Tooth-borne vs bone-borne rapid maxillary expanders in late adolescence

Effects of different expansion appliances and surgical incisions on maxillary expansion: A finite element analysis

PURPOSE

This study aims to assess the impact of different surgical techniques and three expansion appliances on maxillary expansion in adults using finite element analysis (FEA), with a focus on maxillary displacement and stress on surrounding structures.

METHODS

Seven different FEA models were created to compare different surgical techniques and three different expansion appliances. Model I represented a bone-supported appliance without surgical assistance. Model II, Model III, and Model IV were surgically assisted rapid palatal expansion (SARPE) models without pterygomaxillary suture disjunction (PMD). Model V, Model VI, and Model VII were SARPE models with PMD.

RESULTS

The largest displacement at the anterior nasal spine (ANS) was recorded for Model II (2.95 mm). For the posterior nasal spine (PNS), the highest displacement was observed in Models V, VI, VII (2.50 mm), with the lowest in Model III (0.79 mm). Stress analysis revealed the highest stress in Model I, with models featuring PMD displaying nearly zero stress at all anatomical points, highlighting distinct expansion patterns and stress distributions between models with and without PMD.

CONCLUSION

SARPE models with PMD demonstrated a parallel expansion of the maxilla with minimal stress, while the miniscrew assisted rapid maxillary expansion (MARPE) model displayed transverse rotation. SARPE models without PMD exhibited a V-shaped expansion pattern. SARPE models with PMD represent an optimal approach for achieving uniform expansion and minimizing stress, with stress levels nearly negligible at all anatomical points in models with PMD.

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.

Tooth-Bone-Borne vs Bone-Borne Rapid Maxillary Expanders on Dentoskeletal Changes

Purpose

This study compared the insertion and thickness of the cortical bone, the parallelism of the midpalatal suture, and the skeletal transverse dimension using a microimplant-assisted rapid palatal expansion (MARPE) with those produced by bone-anchored maxillary expander (BAME) in adults.

Patients and Methods

The sample comprised 18 patients (mean age, 29.9±9.4 years) selected for the MARPE group and 18 (mean age 24.8±6.8 years) selected for the BAME group. Cone-Beam computed tomography scans taken just before and after the expansion.

Results

After treatment, there was a significant palatal depth decrease. In addition, maxillary and mandibular width were increased in both groups. Regarding the cortical bone insertion and cortical bone width, it is shown an increase in both groups but those changes are not significant. However, the anterior suture opening effect occurs more frequently in the BAME than in the MARPE device. There are no differences in the frequency of opening of the midpalatal suture in the cases treated with MARPE and BAME, in both cases the most frequent opening morphology is parallel, independently of midpalatal suture maturation.

Conclusion

There are no differences in the use of MARPE or BAME in the parallelism of the middle palatal suture, the cortical bone insertion, and thickness according to the maturation stages of the midpalatal suture but significantly increases the transverse dimensions of the maxillary skeleton.

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.

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

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.

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.

Analysis of Stress Distribution and Displacement Based on the Miniscrew Positions of the Palatal Slope Bone-borne Expander: A Finite Element Study

OBJECTIVES

 This study aimed to investigate the stress distribution pattern of the palatal slope bone-borne expander on the maxillary area according to a different anteroposterior position of anchored miniscrews using finite element analysis.

MATERIALS AND METHODS

 Nasomaxillary stereolithography files with three different anteroposterior anchored miniscrew positions of the palatal slope bone-borne expander were determined as model A, B, and C. Each model consists of four supported miniscrews. Model A: two anterior miniscrews were located between the maxillary canine and the first premolar, and two posteriors between the second premolar and the first molar. Model B: two anteriors were between the lateral incisor and the canine, and two posteriors were the same as in model A. Model C: two anteriors were the same as in model A, and two posteriors were distal to the first molar. One turn of expander screws was applied. Maximum principal stress, equivalent elastic strain, equivalent von Mises stress, and transverse displacement were evaluated.

RESULTS

 The maximum principal stress was mostly found at the bone-miniscrew interface. Model A exhibited an intersecting area of stress between the supported miniscrews. The highest value of principal stress was in model B, while model C showed a uniform distribution pattern. The elastic strain pattern was similar to the principal stress in all models. The highest value of equivalent von Mises stress was located on the expander screw. The largest amount of transverse displacement of teeth was in model A, while model C exhibited a more consistent transverse displacement than other models. Vertical displacement of posterior teeth was also noticed.

CONCLUSION

 Based on the result, it revealed that the various anteroposterior miniscrew placements of the palatal slope bone-borne expander had various patterns of stress distribution and resulted in various outcomes. It may be inferred that model A's miniscrew location was advantageous for obtaining expansion quantities, but model C's miniscrew position was advantageous for maintaining consistent biomechanics.

Effect of different palatal expanders with miniscrews in surgically assisted rapid palatal expansion: A non-linear finite element analysis

INTRODUCTION

Surgically assisted rapid palatal expansion (SARPE) has been the treatment of choice in subjects presenting skeletally mature sutures.

OBJECTIVE

The purpose of this study was to analyze stress distribution and displacement of the craniofacial and dentoalveolar structures resulting from three types of palatal expanders with surgical assistance using a non-linear finite element analysis.

MATERIAL AND METHODS

Three different palatal expanders were designed: Model-I (tooth-bone-borne type containing four miniscrews), Model-II (tooth-bone-borne type containing two miniscrews), and Model-III (bone-borne type containing four miniscrews). A Le Fort I osteotomy was performed, and a total of 5.0 mm palatal expansion was simulated. Nonlinear analysis (three theory) method (geometric nonlinear theory, nonlinear contact theory, and nonlinear material methods) was used to evaluate stress and displacement of several craniofacial and dentoalveolar structures.

RESULTS

Regardless of the maxillary expander device type, surgically assisted rapid palatal expansion produces greater anterior maxillary expansion than posterior (ANS ranged from 2.675 mm to 3.444 mm, and PNS ranged from 0.522 mm to 1.721 mm); Model-I showed more parallel midpalatal suture opening pattern - PNS/ANS equal to 54%. In regards to ANS, Model-II (1.159 mm) and Model-III (1.000 mm) presented larger downward displacement than Model-I (0.343 mm). PNS displaced anteriorly more than ANS for all devices; Model-III presented the largest amount of forward displacement for PNS (1.147 mm) and ANS (1.064 mm). All three type of expanders showed similar dental displacement, and minimal craniofacial sutures separation. As expected, different maxillary expander designs produce different primary areas and levels of stresses (the bone-borne expander presented minimal stress at the teeth and the tooth-bone-borne expander with two miniscrews presented the highest).

CONCLUSIONS

Based on this finite element method/finite element analysis, the results showed that different maxillary expander designs produce different primary areas and levels of stresses, minimal displacement of the craniofacial sutures, and different skeletal V-shape expansion.

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.

Comparison of the short-term effects of tooth-bone-borne and tooth-borne rapid maxillary expansion in older adolescents

PURPOSE

To compare the short-term effects of tooth-bone-borne and tooth-borne rapid maxillary expansion (RME) devices on dentofacial structures in older adolescents.

METHODS

The retrospective study reviewed pre- and posttreatment lateral and posteroanterior cephalometric images and orthodontic model records of patients who underwent maxillary expansion. Two groups were formed, in which the same upper jaw expansion protocol was applied with two different maxillary expansion devices: the first group consisted of 15 individuals treated with tooth-bone-borne (hybrid) RME (HRME; 9 girls and 6 boys; mean age, 16.9 ± 0.42 years) and the second group consisted of 15 individuals treated with tooth-borne (conventional) RME (CRME; 8 girls and 7 boys; mean age, 16.74 ± 0.54 years). Cephalometric and orthodontic model measurements were conducted on the records taken before and after treatment.

RESULTS

Significant skeletal and dental expansions were observed in both groups (p < 0.05). However, the increase in nasal width measurements in the HRME group (2.24 ± 0.61 mm) was significantly higher than the increase in the CRME group (1.12 ± 0.25 mm; p < 0.01). Buccal tipping of the premolars was significantly less in the HRME group (0.46 ± 0.35°) than in the CRME group (2.46 ± 0.63°; p < 0.01). The amount of tipping of the molars was higher in the HRME group (4.76 ± 0.88°) compared to the CRME group (2.9 ± 1.03°; p < 0.01).

CONCLUSION

Although the HRME device increase the nasal width in older adolescents to a greater extent, more dental side effects were seen at the maxillary first molars.

Responsiveness of three measurements in cone-beam computed tomography transverse analyses during both tooth-supported and mini-screw-assisted rapid maxillary expansion

OBJECTIVE

To evaluate the responsiveness of three cone-beam computed tomography (CBCT) transverse analyses (University of the Pennsylvania [UPenn] analysis, Boston University analysis and Yonsei University [YU] analysis).

MATERIALS AND METHODS

A consecutive cohort sample of patients was retrospectively reviewed for eligibility. CBCT records before treatment (T0) and immediately after maxillary expansion (T1) of 71 patients receiving tooth-supported rapid maxillary expansion (RME) and 57 patients receiving mini-screw-assisted RME (MARME) were finally analyzed. Responsiveness was assessed by comparing changes of measures (T1-T0) to mid-palatal suture opening distance (MSOD) at T1. Correlational responsiveness was assessed by Pearson correlation coefficient (r). Absolute agreement responsiveness was assessed by Bland-Altman analysis. A specialized intraclass correlation coefficient (ICC) was selected to assess responsiveness combining correlation and absolute agreement.

RESULTS

Changes of all three measures were moderately to strongly correlated to MSOD (r > 0.5). The highest correlation coefficient (0.79) was found between the YU analysis and MSOD. When exploring absolute agreement responsiveness, the smallest deviation (0.14 mm) was observed in the UPenn analysis. For ICC, the highest ICC value (0.63) was observed when the YU analysis was used. In addition, all three measurements were more responsive to MSOD in the MARME group than to those in RME group.

CONCLUSIONS

All three transverse measurements responded well to true changes of maxillary transverse deficiency during both tooth-supported and mini-screw-assisted RME. Deviations of responsive properties of these measurements from true skeletal changes were below a clinically meaningful level (1 mm).

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.

Skeletal and Dentoalveolar Changes in Growing Patients Treated with Rapid Maxillary Expansion Measured in 3D Cone-Beam Computed Tomography

The skeletal and dental effects of rapid maxillary expansion (RME) have been extensively studied, but high-quality research is still needed to determine the three-dimensional (3D) effects of RME. The aim of this study was to compare skeletal and dentoalveolar parameters through cone-beam computed tomography (CBCT) pre- (T1) and post-treatment (T2) with respect to RME. Twenty growing patients (mean age 10.7 years) were treated with a Hyrax-type expander. A 3D CBCT was performed at T1 and T2, measuring nasal width, maxillary width, palatal height, maxillary arch perimeter, angulation of the upper first molar, and intermolar width. The mean palatal suture opening was 2.85 ± 0.62 mm (p < 0.0001). Nasal width increased 1.28 ± 0.64 mm and maxillary width 2.79 ± 1.48 mm (p < 0.0001). In contrast, palatal height was reduced 0.65 ± 0.64 mm (p < 0.0001). Regarding arch perimeter, the radicular perimeter increased 2.89 ± 1.80 mm, while the coronal perimeter increased 3.42 ± 2.09 mm (p < 0.0001). Molar angulation increased 5.62 ± 3.20° for the right molar and 4.74 ± 2.22° for the left molar (p < 0.0001). Intermolar width increased 5.21 ± 1.55 mm (p < 0.0001). Treatment with Hyrax produced a significant opening in the mean palatal suture. Also, a significant increase in nasal width, maxillary width, arch perimeter, molar angulation, and intermolar width, and a decrease in palatal height, were observed.

Clinical and CT Scan Evaluation of Outcomes of Modified SARPE Using a Bone-Borne Hyrax Appliance in Unilateral Posterior Crossbite

Objective

The objective of this study was to evaluate, using clinical and computed tomography, outcomes of unilateral SARPE with a bone-borne hyrax appliance in case of unilateral crossbite and to assess the correlations between hyrax appliance opening and post-SARPE skeletal changes.

Materials and Methods

Two patients of unilateral crossbite underwent Unilateral SARPE and post-surgical expansion of maxilla using a bone-borne hyrax appliance. Computed tomography was used to make comparative linear and angular measurements of the anterior, intermediate, and posterior portions of the maxilla. The correlation between maxillary expansion and appliance opening was also investigated.

Results

Significant overall expansion was observed with maximum expansion in the anterior and inferior portions of the maxilla. The degree of appliance opening was significantly greater than that of the skeletal expansion. Comparative CAD measurements showed maximum increase in interdental width at the second premolar level.

Conclusion

The transverse expansion of the maxilla obtained with a bone-borne hyrax is less than uniform. The lack of linear correlation between appliance opening and skeletal expansion is attributable to multiple factors, including those related to the device, the surgical technique, and the craniofacial deformity itself.

Evaluation of expansion forces of five pure bone-borne maxillary expander designs anchored with orthodontic mini-implants: An in vitro study

AIM

This in vitro study investigates the limit of expansion forces and torque wrench forces developed by five skeletal bone expander designs (MICRO 2/4 expanders™) for clinical application.

MATERIAL AND METHODS

A total of 30 skeletal expanders were placed in artificial bone blocks and mechanically tested, simulating maxillary expansion. Differences in jackscrew (Dentaurum™ [D], Superscrew™ [S] and Powerscrew™ [P]), number of orthodontic mini-implants (OMIs; two or four) and their placement inclinations (parallel 0° or 10° inclination) form five designs (D4/10°, S4/0°, S4/10°, P4/10° and P2/10°). Expansion forces and torque wrench values were registered, and radiographs were made initially and after 4 mm of expansion. Stress-strain curves were obtained after successive activations and the statistical analysis was performed as appropriate.

RESULTS

Plastic deformations in the OMIs and jackscrew occurred around the activation numbers 11-13, with torque wrench values in the range of 500-700 cN. The maximum expansion forces in expanders with four OMIs varied from 93.0 (D4/10°) to 166.6 N (P4/10°) whereas two OMI expanders (P2/10°) registered forces of 79.4 N. Radiographs revealed during loads bending forces (S4/00°, S4/10°) with jackscrew and OMIs deformation in a convex shape, and shear forces (P4/10°, P2/10°) demonstrated only OMIs deformation in a concave shape, providing 15% more expansive force. The jackscrew D4/10° did not have any deformation, but its wire key did not allow reliable activations from activation number 10 and compared to S4/10° and P4/10°, these expanders provided greater expansion forces (P = 0.000 and P = 0.032, respectively).

CONCLUSION

The different results obtained in stability and expansion forces indicate that if the activations are carried out under extreme conditions, they may have clinical importance with deformations and non-working expansion mechanics. Jackscrew designs play an important role in expansive forces and expander stability. Torque wrench values can be used clinically as a tool to asses the expansion forces and to avoid deformations.

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.

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.

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.

Long-term efficacy and stability of miniscrew-assisted rapid palatal expansion in mid to late adolescents and adults: a systematic review and meta-analysis

BACKGROUND

The purpose of this study is to investigate the long-term efficacy and stability of Miniscrew-assisted Rapid Palatal Expansion (MARPE), including its primary outcomes, namely the nasomaxillary complex transverse skeletal and dental expansion, and related secondary outcomes.

METHODS

Electronic databases and manual literature searches, up to October 31, 2022, were performed. The eligibility criteria were the following: studies on patients with transverse maxillary deficiency treated with MARPE in adults and adolescents over 13.5 years of age.

RESULTS

Ultimately, twelve articles were included in the analysis, one prospective and eleven retrospective observational studies. Five studies showed a moderate risk of bias, while the remaining seven studies were at a serious risk of bias. The GRADE quality of evidence was very low. MARPE is an effective treatment modality for transverse maxillary deficiency (mean success rate: 93.87%). Patients showed increased mean in the skeletal and dental transverse expansion. The basal bone composition, mean alveolar bone and mean dental expansion accounted for 48.85, 7.52, and 43.63% of the total expansion, respectively. There was a certain degree of skeletal and dental relapse over time. MARPE could also cause dental, alveolar, and periodontal side effects, and have an impact on other craniofacial bones, upper airway, and facial soft tissue.

CONCLUSIONS

MARPE is an effective treatment for transverse maxillary deficiency, with a high success rate and a certain degree of skeletal and dental relapse over time.

Miniscrews position for a tissue bone borne palatal C-expander affects the displacement pattern of nasomaxillary complex: a finite element study

This study aimed to evaluate the difference in expansion patterns based on the position of miniscrews for a tissue-bone-borne palatal C-expander using a finite element method. Ten expansion models were examined, each representing a different position of miniscrews on the palate. Models A and B had miniscrews symmetrically placed 7 mm and 15 mm below the cementoenamel junction (CEJ), respectively. Models C to J had miniscrews positioned in a triangular manner at 7 mm and 15 mm below CEJ. Stress, displacement, angular changes of the bone and teeth, and changes in the nasomaxillary complex were measured using elastoplastic behavior models through static-nonlinear simulation employing an implicit method. The anterior and posterior parts of paramidpalatal suture area were identified as ANT, TPS-M, and TPS-L, and their ratio was assessed. Model A, which featured three miniscrews located 7 mm below the CEJ, exhibited the least molar inclination and the smallest amount of skeletal expansion. Model I, with two miniscrews placed between the first and second molars, demonstrated the greatest lateral displacement at point N on the nasal cavity wall, along with the smallest ratio of ANT to TPS-M or TPS-L. This finding suggests that the posterior expansion of the palate in relation to the anterior expansion was maximized. The results of this study indicate that strategic positioning of miniscrews is effective in achieving various expansion patterns based on the targeted correction areas within the nasomaxillary complex.

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.

Effects of rapid maxillary expansion on anchorage alveolar bone meta-analysis

PURPOSE

Rapid maxillary expansion (RME) is a routine method for correcting transverse maxillary deficiency. This paper investigated the effect of RME on anchorage alveolar bone and examined the differences between micro-implant-assisted RME and conventional RME.

METHODS

Relevant articles were selected from the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases. Review Manager software (v.5.3) was used for the pooled analysis and Cochran Q and I2 statistic tests were used to assess the heterogeneity.

RESULTS

Following conventional RME, the distal buccal alveolar bone thickness and the mesiobuccal alveolar thickness of the maxillary first molars were significantly reduced. Hyrax (standard mean difference [SMD]: -0.93, 95% confidence interval [CI]: -1.20-0.66) and Haas procedures (SMD: -0.88, 95% CI: -1.40-0.36) significantly reduced the buccal vertical alveolar height of the maxillary first molars. Similar results were obtained for the maxillary first premolars following RME. The thickness of the buccal alveolar bone decreased with conventional RME compared to when using the method assisted by micro-implants.

CONCLUSIONS

Conventional RME can reduce the thickness and vertical height of maxillary alveolar bone, and there is less loss of alveolar bone when using micro-implant-assisted RME. Further research is needed to validate the findings.

Treatment effects after maxillary expansion using tooth-borne vs tissue-borne miniscrew-assisted rapid palatal expansion appliance

INTRODUCTION

The study investigated the skeletal effects and root resorption in young adults with maxillary transverse deficiency after tissue-borne or tooth-borne mini-implant anchorage maxillary expansion.

METHODS

Ninety-one young adults with maxillary transverse deficiency, aged 16-25 years, were divided into 3 groups according to the treatment method: group A (n = 29) comprising patients treated with tissue-borne miniscrew-assisted rapid palatal expansion (MARPE), the group B (n = 32) comprising patients treated with tooth-borne MARPE, and the control group (n = 30) comprising patients only treated with fixed orthodontic therapies. Pretreatment and posttreatment cone-beam computed tomography images were used to assess the change of maxillary width, nasal width, first molar torque and root volume by paired t test in the 3 groups, respectively. Analysis of variance and Tukey least significant difference analysis were used to detect the changes of all descriptions among the 3 groups P <0.05.

RESULTS

In the 2 experimental groups, we observed significant increases in the width of the maxilla, nasal, and arch width, as well as the molar torque. In addition, the height of the alveolar bone and the root volume decreased significantly. There were no significant differences in the maxilla, nasal, and arch width change between the 2 groups. Group B displayed more increases in buccal tipping, alveolar bone loss, and root volume loss than group A (P <0.05). Compared with groups A and B, the control group showed negligible tooth volume loss, with no expansion effect in both skeletal and dental descriptions.

CONCLUSIONS

Tissue-borne MARPE produced the same expansion efficiency as tooth-borne MARPE. However, tooth-borne MARPE causes more dentoalveolar side effects in buccal tipping, root resorption and alveolar bone loss.

Treatment for Severe Class II Open Bite Using a Bonded Hyrax Expander, IZC Mini-Implants, and MEAW Technique in an Adolescent Patient

This case report describes the successful 3D treatment of a patient with a narrow maxilla and a severe class II open bite using a combination of a bonded hyrax expander, infrazygomatic crest mini-implants, and the multiloop edgewise arch-wire (MEAW) technique. A 14-year-old female with a thumb-sucking habit in childhood, presented with a severe open bite, a convex profile, and an obtuse nasolabial angle. Diagnosis revealed a skeletal Class II open bite with moderate crowding in the maxillary and mild crowding in the mandibular arch. Treatment objectives included eliminating the open bite, achieving normal overbite and overjet, and improving upper incisor visibility. Treatment involved the use of a bonded rapid palatal expansion device, mini-implants for maxillary intrusion, fixed appliances, vertical elastics, and a MEAW. Treatment results showed resolution of the open bite, improvement in overbite and overjet, achievement of Class I molar and canine relationships, and improved upper incisors visibility. Fixed appliances were used for the whole 22-month therapy period, and post-treatment records demonstrated that the treatment's objectives were met.

Maxillary expansion in nongrowing patients. Conventional, surgical, or miniscrew-assisted, an update

Maxillary transverse deficiency can occur in various clinical dentoskeletal deformities and include unilateral or bilateral posterior crossbite, narrow, tapering, or high palatal arch. The development of temporary anchorage devices led to a new generation of tooth-bone-borne expansion appliance using two or four screws to apply the mechanical forces to the bone and reduce the stress to the anchored teeth. The aim of these new devices is to reduce the adverse dentoalveolar effect and achieve more skeletal expansion than conventional tooth-borne rapid palatal expansion. This article reviews the age limitation and complication and soft tissue change of nonsurgical maxillary expansion. We discuss the approach of surgical maxillary expansion with maxillary skeletal expander device. The clinical case will show the benefit of nonsurgical and surgical tooth-bone-borne rapid palatal expansion.

Three-dimensional analysis of miniscrew position changes during bone-borne expansion in young and late adolescent patients

INTRODUCTION

Maxillary expansion in patients at the end of their growth relies on the possibility to use miniscrew supported expanders to apply expansion forces directly to the midpalatal suture. Although miniscrews provide a stable anchorage unit, several studies have reported that they do not remain in exactly the same position during treatment. The aim of the present study was to analyze miniscrew position changes after the expansion using bone-borne appliances in late adolescent patients.

METHODS

Nineteen patients (13 females, 6 males), with a mean age of 17.81 (SD = 4.66), were treated with a Bone-Borne Expander Device. The appliance was designed with 4 miniscrews: 2 in the anterior palatal area, at the third rugae level; 2 in the posterior area. A CBCT and an intraoral scan were obtained before treatment (T0), and then, a second CBCT was obtained after the expansion (T1). Data on peri-suture bone thickness were collected at T0, then the CBCTs were superimposed, and changes between mini-screws position on T0 and T1 were evaluated, both by linear and angular displacements.

RESULTS

Significant longitudinal differences were found in the distance of the head and the tip of miniscrews measured at the occlusal plane, as well as angular changes. Correlations between displacement measurements and peri-suture bone thickness and height measurements were found as well.

CONCLUSIONS

While acting as bone anchor units, miniscrews do not remain in the same position during bone-borne expansion. The amount of displacement was related to peri-sutural total bone height and cortical thickness, especially in the anterior area of the naso-frontal maxillary complex.

Three-dimensional comparison of bone-borne and tooth-bone-borne maxillary expansion in young adults with maxillary skeletal deficiency

OBJECTIVE

To compare the transverse dental and skeletal changes in patients treated with bone-anchored palatal expander (bone-borne, BB) compared to patients treated with tooth and bone-anchored palatal expanders (tooth-bone-borne, TBB) using cone-beam computer tomography (CBCT) and 3D image analysis.

METHODS

The sample comprised 30 patients with transverse maxillary discrepancy treated with two different types of appliances: bone-borne (Group BB) and tooth-bone-borne (Group TBB) expanders. CBCT scans were acquired before (T1) and after completion of maxillary expansion (T2); the interval was 5.4 ± 3.4 and 6.2 ± 2.1 months between the T1 and the T2 scans of Group TBB (tooth-bone-borne) and Group BB (bone-borne), respectively. Transverse, anteroposterior and vertical linear and angular three-dimensional dentoskeletal changes were assessed after cranial base superimposition.

RESULTS

Both groups displayed marked transverse skeletal expansion with a greater ratio of skeletal to dental changes. Greater changes at the nasal cavity, zygoma and orbital levels were found in Group BB. A relatively parallel sutural opening in an anterior-posterior direction was observed in Group TBB; however, the Group BB presented a somewhat triangular (V-shaped) opening of the suture that was wider anteriorly. Small downward-forward displacements were observed in both groups. Asymmetric expansion occurred in approximately 50% of the patients in both groups.

CONCLUSION

Greater skeletal vs dental expansion ratio and expansion of the circummaxillary regions were found in Group BB, the group in which a bone-borne expander was used. Both groups presented skeletal and dental changes, with a similar amount of posterior palate expansion. Asymmetric expansion was observed in both groups.

Short-term and long-term effects of miniscrew-assisted and conventional rapid palatal expansion on the cranial and circummaxillary sutures

INTRODUCTION

The objective of this study was to analyze the short-term and long-term effects of miniscrew-assisted rapid palatal expansion (MARPE) and conventional rapid palatal expansion (RPE) appliances on cranial and circummaxillary sutures as compared with a matched control group.

METHODS

One hundred and eighty cone-beam computed tomography scans for 60 subjects were evaluated for the 3 groups: (1) MARPE (n = 20; aged 13.7 ± 1.74 years), (2) RPE (n = 21; age 13.9 ± 1.14 years), and (3) control (n = 19; age 13.3 ± 1.49 years) at pretreatment (T1), postexpansion (T2), and posttreatment (T3) (T1 to T3: MARPE, 2 years 8 months; RPE, 2 years 9 months; control, 2 years 7 months). Frontonasal suture, frontomaxillary suture, zygomaticomaxillary suture, zygomaticofrontal suture, intermaxillary suture, pterygomaxillary suture, nasomaxillary suture, and zygomaticotemporal suture were measured on the right and left sides for all 3 time labels. In addition, midpalatal suture was measured at the incisor, canine, and molar levels.

RESULTS

Within-group analysis showed that MARPE and RPE led to a significant increase in the widths of frontonasal, frontomaxillary, intermaxillary, nasomaxillary, and midpalatal suture at incisor, canine, and molar levels at T2 compared with T1. Between-group analysis showed that MARPE and RPE significantly increased the width of the intermaxillary and midpalatal suture at the incisor, canine, and molar compared with controls at T2. In the long term, between-group comparisons showed no significant difference among the 3 groups except that MARPE led to a significant increase in the width of midpalatal suture at incisor, canine, and molar levels compared with RPE and controls at T3.

CONCLUSIONS

MARPE led to a significant increase in the width of the midpalatal suture at incisor, canine, and molar levels compared with RPE and controls in the long term. There was no difference in the width of other cranial and circummaxillary sutures among the 3 groups in the long term.

Three-Dimensional Finite Element Analysis of Maxillary Protraction Using Diverse Modes of Rapid Palatal Expansion

INTRODUCTION

Three-dimensional finite elemental analysis (FEA) is a contemporary research instrument for the numeric simulation of a real physical system's mechanical process. FEA can be used as a very effective tool to analyze and compare various aspects of rapid palatal expanders and to determine the stress distribution in maxillofacial bones and displacement and the biomechanical effects it has on the circummaxillary sutures. This study evaluates the effects of different modes of rapid palatal expansion on maxillary protraction as a treatment modality in skeletal Class III malocclusion by determining the stress and displacement along the circummaxillary sutures using the FEA.

MATERIALS AND METHODS

Initially, a three-dimensional finite element simulation of the maxillofacial skeleton and sutures was obtained by Mimics software (Leuven, Belgium) from the cone-beam computed tomography (Dentsply Sirona, USA) images of a 30-year-old adult with normal occlusion. A geometrical preparation of the three expansion appliances, (A) hybrid MARPE (miniscrew-assisted rapid palatal expander) appliance (Fav anchor, India), (B) tooth-borne HYRAX (hygenic rapid expander) appliance (Welcare orthodontics, Kerela), and (C) bone-borne modified MARPE appliance (Biomaterials, Korea), was transferred to ANSYS WORKBENCH, 2020 R1 software (ANSYS, Inc., USA), and three finite element models with each appliance were prepared. A protraction force of 500g was applied to the occlusal plane that is directed 20 degrees inferiorly. The tensile stress, compressive stress, and the amount of displacement on the circummaxillary sutures were assessed and compared in all the three appliances. Young's modulus (kg/mm²) and Poisson's ratio (V) were used to calculate the stress and displacement in sutures adjacent to the maxilla in different aspects.

RESULTS

On analyzing the stress distribution, the tensile stress was found to be maximum in the medial aspect of the frontomaxillary suture of the bone-borne modified MARPE appliance (C), and the minimum tensile stress was found in the lateral aspect of the sphenozygomatic suture in hybrid MARPE (A). Again, the compressive stress distribution was found to be maximum in the medial aspect of the frontomaxillary suture in all three simulations and the minimum compressive stress in the superior aspect of the internasal suture in hybrid MARPE (A) along with the frontonasal suture at its medial aspect for tooth-borne HYRAX (B) and bone-borne modified MARPE (C). Displacement of the maxilla in all the planes was observed to be the largest for the bone-borne modified MARPE (C) appliance. On the contrary, the minimum displacement was found in the tooth-borne HYRAX (B) appliance.  Conclusion: The findings reveal that all three modes of rapid palatal expanders produced stress and displacement along the circummaxillary sutures on the application of protraction force with bone-borne modified MARPE being more effective in treating posterior crossbites thereby correcting the skeletal Class III malocclusions successfully.

Effect of Injectable platelet-rich fibrin (i-PRF) on new bone formation in surgical expansion with mini-screw assisted rapid palatal expander: A dog model study

OBJECTIVES

The objective of the study is to test whether the local injection of i-PRF may affect osteoblast, blood vessels and new bone formation in surgically expanded mid palatal suture using maxillary skeletal expander.

MATERIALS AND METHODS

Eighteen adult male local breed dogs were divided randomly into three groups: group I (control), includes the expansion with maxillary skeletal expander that was done without corticotomy and i-PRF. Group II, involves the expansion that was done with mid palatal corticotomy but without i-PRF injection. Group III, has the expansion that was done with mid palatal corticotomy and has injection with 2 ml of i-PRF. Each group consisted of 6 dogs which were subdivided into 3 dogs. Three dogs were sacrificed after 15 days and the other 3 dogs were sacrificed after 45 days. The number of osteoblast, blood vessels and new bone formation percentage were statistically analyzed using Sigma plot platform. Mean and standard error, ANOVA and Duncan were performed among the different groups. Values of P ≤ 0.05 were considered significant.

RESULTS

After expansion, the i-PRF group demonstrated a considerable increase in the amount of new bone in the mid-palatal suture at 15 and 45 days compared with other 2 groups which were indicated by highest percentages of new bone formation (29.30% of 15 days and 76.55% at 45 days) if compared to control group which were (7.72% at 15 days and 22.30% at 45 days). The corticotomy groups were in between, 15.33% and 46.84% respectively. Moreover the number of osteoblasts was higher in corticotomy with i-PRF group on 15 days and decreased on 45 days than the other two groups, while the blood vessels were highest in this group than the other two groups both on 15 and 45 days.

CONCLUSION

I-PRF enhanced the production of osteoblast, blood vessels, and new bone in the surgically expanded mid palatal suture.

Comparison of 3 different bone-borne type expansion appliances used in surgically-assisted rapid palatal expansion: A finite element analysis

INTRODUCTION

This study aimed to compare the effects of 3 different bone-borne type expansion appliances used in the surgically-assisted rapid palatal expansion (SARPE) by finite element analysis.

METHODS

Three different miniscrew-supported palatal expansion appliances were modeled. Median and lateral osteotomies were performed without pterygomaxillary suture separation. Model I consisted of a palatal expander with 2 miniscrews placed 4 mm far from the midpalatal suture. In model II, 2 miniscrews were located at the alveolar ridge between the first molar and the second premolar. In model III, 4 miniscrews were placed as a combination of the first and second models. Stress distributions and amount of displacements were evaluated with Ansys software (version 19.2; Ansys, Canonsburg, Pa) for 5-mm expansion in a symmetrical finite element analysis model to reflect the clinical situation.

RESULTS

SARPE simulation using miniscrew-assisted maxillary expanders for all models showed a rotation and tipping of the maxilla. The largest displacement was found for the anterior part of the palate in model II and the posterior part in model III. Although a wedge-shaped expansion pattern was observed in all models, this form was more prominent in model II. The highest stress value (0.91 MPa) was measured in model I, and the lowest value (0.004 MPa) was measured in model II for the anterior nasal spine region. The highest stress value (0.51 MPa) was measured in model III, and the lowest value (0.12 MPa) was measured in model II for the posterior nasal spine region. The lowest stress values were measured in model II for all the craniofacial and maxillofacial structures.

CONCLUSIONS

Among the models, the lowest stress distribution conditions for craniofacial and maxillofacial structures were found in model II. The largest displacement was found at the incisors and anterior part of the maxilla for model II. The greatest displacement was found at the posterior region for model III.

Clinical advances in maxillary skeletal expansion and introduction of a new MARPE concept

BACKGROUND

Transverse maxillary deficiency, typically characterized by the clinical manifestations of unilateral or bilateral crossbite, is a common orthodontic discrepancy. The primary goal of maxillary expansion should be to obtain a nearly maximum width increase in the basal bone of the constricted maxilla and to avoid the dental expansion of the anchor teeth. The introduction of miniscrew anchorage-supported rapid maxillary expansion (MARPE) devices has helped increase the feasibility of obtaining nonsurgical transverse correction in late adolescents and young adults with optimum orthopedic effects. However, the success rate of MARPE shows a negative correlation with age. Although MARPE offers an effective method for correcting a transverse skeletal deficiency, given the appliance cost and increased risk for complications, it could present challenges for adult patients and practitioners in daily practice.

AIMS

In this article, current advances in maxillary skeletal expansion are summarized, and a new MARPE concept is introduced.

CONCLUSION

The new MARPE design offers several advantages to other existing methods: (1) it can be installed directly to the patient in the clinical setting with no additional laboratory waiting times. (2) It is purely a bone-borne appliance. (3) The appliance is designed to be placed in the thickest part of the anterior palate to maximize the cortical and trabecular bone support. (4) Allows for bicortical placement of the miniscrews with no perforations in the nasal floor. Finally, (5) offers an esthetic and minimalistic approach to maxillary skeletal expansion in late adolescent and adult patients.

Factors related to microimplant-assisted rapid palatal expansion in teenagers and young adults: A cone-beam computed tomography study

INTRODUCTION

For patients with maxillary transverse deficiency, selecting an appropriate therapeutic method is important for the treatment effect and prognosis. Our study aimed to explore factors related to microimplant-assisted rapid palatal expansion (MARPE) in teenagers and young adults using cone-beam computed tomography.

METHODS

Twenty-five patients who underwent MARPE were included in this retrospective study from February 2014 to June 2019. Midpalatal suture density (MPSD) ratio, midpalatal suture maturation (MPSM), bone effect, dentoalveolar effect, and dental effect in maxillary first molar were evaluated using cone-beam computed tomography. Spearman correlation analysis was used to analyze the correlation between the MPSD ratio, MPSM, age, and the expansion amount generated by MARPE.

RESULTS

Twenty-five patients (mean age, 19.84 ± 3.96 years; range, 15-29 years) with maxillary transverse deficiency were analyzed. Age was negatively correlated with bone expansion, alveolar expansion, and alveolar change (all P <0.05). There was a negative correlation between MPSM and nasal cavity variation, bone expansion, and alveolar change (all P <0.05). The bone expansion was negatively correlated with MPSD ratio 3 (r = -0.417; P <0.05) and MPSD ratio 4 (all P <0.05).

CONCLUSIONS

Age, MPSM, and MPSD ratio were significantly related to the MARPE effect. Age, MPSM, and MPSD ratio should be considered when choosing MARPE.

The comparison of biomechanical effects of the conventional and bone-borne palatal expanders on late adolescence with unilateral cleft palate: a 3-dimensional finite element analysis

BACKGROUND

Patients with unilateral cleft lip and palate were associated with different nasomaxillary complex from the normal population. Although the biomechanical effects of conventional rapid palatal expansion (Hyrax expansion) and bone-borne rapid palatal expansion (micro-implant-assisted expansion) in non-cleft patients have been identified by multiple studies, little is known in patients with unilateral cleft lip and palate. The purpose of this study was to investigate and compare the biomechanical effects of the conventional and bone-borne palatal expanders in a late adolescence with unilateral cleft lip and palate.

METHODS

A cone beam CT scan of a late adolescence with unilateral cleft lip and palate was selected to construct the three-dimensional finite element models of teeth and craniofacial structures. The models of conventional and born-borne palatal expanders were established to simulate the clinical maxillary expansion. The geometric nonlinear theory was applied to evaluate the Von Mises stress distribution and displacements in craniofacial structures and teeth.

RESULTS

Bone-borne palatal expander achieved more transverse movement than conventional palatal expander in the whole mount of craniofacial regions, and the maximum amount of expansion was occurred anteriorly along the alveolar ridge on cleft-side. The expanding force from born-borne palatal expander resulted in more advancement in nasomaxillary complex than it in conventional palatal expander, especially in the anterior area of the minor segment of maxilla. Stresses from the both expanders distributed in similar patterns, but larger magnitudes and ranges were generated using the bone-borne expander around the maxillary buttresses and pterygoid plates of sphenoid bone. The maximum expanding stresses from born-borne palatal expander were concentrated on palatal slope supporting minscrews, whereas those from conventional palatal expander were concentrated on the anchoring molars. In addition, the buccal tipping effect of teeth generated using the bone-borne expander was less than it using the conventional palatal expander.

CONCLUSION

Bone-borne expander generated enhanced skeletal expansion at the levels of alveolar and palate in transversal direction, where the miniscrews contributed increased expanding forces to maxillary buttresses and decreased forces to buccal alveolar. Bone-borne expanders presented a superiority in correcting the asymmetric maxilla without surgical assistant in late adolescence with unilateral cleft lip and palate.

Morphometric and volumetric analysis of the proximity between the incisive canal and maxillary central incisors during anterior retraction: a retrospective cone-beam computed tomography study

OBJECTIVES

To elucidate the relationships and factors affecting the proximity between the incisive canal (IC) and maxillary central incisors and to predict the probable outcomes after anterior tooth retraction using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Retrospective CBCT data taken before and after maxillary anterior retraction in 36 patients were used in this study. The incisive canal length (ICL), maxillary central incisor length (TL), angles between the palatal plane and axes of the maxillary alveolar border (θ1), IC (θ2), and maxillary central incisor (θ3), retraction distance (TDE), distance from the maxillary central incisors to the IC (D), cross-sectional area of the IC (CSA), and volume of the IC were evaluated. Comparison of the parameters between contact and noncontact groups were examined. Logistic regression was performed to analyze the probable outcome prediction.

RESULTS

All parameters significantly decreased after anterior retraction, except for the ICL. Eighteen roots in 12 patients contacted the IC. The θ1, θ2, θ3, and D values at all levels were significantly lower, whereas the TDE, midlevel and oral opening CSA, and volume were significantly higher in the contact group compared with the noncontact group. The larger the pretreatment θ1 and θ3 were, the higher was the chance of incisors not contacting the IC.

CONCLUSIONS

Maxillary central incisors not contacting the IC after anterior retraction was positively associated with larger degrees of pretreatment maxillary alveolar bone angle and maxillary central incisor angle.

An Innovative Design for a Versatile Maxillary Expander: FAVEX

Rapid palatal expansion has been associated with significant short and long term unwanted effects such as dentoalveolar tipping and detrimental periodontal effects when carried out in skeletally mature individuals. Mini implant assisted rapid palatal expansion (MARPE) has proven to reduce the undesirable effects seen in tooth supported expanders and allows expansion even in adults. A variety of designs have been suggested with their pros and cons. Biomechanically, it is important that the TADs attachment of the expansion appliance should be as close to the palatal vault as possible. This prevents bending of TADs and allows for a better split by keeping forces closer to the bone. According to the T zone concept given by Benedict Wilmes, the bone in the canine-premolar region is much superior for TAD insertion and stability as compared to the bone in the molar region. Considering all the above features a new MARPE appliance was designed which is versatile, anatomically compatible and easy to use. FAVEX is a treatment-centric appliance so that the treatment need not be appliance centric.

Does MARPE therapy have effects on intracranial pressure? a clinical study

Background

We aimed to evaluate possible intracranial pressure (ICP) changes caused by screw activations during active microimplant-assisted rapid palatal expansion (MARPE) therapy of post-pubertal individuals by measuring the optic nerve sheath diameter (ONSD) under ultrasonography (US) guidance.

Methods

This study’s participants comprised 15 patients (7 males, 8 females) with posterior crossbite and a mean age of 16.7 years (14.25–20.08 years). The Maxillary Skeletal Expander (MSE) appliance was used to perform MARPE in all patients. Their vital signs (heart rate, mean arterial pressure (MAP), and peripheral oxygen saturation (SpO₂)) were recorded. The ONSD was measured by US immediately before the first screw activation (T0), and the measurements were repeated 1 min (T1) and 10 min (T2) after the first activation. In the last session of active MARPE therapy, the same measurement protocol was performed as in the first activation session (T3, T4, and T5). The patients’ perceptions of pain during the screw activation were also noted at T1 and T4 using a four-category verbal rating scale (VRS-4). The significant differences among different time intervals performed with the Friedman test (for all tested variables; SpO2, MAP, Heart Rate, VRS-4 and ONSD). Spearman correlation test was used for VRS-4 and ONSD comparisons. The statistical significance level was accepted as p < 0.05.

Results

The ONSD values ​​(T1 and T4) relatively increased within 1 min after screw activation but did not reach a statistically significant level (p > 0.05). There was also no significant difference between the initial (T0) and the final (T5) ONSD values ​​during the active MARPE therapy (p > 0.05).

Conclusion

There is no changes or alterations in intracranial pressure in late adolescents during active MARPE therapy.

Supplementary information

The online version contains supplementary material available at 10.1186/s12903-022-02482-x.

Patient-reported outcomes of slow vs rapid miniscrew-supported maxillary expansion in adolescents: secondary outcomes of a randomized clinical trial

OBJECTIVES

To compare patient-reported experience between a Penn expander activated every other day vs twice daily.

MATERIALS AND METHODS

A total of 30 patients aged 12-16 years with transverse maxillary deficiency were recruited from the outpatient clinic, Faculty of Dentistry, Alexandria University (February 2019-December 2020). They were randomly allocated to two groups using block randomization (block size of six) and an allocation ratio of 1:1, which was concealed using opaque, sealed, sequentially numbered envelopes. Both groups received Penn expanders anchored by four palatal miniscrews. The slow maxillary expansion (SME) group activated the appliance once every other day. The rapid maxillary expansion (RME) group activated the appliance twice daily. Outcome measures were pain, pressure, headache, dizziness, speech difficulty, chewing difficulty, and swallowing difficulty scores rated by the participants on an 11-point numeric rating scale (NRS) at the following four time points: before appliance insertion (t1), after first activation (t2), after 1 week of activation (t3), and after last activation (t4).

RESULTS

Data of 24 patients in the SME group (n = 12, mean age = 14.30 ± 1.37 years) and RME group (n = 12, mean age = 15.07 ± 1.59 years) were analyzed. Median scores for all outcomes were in the bottom quartiles of the NRS. No difference was found between the two groups at t1 or t2. Significantly higher scores for all variables, except dizziness and headache, were reported in the RME group at t4.

CONCLUSIONS

Activation of miniscrew-supported expanders resulted in mild to moderate discomfort and functional limitation. Slow activation resulted in a better overall patient experience compared with rapid activation.

Early Class III Treatment Using a Hybrid Rapid Palatal Expander and Facemask in a Patient with Partially Edentulous Maxilla Post MNTI Removal: A Case Report

This case report describes the orthodontic treatment of a 9-year-old girl who presented with multiple agenesis, maxillary contraction, and skeletal Class III malocclusion after the surgical removal of a melanocytic neuroectodermal tumour of infancy (MNTI) or the so-called melanocytic progonoma at 40 days of age. The lack of dental anchorage in the posterior segment of the second quadrant and the search for maximum control during suture expansion to reduce dental effects led to the use of a hybrid rapid palatal expander (RPE) with dental anchorage in the first quadrant and skeletal anchorage on the two miniscrews placed in the second quadrant, to allow a more even distribution of expansion forces. The expansion procedures performed with the hybrid anchorage device and extraoral traction demonstrate the possibility of solving the contraction in the posterior segments and anterior crossbite in a few months with maximum control of the applied forces, despite the objective difficulties related to the specificity of the case.

Influence of nasal septum deviation on fluctuating asymmetries of the nasomaxillary complex: A cross-sectional study

An important parameter in diagnostic analysis and treatment planning of different biological areas is facial symmetry, and several etiological factors have been attributed to skeletal facial asymmetry. Although causality cannot be determined, previous studies have reported a relationship between the anatomical deviation of the nasal septum and facial development. Diagnosis is critical for patients in growth stages due to the association between nasal septum deviation (NSD) and abnormal growth of the nasomaxillary complex. To understand this relationship, this study aimed to investigate the influence of nasal septum deviation on fluctuating asymmetries (FA) of the nasomaxillary complex at different stages of skeletal maturation. Another goal was to determine whether an association exists between the degrees of septal deviation severity and asymmetry of the nasomaxillary complex. This was a retrospective, cross-sectional observational study comprising 60 selected cone-beam computed tomography (CBCT) scans that were divided into four groups (n = 15) according to the degree of septal deviation and skeletal maturation: mild deviation (MD; <10°), moderate to severe deviation (MSD; ≥10°), early group (EG), and late group (LG). The angle and area of deviation were measured for the greatest NSD, and a geometric morphometric approach was used to evaluate the nasal septum (NS) shape. The morphology of the nasomaxillary complex and the presence of fluctuating asymmetries were evaluated using 23 two-dimensional landmarks on the nasomaxillary complex (nasal, lateral, and palatal regions) with Procrustes ANOVA and Mann-Whitney test. Additionally, Spearman's correlation and multivariate regression were used to correlate the NSD with asymmetries in these regions. No significant differences were observed in the Procrustes FA scores of the nasomaxillary complex between the MD-EG × MSD-EG and MD-LG × MSD-LG (p > 0.05). However, the results of the multivariate regression revealed more specific aspects of asymmetry (asymmetry component), there was a positive correlation between the NSD angle and the palatal regions (p = 0.035 and p = 0.047, middle and posterior, respectively), and the nasal septum shape and anterior palatal regions (p = 0.039). The nasal and lateral regions did not correlate with the NSD angle in the multivariate regression analysis (p > 0.05). The results of this study indicate that there were no significant differences in the fluctuating asymmetry of the nasomaxillary complex between the mild and moderate to severe nasal septum deviation groups, in both early and late skeletal maturation stages. However, a positive correlation was observed in the degree of nasal septum deviation angle and asymmetry components of the middle and posterior palatal regions, likewise between the nasal septum shape and asymmetry components of the anterior palatal region. The diagnosis of nasal septum deviation by both physicians and dentists is important, as a relationship was observed with fluctuating asymmetry component of the palatal region. This information can guide the decision of the treatment planning for these individuals, and should be considered, especially in cases of severe septum deviation, due to the great anatomical proximity of these structures.

Skeletal, Dentoalveolar and Dental Changes after "Mini-Screw Assisted Rapid Palatal Expansion" Evaluated with Cone Beam Computed Tomography

The purpose of this study was to evaluate skeletal, dentoalveolar and dental changes after Mini-screw Assisted Rapid Palatal Expansion (MARPE) using tooth bone-borne expanders in adolescent patients after analyzing different craniofacial references by Cone beam computed tomography (CBCT) and digital model analysis. This prospective, non-controlled intervention study was conducted on fifteen subjects (mean age 17 ± 4 years) with transversal maxillary deficiency. Pre (T1) and post-expansion (T2) CBCTs and casts were taken to evaluate changes at the premolars and first molar areas. To compare means between two times, paired samples t- or Wilcoxon test were used following criteria. Significant skeletal changes were found after treatment for Nasal width and Maxillary width with means of 2.1 (1.1) mm and 2.5 (1.6) mm (p < 0.00005). Midpalatal suture showed a tendency of parallel suture opening in the axial and coronal view. For dentoalveolar changes, a significant but small buccal bone thickness (BBT) reduction was observed in all teeth with a mean reduction of 0.3 mm for the right and left sides, especially for the distobuccal root of the first molar on the left side (DBBTL1M) [IC95%: (−0.6; −0.2); p = 0.001] with 0.4 (0.4) mm. However, a significant augmentation was observed for the palatal bone thickness (PBT) on the left side. The buccal alveolar crest (BACL) and dental inclination (DI) showed no significant changes after treatment in all the evaluated teeth. MARPE using tooth bone-borne appliances can achieve successful skeletal transverse maxillary expansion in adolescent patients, observing small dentoalveolar changes as buccal bone thickness (BBT) reduction, which was not clinically detectable. Most maxillary expansions derived from skeletal expansion, keeping the alveolar bone almost intact with minor buccal dental tipping.

Clinical application of maxillary tissue bone-borne expander and biocreative reverse curve system in the orthodontic retreatment of severe anterior open bite with transverse discrepancy: A case report

Anterior open bite and transverse discrepancy are often accompanied by hyperdivergent skeletal patterns. In addition, degenerative joint disorders and vertical maxillary excess contribute to an unfavorable convex facial profile with a retruded chin. Correction of this complex three-dimensional problem with orthodontic treatment alone is considered challenging owing to anatomical limitations. Moreover, a history of orthodontic treatment with premolar extraction makes retreatment difficult. This case report illustrates the application of a maxillary tissue bone-borne expander and biocreative reverse curve system in a 23-year-old female patient with a severe anterior open bite and transverse discrepancy who underwent orthodontic treatment with four premolar extractions. By setting the treatment target under precise diagnosis and using appropriate appliances, a satisfactory treatment result could be achieved without orthognathic surgery.

Effect and stability of miniscrew-assisted rapid palatal expansion: A systematic review and meta-analysis

Objective

This study aimed to systematically analyze the effect and stability of miniscrew-assisted rapid palatal expansion (MARPE) to provide a reference for the clinical treatment of patients with maxillary transverse deficiency (MTD).

Methods

We searched PubMed, Science Direct, Web of Science, Embase, Cochrane Library, CNKI, and Wanfang Database for relevant studies published before February 18, 2021 and selected them according to the eligibility criteria. The Cochrane Handbook for Systematic Reviews (version 5.1.0) criteria were used for the quality assessment of randomized controlled trials, while the scoring protocol of the methodological index for non-randomized studies was used for non-randomized controlled trials. Statistical analysis was performed using the RevMan5.3 software.

Results

All the included studies showed a relatively high success rate of expansion. The changes in both the intermolar and alveolar widths after MARPE were statistically significant. MARPE exhibited greater skeletal expansion effects than did conventional RPE. The midpalatal suture was opened in parallel after MARPE. A small amount of relapse was observed 1 year after expansion. MARPE caused tooth inclination and a decrease in alveolar height, but it was less significant than in conventional RPE.

Conclusions

MARPE may be an effective treatment modality for patients with MTD. It causes great transverse skeletal expansion in late adolescence. In comparison to conventional RPE, MARPE has lower detrimental periodontal effects and has certain clinical advantages.

Skeletal expansion using a miniscrew-assisted rapid palatal expansion in a 50-year-old patient

This case report illustrates a nonsurgical treatment plan using a miniscrew-assisted rapid palatal expander (MARPE) in a 50-year-old patient with maxillary transverse deficiency. The MARPE appliance consisted of a conventional Hyrax expander anchored to 4 orthodontic miniscrews. The exact locations of the miniscrews were determined with virtual planning software. Cone-beam computed tomography (CBCT) scans were superimposed on the maxillary digital model, and 3-dimensional-printed surgical guides were used to accurately position the mini-implants. A slow expansion protocol was used, and the appliance was held in place during the entire treatment (almost 20 months). Pretreatment, postexpansion, and posttreatment CBCT scans show the parallel expansion obtained without dental torque compensation or bite opening. The posttreatment scan showed that a long period is required to complete the midpalatal suture mineralization. MARPE has proven effective in correcting transverse discrepancies, even in adults. However, posttreatment CBCT imaging showed incomplete ossification of the midpalatal suture, demonstrating that the retention period should be extended in some adult patients.