Skeletal and alveolar changes in conventional rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE): a prospective randomized clinical trial using low-dose CBCT

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.

Slow maxillary expansion in adult patient with Hyrax expander: A case report

Slow maxillary expansion is a technique used to achieve correction of maxillary transverse deficiency or posterior crossbite in patients where the midpalatal suture has closed. This is mostly achieved by buccal tipping of maxillary posterior teeth. The aim of this case report is to discuss the orthodontic treatment of a 20-year-old patient with bilateral posterior crossbite. The patient had moderate maxillary crowding and severe mandibular crowding, crossbites bilaterally on his posterior teeth, and maxillary lateral incisors. The patient had thin gingival biotype with gingival recession on the mandibular right canine. Orthodontic treatment was done with full fixed appliances, and extraction of a mandibular right lateral incisor. This case report shows that slow maxillary expansion can be used in an adult to achieve the objectives set by both the orthodontist and patient while also considering treatment modalities most agreeable to the patient. Key words:Orthodontic treatment, slow maxillary expansion, maxillary expansion, RPE, Hyrax expander, case report.

Prediction of midpalatal suture maturation stage based on transfer learning and enhanced vision transformer

BACKGROUND

Maxillary expansion is an important treatment method for maxillary transverse hypoplasia. Different methods of maxillary expansion should be carried out depending on the midpalatal suture maturation levels, and the diagnosis was validated by palatal plane cone beam computed tomography (CBCT) images by orthodontists, while such a method suffered from low efficiency and strong subjectivity. This study develops and evaluates an enhanced vision transformer (ViT) to automatically classify CBCT images of midpalatal sutures with different maturation stages.

METHODS

In recent years, the use of convolutional neural network (CNN) to classify images of midpalatal suture with different maturation stages has brought positive significance to the decision of the clinical maxillary expansion method. However, CNN cannot adequately learn the long-distance dependencies between images and features, which are also required for global recognition of midpalatal suture CBCT images. The Self-Attention of ViT has the function of capturing the relationship between long-distance pixels of the image. However, it lacks the inductive bias of CNN and needs more data training. To solve this problem, a CNN-enhanced ViT model based on transfer learning is proposed to classify midpalatal suture CBCT images. In this study, 2518 CBCT images of the palate plane are collected, and the images are divided into 1259 images as the training set, 506 images as the verification set, and 753 images as the test set. After the training set image preprocessing, the CNN-enhanced ViT model is trained and adjusted, and the generalization ability of the model is tested on the test set.

RESULTS

The classification accuracy of our proposed ViT model is 95.75%, and its Macro-averaging Area under the receiver operating characteristic Curve (AUC) and Micro-averaging AUC are 97.89% and 98.36% respectively on our data test set. The classification accuracy of the best performing CNN model EfficientnetV2_S was 93.76% on our data test set. The classification accuracy of the clinician is 89.10% on our data test set.

CONCLUSIONS

The experimental results show that this method can effectively complete CBCT images classification of midpalatal suture maturation stages, and the performance is better than a clinician. Therefore, the model can provide a valuable reference for orthodontists and assist them in making correct a diagnosis.

Mechanically induced M2 macrophages are involved in bone remodeling of the midpalatal suture during palatal expansion

BACKGROUND

Palatal expansion is a common way of treating maxillary transverse deficiency. Under mechanical force, the midpalatal suture is expanded, causing local immune responses. This study aimed to determine whether macrophages participate in bone remodeling of the midpalatal suture during palatal expansion and the effects on bone remodeling.

METHODS

Palatal expansion model and macrophage depletion model were established. Micro-CT, histological staining, and immunohistochemical staining were used to investigate the changes in the number and phenotype of macrophages during palatal expansion as well as the effects on bone remodeling of the midpalatal suture. Additionally, the effect of mechanically induced M2 macrophages on palatal osteoblasts was also elucidated in vitro.

RESULTS

The number of macrophages increased significantly and polarized toward M2 phenotype with the increase of the expansion time, which was consistent with the trend of bone remodeling. After macrophage depletion, the function of osteoblasts and bone formation at the midpalatal suture were impaired during palatal expansion. In vitro, conditioned medium derived from M2 macrophages facilitated osteogenic differentiation of osteoblasts and decreased the RANKL/OPG ratio.

CONCLUSIONS

Macrophages through polarizing toward M2 phenotype participated in midpalatal suture bone remodeling during palatal expansion, which may provide a new idea for promoting bone remodeling from the perspective of regulating macrophage polarization.

Short- and long-term effects of conventional and miniscrew-assisted rapid palatal expansion on hard tissues using voxel-based superimposition of serial cone-beam computed tomography scans

INTRODUCTION

The objective of this study was to evaluate the short-term and long-term hard-tissue changes with miniscrew-assisted rapid palatal expansion (MARPE) and rapid palatal expansion (RPE) compared with a matched control group with voxel-based superimposition using 3-dimensional cone-beam computed tomography (CBCT) scans.

METHODS

A total of 180 CBCT scans were analyzed for 60 patients with a mean age of 13.9 years at 3 time points: pretreatment (T1), postexpansion (T2), and posttreatment (T3). Patients were divided into 3 groups: MARPE, RPE, and controls. Voxel-based superimposition was performed for CBCTs from T1 to T2 and T1 to T3 using the anterior cranial base as a reference. The hard-tissue surfaces were extracted after the superimposition procedure. Nine landmarks were analyzed: nasion, A-point, pogonion, left and right alar bases, zygoma, and gonion. Within-group changes were analyzed using linear mixed-effects models, including a random intercept per subject and the mixed effect of time (T1, T2, or T3) with test P values adjusted for multiple testing using Tukey's method. Between-group changes were analyzed using linear mixed-effects models, including a random intercept per subject and the mixed effects of time, group, and group × time interaction with P values adjusted for multiple testing using the Benjamin-Hochberg false discovery rate method.

RESULTS

In the short term, both MARPE and RPE led to a significant downward movement of the right gonion and lateral movement of the right alar base compared with controls at T2 (P <0.05). In addition, MARPE led to a significant downward movement of pogonion and left gonion. RPE led to a significant downward movement of the A-point and lateral movement of the left alar base compared with controls at T2 (P <0.05). However, in the long-term, no changes were observed between the groups at T3.

CONCLUSIONS

There were significant differences in pogonion, alar base, and gonion between MARPE, RPE, and control groups in the short term. However, all the hard-tissue changes were transient, as there were no differences between the 3 groups in the long term.

Combined distalization and lingual cortex remodeling during mandibular growth for facial profile improvement: a case report

Borderline crowding poses a challenge in deciding whether or not to prescribe premolar extraction. This case report describes the two-phase nonextraction orthodontic treatment of an 11-year-old girl with a hyperdivergent skeletal Class I pattern exhibiting anterior crowding and moderate lip protrusion. The initial phase of treatment included maxillary and mandibular expansion to correct the transverse discrepancy as an early intervention. Subsequently, comprehensive treatment was initiated at the age of 13 years, with fully erupted permanent second molars and growth potential remaining. Phase II treatment involved a second round of maxillary expansion, followed by simultaneous bimaxillary total arch intrusive distalization, using interradicular, temporary skeletal anchorage devices to correct dental crowding and improve the facial profile. Although the limited retromolar space posed a challenge to mandibular tooth distalization, gradual bone remodeling was observed in the lingual cortex of the mandibular body, enabling sufficient orthodontic tooth movement without noticeable side effects. After 4 years 3 months of treatment, her dental crowding was relieved, with significant improvement in the facial profile and proper occlusion. The treatment outcomes remained stable 2 years 4 months after retention.

Dentoperiodontal and skeletal changes induced by miniscrew-assisted rapid maxillary expansion (C-expander) treatment in adults: A retrospective clinical trial

INTRODUCTION

The objective of this study was to evaluate the dental periodontal and skeletal response to ≥5 mm of expansion width achieved by C-expander treatment with posterior miniscrews placed between the first and second molars in adults.

METHODS

A total of 28 patients aged 21.91 ± 3.20 years with maxillary transverse deficiency underwent C-expander treatment. Anterior miniscrews were positioned between the first and second premolars, whereas posterior miniscrews were positioned between the first and second molars. Cone-beam computed tomography records were obtained before expansion and 3 months after expansion. The dental periodontal and skeletal changes for all patients were recorded.

RESULTS

The C-expander treatment expanded the palatal suture with slight buccal alveolar bone inclination. An increase in the nasal cavity width and a greater increase in the maxillary base bone width were observed after maxillary expansion. The expansion at the posterior nasal spine (3.78 mm) was approximately 85.7% of that at the anterior nasal spine (4.41 mm). No significant buccal dehiscence occurred after expansion, whereas the mesiobuccal alveolar bone thickness of the first molars was decreased at the 8 mm level with respect to the cementoenamel junction. The first molar showed decreased inclination (right, -0.45°; left, -0.38°, P >0.05), whereas the expansion at the apical level was less than that at the crown level. Age and the skeletal/dental expansion ratio had no discernible relationship.

CONCLUSIONS

Miniscrew-assisted C-expander treatment can be effective for adults with maxillary transverse deficiency. Rearward placement of the miniscrews may create an approximately parallel expansion. Most maxillary expansion was derived from skeletal expansion with slight alveolar bone buccal inclination.

Skeletal and dentoalveolar modifications in adults with different sagittal facial patterns after personalized miniscrew-assisted rapid palatal expansion: A prospective cone-beam computed tomography study

INTRODUCTION

This study aimed to compare the skeletal and dental modifications in adults with different sagittal facial patterns by a personalized miniscrew-assisted rapid palatal expander (pMARPE).

METHODS

Forty subjects (aged 18-28 years; 15 females and 25 males) with maxillary transverse deficiency were assigned to 1 of 3 groups (Class I, II, and III relationship) on the basis of their sagittal facial patterns. Each patient was treated with an individually customized expander. A similar expansion protocol was used for all patients. Cone-beam computed tomography scans were obtained before and after expansion. One-way analysis of variance was used to analyze differences among 3 groups in skeletal, dentoalveolar, and periodontal changes (P <0.05).

RESULTS

The success rates of expansion were higher in patients with a Class I or II relationship than those with a Class III relationship. Patients with a Class I or II relationship had greater changes in the anterior nasal spine and maxillary basal bone widths. A more parallel sutural opening in the anteroposterior direction was seen in those with a Class II relationship. The tipping of the maxillary first molar increased, and the buccal alveolar bone thickness decreased in all groups after expansion, especially in patients with a Class III relationship.

CONCLUSIONS

The pMARPE effectively split the midpalatal suture among adults. However, midpalatal suture expansion was more difficult, and there were more dentoalveolar side effects and fewer orthopedic effects in patients with a Class III relationship than in those with Class I or II relationships.

Three-dimensional comparison of tooth-borne and tooth-bone-borne RME appliances: a randomized controlled trial with 5-year follow-up

OBJECTIVES

To compare the long-term skeletal effects of tooth-borne (TB) and tooth-bone-borne (TBB) rapid maxillary expansion in growing children, using 3D imaging.

MATERIALS AND METHODS

In total, 52 consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years (SD 1.3), or the TBB group, mean age 9.5 years (SD 1.2). Cone-beam computed tomography records and plaster models were taken before (T0), directly after (T1), 1 year after (T2), and 5 years after expansion (T3).

RANDOMIZATION

Participants were randomly allocated in blocks of different sizes, using the concealed allocation principle in a 1:1 ratio. The randomization list was also stratified by sex to ensure homogeneity between groups.

BLINDING

Due to clinical limitations, only the outcome assessors were blinded to the groups to which the patients were allocated.

RESULTS

At T1, the midpalatal suture at its anterior part showed a statistically significant difference between the groups with a mean of 0.6 mm (CI 0.2-1.1) more expansion in the TBB group (P < 0.01). This difference was also more evident in boys at T1 with a mean of 0.8 mm (CI 0.2-1.4) (P < 0.01). These differences, however, blotted out at T2 and T3. The nasal width also showed similar differences between the groups, with a significantly larger expansion in the TBB group by a mean of 0.7 mm (CI 0.1-1.4) (P = 0.03). This group difference in favour of the TBB group was maintained at T2 (1.6 mm) and T3 (2.1 mm) (P < 0.01 T2 and T3, respectively).

CONCLUSIONS

Skeletal expansion in the midpalatal suture was significantly higher in the TBB group; however, the magnitude of this expansion was around 0.6 mm more and may not be clinically significant. Skeletal expansion at the level of the nasal cavity was significantly higher in the TBB group. There were no differences between boys and girls with regard to skeletal expansion.

TRIAL REGISTRATION

This trial was not registered on any external sites.

Effects of novel microimplant-assisted rapid palatal expanders manufactured by 3-dimensional printing technology: A finite element study

INTRODUCTION

The expansion effects of several new microimplant-assisted rapid palatal expanders (MARPEs) manufactured by 3-dimensional printing technology were evaluated by finite element analysis (FEA). The aim was to identify a novel MARPE suitable for treating maxillary transverse deficiency.

METHODS

The finite element model was established using MIMICS software (version 19.0; Materialise, Leuven, Belgium). First, the appropriate microimplant insertion characteristics were identified via FEA, and several MARPEs with the above insertion patterns were manufactured by 3-dimensional printing technology. Then, the stress distribution and displacement prediction of the 4 MARPEs and hyrax expander (model E) were evaluated via FEA: bone-borne (model A), bone-tooth-borne (model B), bone-mucous-borne (model C), bone-tooth-mucous-borne (model D).

RESULTS

Monocortical microimplants perpendicular to the cortical bone on the coronal plane resulted in better expansion effects. Compared with a conventional hyrax expander, the orthopedic expansion of each of the 4 MARPEs was far larger, the parallelism was greater, and the posterior teeth tipping rate was lower. Among them, the expansion effects of models C and D were the best; the von Mises peak values on the surfaces of the microimplants were smaller than those of models A and B.

CONCLUSIONS

This study may demonstrate that the 4 MARPEs obtained more advantageous orthopedic expansion effects than a hyrax expander. Models C and D obtained better biomechanical effects and had better primary stability. Overall, model D is the recommended expander for treating maxillary transverse deficiency because its structure acts like an implant guide and is beneficial for the accurate insertion of the microimplant.

Rapid Maxillary Expansion on the Adolescent Patient: Systematic Review and Case Report

Aim: In the literature, many studies and articles are investigating new devices and approaches to achieve rapid palate expansion through the opening of the palatal suture, and evaluating the skeletal, dental, and soft tissue effects. The purpose of this review was to assess how palatal expansion is performed in adolescent patients with permanent dentition. Furthermore, it was reported as an example of successful orthodontic treatment of an 11-year-old female patient affected by maxillary skeletal transverse deficiency, in permanent dentition. Methods: A search of the literature was conducted on PubMed, Cochrane, Scopus, Embase, and Web of Science databases. Inclusion criteria were the year of publication between 2017 and 2022, patients aged 10 to 16 years in permanent dentition, with transversal discrepancy, treated with tooth-borne, bone-borne, hybrid palatal expanders. Results: A total of 619 articles were identified by the electronic search, and finally, a total of 16 papers were included in the qualitative analysis. Conclusions: From this study, it was assessed that MARPE is more predictable, and it determines a more significant expansion of the suture than the Hyrax expander, with fewer side effects.