Littérature scientifique sur le sujet « Maxillary Skeletal Expander (MSE) »

ABSTRACT 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.

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

Objectives: The objectives of the study were to compare the skeletal, dentoalveolar, and periodontal changes between two types of microimplant-assisted rapid maxillary expansion appliances: The bone-anchored maxillary expanders (BAME) and the tooth-bone-anchored maxillary skeletal expander (MSE). Materials and Methods: Thirty-four patients with a transverse maxillary deficiency were divided into two groups; the first group (16 patients, average age 14.9 years) was treated with the MSE appliance, and the second group (18 patients, average age 13.8 years) was treated with the BAME appliance. Cone-beam computed tomography scans were taken at pre-treatment (T1) and immediately post-expansion (T2) to measure the changes in midpalatal suture opening, total expansion (TE), alveolar bone bending, dental tipping (DT), and buccal bone thickness. Data were analyzed using paired t-test and two-sample t-test. Results: Midpalatal suture separation was found in 100% of the patients in both groups. The TE at the first molar was 5.9 mm in the MSE group and 4.7 mm in the BAME group. The skeletal contributions were 56% and 83% of TE for the MSE and BAME groups, respectively. Significantly less dental buccal tipping and buccal bone loss were found with the BAME group. The midpalatal suture in both groups exhibited a parallel opening pattern in the axial plane. Conclusion: The use of BAME appliance resulted in greater skeletal effects, less dental tipping, and less buccal bone reduction compared to MSE appliance (immediately after maxillary expansion).

Background: To assess the changes in the inclination of the premolar and molar during a maxillary expansion with a micro-implant-assisted skeletal expander (MSE). Materials and Methods: A total of 21 patients (16 females, 5 males) with a mean age of 18.6 ± 4.5 (range 11.3–26.3 years) with a transverse maxillary deficiency were included in this study. They all received an MSE appliance for the maxillary skeletal expansion. The activation protocol consisted of about 0.5 mm expansion a day until a diastema was observed and continued with about 0.25 mm a day until the desired transverse relationship between the maxilla and mandible was achieved. OnDemand3D software was used for the measurements of the inclination change in the maxillary premolars and molars, pre- and post-expansion. Graphpad was used to compare the mean change in each tooth with the zero value (no change), and the p values of these changes with every tooth were calculated. Moreover, the changes and the mean values of all the teeth on the left and right sides were calculated separately. Results: A total of sixteen measurements were conducted for each patient. The first premolars tipped palatally after the expansion, while the second premolars and molars tipped buccally. The changes were significant for the molars and the left second premolar. Conclusions: The MSE induced some changes in the tooth inclination. The first premolars moved palatally, most likely due to perioral musculature and mastication force, while the first and second molars moved buccally. The second molar buccal movement is most likely due to the craniofacial rotation caused by the MSE as they were not subject to the expansion force.

Microimplant-assisted rapid palatal expansion (MARPE) has been demonstrated successfully in maxillary expansion in late adolescence and adulthood. The maxillary advancement accompanied by expansion is frequently anticipated, which is beneficial for the treatment of class III malocclusion. Airway volume increase can also be noted in some cases from the measurement of cone beam computerized tomography (CBCT) after expansion. The objective of this case report is to demonstrate the feasibility of applying MARPE on late adolescence patients with maxillary transverse deficiency and to present the changes in transverse and anteroposterior dimensions as well as the volume increase in velopharyngeal airway after MARPE. A 15-year-old female presented class III skeletal pattern. She had maxillary transverse deficiency with moderate crowding and posterior/anterior crossbites. Maxillary Skeletal Expander (MSE; Biomaterials Korea Inc.) type-2 was used as a MARPE device in this case. After four weeks of maxillary expansion, a significant amount of expansion was achieved and the anterior crossbite was spontaneously corrected. Fixed appliance treatment was commenced four weeks after MARPE with 0.022-slot preadjusted brackets (MBT prescription). Temporary anchorage devices (TADs) were placed over the mandibular buccal shelves for posterior teeth distalization and crowding relief. After 25 months of treatment, the facial profile was improved with maxillary advancement (SNA: 83° to 83.5°) and mandibular backward rotation (SNB: 83° to 82°; SN-MP: 34.5° to 35°). In this case, MARPE not only engenders significant transverse correction but also aids in anteroposterior change. The treatment effects of maxillary advancement and mandibular backward rotation can lead to a more esthetic profile in skeletal class III cases.

Transverse maxillary deficiency currently affects 8–23% of adults. One of the most widely used orthodontic treatments today in patients with transverse maxillary defects is the maxillary skeletal expander (MSE). This was a retrospective observational imaging study regarding structural bone changes that may occur during healing after the placement of micro-implant assisted rapid palatal expanders (MARPE) in combination with cortico-puncture (CP) therapy. Regarding the magnitude of the mid-palatal suture opening, the mean split at the anterior nasal spine (ANS) and the posterior nasal spine (PNS) was 3.76 and 3.12 mm, respectively. The amount of split at the PNS was smaller than at the ANS, approximately 85% of the distance, showing that the opening of the midpalatal suture was almost parallel in the sagittal plane. On average, one-half of the anterior nasal spine (ANS) moved more than the contralateral by 0.89 mm. In the present study, we show that MARPE associated with CP therapy had a positive outcome on the midpalatal suture opening. This occurred in safe conditions, without post-surgery bleeding, and showing healing at the corticotomy level, with no signs of swelling or sepsis, which are side effects usually associated with more complex surgical treatments. Our results suggest that non-surgical palatal expansion, assisted by MARPE and CP, is achievable and predictable in young adults.

This article reports two cases treated with a modified Miniscrew Assisted Rapid Palatal Expander (MARPE) that was fabricated in-office. Two female patients aged 15 years and 18 years were treated for maxillary expansion. An in-office modified GSR Expander was used. The appliance was secured in the patient’s maxillary arch using four miniscrews. Expansion was carried out for 4 weeks and 2 weeks respectively. Considerable opening of mid palatal suture with skeletal expansion was observed. An economical and effective alternative to stock made MARPE with better adaptability and clinical modifiability.

Objective The aim of this study was to evaluate skeletal and dentoalveolar changes before and after skeletal anchorage-assisted rapid palatal expansion in young adults by cone beam computed tomography. Materials and Methods This pilot study included ten patients with a mean age of 21.5 years with maxillary transverse deficiency treated with the skeletal expander. Three dimensional evaluation of the changes before and after expansion was evaluated with Cone Beam CT. Statistical analysis was performed using paired t-test. Results Skeletal expander produced an increase in maxillary transverse dimension at the skeletal, alveolar, and dental level. The maximum expansion was at the level of dentition, and the least amount of expansion was at the level of the frontonasal suture. There was also evidence of sutural divergence and buccal tipping. Conclusion The maxillary skeletal expander is an effective method for correction of maxillary transverse deficiency without surgery in adults.

ABSTRACT Objective: To determine if there is a significantly different effect on vertical changes during phase I palatal expansion treatment using a quad helix and a bonded rapid maxillary expander in growing skeletal Class I and Class II patients. Materials and Methods: This retrospective study looked at 2 treatment groups, a quad helix group and a bonded rapid maxillary expander group, before treatment (T1) and at the completion of phase I treatment (T2). Each treatment group was compared to an untreated predicted growth model. Lateral cephalograms at T1 and T2 were traced and analyzed for changes in vertical dimension. Results: No differences were found between the treatment groups at T1, but significant differences at T2 were found for convexity, lower facial height, total facial height, facial axis, and Frankfort Mandibular Plane Angle (FMA) variables. A comparison of treatment groups at T2 to their respective untreated predicted growth models found a significant difference for the lower facial height variable in the quad helix group and for the upper first molar to palatal plane (U6-PP) variable in the bonded expander group. Conclusion: Overall, both the quad helix expander and the bonded rapid maxillary expander showed minimal vertical changes during palatal expansion treatment. The differences at T2 suggested that the quad helix expander had more control over skeletal vertical measurements. When comparing treatment results to untreated predicted growth values, the quad helix expander appeared to better maintain lower facial height and the bonded rapid maxillary expander appeared to better maintain the maxillary first molar vertical height.

Introduction The aim of the present study is to evaluate the skeletal modifications induced by maxillary expansion supported by palatal micro-implants and localized osteotomies produced with minimally invasive surgical technique in young-adult and adult patients. In the present investigation, osteotomies had a lower extension than the ones used in conventional surgically assisted rapid palatal expansion (SARPE), to adopt a minimally invasive surgical technique that can be performed with greater comfort for the patient and less post-operative sequelae. More in detail, the localized osteotomies were executed only in the anterior part of the midpalatal suture and bilaterally at the basis of the zygomatic process of the maxilla without involvement of the piriform rim. These areas represent a great resistance to the lateral maxillary movement. Furthermore, they are of simple surgical access and don’t present important arterial plexuses. Patients requiring micro-implant supported maxillary expansion and/or SARPE routinely undergo a pre-treatment cone-beam computed tomography (CBCT) of the skull, to plan the surgical operation and, one month after treatment a secondary CBCT for a surgical and orthodontic control. CBCT is a low radiation tomography, extensively used in maxillofacial surgery and in dentistry. For the implementation of this study, that aims at evaluating the efficacy of micro-implant-supported maxillary expansion in combination with localized osteotomies, only radiologic exams that are anyway needed for the planning and post-treatment evaluation were used. Aim The aim of the present study is to evaluate the advantages introduced in the treatment of maxillary constriction by the therapy with micro-implant supported Maxillary Skeletal Expander (MSE) and localized osteotomies in young-adult and adult patients. The main objective is to evaluate the efficacy of the technique, by measuring the movement of skeletal landmarks in the midface, particularly on the maxillary and zygomatic bones, and on the lateral wall of the nose, by comparing the pre-treatment and post-treatment CBCT. For this particular technique, a new methodology for digital planning of position of MSE and miniscrews on patient CBCT was developed. Furthermore, incorporation of 2 additional miniscrews to the original MSE design, which conventionally features only 4 miniscrews, was developed with the aid of computer aided design – computer aided manufactured (CAD-CAM) technology. Methods The study presented the following steps: ▪ Development of a digital planning methodology for positioning the miniscrews and MSE appliance on pre-treatment CBCT ▪ Development of a CAD-CAM methodology for incorporating 2 additional miniscrews to the original MSE design with 4 miniscrews ▪ Selection of patients with age above 17 years, without congenital craniofacial syndromes, who require intervention of maxillary skeletal expansion ▪ Acquisition of initial CBCT with 17 x 13.5 cm field of view (FOV) ▪ Intervention of maxillary expansion supported by palatal micro-implants and localized osteotomies executed with minimally invasive surgical technique ▪ One month after treatment, acquisition of post-treatment CBCT with 17 x 13.5 cm FOV ▪ Analysis of skeletal modifications in the midface (maxillary bone, sphenoid bone, zygomatic arch, nasal cavity, etc.), by comparing the pre- and post- treatment CBCT with a 3D software (OnDemand software by Cybermed) Results The new methodology allowed the digital planning of MSE and miniscrews positioning on patients’ CBCTs, and the incorporation of two additional miniscrews to the original MSE design through CAD-CAM technology. In the clinical trial, a total of four patients had an average age of 27.6 years (range 22.1 – 39.9 years). MSE appliance was activated by an average of 6.0 mm and generated a parallel split of the midpalatal suture of 3.4 mm, 3.0 mm and 3.6 mm at anterior nasal spine (ANS), nasopalatine foramen (NPF) and posterior nasal spine (PNS), respectively. Skeletal modifications were found in all CBCT sections evaluated in the study (axial palatal, upper nasal, coronal zygomatic, axial zygomatic), indicating that all midfacial bones are affected by maxillary expansion with MSE and localized osteotomies. Particularly, skeletal changes were noticed also in CBCT sections above the lateral maxillary osteotomies (LMOs), in the maxilla, zygomatic bone, zygomatic arches, and nasal cavity. In the upper nasal section (UNS) the maxilla was laterally displaced by 2.4 mm and 0.9 mm, at its anterior and posterior extremities, respectively. The frontozygomatic angle (FZA) increased by 1.9° (average of right and left side), while the lower interzygomatic distance increased by 2.9 mm, indicating a rotation of the zygomatic bone in a lateral direction. The zygomatic arch was affected by bone bending phenomena and was deflected in an outward direction, with increase in the anterior intermaxillary distance by 1.7 mm and in the posterior inter-zygomatic distance by 1.6 mm. The nasal width (NW) parameter increased by 2.9 mm with treatment: this anatomical finding is the basis for a potential improvement in nasal breathing for patients suffering from increased nasal airway resistance. The cited modifications in skeletal structures above lateral maxillary osteotomies (LMOs) are most likely due to the fact that LMOs didn’t involve the piriform rim of the maxilla, and this point needs further investigations. Regarding dentoalveolar modifications, the inter-molar distance increased by 7.4 mm, and molars underwent a small dentoalveolar tipping in a buccal direction by 1.1° (average of right and left side), as evidenced by the change in molar basal bone angle (MBBA). No intra-operatory hemorrhage nor post-operatory bleeding was reported in treated patients, probably due to the lack of pterygopalatine suture surgical disjunction. A limitation of the study is its small sample size, represented by 4 patients. A larger number of patients is required to confirm the above results.

碩士
國立陽明大學
臨床牙醫學研究所
92
Rapid maxillary expansion (RME) of the constricted maxilla is an important part of the clinician’s armamentarium in the correction of posterior crossbite. Early correction of transverse problem has been advocated to obtain beneficial dental and skeletal changes during growth periods and involves a reduced treatment complexity. However, due to the limited tooth number and erupting sequence, it is necessary to modify the design of expander. For example, 2-band instead of 4-band is used in Hyrax expander. The purpose of this study was to compare the maxillary skeletal and dental changes between treatment groups using 2-band or 4-band expander. 24 preadolescent cases with maxillary constriction and posterior crossbite were involved in this study. The 2-band group consisted of 15 cases (8 males and 7 females, age: 9.39 + 2.28 years ) and the 4-band group consisted of 9 cases (2 males and 7 females, age: 11.63 + 1.64 years ) in the mixed dentition period. The treatment outcomes were evaluated with pretreatment and posttreament study casts and anterioposterior cephalometric films. Both groups showed significant skeletal and dental effects. There were significantly greater expansions in molar and premolar cusp widths in 4-band group. However, there were no significant differences in other dental and skeletal changes. There were also no differences in relative skeletal and dental changes to the increases in first molar width between two groups. In summary, 2-band expander has similar skeletal and dental effects as conventional 4-band expander.

The purpose of this research was to compare skeletal and dental changes assessed by digital volumetric images produced during and after rapid maxillary expansion (RME) between a bone-borne anchored expansion appliance and a conventional tooth-borne RME. Initial steps included the development of a methodology to analyze CBCT images. Reliability of traditional two dimensional (2D) cephalometric landmarks identified in CBCT images was explored, and new landmarks identifiable on the CBCT images were also evaluated. This methodology was later tested through a clinical trial with 62 patients where skeletal and dental changes found after maxillary expansion using either a bone-borne or tooth-borne maxillary expander and compared to a non-treated control group. The conclusions that were obtained from this thesis were that the NewTom 9” and 12” three dimensional (3D) images present a 1-to-1 ratio with real coordinates, linear and angular distances obtained by a coordinate measurement machine (CMM). Landmark intra- and inter-reliability (ICC) was high for all CBCT landmarks and for most of the 2D lateral cephalometric landmarks. Foramen Spinosum, foramen Ovale, foramen Rotundum and the Hypoglossal canal all provided excellent intra-observer reliability and accuracy. Midpoint between both foramen Spinosums (ELSA) presented a high intra-reliability and is an adequate landmark to be used as a reference point in 3D cephalometric analysis. ELSA, both AEM and DFM points presented a high intra-reliability when located on 3D images. Minor variations in location of these landmarks produced unacceptable uncertainty in coordinate system alignment. The potential error associated with location of distant landmarks is unacceptable for analysis of growth and treatment changes. Thus, an alternative is the use of vectors. Selection of landmarks for use in 3D image analysis should follow certain characteristics and modifications in their definitions should be applied. When measuring 3D maxillary complex structural changes during maxillary expansion treatments using CBCT, both tooth-anchored and bone-anchored expanders presented similar results. The greatest changes occurred in the transverse dimension while changes in the vertical and antero-posterior dimension were negligible. Dental expansion was also greater than skeletal expansion. Bone-anchored maxillary expanders can be considered as an alternative choice for tooth-anchored maxillary expanders.
Medical Sciences in Orthodontics