater increase of the SNA angle was observed after expansion compared to the EDO group (MD = 1.04°, 95% CI = -1.90 to -1.58). A greater palatal torque of maxillary incisors was observed in the FE group (MD = 1.32°, 95% CI = 0.05-2.56). Of the participants, 54% reported a little discomfort during the active phase of treatment and 46% of the participants did not report any discomfort. CONCLUSION: Both expanders produced similar vertical cephalometric changes. FEs caused slightly more maxillary anterior displacement after expansion with a compensatory palatal torque of the maxillary incisors compared to the EDOs. However, the amount of sagittal difference was not clinically relevant. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov, under the identifier NCT03705871.

Stress distribution and displacement with four different types of MARPE on craniofacial complex: A three-dimensional finite element analysis.

BACKGROUND: Various designs of mini-implants assisted rapid palatal expander (MARPE) appliances can impact treatment effectiveness through their biomechanical effects. The purpose of the study was to study the stress distribution and displacement with four different designs of the MARPE appliance on the craniofacial complex. METHODS: A 3D finite element model of the craniofacial complex was created from CBCT DICOM data, comprising four distinct groups. Each group consisted of one 4-hole expansion screw positioned between the second premolar and first molar in all models. Group 1 used four single-cortical mini-implants (1.5×8mm) engaging only the palatal cortex. Group 2 employed four mini-implants (1.5×11mm) engaging both the palatal and nasal cortices. Group 3 had monocortical implants on the palatal slopes, while Group 4 was similar to group 3 with implants in the acrylic wings. Comparisons between groups were made for anchorage (groups 1 and 2), mini-implant position (groups 1 and 3) and surface effect (groups 3 and 4). Von Mises stresses and displacements at various skeletal and dental points were evaluated using ANSYS software. RESULTS: The highest stresses were observed in the maxillary, pterygoid and zygomatic bones, as well as in the mid- palatal suture in all four groups. Downward and forward rotation of the craniofacial complex was noted. Group 2 showed greater skeletal expansion than group 1. Among groups 1 and 3, group 3 showed a better stress distribution. Group 4 showed less dentoalveolar rotation than group 3. CONCLUSIONS: The MARPE appliances had an impact on the craniofacial complex with stresses on the mid-palatal suture, maxillary bone, pterygoid bones and anterior teeth. Clockwise rotation of the maxilla, zygomatic bones and dentition was noted, while the pterygoid bones and pterygoid suture were displaced backwards. MARPE with bicortical anchorage produces better skeletal expansion. Placing implants on the palatal slopes with acrylic wings results in better skeletal expansion with less clockwise rotation of the dentition.

Randomized clinical trial of surgically assisted rapid maxillary expansion with two and three segments for nasal breathing.

OBJECTIVES: To evaluate surgically assisted rapid maxillary expansion (SARME), with osteotomies separating the maxilla into two segments (SARME-2S) and three segments (SARME-3S), on obstruction symptoms and nasal cavity dimensions in patients with maxillary transverse skeletal deficiency (MTSD). MATERIALS AND METHODS: Sixteen patients with MTSD of 7 mm or above were evaluated in each group, for a total of 32 patients. All patients were evaluated pre- and postoperatively up to 10 months after the expander activations. The minimum cross-sectional area (MCA) and the volume of the nasal cavities were identified by acoustic rhinometry. The Nasal Obstruction Symptom Evaluation (NOSE) scale questionnaire was applied. The palate surface area (PSA) was measured, via digitized maxillary models, as a criterion for comparison with the other variables studied. RESULTS: There was no difference between the groups (p = 0.370) and was verified a significant increase in PSA postoperatively. MCA showed a small increase without statistical significance, and together with the volume of the nasal cavities remained constant during the study. NOSE scale scores decreased significantly in the postoperative periods, implying a decrease in nasal obstruction symptoms in both groups. CONCLUSIONS: SARME with two and three segments show similar results, and both may improve nasal obstruction symptoms when present in patients with MTSD. CLINICAL RELEVANCE: SARME, regardless of the chosen surgical technique, should follow the recommendation to correct just the MTSD. While an improvement in nasal breathing is expected, this must be understood as likely, but not certain.

Comparison of nasal cavity changes between the expander with differential opening and the fan-type expander: a secondary data analysis from an RCT.

INTRODUCTION: The aim of this study was to compare the nasal cavity skeletal changes between the expander with differential opening (EDO) and the fan-type expander (FE). METHODS: This study was a secondary analysis of a previous randomized clinical trial. Forty-eight patients with posterior crossbite were randomly allocated into two study groups. Twenty-four patients (11 male, 13 female) with a mean initial age of 7.6 ± 0.9 years were treated with rapid maxillary expansion (RME) using the EDO. Twenty-four patients (10 male, 14 female) with a mean initial age of 7.8 ± 0.9 years were treated with the FE. Cone-beam computed tomography (CBCT) was performed before treatment and 1 to 6 months after the active phase of RME. Using frontal CBCT slices passing at the level of maxillary permanent first molars and maxillary deciduous canines, the width of the nasal cavity was measured in the lower, middle and upper thirds. Nasal cavity height was also evaluated in both slices. Intergroup comparisons of interphase changes were performed using t or Mann-Whitney tests (P < 0.05). RESULTS: The two groups were similar regarding baseline data. EDO showed a greater transverse increase in the lower third of the nasal cavity in both canine (P = 0.007) and molar regions (P < 0.001). No intergroup difference was observed for changes in middle and upper widths and height of the nasal cavity. CONCLUSIONS: Both expanders are effective in promoting an increase of the nasal cavity skeletal dimensions. The expander with differential opening produced a greater transverse increase in the lower third of the nasal cavity compared to the fan-type expander, both at the anterior and posterior regions of the maxilla. CLINICAL RELEVANCE: EDO might be more beneficial to pediatric patients with oral breathing and obstructive sleep apnea compared to FE.

F-quad helix for simultaneous maxillary expansion and tooth alignment in patients with unilateral cleft lip and/or palate.

Illustrating F-quad helix with extension arms that simultaneously expand maxillary arch and rotate its central incisor adjacent to the alveolar cleft while aligning palatally ectopic canines. Incisor rotation occurred before alveolar grafting, while canine traction was performed after alveolar grafting. The construction of this appliance is shown in detail.