Skeletal and dental changes after maxillary expansion in the mixed dentition

Evaluation of maxillary dimensional changes in the mixed dentition: clear aligners vs acrylic expanders

OBJECTIVES

To compare changes in upper arch dimension and molar inclination between Invisalign First (IF) and removable acrylic expander (RE) treatments during the mixed dentition period.

MATERIALS AND METHODS

Seventeen patients meeting inclusion criteria underwent IF treatment and were age matched with a group that received treatment with a removable acrylic expander (RE). Intercanine width (ICW), intermolar width, arch depth, buccolingual inclination of the first molars (MI), surface area (SA) and volume (VAP) of the anterior palate, and expansion were compared before and after treatment. The predictability of expansion was calculated for the IF group. Analysis of variance and Kruskal-Wallis tests were used to assess differences.

RESULTS

The ICW increased significantly by 2.14 mm in the IF group and 3.49 mm in the RE group, with no significant intergroup difference. Both groups exhibited significant increases in intermolar width (P < .05), except for intermolar distopalatal width in the IF group (P = .246). Mesiobuccal rotation of the first molar was observed with IF treatment. Although SA and VAP increased in both groups, the changes were not significant for the IF group (P > .05). The RE group exhibited significantly higher increases (P < .05), with an SA increase of 34.32 mm2 and VAP increase of 119.15 mm3. MI changes were in the opposite directions. The prediction accuracy of expansion was 70.28% for canines and 34.12% for first molars.

CONCLUSIONS

Both appliances effectively expanded the intercanine region in growing patients. Expansion predictability was lower in first molars than in canines for the IF group. Removable acrylic expanders could be a choice of preference for expansion targeted to the molar region.

Biomechanics of conventional and miniscrew-assisted rapid palatal expansion

Posterior Crossbite is a common condition resulting because of transverse maxillary deficiency. The growth of the craniofacial complex finishes first in the transverse dimension, followed by sagittal and vertical dimensions. Conventional rapid palatal expansion (RPE) appliances are commonly used to correct transverse maxillary deficiency. Although RPE is efficient in correcting posterior crossbite, it results in dental side effects such as buccal tipping of maxillary molars, root resorption, bone dehiscence, and relapse. Mini-implant-assisted RPE has been introduced to increase the skeletal effects of expansion especially in patients with increased maturation and greater interdigitation of midpalatal suture. This article will review the biomechanics of RPE and mini-implant-assisted RPE. Additionally, the different designs of MARPE and the long-term clinical effects of expansion appliances will also be discussed in detail.

Skeletal and dental effects of function-generating bite appliance compared to rapid palatal expander and untreated controls

INTRODUCTION

Maxillary expansion is a fundamental interceptive orthodontic treatment, which can be achieved through either a rapid expansion protocol or functional devices. However, no data exist about the efficacy of functional devices in achieving skeletal expansion. Therefore, the aim of this study was to compare the effects of the rapid palatal expander (RPE) and the function-generating bite type M (FGB-M) on the transversal dimension of the maxilla, and on the maxillary and mandibular dental arch width.

METHODS

One hundred eighty-one skeletal Class I patients, aged between 6 and 12 years and with a cervical vertebral maturation stage II or III, with maxillary transversal deficiency were retrospectively enrolled; among these 55 were treated with FGB-M, 73 were treated with RPE and 51 were untreated subjects retrieved from historical databases. The pre-treatment (T0) and post-treatment (T1) frontal cephalograms were retrieved, and the maxillary and mandibular widths, and the distance between upper and lower first molars were measured. T1-T0 interval was of 17.3 months (RPE), 24.6 months (FGB-M) and 18.2 months (controls).

RESULTS

The statistical analysis showed that there were no statistically significant differences between the RPE and FGB-M groups regarding skeletal and dental expansion, while the untreated control group differed significantly from the other two groups.

CONCLUSION

The comparison between patients treated with RPE and FGB-M showed that there were no statistically significant differences between the RPE and FGB-M groups regarding the amount of skeletal expansion and dental arch width, suggesting that both appliances can be used to achieve similar results.

Comparison of Mechanical Behavior of Clear Aligner and Rapid Palatal Expander on Transverse Plane: An In Vitro Study

(1) Background: This study aims to investigate, within a controlled laboratory environment, the magnitude of the transversal load and the force decay over time produced by clear aligners in comparison to a Rapid Palatal Expander (RPE). (2) Methods: Resin models of a dental maxillary arch, additively manufactured from an intraoral scan, were inserted in a testing machine with uniaxial load cells to measure the force trend over time expressed by RPE and clear aligners. The mechanical load was recorded during a certain timeframe for both appliances. (3) Results: The force expressed by the RPE ranged from 30 to 50 N for each activation, decreasing with a nonlinear pattern over time. The force expressed by the clear aligner ranged from 3 to 5 N, decreasing with a linear pattern over time. In contrast, the force generated by the clear aligner fell within the range of 3 to 5 N, showing a linear reduction in force magnitude over the observed period of time. (4) Conclusions: The RPE exerted a force magnitude approximately ten times greater than that generated by clear aligners. Nevertheless, it is essential to acknowledge that the oral environment can significantly influence these results. These limitations underscore the need for caution when applying these findings to clinical settings.

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

Objective

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

Materials and Methods

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

Results

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

Conclusion

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

Self-perceived pain in Hyrax versus other maxillary expansion orthodontic appliances: a systematic review of clinical studies

PURPOSE

To evaluate self-perceived pain levels in the Hyrax compared to other types of maxillary expansion (ME) appliances in growing patients.

METHODS

An unrestricted search of indexed databases and manual searching were performed up to October 2022. Randomized controlled trials (RCTs) comparing the Hyrax appliance with other ME appliances were included. Data screening, extraction, and Risk of Bias (RoB) assessment with the Cochrane tool were performed by two authors.

RESULTS

Six RCTs were included. The number of participants in the included RCTs ranged between 34 to 114 and included both male and female growing patients. Various tools were used to measure self-perceived pain including the Graphic Rating Scale for Pain, the Wong-Baker Faces Pain Scale, the Numerical Rating Scale, the visual analogue scale, and a questionnaire. One RCT reported that pain intensity in patients treated with the Hyrax was higher than in the Haas appliance, with a statistically significant difference limited to the first day. Two RCTs reported that pain intensity in patients treated with the Leaf expander was lower than in the Hyrax during the first 7 days of treatment. Two RCTs reported no significant differences in pain intensity between the Hyrax and other ME appliances. One RCT reported that pain intensity in patients using the computer-guided skeletal ME appliance was higher than in the Hyrax appliance at the first day after expansion. Four RCTs had a high RoB, and two RCTs had a moderate RoB.

CONCLUSIONS

Within the limitations of the present systematic review and based on the currently available evidence, it is challenging and inconclusive to identify the best maxillary expansion appliances, regarding pain levels for growing patients.

Long-term effects of orthodontic interceptive expansion treatment : A retrospective study

PURPOSE

The aim of this retrospective cohort study was to evaluate the long-term effects of interceptive orthodontic treatment with a removable expansion plate, based on transversal, sagittal, and vertical parameters.

METHODS

A total of 90 patients needing interceptive treatment due to a crossbite or space deficiency were included. Records consisting of clinical photos, radiographs, and digital dental casts were collected for evaluation at two time points: the start of interceptive treatment (T0) and the start of comprehensive treatment (T1). Molar occlusion, overjet, overbite, presence and type of crossbite, mandibular shift, and transversal measurements were recorded for comparison.

RESULTS

After expansion with removable appliances, a significant increase in intermolar width was achieved and could be maintained over the observation period (p < 0.001). However, no significant changes regarding overjet, overbite, or molar sagittal occlusion were observed. Crossbite correction was successful in 86.9% of patients with unilateral crossbite and in 75.0% of patients with bilateral crossbite (p < 0.001).

CONCLUSION

Early expansion with a removable expansion plate is a successful method to correct crossbites and increase intermolar width in the early mixed dentition phase. Results remain stable until the start of comprehensive treatment in the permanent dentition.

Dentoskeletal effects of rapid maxillary expander therapy in early mixed dentition patients with different vertical growing patterns without posterior crossbite: A retrospective study

INTRODUCTION

This study aimed to analyze the variation of dentoskeletal effects after rapid maxillary expander therapy in subjects with different vertical growth patterns.

METHODS

The study sample consisted of 94 patients (32 males, 62 females; mean age 8.9 ± 1.5 years) treated with rapid maxillary expander (RME) anchored on first permanent molars. For each subject, lateral cephalograms and maxillary digital dental casts were available before RME, immediately after appliance removal, and 1 year after appliance removal. All the subjects were divided into 3 groups according to their vertical facial patterns (low-angle, normal-angle, and high-angle). Cephalometric analysis was conducted on lateral cephalograms. The virtual 3-dimensional models were used to analyze the torque of the first permanent molars and intercanine and intermolar width. The differences between the vertical facial subgroups were contrasted by analysis of variance multicomparison test (P <0.05).

RESULTS

In the short-term (from before to immediately after RME removal), high-angle subjects showed a mandibular clockwise rotation compared with other groups. No significant long-term vertical and sagittal skeletal changes (from before to 1 year after RME removal) were found between the groups. A greater increase in maxillary molar torque was observed in high-angle subjects than in the other groups. The low-angle patients showed a greater increase in the intercanine diameter.

CONCLUSIONS

Hyperdivergent subjects showed increased buccal tipping of the anchor molars after the expansion. Hypodivergent and normodivergent subjects showed lower buccal tipping after the expansion and an increased expansion effect in the anterior region.

Evaluation of the Changes of the Intercanine and Intermolar Widths Following Palatal Expansion in the Mixed Dentition Patients with Bilateral Posterior Crossbite: A Systematic Review

This systematic review aimed to identify the intercanine and intermolar width changes following palatal expansion in bilateral posterior crossbite (PXB) in mixed dentition. This review was registered in the PROSPERO database (CRD42021275833). All randomized controlled trials (RCT) and non-RCT articles between 1980 and August 2022 on the palatal expansion of bilateral PXB in mixed dentition were searched in seven online databases (Google Scholar, Ovid, Web of Science, Scopus, EBSCOHost, Cochrane Library and PubMed). The risk of bias (RoB) of the articles included was analyzed using the Joanna Briggs Institute (JBI) critical appraisal tool. Three non-RCT studies were included and showed a low risk of bias. Meta-analysis on the changes in intercanine and intermolar widths was not performed due to study design heterogeneity. One study reported an over-correction of the bilateral PXB. There is a need for more RCT studies with standardized landmark measurements, outcome assessment methods and retention periods to investigate the interdental changes following palatal expansion.

Midpalatal Suture Maturation Method for the Assessment of Maturation before Maxillary Expansion: A Systematic Review

Assessment of midpalatal suture maturation is crucial before deciding which type of maxillary expansion technique will be performed to treat transverse discrepancies. In 2013, Angelieri et al. proposed a new method to evaluate midpalatal maturation using cone-beam computed tomography. The aim of this study was to systematically identify, evaluate, and provide a synthesis of the existing literature about this new method and to rigorously assess the methodological quality of these articles. A bibliographic search was carried out using PubMed, Cochrane Library, SciELO, LILACS, Web of Science, and Scopus using the terms midpalatal suture, cranial sutures, palate, maturation, interdigitation, ossification, maxillary expansion, evaluation, assessment, and assess. Quality assessment was performed using the Observational Cohort and Cross-Sectional Studies tool developed by the National Heart, Lung, and Blood Institute. Hence, 56 articles were obtained, of which only 10 met the selection criteria. We could not include any of the data into an analysis because of the large variation of the data collected and high methodological heterogeneity found among studies. Of all the studies included, 10% had poor quality, 70% fair, and 20% good quality, respectively. Even though age and sex play a role in midpalatal suture obliteration, there is a poor correlation between these variables. Thus, every patient should be assessed individually before choosing the best protocol for maxillary expansion. The midpalatal suture maturation method has the potential to be used for diagnostic purposes, but clinicians should be cautious of routinely using it because an extensive training and calibration program should be performed prior.

Changes in the Mandible Following Rapid Maxillary Expansion in Children with Class II Malocclusion: A Systematic Review

Objective: The aim of this systematic review was to determine whether rapid maxillary expansion (RME) allows favorable changes in the mandible during the treatment of class II malocclusion before the growth spurt. Methods: A search of Pubmed/Medline, the Science Direct, and the Google Scholar database was performed. The keywords used were: orthodontics, rapid maxillary expansion, class II, and growing patients. Relevant articles were assessed for quality according to Cochrane guidelines, and then changes in SNA, SNB, ANB, NL-NSL (or SN-SNP.SNA), and ML-NSL (or SN-Go-Gn) relationships were analyzed. Results: The selection process brought forth five articles, including 162 patients (91 females, 71 males) for detailed analysis. The quality of the evidence (GRADE) for comparisons and outcomes was assessed as moderate for SNB and ANB and as low or very low for other variables. Conclusions: The results of this systematic review showed that there is a small body of moderate-quality evidence for statistically and clinically favorable changes in SNB and ANB angles and a small body of low-quality evidence for changes in vertical parameters after RME.

Differences in dentoskeletal and soft tissue changes due to rapid maxillary expansion using a tooth-borne expander between adolescents and adults: A retrospective observational study

Objective

The purpose of this study was to compare the differences in dentoskeletal and soft tissue changes following conventional tooth-borne rapid maxillary expansion (RME) between adolescents and adults.

Methods

Dentoskeletal and soft tissue variables of 17 adolescents and 17 adults were analyzed on posteroanterior and lateral cephalograms and frontal photographs at pretreatment (T1) and after conventional RME using tooth-borne expanders (T2). Changes in variables within each group between T1 and T2 were analyzed using Wilcoxon signed-rank test. Mann–Whitney U test was used to determine the differences in the pretreatment age, expansion and post-expansion durations, and dentoskeletal and soft tissue changes after RME between the groups. Spearman’s correlation between pretreatment age and transverse dentoskeletal changes in the adolescent group was calculated.

Results

Despite similar amounts of expansion at the crown level in both groups, the adult group underwent less skeletal expansion with less intermolar root expansion after RME than the adolescent group. The skeletal vertical dimension increased significantly in both groups without significant intergroup difference. The anteroposterior position of the maxilla was maintained in both groups, while a greater backward displacement of the mandible was evident in the adult group than that in the adolescent group after RME. The soft tissue alar width increased in both groups without a significant intergroup difference. In the adolescent group, pretreatment age was not significantly correlated with transverse dentoskeletal changes.

Conclusions

Conventional RME may induce similar soft tissue changes but different dentoskeletal changes between adolescents and adults.

The effectiveness of the early orthodontic correction of functional unilateral posterior crossbite in the mixed dentition period: a systematic review and meta-analysis

Objective

This systematic review and meta-analysis aimed to critically appraise the available evidence of the effectiveness of early intervention of functional unilateral posterior crossbites (FPXB) between the ages of 6 and 12 years.

Materials and methods

Electronic search in four databases (PubMed, Scopus, Embase, and Google Scholar) for randomized controlled trials (RCTs) and controlled clinical trials (CCTs) was performed between 1^st January 1990 and 31^st October 2021. Methodological index for non-randomized studies (MINORS) for CCTs and Cochrane's risk of bias tool for RCTs were applied. The certainty of the evidence was evaluated according to the grading of recommendations, assessment, development, and evaluation (GRADE) approach.

Results

Nine studies (6 RCTs and 3 CCTs) were included in this review, and six of them were appropriate for quantitative synthesis. The meta-analysis revealed that the quad-helix (QH) was more effective than expansion plates (EP) in increasing the intermolar width (WMD = 1.25; 95% CI 0.75, 1.75; P < 0.001), and decreasing treatment time (WMD = − 3.36; 95% CI − 4.97, − 1.75; P < 0.001). The relapse rate at 5.6 years post-treatment was greater in the QH group than in the EP group (RR = 3.00); however, the difference was statistically insignificant. There was no significant difference between the QH and the EP in other outcome measures. When assessing the rapid maxillary expansion (RME), only one RCT compared the RME with an untreated control group and reported a significant increase in the maxillary intermolar and intercanine width (P < 0.001, P = 0.002, respectively) and a significant decrease in lower midline deviation (P < 0.001).

Conclusion

There is weak to moderate evidence that the treatment of functional posterior crossbite (FPXB) by the QH increased the maxillary intermolar width and the success rate and decreased the treatment duration compared to the EP. The relapse percentage was greater in the QH group. There is very weak evidence that the mandibular midline correction rate did not differ significantly between the QH and the EP modalities. The RME using the Hyrax appliance corrected the FPXB successfully; however, the strength of evidence in this regard is very low. As the quality of evidence ranged from very low to moderate in this review, we confirm the need for more RCTs with different expansion appliances in the early treatment of FPXB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40510-022-00398-4.

Post-Expansion and end of treatment outcomes of semi-rapid maxillary expansion with a modified removable appliance

Context

Maxillary expansion is the mainstay therapy for maxillary transverse deficiency. There has been a constant search for the most effective yet biologically friendly method of maxillary expansion, alternatives being, slow, rapid and semi rapid.

Aims

The purpose of this study was to explore the outcome of palatal expansion achieved using a removable plate and low continuous forces brought about by a semi rapid screw activation protocol.

Settings and Design

Retrospective study.

Methods and Material

Plaster models of 56 consecutive patients treated for maxillary expansion were obtained pre-treatment (T₀), post-expansion (T₁), and post fixed appliance treatment (T₂). The radiographic images of the models were traced using Image J software. Linear and angular measurements were evaluated to measure transverse change.

Statistical Analysis Used

Interclass Correlation Coefficient [ICC] and Dahlberg's formula were used for reliability test. The differences in the mean values between the three duration groups [T₀, T₁ and T₂] were analysed using Analysis of Variance (ANOVA). For multiple comparisons, a post hoc Tukey honestly significant difference (HSD) test was performed.

Results

Significant increase in inter-molar, alveolar and palatal linear widths were observed from T₀ to T₁ with significant relapses from T₁ to T₂, with an overall net gain remaining at T₂. Similarly, significant increases in all angular measurements were observed from T₀ to T₁ with significant relapses from T₁ to T₂ and an overall insignificant change at T₂ as compared to T₀.

Conclusion

The appliance and protocol were effective in producing transverse expansion with minimal molar and alveolar tipping.

Effects of rapid and slow maxillary expansion on root resorption: a micro-computed tomography study

AIM

To compare root resorption (RR) after rapid maxillary expansion (RME) and slow maxillary expansion (SME) through micro-computed tomography (micro-CT).

SUBJECTS AND METHODS

Twenty-six subjects who required maxillary expansion and bilateral upper first premolar extraction were randomly assigned to RME (n = 13, mean age: 13.25 ± 0.88 years) or SME (n = 13, mean age: 13.53±1.28 years) group. A hyrax-type acrylic bonded expansion appliance was used. The Hyrax screw was activated ¼ turn twice a day for 20 days in the RME group and ¼ turn every second day for 80 days in the SME group. One randomly selected upper first premolar was extracted in each patient after active expansion. The appliance was left in situ for a 24-week retention period then the contralateral upper first premolar was extracted. Extracted teeth were scanned with micro-CT and the volume of the resorption craters was analysed with a specialized software. Transversal skeletal and dental widths were measured on posteroanterior radiographs taken before and after expansion and retention periods.

RESULTS

The resorption craters were concentrated mostly on the buccal surface and middle level in all samples. The total RR in the RME group was less post-expansion (P ≤ 0.05) and more post-retention (P > 0.05) than the SME group. During retention, there was a significant decrease in the total RR in the SME group (P > 0.05) and an increase in the RME group. Both RME and SME groups displayed a similar increase in skeletal transverse dimensions, but inter-molar width increased significantly more in the SME group during the whole experimental period.

CONCLUSION

RME does not have an advantage over SME in terms of skeletal expansion and the amount of RR when a retention period of six months is followed.

Effect of microimplant assisted rapid palatal expansion on bone-anchored maxillary protraction: A finite element analysis

INTRODUCTION

This study aimed to evaluate the craniofacial effects of microimplant assisted rapid palatal expansion (MARPE) on bone-anchored maxillary protraction (BAMP) through a finite element analysis.

METHODS

A 3-dimensional finite element model of the skull with associated sutures was created from the computed tomography image of a 12-year-old male patient. Two protraction protocols: BAMP without MARPE (protocol 1) and BAMP with MARPE (protocol 2), were analyzed using Ansys software (Ansys, Canonsburg, Pa). Stress distribution in the sutures and displacement pattern of craniofacial structures were analyzed in the 2 protocols using finite element analysis.

RESULTS

Both protocols produced changes in craniofacial structures in all the 3 planes. Displacement of the maxilla was more pronounced in protocol 2 in all directions with mild clockwise rotation. Protocol 1 displayed a translatory movement of the maxilla without any rotation and mild constriction in the anterior region. In protocol 2, an expansion of the maxilla, which increased in the superoinferior direction, was also observed. Von Mises stress in circummaxillary sutures was significantly more in protocol 2, indicating an increased displacement of craniomaxillary structures.

CONCLUSIONS

The use of MARPE during BAMP enhanced maxillary protraction and reduced the counterclockwise rotation tendency of the maxilla. Hence, it may be inferred that incorporation of MARPE during BAMP protocol may prove beneficial in the treatment of patients with skeletal Class III malocclusion with open bite tendency or hyperdivergent growth pattern.

Short term effects of interceptive expansion treatment: a prospective study

OBJECTIVES

This prospective cohort study investigated the short term effects of interceptive orthodontic treatment with a removable expansion plate, evaluating the changes in occlusion in all its dimensions: transversal, sagittal and vertical.

SUBJECTS AND METHODS

A total of 226 patients treated with a removable expansion plate (slow maxillary expansion, SME) by orthodontic residents at the Department of Orthodontics, University Hospitals Leuven, Belgium were included. The patients had a mean age of 8.5 years at the start of the treatment. The mean treatment time was 6.9 months. Transversal measurements (intercanine and intermolar width) and occlusal characteristics (molar occlusion, overjet, overbite and functional shift) were collected before (T0) and after active treatment (T1). Statistical analysis was performed using the Wilcoxon signed rank test, Sign test and McNemar test for assessing changes between T0 and T1. Linear models were used to assess the associations between patient factors and the amount of expansion.

RESULTS

A significant increase in transversal width at different occlusal landmarks was found. Correction of unilateral, bilateral and frontal crossbites was successful in 99.0%, 95.2% and 93.6% of the cases respectively. Changes in sagittal molar occlusion were significant: 64.9% (right side) and 62.6% (left side) remained stable, 28.4% (right) and 29.3% (left) improved and 6.7% (right) and 8.1% (left) deteriorated. Overbite changes were found to be statistically significant, though clinically irrelevant. Overjet changes were non-significant.

CONCLUSIONS

A removable expansion plate is successful in improving the transversal dental dimensions of the maxilla. Statistically significant sagittal effects on molar occlusion were found. Long-term follow-up is needed to evaluate the long-term stability of this treatment.

Mechanical Tension-Stress in Alveolar Cleft Repaired With Autogenous Bone in Canine Models

OBJECTIVE

Cleft lip and/or palate is a common birth defect worldwide, always accompanied by alveolar cleft. However, the success rate of secondary alveolar bone grafting is unsatisfactory. Rapid maxillary expansion (RME) often used after bone transplantation provides functional stimulation for bone graft area. This study aimed to investigate the effect of RME force on the bone graft area and midpalatal suture, and screen out the most suitable loaded force and loaded teeth, so as to provide a reference for clinical treatment.

METHODS

Fourteen 24-week-old male beagles were assigned randomly to 3 groups: blank control, autogenous, and autogenous with RME. Three-dimensional finite element analysis was conducted to evaluate the distribution and value of the stress in the model. The maxillae were collected and subjected to radiography and helical computed tomography to evaluate new bone formation in the graft area. Van Gieson's Picrofuchsin staining was performed for histomorphological observation.

RESULTS

After 8 weeks of RME treatment, new bone formation of the dogs was markedly accelerated, and bone resorption was significantly reduced compared with the untreated dogs or those only treated with autogenous iliac bone. The treatment with RME evidently made the bone trabecula more abundant and the area of bone formation larger. Three-dimensional finite element analysis showed that the clinical effect can be achieved by using canine teeth as the loaded teeth and applying force of 10 MPa.

CONCLUSION

Rapid maxillary expansion after bone grafting had a positive effect on osteogenesis in a canine model of alveolar cleft.

A postero-anterior cephalometric evaluation of different rapid maxillary expansion appliances

BACKGROUND

The purpose of the study was to evaluate dental and skeletal changes induced by tooth-bone-borne, tooth-tissue-borne, and tooth-borne rapid maxillary expansion (RME) appliances using postero-anterior (PA) cephalometric radiographs.

METHODS

A total of 54 patients' (25 boys, 29 girls) PA cephalometric radiographs who had bilateral posterior crossbite and RME treatment were included and divided into three groups according to the type of appliance used during treatment: tooth-bone-borne RME appliance (hybrid Hyrax) (7 boys, 11 girls, mean age 13.28 ± 1.20 years), tooth-tissue-borne RME appliance (TTB) (8 boys, 10 girls, mean age 13.08 ± 1.06 years) and tooth-borne RME appliance (Hyrax) (10 boys, 8 girls, mean age 12.05 ± 1.35 years). Pretreatment (T0) and posttreatment (T1) PA cephalometric radiographs were analyzed with Dolphin software v. 11.7 (Chatsworth, CA). The comparisons of the groups were performed with Two-way analysis of variance. P < 0.05 was considered statistically significant.

RESULTS

Significant and equal increase of right molar relationship and upper intermolar molar widths occurred in all groups. Dental midline discrepancy showed significant increase in only hybrid Hyrax group between T0 and T1. Significant increases were reported for lateronasal width in hybrid Hyrax and tooth-tissue-borne groups (P < 0.05).

CONCLUSIONS

Both skeletal and dental changes were observed after RME in all groups. However, the greatest skeletal changes were seen in hybrid Hyrax and tooth-tissue-borne groups.

Three-dimensional morphological and positional analysis of the temporomandibular joint in adults with posterior crossbite: A cross-sectional comparative study

OBJECTIVES

The purpose of this study was to three-dimensionally (3D) evaluate the morphological and positional features of the temporomandibular joint (TMJ) in adults with unilateral and bilateral posterior crossbite compared with aligned control subjects.

MATERIALS AND METHODS

This cross-sectional comparative study analysed cone beam computed tomography (CBCT) images of 90 adult subjects' divided into three equal groups: bilateral posterior crossbite (BCG), unilateral posterior crossbite (UCG) and control group (CG). 3D measurements of the TMJ included the following: (a) position, angulation and inclination of the mandibular condyles; (b) centralisation of the condyles in their respective mandibular fossae; and (c) volumetric measurements of the TMJ spaces. Intra- and intergroup differences were identified using the paired Student's t test and an analysis of variance (ANOVA) followed by Tukey's post hoc test, respectively.

RESULTS

Regarding the intra-group side-based comparisons, there were significant differences in the anterior and superior joint spaces and the anteroposterior condylar joint position in the UCG. Intergroup comparisons revealed significant differences in the vertical condylar inclination, medial condylar position, condylar width and height, and volumetric joint space between the unaffected side of the UCG and left sides of the other groups. There were significant differences in the anteroposterior condylar inclination, medial condylar position, condylar width and height, anterior, posterior, superior and volumetric joint spaces, and anteroposterior condylar joint position between the crossbite side of the UCG and the right sides of the other groups.

CONCLUSION

Skeletal crossbite accompanied with characteristic morphological and positional TMJ features associated with unilateral posterior crossbite and are associated with side-specific TMJ asymmetry.

Effects of bicortical anchorage on pterygopalatine suture opening with microimplant-assisted maxillary skeletal expansion

INTRODUCTION

The objectives of this study were to evaluate the effects of bicortical engagement by microimplants with maxillary skeletal expanders on pterygopalatine sutures opening and to analyze the postexpansion skeletal changes associated with it.

METHODS

Eighteen subjects treated with maxillary skeletal expanders were examined for pterygopalatine suture openings. Eight subjects who showed no evidence of the suture opening were assigned to the nonsplit group (NG), whereas 10 subjects with opened sutures were assigned to the split group (SG). Preexpansion and postexpansion cone-beam computed tomography images were superimposed for each group, and the changes in the 2 groups were compared. Finally, cone-beam computed tomography volumes were reoriented along the axis of each microimplant to check the bicortical engagement of the 4 microimplants.

RESULTS

There was a significant correlation between the bicortical engagement of the orthodontic microimplants and the pterygopalatine suture opening (P = 0.0003). In the NG, the average amount of transverse expansion measured at the center of resistance of the maxillary first molars, anterior nasal spine, and posterior nasal spine (PNS) was 4.33 mm, 2.22 mm, and 1.58 mm, respectively, whereas the transverse expansion in the SG was 5.29 mm, 2.21 mm, and 2.46 mm, respectively. The magnitude of transverse expansion at PNS was significantly higher in the SG than in the NG (P = 0.036). The PNS also showed a significant anterior displacement in the SG (0.89 mm) compared with the NG (0.06 mm) (P = 0.033).

CONCLUSIONS

Bicortical microimplant anchorage is essential for pterygopalatine suture opening in microimplant-assisted maxillary skeletal expansion, which may result in further skeletal expansion and forward movement in the posterior part of the palatomaxillary complex.

A randomized clinical trial to assess the sagittal effects of Transforce transverse appliance (TTA) and NiTi palatal expander (NPE) on skeletal class II malocclusion in growing patients during retention phase - A cephalometric study using a historical control group

OBJECTIVES

To evaluate and compare the skeletal changes during the retention period after expansion with "Transforce Transverse lingual or palatal Appliance®" (TTA) and "NiTi Palatal Expander®" (NPE) in growing subjects with class II division 1 malocclusion and to compare these changes with a matched historical control.

SUBJECTS AND METHODS

A unicentric two arm, parallel randomized clinical trial with additional historical control group was conducted over a period of six years. The subjects in the age group of 9-13 years were screened and recruited as they reported. The inclusion criteria were: late mixed/early permanent dentition, class II or end on molar relationship, posterior transverse inter-arch discrepancy 4-8mm, overjet≥5mm, cephalometrically ANB>4° and CVMI stage CS2-CS3. Subjects were randomly allocated to two study groups (SG), TTA and NPE using block randomization. Appliances in both SG were managed and followed by a single clinician with equal standards of care. The lateral cephalograms in digital form were obtained at the beginning of the treatment (T1), post-expansion (T2) and after ten months retention period (T3). Linear positional change>1mm and angular change>0.75° were considered as a clinically significant change. Due to the ethical reasons a historical control of ten patients (CG) comparable to the SG for age and inclusion criteria was used to rule out the growth changes on serial lateral cephalograms. All Cephalometric measurements were done by a single operator blinded for the group allocation. Operator's measurement error was estimated. The study was single-blinded in regard to statistical analysis. Inter-group comparisons between SG were made by using an unpaired Student's t-test. ANOVA with post-hoc analysis was used for comparison among the study and control groups.

RESULTS

A total of 36 subjects were recruited, 18 in each SG. Average time required to achieve the desired expansion in the TTA and NPE group was 13.6 weeks and 9.8 weeks respectively. The TTA group showed significant increase in SNB (1.54±0.33°) when compared with the control group (0.53±0.37°) and with the NPE group (0.74±0.29°) (P<0.0001). Significant differences were observed when post-retention changes in SNB, ANB, Wits appraisal, and N perpendicular to Pogonion, were compared among the three groups (ANOVA, P<0.0001). Tukey's multiple comparison showed that these mandibular sagittal changes were significantly greater in the TTA group than in NPE and the control group (P=<0.007, Bonferroni corrected value).

CONCLUSION

Cephalometrically significant sagittal advancement of mandible took place after expansion with TTA and NPE compared to untreated control. TTA appears to be more efficient for the sagittal positional changes than the NPE. Additional studies with larger samples are warranted to elucidate individual variations in skeletal response to the expansion protocol with these appliances.

A preliminary 3-D comparison of rapid and slow maxillary expansion in children: A randomized clinical trial

BACKGROUND

This study compared the effects of rapid maxillary expansion (RME) and slow maxillary expansion (SME) using cone-beam computed tomography (CBCT).

AIM

To evaluate the skeletal and dentoalveolar effects produced by two different maxillary expansion protocols.

DESIGN

Eligibility criteria included maxillary transverse deficiencies in children (mean age, 8.18 years old), randomly assigned to either RME or SME. At the outcome analysis phase, a sample of 29 subjects were analysed (RME group, N = 16 and SME group, N = 13). CBCT scans taken before expansion and 6 months later were evaluated. Five posterior and 6 anterior transverse measurements were made at different vertical levels. Treatment changes were analysed using paired t tests; independent t tests were used to compare the two groups.

RESULTS

There were statistically significant (P<.05) increases in maxillary width at the skeletal, alveolar, and dental levels for both groups, with significantly smaller increases at the more superior than inferior levels. The RME group exhibited statistically larger width increases than the SME group for all measures except interorbital width, anterior alveolar process width, and intercanine width. The group differences were greater for anterior than posterior apical base widths.

CONCLUSIONS

Rapid maxillary expansion produced greater orthopaedic effects than slow maxillary expansion, with the greatest effects occurring in the anterior apical base.

Three-dimensional changes of the zygomaticomaxillary complex after mini-implant assisted rapid maxillary expansion

INTRODUCTION

The aim of this study was to investigate 3-dimensional changes of the zygomaticomaxillary complex (ZMC) after mini-implant assisted rapid maxillary expansion (MARME).

METHODS

A total of 15 pairs of cone-beam computed tomography 3-dimensional images taken before expansion (T0) and after expansion (T1) were analyzed by measuring changes in the coordinates of the landmarks of the ZMC.

RESULTS

Changes in the x coordinates of the landmarks showed significant expansion (P <0.01) and greater expansion at the lower than upper portion of the ZMC (P <0.05) in the transverse dimension. All y coordinates of the landmarks except the jugal point (J) showed forward displacement (P <0.05), and the z coordinates of ANS, PNS, Alare, A, and ectocanine showed downward displacement (P <0.01) in the sagittal and vertical dimensions. Also, z coordinates of the landmarks that were closer to the midsagittal plane and in a more posterior portion of the ZMC displaced further downward (P <0.05). SNA and ANB angles increased (P <0.05 and P <0.001, respectively) and the SNB angle decreased (P <0.01). There was a significant correlation between changes in the x coordinates of the ectomolare and ectocanine and the amount of expansion measured from the center of resistance of the maxillary first molars (CR6; P <0.05). There was no significant correlation between the amount of CR6 expansion and changes in y and z coordinates of the landmarks.

CONCLUSIONS

3-Dimensional changes of the ZMC after MARME showed expansion in a pyramidal shape from the coronal view, downward and forward displacement from the sagittal view, and parallel palatal expansion from the axial view. These findings might be useful for understanding skeletal expansion patterns using MARME.

Periodontal side effects of rapid and slow maxillary expansion: A systematic review

OBJECTIVES

To identify the scientific evidence that demonstrates which of the transverse maxillary treatments has the least effect on periodontal tissues.

MATERIALS AND METHODS

PubMed (MEDLINE), Cochrane Library, Scopus, Web of Science, Virtual Health Library, Google Scholar, and OpenGrey were searched without restrictions. A hand search was also carried out in the reference lists of the articles selected. The related articles tool in the PubMed database was checked for each article included. Risk of bias assessment was performed using Cochrane Collaboration's Risk of Bias tool for randomized clinical trials and the ROBINS-I tool for nonrandomized studies of interventions. The GRADE tool was used to assess the quality of the evidence.

RESULTS

After examination of the full texts, three studies were finally included. Two studies used a Haas expander with different protocols, and one study used a Haas expander compared with a quad-helix appliance. These studies evaluated periodontal parameters and periodontal indices by clinical examination with a millimeter probe, and one study examined computed tomography images. After quality assessment, two studies were considered as having a "low" risk of bias. One study was scored as having a moderate risk of bias. The evidence was graded as moderate quality for alveolar bone level, tooth displacement, and inclination and very low for all other outcomes.

CONCLUSIONS

There were no significant differences to enable a sound conclusion about which type of maxillary expansion has the least periodontal side effects.

Retention period after treatment of posterior crossbite with maxillary expansion: a systematic review

OBJECTIVE:

The aim of this systematic review was to evaluate the duration of the retention period in growing patients undergoing maxillary expansion and its relation with posterior crossbite stability.

METHODS:

Search strategies were executed for electronic databases Cochrane Library, Web of Science, PubMed and Scopus, which were completed on January 15, 2016. The inclusion criteria included randomized, prospective or retrospective controlled trials in growing subjects with posterior crossbite; treated with maxillary expanders; retention phase after expansion; post-retention phase of at least 6 months. The exclusion criteria were anterior crossbite, craniofacial anomalies, surgery or another orthodontic intervention; case reports; author’s opinions articles, thesis, literature reviews and systematic reviews. The risk of bias of selected articles was assessed with Cochrane risk of bias tool for RCTs and Downs and Black checklist for non-RCTs.

RESULTS:

A total of 156 titles/abstracts was retrieved, 44 full-texts were examined, and 6 articles were selected and assessed for their methodological quality. The retention period after maxillary expansion ranged between 4 weeks and 16 months. Fixed (acrylic plate, Haas, Hyrax and quad-helix) or removable (Hawley and Hawley expander) appliances were used for retention.

CONCLUSIONS:

Six months of retention with either fixed or removable appliances seem to be enough to avoid relapse or to guarantee minimal changes in a short-term follow-up.

Skeletal changes following surgically assisted rapid maxillary expansion (SARME)

Purpose

Surgically assisted rapid maxillary expansion (SARME) is a common treatment technique in the correction of maxillary transverse deficiency. The purpose of this study was to evaluate nasal and palatal skeletal changes following SARME using Cone Beam Computed Tomography (CBCT) and posterior anterior (PA) cephalograms.

Materials and Methods

In this retrospective study, the radiographic images obtained from 14 patients with transverse maxillary deficiency before treatment and 6 months after SARME operations were evaluated. The changes in nasal bone width and palatal bone width were measured on CBCT. The changes in basal maxillary width, nasal cavity width and angular measurements were evaluated on PA cephalograms.

Results

Nasal floor width was measured at the levels of upper first premolar teeth and molar teeth which significantly increased following SARME (p=0.005 and 0.017 respectively). Palatal bone width between first premolar teeth and molar teeth also significantly increased (p=0.003 and 0.002 respectively). Basal maxillary width (p=0.026), nasal cavity width (p=0.024) and other angular measurements also significantly increased (p<0.05).

Conclusion

Nasal and palatal skeletal transverse dimensions increased following SARME. Due to the enlargement of the nasal floor and nasal cavity, it is likely to improve air pass through the nose.

Facial soft tissue changes after nonsurgical rapid maxillary expansion: a systematic review and meta-analysis

Background

The present systematic review and meta-analysis aimed to test the hypothesis that no facial soft tissue changes occur after nonsurgical rapid maxillary expansion (RME), in order to provide a reference for orthodontists.

Methods

PubMed, EMBASE, Cochrane Library, OVID, MEDLINE, CINAHL, Scopus, and ScienceDirect databases were electronically and manually searched up to December 2017, and randomized controlled, clinical controlled trials, cohort studies and retrospective studies where soft tissue changes were measured before and after nonsurgical RME were identified. Study appraisal and synthesis were performed by two reviewers who completed the study selection and quality assessment procedures independently and in duplicate. Data from the involved studies were pooled using Revman 5.3.

Results

A total of 1762 articles were identified after the removal of duplicates. After selection and quality assessment, 15 studies met the inclusion criteria for the systematic review, and 13 articles were ultimately included in the meta-analysis. The quality of the involved studies was relatively moderate. Pre-expansion, postexpansion, and postretention data were pooled. The nasal width, alar base width, and distances from the lower lips to the E line showed significant changes after expansion. Moreover, after retention, the nasal width, mouth width, upper philtrum width, and distance from the lower lip to the E line showed significant increases relative to the baseline values. Limitations of the present study included the moderate quality of the included studies and the fact that the results were based on short-term observations of patients in the growth phase.

Conclusion

Our findings suggest that RME results in a significantly increased nasal width, mouth width, upper philtrum width, and distance from the lower lip to the E line after the retention phase. However, the clinical importance of these findings is questionable.

Electronic supplementary material

The online version of this article (10.1186/s13005-018-0162-8) contains supplementary material, which is available to authorized users.

Plaque index and gingival index during rapid maxillary expansion of patients with unilateral cleft lip and palate

OBJECTIVE

To assess, during rapid maxillary expansion, the plaque index (PI) and the gingival index (GI) of patients with unilateral cleft lip and palate(UCLP) using Hyrax (HX) or inverted mini-Hyrax (IMHX) rapid maxillary expanders (RME) considering patients' sex and age.

METHODS

PI (Quigley Index modified by Turesky et al) and GI (Löe and Silness) of 28 UCLP (11 females; 17 males: aged 8 to 15 years) submitted to daily RME activation were assessed before (T0) and 7 (T1), 28 (T2) and 90 (T3) days after activation. Log-linear models and Bonferroni correction were performed to analyze possible differences in PI and GI between RME, sexes or age groups over time.

RESULTS

Intra-group comparison revealed significant increases in PI of patients using HX (T0 < T2), IMHX (T0 < T3; T1< T3), males (T0 < T1; T0 < T2; T0 < T3) or aged 12-15 years (T0 < T1; T0 < T2; T0 < T3), and in GI of patients using IMHX (T0 < T3; T1 < T3), females (T1 < T3; T2 < T3) or aged 12-15 years (T0 < T3; T2 < T3). One inter-group difference in GI according to patients' age (8-11 < 12-15; T1) was observed.

CONCLUSIONS

Since a single difference between groups was encountered, the results of this study indicated that PI and GI during maxillary expansion were similar between HX and IMHX, sexes and the analyzed age groups. Therefore, orthodontists can use these RME in UCLP patients according to the patient's necessity or their preferences.

Longitudinal effects of rapid maxillary expansion on masticatory muscles activity

BACKGROUND

To investigate the modifications induced by rapid maxillary expansion (RME) on the electromyographic (EMG) activities of the anterior temporal and superficial masseter muscles, in patients without pre-treatment EMG alterations.

MATERIAL AND METHODS

Twenty-one patients with unilateral posterior cross-bite selected from the orthodontic department of the University of L'Aquila (Italy), were enrolled. There was no control group in this study since each subject acted as a control of her/himself. Two surface EMG recordings were taken: T0 (before RME) and at T1 (3 month after the end of expansion). To verify the neuromuscular equilibrium, the EMG activities of both right and left masseter and anterior temporal muscles were recorded during a test of maximum clench. EMG indexes were compared by paired Student's t-test.

RESULTS

In both occasions, all indices showed a good symmetry between the right and left side masticatory muscles. No statistically significant differences were found between the two recordings.

CONCLUSIONS

In children without pre-treatment EMG alterations, no variations in standardized muscular activity after RME were found. The treatment did not alter the equilibrium of the masseter and temporal muscles. Key words:Rapid maxillary expansion, electromyography, masticatory muscles.

Miniscrew-assisted rapid palatal expansion for managing arch perimeter in an adult patient

INTRODUCTION:

Etiology of dental crowding may be related to arch constriction in diverse dimensions, and an appropriate manipulation of arch perimeter by intervening in basal bone discrepancies cases, may be a key for crowding relief, especially when incisors movement is limited due to underlying pathology, periodontal issues or restrictions related to soft tissue profile.

OBJECTIVES:

This case report illustrates a 24-year old woman, with maxillary transverse deficiency, upper and lower arches crowding, Class II, division 1, subdivision right relationship, previous upper incisors traumatic episode and straight profile. A non-surgical and non-extraction treatment approach was feasible due to the miniscrew-assisted rapid palatal expansion technique (MARPE).

METHODS:

The MARPE appliance consisted of a conventional Hyrax expander supported by four orthodontic miniscrews. A slow expansion protocol was adopted, with an overall of 40 days of activation and a 3-month retention period. Intrusive traction miniscrew-anchored mechanics were used for correcting the Class II subdivision relationship, managing lower arch perimeter and midline deviation before including the upper central incisors.

RESULTS:

Post-treatment records show an intermolar width increase of 5 mm, bilateral Class I molar and canine relationships, upper and lower crowding resolution, coincident dental midlines and proper intercuspation.

CONCLUSIONS:

The MARPE is an effective treatment approach for managing arch-perimeter deficiencies related to maxillary transverse discrepancies in adult patients.

Mandibular dental arch short and long-term spontaneous dentoalveolar changes after slow or rapid maxillary expansion: a systematic review

OBJECTIVE:

The aim of this systematic review was to analyze the short and long-term spontaneous dentoalveolar changes of the mandibular dental arch after slow (SME) or rapid (RME) maxillary expansion in the mixed and early permanent dentitions.

METHODS:

An electronic search was performed in the following databases: PubMed/Medline, Cochrane Library, Scopus, Embase and Web of Science. Eligibility criteria for article selection included randomized controlled trials and prospective studies written in English, with no restriction of year of publication, involving patients who underwent SME or RME during the mixed or early permanent dentitions. A double-blind search of articles was performed by two reviewers. Initially, the title and the abstract of the studies were read, and their references were also hand-searched for possible missing studies. A methodological quality scoring scale was used to analyze the selected articles.

RESULTS:

The search retrieved 373 articles, but only 6 were selected for review after application of the eligibility and exclusion criteria. Non-clinically significant spontaneous dentoalveolar changes of approximately 1mm were found in the mandibular dental arch in the short and long-term, after slow or rapid maxillary expansions. Furthermore, no significant differences were found between treated and control groups.

CONCLUSIONS:

There is enough evidence to conclude that negligible short and long-term spontaneous dentoalveolar changes tend to occur in the mandibular dental arch after SME or RME in the mixed and early permanent dentitions. More randomized studies with appropriate control group are required to better evaluate this issue.

Assessment of the dental and skeletal effects of fan-type rapid maxillary expansion screw and Hyrax screw on craniofacial structures

Aims and Objectives:

The purpose of the study was to assess the skeletal and dental effects of fan-type rapid maxillary expansion (RME) appliance and Hyrax RME appliance on the craniofacial structures.

Materials and Methods:

The sample of the study included 12 patients with constricted maxillary arches. Acrylic bonded type of attachment was used for both groups. Changes in sagittal, vertical, and transverse relationship were assessed with lateral and frontal cephalograms, respectively. Intercanine and intermolar widths were measured with stone models. Pre- and immediate post-treatment records were statistically analyzed with Wilcoxon signed-rank test. The differences between the groups were evaluated using Mann–Whitney U-test. Since the data pertaining to intercanine width and intermolar width were normally distributed, parametric test of significance (unpaired t-test) was used to compare them.

Results:

Results showed that Hyrax presented with significantly greater increments for both nasal cavity width and maxillary width when compared to fan-type RME. Both groups had retroclination of incisors. The increase in the intercanine width was almost similar in both groups.

Conclusion:

Fan-type RME caused only minimal expansion of the intermolar width when compared to the Hyrax. The ratio between the intercanine and intermolar width expansion was nearly 4:1 in the fan-type RME and 0.75:1 in Hyrax.

Assessment of vertical changes during maxillary expansion using quad helix or bonded rapid maxillary expander

OBJECTIVE

To determine if there is a significantly different effect on vertical changes during phase I palatal expansion treatment using a quad helix and a bonded rapid maxillary expander in growing skeletal Class I and Class II patients.

MATERIALS AND METHODS

This retrospective study looked at 2 treatment groups, a quad helix group and a bonded rapid maxillary expander group, before treatment (T1) and at the completion of phase I treatment (T2). Each treatment group was compared to an untreated predicted growth model. Lateral cephalograms at T1 and T2 were traced and analyzed for changes in vertical dimension.

RESULTS

No differences were found between the treatment groups at T1, but significant differences at T2 were found for convexity, lower facial height, total facial height, facial axis, and Frankfort Mandibular Plane Angle (FMA) variables. A comparison of treatment groups at T2 to their respective untreated predicted growth models found a significant difference for the lower facial height variable in the quad helix group and for the upper first molar to palatal plane (U6-PP) variable in the bonded expander group.

CONCLUSION

Overall, both the quad helix expander and the bonded rapid maxillary expander showed minimal vertical changes during palatal expansion treatment. The differences at T2 suggested that the quad helix expander had more control over skeletal vertical measurements. When comparing treatment results to untreated predicted growth values, the quad helix expander appeared to better maintain lower facial height and the bonded rapid maxillary expander appeared to better maintain the maxillary first molar vertical height.

Applications of Cone Beam Computed Tomography in Orthodontics: A Review

Cone Beam Computed Tomography (CBCT) is being extensively used in orthodontics for diagnostic and treatment planning, especially in complex clinical conditions. The objective of this study was to review the English language literature for current applications and trends of CBCT in orthodontic diagnosis and treatment. Several electronic databases were searched with the primary words: "orthodontics and radiography" and "cone beam computed tomography" or "CBCT." Abstracts that appeared to fulfill our inclusion criteria were selected, and the complete articles were obtained. Twenty-eight abstracts initially met our search criteria, and 12 were selected for the review. Ten articles were later added to the list after hand searching the references. It was concluded that there is a need for prospective randomized clinical trials to evaluate the risk/benefit ratio of CBCT, such as higher cost, greater risk for radiation dose (compared to digital panoramic and cephalograms) versus superior diagnosis and treatment outcomes.

The effects of rapid maxillary expansion on voice function

OBJECTIVE

To evaluate the effects of rapid maxillary expansion (RME) on vocal function in patients with bilateral maxillary crossbite.

MATERIALS AND METHODS

We designed our research as a prospective, controlled, clinical study. The treatment group and the control group each had 20 subjects for a total of 40 subjects. Acoustic voice samples were recorded from all patients at T₁ and T₂ by the Multi-Dimensional Voice Program (MDVP Model 5105) for acoustic analysis in Computerized Speech Lab (CSL).

RESULTS

No statistically significant differences were found between the treatment and control groups in the means of any parameters.

CONCLUSIONS

RME does not change vocal quality or resonance, so it can be safely used with patients.

Effects of different rapid maxillary expansion appliances on facial soft tissues using three-dimensional imaging

OBJECTIVE

To determine three-dimensional (3D) effects of three different rapid maxillary expansion (RME) appliances on facial soft tissues.

MATERIALS AND METHODS

Forty-two children (18 boys, 24 girls) who required RME treatment were included in this study. Patients were randomly divided into three equal groups: banded RME, acrylic splint RME, and modified acrylic splint RME. For each patient, 3D images were obtained before treatment (T1) and at the end of the 3-month retention (T2) with the 3dMD system.

RESULTS

When three RME appliances were compared in terms of the effects on the facial soft tissues, there were no significant differences among them. The mouth and nasal width showed a significant increase in all groups. Although the effect of the acrylic splint RME appliances on total face height was less than that of the banded RME, there was no significant difference between the appliances. The effect of the modified acrylic splint appliance on the upper lip was significant according to the volumetric measurements (P < .01).

CONCLUSIONS

There were no significant differences among three RME appliances on the facial soft tissues. The modified acrylic splint RME produced a more protrusive effect on the upper lip.

A comparison of three-dimensional stress distribution and displacement of naso-maxillary complex on application of forces using quad-helix and nickel titanium palatal expander 2 (NPE2): a FEM study

Background

Our objectives are to analyse and to compare the stress distribution and displacement of the craniofacial structures, following the application of forces from quad-helix and Nickel Titanium Palatal Expander-2 (NPE2) using finite element analysis.

Methods

Three-dimensional finite element models of young dried human skull, quad-helix appliance and NPE2 were constructed, and the initial activation of the expanders was stimulated to carry out the analysis and to evaluate the Von Misses stresses and displacement.

Results

Both the models demonstrated the highest stresses at the mid-palatal suture, with maximum posterior dislocation. The second highest stress was recorded at the fronto-zygomatic suture. The pattern of stress distribution was almost similar in both the groups, but NPE2 revealed lower magnitude stresses than quad-helix. The only exception being quad-helix model showed high stress levels around pterygo-maxillary suture whereas minimal stress around pterygo-maxillary suture was noticed after NPE2 activation. The cusp of the erupting canine and the erupting mesiobuccal cusp of the second molar showed outward, backward and downward displacement signifying increase in their eruption pattern following maxillary expansion.

Conclusions

Maxillary expansion using quad-helix and NPE2 can be used in posterior crossbite correction in cases where maximum skeletal changes are desirable at a younger age; it is furthermore effective in treating young patients with impacted or displaced teeth. Quad-helix and NPE2 produced acceptable forces for orthopaedic treatment even after being orthodontic appliances; their clinical application should be correctly planned as the effects of these appliances are largely age dependent.

Effects of rapid maxillary expansion on facial soft tissues : Deviation analysis on three-dimensional images

OBJECTIVE

Changes in soft tissue in various morphological regions of the face immediately after rapid maxillary expansion (RME) were examined using three-dimensional (3D) deviation analyses.

PATIENTS AND METHODS

A total of 50 patients were included in the study; 25 patients (11 female and 14 male) presented with a unilateral or bilateral posterior crossbite malocclusion requiring RME. In addition, 25 patients (13 female and 12 male) were included as a control group. The mean ages of the study group and control group were 9.8 years (range 8.1-12.6 years) and 9.6 years (range 8.3-12.2 years), respectively. The 3D stereophotogrammetric images acquired immediately before the appliance was cemented and after expansion had been completed in the treatment group were compared using Rapidform software. The 3D deviation analyses were made for the complete face and in the upper and lower face, upper and lower lips and nose regions. The amount of negative and positive deviations and the mean deviations were examined on the facial meshes for the 95th percentiles.

RESULTS

Immediately after RME, the mean absolute deviation over the complete face was 0.54 ± 0.16 mm. The mean change for the upper face was 0.42 ± 0.17 mm (mean positive deviation: 0.37 ± 0.17 mm; mean negative deviation: -0.48 ± 0.18 mm). The mean absolute deviation was 0.62 ± 0.28 mm in the upper lip and 0.60 ± 0.34 mm in the lower lip. In the nose area, the absolute deviation was 0.41 ± 0.21 mm (mean positive deviation: 0.39 ± 0.16 mm; mean negative deviation: -0.43 ± 0.26 mm).

CONCLUSIONS

Changes in facial soft tissues in the upper face, lower face, nasal soft tissues, and lower and upper lip regions were observed after RME.

Evaluation of Changes in Lip Closing Force After Surgically Assisted Rapid Maxillary Expansion

OBJECTIVE

Morphological changes in patients subjected to surgical treatment to correct occlusal discrepancies may lead to various functional changes. The aim of the present study was to evaluate changes in lip closing force after surgically assisted rapid maxillary expansion in skeletally mature patients.

METHODS

The study involved 7 female and 7 male patients treated with surgically assisted rapid maxillary expansion. Maximum and minimum lip pressures of patients were measured with Lip De CumLDC-110R. The intercanine distance and incisors angulations were measured preoperatively (T0), at the end of the expansion (T1), at the end of the third month of retention (T2), and at the end of the sixth month of retention (T3).

RESULTS

The greatest values of maximum and the minimum lip closing force were observed at the end of the expansion period significantly. The intercanine distance and inclinations of incisors measured at the third and sixth months showed a significant decrease.

CONCLUSIONS

The present study demonstrated that, following surgically assisted rapid palatal expansion, both the maximum and the minimum lip closing force increases had a tendency to revert to their initial values 6 months after surgery.

Comparison of transverse changes during maxillary expansion with 4-point bone-borne and tooth-borne maxillary expanders

INTRODUCTION

The purposes of this study were to evaluate and compare the dentoskeletal changes concurrent with 4-point bone-borne and tooth-borne rapid maxillary expanders in growing children.

METHODS

The study was conducted with 20 growing girls (ages, 12 ± 0.6 years) with posterior crossbite. They were divided into 2 equal groups; patients in one group were treated with a tooth-borne maxillary hyrax expander (TBME), and those in the other group received a bone-borne maxillary hyrax expander (BBME) anchored directly to the palatal bone. Changes were assessed using cone-beam computed tomography. Images were taken before and immediately after expansion.

RESULTS

Superimpositions of the 3-dimensional palatal images showed significant increases in skeletal widths at the canine, first premolar, and first molar areas in both groups. The TBME group had greater nasal width expansion. Regarding the transverse dentolinear measurements, significant increases were seen in both groups, whereas the TBME group showed a greater increase than the BBME group. Significant increases in the dentoangular measurements were seen in the TBME group only and were significantly greater than in the BBME group at the first premolars.

CONCLUSIONS

There were significant increases in facial and maxillary widths for the BBME group and in nasal width for the TBME group. Both expanders produced basal bone expansion at the level of the hard palate. The TBMEs produced more dental expansion, buccal rolling, and a greater increase in nasal width than did the BBMEs.

Occlusal traits in children with neurofibromatosis type 1

OBJECTIVES

Literature is poor of data about the occlusion in children affected by neurofibromatosis type 1 (NF1). This case-control study investigated the occlusal traits in a group of children with NF1.

SETTING AND SAMPLE POPULATION

A hundred and fifteen children with NF1 were enrolled; non-NF1 controls were sequentially selected among subjects referred to the Pediatric Dentistry Department.

MATERIAL AND METHODS

All patients underwent a clinical dental examination and a panoramic radiography. The following orthodontic variables were considered: molar relationship, overjet, overbite, cross-bite, scissor bite, and crowding/spacing.

RESULTS

Class III molar relationship resulted significantly (p = 0.01) more common in children with NF1 than in the control group as well as the unilateral posterior cross-bite (p = 0.0017). Forty-three children with NF1 (37.3%) showed radiographic abnormalities; in one case, a plexiform neurofibroma was detected.

CONCLUSIONS

An early orthodontic evaluation might be planned in the management of children with NF1 to prevent or decrease the need for extensive orthodontic interventions.

Evaluations of sagittal and vertical changes induced by surgically assisted rapid palatal expansion

INTRODUCTION

Class II, anterior open bite and/or a steep mandibular plane angle are frequently considered a contraindication to the use of surgically assisted rapid palatal expansion (SARPE). Nevertheless, few studies have investigated the maxillary and mandibular effects after SARPE on the sagittal and vertical planes, with dissimilar results and small samples of patients.The aim of the current study was to evaluate the sagittal and vertical effects after SARPE.

METHODS

Twenty-one consecutive adult patients (7 males, 14 females; mean age, 25.6 ± 6.3 years) who required SARPE were included in this study. All patients were subjected to subtotal LeFort I osteotomy with pterygomaxillary disjunction. Lateral cephalometric radiographs were taken during the preoperative assessment (T0) and 6 months after the end of the expansion (T1). Cephalometric measurements were realized at T0 and T1 for all the patients. Independent-sample t test and analysis of variance were used.

RESULTS

Statistically significant changes were observed only in upper incisor^NA (P = 0.04). No skeletal sagittal or vertical variation was found after SARPE.

CONCLUSIONS

Class II, anterior open bite and/or a steep mandibular plane angle cannot be considered an outright contraindication to its use. Upper incisor palatal inclination could result after SARPE.

Comparison between rapid and mixed maxillary expansion through an assessment of arch changes on dental casts

Background

Aim of this retrospective observational study was to compare upper and lower dental changes in patients treated with Rapid Maxillary Expansion (RME) and Mixed Maxillary Expansion (MME), assessed by dental cast analysis.

Methods

Treatment groups consisted of 42 patients: the RME group (n = 21) consisted of 13 female and 8 male subjects with the mean age of 8.8 years ± 1.37 at T0 and 9.6 years ± 1.45 at T1; the MME group (n = 21) consisted of 12 female and 9 male patients with a mean age of 8.9 years ± 2.34 at T0 and 10.5 years ± 2.08 at T1. The upper and lower arch analysis was performed on four dental bilateral landmarks, on upper and lower casts; also upper and lower arch depths were measured. The groups were compared using independent sample t-test to estimate dental changes in upper and lower arches.

Results

Before expansion treatment (T0), the groups were similar for all examined variables (p>0.05). In both RME and MME group, significant increments in all the variables for maxillary and mandibular arch widths were observed after treatment. No significant differences in maxillary and mandibular arch depths were observed at the end of treatment in both groups. An evaluation of the changes after RME and MME (T1) showed statistically significant differences in mandibular arch depth (p<0.001) and maxillary intercanine widths (p<0.05). Differences in maxillary arch depth and arch width measurements were not significant.

Conclusions

RME and MME can be considered two effective treatment options to improve transverse arch dimensions and gain space in the dental arches. A greater lower arch expansion was observed in the MME group, which might be attributed to the “lip bumper effects” observed in the MME protocol.