Molar inclination and surrounding alveolar bone change relative to the design of bone-borne maxillary expanders: A CBCT study

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

OBJECTIVE(S)

This study compared buccal bone thickness, dental inclinations and maxillary transverse width dimensions changes between auxiliary beta-titanium expansion arch (AEA) and miniscrew-assisted rapid palatal expansion (MARPE).

MATERIALS AND METHODS

The sample consisted of 29 patients, aged between 18 and 40 years, with transverse maxillary deficiency and treated without extractions, divided into two groups: group AEA: comprised 13 individuals (initial mean age: 29.23 ± 9.13 years) treated using auxiliary beta-titanium expansion arch; group MARPE: comprised 16 patients (initial mean age: 24.92 ± 7.60 years) treated with miniscrew-assisted rapid palatal expansion. Buccal bone thickness, dental inclinations and transverse width dimensions (dental, nasal base and jugular) were measured in cone-bean computed tomographies at pre- and post-treatment stages. The variables were compared using the independent t-test.

RESULTS

The buccal bone thickness was similar for both groups at the post-treatment stage. The second premolars were significantly more buccal inclined in the AEA group and the right maxillary first molars in the MARPE group. The intercanine and intermolar distances were statistically significantly greater in the MARPE group. Changes in dental arch transverse dimensions were significantly greater for the MARPE group.

CONCLUSION

Both treatment protocols corrected the maxillary transverse discrepancy; however, MARPE provided greater correction.

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.

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.

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.

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 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.

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.

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.

Short-term outcomes in the upper airway with tooth-bone-borne vs bone-borne rapid maxillary expanders

BACKGROUND

This study compared the area and minimal section of the nasal cavity, nasopharynx, oropharynx, and hypopharynx in cases treated with different methods of microimplant-assisted expansion.

METHODS

Based on a pilot study to calculate the sample size, 30 patients with transverse maxillary deficiency over 14 years of age were retrospectively selected. These patients had received two different types of microimplant-assisted maxillary expansion treatment (MARPE and BAME). The patient underwent Cone-Beam computed tomography (CBCT) before and after treatment (mean time 1.5 months) with MARPE or BAME and upper airway measurements (volume and minimum cross-sectional area) were taken to assess upper airways changes and compare changes between the groups. A paired sample t-test was performed to evaluate the T0-T1 change of airway measurements obtained with MARPE and BAME, and a student t-test to compare changes in airway measurements between MARPE and BAME.

RESULTS

This investigation shows a statistically significant increase in total nasopharyngeal airway volume (0.59 ± 1.42 cm3; p < 0.01), total oropharyngeal airway volume (3.83 ± 7.53 cm3; p < 0.01) and minimum oropharyngeal cross-section (53.23 ± 126.46 mm2; p < 0.05) in all cases treated with micro-screw assisted expansion. The minimal cross-sectional area of the oropharynx ((79.12 ± 142.28 mm2; p < 0.05) and hypopharynx (59.87 ± 89.79 mm2; p < 0.05) showed significant changes for cases treated with BAME. As for the comparison between cases treated with MARPE and BAME, no differences in upper airway changes have been observed, except for the minimum cross-sectional area of the nasal cavity, which increases for MARPE (52.05 ± 132.91 mm2) and decreases for BAME (-34.10 ± 90.85 mm2).

CONCLUSIONS

A significant increase in total area and minimal section at the level of nasopharynx and oropharynx was observed in cases treated with BAME. Regarding the comparison of MARPE and BAME treatments, no differences were found in the total airway volume and minimal section in upper airway except for the minimum cross section of the nasal cavity that increases for MARPE and decreases for BAME.

Comparison of the skeletal, dentoalveolar, and periodontal changes after Ni-Ti leaf spring expander and rapid maxillary expansion: a three-dimensional CBCT based evaluation

BACKGROUND

The aim of the present study was twofold:(1) three-dimensionally evaluate the quantitative skeletal and dentoalveolar changes after Ni-Ti leaf spring expander (leaf expander) and rapid maxillary expansion (RME) in mixed dentition patients;(2) analyze the modifications of the buccal alveolar bone plate of the maxillary first permanent molars.

METHODS

Patients who underwent CBCT scans before and after maxillary expansion were randomly selected from the records archived at the Department of Biomedical Surgical and Dental Sciences, University of Milan, Italy. Inclusion criteria were the following: no systemic disease or syndromes; maxillary transverse deficiencies (difference between the upper intermolar width and the lower intermolar width of at least 3 mm and/or clinical need based on radiographic evaluation), early mixed dentition with ages between 7 to 10 years old; cervical vertebra maturation stage (CVMS) 1 or 2; no pathologic periodontal status; skeletal class I or II; maxillary expander cemented on the upper second deciduous molars. Exclusion criteria were the following: patients with pubertal or post-pubertal stage of development (CVMS 3-6); late deciduous or late mixed dentition, impossibility to use the second primary molar as anchorage; skeletal class III malocclusion; craniofacial syndromes; patients unable to be followed during the treatment period. Twenty-three patients treated with Leaf Expander, 11 males (mean age 7.8 ± 0.6 years) and 12 females (mean age 8.1 ± 0.8 years), met the inclusion criteria and constituted the case group. Twenty-four (control group) treated with conventional RME, 12 males (mean age 8.4 ± 0.9 years) and 12 females (mean age 8.1 ± 0.7 years). The paired-sample T test was used for intra-group comparison to evaluate the difference between before (T1) and after (T2) maxillary expansion. Independent sample t-test was computed to perform between groups comparison of the skeletal, dentoalveolar, and periodontal changes.

RESULTS

The Leaf Expander and RME group showed a significant increase between T1 and T2 for most of the skeletal and dentoalveolar variables. Concerning the skeletal variables only the RME demonstrated a significant increase at the level of the posterior nasal (PNW) and apical base width (PABW) and maxillary mid-alveolar width (MMW). Despite this, when compare with the Leaf Expander, the RME group exhibited a statistically larger width increase for only two skeletal parameters: PNW (p = 0.03) and MMW (p = 0.02). No significant changes at the periodontal level were found in either group.

CONCLUSIONS

According to the current research, the authors confirm the effectiveness of the Leaf Expander and RME to produce similar skeletal and dentoalveolar effects in mixed dentition subjects. Moreover, the devices anchored to deciduous teeth did not reduce the thickness and height of the buccal bone at the level of the maxillary permanent first molars in either of the two groups.

Changes in Molar Tipping and Surrounding Alveolar Bone with Different Designs of Skeletal Maxillary Expanders

This study compared the buccolingual angulation (BLA) of the upper and lower first permanent molars before and after using the different methods of microimplant-assisted expansion in adults and its influence on bone insertion loss.

METHODS

Cone-beam computed tomography scans taken before and after the expansion in 36 patients (29.9 ± 9.4 years) were used to assess dental and periodontal changes and compare changes between the groups.

RESULTS

This research shows a statistically significant increase in the BLA of the upper first molars. An increase of the BLA of the lower molars is also observed in MARPE. Regarding the comparison between cases treated with MARPE (4.42° ± 10.25°; 3.67° ± 9.56°) and BAME (-0.51° ± 4.61°; 2.34° ± 4.51°), it was observed that upper molar torque increased significantly less in cases treated with BAME. In cases with CWRU < 96° at T0, a slight bone insertion gain was observed at T1, whereas if CWRU ≥ 96°, a slight bone insertion loss was observed. Regarding the labial cortical bone loss, a slight gain of CBW was observed in all cases. This labial cortical enlargement (T0-T1) is greater in cases where the CWRU < 96° at T0.

CONCLUSIONS

Patients treated with MARPE show torque increase in the teeth selected to support the expansion appliance compared to cases treated with BAME. In cases where the BLA at T0 < 96°, an increase in thickness and cortical insertion is observed in the upper molars after treatment with disjunction appliances assisted with microscrews.

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.

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.

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.

Skeletal and dentoalveolar effects of slow vs rapid activation protocols of miniscrew-supported maxillary expanders in adolescents: A randomized clinical trial

OBJECTIVES

To compare between skeletal and dentoalveolar effects of slow and rapid activation of miniscrew-supported expanders.

MATERIALS AND METHODS

A total of 30 patients were randomly allocated to two groups using block randomization and the allocation ratio 1:1. Both groups received maxillary expanders anchored using four miniscrews. Activation protocol was once every other day in the slow expansion (SME) group and twice daily in the rapid expansion (RME) group. Cone-beam computed tomography (CBCT) scans were obtained before expansion and after removal of the expanders. Transverse skeletal and dentoalveolar changes were measured using CBCT.

RESULTS

A total of 12 patients in the SME group (mean age, 14.30 ± 1.37 years) and 12 patients in the RME group (mean age, 15.07 ± 1.59 years) were analyzed. RME showed significantly greater widening of the mid-palatal suture at the level of first molars (mean difference [SME - RME] = -0.61 mm), and a greater increase in right and left molar buccal inclination (mean difference= -3.83° and -2.03°, respectively). Percentage of skeletal expansion relative to the jackscrew opening was not significantly different between the groups. Palatal inflammation was evident following appliance removal. Miniscrew mobility and bending were observed with RME.

CONCLUSIONS

Both SME and RME were effective in correcting skeletal transverse maxillary deficiency. However, RME resulted in more buccal tipping of maxillary molars and in miniscrew failures and bending.

Three-dimensional evaluation of skeletal and dental effects of treatment with maxillary skeletal expansion

INTRODUCTION

The objective was to determine the skeletal and dental changes with microimplant assisted rapid palatal expansion (MARPE) appliances in growing (GR) and nongrowing (NG) patients using cone-beam computed tomography and 3-dimensional imaging analysis.

METHODS

The sample consisted of 25 patients with transverse maxillary discrepancy treated with a maxillary skeletal expander, a type of MARPE appliance. Cone-beam computed tomography scans were taken before and after maxillary expansion; the interval was 6.0 ± 4.3 months. The sample was divided into GR and NG groups using cervical vertebral and midpalatal suture maturation. Linear and angular 3-dimensional dentoskeletal changes were assessed after cranial base superimposition. Groups were compared with independent-samples t test (P <0.05).

RESULTS

Both groups displayed marked transverse changes with a similar ratio of skeletal to dental transverse changes and parallel sutural opening from the posterior nasal spine-anterior nasal spine; a similar amount of expansion occurred in the anterior and the posterior regions of the maxilla. The maxilla expanded skeletally without rotational displacements in both groups. The small downward-forward displacements were similar in both groups, except that the GR group had a significantly greater vertical displacement of the canines (GR, 1.7 ±1.0 mm; NG, 0.6 ± 0.8 mm; P = 0.02) and anterior nasal spine (GR, 1.1 ± 0.6 mm; NG, 0.5 ± 0.5 mm; P = 0.004).

CONCLUSIONS

Treatment of patients with MARPE appliance is effective in GR and NG patients. Although greater skeletal and dental changes were observed in GR patients, a similar ratio of skeletal to dental transverse changes was observed in both groups.

Effect of Low-Intensity Pulsed Ultrasound (LIPUS) on Alveolar Bone during Maxillary Expansion Using Clear Aligners

The present study evaluated the possible effect of low-intensity pulsed ultrasound (LIPUS) on buccal bone plate thickness and height after maxillary arch expansion using clear aligners. The cone beam computed tomography (CBCT) of before and immediately after maxillary arch expansion (3 mm per side) of 28 adult patients (18 in LIPUS group and 10 in control) (average age $36.2\pm 13.2$ years old) was analyzed. The wearing protocol of clear aligners in the LIPUS group was to change the aligners every 4 to 5 days, while the wearing protocol in the control group (without LIPUS) was to change the aligners every 7 to 10 days. Bone thickness at 3 mm and 6 mm from the buccal alveolar bone crests, along with the measurements of buccal alveolar bone heights, was measured in standardized sagittal sections. Data were analyzed through paired sample $t$ -test and the Wilcoxon test. The results were given as $\text{mean}\pm \text{standard}\text{deviation}$ and 95% confidence intervals. $p$ value < 0.05 was considered statistically significant. The results showed significant increase in bone height in both groups. However, comparison of both LIPUS and control groups showed no statistically significant difference in bone thickness or bone height. The results of this study showed that the use of LIPUS together with accelerated aligner tray change protocol did not affect alveolar bone integrity when compared to the control group.

Effectiveness of miniscrew assisted rapid palatal expansion using cone beam computed tomography: A systematic review and meta-analysis

Objective

This study aims to examine the effectiveness of miniscrew assisted rapid palatal expansion (MARPE) treatment in late adolescents and adult patients using cone-beam computed tomography (CBCT).

Methods

Literature search was conducted in five electronic databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) based on the PICOS keyword design focusing on MARPE. Out of the 18 CBCT screened outcomes, only nine parameters were sufficient for the quantitative meta-analysis. The parameters were classified into three main groups 1) skeletal changes, 2) alveolar change, and 3) dental changes. Heterogeneity test, estimation of pooled means, publication bias, sensitivity analysis and risk of bias assessment were also performed.

Results

Upon database searching, only 14 full-text articles were qualified from the 364 obtained results. Heterogeneity test indicated the use of the random-effects model. The pooled mean estimate were as follows 1) Skeletal expansion zygomatic width, 2.39 mm; nasal width, 2.68 mm; jugular width, 3.12 mm; and midpalatal suture at the posterior nasal spine and anterior nasal spine, 3.34 mm and 4.56 mm, respectively; 2) Alveolar molar width expansion, 4.80 mm; and 3) Dental expansion inter-canine width, 3.96 mm; inter-premolar width, 4.99 mm and inter-molar width, 5.99 mm. The percentage of expansion demonstrated a skeletal expansion (PNS) of 55.76%, alveolar molar width expansion of 24.37% and dental expansion of 19.87%.

Conclusions

In the coronal view, the skeletal and dental expansion created by MARPE was of the pyramidal pattern. MARPE could successfully expand the constricted maxilla in late adolescents and adult patients.

Standard orthodontic treatment after condylectomy for patients with active unilateral condylar hyperplasia

INTRODUCTION

Unilateral condylar hyperplasia (UCH) is a progressive, nonneoplastic overgrowth of the condyle of the temporomandibular joint. For treating active UCH, a popular method combines orthognathic surgery with high condylectomy and orthodontic treatment. The goal of this study was to introduce a new method to correct asymmetry for active UCH.

METHODS

Retrospectively, 47 patients with active UCH were divided into horizontal-type, vertical-type, and combined-type. All patients were treated with condylectomy plus postsurgery standard orthodontics (CPSO) with applied miniscrews implanted in infrazygomatic crest and hard palate to intrude affected side of maxillary molars and apply intermaxillary traction for contralateral molars. Cone-beam computed tomography was taken at presurgery, postsurgery, and the end of orthodontics (T3).

RESULTS

In the vertical (n = 10) and combined (n = 28) types, deviation of the chin and the canting of the mandible and maxillary occlusal plane were significantly reduced at T3. A difference in the torque of bilateral maxillary first molar (U6) and bilateral mandibular first molar (L6) was significantly reduced at T3. The anterior, superior, and posterior joint spaces in the vertical-type and combined-type were significantly decreased at T3 compared with postsurgery. In contrast, in the horizontal-type group (n = 9), the deviation of the chin was corrected; however, the canting of the mandible and maxillary occlusal plane was significantly increased at T3 compared with presurgery.

CONCLUSIONS

CPSO restored facial and occlusal symmetry for vertical-type and combined-type active UCH and returned affected-side condyle to the glenoid fossa. However, CPSO was not suitable for treating the horizontal-type UCH.

Effect of sinus proximity, alveolar bone level, and initial buccolingual inclination on behavior of maxillary first molar under expansion force: a finite element analysis

BACKGROUND

The primary aim of this study is to determine whether sinus proximity increases or decreases molar tipping under the force of expansion; a secondary aim is to compare the effect of the initial buccal inclination, alveolar bone loss, and sinus proximity to molar movement under expansion force, by assessing the stress distribution of the periodontal ligament and the changes in the moment/force (M/F) ratio).

METHODS

Twenty different 3-dimensional models were created by changing the buccal inclination (0°,5°,10°,15°, and 20°) value of maxillary molar and simulating different amounts of alveolar bone loss (0, 2,4, and 6 mm) in the basic model. Additionally, an artificial sinus was added to the basic model, and the penetration of the roots into the sinus to different levels (2, 4, and 6 mm) was simulated separately. Thus, 9 additional models were created. The M/F ratio, location of the center of resistance, and principal stresses on the periodontal ligament were analyzed for each of the 29 models separately in a finite element analysis.

RESULTS

The M/F ratio increased as initial buccal inclination or bone loss increased. As the amount of simultaneous penetration of 3 roots into the sinus increased, the M/F ratio decreased. Incremental changes of both the initial inclination value and the amount of bone loss resulted in higher maximum compressive stress on the apices of the buccal roots.

CONCLUSIONS

Increases in alveolar bone loss and buccal inclination caused increases in the periodontal stress. Penetration of the roots into the sinus provides bicortical anchorage and could prevent unwanted crown tipping.

Periodontal effects of maxillary expansion in adults using non-surgical expanders with skeletal anchorage vs. surgically assisted maxillary expansion: a systematic review

OBJECTIVES

Describe and compare harmful periodontal effects as a consequence of maxillary expansion in adult patients with different types of anchorage devices in non-surgical expanders with skeletal anchorage and surgically assisted maxillary expansion.

MATERIALS AND METHODS

An exhaustive search was carried out on the electronic databases PubMed (MEDLINE), Embase, Cochrane and LILACS. Additionally, journal references and grey literature were searched without any restrictions. After the selection and extraction process; risk of bias was assessed by the ROB-1 Cochrane tool and Newcastle-Ottawa Scale (NOS) for randomized trials and cohort studies, respectively.

RESULTS

Of 621 studies retrieved from the searches, six were finally included in this review. One of them presented a low risk bias, while five were excellent respective to selection, comparability and outcomes. Results showed that maxillary expansion in adults using non-surgical expanders (bone-borne or tooth-bone-borne with bicortical skeletal anchorage) produce less harmful periodontal effects, such as: alveolar bending with an average range from 0.92° to 2.32°, compared to surgically assisted maxillary expansion (tooth-borne) of 6.4°; dental inclination with an average range from 0.07° to 2.4°, compared to surgically assisted maxillary expansion (tooth-borne) with a range from 2.01° to 5.56°.

CONCLUSIONS

Although limited, the current evidence seems to show that the bone-borne or tooth-bone-borne with bicortical skeletal anchorage produces fewer undesirable periodontal effects.

Development of a maxillomandibular arch form based on the center of resistance of teeth using cone-beam computed tomography

INTRODUCTION

Controlling transverse discrepancies is necessary to ensure stable and functional occlusion. Altered molar inclinations can camouflage the transverse relationship. The purpose of this research was to evaluate the maxillomandibular relationship of the center of resistance (CR) of the arch form created by the CR of teeth and compare these CR arch forms by their skeletal patterns.

METHODS

Sixty patients with minor crowding and normal posterior overjet were divided into 3 groups according to ANB angle: skeletal Class I group had ANB angle between 0° and 4° (n = 20), skeletal Class II group had ANB angle >4° (n = 20), and skeletal Class III group had ANB angle <0° (n = 20). The 3-dimensional coordinates of the CR were estimated using cone-beam computed tomography images and projected on the CR occlusal plane to obtain the 2-dimensional coordinates. The CR arch forms were constructed and evaluated using Matlab (MathWorks, Natick, Mass).

RESULTS

On comparing maxillomandibular CR arch form widths, the maxilla was significantly larger than the mandible of the canine and first premolar. The mandible was larger in the first molar of the skeletal Class III group. The maxillomandibular CR arch form width ratios were between 0.97 and 1.35. On comparing maxillomandibular CR arch form areas, the maxilla was significantly larger than the mandible in the anterior segment, and the mandible was larger in the posterior segment. The ratios were between 0.86 and 2.25. In between-group comparison, the skeletal Class III group showed significantly greater arch forms in the mandible.

CONCLUSIONS

CR arch forms had significant maxillomandibular differences throughout the arch. The maxillomandibular ratios could be a reference for site-specific transverse discrepancy analysis.

Geometry of anchoring miniscrew in the lateral palate that support a tissue bone borne maxillary expander affects neighboring root damage

Anchoring miniscrews used for a tissue bone borne maxillary expander (C-expander) can fail if they contact tooth roots or perforate the maxillary sinus. Cone beam computed tomography images were reviewed retrospectively to evaluate the geometric factors of miniscrew placement in the palate that contribute to root proximity (RP) and sinus perforation (SP), and to investigate the differences of miniscrew placement depth (PD) and placement angle (PA) among the groups in each variable from 340 anchoring miniscrews on 70 patients whose C-expanders showed sufficient stability after palatal expansion for orthodontic treatment. Two types of miniscrews were used: a self-tapping miniscrew with 1.8 mm-in-diameter, and a self-drilling miniscrew with 1.6 mm-in-diameter. While the self-tapping larger diameter miniscrew influenced root proximity significantly, the screw location and PD affected the rate of sinus perforation. PA was significantly different between the right and left sides of the palate. The results of this study confirmed that root proximity and sinus perforation of anchoring miniscrews in a tissue bone borne palatal expander occurred due to certain risk factors, even when the palates were expanded successfully. Knowledge of these factors can help the clinician place miniscrews with less risk of root proximity or sinus perforation.

Identifying cortical plate inclination as a parameter to re-assess transverse discrepancies in untreated adults with different vertical facial heights-A retrospective CBCT study

OBJECTIVE

To determine the inclination angles of buccal, palatal cortical plates and assess its harmony with existing molar buccolingual inclination in adults with different vertical facial heights. The aim of this study was to identify the role of cortical plate inclination as a diagnostic tool for determining alveolar support in adults with transverse discrepancies.

MATERIALS AND METHODS

One-hundred and fifty seven CBCTs (50-Hypo-divergent, 51-Normo-divergent and 56-Hyper-divergent growth patterns) of untreated adults were utilized. Cross-sectional slices with respect to the maxillary first molar were taken as orientation landmarks in defined reference planes. Inclination angles for the first molar, buccal and palatal cortical plate were determined with respect to the palatal plane. ANOVA and Post Hoc Tukey's HSD test were carried out to determine significant differences between groups.

RESULTS

Molar inclination was significantly greater in hyper-divergent groups compared to normo-divergent and hypo-divergent groups (P < .05). Greater variation between molar inclination and cortical plate inclination (buccal and palatal) was seen in hyper-divergent groups (P < .05). Hypo-divergent and normo-divergent groups showed almost similar molar and cortical plate inclinations; however, there was a significant difference between the buccal and palatal cortical plates (P < .05).

CONCLUSIONS

Cortical plate inclination is in agreement with molar inclination in hypo- and normo-divergent groups when compared to hyper-divergent groups. In adults with decreased/normal facial heights, greater balance and harmony is observed between the dental and alveolar substructures in the posterior region. In adults with increased facial heights, a greater amount of dentoalveolar compensation is seen with respect to the molar and its surrounding bone support.

Stress distribution and displacement of three different types of micro-implant assisted rapid maxillary expansion (MARME): a three-dimensional finite element study

Abstract

Background/objective

Until 2010, adults underwent surgical treatment for maxillary expansion; however, with the advent of micro-implant-assisted rapid maxillary expansion (MARME), the availability of less invasive treatment options has increased. Nevertheless, individuals with severe transverse maxillary deficiency do not benefit from this therapy. This has aroused interest in creating a new device that allows the benefit of maxillary expansion for these individuals. The aim of this study was to evaluate the efficacy of three MARME models according to tension points, force distribution, and areas of concentration in the craniofacial complex when transverse forces are applied using finite element analysis.

Materials and methods

Digital modeling of the three MARME models was performed. Model A comprised five components: one body screw expander and four adjustable arms with rings for mini-implant insertion. These arms have an individualized height adjustment that allows MARME positioning according to the patient’s palatal anatomy, thereby preventing body screw expander collision with the lateral mucosa in severe cases of maxillary deficiency. Model B was a maxillary expander with screw rings joined to the body, and model C was similar to model B, except that model C had open rings for the insertion of the mini-implants. Through the MEF (Ansys software), the stresses, distribution, and area of concentration of the stresses were evaluated when transverse forces of 7.85 N were applied.

Results

The three models maintained the following pattern: model C presented weak stress peaks with limited distribution and lower concentration area, model B obtained median stress peaks with better distribution when compared to that of model C, and model A showed better stress distribution and larger concentration area. In model A, tensions were located in the lateral lamina of the pterygoid process, which is an important site for maxillary expansion. The limitation of the present study was that it did not include the periodontal tissues and muscles in the finite element method evaluation.

Conclusions

Model A showed the best stress distribution conditions. In cases of severe atresia, model A seems to be an excellent option.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40510-021-00357-5.

Effect of Different Head Hole Position on the Rotational Resistance and Stability of Orthodontic Miniscrews: A Three-Dimensional Finite Element Study

The orthodontic miniscrew is driven into bone in a clockwise direction. Counter-clockwise rotational force applied to the implanted miniscrew can degrade the stability. The purpose of this three-dimensional finite element study was to figure out the effect of shifting the miniscrew head hole position from the long axis. Two miniscrew models were developed, one with the head hole at the long axis and the other with an eccentric hole position. One degree of counter-clockwise rotation was applied to both groups, and the maximum Von-Mises stress and moment was measured under various wire insertion angles from −60° to +60°. All Von-Mises stress and moments increased with an increase in rotational angle or wire insertion angle. The increasing slope of moment in the eccentric hole group was significantly higher than that in the centric hole group. Although the maximum Von-Mises stress was higher in the eccentric hole group, the distribution of stress was not very different from the centric hole group. As the positive wire insertion angles generated a higher moment under a counter-clockwise rotational force, it is recommended to place the head hole considering the implanting direction of the miniscrew. Clinically, multidirectional and higher forces can be applied to the miniscrew with an eccentric head hole position.

Treatment of maxillary transversal deficiency by using a mini-implant-borne rapid maxillary expander and aligners in combination

Bone-borne rapid maxillary expansion distraction devices are used to achieve a more skeletal expansion and to avoid dental side effects of conventional expanders such as tipping of anchorage teeth. In this article, we report the use of a prefabricated expander fixed on 2 mini-implants in the anterior palate. This allows for the insertion of the mini-implants and the expander to occur without the need for an impression or any laboratory procedures. Especially when aligners are going to be used, the use of a mini-implant-borne expander seems to be reasonable because the expander can be left in place as a skeletal retainer during the aligner finishing.

Computational Fluid Dynamics Analysis of Nasal Airway Changes after Treatment with C-Expander

The use of the C-expander is an effective treatment modality for maxillary skeletal deficiencies which can cause ailments and significantly reduce life expectancy in late adolescents and young adults. However, the morphological and dynamic effects on the nasal airway have not been reported. The main goal of this study was to evaluate the nasal airway changes after the implementation of a C-expander. A sample of nine patients (8 females, 1 male, age range from 15 to 29 years) was included. The morphology parameters and nasal airway ventilation parameters of pretreatment and posttreatment were measured. All study data were normally distributed. A paired t-test was used to evaluate the changes before and after treatment. After expansion, the mean and standard deviation values of intercanine maxillary width (CMW) and intermolar maxillary width (MMW) increased from 35.75 ± 2.48 mm and 54.20 ± 3.17 mm to 37.87 ± 2.26 mm (P < 0.05) and 56.65 ± 3.10 mm (P < 0.05), respectively. The nasal cavity volume increased from 20320.00 ± 3468.25 mm³ to 23134.70 ± 3918.84 mm³ (P < 0.05). The nasal pressure drop decreased from 36.34 ± 3.99 Pa to 30.70 ± 3.17 Pa (P < 0.05), while the value of the maximum velocity decreased from 6.50 ± 0.31 m/s to 5.85 ± 0.37 m/s (P < 0.05). Nasal resistance dropped remarkably from 0.16 ± 0.14 Pa/ml/s to 0.08 ± 0.06 Pa/ml/s (P < 0.05). The use of C-expander can effectively broaden the area and volume of the nasal airway, having a positive effect in the reduction of nasal resistance and improvement of nasal airway ventilation. For patients suffering from maxillary width deficiency and respiratory disorders, a C-expander may be an alternative method to treat the disease.

Finite element analysis of C-expanders with different vertical vectors of anchor screws

INTRODUCTION

C-expanders are tissue- and bone-borne maxillary expanders that are anchored by 6 orthodontic miniscrews, 3 on each side of the palate. The purpose of the study was to investigate the effect of C-expanders on the circummaxillary sutures and bucco-palatal axis of teeth in 3-dimensional finite element analyses when anchor screw vectors are different.

METHODS

Five expansion models were studied on the basis of the vertical positions of anchor screws on the palate. Anchor screws for models A, B, and C were placed symmetrically at 4 mm, 7 mm, and 15 mm below the cementoenamel junction (CEJ), respectively. Anchor screws for models D and E were placed asymmetrically at 4 mm and 15 mm below CEJ and 7 mm and 15 mm below CEJ, respectively. Stress, displacement, and angular changes of the bone and teeth were measured in elastoplastic behavior models using a static-nonlinear simulation in an implicit method.

RESULTS

Symmetrical and asymmetrical anchor screw placement with different vertical vectors were compared using finite element analyses on 5 models.

CONCLUSIONS

Using different vectors of anchor screws for C-expanders does change the pattern of palatal expansion (null hypothesis was rejected). The current investigation presents a promising future of controlled asymmetric skeletal maxillary expansion when asymmetric maxillary architecture needs to be corrected for successful orthodontic outcomes without involving orthognathic surgeries.

Effectiveness of Dental and Maxillary Transverse Changes in Tooth-Borne, Bone-Borne, and Hybrid Palatal Expansion through Cone-Beam Tomography: A Systematic Review of the Literature

Background and Objectives: Palatal expansion is a common orthodontic technique able to increase the transverse changes for subjects with constricted maxillary arches. The aim of the present investigation was to evaluate through a systematic review the tomography effectiveness of different palatal expander approaches. Materials and Methods: The database used to perform the screening and determine the eligibility of the clinical papers was PubMed (Medline). Results: The database search included a total of 284 results, while 271 articles were excluded. A total of 14 articles were included for the qualitative assessment. Conclusions: The effectiveness of the present studies reported that skeletal expansion was a useful approach to increase the transverse changes for subjects with constricted maxillary arches.

Tooth-Bone-Borne Vs. Bone-Borne Palatal Expanders: A Systematic Review

The aim of this review was to evaluate the current evidence regarding post-treatment effects of tooth-bone-borne vs. bone-borne expanders. A search was conducted in MEDLINE via PubMed, Web of Science, Scopus, Cochrane Library, Google Scholar, and Open Gray; in addition to a hand search in reference lists of selected articles and creating a search alert in electronic databases. Selection criteria included randomized and prospective clinical trials comparing post-expansion skeletal and/or dento-alveolar effects of tooth-bone-borne expanders to those of bone-borne expanders. Following study retrieval and selection, relevant data was extracted, and risk of bias was assessed using the revised RoB 2 tool for randomized clinical trials. After examining 10 full text articles, one randomized clinical trial was finally included. The study compared the dento-alveolar effects of tooth-bone-borne and bone-borne expanders, following expansion and after 6 months, using digital dental casts. Using the RoB 2 tool, the study was judged overall to show some concerns. A definitive conclusion could not be drawn from this systematic review due to the scarcity of clinical trials tackling the research question. A need for future well-conducted research was highlighted in this review.

Skeletal and dental changes after maxillary expansion with a bone-borne appliance in young and late adolescent patients

INTRODUCTION

Rapid palatal expansion is a common therapy during orthodontic treatment and could be a preliminary step for correcting different malocclusions; furthermore, this treatment could be necessary at any age. Different anchorage approaches have been proposed to obtain an effective skeletal result, although every device produces both dental and skeletal effects. This study aimed to compare the dentoskeletal effects of a bone-borne palatal expander considering 2 groups of patients of different ages.

METHODS

Twenty-four patients consecutively treated were included in the study; patients were divided into 2 groups according to their age: group 1 with age ≤16 years and group 2 patients >16 years. All patients had a preexpansion cone-beam computed tomography scan; a second scan was required at the end of activations. All patients received a bone-borne appliance anchored on 4 miniscrews.

RESULTS

Significant intragroup differences were found for maxillary width and dental diameters. No significant differences were found between groups with regard to longitudinal changes, except for the maxillary right plane.

CONCLUSIONS

The use of bone-borne maxillary expansion was effective in generating palatal widening both in growing and young adult patients. No significant skeletal or dental differences were found between groups.

Evaluation of interradicular space, soft tissue, and hard tissue of the posterior palatal alveolar process for orthodontic mini-implant, using cone-beam computed tomography

INTRODUCTION

To investigate the anatomy of the posterior palatal alveolar process, which is often used for placement of the orthodontic mini-implant (OMI), and to suggest simple guidelines for safe placement of OMI.

METHODS

Cone-beam computed tomography (CBCT) scans of 60 patients (30 men, 30 women; age range, 18-39 years; average age, 25.8 years) was used to measure the palatal interradicular distance, the palatal bone thickness, and the palatal soft-tissue thickness. Measurements were performed on the area from the maxillary canine to the maxillary second molar based on the vertical distance apical from the cementoenamel junction. The CBCT data were analyzed by Bonferroni correction for multiple testing and the multivariable mixed linear model.

RESULTS

The palatal interradicular distance was the widest between the second premolar and the first molar and the narrowest between the first and second premolars. The palatal bone thickness at interdental sites was the thickest between the first and second premolars and the thinnest between the first and second molars. The interdental palatal soft-tissue thickness from the canine to the second premolar was thicker than any other area. There were minor measurement differences between genders and positive correlations between vertical distance from the cementoenamel junction plane and all of the parameters.

CONCLUSION

In this study, we evaluated the anatomy of the posterior palatal area using CBCT scans of adult patients. The data will provide guidelines to the clinicians before OMI placement in the posterior palatal alveolar process.

Comparison of skeletal maxillary transverse deficiency treated by microimplant-assisted rapid palatal expansion and tooth-borne expansion during the post-pubertal growth spurt stage

OBJECTIVE

To investigate the efficacy of microimplant-assisted rapid palatal expansion (MARPE) to treat skeletal maxillary discrepancies during the post-pubertal growth spurt stage.

MATERIALS AND METHODS

Sixty patients with skeletal maxillary transverse deficiency during the post-pubertal growth spurt stage were randomly divided into MARPE and Hyrax groups. Thirty patients (mean age: 15.1 ± 1.6 years) were treated using the four-point MARPE appliance; 30 patients (mean age, 14.8 ± 1.5 years) were treated using the Hyrax expander. Cone beam computed tomography scans and dental casts were obtained before and after expansion. The data were analyzed using paired t-tests and independent t-tests.

RESULTS

The success rates of midpalatal suture separation were 100% and 86.7% for MARPE and Hyrax groups, respectively. Palatal expansion and skeletal to dental ratio at the first molar level were greater in the MARPE group (3.82 mm and 61.4%, respectively) than in the Hyrax group (2.20 mm and 32.3%, respectively) (P < .01). Reductions in buccal alveolar bone height and buccal tipping of the first molars were less in the MARPE group than in the Hyrax group (P < .01).

CONCLUSIONS

MARPE enabled more predictable and greater skeletal expansion, as well as less buccal tipping and alveolar height loss on anchorage teeth. Thus, MARPE is a better alternative for patients with skeletal maxillary deficiency during the post-pubertal growth spurt stage.

Radiological evaluation of the bone and soft tissue thicknesses of the palate for using a miniscrew-supported maxillary skeletal expander

PURPOSE

The purpose of this study was to determine the palatal bone and soft tissue thicknesses using a miniscrew-supported maxillary skeletal expander (MSE) in Class III malocclusion.

METHODS

The thicknesses of the palatal bone and soft tissue were measured in cone-beam computed tomography images obtained from 58 patients. All 20 points were crossing points between five levels, which were defined at 3 mm intervals relative to the line connecting the central fossae of the first molar (Level 0), and 2 mm and 4 mm lateral to the anteroposterior reference line (AP line).

RESULTS

The palatal bone was significantly thicker in males than females in the anterior palate up to Level 0, while there was no significant sex-related difference in the posterior palate. There was a tendency for the thickness to decrease in the posterior direction, except in females at 2 mm lateral to the AP line. The palatal soft tissue was significantly thicker in males than females in all positions. At 2 mm lateral to the AP line, the palatal soft tissue thickness decreased in the posterior direction. A 4 mm lateral to the AP line, it initially decreased in the posterior direction, and then increasing again at Level - 6 (6 mm posterior of Level 0). As the lateral distance from the AP line increased, the palatal bone thickness decreased while the palatal soft tissue thickness increased.

CONCLUSIONS

These findings provide quantitative data on the palatal bone and soft tissue thicknesses for the miniscrew-supported MSE in the posterior palate.

Palatal temporary skeletal anchorage devices (TSADs): What to know and how to do?

OBJECTIVES

Since palatal temporary skeletal anchorage devices (TSADs) have become important tools for orthodontic treatment, this narrative review was aimed to provide an updated and integrated guidelines for the clinical application of palatal TSADs.

SETTING AND SAMPLE POPULATION

A narrative review article including researches on palatal TSADs in orthodontics related to anatomy, success rate and clinical application.

MATERIALS AND METHODS

The anatomical characteristics, success rate and its consideration factors and clinical application of palatal TSADs based on the direction of tooth movement were evaluated.

RESULTS

To improve the stability of TSADs, hard tissue factors such as bone depth, cortical bone thickness, bone density and soft tissue thickness were evaluated. Anatomically risky structures, including the nasopalatine foramen, canal and the greater palatine foramen, nerve, vessel need to be identified before placement. The success rate of palatal TSADs was greater than that of the buccal inter-radicular space. Palatal TSADs have been used for various purposes because they can control tooth movement in all directions and, three-dimensionally; their applications include the retraction of anterior teeth, protraction of posterior teeth, distalization, intrusion, expansion and constriction. They can be applied directly or indirectly to the lingual arch or transpalatal arch. Design modifications using splinted 2 miniscrews have been suggested.

CONCLUSION

Palatal TSADs allow clinicians to perform minimally invasive and easy placement with good stability by understanding the anatomical characteristics of the palatal region, and they show good control over 3-dimensional tooth movements in various clinical cases.

Critical issues concerning biocreative strategy in contemporary temporary skeletal anchorage device orthodontics: A narrative review

Biocreative Orthodontic Strategy (BOS) is designed to establish a physiologically stable occlusion in harmony with masticatory and TMJ function and healthy supporting tissues with strategic use of temporary skeletal anchorage devices (TSADs). This narrative review surveys current research that demonstrates how BOS with TSADs uses a target approach to overcome the limitations experienced with conventional orthodontic treatment. A narrative review article including research on TSADs orthodontics in the permanent dentition. This review is a brief survey of five BOS principles for contemporary TSAD orthodontics: elegant selection of TSADs, bracket prescription to enhance TSAD orthodontics, antero-posterior dimension control, transverse dimension control and airway control issues. Severe malocclusion and craniofacial dysmorphology can be treated with Biocreative Orthodontic Strategy with a minimum number of TSADs. In order to achieve successful treatment outcome using TSADs, it is critical to understand the key diagnosis and treatment principles of BOS and how to develop a target approach for the tooth and bone movement.

Description of a Digital Work-Flow for CBCT-Guided Construction of Micro-Implant Supported Maxillary Skeletal Expander

The introduction of miniscrew-assisted rapid palatal expansion (MARPE) has widened the boundaries of orthodontic skeletal correction of maxillary transversal deficiency to late adolescence and adult patients. In this respect, Maxillary Skeletal Expander (MSE) is a particular device characterized by the engagement of four miniscrews in the palatal and nasal cortical bone layers. Thus, the availability of sufficient supporting bone and the perforation of both cortical laminas (bi-corticalism) are two mandatory parameters for mini-screw stability, especially when orthopedic forces are used. Virtual planning and construction of MSE based on cone-beam computed tomography (CBCT)-derived stereolithography (.stl) files have been recently described in the literature. In this manuscript we described: (a) a user-friendly digital workflow which can provide a predictable placement of maxillary skeletal expander (MSE) appliance according to the patient's anatomical characteristics, (b) the construction of a positional template of the MSE that allows lab technician to construct the MSE appliance in a reliable and accurate position, according to the virtual project planned by the orthodontist on the patient CBCT scans. We also described a case report of an adult female patient affected by skeletal transversal maxillary deficiency treated with MSE appliance that was projected according to the described workflow.