Comparison of rapid versus slow maxillary expansion on patient-reported outcome measures in growing patients: a systematic review and meta-analysis

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.

Oropharyngeal swallowing hydrodynamics of thin and mildly thick liquids in an anatomically accurate throat-epiglottis model

Understanding the mechanisms underlying dysphagia is crucial in devising effective, etiology-centered interventions. However, current clinical assessment and treatment of dysphagia are still more symptom-focused due to our limited understanding of the sophisticated symptom-etiology associations causing swallowing disorders. This study aimed to elucidate the mechanisms giving rise to penetration flows into the laryngeal vestibule that results in aspirations with varying symptoms. Methods: Anatomically accurate, transparent throat models were prepared with a 45° down flapped epiglottis to simulate the instant of laryngeal closure during swallowing. Fluid bolus dynamics were visualized with fluorescent dye from lateral, rear, front, and endoscopic directions to capture key hydrodynamic features leading to aspiration. Three influencing factors, fluid consistency, liquid dispensing site, and dispensing speed, were systemically evaluated on their roles in liquid aspirations. Results: Three aspiration mechanisms were identified, with liquid bolus entering the airway through (a) the interarytenoid notch (notch overflow), (b) cuneiform tubercle recesses (recess overflow), and (c) off-edge flow underneath the epiglottis (off-edge capillary flow). Of the three factors considered, liquid viscosity has the most significant impact on aspiration rate, followed by the liquid dispensing site and the dispensing speed. Water had one order of magnitude higher aspiration risks than 1% w/v methyl cellulose solution, a mildly thick liquid. Anterior dispensing had higher chances for aspiration than posterior oropharyngeal dispensing for both liquids and dispensing speeds considered. The effects of dispending speed varied. A lower speed increased aspiration for anterior-dispensed liquids due to increased off-edge capillary flows, while it significantly reduced aspiration for posterior-dispensed liquids due to reduced notch overflows. Visualizing swallowing hydrodynamics from multiple orientations facilitates detailed site-specific inspections of aspiration mechanisms.

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.

Evolution, current status, and future trends of maxillary skeletal expansion: a bibliometric analysis

OBJECTIVES

The study aims to conduct a bibliometric analysis on maxillary skeletal expansion to elucidate the evolution and current status and predict future research hotspots and trends.

MATERIAL AND METHODS

A search was conducted in the Web of Science Core Collection at the University of Hong Kong's electronic library using the query "(TS = maxillary expansion) AND (TS = skeletal expansion)." The resulting literature data were imported into CiteSpace 6.2.R4 and VOS viewer software to analyze authorship, countries, institutions, keywords, etc. RESULTS: A total of 923 articles were analyzed. The research in this field has shown a steady growth, with a significant increase since 2019. The USA and Italy have played prominent roles in contributing to the publication volume and strengthening collaborative exchanges. Clustering labels provide directions for in-depth analysis of the literature.

CONCLUSIONS

(1) MARPE (miniscrew-assisted rapid palatal expansion) and SARME (surgically assisted rapid maxillary expansion) have gained widespread attention and become research hotspots due to their applicability in adults whose growth and development have ceased, while still producing favorable skeletal effects. (2) In addition to widening the maxillary arch, maxillary expansion techniques have shown significant effects on increasing nasal cavity width and volume. However, there is still controversy regarding whether they can effectively improve the deviated nasal septum. (3) Maxillary skeletal expansion techniques have been shown to increase upper airway volume and improve breathing, making them potentially valuable in the treatment of obstructive sleep apnea (OSA).

CLINICAL RELEVANCE

This study can provide cutting-edge clinical recommendations for healthcare professionals to better formulate clinical strategies.

Analysis of maxillary asymmetry before and after treatment of functional posterior cross-bite: a retrospective study using 3D imaging system and deviation analysis

BACKGROUND

Previous evidence would suggest that subjects affected by functional posterior cross-bite (FPXB) present an asymmetric morphology of the maxilla. However, no evidence is available concerning the morphology (symmetry/asymmetry) of the maxilla after treatment of FPXB. This study aimed to investigate the volumetric and morphological changes of the palate in FPXB subjects treated with maxillary expansion and to compare these data with an untreated control group. The study sample included 20 FPXB subjects (mean age 8.1 ± 0.9 years) who underwent maxillary expansion (MEG group) and 21 FPXB subjects (mean age 7.7 ± 1.2 years) as controls (CG group). Digital models were recorded at T0 (first observation) and T1 (12-18 months after first observation) and analyzed to assess palatal volume and symmetry. Deviation analysis and percentage matching calculation were also performed between original and mirrored palatal models for each patient. All data were statistically analyzed for intra-timing, inter-timing and inter-groups assessments.

RESULTS

At T0, the cross-bite side (CBS) was significantly smaller than non-cross-bite side (non-CBS) in both groups (p < 0.05). At T1, the CBS/non-CBS difference reduced significantly in the MEG group (p < 0.05) while slightly worsened in the CG, however without statistical significance (p > 0.05). The matching percentage of the palatal models improved significantly at T1 in the MEG group (T0 = 74.02% ± 9.8; T1 = 89.95% ± 7.12) (p < 0.05) while no significant differences were recorded in the CG (T0 = 76.36 ± 8.64; 72.18% ± 9.65) (p > 0.05).

LIMITATIONS

The small sample size and the retrospective design of the study represent two limitations that should be overcome with further clinical trials.

CONCLUSIONS

Subjects with FPXB present an asymmetric development of the maxillary vault that improves after reestablishment of normal occlusion following maxillary expansion.

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

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

Do patient-reported outcomes of miniscrew-supported maxillary expansion in adolescent patients differ between slow and rapid activation protocol?

DESIGN

Single-center randomized clinical trial with two parallel arms. The protocol of the study was approved by the institutional review board (IRB) of the Faculty of Dentistry, Alexandria University (IRB: 00010556-IORG: 0008839) and registered in Clinicaltrials.gov (identifier number: NCT04225637). Before the trial commencement, parents/legal guardians signed informed consents. The study complied with the CONSORT (Consolidated Standards of Reporting Trials).

CASE SELECTION

30 adolescent patients aged between 12 to 16 years with transversely deficient maxilla requiring skeletal maxillary expansion were recruited to be included in the study. Patients received miniscrew-supported Penn expanders and they were randomly allocated (ratio 1:1) into two groups based on the activation protocol; slow maxillary expansion (SME = turn every other day) or rapid maxillary expansion (RME = 2 turn/day).

DATA ANALYSIS

The patient-reported outcome measures were the following: pain, headache, pressure, dizziness, speech, chewing and swallowing difficulties, swallowing difficulty. The participants rated the reported outcomes using numeric rating scale (NRS) at 4 time points: t1 = before appliance insertion, t2 = after first activation, t3 = after 1 week of activation, and t4 = after last activation. Patients were advised not to use analgesics, and to contact their provider in case of severe pain. Descriptive measures and patient-reported outcomes at various time points were calculated. Comparisons between the two groups at each time point were assessed using Mann-Whitney U-test. Comparisons of time points in each group were assessed using the Friedman test and followed by post-hoc tests with Bonferroni correction.

RESULTS

6 patients were not included in the analysis for different reasons, allowing a total of 24 patients (12 patients in each group) to be analyzed. Mean ages of the patients in the SME and RME group were 14.30 ± 1.37 and 15.07 ± 1.59, respectively. Median scores were in the bottom quartiles of NRS for all reported outcomes. RME group reported significantly higher scores for all measured variables, with exception of headache and dizziness, which showed no statistical difference between the two group.

CONCLUSIONS

Mild to moderate discomfort and functional limitation is anticipated with the activation of miniscrew-anchored Penn expanders. Slow activation protocol provided a better overall patient experience when compared to a rapid activation protocol.