Rapid Maxillary Expansion Group Research Articles

Skeletal effects of posterior crossbite treatment with either quad helix or rapid maxillary expansion: a randomized controlled trial with 1-year follow-up

ABSTRACT Objectives To assess skeletal and dental effects and evaluate possible side effects of maxillary expansion with two different appliances, directly after expansion and 1 year postexpansion. Materials and Methods Forty-two patients with unilateral posterior crossbite (mean 9.5 ± 0.9 years) were randomized to either rapid maxillary expansion (RME) banded on the deciduous second molars and bonded to the primary canines or slow expansion with quad helix (QH) on the permanent first molars. Cone-beam computed tomography records were taken at baseline, directly after correction of the posterior crossbite and at follow-up 1 year after expansion. Results All patients were analyzed. RME opened the midpalatal suture more anteriorly and inferiorly (mean 4.1 mm) and less posteriorly and superiorly (mean 1.0 mm). No effect on midpalatal suture could be shown in the QH group after expansion, P < .001. Buccal bone width had significantly decreased (P < .001) in the QH group compared with the RME group. Buccal fenestrations and root resorption on the left first molar had a higher prevalence directly after expansion finished in the QH group (P = .0086, P = .013) but were not significant at 1-year follow-up (P = .11, P = .22). Conclusions Opening of the suture with RME was more anterior and inferior, and the QH did not open the midpalatal suture at all. More buccal bone loss and fenestrations were seen on the permanent first molar in patients treated with conventional QH than RME anchored to deciduous teeth.

Comparison of the effects on facial soft tissues produced by rapid and slow maxillary expansion using stereophotogrammetry: a randomized clinical trial

ObjectiveTo compare the effects on facial soft tissues produced by maxillary expansion generated by rapid maxillary expansion (RME) versus slow maxillary expansion (SME).Materials and methodsPatients in the mixed dentition were included with a transverse discrepancy between the two arches of at least 3 mm. A conventional RME screw was compared to a new expansion screw (Leaf expander) designed to produce SME. Both screws were incorporated in a fixed expander. The primary outcome was the difference of the facial tissue changes in the nasal area measured on facial 3D images captured immediately before application of the expander (T0) and after one year of retention, immediately after the expander removal (T1). Secondary outcomes were soft tissue changes of other facial regions (mouth, lips, and chin). Analysis of covariance was used for statistical analysis.ResultsFourteen patients were allocated to the RME group, and 14 patients were allocated to the SME group. There were no dropouts. Nasal width change showed a difference between the two groups (1.3 mm greater in the RME group, 95% CI from 0.4 to 2.2, P = 0.005). Also, intercanthal width showed a difference between treatments (0.7 mm greater in the RME group, 95% CI from 0.0 to 1.3, P = 0.044). Nasal columella width, mouth width, nasal tip angle, upper lip angle, and lower lip angle did not show any statistically significant differences. The Y-axis (anterior–posterior) components of the nasal landmark showed a statistically significant difference between the two groups (0.5 mm of forward displacement greater in the RME group, 95% CI from 0.0 to 1.2, P = 0.040). Also, Z-axis (superior-inferior) components of the lower lip landmark was statistically significant (0.9 mm of downward displacement in favor of the RME group, 95% CI from 0.1 to 1.7, P = 0.027). All the other comparisons of the three-dimensional assessments were not statistically significant.ConclusionsRME produced significant facial soft tissue changes when compared to SME. RME induced greater increases in both nasal and intercanthal widths (1.3 mm and 0.7 mm, respectively). These findings, though statistically significant, probably are not clinically relevant.Trial registration ISRCTN, ISRCTN18263886. Registered 8 November 2016, https://www.isrctn.com/ISRCTN18263886?q=Franchi&filters=&sort=&offset=2&totalResults=2&page=1&pageSize=10

Comparison of Rapid Maxillary Expansion and Alternate Rapid Maxillary Expansion and Constriction Protocols with Face Mask Therapy.

This study compared dentoskeletal and soft tissue changes with face mask (FM) therapy. Rapid maxillary expansion (RME) and alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocols were used with the two different types of expansion appliance, and their effects on the treatment outcome were investigated. The study consisted of 79 (37 and 42 patients in the RME and Alt-RAMEC groups with FM, respectively) patients who had received FM treatment. The effects of the RME/FM (20 female, 17 male) and Alt-RAMEC/FM (14 female, 28 male) protocols were evaluated using lateral cephalometric films. The chronological ages of the RME/FM and Alt-RAMEC/FM groups were 11.58 and 11.99 years, respectively. In addition, both groups were divided into two subgroups based on the design of the expansion appliance (Spolyar or full coverage type). Differences in all parameters were analyzed using Student's t-tests. The maxilla significantly moved forward in both the RME/FM and Alt-RAMEC/FM groups (p<0.001). No significant skeletal differences were observed between the groups. Sagittal movement of the upper incisors significantly increased, and the lower incisors significantly retruded in both groups. While similar skeletal changes were found between the Spolyar and full-coverage appliance groups, the upper incisors protruded significantly more in the full-coverage type. RME/FM and Alt-RAMEC/FM therapies were found to be efficient for maxillary protraction and resulted in similar skeletal changes. A full-coverage expansion appliance produced a more upper incisor protrusion than a spherical-type appliance.

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

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). 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. 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. 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).

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

BackgroundThe 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.MethodsPatients 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.ResultsThe 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.ConclusionsAccording 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.

Effect of three different maxillary expansion appliances on root resorption

Aim: The study was to examine rapid maxillary expansion (RME), semi-rapid maxillary expansion (SRME), and slow maxillary expansion (SME) compare the root resorptions occurring in the supporting upper first premolar teeth during treatment by using micro-computed tomography (micro-CT). Methodology: Thirty individuals that required maxillary expansion and upper first premolar tooth extraction were divided into three groups consisting of 10 individuals for RME, SRME, and SME. RME group, first premolar and first molar teeth with hyrax screw were activated ¼ tour twice daily with the banded hyrax appliances. SRME group, acrylic-bonded hyrax appliances were activated ¼ tour per morning and night until the opening of the suture. Upon the opening of the suture, it was activated ¼ tour per every two days until sufficient maxillary expansion was gained. SEM group, quad helix appliances were activated every 20 days. After 12 weeks of the retention period, the upper first premolar teeth were extracted. The teeth were scanned with Micro-CT (SkyScan 1172, Kontich, Belgium), and images were analyzed with a Dell Precision T5500 to determine the resorption crater volumes. Results: In all samples, the resorption craters were concentrated on the buccal surfaces of the tooth roots. The highest resorption craters volume, the total resorption volume, was observed in the RME group, followed by the SRME group, and the least resorption crater volume was detected in the SME group. Conclusion: Since the supporting teeth were exposed to more force on the root surfaces, the most resorption was seen in the RME group. How to cite this article: Topal R, Gündüz Arslan S. Effect of three different maxillary expansion appliances on root resorption. Int Dent Res 2023; 13(1):19-26. https://doi.org/10.5577/idr.2023.vol13.no1.4 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Evaluation of swallowing in transverse maxillary deficiency patients before and after rapid maxillary expansion.

To evaluate swallowing function in relation to oropharyngeal dysphagia (OD) in adolescents who had transverse maxillary deficiency with posterior crossbite and high-arched palate, before, and after rapid maxillary expansion (RME). Twenty patients (mean age: 13.0 ± 3.1) with bilateral posterior crossbite and high-arched palate (RME group: RMEG) and 20 volunteers (mean age: 13.4 ± 2.6) with Class I crowding without posterior crossbite or high-arched palate (control group: CG) were recruited. OD signs and symptoms were evaluated using the Eating Assessment Tool-10 (EAT-10) questionnaire, patient complaints, and physical examination of swallowing function before (T1) and 7 months after (T2) RME. Additionally, fiberoptic endoscopic evaluation of swallowing (FEES) with water, yogurt, and cracker was performed. In CG, evaluation of swallowing was performed only once, corresponding to T1 of RMEG. Prevalence of OD signs and symptoms based on patient complaints and physical examination of swallowing was low (5%-15%), and nonsignificant differences were observed between CG and RMEG at T1 for these parameters as well as for EAT-10 scores. Total post-swallow pharyngeal residue with yogurt was significantly different between CG and RMEG at T1, with a prevalence of 60% in RMEG (P < .05). There was no significant difference regarding residue with yogurt between T1 and T2 in RMEG (P > .05). Patients with a maxillary transverse deficiency were affected by pharyngeal residue as indicated by FEES, but it did not appear to improve in short-term follow-up in patients treated with RME.

Effects of Rapid Maxillary Expansion on Upper Airway Volume in Growing Children: A Three-Dimensional Cone-Beam Computed Tomography Study.

Background: Rapid maxillary expansion (RME) is a common orthodontic procedure that widens the maxillary arch to treat moderate to mild overcrowding and transverse skeletal and dental abnormalities. Orthodontic equipment applies lateral tension on posterior maxilla teeth or palate mucosa to the mid-palatal suture. The maxilla may grow transversely when force is applied at right angles to the mid-palatal suture, which is usually inactive in children and adolescents. This study used cone-beam computed tomography (CBCT) and an authorized upper respiratory airway volume measurement approach to compare RME cohort pharyngeal airway volume changes to healthy controls. Materials and Methods: This retrospective analysis included 52 RME patients and 52 healthy controls. The RME category's expansion regimen entailed twisting the screw of expansion on a tooth-attached Hyrax-type expansion equipment by 0.25 mm daily for at least 14 days. After six months, a few RME participants used fixed orthodontic gear. The comparison group used fixed orthodontic appliances for minor malocclusions without extractions (without RME). CBCT scans from 1021 orthodontic patients who visited a dental hospital between 2012 and 2022 were examined. The registry comprised only anonymized photographs. Volume, minimum cross-sectional area (MCA), molar width, and inter-molar width were measured before and after therapy. Results: The control group had 12227.12 mm3 at T0 and 15805.54 mm3 at T1. The control group's T0-T1 volume difference was statistically significant (p = 0.007). The RME group has 12884.84 mm3 at T0 and 17471.08mm3 at T1. The RME group had a significant volume difference at T0 and T1 (p = 0.002). The volume RME effect was ±1011.92and statistically insignificant. (p > 0.05). MCA in the control group was 126.04 mm2 at T0 and 170.61 mm2at T1. MCA at T0 and T1 in the control group was statistically significant (p = 0.041). RME group MCA was 126.53 mm3 at T0 and 164.69 mm2 at T1. The RME group had a significant volume difference at T0 and T1 (p = 0.002). The MCA, RME effect was 5.92 and statistically insignificant (p > 0.05). Both the control and RME groups had statistically significant volume and MCA differences at T0 and T1. However, the intergroup analysis showed no significant differences across the groups. Conclusion: Tooth-borne RME does not affect upper airway or MCA volume in children compared to controls. Upper airway changes were better with younger skeletal ages before treatment. The findings may aid RME for young children.

Hızlı ve Yarı Hızlı Maksiller Genişletme Etkinliğinin İskeletsel Maturasyon Aşamalarına Göre Karşılaştırılması: Retrospektif Bir Çalışma

Objective: This study aimed to compare the skeletal and dentoalveolar effects of the expansion force created by the semi-rapid and rapid activation protocols. Material and Methods: The study comprised 54 patients (26 female and 28 male) with transverse maxillary insufficiency. Of these patients, 22 were treated with semi-rapid maxillary expansion (SRME) and 32 with rapid maxillary expansion (RME). The SRME group consisted of 6 prepubertal, 8 pubertal, and 8 postpubertal patients, and the RME group consisted of 11 prepubertal, 11 pubertal, and 10 postpubertal patients. Treatment effects with both protocols were evaluated with 11 different measurements on posteroanterior cephalograms and plaster models taken before treatment and after a retention period of 3 months. Kruskal-Wallis analysis was used for comparisons between different maturation periods. Independent sample t-test and Mann-Whitney U test with Bonferroni correction were used for pairwise comparisons between two different activation protocols. Results: The increases in nasal and dental widths in the SRME group were found to be higher than in the RME group in the prepubertal patient group (p0.05). No statistically significant difference was found among prepubertal, pubertal, and postpubertal groups for all skeletal and dental measurements (p>0.05). Conclusion: The current study represented some evidence that the SRME activation protocol might cause less tissue resistance than the conventional RME. The efficiency of maxillary expansion therapy is similar in prepubertal, pubertal, and postpubertal patients in whom sutural resistance is resolved.

Dimensional changes of upper airway after slow vs rapid miniscrew-supported maxillary expansion in adolescents: a cone-beam computed tomography study

BackgroundTo date, the effects of different activation rates of miniscrew-supported expanders on the airway have not been compared. Hence, the purpose of this retrospective study was to evaluate and compare the effects of slow and rapid miniscrew-supported maxillary expansion on the upper airway dimensions using cone-beam computed tomography (CBCT).MethodsData of 20 patients (Age 12 to 16 years old) treated using miniscrew-supported expanders at the Faculty of Dentistry, Alexandria University was collected. The patients were equally divided into two groups according to the activation protocol; slow maxillary expansion (SME): activation once every other day, and rapid maxillary expansion (RME): activation twice daily. CBCT scans obtained pre-expansion and 5 months post-expansion were used to evaluate the changes in the upper airway dimensions. Comparisons between the two time points within each group were done using paired samples t-test. SME and RME groups were compared using independent samples t-test. Significance level was set at p < 0.05.ResultsBoth groups showed a significant increase in anterior, middle, and posterior nasal cavity width. SME resulted in significantly greater increase of the anterior nasal cavity width than RME (Mean difference between the groups, 2.64 mm; 95% CI, 0.83, 4.45; p = 0.007). The dimensions of the retropalatal and retroglossal airways did not change significantly in either group. Both groups resulted in a significant increase of maxillary width, palatal width, and inter-molar width. RME showed a significantly larger increase of inter-molar width than SME (Mean difference between the groups, − 2.44 mm; 95% CI, − 3.88, − 1.00; p = 0.002).ConclusionsThe use of either a slow or rapid activation protocol is effective in expanding the nasomaxillary complex, with greater expansion achieved in the anterior section of the nasal cavity using the slow rate. However, the expander design employed in the current study does not affect the dimensions of the retropalatal or retroglossal airways.

Effect of Maxillary Expansion Treatment Protocols On Maxillary Sinus Volume, Pharyngeal Airway Volume, and Hyoid Bone Position: A Prospective, Cone Beam Computed Tomography (CBCT) Study

Aim: This study aimed to investigate the changes in maxillary sinus volume, pharyngeal airway volume, and hyoid bone position in patients treated with Rapid Maxillary Expansion (RME) and Alternate Rapid Maxillary Expansion and Constriction (AltRaMEC) – Facemask therapy and compare between the groups. Materials and Methods: The records of 15 patients between the age group of 8-14 years with Class I and Class III malocclusion were collected, and the patients were assigned into two groups. The first group comprised of 8patients (4 girls and 4 boys) who were treated with Rapid Maxillary Expansion. The second group comprised 7 patients (5 boys and 2 girls) treated with expansion devices using Alt-RaMEC protocol followed by maxillary protraction using a facemask. Pre and post-treatment CBCT scans were obtained and analyzed for changes in the pharyngeal airway, maxillary sinus volume, and hyoid bone position. The maxillary sinus volume was calculated in 3 dimensions by measuring the craniocaudal height, anteroposterior depth, and mediolateral width. Measurements were taken before and after the procedure to compare the groups and between the groups. The data were analyzed using Paired t-test and an Independent t-test. Results: In the RME group, a significant increase in the total maxillary sinus volume (mean difference = 520±576.57mm3), especially in the craniocaudal height, was seen, but no changes were noted in the pharyngeal airway and hyoid position. The AltRAMEC group showed a statistically significant increase in the maxillary sinus volume (anteroposteriorly) and nasopharyngeal volume with a p-value &lt;0.005. Comparing the maxillary sinus volume changes in RME and AltRAMEC groups showed a statistically significant increase in the volume of the maxillary sinuses in both groups, significantly higher in the RME group. Conclusion: RME and AltRAMEC protocol followed by facemask therapy caused a significant increase in the maxillary sinus volume, while no changes were noted in the nasopharynx, oropharynx, hypopharynx, and hyoid bone position. While comparing the treatment effects between the groups, RME showed a greater increase in maxillary sinus volume (p &lt; 0.05), specifically in the anteroposterior dimension. Since there are no changes in airway volume and hyoid position with the skeletal expansion protocols, there will be no difference in nasal resistance to airflow.

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

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

Evaluation of the Upper Arch Morphological Changes after Two Different Protocols of Expansion in Early Mixed Dentition: Rapid Maxillary Expansion and Invisalign® First System.

Background: The objective of this retrospective study was to analyze the morphological changes of the upper arch after two protocols of expansion, the Invisalign® First system and rapid maxillary expansion (RME), in mixed dentition by means of geometric morphometric analysis (GMM). Methods: Digital dental casts of 32 children treated either with RME (RME group: 17 subjects; mean age 8.1 years) or the First system (First group: subjects; mean age 8.4 years) were collected. For both the RG and FG, pre-(T1) and post-treatment(T2) digital models were created. A total of 14 landmarks were digitized and GMM was applied. Procrustes analysis and principal component analysis (PCA) were performed. Results: The PC1 resulting from the T2–T1 comparison in the RG g showed statistically significant morphological changes in the posterior region of the upper arch shape, without significant variations in the anterior region. The comparison of the T2–T1 changes in the FG showed an increase in the transverse dimension at the level of the canine and the first deciduous molar widths, with morphological variation in the anterior region due to frontal teeth alignment. Conclusions: The First system induced shape modifications of the upper arch during expansion in contrast to RME. The FG presented an improvement in the maxillary arch shape, while the RG maintained the initial triangular shape.

CBCT Analysis of Dento-Skeletal Changes after Rapid versus Slow Maxillary Expansion on Deciduous Teeth: A Randomized Clinical Trial.

The aim of the present study was to compare skeletal and dental changes after rapid maxillary expansion (RME) and slow maxillary expansion (SME) performed by a Leaf Expander (LE) with upper deciduous teeth as anchorage and using 3D CBCT (Cone Beam Computed Tomography) analysis. Mixed dentition patients were randomly divided in two groups, according to the different expansion used anchored on maxillary primary second molars: the RME group (n = 16) was treated with a Hyrax type expander, whereas the SME group (n = 16) was treated with an LE expander. CBCT scans were performed before (T1) and after treatment (T2) and analyzed with a custom landmarks system. A paired t-test was used for intragroup analysis between T1 and T2, and a Student t-test was used for intergroup analysis; statistical significance was set at 0.05. Both RME and SME groups showed a statistically significant increase in dental and skeletal diameters. Group comparisons between T1 and T2 showed a significant expansion rate in the RME group for upper permanent molars (p = 0.025) but not for deciduous molars (p = 0.790). Moreover, RME showed higher increases for skeletal expansion evaluated at nasal walls (p = 0.041), whereas at pterygoid plates did not show any significant differences compared with the SME group (p = 0.849). A significant transverse expansion could be achieved with the expander anchored on deciduous teeth. RME and SME produced effective both skeletal and dentoalveolar transverse expansion; RME produced more anterior expansion than SME but less control regarding the permanent molar decompensation. SME by LE therefore could be an efficient and helpful alternative in the treatment of transverse maxillary deficiency in growing patients.

THE EFFICIENCY OF TOOTH-ANCHORED VERSUS BONEANCHORED RAPID MAXILLARY EXPANSION IN YOUNG AND LATE ADOLESCENT PATIENTS

Relevance of the problem. Incidence of posterior cross­bite has been reported to be 8–23% and it is a com­mon problem often seen in children and adolescents. An effective treatment of the skeletal transversal maxillary deficiency usually involves rapid maxillary expansion (RME). The expansion can be achieved using different types of expanders: bone anchored, tooth anchored or hybrid. The variety of clinical results comparing bone-borne and tooth-borne RME influence lack of unanimous treatment plan for adolescents. Aim. To compare the efficiency of tooth-borne expanders with bone-borne expanders by comparing dentoskeletal changes evaluated by CBCT. Material and methods. Electronic database search was carried out according to PRISMA principles. Five electro­nic research databases were searched including Medline (via PubMed), Cochrane Library, ProQuest, Wiley On­line Library and Web of Science. PICOS framework was used to form a focused question and the risk of bias was assessed using the Cochrane tool for randomized trials (RoB 2) by two individual researchers. Included studies were randomized clinical trials, published less than 10 years ago, with minimum follow-up period of 9 months with CBCT. Results. Two studies proved that bone borne RME produ­ced greater results in skeletal expansion, however other two studies failed to confirm these findings. Regarding alveolar bone loss, the results were also contradictory: two studies found no significant difference in both RME groups, however, other two studies found that bone borne RME exhibit less alveolar bone loss. As for den­tal tipping, the results were also different in all studies: In a study performed by Lagravere et al (2013), dental tipping occurred regardless of RME treatment for molar teeth, however in the premolar group, increased tipping was noticed in the tooth-anchored group. Another study by the same author concluded similar results: in the to­oth borne RME group no significant tipping in molars was seen, while in premolars, buccal crown tipping was observed, which was significant (p&lt;0.003). In the bone borne RME group significant dental tipping was obser­ved in molars. Contrary to these findings, two studies concluded that dental tipping is experienced significantly less in the bone-borne RME group and one study per­formed by Davami et al found no significant difference in both groups. Conclusion. To conclude, current evidence suggests contradictory results in maxillary expansion using bone borne or tooth borne RME devices. Though the evidence is limited, both types of RME have similar outcomes. More studies with a higher number of patients are nee­ded to determine conclusive results.

Three-dimensional palatal morphology and upper arch changes following nonsurgical and surgical maxillary expansion in adults

The objective of this study was to evaluate the effects of nonsurgical rapid maxillary expansion (RME) and surgically assisted RME (SARME) on palatal morphology and upper arch dimensions using three-dimensional (3D) models in skeletally mature patients. Thirty-eight skeletally mature patients with a maxillary transverse deficiency were divided into RME and SARME groups. Nineteen patients in the RME group (mean age, 19.16 ± 2.25 years) were treated using a full-coverage bonded acrylic splint expander; 19 patients in the SARME group (mean age, 20.38 ± 3.36) were treated using the banded palatal expansion appliance with hyrax screws. The 3D models were obtained before and after expansion. The maxillary dental arch widths, maxillary first molar angulation, palatal area, and palatal volume were calculated on the 3D models. All variables showed statistically significant changes after the retention period (P < .001). The maxillary arch width between first premolars (P < .05), the palatal area (P < .01), and the palatal volume (P < .05) significantly increased in the SARME group compared to the RME group. The maxillary first molar tipping in the RME group was significantly higher than that in the SARME group (P < .01). Although SARME has more positive effects in skeletally mature patients, nonsurgical RME can be considered as an alternative by evaluating surgical risks, periodontal status, and the need for skeletal expansion.

Assessment of Patient-Centered Outcomes When Treating Maxillary Constriction Using a Slow Removable Versus a Rapid Fixed Expansion Appliance in the Adolescence Period: A Randomized Controlled Trial.

ObjectiveThis study aimed to evaluate and compare the levels of pain, discomfort, and functional impairments between slow and rapid maxillary expansion (RME) in treating skeletal maxillary constriction in the adolescence period (i.e., between 12 and 16 years).Materials and methodsThe study sample consisted of 52 patients (21 males and 31 females) with maxillary skeletal constriction in the posterior region. The patients were randomly distributed into either RME (26 patients, with a mean age of 13.87 (± 1.31) years) or slow maxillary expansion group (SME, 26 patients, with a mean age of 14.31 (± 1.19) years). The levels of pain, discomfort, and functional difficulties were assessed after 24 hours (T1), 7 days (T2), 15 days (T3), one month (T4), and four months (T5) following the onset of the expansion procedure.ResultsPatients in the RME group encountered significantly greater levels of pain and discomfort than those in the SME group at T1, T2, and T3 (p>0.001). Chewing and swallowing difficulties were significantly greater in the RME group at T1, T2, T3, and T4 (P≤0.001). The pressure on soft tissue was greater in the RME group at T2 and T3 (p>0.001). After four months (T5), the levels of pain and discomfort decreased to their lowest levels, as well as the difficulties of chewing and swallowing, and the pressure on soft tissue were almost non-existent in both groups.ConclusionPatients treated with the removable slow maxillary expander reported lower levels of pain and discomfort, fewer chewing and swallowing difficulties, and less pressure on soft tissues than those treated with the bonded rapid maxillary expander. These difficulties gradually decreased over time in both groups. The lower levels of pain and discomfort may make the SME an effective and comfortable treatment alternative for adolescents with skeletal maxillary constriction.

Intercenter comparison of slow and rapid maxillary expansion in unilateral complete cleft lip and palate.

ABSTRACTObjective: The aim of this study was to compare the occlusal changes of rapid maxillary expansion (RME) and slow maxillary expansion (SME) in patients with unilateral complete cleft lip and palate (UCLP), by means of digital dental models. Methods: Group RME was composed by 22 patients (13 males and 9 females), with mean age of 9.9 years, treated with rapid maxillary expansion with Hyrax appliance in Center 1. Group SME was composed by 29 patients (14 females and 15 males), with mean age of 10.7 years, treated with slow maxillary expansion with quad-helix appliance in Center 2. Digital dental models of the maxillary dental arch were obtained immediately pre-expansion (T1) and 6-month post-expansion (T2). Transversal distances, arch perimeter, arch length, palatal depth, palatal volume and posterior tooth inclination were digitally measured. Interphase and intergroup comparisons were performed with paired t-test and independent t-test, respectively. Results: Intercanine expansion was 4 to 5mm in both groups, and increase in the intercanine distance was similar for both groups. RME group showed a greater increase in arch distances at the region of permanent premolar and molars, compared to SME group. Arch perimeter increase was greater for RME group, compared to SME. No differences were found for arch length, palatal depth, palatal volume and posterior tooth buccal tipping. Conclusion: RME and SME produced similar dentoalveolar outcomes, with greater amount of expansion on RME group.

Effect of methylphenidate at different doses on new bone formation with rapid maxillary expansion: A micro-CT and histomorphometric study in rats.

This study aimed to evaluate the effect of systemically administered methylphenidate hydrochloride (MPH) on new bone formation in premaxillary suture after rapid maxillary expansion (RME). Thirty-three Wistar rats were divided into four groups: Group 1 (high dose, 30/60mg/kg MPH), Group 2 (low dose, 4/10mg/kg MPH), Group 3 (positive control) and Group 4 (negative control). RME was applied on the 70th day of the study. A 5-day RME period was followed by a 12-day retention period. The experiment was terminated on the 87th day. Micro-CT for radiological evaluation, haematoxylin-eosin and Masson's trichrome staining methods were used for histomorphometric evaluation. Among experimental groups with RME, the lowest number of osteoblasts and capillaries in Group 1 (P<.05). New bone formation, fibrous callus formation, distal osteotomy line, proximal osteotomy union and cortex remodelling were observed to be lower in Group 1 and Group 2 than Group 3 (P<.05). There was a statistically significant difference between Group 4 and each of the other groups (P=.000) in the evaluation of the results for bone mineral density, bone volume, bone volume percentage, trabecular thickness and trabecular number. MPH reduces cellular activity for new bone formation in suture in RME groups. Before performing rapid maxillary expansion in patients using MPH, the use of the drug should be postponed after a multidisciplinary decision process or clinical doses should be lowered.

Does rapid maxillary expansion enlarge the nasal cavity and pharyngeal airway? A three-dimensional assessment based on validated analyses.

To evaluate the three-dimensional changes following rapid maxillary expansion (RME) of the nasal cavity (NC) and pharyngeal airway (PA) in growing patients, using innovative and validated evaluation methods and to investigate whether a correlation between skeletal expansion and increase in airway volume exists. Records of patients who had cone beam computed tomography taken before and after orthodontic treatment with or without RME were retrospectively collected and divided into two groups: (a) RME, 39 patients (mean age 10.40±1.74years); and (b) control, 29 patients, matched for age (mean age 11.07±1.45years) and follow-up period. Total and partial volumes of the NC and the PA were calculated. The PA centerline was determined to assess the minimal cross-sectional area and hydraulic diameter. Paired and unpaired t test were applied to compare the difference between time points and between groups. One-way ANOVA and post hoc Tukey's tests were used to compare subgroups with respect to changes in palatal width and lacrimal ducts distance. All of the NC, PA and skeletal parameters were significantly enlarged after RME. The NC volume and inter-molar distance in the RME were significantly larger compared to the control group. The initially lower mean values of minimal cross-sectional area and hydraulic diameter in the RME group when compared to the control group normalized after RME treatment. Based on validated analyses, the NC volume increase was evident after RME in the long term after controlling for growth.