Dimensional Changes of Upper Airway after Rapid Maxillary Expansion: A Prospective Cone-beam Computed Tomography Study

Introduction: The aim of this prospective study was to use cone-beam computed tomography to assess the dimensional changes of the upper airway in orthodontic patients with maxillary constriction treated by rapid maxillary expansion. Methods: Fourteen orthodontic patients (mean age, 12.9 years; range, 9.7-16 years) were recruited. The patients with posterior crossbite and constricted maxilla were treated with rapid maxillary expansion as the initial part of their comprehensive orthodontic treatments. Before and after rapid maxillary expansion conebeam computed tomography scans were taken to measure the retropalatal and retroglossal airway changes in terms of volume, and sagittal and cross-sectional areas. The transverse expansions by rapid maxillary expansion were assessed between the midlingual alveolar bone plates at the maxillary first molar and first premolar levels. The measurements of the before and after rapid maxillary expansion scans were compared by using paired t tests with the Bonferroni adjustment for multiple comparisons. Results: After rapid maxillary expansion, significant and equal amounts of 4.8 mm of expansion were observed at the first molar (P 5 0.0000) and the first premolar (P 5 0.0000) levels. The width increase at the first premolar level (20.0%) was significantly greater than that at the first molar level (15.0%) (P 5 0.035). As the primary outcome variable, the cross-sectional airway measured from the posterior nasal spine to basion level was the only parameter showing a significant increase of 99.4 mm2 (59.6%) after rapid maxillary expansion (P 5 0.0004). Conclusions: These results confirm the findings of previous studies of the effect of rapid maxillary expansion on the maxilla. Additionally, we found that only the cross-sectional area of the upper airway at the posterior nasal spine to basion level significantly gains a moderate increase after rapid maxillary expansion

Maxillary expansion in an animal model with light, continuous force

Objectives: Maxillary constriction is routinely addressed with rapid maxillary expansion (RME). However, the heavy forces delivered by most RME appliances to expand the palate may lead to deleterious effects on the teeth and supporting tissues. The objective of this study was to explore a more physiologic maxillary expansion with light continuous force. Materials and Methods: Twenty 6-week-old Sprague-Dawley rats were equally divided into experimental (EXPT) and control (CTRL) groups. A custom-fabricated archwire expansion appliance made from 0.014-inch copper-nickel-titanium wire was activated 5 mm and bonded to the maxillary molar segments of animals in the EXPT group for 21 days. The force applied to each maxillary segment was 5 cN. Microfocus x-ray computed tomography and histological analyses were used to compare the tooth movement and bone morphology in the midpalatal suture and buccal aspect of the alveolar process between the EXPT and CTRL groups. Descriptive statistics (mean ± standard error of the mean) and nonparametric statistical tests were used to compare the outcomes across groups. Results: Compared to the CTRL group, there was a statistically significant increase in buccal tooth movement and expansion of the midpalatal suture in the EXPT group. There was no difference in the bone morphologic parameters between groups. The mineral apposition rate was increased on the buccal surface of the alveolar process in the EXPT group. Conclusions: Application of light, continuous force resulted in maxillary osseous expansion due to bilateral sutural apposition and buccal drift of the alveolar processes. This animal experiment provides a more physiologic basis for maxillary expansion

Slow maxillary expansion: a comparison between banded and bonded appliances

Various investigations have mentioned the use of a bonded maxillary expansion appliance. It was postulated that a full coverage of the occlusal surfaces by acrylic would remove interferences during the lateral displacement of the two maxillary bones and would lessen the resistance to maxillary expansion. The first objective of this study was to compare two appliances, a bonded and a banded Minne expander using a continuous force of two pounds, which would produce a slow maxillary expansion. The second objective was to evaluate the ratio between the skeletal and dental response to slow maxillary expansion, and to compare these results to those obtained with a rapid maxillary expansion procedure. Each experimental group consisted of 5 patients, aged between 8 and 12 years wearing the two different appliances. Prior to treatment they were implanted according to the Björk technique. The slow expansion period lasted 7 to 15 weeks followed by a retention period of 12 weeks. Post-retention observations followed 12 weeks after the end of retention. No significant difference was found between banded and bonded appliances in regard to dental and skeletal expansion and relapse. The amount of skeletal versus dental movements equalled results obtained with rapid maxillary expansion. The relapse tendency appeared lower than with rapid maxillary expansio

Retrospective CBCT analysis of airway volume changes after bone-borne vs tooth-borne rapid maxillary expansion

Objectives: To compare changes in upper airway volume after maxillary expansion with bone- and tooth-borne appliances in adolescents and to evaluate the dentoskeletal effects of each expansion modality. Materials and Methods: This retrospective study included 36 adolescents who had bilateral maxillary crossbite and received bone-borne maxillary expansion (average age: 14.7 years) or tooth-borne maxillary expansion (average age: 14.4 years). Subjects had two cone beam computed tomography images acquired, one before expansion (T1) and a second after a 3-month retention period (T2). Images were oriented, and three-dimensional airway volume and dentoskeletal expansion were measured. Analysis of variance was used to test for differences between the two expansion methods for pretreatment, posttreatment, and prepost changes. Paired t-tests were used to test for significance of prepost changes within each method. Results: Both groups showed significant increase only in nasal cavity and nasopharynx volume (P < .05), but not oropharynx and maxillary sinus volumes. Intermolar and maxillary width increased significantly in both groups (P < .05); however, the buccal inclination of maxillary molars increased significantly only in the tooth-borne group (P < .05). There was no significant difference between tooth- and bone-borne expansion groups, except for the significantly larger increase in buccal inclination of the maxillary right first molar after tooth-borne expansion. Conclusions: In adolescents, both tooth- and bone-borne RME resulted in an increase in nasal cavity and nasopharynx volume, as well as expansion in maxillary intermolar and skeletal widths. However, only tooth-borne expanders caused significant buccal tipping of maxillary molars

Changes in the Transverse Dimension of the Nasomaxillary Complex Following Rapid Palatal Expansion – a Post-Retention, CBCT Evaluation

Purpose: The purpose of this investigation was to evaluate the immediate and long-term effects of palatal expansion on the transverse dimension of the nasomaxillary complex. Materials and Methods: Twenty-eight patients’ CBCTs were obtained at four time points: pre-expansion (T1), post-expansion (T2), pre-treatment (T3), and middle or end of orthodontic treatment (T4). The patients’ age, sex, cervical vertebral maturation stage, and the number of instructed expander turns were recorded. Measurements of the nasal floor, nasal passage, maxillary sinus, maxillary first molar mesiolingual cusp, maxillary first molar palatal cusp, maxillary first molar buccal cortical bone, maxillary first molar palatal cortical bone, interorbital, and extraorbital widths were recorded. Results: During expansion, all parameters except interorbital and extraorbital widths increased significantly. Post-expansion, most parameters continued to increase, with only the cusp tip width decreasing significantly. There were no significant differences between males and females except nasal floor, nasal passage, and interorbital widths during expansion (T1 to T2). Pre-expansion growth status did not influence changes except the extraorbital width during orthodontic treatment (T3 to T4). Conclusions: Palatal expansion significantly changed the transverse width of nasomaxillary complex. Long-term retention showed all parameters except maxillary molar cusp and maxillary molar buccal cortical bone widths continued to increase to the T4 time point, likely due to the patients’ growth overcoming any relapse occurring

Nonsurgical Maxillary Expansion in Adults: Report of Two Cases

Correction of maxillary transverse discrepancy requires expansion&nbsp;of palate by combination of orthopedic and orthodontic&nbsp;movements. Isolated maxillary transverse deficiency can be&nbsp;treated either orthodontically or surgically with assisted rapid&nbsp;maxillary expansion (RME).&nbsp;Nonsurgical expansion modalities include rapid maxillary&nbsp;expansion and slow maxillary expansion. Haas popularized the&nbsp;idea of orthodontic palatal expansion in the 1960s, and since&nbsp;then transverse deficiencies have been treated successfully&nbsp;&nbsp;in children and adolescents.&nbsp;The use of palatal expanders in adults was widely frowned&nbsp;upon and was generally considered to be unsuccessful.&nbsp;Handelman published a clinical review in 1997, proving a nonsurgical&nbsp;expansion in adults was possible

Unilateral and bilateral corticotomies for correction of maxillary transverse discrepancies

Surgically-assisted rapid maxillary expansion in adults has been proved effective in overcoming the strong resistance of the maxillary complex after growth is completed, particularly after the second decade of life. The aim of this study was to describe the dental and the skeletal expansion and relapse, as well as the amount of tipping of the two maxillary bones and first permanent molars, during a rapid maxillary expansion procedure combined with unilateral and bilateral corticotomies. The sample consisted of four adult patients, two presenting with bilateral and two with unilateral cross-bite. Records were taken before and after rapid maxillary expansion, at the end of retention and at least 12 months post-retention. In the cases of bilateral cross-bite the same amount of skeletal expansion was observed on both sides. The angular changes measured at the upper first molars indicated important tipping on both sides, which tended to relapse moderately during the retention and post-retention period. Following unilateral surgery, the operated side showed more than twice the amount of skeletal expansion than the non-operated side. The angular changes presented twice as much tipping and relapse on the operated side. The results of this study demonstrate that unilateral cross-bites in adults can be corrected with unilateral corticotomy and rapid maxillary expansion using the contralateral non-operated side as anchorage. Stability appeared satisfactory in all case

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

BackgroundMini-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.MethodsFifteen subjects (mean age of 17.2&nbsp;years; range, 13.9-26.2&nbsp;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.ResultsRegarding 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&nbsp;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&nbsp;mm. Openings between the lateral and medial plates of the pterygoid process were detectable in 53% of the sutures (P&nbsp;&lt;&nbsp;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 (R 2 range, 0.3-4.2%).ConclusionsMidpalatal 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&nbsp;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

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