Conventional Expansion Research Articles

Comparison of the dento-skeletal effects produced by Leaf expander versus rapid maxillary expander in prepubertal patients: a two-center randomized controlled trial.

This study aimed to compare the skeletal and dentoalveolar effects produced by slow maxillary expansion (SME) with the Leaf expander versus the conventional rapid maxillary expansion (RME) on digital dental casts, lateral and postero-anterior cephalometric radiographs. This is a superiority, two-center, two arms parallel balanced randomization trial. Patients in the mixed dentition were included with a transverse interarch discrepancy of at least 3 mm. An expansion screw using moderate continuous forces (Leaf group) was compared to a conventional RME screw (RME group). The primary response variable was the difference in maxillary intermolar width (U6-U6) measured at baseline (T0) and one-year follow-up (T1) on the digital dental casts. Other dento-skeletal variables were also measured on digital dental casts and cephalograms. Computer-generated block randomization was used with allocation concealed in sequentially numbered opaque sealed envelopes. The examiner was blinded on the type of expander used. Linear models were used for statistical analysis. Twenty-eight patients in the Leaf group and 28 patients in the RME group were randomized and included in the study. There were no dropouts. U6-U6 did not show a statistically significant difference between the two groups (-0.4 mm in favor of the RME group, 95% CI from -1.2 to 0.5, P = 0.365). As for the other secondary variables no statistically significant differences were found between the two groups except maxillary intercanine width (U3-U3, -0.9 mm in favor of the RME group, 95%CI from -1.5 to -0.3, P = 0.005) and maxillary skeletal width (Mx-Mx, -1.4 mm in favor of the RME group, 95%CI from -2.4 to -0.3, P = 0.013). No significant differences between the RME and Leaf groups were detected for any of the analyzed dento-skeletal variables except the T1-T0 differences in U3-U3 and Mx-Mx that were significantly greater in the RME group. The study was registered in the ISRCTN register on 08/11/2016 with the number ISRCTN18263886. No funding or conflict of interest to be declared.

MODERN PERSPECTIVES ON RAPID PALATAL EXPANSION

Maxillary deficiency in the transverse dimension is a common problem in children. The conventional management of such malocclusion is with conventional rapid maxillary expansion. The beneficial effects of such an orthodontic therapy are explained in detail in the literature. But there are also negative effects of conventional rapid maxillary expansion. Thus, the improvements in the methods of expansion has led to discovery of miniscrew assisted rapid palatal expansion. The miniscrew assisted rapid palatal expansion are supported by mini implants and thus enable better skeletal expansion of maxilla. This article will discuss the favourable effects, negative effects, and clinical uses of conventional and miniscrew assisted rapid palatal expansion.

Optimization of culture conditions for human bone marrow-derived mesenchymal stromal cell expansion in macrocarrier-based Tide Motion system.

With high cell doses required for mesenchymal stromal cell (MSC) clinical trials, there is a need to upgrade technologies that facilitate efficient scale up of MSCs for cell therapy. Conventional expansion with 2D culture vessels becomes the bottleneck when large cell dosages are required. Tide Motion bioreactors offer a robust, scalable platform using BioNOC II macrocarriers developed for the production of adherent cells. We evaluated the growth and expansion of bone marrow-derived MSCs (BM-MSCs) on the macrocarrier-based culture system by optimizing key parameters such as cell seeding densities, culturing conditions, and harvesting procedures to achieve optimal cell growth. BM-MSCs expanded in conventional 2D adherent cultures were seeded into BioNOC II macrocarriers and grown in serum-containing or serum-free medium. BM-MSCs attained a maximum cell density of 0.49 ± 0.07×106 cells/carrier after 12 days of culture in BioNOC II macrocarriers with cell viability > 86% while retaining MSC specific characteristics such as surface marker expression, tri-lineage differentiation potential, immunosuppressive properties, and potency. These results reveal the feasibility of BM-MSC expansion in the scalable macrocarrier-based Tide Motion system both under serum and serum-free conditions and represent an important step for the large-scale production system of BM-MSC based cellular therapies.

Feasibility study and in-depth performance assessment of needle valve using as expansion device in refrigeration system

The needle valve (NEV) has high potential for further using as the automatic expansion device in the refrigeration system. However, the experimental proof is required for further developing the automatic controller for operation. This paper proposes the feasibility study and performance map of the needle valve (NEV) using as the expansion device in a small vapour compression refrigerator (VCR). The relevant parameters produced by NEV are compared with those using capillary tube (CT) and thermostatic expansion valve (TEV) which are the conventional device. The system COP, superheated degree at evaporator outlet (SHDevap-out), subcooled degree at condenser outlet (SCDcon-out), mass flow rate, volumetric refrigeation capacity, compressor's specific work and refrigerant quality are considered for comparisons. Additionally, the economic assessment of using NEV compared with the other two devices is proposed. It is found that COP produced by NEV are similar to TEV which is better than CT. The ecomnomic assessment indicates that the NEV produces similar useful cooling energy per unit cost to that using TEV which is higher than CT. Overall results indicate that the NEV can efficiently be used as the expansion device in VCR which is alternative to the conventional expansion devices.

Adipose tissue-derived stem cells: a comparative review on isolation, culture, and differentiation methods.

Adipose tissue-derived stem cells (ADSCs) are an available source of mesenchymal stem cells with the appropriate capacity to in vitro survive, propagate, and differentiate into cells from three lineages of ectoderm, mesoderm, and endoderm. The biological features of ADSCs depend on the donor physiology and health status, isolation procedure, culture conditions, and differentiation protocols used. Adipose tissue samples are provided by surgery and lipoaspiration-based methods and subjected to various mechanical and chemical digestion techniques to finally generate a heterogeneous mixture named stromal vascular fraction (SVF). ADSCs are purified through varied cell populations that exist within SVF and cultured under standard conditions to give rise to a highly rich resource of stem cells directly applied in the clinic or differentiated into a wide range of cells. The development and optimization of conventional isolation, expansion, and differentiation methods seem noteworthy to preserve the desirable biological functions of ADSCs in pre-clinical and clinical investigations.

An agent-based Stackelberg framework for joint expansion planning of privately Owned regional energy systems and sub-transmission grid

Traditionally, a regional electric company (REC) should supply electricity demand of consumers at sub-transmission level in special geographic areas. As a promising alternative for traditional centralized planning, in this paper, a Stackelberg game approach is employed to solve the investment and operational expansion planning problems in the presence of privately owned Regional Energy Systems (RGESs) and multi-agent systems are used to ease the participation of private ownerships in planning model by preventing agents to disclose their private properties. The RGES's and the REC's agents are the active players of the proposed method and in the form of a semi-decentralized framework, the information exchange among them is fully decentralized. Also, an Independent Coordinating Agent (ICA) is centrally responsible for Stackelberg Nash equilibrium point extraction. Further, a bi-stage Stackelberg game approach is proposed for coupled expansion planning program of Sub-transmission network and privately owned RGESs. To validate the feasibility and efficacy of the suggested model, a modified electric sub-transmission system (located in Guilan Province, Islamic Republic of Iran) is employed as a realistic test case system for simulations. And, the obtained results of simulations by the proposed method are compared with conventional expansion planning of sub-transmission systems.

Evaluation of the Relationship Between Midpalatal Suture Maturation Indicators as Predictors for Surgically-Assisted and Conventional Rapid Maxillary Expansion.

Rapid maxillary expansion (RME) is an effective orthopedic procedure to correct maxillary transversal deficiency in young patients. In cases of sutural closure, surgically assisted RME is used to reduce the resistance to sutural disjunction. Foundation of a diagnostic relationship between maturation indices and the expected skeletal response to expansion can enable clinicians to identify the need for surgically assisted RME prospectively. The primary aim of this study was to assess the correlation between the amount of achieved skeletal expansion with midpalatal suture density on computed tomography images, and the secondary aim was to assess the correlation between the amount of achieved skeletal expansion with the recently suggested midpalatal suture maturation indicators: cervical vertebral maturation (CVS), midpalatal suture maturation stage (MPSM) and midpalatal suture density ratio. Forty Digital Imaging and Communications in Medicine data from the archived computed tomography scans of 20 patients (mean age: 15.55 years) before RME (T1) and after 3-month retention period (T2) were analyzed. The tested maturity indicators did not show statistically significant correlation between the skeletal effect proportions. However, clinically and radiologically effective RME was seen in MPSMs A, B, and C and also cervical vertebra stages CVS5 and CVS6. More research is needed to determine a diagnostic predictor for the skeletal effects of maxillary expansion treatment modalities.

Ion channel engineering using protein trans-splicing.

Conventional site-directed mutagenesis and genetic code expansion approaches have been instrumental in providing detailed functional and pharmacological insight into membrane proteins such as ion channels. Recently, this has increasingly been complemented by semi-synthetic strategies, in which part of the protein is generated synthetically. This means a vast range of chemical modifications, including non-canonical amino acids (ncAA), backbone modifications, chemical handles, fluorescent or spectroscopic labels and any combination of these can be incorporated. Among these approaches, protein trans-splicing (PTS) is particularly promising for protein reconstitution in live cells. It relies on one or more split inteins, which can spontaneously and covalently link flanking peptide or protein sequences. Here, we describe the use of PTS and its variant tandem PTS (tPTS) in semi-synthesis of ion channels in Xenopus laevis oocytes to incorporate ncAAs, post-translational modifications or metabolically stable mimics thereof. This strategy has the potential to expand the type and number of modifications in ion channel research.

Combinatorics for calculating expectation values of functions in systems with evolution governed by stochastic differential equations

Stochastic differential equations are widely used in various fields; in particular, the usefulness of duality relations has been demonstrated in some models such as population models and Brownian momentum processes. In this study, a discussion based on combinatorics is made and applied to calculate the expectation values of functions in systems in which evolution is governed by stochastic differential equations. Starting with the duality theory of stochastic processes, some modifications to the interpretation and usage of time-ordering operators naturally lead to discussions on combinatorics. For demonstration, the first and second moments of the Ornstein–Uhlenbeck process are re-derived from the discussion on combinatorics. Furthermore, two numerical methods for practical applications are proposed. One method is based on a conventional exponential expansion and the Padé approximation. The other uses a resolvent of a time-evolution operator, along with the application of the Aitken series acceleration method. Both methods yield reasonable approximations. Particularly, the resolvent and Aitken acceleration show satisfactory results. These findings will provide a new way of calculating expectations numerically and directly without using time-discretization.

Reversible Data Hiding Based on Adaptive Multiple Histograms Modification

Pixel value ordering prediction has been verified as an effective mechanism to exploit image redundancy for reversible data hiding (RDH) and numerous extensions have been devised. However, their performance is still unsatisfactory since the error modification is generally fixed and independent of image content. In this paper, a new RDH scheme is proposed by incorporating pixel distance to realize adaptive multiple histograms modification (AMHM). During exploiting the correlation between the largest/smallest pixel and any other one in the scope of pixel block, we propose to process every two correlated pixels successively following the ascending order of their distance. Specifically, the generated errors with a given distance are collected and verified. If they are all shiftable errors, the follow-up errors would be collected into the next sub-histogram. In this way, a histogram sequence is adaptively generated such that different modification mechanisms can be taken for different sub-histograms to achieve adaptive embedding. Finally, AMHM for conventional prediction-error expansion (PEE) and AMHM for 2D PEE have been both realized in this paper. Experimental results show that AMHM is of great significance to better exploit pixel correlation and the proposed scheme outperforms a series of the latest schemes.

Novel Unilateral Dental Expander Appliance (UDEX): A Compound Innovative Materials

True unilateral posterior crossbite in adults is a challenging malocclusion to treat, especially when we need to correct cross-arch segments with unwanted effects on non-cross segments. Conventional expansion methods are expected to have some shortcomings;the Unilateral dental expander appliance used to restore unilateral cross bite dental arch is an uncommon appliance;for this, a designed new device is needed. This paper aimed to invite a new unilateral dental expander appliance (UDEX) to treat unilateral dental posterior crossbite in adults using available dental material, easy to use and handle, well tolerated by the patient, and biocompatible with oral structure. It could find that in all dental markets and dental clinics-an eighteen-year-old female with bilateral crossbite and upper and lower dental arch crowding. During active orthodontic treatment, a quad-helix expander had broken from one side at soldering between band and wire attachment. The patient did not show up to the clinic for a while due to COVID 19 pandemic lockdown, leading to a true unilateral crossbite at the dental arch's upper left side, especially at the molar premolars area. This unilateral cross bite was treated using a new specially designed expanded appliance as a unilateral posterior cross bite dental maxillary expander. As a result of this study, orthodontic treatment was finished within (15) months, much less than expected. We obtained Class I molar and canine relationships with uncrossed dental arches in both upper arch sides, proper overbite and overjet with well-leveled and aligned teeth as it confirmed by clinical examination and radiographic images (OPG (Orthopantomogram) and cephalometric radiograph (WebCeph analysis digitalized computer program). Conclude from that, the newly designed unilateral dental expander (UDEX) is proven to be useful for treating real unilateral posterior crossbites as single molar or premolar tooth andmultiple joint unilateral crossed posterior teeth. Also, it could easily modify it for future unilateral crossed purposes. This appliance was fabricated using readily available dental material, well tolerated by patients, and reduced the need for excessive patient compliance. An orthodontist could fabricate devices, or cautious laboratory work is required;it can rapidly achieve favorable results. © 2021 Tech Science Press. All rights reserved.

Multipole expansion of integral powers of cosine theta

Legendre polynomials form the basis for multipole expansion of spatially varying functions. The technique allows for decomposition of the function into two separate parts with one depending on the radial coordinates only and the other depending on the angular variables. In this work, the angular function cos ^k theta is expanded in the Legendre polynomial basis and the algorithm for determining the corresponding coefficients of the Legendre polynomials is generated. This expansion together with the algorithm can be generalized to any case in which a dot product of any two vectors appears. Two alternative multipole expansions for the electron–electron Coulomb repulsion term are obtained. It is shown that the conventional multipole expansion of the Coulomb repulsion term is a special case for one of the expansions generated in this work.

Application and Comprehensive Analysis of Neighbor Approximated Information Theoretic Configurational Entropy Methods to Protein-Ligand Binding Cases.

The binding entropy is an important thermodynamic quantity which has numerous applications in studies of the biophysical process, and configurational entropy is often one of the major contributors in it. Therefore, its accurate estimation is important, though it is challenging mostly due to sampling limitations, anharmonicity, and multimodality of atomic fluctuations. The present work reports a Neighbor Approximated Maximum Information Spanning Tree (A-MIST) method for conformational entropy and presents its performance and computational advantage over conventional Mutual Information Expansion (MIE) and Maximum Information Spanning Tree (MIST) for two protein-ligand binding cases: indirubin-5-sulfonate to Plasmodium falciparum Protein Kinase 5 (PfPK5) and P. falciparum RON2-peptide to P. falciparum Apical Membrane Antigen 1 (PfAMA1). Important structural regions considering binding configurational entropy are identified, and physical origins for such are discussed. A thorough performance evaluation is done of a set of four entropy estimators (Maximum Likelihood (ML), Miller-Madow (MM), Chao-Shen (CS), and James and Stein shrinkage (JS)) with known varying degrees of sensitivity of the entropy estimate on the extent of sampling, each with two schemes for discretization of fluctuation data of Degrees of Freedom (DFs) to estimate Probability Density Functions (PDFs). Our comprehensive evaluation of influences of variations of parameters shows Neighbor Approximated MIE (A-MIE) outperforms MIE in terms of convergence and computational efficiency. In the case of A-MIE/MIE, results are sensitive to the choice of root atoms, graph search algorithm used for the Bond-Angle-Torsion (BAT) conversion, and entropy estimator, while A-MIST/MIST are not. A-MIST yields binding entropy within 0.5 kcal/mol of MIST with only 20-30% computation. Moreover, all these methods have been implemented in an OpenMP/MPI hybrid parallel C++11 code, and also a python package for data preprocessing and entropy contribution analysis is developed and made available. A comparative analysis of features of current implementation and existing tools is also presented.

Secondary vault reconstruction after open or minimal invasive correction for unisutural, multisutural or syndromic craniosynostosis: A cohort study on the impact of diagnosis and type of initial surgical technique

The aim of this study is to identify if certain types of craniosynostosis and/or surgical procedures are more likely to require a secondary intracranial procedure because of insufficient correction of skull shape or raised ICP after initial surgery. All consecutive cases with craniosynostosis that were operated at our center between January 2010 and January 2019 were included and the number of secondary operations of the vault were determined, as well as diagnosis, the indication and type and timing of initial surgery. Monobloc and facial bipartition procedures were excluded. Over a nine year period, 790 vault corrections were performed in 780 patients of which 38 procedures were reoperations in 35 patient because of raised intracranial pressure or an insufficient esthetic result of the skull shape. Particularly patients with a multisutural or syndromic craniosynostosis are represented in this group, as well as three surgical procedures: 1. biparietal outfracturing for sagittal synostosis; 2. endoscopic stripcraniectomy with helmet therapy for unicoronal, multisutural or syndromic craniosynostosis; 3. conventional occipital expansion for syndromic craniosynostosis. The risk of a second intracranial correction for insufficient outcome of skull shape or for raised ICP is related to type of synostosis and type of initial surgical technique. Particularly multisutural and syndromic craniosynostosis are more likely to require repeat surgery for these indications. Concerning initial technique, biparietal outfracturing does not correct sagittal synostosis sufficiently, stripcraniectomy with helmet therapy appears to undercorrect unicoronal, multisutural and syndromic synostosis, and conventional occipital expansion for multisutural and syndromic synostosis has poorer outcome than occipital expansion with distraction.

Blossom smart expander technology for tissue expander-based breast reconstruction facilitates shorter duration to full expansion: A pilot study.

BackgroundThis study evaluated the Blossom system, an innovative self-filling, rate-controlled, pressure-responsive saline tissue expander (TE) system. We investigated the feasibility of utilizing this technology to facilitate implant-based and combined flap with implant-based breast reconstruction in comparison to conventional tissue expansion.MethodsIn this prospective, single-center, single-surgeon pilot study, participants underwent either implant-based breast reconstruction or a combination of autologous flap and implantbased breast reconstruction. Outcome measures included time to full expansion, complications, total expansion volume, and pain scores.ResultsFourteen patients (TEs; n=22), were included in this study. The mean time to full expansion was 13.4 days (standard error of the mean [SEM], 1.3 days) in the combination group and 11.7 days (SEM, 1.4 days) in the implant group (P=0.78). The overall major complication rate was 4.5% (n=1). No statistically significant differences were found in the complication rate between the combination group and the implant group. The maximum patient-reported pain scores during the expansion process were low, but were significantly higher in the combination group (mean, 2.00±0.09) than in the implant group (mean, 0.29±0.25; P=0.005).ConclusionsThe reported average duration for conventional subcutaneous TE expansion is 79.4 days, but this pilot study using the Blossom system achieved an average expansion duration of less than 14 days in both groups. The Blossom system may accommodate single-stage breast reconstruction. The overall complication rate of this study was 4.5%, which is promising compared to the reported complication rates of two-stage breast reconstruction with TEs (20%–45%).

What is the dosimetric impact of isotropic vs anisotropic safety margins for delineation of the clinical target volume in breast brachytherapy?

PurposeThe purpose of the study was to report dosimetric differences for breast brachytherapy plans optimized for clinical target volume (CTV) generated using conventional isotropic expansion of tumor bed volume (TBV) and Groupe Européen de Curiethérapie–European Society for Radiotherapy and Oncology (GEC-ESTRO) recommendations to expand the TBV anisotropically to achieve a total safety margin of 2 cm (resection margin size + added safety margin). MethodsInstitutional records of 100 patients who underwent accelerated partial breast irradiation using multicatheter interstitial brachytherapy from May 2015 to March 2020 were reviewed retrospectively. Two sets of CT-based plans were made, one with 1-cm isotropic margins around the tumor bed (CTV_ISO) and the other with anisotropic margins (CTV_GEC). Plans were evaluated and compared using the American Brachytherapy Society and GEC-ESTRO guidelines. ResultsThe median TBV was 36.97 cc. The median margin widths were as follows: anterior 1.2, posterior 1.0, superior 1.0, inferior 0.9, medial 1.2, and lateral 1.2 cm. The mean tumor bed coverage index was 0.94; 0.93 [p.066], the CTV coverage index 0.86; 0.84 [p 0.001], the dose homogeneity index (DHI) 0.77; 0.75 [p < 0.001] and the conformity index 0.66; 0.64 [p < 0.001] in CTV_ISO and CTV_GEC plans, respectively. In smaller volume implants (TBV< 35 cc), the DHI was 0.76; 0.75 [p 0.008] and the conformity index was 0.66; 0.62 [p < 0.001], whereas in larger volumes >35 cc, the CTV coverage index was 0.86; 0.84 [p 0.003] and the DHI 0.78; 0.76 [p 0.001] in CTV_ISO and CTV_GEC plans, respectively. ConclusionsIn this cohort of patients who underwent accelerated partial breast irradiation, plans with anisotropic margins had lower conformity, the impact of which was predominantly seen in smaller implants. Rest of the dosimetric constraints were achieved in both the plans as per the American Brachytherapy Society and GEC-ESTRO guidelines.

Hierarchical duality-based planning of transmission networks coordinating active distribution network operation

The active distribution network becomes more stochastic due to high penetration of renewable energy sources, and it can transfer surplus power for transmission needs. If the distribution optimization problem collaborates with the conventional transmission expansion formulation, the coordination can also postpone the investment decisions for the transmission network, not only optimize the operation of the entire power system. In view of these, this paper presents a bi-level hierarchy transmission expansion formulation coordinating distribution networks. The upper level of the hierarchical decision-making framework corresponds to the objective and constraints of the transmission network, whereas the lower level relates to the distribution perspective. An approximation technique is used to make the constraints of the distribution network linear, which guarantees that the proposed bi-level program can be solved using the duality-based approach. Numerical tests carried out on two transmission-distribution integration networks demonstrate the effectiveness and high performance of the proposed hierarchical duality-based model to accommodate renewable energy. In addition, sensitivities of the transmission investment decisions are analysed in terms of externalities in transmission and distribution networks. Compared with conventional isolated optimization, results show that the total costs of T24D9 and T38D3 by the proposed hierarchical coordinated optimization can respectively reduce by 34.38 M$ and 382.23 M$. So the economic benefits are remarkable, and the proposed optimization is reasonable and valuable.

An advanced control strategy for DC interconnections of distribution systems considering curative system security

The increasing amount of renewable energy infeed into distribution systems has become a challenge for power system operation. Connecting several distribution systems via VSC-based DC-interconnections has been identified to be an effective alternative to conventional grid expansion to relieve the power systems. This paper introduces an advanced control strategy for DC-interconnected distribution systems based on curative system security to increase the maximum utilization of existing assets within security limitations. Furthermore, an approach to coordinate the setpoint determination of a DC-interconnection between two DSO's is introduced in this work.

Energy and environmental investigation of R744 all-in-one configurations for refrigeration and heating/air conditioning needs of a supermarket

Refrigeration systems and heating/air conditioning units used in supermarkets are responsible for a great part of the annual electricity consumption of industrialized countries. Taking also into consideration the direct emissions of carbon dioxide to the environment due to leakage of refrigerants with high Global Warming Potential that are employed today for such applications, a step towards more environmentally friendly and less energy-consuming solutions should be made. In the current research, different topologies of an all-in-one R744 transcritical unit providing refrigeration, heating and air conditioning to a real Greek supermarket store (METRO S.A.) in Athens are studied, using the softwares Engineering Equation Solver and EnergyPlus. The different configurations include a state-of-the-art R744 system with parallel compression and multi-ejector block, the same system with the addition of a subcooling heat exchanger that utilizes available geothermal water, as well as the last described unit with the integration of adiabatic cooling configuration on the gas cooler. These solutions are investigated in terms of energy efficiency and environmental impact (total equivalent warming impact) and they are compared to an indirect arrangement employing R744 and R290, to conventional direct expansion solutions (with R448A or R404A) and to a heat pump employing R410A that covers the heating and air conditioning demands of the supermarket. The comparative energy analysis was separated into the refrigeration part, the heating and air conditioning part and the sum of them. The results indicated that for the climate of the store’s location, the case including the subcooler and adiabatic cooling configuration, the case with only the subcooler and the case with neither the subcooler nor the adiabatic cooling configuration consume annually 20.9%, 17.6% and 8.7% less energy respectively than the combination of a refrigeration unit with R448A and a heat pump with R410A for the heating/cooling needs.

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.