The biomechanics of rapid maxillary sutural expansion

Effect of treatment of transverse maxillary deficiency using rapid palatal expansion on oral health-related quality of life in children: complementary results for a controlled clinical trial

OBJECTIVE

To evaluate the effect of rapid palatal expansion (RPE) using Haas-type expanders on children's oral health-related quality of life (OHRQOL) and compare said effect with that previously reported for the use of Hyrax-type expanders.

MATERIALS AND METHODS

Forty participants aged 8-10 years with transverse maxillary deficiency were treated using Haas appliances. OHRQOL was measured using the CPQ8 - 10 before RPE, during RPE (T1), at the end of RPE (T2), and 1 month after appliance removal (T3). Generalized mixed models were fitted to assess the effect of the Haas-type expander compared to previously collected data (a nontreated and a Hyrax-type expander-treated group).

RESULTS

RPE with Haas-type appliances had a negative impact on overall OHRQOL at T1 and T2 (P = 0.001), and a positive impact at T3 (P = 0.001). The Haas-type expander had a significantly greater negative impact on OHRQOL than the Hyrax-type appliance during RPE. At T1, overall scores using the Haas-type expander were 1.08 times the scores using the Hyrax-type expander (i.e., 8% increase; 95% CI, 1.01-1.17; P = 0.033). Patients using the Haas appliance had 1.24 times the scores of those using Hyrax-type devices for the oral symptoms domain at T1 (i.e., 24% increase; 95% CI, 1.06-1.46; P = 0.009).

CONCLUSIONS

Correction of the transverse maxillary deficiency by RPE using the Haas appliance in children 8-10 years improves OHRQOL. The Haas- and Hyrax-type devices temporarily worsen OHRQOL during treatment, however, the negative impact is less with the Hyrax-type expander than with the Haas-type expander, because it causes fewer negative oral symptoms.

CLINICAL RELEVANCE

From a patient-centered perspective, the use of the Hyrax over the Haas appliance may be suggested as it causes less negative oral symptoms during use.

Numerical study of the impact of osteotomies and distractor location in surgically assisted rapid palatal expansion for transverse maxillary deficiency

INTRODUCTION

This paper employs finite element analysis to assess the biomechanical behavior of surgically assisted rapid palatal expansion (SARPE) with a bone-borne transpalatal distractor (TPD) by varying surgical parameters.

MATERIAL AND METHODS

Nine models were constructed to scrutinize the effects of pterygomaxillary disjunction (PMD), lateral osteotomy positioning, and TPD placement on displacement profiles and Von Mises stresses. These models encompassed variations such as no, unilateral or bilateral PMD, asymmetrical lateral osteotomy, and five TPD locations.

RESULTS

Performing a PMD reduces posterior resistance to transverse expansion, resulting in 10-20 % stress reduction around the maxillofacial complex. No significant changes in horizontal tipping were observed post-PMD. The asymmetric lateral osteotomy model exhibited larger displacements on the side with a more superiorly positioned osteotomy. Reduced stresses were observed at the maxillary body and medial pterygoid plate (superiorly), while increased stresses were observed at the medial (inferiorly) and lateral pterygoid plates. More posterior TPD placement facilitated more parallel expansion thus less horizontal tipping, albeit with increased vertical tipping.

DISCUSSION

SARPE procedures (distractor and osteotomy positions) can be tailored based on desired outcomes. PMD reduces stress within the maxillofacial complex but doesn't significantly affect tipping. Higher lateral osteotomies lead to increased displacements, more posterior distractors to more parallel expansion.

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.

Comparison of 3D-printed and laboratory-fabricated Hyrax on stress distribution and displacement of the maxillary complex: a 3D finite element study

OBJECTIVE

To analyze and compare the effects of a traditional laboratory-fabricated Hyrax expander (T-Hyrax) and two different 3D-printed Hyrax expander models relative to tension points, force distribution, and areas of concentration in the craniofacial complex during maxillary expansion using finite element analysis.

MATERIALS AND METHODS

Three maxillary expanders with similar designs, but various alloys were modeled: a T-Hyrax, a fully printed Hyrax (F-Hyrax), and a hybrid printed Hyrax (H-Hyrax). The stress distributions and magnitude of displacements were assessed with a 5 mm expansion in a symmetrical finite element model. The areas of interest included the teeth, alveolar processes, midpalatal suture, nasal complex, circummaxillary sutures (CS), and the expanders themselves.

RESULTS

The highest stress value (29.2 MPa) was found at the midpalatal suture of the F-Hyrax, while the lowest stress (0.90 MPa) was found at the temporozygomatic suture in the T-Hyrax. On average, the F-Hyrax increased stress at the CS by 24.76% compared with the T-Hyrax and H-Hyrax. The largest displacements were found at the upper incisor (U1) and anterior nasal spine (ANS). The findings indicated an average increase of 12.80% displacement at the CS using the F-Hyrax compared to the T-Hyrax.

CONCLUSION

The F-Hyrax exerts more stress and displacement on the maxilla than both the T-Hyrax and H-Hyrax, where the weak link appears to be the solder joint.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Dental arch changes comparison between Expander with Differential Opening, Hyrax-type and Haas-type expanders: A prospective clinical study

OBJECTIVE

Compare changes in arch form after RME achieved by Expander with Differential Opening (EDO), Hyrax-type and Haas-type expanders.

MATERIALS AND METHODS

Dental models were obtained from 61 patients aged 7-11 years before expansion (T1) and 6 months after the active phase when the appliances were removed (T2). The groups were formed according to the expander used: EDO (n = 18, mean age: 9.46 ± 0.82 years), Hyrax-type (n = 22, mean age: 9.62 ± 1.57 years) and Haas-type (n = 21, mean age: 9.29 ± 1.05 years). The expander`s activation protocol consisted of 7 mm, except for EDO`s anterior screw, which was 9 mm. The measurements of upper and lower intercanine distance, inter-first permanent molar, arch perimeter and length, maxillary canine and first-permanent molar inclination, and palatal depth were performed using the OrthoAnalyzer 3D software. Intergroup comparisons of T1 and between changes (T2-T1) were performed using ANOVA followed by Tukey.

RESULTS

In the upper intercanine distance EDO provided a greater increase than Haas-type. In the distance between upper fist permanent molars EDO showed higher values than Haas-type and Hyrax-type. In the lower intercanine distance and maxillary arch length, Haas-type promoted higher increase than EDO.

CONCLUSIONS

The EDO promoted greater transverse changes in anterior region than Haas-type and greater transverse changes in posterior region of the maxilla than both conventional expanders. The appliance used for RME influences dental arch changes after treatment; therefore, it is recommended to individualize the choice of expander depending on the clinical necessity of each case.

3D occlusal changes of upper first molars after rapid maxillary expansion on permanent versus deciduous teeth: a retrospective multicenter CBCT study

BACKGROUND

The purpose of this study was to compare the three-dimensional dental changes for the maxillary first molars and the overall skeletal effects achieved after expansion between the rapid maxillary expansion (RME) appliance attached to two different anchor units, the maxillary deciduous molars and the maxillary permanent first molars.

METHODS

Patients were retrospectively selected according to the anchorage unit used for RME: deciduous upper second molars (RME-E group; 10 M, 10 F; mean age 8.4 ± 1.1 years) and first upper permanent molars (RME-6 group; 10 M, 10 F; mean age 12.6 ± 1.8 years). CBCT scans were obtained before treatment start (T1) and after retention and removal of the expander (T2). Images were analyzed using a new three-dimensional intra-hemi-maxillary reference system. 3D landmarks were marked to calculate all changes on maxillary first permanent molars; mesio-distal and buccal-lingual inclination and rotation, as well as intermolar and interforaminal distances were calculated. The Wilcoxon test was used to compare within-group changes, whereas the Mann-Whitney test was used to compare between-group differences, with the significance level set at 0.05.

RESULTS

In the RME-E group, significant distorotation and lingual inclination of the first permanent molars at T2 were observed (p < 0.01); in the RME-6 group, only the buccolingual inclination of the crossbite side after RME was resulted statistically significant (p < 0.01). In both groups, intermolar and interforaminal values increased significantly (p < 0.01). Intergroup analysis showed a significantly higher distorotation and reduced buccal inclination of maxillary first permanent molars in the RME-E group after RME (p < 0.01).

CONCLUSIONS

RME is effective in treating maxillary transverse hypoplasia; RME anchored too deciduous teeth spontaneously reduces buccal inclination and increases distorotation of maxillary first permanent molars, whereas anchorage to permanent molars is associated with increased buccal inclination, albeit with little clinical significance.

Age-dependent effects on palate volume and morphology during orthodontic RME treatment

OBJECTIVES

Rapid maxillary expansion (RME) shows different age-dependent effects. It has been shown that RME leads to a parallel expansion prior to the age of 10, while later and especially from the age of 12, a V-shaped expansion happens (transverse, anterior > posterior; horizontal, inferior > superior). However, it is not clear to what extent these effects influence palatal volume and morphology and eventually maxillary functional space. The aim of the present study was to examine possible age-related effects of treatment with a dental anchored RME appliance upon volume and width/height ratio of the anterior and posterior palate.

MATERIALS AND METHODS

Sixty children and adolescents with documented treatment histories after RME were divided into three equal groups according to age at treatment begin (PG 1, < 10 years, n=20; PG 2, 10 ≤ 12 years, n=20; PG 3, > 12 years, n=20). Maxillary dental casts before and after therapy were digitised. Changes in palatal volume were determined using 3D analyses.

RESULTS

In all patients, the palatal volume increases significantly after RME. Older patients experienced smaller increases in total and posterior volume in absolute and percentage terms. The anterior palate volume increases are almost equal in all patients. Since palatal width increases more markedly than palatal height, the width/height ratio always increases. Except for the posterior region in PG 3, its increase is significant in all groups, both anteriorly and posteriorly. After successful RME, the palatal morphology appears normal anteriorly in PG 1, PG 2 and PG 3 and rather steep posteriorly in PG 3.

CONCLUSIONS

RME treatment with identical force application causes different, age-dependent effects upon palate volume and morphology. Width changes have a greater influence on palate volume than height changes.

CLINICAL RELEVANCE

It is preferable to use an RME prior to the age of 10 if homogeneous changes of the anterior and posterior palate regarding maxillary symmetry and functional space are desired.

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.

Rapid Maxillary Expansion Treatment in Patients with Cleft Lip and Palate: A Survey on Clinical Experience in the European Cleft Centers

Cleft lip and palate patients require complex interdisciplinary treatment, including maxillary expansion and secondary alveolar bone grafting. However, the evidence on these treatment procedures and outcomes is lacking. Therefore, this study aimed to survey the subjective observations of European maxillofacial surgeons and orthodontists on the maxillary expansion and bone grafting treatment protocols and the associated complications. An online questionnaire was sent to 131 centers. The questions assessed the participants' demographic data, maxillary expansion and alveolar bone grafting protocols, and the associated complications. Descriptive statistics and a t-test were used to analyze the data. The response rate was 40.5%. The average age for maxillary expansion was 9-10 years. The secondary alveolar bone grafting was planned 5-10 months after the expansion. The most common complications were asymmetric expansion, relapse, and fistula formation. The protocols and materials used vary widely among centers. Anatomical alterations and developmental processes, like tooth eruption adjacent to the cleft, should be seriously considered for treatment planning. This survey showed that there is still a lack of consensus on these treatment procedures. Further clinical trials should focus on long-term outcome evaluation to identify treatment components for optimal alveolar bone substitution and transversal maxillary expansion treatment in patients with clefts.

Immediate skeletal effects of rapid maxillary expansion at midpalatal suture opening with Differential, Hyrax and Haas expanders

OBJECTIVE

The aim of this study was to test the null hypothesis that there is no difference at the midpalatal suture opening after rapid maxillary expansion (RME) using Expander with Differential Opening (EDO), Hyrax-type and Haas-type expanders.

METHODS

Occlusal radiographs of 52 patients (19 males and 33 females; average age= 9.46?1.20 years) treated with RME were divided into three groups, according to the expander used: EDO (n=17), Hyrax-type (n=21) and Haas-type (n=14). The evaluated variables were: A) Distance between the maxillary central incisors at the incisal edge; B) Distance between the alveolar ridges at the midpalatal suture; C) Suture opening at 10-mm distance from the crest to posterior, at the midpalatal suture; D) Suture opening at 20-mm distance from the crest to posterior, at the midpalatal suture; and E) Suture opening at 30-mm distance from the crest to posterior, at the midpalatal suture. To assess the normality of variables, the Shapiro-Wilk test was performed. For intergroup comparison, ANOVA with a significance level of 5% was used.

RESULTS

At the region A, Hyrax-type (4.66 mm) and EDO (4.87 mm) groups presented larger openings than the Haas-type group (3.43 mm). In regions B and C, EDO showed a statistically significant greater opening than the Haas-type group. In region D, a smaller opening of the midpalatal suture was observed in the Haas-type group, compared to the Hyrax-type and EDO groups.

CONCLUSIONS

EDO and Hyrax-type produced greater immediate skeletal effects, compared with Haas-type, but these differences were about 1 mm and might not be clinically significant.

Age-dependent interactions of maxillary sutures during RME and their effects on palatal morphology : CBCT and dental cast analysis

PURPOSE

The effects of rapid maxillary expansion (RME) on the transverse palatine and midfacial sutures have been extensively scrutinized. Unlike the dentition stage, age-dependency was not yet regarded when investigating morphological changes of the tooth-bearing palate. Therefore, the first aim of the present study was to analyse age-dependent sutural and morphological changes of the palate in selected patients by cone-beam computed tomography (CBCT) and dental cast analysis. Secondly, age-dependent effects of RME on width, height, and depth of the palate in the region of the maxillary palatine processes were investigated by a comprehensive dental cast study, so that the combination of results could be used to provide a biomechanical explanation of the occurring changes.

METHODS

CBCT datasets of 9 patients (between 7.3 and 13.8 years) were measured around the median palatal suture and compared with the results of an individualised dental cast analysis. In addition, possible effects on other maxillary sutures were investigated. In the dental cast study, changes after RME in the tooth-bearing palate were analysed three-dimensionally in 60 children and adolescents. It was possible to divide those into three equally sized, age-dependant groups (PG1: < 10 years, n = 20; PG2: ≥ 10 < 12 years, n = 20; PG3: ≥ 12 years, n = 20).

RESULTS

The CBCT analysis reveals age-related differences in sutural responses. The opening width of the median palatine suture decreases cranially (frontal) and dorsally (horizontal). The opening mode thus changes from parallel to triangular in both planes. The transverse palatine suture completely opens in younger patients only (PG1 and PG2). The width increases are always significant in all patients. While in PG1 the width increase is greater posteriorly than anteriorly, this is always reversed in PG2 and PG3. The palatal height always increases significantly anteriorly, but posteriorly only in the youngest patients (PG 1) median and paramedian. In PG 2 and PG 3, the posterior height change is very small. That is the reason why the anteroposterior comparison reveals a much more pronounced height increase anteriorly than posteriorly.

CONCLUSION

The comparison of selected CBCT data with a dental cast analysis allows the conclusion that the maxillary expansion after RME in children up to 10 years is rather parallel, whereas it occurs V‑shaped (anterior > posterior transversal, inferior > superior vertical) with increasing age, especially in adolescents from the age of 12. In addition to an age-progressive rigidity of the pterygopalatomaxillary junction, morphological changes of the transverse palatine suture during growth seem to be causal. Thus, age-dependent effects of palatal expansion occur due to a positional change of maxillary centres of rotation and resistance. From dental cast measurements, especially at the skeletal-basal level, conclusions can be drawn about the median palatal suture opening mode.

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

Objective

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

Methods

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

Results

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

Conclusions

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Three-dimensional craniofacial changes with maxillary expansion in young adult patients with different craniofacial morphology

Objectives:

Skeletally mature patients with transverse deficiency are best treated with surgically assisted rapid palatal expansion (RPE) procedure. Recent studies have shown that microimplant-assisted RPE (MARPE) appliances can be effective in achieving skeletal expansion in young adults. This retrospective study aimed to evaluate the skeletal and dental alveolar changes in response to treatment with MARPE appliances in three types of anteroposterior skeletal malocclusions using cone-beam computed tomography (CBCT) scans.

Material and Methods:

Seventy-eight subjects diagnosed with maxillary transverse deficiency and treated with the MARPE appliance (mean age of 22.9 ± 4.2 years) were divided into skeletal Class I, II, and III malocclusions with 26 subjects in each group. Pre- and post-treatment CBCT scans were used for superimposition to examine the skeletal and dentoalveolar changes following maxillary expansion treatment.

Results:

Significant lateral separation of the maxilla was found at the levels of the nasal floor, interzygomatic bones, and the inferior palatine margin of the alveolar process (P < 0.05) in the whole sample. Most of the sagittal and vertical variables change significantly in the whole sample and each studied group separately. Intergroup comparisons revealed no significant differences among the three skeletal classes except for the left frontozygomatic angle, left maxillary inclination angle, and torque in the first and second premolars. In Class III patients, the maxilla moved forward significantly in most of the cases (eight of 26 cases) (0.88°, P < 0.05) and the mandible moved downward and backward improving the anteroposterior skeletal relationship. Significant differences were also found in the vertical measurements (N-Me, MMP, and MP/SN, P < 0.05) in all three types of anteroposterior malocclusions.

Conclusion:

Maxillary expansion with the MARPE appliance in young adult patients induced different skeletal and dentoalveolar changes in the anteroposterior and vertical dimensions in each skeletal malocclusion with no significant difference among the three skeletal classes.

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.

Age-dependent effects of transverse maxillary deficiency treated by microimplant-assisted rapid palatal expansion: A prospective cone-beam computed tomography study

INTRODUCTION

This study investigated the results of maxillary discrepancy treated by microimplant-assisted rapid palatal expansion (MARPE) at different ages.

METHODS

Sixty patients (aged 11.0-34.1 years; 23 male and 37 female) were treated by MARPE. Cone-beam computed tomography scans and dental casts were taken before and after expansion. The data were compared among 4 age groups: early adolescents (aged 11-14 years), late adolescents (aged 15-19 years), young adults (aged 20-24 years), and old adults (aged 25-34.1 years).

RESULTS

The success rates of midpalatal suture separation were 100%, 100%, 88.2%, and 85.7% for early adolescents, late adolescents, young adults, and old adults, respectively. Palatal sutures at the level of the first molar were expanded by 4.02 mm, 3.48 mm, 2.63 mm, and 2.10 mm, corresponding to 66.7%, 58.1%, 42.0%, and 37.9% of the total dental expansion. Significant differences were found in the amounts of palatal suture expansion and the ratio of skeletal dental expansion between patients aged <20 years and patients aged ≥20 years (P <0.05). Skeletal expansion constituted 69.4%, 51.3%, 39.0%, and 29.8% of the total screw expansion. Except for the comparison between young adults and old adults, there were significant differences between groups for the ratio of skeletal screw expansion (P <0.05).

CONCLUSIONS

The midpalatal suture can be expanded by MARPE more easily in patients <20 years of age than in patients ≥20 years of age. The ratio of skeletal screw expansion decreases as age increases.

Posterior crossbite with mandibular asymmetry treated with lingual appliances, maxillary skeletal expanders, and alveolar bone miniscrews

Posterior crossbite and mandibular asymmetry affect esthetics and function. We report treatment of 3 patients with posterior crossbite with mandibular asymmetry but different anteroposterior and vertical characteristics. Treatment methods included maxillary skeletal expander, miniscrews, and lingual appliances. The results show that by using these appliances, ideal transverse, anteroposterior, and vertical control is possible in patients who have concerns about the esthetics of buccal appliances. Lingual appliances can provide satisfying results when combined with a maxillary skeletal expander and miniscrews in complex patients.

Short-term effects of microimplant-assisted rapid palatal expansion on the circummaxillary sutures in skeletally mature patients: A cone-beam computed tomography study

INTRODUCTION

This study aimed to investigate the short-term effects on the circummaxillary sutures induced by microimplant-assisted rapid palatal expansion (MARPE) in skeletally mature patients.

METHODS

Cone-beam computed tomography (CBCT) images of preexpansion (T0) and postexpansion (T1) of 23 patients (mean age, 20.9 ± 3.65 years) treated with MARPE were evaluated. The T0 and T1 CBCT images were reoriented and superimposed on the basis of the anterior cranial base, using OnDemand3D software (Cybermed, Seoul, Korea). Then, width changes of 9 circummaxillary sutures (frontonasal, frontomaxillary, frontozygomatic, nasomaxillary, zygomaticomaxillary, intermaxillary, midpalatal, zygomaticotemporal, and pterygopalatine sutures) were measured on 1 section of each patient's T0 and T1 CBCT images. In addition, correlation coefficients between changes in the midpalatal sutures, the amount of appliance activation, age, and the changes in other circummaxillary sutural widths were also calculated.

RESULTS

Statistically significant (P <0.05) width increases were found in all 9 circummaxillary sutures. The changes in midpalatal suture at the maxillary central incisor level positively correlated with the intermaxillary sutures at the anterior nasal spine level, midpalatal sutures at the posterior nasal spine level, and frontomaxillary sutures (P <0.05). In addition, the changes in the midpalatal sutures at the posterior nasal spine level also positively correlated with the changes in the intermaxillary sutures at the anterior nasal spine level, frontomaxillary sutures, and medial pterygopalatine sutures (P <0.05).

CONCLUSIONS

All 9 circummaxillary sutural widths increased in skeletally mature patients immediately after MARPE. The greatest increases in width were measured in the midpalatal sutures and the intermaxillary sutures, followed by the frontomaxillary sutures.

Three-dimensional zygomatic changes after rapid maxillary expansion in growing patients

PURPOSE

To assess the effects of rapid maxillary expansion (RME) treatment on the zygomatic bone complex (ZBC).

METHODS

In this single-center retrospective study, pre- and posttreatment cone-beam computed tomography (CBCT) images of 38 patients treated with RME were analyzed to investigate changes in the coordinates of the ZBC landmarks. At the start of treatment (T0), the patients' mean age was 11.1 ± 3.8 years (range 8.3-14.9 years). Cohen's d test was used to evaluate statistical differences.

RESULTS

There were statistically significant differences between T0 and T1 (P < 0.01) in the measurement values for the maxillary transverse width (ΔT: 3.18 ± 2.58, d: 1.23), frontozygomatic sutures (ΔT: 1.09 ± 0.56, d: 0.43), lowest point of the zygomaticomaxillary sutures (ΔT: 3.16 ± 1.78, d: 0.78), frontomaxillary angular parameter (right side ΔT: 2.81 ± 1.63, d: 1.73; left side ΔT: 2.52 ± 1.20, d: 2.10), frontozygomatic angular parameter (right side ΔT: 2.81 ± 1.63 d: 1.07; left side ΔT: 2.21 ± 2.79, d: 0.61), anterior intermaxillary distance (ΔT: 2.11 ± 1.42, d: 0.99), interzygomaticotemporal distance (ΔT: 2.00 ± 2.42, d: 0.99), and zygomatic angular parameter (right side ΔT: 2.06 ± 1.29, d: 1.6; left side ΔT: 2.02 ± 1.86, d: 1.09).

CONCLUSIONS

After RME in growing patients, the zygomatic bone showed pyramidal expansion in the coronal plane and parallel palatal expansion in the axial plane. In addition, significant lateral relocation of the zygomatic bone occurred. The zygomatic bone tended to rotate outward in conjunction with the maxilla, with a typical center of rotation close to the superior side of the frontozygomatic suture. These results shed light on the patterns of skeletal expansion in the zygomatic bone associated with RME in growing patients.

CBCT Comparison of Dentoskeletal Effects of Haas-Type and Hyrax-Type Expanders Using Deciduous Teeth as Anchorage: A Randomized Clinical Trial

The aim of this study was to compare the three-dimensional dentoskeletal effects of Haas-type and Hyrax-type expanders using primary teeth as anchorage for rapid palatal expansion (RPE). Thirty-four subjects in mixed dentition were divided according to their expander’s type: Hyrax (n = 16; 6F, 10M; mean age 8 ± 3 years) or Haas (n = 18; 14F, 4M; mean age 8 ± 2 years). Each patient underwent CBCTs before (T0) and after RPE (T1). Dentoskeletal changes were collected. A paired sample t-test and independent t-test were used to compare each variable within the same group and between groups, respectively, with a 5% significance. The Hyrax group showed an increase in all dentoskeletal parameters; skeletal expansion was significantly increased anteriorly (1.76 mm) and posteriorly (1.93 mm). The greatest dental expansion was observed in the anchorage unit (6.47 mm), about twice as much as permanent molars (3.42 mm). The same statistical significance of Haas group measurements was observed; anteriorly skeletal expansion (2.97 mm) was greater than posteriorly (1.93 mm) and dental expansion was greater on anchored teeth (6.80 mm) than non-anchored teeth (4.57 mm). No statistical significance was observed between Hyrax and Hass groups. CBCT analysis showed that, in RPE, the dental expansion was greater than skeletal expansion. No significant or clinical changes were observed between Hyrax and Haas appliances anchored to primary teeth.

Perceived pain during rapid maxillary expansion in children with different expanders

OBJECTIVES

To evaluate and compare the intensity of pain caused by rapid maxillary expansion (RME) with two expanders: Hyrax and Haas type, in growing patients.

MATERIALS AND METHODS

Thirty-nine patients (23 girls and 16 boys) with an average age of 9.3 years (SD = 1.39 years) were randomized into two groups and treated with Hyrax- and Haas-type expanders. In both groups, initial activation of the expander screw was one full turn on the first day followed by 2/4 of a turn two times a day (morning and night) for 7 days. Inclusion criteria were patients presenting with a posterior crossbite or maxillary atresia between 7 and 12 years old. To evaluate the intensity of pain during the active phase of the treatment, a combination of the Numerical Rating Scale and Wong-Baker Faces Pain Scale was used. Mann-Whitney test was used to compare the two treatment groups.

RESULTS

There was significant inverse correlation between days following insertion and pain. During the expansion period, 100% of the children reported some pain. Hyrax expander subjects reported greater pain than those treated with the Haas-type expander only on the first day. The level of pain remained greater in girls throughout treatment.

CONCLUSIONS

Pain was reported regardless of the type of expander and was higher in the Hyrax group only on the first day of activation.

Skeletal width changes after mini-implant-assisted rapid maxillary expansion (MARME) in young adults

OBJECTIVES

To observe skeletal width changes after mini-implant-assisted rapid maxillary expansion (MARME) and determine the possible factors that may affect the postexpansion changes using cone-beam computed tomography (CBCT) in young adults.

MATERIALS AND METHODS

Thirty-one patients (mean age 22.14 ± 4.76 years) who were treated with MARME over 1 year were enrolled. Four mini-implants were inserted in the midpalatal region, and the number of activations ranged from 40 to 60 turns (0.13 per turn). CBCT was performed before MARME (T0), after activation (T1), and after 1 year of retention (T2). The mean period between T1 and T0 was 6 ± 1.9 months and between T2 and T1 was 13 ± 2.18 months. A paired t-test was performed to compare T0, T1, and T2. The correlations between the postexpansion changes and possible contributing factors were analyzed by Pearson correlation analysis.

RESULTS

The widths increased significantly after T1. After T2, the palatal suture width decreased from 2.50 mm to 0.75 mm. From T1 to T2, decreases recorded among skeletal variables varied from 0.13 mm to 0.41 mm. This decrease accounted for 5.75% of the total expansion (2.26 mm) in nasal width (N-N) and 19.75% at the lateral pterygoid plate. A significant correlation was found between postexpansion change and palatal cortical bone thickness and inclination of the palatal plane (ANS-PNS/SN; P < .05).

CONCLUSIONS

Expanded skeletal width was generally stable after MARME. However, some amount of relapse occurred over time. Patients with thicker cortical bone of the palate and/or flatter palatal planes seemed to demonstrate better stability.

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

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

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Influence of different types of rapid maxillary expansion on root resorption: a systematic review

OBJECTIVES

This study aimed to assess the influence of different types of rapid maxillary expansion on root resorption (RR).

METHODS

Literature searches were carried out electronically in five English and two Chinese databases. Randomized controlled trials (RCTs), controlled clinical trials (CCTs), cohort studies, and case-control studies were included. The data were extracted by three authors. The risk of bias in the RCTs and nonrandomized studies were assessed in accordance with corresponding scales.

RESULTS

Among the 400 articles identified, seven were included for the final analysis. Three studies were graded as high value of evidence, while two and another two studies were graded as moderate value and low value, respectively. According to the available evidence, the tooth-borne maxillary expansion caused more obvious RR of anchorage teeth than the bone-borne one. In addition, the Haas-type palatal acrylic pads could not effectively reduce the degree of RR. The difference in the design of the retainer between the tooth-borne maxillary expansion (the use of a band or wire framework to connect the anchorage tooth) did not cause the difference in the incidence and degree of RR.

CONCLUSIONS

Clinical evidence suggested that bone-borne maxillary expansion may decrease the amount of RR, while the amounts of resorption did not significantly differ between Haas and Hyrax and between different retainer types of Hyrax.

Tomographic evaluation of dentoskeletal effects of rapid maxillary expansion using Haas and Hyrax palatal expanders in children: A randomized clinical trial

Background

Rapid maxillary expansion (RME) is a usual procedure for correcting the transversal maxillary deficiency. Among the most used appliances are the Haas type (tooth-tissue-borne) and Hyrax (tooth-borne) whose main difference is the design. This study aimed to evaluate the dentoskeletal effects of RME using two different expanders in children.

Material and Methods

The sample was composed of 42 children of both gender presenting unilateral or bilateral posterior crossbite with mean age 9.49 (SD± 1.35). Patients were randomized into two groups according to the type of expander: Hyrax (n= 21, 9 boys and 12 girls) and Haas (n= 21, 11 boys and 10 girls). Multiplanar coronal and axial slices obtained from cone-beam computed tomography images (i-Cat, Hartsfield, PA, USA) were used at pretreatment (T1) and after 6 months when the expander was removed (T2). Measurements were performed on Dolphin Imaging Systems 11.7 software (Chatsworth, California, USA). The following variables were evaluated: inclinations of the posterior teeth, transverse skeletal widths, length of maxillary dental arch, buccal bone thickness and level of buccal alveolar crest. Statistical analysis performed using chi-squared test to compare the sex ratios between groups and independent t test with the Bonferroni correction for multiple tests.

Results

RME increased all maxillary transverse dimensions, regardless of the type of expanders used. Subjects in the Hyrax group experienced significantly increase in the lingual bone thickness (0.94 mm) compare to Haas group (0.21 mm).

Conclusions

The Hyrax-type expander produced greater increase in the lingual bone thickness than did the Haas-type expander, but this effect might not be clinically significant. Both appliances presented similar transversal gain and tended to produce similar orthopedic and orthodontic effects.

Key words:Cone-beam computed tomography, palatal expansion technique, palate.

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.

A New Methodology for the Digital Planning of Micro-Implant-Supported Maxillary Skeletal Expansion

INTRODUCTION

Miniscrew-assisted rapid palatal expansion (MARPE) appliances utilize the skeletal anchorage to expand the maxilla. One type of MARPE device is the Maxillary Skeletal Expander (MSE), which presents four micro-implants with bicortical engagement of the palatal vault and nasal floor. MSE positioning is traditionally planned using dental stone models and 2D headfilms. This approach presents some critical issues, such as the inability to identify the MSE position relative to skeletal structures, and the potential risk of damaging anatomical structures.

METHODS

A novel methodology has been developed to plan MSE position using the digital model of dental arches and cone-beam computed tomography (CBCT). A virtual model of MSE appliance with the four micro-implants was created. After virtual planning, a positioning guide is virtually designed, 3D printed, and utilized to model and weld the MSE supporting arms to the molar bands. The expansion device is then cemented in the patient oral cavity and micro-implants inserted. A clinical case of a 12.9-year-old female patient presenting a Class III malocclusion with transverse and sagittal maxillary deficiency is reported.

RESULTS

The midpalatal suture was opened with a split of 3.06 mm and 2.8 mm at the anterior and posterior nasal spine, respectively. After facemask therapy, the sagittal skeletal relationship was improved, as shown by the increase in ANB, A-Na perpendicular and Wits cephalometric parameters, and the mandibular plane rotated 1.6° clockwise.

CONCLUSION

The proposed digital methodology represents an advancement in the planning of MSE positioning, compared to the traditional approach. By evaluating the bone morphology of the palate and midface on patient CBCT, the placement of MSE is improved regarding the biomechanics of maxillary expansion and the bone thickness at micro-implants insertion sites. In the present case report, the digital planning was associated with a positive outcome of maxillary expansion and protraction in safety conditions.

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.

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

OBJECTIVE

To evaluate the molar inclination and skeletal and alveolar bone changes when comparing tooth bone-borne (MSE) and tissue bone-borne type maxillary expanders (C-expander) using cone-beam computed tomography (CBCT) in late adolescence.

MATERIALS AND METHODS

A sample of 48 late-adolescent patients were divided into two groups according to the type of expander: MSE group (n = 24, age = 19.2 ± 5.9 years) and C-expander group (n = 24, age = 18.1 ± 4.5 years). CBCT scans were taken before treatment and 3 months after expansion. Transverse skeletal and dental expansion, alveolar inclination, tooth axis, buccal alveolar bone height, thickness, dehiscence, and fenestration were evaluated on the maxillary first molar. Paired t-test, independent t-test, Pearson's chi-square test, and Spearman correlation analysis were performed.

RESULTS

The MSE group produced greater dental expansion (P < .05), whereas skeletal expansion was similar in both groups (P = .859). The C expander group had more alveolar bone inclination change (P < .01), and the MSE group had more buccal tipping of the anchorage teeth (P < .01 or .001). Buccal alveolar bone height loss and thickness changes were greater in the MSE group (P < .01 or <.001). Formation of dehiscences was more frequent in the MSE group (P < .001), whereas for fenestrations, there were no significant differences between the two groups. Buccal bone height loss in the MSE group had a negative correlation with initial buccal bone thickness.

CONCLUSIONS

The incorporation of teeth into bone-borne expanders resulted in an increase in the severity of side effects. For patients in late adolescence, tissue bone-borne expanders offer comparable skeletal effects to tooth bone-borne expanders, with fewer dentoalveolar side effects.

Midfacial changes in the coronal plane induced by microimplant-supported skeletal expander, studied with cone-beam computed tomography images

INTRODUCTION

Our objectives were to evaluate midfacial skeletal changes in the coronal plane and the implications of circummaxillary sutures and to localize the center of rotation for the zygomaticomaxillary complex after therapy with a bone-anchored maxillary expander, using high-resolution cone-beam computed tomography.

METHODS

Fifteen subjects with a mean age of 17.2 ± 4.2 years were treated with a bone-anchored maxillary expander. Pretreatment and posttreatment cone-beam computed tomography images were superimposed and examined for comparison.

RESULTS

Upper interzygomatic distance increased by 0.5 mm, lower interzygomatic distance increased by 4.6 mm, frontozygomatic angles increased by 2.5° and 2.9° (right and left sides), maxillary inclinations increased by 2.0° and 2.5° (right and left sides), and intermolar distance increased by 8.3 mm (P <0.05). Changes in frontoethmoidal, zygomaticomaxillary, and molar basal bone angles were negligible (P >0.05).

CONCLUSIONS

A significant lateral displacement of the zygomaticomaxillary complex occurred in late adolescent patients treated with a bone-anchored maxillary expander. The zygomatic bone tended to rotate outward along with the maxilla with a common center of rotation located near the superior aspect of the frontozygomatic suture. Dental tipping of the molars was negligible during treatment.

Effects of rapid maxillary expansion in cleft patients resulting from the use of two different expanders

Objective:

The aim of this study was to evaluate the skeletal and dental effects of rapid maxillary expansion (RME) in cleft patients using two types of expanders.

Methods:

Twenty unilateral cleft lip and palate patients were randomly divided into two groups, according to the type of expander used: (I) modified Hyrax and (II) inverted Mini-Hyrax. A pretreatment cone-beam computed tomographic image (T0) was taken as part of the initial orthodontic records and three months after RME, for bone graft planning (T1).

Results:

In general, there was no significant difference among groups (p > 0.05). Both showed a significant transverse maxillary expansion (p < 0.05) and no significant forward and/or downward movement of the maxilla (p > 0.05). There was greater dental crown than apical expansion. Maxillary posterior expansion tended to be larger than anterior opening (p < 0.05). Cleft and non-cleft sides were symmetrically expanded and there was no difference in dental tipping between both sides (p > 0.05).

Conclusions:

The appliances tested are effective in the transverse expansion of the maxilla. However, these appliances should be better indicated to cleft cases also presenting posterior transverse discrepancy, since there was greater expansion in the posterior maxillary region than in the anterior one.

Is alternate rapid maxillary expansion and constriction an effective protocol in the treatment of Class III malocclusion? A systematic review

Introduction:

the treatment of Class III malocclusion in early age is one of the greatest challenges for orthodontists, and the establishment of more effective treatment method is a constant concern for these professionals. Thus, the objective of this systematic review is to verify the effectiveness of the therapy protocol for alternate rapid maxillary expansion and constriction (Alt-RAMEC) in the early treatment of Class III malocclusion.

Methods:

searches were performed in the following electronic databases: Cochrane Library, Medline (EBSCO and PubMed), SciELO, LILACS and Scopus. The following inclusion criteria were used: in vivo studies conducted with early intervention (patient in craniofacial development phase) with the use of the Alt-RAMEC protocol. Reviews, case reports, editorials, and studies with syndromic patients or under use of systemic drug were excluded. Duplicates were also excluded. The studies were assessed for methodological quality using the Cochrane tool for assessment of risk of bias, and classified as high or low risk of bias.

Results:

53 articles were found. Duplicates exclusion was thus performed and 35 articles remained. After inclusion analysis, only 5 matched the criteria. Two articles were classified as low risk of bias and three as high risk of bias. It was observed that the Alt-RAMEC enable protraction in less time and with better results, promoting greater effectiveness in the protraction treatment of Class III malocclusion.

Conclusions:

Although there is positive evidence of the effectiveness of early treatment with the Alt-RAMEC protocol in patients with Class III malocclusion, further studies are needed to confirm its effectiveness using long-term methodology.

Relationship between voice function and skeletal effects of rapid maxillary expansion

OBJECTIVE

To evaluate the effects of rapid maxillary expansion (RME) on the vocal quality, maxillary central incisors, midpalatal suture, and nasal cavity in patients with maxillary crossbite.

MATERIALS AND METHODS

Coronal CT scans of 30 subjects (14 boys, 16 girls; mean age, 12.01 ± 0.75) were taken before RME (T0), and at the end of the expansion phase (T1). Voice samples of all patients were recorded with a high-quality condenser microphone (RODE NT2-A) on a desktop computer at T0 and T1. Statistical analyses were performed using a paired-sample t-test. The degree of association between the changes in the voice parameters and nasal width was assessed with Pearson's correlation.

RESULTS

RME treatment produced a significant increase in the transverse dimensions of the midpalatal suture and nasal cavity between T0 and T1 ( P < .05). The maximum F0 and jitter (%) results were shown to decrease statistically significantly from T0 to T1 ( P < .001 and P = .042, respectively). Between T0 and T1, shimmer (%) and shimmer (dB) exhibited statistically significant increases ( P = .037 and P = .019, respectively).

CONCLUSIONS

After RME therapy, voice quality differences were found to be associated with increases in nasal width.

Changes in the midpalatal and pterygopalatine sutures induced by micro-implant-supported skeletal expander, analyzed with a novel 3D method based on CBCT imaging

Background

Mini-implant-assisted rapid palatal expansion (MARPE) appliances have been developed with the aim to enhance the orthopedic effect induced by rapid maxillary expansion (RME). Maxillary Skeletal Expander (MSE) is a particular type of MARPE appliance characterized by the presence of four mini-implants positioned in the posterior part of the palate with bi-cortical engagement. The aim of the present study is to evaluate the MSE effects on the midpalatal and pterygopalatine sutures in late adolescents, using high-resolution CBCT. Specific aims are to define the magnitude and sagittal parallelism of midpalatal suture opening, to measure the extent of transverse asymmetry of split, and to illustrate the possibility of splitting the pterygopalatine suture.

Methods

Fifteen subjects (mean age of 17.2 years; range, 13.9–26.2 years) were treated with MSE. Pre- and post-treatment CBCT exams were taken and superimposed. A novel methodology based on three new reference planes was utilized to analyze the sutural changes. Parameters were compared from pre- to post-treatment and between genders non-parametrically using the Wilcoxon sign rank test. For the frequency of openings in the lower part of the pterygopalatine suture, the Fisher’s exact test was used.

Results

Regarding the magnitude of midpalatal suture opening, the split at anterior nasal spine (ANS) and at posterior nasal spine (PNS) was 4.8 and 4.3 mm, respectively. The amount of split at PNS was 90% of that at ANS, showing that the opening of the midpalatal suture was almost perfectly parallel antero-posteriorly. On average, one half of the anterior nasal spine (ANS) moved more than the contralateral one by 1.1 mm. Openings between the lateral and medial plates of the pterygoid process were detectable in 53% of the sutures (P < 0.05). No significant differences were found in the magnitude and frequency of suture opening between males and females. Correlation between age and suture opening was negligible (R² range, 0.3–4.2%).

Conclusions

Midpalatal suture was successfully split by MSE in late adolescents, and the opening was almost perfectly parallel in a sagittal direction. Regarding the extent of transverse asymmetry of the split, on average one half of ANS moved more than the contralateral one by 1.1 mm. Pterygopalatine suture was split in its lower region by MSE, as the pyramidal process was pulled out from the pterygoid process. Patient gender and age had a negligible influence on suture opening for the age group considered in the study.

Laser and LED phototherapy on midpalatal suture after rapid maxilla expansion: Raman and histological analysis

The aim of this study was to analyze the effect of laser or LED phototherapy on the acceleration of bone formation at the midpalatal suture after rapid maxilla expansion. Forty-five rats were divided into groups at 7 days (control, expansion, expansion and laser irradiation, and expansion and LED irradiation) and into 14 days (expansion, expansion and laser in the 1st week, expansion and LED in the 1st week, expansion and laser in the 1st and 2nd weeks, expansion and LED in the 1st and 2nd weeks). Laser/LED irradiation occurred every 48 h. Expansion was accomplished with a spatula and maintained with a triple helicoid of 0.020-in stainless steel orthodontic wire. A diode laser (λ780 nm, 70 mW, spot of 0.04 cm², t = 257 s, SAEF of 18 J/cm²) or a LED (λ850 ± 10 nm, 150 ± 10 mW, spot of 0.5 cm², t = 120 s, SAEF of 18 J/cm²) was applied in one point in the midpalatal suture immediately behind the upper incisors. Raman spectroscopy and histological analyses of the suture region were carried and data was submitted to statistical analyses (p ≤ 0.05). Raman spectrum analysis demonstrated that irradiation increases hydroxyapatite in the midpalatal suture after expansion. In the histological analysis of various inflammation, there was a higher production of collagen and osteoblastic activity and less osteoclastic activity. The results showed that LED irradiation associated to rapid maxillary expansion improves bone repair and could be an alternative to the use of laser in accelerating bone formation in the midpalatal suture.

Evaluation of rapid maxillary expansion through acoustic emission technique and relative soft tissue attenuation

OBJECTIVES

Acoustic emission (AE) is a non-destructive test to detect energy release. This technique was applied during rapid maxillary expansion (RME) to evaluate the reaction of the craniofacial skeleton.

MATERIALS AND METHODS

A swine model was analysed. Soft tissues were removed from two heads, while other two were preserved intact. A palatal expander (PE) was positioned and AE sensors were placed on the intermaxillary, fronto-nasal, and maxillo-lacrimal sutures. The PE was activated and AE recorded during RME. Differences between parameters were analysed with Mann-Whitney U test and Kruskal-Wallis test, and correlations with Spearman-Rho test (significance p<0.05).

RESULTS

PE activations were accompanied by clusters of AE hits. In the presence of soft tissues, amplitudes were generally lower (p<0.001) and durations were higher (p<0.001). No differences were found in the respective energy values. Differences were found in the AE (p<0.05) among the four channels, with AE characterised by higher values in proximity of the maxillo-lacrimal sutures. High-energy hits were represented by burst-type waves, and low-energy ones by continuous-type.

CONCLUSIONS

Although soft tissues create possible attenuation of the signal, AE can be detected during RME with sensors on the skin. AE provided further information of energy release, on top of the mechanical parameters. Source location was one of the main limitations.

Nonsurgical miniscrew-assisted rapid maxillary expansion results in acceptable stability in young adults

OBJECTIVE

To evaluate the stability of nonsurgical miniscrew-assisted rapid maxillary expansion (MARME) in young adults with a transverse maxillary deficiency.

MATERIALS AND METHODS

From a total of 69 adult patients who underwent MARME followed by orthodontic treatment with a straight-wire appliance, 20 patients (mean age, 20.9 ± 2.9 years) with follow-up records (mean, 30.2 ± 13.2 months) after debonding were selected. Posteroanterior cephalometric records and dental casts were obtained at the initial examination (T0), immediately after MARME removal (T1), immediately after debonding (T2), and at posttreatment follow-up (T3).

RESULTS

Suture separation was observed in 86.96% of subjects (60/69). An increase in the maxillary width (J-J; 1.92 mm) accounted for 43.34% of the total expansion with regard to the intermolar width (IMW) increase (4.43 mm; P < .001) at T2. The amounts of J-J and IMW posttreatment changes were -0.07 mm (P > .05) and -0.42 mm (P  =  .01), respectively, during retention. The postexpansion change in middle alveolus width increased with age (P < .05). The postexpansion change of interpremolar width (IPMW) was positively correlated with the amount of IPMW expansion (P < .05) but not with IMW. The changes of the clinical crown heights in the maxillary canines, first premolars, and first molars were not significant at each time point.

CONCLUSIONS

Nonsurgical MARME can be a clinically acceptable and stable treatment modality for young adults with a transverse maxillary deficiency.

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.

Evaluation and comparison of root resorption between tooth-borne and tooth-tissue borne rapid maxillary expansion appliances: A CBCT study

OBJECTIVE

To compare volumetric root resorption after rapid maxillary expansion (RME) between tooth-borne and tissue-borne appliances using CBCT. Repair in resorption cavities after 6 months of fixed retention was also compared.

MATERIALS AND METHODS

A sample of 33 subjects were randomly divided into two groups: Hyrax (n  = 16) and Haas (n = 17). CBCT scans were taken 6 months before expansion, immediately after expansion, and 6 months after fixed retention. Mimics Innovation V 16.0 software was used for segmentation and volumetric measurement of 198 teeth. Bland-Altman plots, independent samples t test, repeated measures analysis of variance, and the Friedman test were used for statistical analysis.

RESULTS

Differences in root resorption after RME and repair after retention were not significant between the hyrax and Haas appliances or between male and female. Significant differences were found between preexpansion and postexpansion root volumes in the first premolars and molars--even in unattached second premolars. When the percentage of root volume loss is considered, no significant difference was found between the first premolar, second premolar, and first molar. Volumetric changes after 6 months of retention were not statistically significant.

CONCLUSIONS

More resorption was observed in the Hyrax expander group. But it was not statistically significant. Repair was observed after 6 months of retention. Heavy RME forces affected premolars and molar similarly.

Comparison of tooth-borne and hybrid devices in surgically assisted rapid maxillary expansion: A randomized clinical cone-beam computed tomography study

PURPOSE

The objective of this 2-arm, parallel, single-center trial was to compare the skeletal, dental, and periodontal effects of tooth-borne (TB) and hybrid devices in surgically assisted rapid maxillary expansion (SARME).

MATERIALS AND METHODS

Twenty consecutive patients (9 male and 11 female) with skeletal transverse maxillary deficiency seeking treatment at the Department of Orthodontics at Istanbul University in Istanbul, Turkey, were randomly assigned to 2 groups (10 patients each). Hybrid devices were inserted in the first group and TB (Hyrax) devices in the second. All of the patients had undergone SARME operations, which were carried out by the same surgeons using the same procedure (a Le Fort I osteotomy with pterygomaxillary dysjunction). All of the patients had similar transverse deficits, and 7 mm of expansion was achieved in all of them over 14 days. CBCT was carried out preoperatively (T0), at the end of the active expansion phase (T1), and after 6 months of retention (T2). Measurements were made using Mimics 16.0.

RESULTS

Anterior skeletal maxillary widening parameters increased significantly in the T0-T1 and T0-T2 periods in the 2 groups (P = 0.001). There was significantly less dental expansion anteriorly with the hybrid devices (T0-T2: 4.03 mm vs. 6.29 mm). The first molars tipped buccally more in the group with TB devices during the T0-T1 phase (P = 0.029) and moved upright more than those in the group with hybrid devices during the retention phase (P = 0.035). Dental tipping, buccal alveolar bone resorption, and root resorption were observed significantly more often with the TB devices.

CONCLUSION

Hybrid RME devices, with similar skeletal effects, different dental movement patterns, and fewer dental and periodontal side effects, thus appear to be a beneficial alternative to TB devices for SARME procedures.

Viscoelastic response of the midpalatal suture during maxillary expansion treatment

OBJECTIVES

The viscoelastic response of the midpalatal suture during maxillary expansion treatment has been sparsely studied. The aim of our study was to use viscoelastic models to investigate the effect of appliance mechanics on sutural tissue.

MATERIALS AND METHODS

Four creep-strain models were utilized in predicting the midpalatal suture's response to a constant-force application during expansion treatment. The functional forms included a three-term separable, three-term inseparable, two-term inseparable, and single-term arrangement. The functions were then transformed into subsequent stress-relaxation representations to predict suture response as a result of 0.25, 0.20, 0.15, and 0.10 mm displacements. Finally, the single-term creep-strain representation was altered to simulate treatment decaying force during treatment. A force that decays 30 and 10% of an initially applied 0.98 N was considered for decaying functions over a 6-week period, and compared to strain resulting from a constant-force application.

RESULTS

This analysis illustrated that the decay in suture strain closely followed decay in force and that the path of decay had minimal impact on overall results. Also, it was found that a single screw activation would likely not cause suture soft tissue failure, even for a 0.25 mm displacement, and that suture stress rapidly decayed within minutes of activation.

CONCLUSION

Results from this study support the notion of maintaining a low-magnitude constant traction on the suture during treatment to avoid soft tissue failure and promote tissue remodeling.

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.