Stability of surgically assisted rapid maxillary expansion and orthopedic maxillary expansion after 3 years' follow-up

Objective:To evaluate the stability of surgically assisted rapid palatal expansion (SARME) and orthopedic maxillary expansion (OME) after 3 years of follow-up, and compare these changes with a control group.Materials and Methods:The subjects of the study were divided into three groups. Group 1 was composed of 10 patients (6 males, 4 females) with a mean age of 15.51 years (range: 13.33–17.58 years) and treated with OME, Group 2 comprised 10 patients (7 males, 3 females) with a mean age of 19.01 years (range: 16.25–25.58 years) and treated with SARME. Group 3 was the control group, consisting of 10 untreated, skeletal Class 1 subjects (6 males, 4 females) with a mean age of 15.27 years (range: 13.42–17.00 years) and matched to the OME group for sex and age. Lateral cephalometric and posteroantererior films were taken before expansion (T1), postexpansion (T2), and 3 years after the retention period (T3).Results:After OME and SARME, significant increases were observed for both dental and skeletal transverse widths (P < .01). After 3 years of follow-up, maxillary basal width decreased 1.35 ± 0.44 mm in the SARME group and 1.19 ± 0.41 mm in the OME group, while upper molar width decreased 2.23 ± 1.24 mm in the SARME group and 2.79 ± 1.01 mm in the OME group.Conclusions:Both the OME and SARME procedures remained stable after 3 years of follow-up with some amount of postretention relapse, compared with the control group.     

Stability and surgical complications of tooth-borne and bone-borne appliances in surgical assisted rapid maxillary expansion: a systematic review

The objective of this systematic review was to evaluate the stability and complications of tooth-borne (TB), bone-borne (BB) and hybrid (TB-BB) appliances in surgically assisted rapid maxillary expansion (SARME). Database searches were conducted (PubMed, Embase, Cochrane Library and SciELO), as well as a grey literature search (Google Scholar) and hand searches of reference lists. Forty-six articles were included after study selection (κ = 0.854). After eligibility assessment, 16 articles and one article from the grey literature were processed (κ = 0.866) and six articles were selected by hand searching, for a total of 23 articles included. Regarding stability, TB appliances showed width relapse rates ranging from 4 to 35% in canines, from 1 to 37% in premolars and from 0.2 to 49.5% in molars. In BB appliances, width relapse rates were 1.7-21% in canines, 1.5% in premolars and 4.6-11.5% in molars. In hybrid appliances, the width relapse rate was 14% in premolars, with a 1.8% overexpansion reported in the molar region. In TB and BB appliances, skeletal relapse rates were similar on the nasal floor (11-53% and 41.6%, respectively) and at the level of the maxilla (18% and 16%, respectively). The most common complications were bone resorption in TB appliances (18.14%) and appliance-related complications in BB appliances (17.9%). The risk of bias was high in 19 studies, medium in three studies and low in one study. The TB and BB appliances used in SARME were considered to have a high long-term stability. BB appliances appeared to have fewer relapses than TB appliances due to a more parallel distribution of forces exerted. However, relapse appears to be highly influenced by postorthodontic treatments, where arch-form coordination is achieved in the consolidation period with the purpose of overexpansion correction, alignment and final vertical adjustments. Further randomised controlled trials with long-term data and large sample sizes are needed to support evidence-based clinical decision-making and to allow meta-analytic studies of stability outcomes regarding the type of anchorage in SARME.     

The dawn of rapid maxillary expansion.

The first report of lateral maxillary expansion by separation of the maxilla, written by Angell and published in 1860, was discredited. Applying our present-day knowledge of the technique to the original documents indicates that the case history agrees in general with current observations. The arguments mounted against Angell, especially by McQuillen, may be dismissed as irrelevant and Angell's thesis is upheld. In addition, good reason exists to accept three further "firsts" in this unprecedented work: (1) The significance of the first permanent molars in occlusal development, (2) the use of a double-action jackscrew, and (3) the use of a retention plate.     

Surgically-assisted maxillary expansion

A combined surgical and orthodontic technique for management of transverse maxillary deficiencies in mature patients is described and discussed. Special references are made to the surgical release of several circummaxillary articulations to facilitate the use of a fixed expansion device, and to the authors' addition of an osteotomy below the nasal spine, to ensure that the nasal septum remains independent of the maxillary segments. Indications for the use of this surgically-assisted maxillary expansion technique, and its advantages when compared with segmented surgical expansion, are also presented.     

Surgically assisted rapid maxillary expansion compared with orthopedic rapid maxillary expansion

The objective of this study is to evaluate and compare the dental and skeletal changes occurring during orthopedic rapid maxillary expansion (RME) and surgically assisted RME during the active phase of treatment. The study was divided into two groups. The first group of 10 patients (six males, four females; mean age, 15.51 years) received orthopedic RME. The second group of 10 patients (seven males, three females; average age: 19.01 years) received surgically assisted RME (SARME). All patients underwent maxillary expansion with occlusal-coverage Hyrax-type expanders activated two turns a day (0.25 mm per turn). Preexpansion and postexpansion lateral and posteroanterior cephalograms were obtained for each patient. Statistically significant differences between the SARME and RME groups were found in the N-ANS, SN/ PP (P < .01) and SNA, SNB, mandibular dentoalveolar, and maxillary bony base (P < .05) measurements. Clinically, there is no difference in patient response between the RME and SARME groups. The only difference between the groups was their indication for RME or SARME, which is based on the age and skeletal maturation of the patient.     

The biomechanics of rapid maxillary sutural expansion.

Micro-displacements (fringe patterns) in the bones of the craniofacial complex as seen through laser holography during midpalatal sutural expansion with the Hyrax appliance are used to define the centers of rotation of the maxillary halves in both the frontal and occlusal views. Biomechanical analyses of the maxillary expansion force system are concomitant with the holographic findings and strongly suggest that the stainless steel wires joining the teeth to any expansion device be of the largest diameter possible. In addition, in the case of the Hyrax expansion device, it is recommended that the manufacturer increase the diameter of the activating screw as well as those of the 2 adjacent wire guides. And, importantly, the use of acrylic as a structural member to join the teeth to a sutural expansion device should be avoided if tipping of the maxillary halves is to be minimized, as the acrylic lacks sufficient rigidity.     

Removable rapid maxillary expansion

A novel removable rapid maxillary expansion appliance is described for use in routine clinical practice. The laboratory construction and clinical technique is described, and the advantages of the appliance over conventional rapid expansion devices are highlighted.     

Surgically assisted maxillary expansion

Orthodontic expansion of the maxilla can be facilitated by bone cuts through the zygomatic-alveolar process and in the palate lateral of the nasal septum. Stability of the surgical-orthodontic treatment outcome depends on the equilibrium of forces of the tongue and cheeks (functional envelope). Long term, even lifetime, retention is advised.     

Surgically assisted rapid maxillary expansion in adults.

Twelve adults with maxillary width discrepancy of greater than 5 mm were treated by surgically assisted rapid maxillary expansion. The procedure consisted of bilateral zygomatic buttress and midpalatal osteotomies combined with the use of a tooth-borne orthopedic device postoperatively. Mean palatal expansion of 7.5 mm (range of 6 to 13 mm), measured in the first molar region, was achieved within 3 weeks in all patients. Expansion remained stable during the 12-month study period, with a mean relapse for the entire group of 0.88 +/- 0.48 mm. Morbidity was limited to mild postoperative discomfort. The results of this preliminary study indicated that surgically assisted rapid maxillary expansion is a safe, simple, and reliable procedure for achieving a permanent increase in skeletal maxillary width in adults. Further study is necessary to document the three-dimensional movements of the maxillary segments and long-term stability of the skeletal and dental changes.     

The stability of maxillary expansion

The assessment and treatment by rapid maxillary expansion of 516 cases referred by medical practitioners for the treatment of poor nasal airway is reported. The technique is simple and most suitable for the correction of crossbite and Class III malocclusion and for establishing a nasal airway in habitual mouth breathers with a history of ENT problems.     

Rapid maxillary expansion and surgically assisted rapid maxillary expansion effects on nasal volume

The purpose of this study was to compare the effects of rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME) on nasal volume using acoustic rhinometric methods. Two groups of subjects were used in the study. Group 1 consisted of 10 subjects (mean age 12.30 +/- 0.82 years) who were treated with RME, and group 2 consisted of 10 subjects (mean age 18.70 +/- 2.54 years) who were treated by SARME. In both groups, all cases had a maxillary width deficiency with bilateral crossbites. Nasal volume records were taken by the same otorhinolaryngologist with an AR device. AR recordings were performed for each patient with and without the use of a decongestant. The first record was taken before expansion, and the second record was taken at the end of retention. The data for both groups were evaluated using Wilcoxon signed rank test and Mann-Whitney U-test. The nasal volume showed a significant increase in both the RME and the SARME groups (P < .05). The measurement with the use of decongestant was similar to that without use of decongestant on the both groups (P < .05), but the different increments in nasal volume between the RME and the SARME groups were not statistically significant. Although the mean ages between the RME and the SARME groups were different, the increase in nasal volume was similar in both groups.     

上颌快速扩弓的生物力学研究进展

上颌快速扩弓是临床上常用的治疗方法。上颌骨邻近组织结构复杂,而快速扩弓的矫治力作用于牙和腭部再通过骨和软组织的传导分散到整个上颌骨及其周围组织,因此其生物力学作用机制亦十分复杂。下面就其生物力学原理的国内外研究进展进行综述,以期对临床医师应用该法有所帮助。     

Transpalatal distraction as a method of maxillary expansion.

Conventional devices used for surgically assisted rapid palatal expansion are tooth-borne. Dental fixation entails a number of possible drawbacks such as loss of anchorage, skeletal relapse during and after the expansion period, cortical fenestration and buccal root resorption. A bone-borne titanium device with interchangeable expansion modules, used with a callous distraction policy, is presented.