Arch Expansion Research Articles

Arch expansion with the Invisalign system: Efficacy and predictability.

BackgroundIn adult patients, treatment of skeletal crossbite requires combined treatment by fixed or removable appliances and orthognathic surgery. In cases of dentoalveolar crossbite, expansion can be achieved with fixed multibrackets and removable transparent aligners. Various researchers have already assessed the Invisalign system’s predictability for arch expansion. However, most of this research was conducted using older appliances, making it necessary to assess the characteristics of the updated system SmartTrack.Material and methodsA sample of 114 patients with transverse malocclusion were treated with SmartTrack. The predictability of the system’s software (Clincheck) was assessed by comparing planned measurements (width of canines, premolars and molars rotations and inclinations) with the real measurements achieved at the end of the first treatment phase. Measurements were imported to Clincheck software to create three data sets; T1: initial measurements at start of treatment; T2: Clincheck predicted measurements at end of first treatment phase; T3: measurements taken at start of the second treatment phase.ResultsWidths underwent significant advances as a result of treatment. For all widths, virtual planning obtained prognoses of greater expansion than actually achieved: a mean of 0.63 mm more expansion at the canine level (p<0.001), 0.77 mm at first premolar (p<0.001), 0.81 at second premolar (p<0.001), 0.69 mm at first molar (p<0.001), and 0.25 mm at second molar (p = 0.183). All the treatment plan’s estimations, with the exception of the second molar, were significantly higher than the actual outcomes.ConclusionsAligners are an effective tool for producing arch expansion, being more effective in premolar area and less effective in canine and second molar area. Predictability was reasonable for expansion movement. Overcorrection should be considered at the virtual planning stage in order to obtain the expected outcomes.

Alveolar bone defects in adults reporting for orthodontic treatment - A CBCT study

Identifying alveolar bony fenestration and dehiscence preceding orthodontic treatment, especially arch expansion, is needed. An unrevealed and undiagnosed buccal alveolar bone defect leads to treatment relapse and further loss of bony support. The aim of this study was to determine the extent of posterior alveolar bony dehiscence and fenestration in adults undergoing orthodontic treatment. A total of 20 subjects in the age range 18-35 years were selected for this study randomly and their CBCT records were retrieved from the Department of Orthodontics, Saveetha dental college. All statistical analysis was performed using SPSS. Chi-square test was used to determine the association of extent of fenestrations and dehiscence between males and females. Females presented with wider and extensive dehiscence defects than males (p=0.019, p&lt;0.05). On the other hand, there was a statistically non-significant association of fenestration severity between males and females. (p=0.178, p&gt;0.05) Within the limits of this study, it was observed that females presented with more severe bony alveolar dehiscence than males.

Periodontal Grafting in Preparation for Orthodontic Treatment

Alveolar boundaries dictate the limitations of orthodontic tooth movement. Evaluation of the hard and soft tissues in terms of quality and quantity in conjunction with a sound orthodontic treatment plan that includes the amount and direction of desired tooth movement is essential. Prophylactic intervention may be required to support orthodontic goals and objectives without undesired iatrogenic periodontal consequences. The purpose of this article is to provide a review on current methods utilized for augmentation procedures prior to orthodontic treatment. Orthodontic treatment can have a significant impact on periodontal health. Increased demands by patients for non-extraction treatment and for camouflaged treatment of skeletal discrepancies to avoid orthognathic surgery can place challenges on orthodontists. Dental arch expansion and placing teeth beyond biologically acceptable limits can result in unfavorable periodontal outcomes, such as the development of fenestrations and dehiscences. Phenotype modification therapy via soft and/or hard tissue augmentation may expand the range of orthodontic movement without the risk of undesired periodontal outcomes during orthodontic treatment.

A SURVEY OF RETENTION PROTOCOLS AND TRENDS PRACTICED BY ORTHODONTISTS FROM CENTRAL INDIA: AN OBSERVATIONAL STUDY

Introduction: Retention is necessary following orthodontic treatment to prevent relapse of the final occlusal outcome. So the aim of the study is to evaluate retention procedures and protocols which are used by the Orthodontists from Central India. Methodology: In this study a total of 128 Orthodontists practicing from Central India were sent questionnaire which consisted of questions regarding different types of conditions or orthodontic treatment and the choice of retainer they would prefer.the questions were so designed to know which retainer would they prefer among both the arch. Also to know which type of retainer (removable or fixed) they prefer for certain conditions. Result:A combination of fixed and removable retainers were commonly used by Orthodontists in both the dental arches, except after expansion of the upper arch when removable retainer was preferably used, and after the correction of rotation of mandibular anterior teeth where in Orthodontists chose fixed retainer over removable. Hawleys retainer was most preferred for upper arch (71.9%), Vaccum formed retainer for the lower arch (49.2%). In the fixed retainer bonded to all the anteriors was most preferred (76.6%) in the lower arch while bonded to Central Incisors in the upper arch (80.5%). Conclusion: The Hawley appliance was a predominant removable retainer. The bonded wire from canine to canine was the most frequent fixed retainer. Evidence-based guidelines are required for drawing a common retention protocol.

Effects of Different Ligation Systems on Arch Expansion, Incisor Inclination and Treatement Duration in Patients with Mild to Moderate Crowding Patients- A Prospective Study

Effects of Different Ligation Systems on Arch Expansion, Incisor Inclination and Treatement Duration in Patients with Mild to Moderate Crowding Patients- A Prospective Study

Characterisation of arch expansion of cement stabilised road bases

ABSTRACT The arch expansion of cement stabilised base materials has become increasingly serious due to the current design guideline, typical climate and geological environment in the west of China. This research systematically investigated the influence of different factors on temperature expansion and also salt expansion of the cement stabilised base course through laboratory-scale slab tests and microscopic tests. Optimised gradation type of aggregate and other design indexes were proposed. The radial basis function network (RBFN) was used to establish a predication model of the amount of arch expansion. The micro-mechanism of arch expansion was further detailed by scanning images. The test results showed that the temperature expansion occurred most significantly during 20°C to 40°C and the optimised gradation could alleviate the arch expansion effectively. In the range of 20°C to 30°C, the arch expansion of cement stabilised materials was dominated by temperature expansion, and the expansion was mainly salt expansion between −10°C and 0°C. It is suggested that reasonable prevention measures should be taken considering different environmental factors by the inhibition weight 1/d i , and thus the most effective preventing methods of arch expansion would be taken.

Influence of Temperature and Sodium Sulfate Content on the Compaction Characteristics of Cement-Stabilized Macadam Base Materials.

This paper describes an experimental investigation into the compaction characteristics of cement-stabilized macadam base materials (CSMBM) in a saline soil area. Through the field tests, the main causes of arch expansion in an existing road were analyzed. Based on this, the compaction tests and microscopic tests were designed to analyze the impacts of temperature, sodium sulfate content and cement content on the compaction characteristics of CSMBM. Then, the orthogonal test was designed to analyze the effects of the degree of the temperature, the cement content, and the sodium sulfate content on the compaction results of the CSMBM. Feld tests results show that the temperature, sodium sulfate content and cement content may be the main causes of arch expansion. The compaction tests show that with the temperature increasing, the optimal water content (OWC) decreases, but the maximum dry density (MDD) increases; with the sodium sulfate content increasing, the OWC increases, but the MDD decreases; with the cement content increasing, both MDD and OWC increase. The microscopic tests show that the increase of temperature and cement content is beneficial to the compactness between cementitious materials and aggregates, while the increase of sodium sulfate content makes the whole structure of cementitious materials and aggregates increasingly rough. The orthogonal test shows that the temperature has the greatest influence on the MMD, and the sodium sulfate content has the greatest influence on the OWC. Thus, in a sulfate saline soil area, the construction temperature, the sodium sulfate content and the cement content should be controlled to ensure the compaction quality of CSMBM.

Comparison of Mandibular Arch Expansion by the Schwartz Appliance Using Two Activation Protocols: A Preliminary Retrospective Clinical Study.

Background and objectives: Dental crowding is more pronounced in the mandible than in the maxilla. When exceeding a significant amount, the creation of new space is required. The mandibular expansion devices prove to be useful even if the increase in the lower arch perimeter seems to be just ascribed to the vestibular inclination of teeth. The aim of the study was to compare two activation protocols of the Schwartz appliance in terms of effectiveness, particularly with regard to how quickly crowding is solved and how smaller is the increasing of vestibular inclination of the mandibular molars. Materials and Methods: We compared two groups of patients treated with different activation’s protocols of the lower Schwartz appliance (Group 1 protocol consisted in turning the expansion screw half a turn twice every two weeks and replacing the device every four months; Group 2 was treated by using the classic activation protocol—1/4 turn every week, never replacing the device). The measurements of parameters such as intercanine distance (IC), interpremolar distance (IPM), intermolar distance (IM), arch perimeter(AP), curve of Wilson (COW), and crowding (CR) were made on dental casts at the beginning and at the end of the treatment. Results: A significant difference between protocol groups was observed in the variation of COWL between time 0 and time 1 with protocol 1 with protocol 1 subjects showing a smaller increase in the parameter than protocol 2 subjects. The same trend was observed also for COWR, but the difference between protocol groups was slightly smaller and the interaction protocol-by-time did not reach the statistical significance. Finally, treatment duration in protocol 1 was significantly lower than in protocol 2. Conclusion: The results of our study suggest that the new activation protocol would seem more effective as it allows to achieve the objective of the therapy more quickly, and likely leading to greater bodily expansion.

Treatment Efficacy of Invisalign: Literature Review Update

Purpose: Inconsistency between computer prediction and actual tooth movement in Invisalign treatment always limits clinical judgment. The objective of this review was to update the evidence on the treatment efficacy of the Invisalign appliance. Material and Methods: Medical databases were screened for relevant peer-reviewed articles from 2000 to 2018 for the use of Invisalign as a treatment intervention. All human studies other than case reports and case series were included. Results: A total of 25 articles (4 RCTs, 6 prospective cohort studies, 15 retrospective cohort studies) were included. Treatment outcomes have been improving over the past 17 years. Invisalign treatment achieved results comparable with those of fixed appliances in extraction cases, except for buccolingual inclination (p<0.005) and occlusal contacts (p<0.001). For specific tooth movement, the highest accuracy was for arch expansion (upper: 72.8%, lower: 87.7%) and molar distalization (87%). Rotation of rounded tooth and overbite control with aligners was unpredictable. Conclusions: Invisalign treatment for controlling buccolingual inclination and occlusal contacts were less than ideal. None of the tooth movement was completely in line with predictions. Auxiliary or revised prescription may be needed to achieve high-quality results. Because the material, treatment design, and evaluation methods differ among studies, results should be interpreted carefully.

Is the corticotomy assisted orthodontic treatment efficient in the expansion of narrow arches in adult patients?

Corticotomy assisted orthodontic treatment (CAOT) is a technique which, performing surgical cuts on the cortical alveolar bone around the teeth, induces a faster rate of orthodontic tooth movement. The development CAOT offers solutions to overcome many of limitations in adult orthodontic treatment, such as risk of hyalinization, root resorption, periodontal problems, lack of bone growth and a long therapy time due to slower tooth movement compared to adolescents. The purpose of this systematic review was to identify if CAOT is also useful for expanding narrow arches in adult orthodontic patients. An electronic research on PubMed until June 2020 was made with the combined search terms "corticotomy expansion," "corticotomy orthodontic expansion" and "corticotomy orthodontic." Six studies were included in this systematic review. The authors found discordant results in literature; however, it seems that CAOT can have better results than conventional expansion, but it cannot be considered as an alternative therapy for severe posterior cross-bite. CAOT have a greater predictability if done with bone grafting. The evidence of corticotomy as a help to palatal expansion in adult orthodontic treatment has not been well described in literature and only few published reports are available. Further testing in human beings are still necessary to confirm the validity of this technique.

The biomechanics of posterior maxillary arch expansion using fixed labial and lingual appliances.

To compare the biomechanics of straight labial, straight lingual, and mushroom lingual archwire systems when used in posterior arch expansion. An electro-mechanical orthodontic simulator allowing for buccal-lingual and vertical displacements of individual teeth and three-dimensional force/moment measurements was instrumented with anatomically shaped teeth for the maxillary arch. In-Ovation L brackets were bonded to lingual surfaces, and Carriere SLX brackets were bonded to labial surfaces to ensure consistency of slot dimensions. Titanium molybdenum archwires were bent to an ideal arch form, and the teeth on the orthodontic simulator were set to a passive position. Posterior teeth from the canine to second molar were moved lingually to replicate a constricted arch. From the constricted position, the posterior teeth were simultaneously moved until the expansive force decreased below 0.2 N. Initial force/moment systems and the amount of predicted expansion were compared for posterior teeth at a significance level of α = 0.05. Archwire type affected both the expected expansion and initial force/moment systems produced in the constricted position. In general, the lingual systems produced the most expansion. The archwire systems were not able to return the teeth to their ideal position, with the closest system reaching 41% of the intended expansion. In general, lingual systems were able to produce greater expansion in the posterior regions when compared with labial systems. However, less than half of the intended arch expansion was achieved with all systems tested.

Morphometric analysis of dental arch form changes in classII patients treated with clear aligners.

The purpose of this study was to evaluate the arch form changes in classII Caucasian patients treated with Invisalign® (Align Technology, San José, CA, USA). A total of 27classII patients, for whom amaximum of 4 mm arch expansion was planned, were selected. Both maxillary and mandibular digital casts were compared at three different times: pretreatment (T0), accepted set-up (T1), and retention phase (T2). Each digital model was imported into GOM Inspect© software (GOM GmbH, Braunschweig, Germany) to identify teeth crown facial axis (FA) and cusp points to create acoordinate system. In each model the origin of the coordinates was located at the contact point of central incisors and asystem of Cartesian axes was constructed. Using the FA points, an average arch form was obtained for each clinical step and then the following comparisons were performed for each class group: T0-T1, T0-T2, and T1-T2. T1 showed wider maxillary and mandibular dental arches compared to T0 with maximum movements observed in the premolar regions (maximum movement 1.94 mm for tooth15; P < 0.0001). In the T1-T2 comparison, amore buccal position of tooth22, tooth23, and tooth24 (maximum movement 0.56 mm; P < 0.05) and amore lingual position of tooth37 (maximum movement 0.81 mm; P < 0.01), tooth36, and tooth47 were observed at T1 with respect to T2. Although Invisalign® treatment resulted in asignificant increase in arch width according to the prescription, some of the outcomes were different than those planned especially in relation to the final position of the lower molars.

Upper canine response to rapid maxillary expander anchored to deciduous vs. permanent molars.

To understand whether two different designs of Haas-type rapid maxillary expander (H‑RME) might have adifferent influence on canine eruption. In all, 108 subjects seeking orthodontic treatment were selected and divided into two groups-H‑RME with bands on the upper second deciduous molars (GrE), H‑RME with bands on the upper first permanent molars (Gr6)-and were also compared to an historical untreated control group (CG) of 29subjects. Panoramic x‑rays (OPG) were performed before and after RME (T0-T1: 16 ± 7months) and the upper canine angulation to the midline ("α"angle) was measured on both pre- and posttreatment OPG. Asignificant improvement of the canine position (decrease of the αangle) following RME in subjects with mixed dentition was reported in both treated groups, although the different design of the RME did not significantly affect canine angulation. Canine angulation in untreated subjects with transversal discrepancy did not improve significantly. Using RME in the early mixed dentition appears to be an effective procedure to increase the rate of eruption of maxillary canines, but the position of the bands on the upper second deciduous molars or on the upper first permanent molars and the significant different expansion of the upper dental arch at the canine level does not significantly influence the canine angulation following early treatment therapy.

Non-Extraction Treatment of a Skeletal Class II Adult Patient with Severe Crowding Using Temporary Skeletal Anchorage Devices

In skeletal Class II patients with crowding, decision of extraction is a critical step for treatment planning. Recently, non-extraction treatment has been increased in accordance with advancement of orthodontic devices, widespread use of temporary skeletal anchorage devices (TSADs), and application of appropriate biomechanics. Resolution of crowding can be achieved through interproximal reduction, total distalization, expansion of the dental arches and mandibular incisors proclination. Especially arch form development was observed in arch width of canine and premolar areas after treatment. For treatment of Class II patients with severe crowding, strategic use of arch form development and total distalization can extend the scope of non-extraction treatment with a combination of passive self-ligating brackets, wide archwires and TSADs.

Cervical laminoplasty: indication, technique, complications.

Cervical laminoplasty is a non-fusion, decompression procedure for cervical spondylotic myelopathy (CSM). It is most commonly indicated for patients with multilevel stenosis who have preserved sagittal alignment and minimal to no axial neck pain related to spondylosis. Expansion of the laminar arch can allow for direct and indirect decompression of the spinal canal. Relative contraindications include those patients with significant preoperative neck pain, kyphotic alignment and substantial instability. Potential advantages over laminectomy and fusion include avoiding fusion-related complications, and the preservation of motion. Important technical considerations include meticulous extensor muscle management, with special attention being given to preserving the soft tissue attachments to C2. In the properly selected patient, outcomes are comparable, and in some studies superior, to other operations for CSM.

A multicenter, prospective, randomized trial of pain and discomfort during maxillary expansion: Leaf expander versus hyrax expander.

Pain suffered by the young patient is the most frequent symptom during orthodontic treatment and is the one that most frightens children and causes worry in their families. To investigate pain perception and function impairment during the first week of activation of two palatal expansion screws. A total of 101 subjects were randomly divided into two groups: RME group included patients treated with the standard hyrax expansion screw and LEAF group included patients treated with Leaf Expander appliance. Pain intensity was assessed via the Wong-Baker scale. A questionnaire on oral function impairments was also compiled by the patients. The Pain Scale analysis showed that patients in the RME group suffered from a significantly higher level of pain than those in the LEAF group (88.6% vs 25%, P<.01). RME group showed highest pain indexes from day 1 to day 4 (51.4% RME vs 9.7% LEAF suffered at least once from strong pain in the first 4days, P<.01). Furthermore, oral functions were similarly affected in both groups. Pain reported during maxillary arch expansion is influenced by clinical activation protocol and by the screw type. Patients treated with Leaf Expander reported significantly lower pain level in the first 7days of treatment.

Three-Dimensional Evaluation of Change in Maxillary Alveolar Arch after Expansion in Unilateral Cleft Lip and Palate Patients

Narrowing of the maxillary dental arch is a major cause of occlusal abnormalities in cleft lip and palate patients. Although the dental arch may be expanded in such cases, relapse will often occur during the subsequent retention period. In this study, the stability of expansion of the maxillary arch was investigated by examining 3-dimensional change in the maxillary arch during the treatment and post-retention periods. Three-dimensional measurements was performed on maxillary plaster models obtained from 8 unilateral cleft lip and palate patients (mean age, 12.5 years) who had undergone maxillary arch expansion using an edgewise appliance and quad helix (CLP group). The controls consisted of 8 unilateral cleft lip and alveolus patients (mean age, 12.9 years). Measurements were made during the pretreatment, post-treatment, and post-retention periods. In the CLP group, horizontal relapse was observed in the alveolar and dental arches between the second premolars, together with vertical relapse on the cleft side of the central incisor, lateral incisor, and canine. The sites where relapse occurred demonstrated decreased growth before orthodontic treatment. A correlation was observed between the extents of expansion and relapse. These findings suggest that excessive horizontal or vertical tooth movement in areas showing developmental failure should be avoided in order to increase stability after orthodontic treatment.

Surgically Assisted Rapid Palatal Expansion to Correct Maxillary Transverse Deficiency.

Background:Transverse maxillomandibular discrepancies are widespread. Treatment is comprised of orthodontic expansion in patients younger than 15 years or by surgically assisted rapid palatal expansion (SARPE) in skeletally mature patients where the possibility of successful orthodontic maxillary expansion decreases as sutures close and resistance to mechanical forces increases.Aim:To present our experience of treating transverse maxillary deficiency using a unique L-shaped osteotomy and to demonstrate stable results.Patients and Methods:32 patients aged between 19 and 54 years exhibiting transverse maxillary deficiency. L-shaped osteotomy was performed laterally from the pterygoid plate posteriorly to above the roots of the second incisive anteriorly continuing with a vertical osteotomy between the lateral incisive and canine teeth toward the horizontal osteotomy. In 18 patients with dysgnathia, bimaxillary surgery was performed one year following the SARPE procedure.Results:Mean transverse maxillary expansion of 6.2mm at the canine incisal and 6.4mm at the first molar occlusal regions were obtained. One year postoperatively results were relatively stable, 5.8mm and 6.2mm respectively. The SARPE procedure resulted in overcoming the maxillary buttress resistance, expansion of the anterior dental arch and bilateral distraction creating bone on both sides of the premaxilla contributing to better alignment of the anterior teeth and superior stability.Conclusions:We conclude that SARPE is an effective and stable method for addressing severe maxillary transverse discrepancy in adults while the unique osteotomy performed allowed for maintaining proper position of the premaxilla and maxillary midline and allowing for division of the newly created bone bilaterally thus resulting in a more stable outcome.

Bimaxillary transverse constriction in adults: Short-term follow-up of non-surgical arch expansion.

Concurrent maxillary and mandibular expansion is a treatment option for patients with maxillary and mandibular transverse constriction. These patients do not present with crossbite but require expansion due to narrow arches and associated crowding, dark buccal corridors and decreased anterior arch contour. The objective of the study is to first establish Bimaxillary Transverse Constriction as an under-recognized malocclusion and second to evaluate whether in adults the maxillary and mandibular arches can be successfully and safely expanded. Pre- and post-treatment study models and lateral cephalograms of 31 adults with Bimaxillary Transverse Constriction expanded non-surgically were analysed. Thirty adult orthodontic patients who did not require expansion served as a control. Expanders were turned no more frequently than every other day in the maxilla and every third day in the mandible. Measurements in both arches made on OrthoCAD models were transarch widths, molar and premolar axial angulation, clinical crown height of posterior teeth and cuspids, and mandibular divergence. Retrospective comparison of the 2 groups used independent Student's t tests for mean differences between groups. At pre-treatment, the expansion group demonstrated significant transverse constriction compared with the control. Increased widths were achieved in the expansion group (4mm in the maxilla and 2.5mm in the mandible), while the control group was unchanged. The mandibular plane was unchanged. There was no buccal attachment loss. Non-surgical expansion in the maxilla and mandible is a viable treatment option for adult patients with Bimaxillary Transverse Constriction.

Rapid Arch Expansion in Cleft Lip and Palate Children: Comparison Between Fan-Shaped Expander and Hyrax-Type Expander by Using Cone Beam Computed Tomography

Purpose: The aim of the current study was to evaluate the skeletal and dentoalveolar effects of rapid palatal expansion (RPE) in children with cleft lip and palate (CLP), ages 8 to 12 years treated with 2 expanders. Methods: Twenty Egyptian children with complete bilateral CLP exhibiting maxillary transverse deficiency were divided randomly into 2 groups according to the appliance used for expansion: (A) fan expander group. (B) hyrax expander group. Cone-beam computed tomography (CBCT) images were taken before and immediately after expansion procedure. Results: There was non-significant vertical movement of the maxilla for the 2 groups. On the transverse plane, there was more anterior expansion and posterior restriction for the fan group. However, the hyrax group showed significant posterior as well as anterior expansion. Both groups showed significant tipping between both sides posteriorly and anteriorly. Mandibular expansion was non-significant. Conclusion: Fan expander showed better results for children with cleft palate requiring anterior expansion only. Hyrax expander is better used for cases seeking for posterior and anterior expansion.