Relationship Between Circummaxillary and Intramaxillary Suture Densities and Skeletal Effects of Rapid Maxillary Expansion.

Objective: This retrospective clinical study aimed to evaluate the maturation of intramaxillary and circummaxillary suture systems and cervical vertebral maturation as predictors of the skeletal response achieved by rapid maxillary expansion (RME). Methods: A Digital Imaging and Communication in Medicine dataset of 20 patients (mean age: 15.55 years) prior (T0) and after (T1: 3.5±0.5 months) to RME were retrieved from the archive and analyzed. Bone density values of midpalatal suture (MPS), zygomaticomaxillary suture (ZMS), zygomaticotemporal suture (ZTS), pterygopalatine suture (PPS), and transverse palatine suture (TPS) were measured. The cervical vertebral maturational stages (CVS) were examined. The linear distances between the most lateral points of the piriform apertures were measured as the anterior reference, and the medial margins of the greater palatine foramina on the axial slice were chosen as the posterior reference. The difference at T1-T0 was calculated as the skeletal response to RME at anterior and posterior skeletal references. Spearman's rho rank and Kruskal-Wallis tests were used. Results: Mean density values of ZMS, PPS, ZTS, TPS, MPS-Anterior, and MPS-Posterior were 922.81, 807.44, 753.83, 640.77, 661.13, and 604.59 HU, respectively. Mean linear changes in anterior and posterior skeletal expansion were 2.93±1.78 and 1.93±2.52 mm. There was no significant relationship between maturation indicators and skeletal response. Significant relationships were found between CVS and MPS density and CVS and circummaxillary suture average density (p≤0.05). Conclusion: Sutural density showed significant variations among CVSs. Although there was no correlation between skeletal response and density measurements, sutural density was found to be a promising indicator for future studies.

Evaluation of Mandibular Projection in Class II Division 2 Subjects Following Orthodontic Treatment Using Clear Aligners.

AIM: The purpose of this study was to evaluate the mandibular growth and/or projection following maxillary incisor proclination, overbite correction, and maxillary dentoalveolar expansion without the use of any class II mechanics, in growing class II division 2 patients treated with clear aligners. MATERIALS AND METHODS: Before and after treatment cone-beam computed tomographic (CBCT) generated lateral and posteroanterior cephalograms of thirty-two patients with skeletal class II division 2, 16 in the treatment group and 16 in the untreated group, were reviewed to evaluate treatment-related changes. Upper incisors were proclined and protruded, as well as upper arch expansion and overbite correction were performed as part of their regular treatment. Cephalometric analysis was performed to evaluate skeletal and dental changes. Unpaired statistical t-tests were performed to determine if significant skeletal class II correction was achieved in the treatment group. RESULTS: In the treatment group, after treatment, the upper incisors became more proclined and protruded, and the inter-molar width increased while the overbite was reduced compared to the control group. An increase in skeletal mandibular growth and forward projection was also observed, thus contributing to an improvement of the sagittal skeletal relationship as evidenced by ANB and Wits values compared to the control group. CONCLUSION: A combination of upper incisor proclination, correction of deep overbite, and maxillary dentoalveolar expansion using clear aligners appears to contribute to an improvement of the skeletal class II relationship in growing patients with class II division 2. CLINICAL SIGNIFICANCE: This study shows that unlocking the mandible by correcting a deep overbite, proclining upper incisors, and expanding the upper arch in growing class II division 2 patients can improve skeletal class II using clear aligners. How to cite this article: Mirzasoleiman P, El-Bialy T, Wiltshire WA, et al. Evaluation of Mandibular Projection in Class II Division 2 Subjects Following Orthodontic Treatment Using Clear Aligners. J Contemp Dent Pract 2024;25(4):295-302.

Predictability of expansion movements performed by clear aligners in mixed dentition in both arches: a retrospective study on digital casts.

BACKGROUND: to evaluate the predictability of expansion achieved in patients in early mixed dentition treated with Clear Aligners (CA), analyzing the efficiency of the expansion at the end of the first set of aligners and at the end of the therapy in the upper and lower arch. METHODS: 36 patients (20 F, 16 M; mean age 8.3 ± 1.5 years) were selected retrospectively from the Department of Orthodontics of the Hospital of Rome "Tor Vergata". All subjects were treated with CA with no other auxiliaries than attachments. For each patient a standardized sequential expansion protocol was planned for both arches. Digital dental casts were created at three observation periods from an intraoral scanner: prior to treatment (T0), at the end of the first set of aligners (T1), at the end of treatment (T2). The 3D models in planned position determined by the first Clincheck (CC) were obtained for comparison with T1 and T2. Six linear transversal measurements were used to evaluate the dimensional changes and the predictability of expansion movements, comparing T1-CC and T2-CC. RESULTS: a statistically significant increase within the pre-treatment and the final outcomes for all the variables examined was found. In the upper arch, the greatest level of predictability was detected at the level of the first (46.44%) and second deciduous molar width (44.95%) at T1. The analysis of T2-CC changes showed a significant increase in the percentage of predictability of expansion at the level of the first permanent molars, at mesial (54.86%) and distal (58.92%) width. In the lower arch, a higher percentage of predictability than the upper arch was reported at T1-CC and T2-CC, with the greatest values at the level of second (T1-CC: 48.70%; T2-CC: 75.32%) and first deciduous molar width (T1-CC: 45.71%; T2-CC: 72.75%). CONCLUSIONS: CA can induce significant transversal increments. The predictability of expansion is variable, but it did not exceed the 50% during the first set of aligners. It was necessary to apply refinement set to achieve a good predictability for expansion of about 70%. The expansion in the lower arch was observed to be more predictable than in the upper arch.

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.

Three-dimensional assessment of the maxilla after modified surgically assisted rapid expansion: a retrospective study.

OBJECTIVE: This retrospective study aims to assess the three-dimensional dentoskeletal effects and median palatal suture opening pattern in patients undergoing modified surgically assisted maxillary rapid expansion (SARME) without pterygoid plate detachment. METHODS: Twenty-eight patients submitted to modified SARME between 2009 and 2016 were retrospectively evaluated through cone-beam computed tomography (CBCT). Dental and skeletal measurements were taken at three different operative periods (before the expansion - T0; at the end of the activation of the Hyrax device - T1; and six months after the immobilization of the device - T2). Statistical analyses, including ANOVA and Pearson's correlation coefficient, were performed using SPSS software. RESULTS: SARME demonstrated significant transverse maxillary expansion (with an average of 6.05 mm) with a greater impact in the anterior region. Dental measurements, including canine and molar distances, exhibited significant changes over the operative periods. Bone measurements (ANS and PNS) presented small but significant alterations, including a slight inferior displacement of ANS during device activation. The nasal floor width increased, followed by a width reduction after immobilization. The median palatal suture predominantly exhibited a Type II (V-shaped) opening. CONCLUSION: The modified SARME presented a transversal direction increase and a super-lower skeletal displacement, with the anterior region being more affected than the posterior region. There was no change in the anteroposterior direction of the maxilla. Additionally, there was an increase in the linear dental measurements and a decrease in the angular measurement, with a positive correlation between the amount of posterior bone expansion and molar expansion as a result of the treatment in the analyzed period.

Numerical study of the impact of osteotomies and distractor location in surgically assisted rapid palatal expansion for transverse maxillary deficiency.

INTRODUCTION: This paper employs finite element analysis to assess the biomechanical behavior of surgically assisted rapid palatal expansion (SARPE) with a bone-borne transpalatal distractor (TPD) by varying surgical parameters. MATERIAL AND METHODS: Nine models were constructed to scrutinize the effects of pterygomaxillary disjunction (PMD), lateral osteotomy positioning, and TPD placement on displacement profiles and Von Mises stresses. These models encompassed variations such as no, unilateral or bilateral PMD, asymmetrical lateral osteotomy, and five TPD locations. RESULTS: Performing a PMD reduces posterior resistance to transverse expansion, resulting in 10-20 % stress reduction around the maxillofacial complex. No significant changes in horizontal tipping were observed post-PMD. The asymmetric lateral osteotomy model exhibited larger displacements on the side with a more superiorly positioned osteotomy. Reduced stresses were observed at the maxillary body and medial pterygoid plate (superiorly), while increased stresses were observed at the medial (inferiorly) and lateral pterygoid plates. More posterior TPD placement facilitated more parallel expansion thus less horizontal tipping, albeit with increased vertical tipping. DISCUSSION: SARPE procedures (distractor and osteotomy positions) can be tailored based on desired outcomes. PMD reduces stress within the maxillofacial complex but doesn't significantly affect tipping. Higher lateral osteotomies lead to increased displacements, more posterior distractors to more parallel 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.

Clinical Insights Into Addressing Constricted Maxillary Arch in Angle's Class II Malocclusion: A Case Report.

The transverse dimension, often overlooked in orthodontics, plays a crucial role in malocclusions, affecting not only occlusion in that dimension but also sagittal and vertical dimensions. Posterior crossbites, indicative of transverse maxillary issues, are commonly addressed through palatal expansion. This case report explores the clinical insights into addressing a constricted maxillary arch in Angle's Class II malocclusion using a nickel-titanium (NiTi) expander. The NiTi expander provides constant and optimal expansion forces by incorporating a temperature-activated NiTi alloy. A 16-year-old male with irregularly placed teeth, high palatal vault, and posterior crossbite underwent treatment involving NiTi expander usage for maxillary expansion. The case presentation details the patient's journey, starting with upper arch bonding and expansion, then lower arch bonding, and concluding with complete leveling and alignment without extractions. The presented case demonstrates successful correction of a constricted maxillary arch, specifically in the canine and molar regions, utilizing the NiTi expander. The observed increase in intermolar width aligns with previous studies, showcasing the effectiveness of slow maxillary expansion. This article contributes valuable clinical insights into addressing transverse maxillary issues, emphasizing the importance of careful consideration in choosing the appropriate expansion method for optimal results.

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.

Spontaneous Mandibular Dentoalveolar Changes after Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander-A Systematic Review.

BACKGROUND: This systematic review aims to analyze the spontaneous dentoalveolar changes in the mandibular arch after maxillary expansion in growing patients obtained with different expansion protocols: Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander. METHODS: The study adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Eligibility criteria were established in the PICO format, involving patients who underwent slow, rapid, or leaf maxillary expansion during the mixed or early permanent dentitions. A comprehensive search of electronic databases and manual searches was conducted up to December 2023. The outcome measures included inter-mandibular first permanent molar width, inter-deciduous molar and canine width, arch perimeter, and arch length; both short- and long-term results were considered. The articles that met the inclusion criteria were included in this systematic review and were qualitatively evaluated using a methodological quality scoring system with a 13-point scale. To assess the inter-examiner agreement concerning the article selection and the qualitative assessment of the included studies, Kappa statistics were computed. RESULTS: A total of 1184 articles were identified through electronic and manual searches. After the removal of duplicates and the initial examination of the titles and abstracts, 57 articles were considered for the full text analysis, and according to the eligibility and exclusion criteria, 22 studies were finally selected, composed of 8 randomized controlled trials (RCTs) and 14 retrospective/case-control studies. The qualitative assessment of the included studies showed the following scores: 6 papers have high research quality, 5 have moderate quality, and 11 have low quality. SME demonstrated negligible mandibular changes, with less than 1 mm variation on average (range 0.46-2.00 mm) in the selected parameters and relapses observed in the long term. RME induced more significant increases, particularly in intermolar width greater than 1 mm, which ranged between 0.93 and 3.3 mm, and good stability over the long term. Leaf Expander exhibited promising short-term lower intermolar width increases greater than 1 mm and ranged from 0.5 to 1.69 mm, but long-term stability was not thoroughly evaluated. CONCLUSIONS: SME results in negligible short- and long-term effects, while RME, especially with Haas-type appliances, exhibits significant intermolar width increases that remain stable over the years. Leaf Expander shows short-term lower intermolar width increases, requiring further investigation into long-term stability.

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

OBJECTIVES: The 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. METHODS: This 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. RESULTS: All 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. CONCLUSIONS: Twelve 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 SIGNIFICANCE: From the clinical perspective, the results of the present study encourage caution when considering the therapeutic effects of RME on airways dimensions.

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.

Does Miniscrew-Assisted Rapid Palatal Expansion Influence Upper Airway in Adult Patients? A Scoping Review.

(1) Objective: This scoping review evaluates the effects of miniscrew-assisted rapid palatal expansion (MARPE) on different regions of the upper airway in adult patients and investigates various methods of measurement. (2) Methods: The search encompassed Pubmed, Cochrane Library, Scopus and Web of Science. This review was conducted following the PRISMA_ScR guidelines, and the inclusion criteria for examined studies were chosen in accordance with the PICOS framework. (3) Results: Seven studies were included in this review, comprising four retrospective studies, one prospective and two case reports. All studies involved the use of Cone Beam Computed Tomography (CBCT) for measurements of the areas of interest. The percentage of increase in the volume of the nasal cavity varied between 31% and 9.9%, depending on the study. Volumetric variations in the nasopharynx were reported as increases between T0 (before expansion) and T1 (immediately after expansion) of 6.4%, 20.7% and 14.1%. All studies considered T0 before expansion and T1 immediately after expansion. Only one study evaluated remote follow-up to assess if the results were maintained after one year. (4) Conclusions: MARPE appears to lead to a statistically significant increase in the upper airway, especially in the nasal cavity and nasopharynx immediately after expansion. However, further prospective and retrospective trails with long-term controls are required to verify the effects of MARPE on the upper airway.

The Complexity of Skeletal Transverse Dimension: From Diagnosis, Management, and Treatment Strategies to the Application of Collaborative Cross (CC) Mouse Model.

This study investigates the significance of skeletal transverse dimension (STD) in orthodontic therapy and its impact on occlusal relationships. The primary goal is to enhance understanding and promote the integration of transverse skeletal diagnostics into routine orthodontic assessments. To achieve this aim, the study employs a comprehensive approach, utilizing model analysis, clinical assessments, radiographic measurements, and occlusograms. The initial step involves a meticulous assessment of deficiencies in the maxilla, mainly focusing on transverse dimension issues. Various successful diagnostic methods are employed to ascertain the type and presence of these deficiencies. Furthermore, the study compares surgically assisted maxillary expansion (SARME) and orthopedic maxillary expansion (OME) in addressing skeletal transverse issues. Stability assessments and efficacy analyses are conducted to provide valuable insights into the superiority of SARME over OME. The findings reveal that proper evaluation of STD is crucial in orthodontic diagnosis, as overlooking transverse dimension issues can lead to complications such as increased masticatory muscle activity, occlusal interferences, and an elevated risk of gingival recession. Surgically assisted maxillary expansion emerges as a more stable solution than orthopedic methods. In conclusion, incorporating skeletal transverse diagnostics into routine orthodontic assessments is imperative for achieving optimal occlusal relationships and minimizing negative consequences on dentition, periodontium, and joints. The study emphasizes the significance of accurate three-dimensional assessments and recommends the consideration of SARME over OME for addressing skeletal transverse deficiencies. Finally, the Collaborative Cross (CC) mouse model is also a novel mouse model for studying complex traits. Exploring the Collaborative Cross mouse model opens avenues for future research, promising further insights into transverse skeletal issues in orthodontics.

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.

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.

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.

Comparison of Mechanical Behavior of Clear Aligner and Rapid Palatal Expander on Transverse Plane: An In Vitro Study.

(1) Background: This study aims to investigate, within a controlled laboratory environment, the magnitude of the transversal load and the force decay over time produced by clear aligners in comparison to a Rapid Palatal Expander (RPE). (2) Methods: Resin models of a dental maxillary arch, additively manufactured from an intraoral scan, were inserted in a testing machine with uniaxial load cells to measure the force trend over time expressed by RPE and clear aligners. The mechanical load was recorded during a certain timeframe for both appliances. (3) Results: The force expressed by the RPE ranged from 30 to 50 N for each activation, decreasing with a nonlinear pattern over time. The force expressed by the clear aligner ranged from 3 to 5 N, decreasing with a linear pattern over time. In contrast, the force generated by the clear aligner fell within the range of 3 to 5 N, showing a linear reduction in force magnitude over the observed period of time. (4) Conclusions: The RPE exerted a force magnitude approximately ten times greater than that generated by clear aligners. Nevertheless, it is essential to acknowledge that the oral environment can significantly influence these results. These limitations underscore the need for caution when applying these findings to clinical settings.

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.

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.