Expansion Screw 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.

A Simple Screw-Type Wrap-Around Retainer

Retainers are used after orthodontic correction to maintain the teeth in the new position while allowing remodeling of the surrounding tissue. Begg’s wrap-around retainers are the most commonly used retainers after orthodontic correction for providing stability to the achieved orthodontic correction. It is not always possible for the patient to visit the orthodontist periodically, especially during situations like pandemics. This new design of Begg’sretainer has been modified with the addition of expansion screws for self-activation, thus reducing the need for the patient to visit the orthodontist for activation of the retainer.

Influence of the hyrax expander screw position on displacement and stress distribution in teeth: A study with finite elements

This study aimed to simulate the different positions of the hyrax appliance expander screw and evaluate tooth displacement and the stress distribution standard on the periodontal ligament using the finite element method. Part of the maxilla with anchorage teeth, periodontal ligament, midpalatal suture, and the hyrax appliance was modeled, and finite element method models were created to simulate 6 different screw positions. There were 2 vertical positions at distances of 20mm and 15mm from the occlusal plane. Another position was anteroposterior, the center of the screw placed between and equidistant from the mesial face of the first molar and the distal face of the first premolar, aligned to the center of the crown of the first molar, with the anterior edge of the screw aligned to the distal face of the first molar. A 1mm activation of the expander screw was simulated. The displacement (total, vertical, and buccolingual) and the stress distribution on the periodontal ligament of supporting teeth in each model were registered. The model simulating the expander screw in a more occlusal and anterior position presented higher displacement values and higher stress concentration, followed by the model with the screw in a more posterior but same vertical position. With the exception of the first premolar, the teeth presented cervical-apical displacement in the vestibular face and apical-cervical displacement in palatal faces. This displacement is compatible with the vestibular inclination associated with the activation of the expander screw. The first premolar presented an atypical tendency for the mesial and lingual displacement of the vestibular surface and counterclockwise rotation. The supporting teeth presented a tendency for vestibular crown displacement and lingual root displacement associated with compression areas in the vestibular-cervical region and tensile strength in the linguoapical region. Placing the expander screw in a more occlusal and anterior position generated more mechanical stress transfer, resulting in greater dental displacement.

A dynamic stability design strategy for lithium metal solid state batteries

A solid-state electrolyte is expected to suppress lithium (Li) dendrite penetration with high mechanical strength1-4. However, in practice it still remains challenging to realise a lithium metal anode for batteries, because micrometre- or submicrometre-sized cracks in ceramic pellets can frequently be generated during battery assembly or long-time cycling3,5. Once cracks form, lithium dendrite penetration is inevitable6,7. Here we describe a solid-state battery design with a hierarchy of interface stabilities (to lithium metal responses), to achieve an ultrahigh current density with no lithium dendrite penetration. Our multilayer design has the structure of a less-stable electrolyte sandwiched between more-stable solid electrolytes, which prevents any lithium dendrite growth through well localized decompositions in the less stable electrolyte layer. A mechanism analogous to the expansion screw effect is proposed, whereby any cracks are filled by dynamically generated decompositions that are also well constrained, probably by the 'anchoring' effect the decompositions induce. The cycling performance of the lithium metal anode paired with a LiNi0.8Mn0.1Co0.1O2 cathode is very stable, with an 82 per cent capacity retention after 10,000 cycles at a20Crate (8.6milliamps per centimetre squared) and 81.3 per cent capacity retention after 2,000 cycles ata 1.5Crate (0.64milliamps per centimetre squared). Our design also enables a specific power of 110.6 kilowatts per kilogram and specific energy up to 631.1 watt hours per kilogram at the micrometre-sized cathode material level.

A Staged Expansion Screw Protocol to Retract the Premaxilla In BCLP Infants with Delayed Nasoalveolar Molding.

Currently, the treatment protocol for cleft palate at several centers around the world involves primary lip repair around 3-4 months of age, using presurgical nasoalveolar molding, which is done soon after birth. Unfortunately, in cases where treatment is delayed, the potential for repositioning the nasoalveolar apparatus is severely limited. The purpose of this paper is to illustrate a novel use of an expansion screw appliance to aid in the faster and more efficient active molding of the premaxillary and lateral maxillary segments in infants for whom the start of PNAM therapy is delayed, without the side effects commonly seen with pin-retained active molding appliances.

Evaluation of Alt-RAMEC With Facemask in Patients With Unilateral Cleft lip and Palate (UCLP) Using Cone Beam Computed Tomography (CBCT) and Finite Element Modeling-A Clinical Prospective Study.

Evaluate the effects of alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocol on patients with unilateral cleft lip and palate (UCLP) along with maxillary protraction using cone beam computed tomography (CBCT) records and a finite element modeling (FEM) model. Twenty-five patients (aged 9-13 years) with UCLP having a GOSLON score 3 were selected for this prospective single-arm cohort study after obtaining necessary informed consent. A 9-week Alt-RAMEC protocol using a custom-made fan-shaped expansion screw was initiated, which was followed by 6-month facemask wear. Pre (T1) and posttreatment (T2) records including CBCT were taken and were evaluated for treatment changes in all 3 dimensions using paired t test. Additionally, a FEM model (ANSYS 15.0) using the Alt-RAMEC protocol was also analyzed for the displacement and stress on various craniofacial structures. Significant forward movement of the maxilla along with clockwise rotation of mandible along with statistically significant increase in lower molar height and upper incisor proclination (P < .05) was observed. CBCT evaluation showed a statistical significant decrease in buccal alveolar bone thickness and increase in molar inclination (P < .05). Finite element modeling analysis highlighted that the maximum displacement occurred at the anterior region with stresses radiating till the anterior nasal spine, zygomatic arch, and sphenoid bone. Alt- RAMEC protocol combined with facemask protraction can lead to significant maxillary advancement, with some transient decrease in buccal bone thickness noted thereby warranting long-term studies to further assess its effect on the dentofacial apparatus.

Evaluation of Initial Stress Distribution and Displacement Pattern of Craniofacial Structures with 3 Different Rapid Maxillary Expansion Appliance Models: A 3-dimensional Finite Element Analysis.

This study aimed to describe the displacement of anatomical structures and the stress distributions caused by the Hyrax, fan-type, and double-hinged expansion screws via the 3-dimensional (3D) finite element method (FEM). The 3D FEM was based on the computed tomography data of a 12-year-old patient with a constricted maxilla. The Hyrax model included 1,800,981 tetrahedral elements with 2,758,217 nodes. The fan-type model included 1,787,558 tetrahedral elements with 2,737,358 nodes. The double-hinged model included 1,777,080 tetrahedral elements with 2,722,771 nodes. The von Mises stress distributions after 0.2 mm of expansion and displacement patterns after 5 mm of expansion were evaluated. The highest stress accumulation was observed in the sutura zygomatico maxillaris area with all 3 appliances. An increase in stress was noted at the pterygomaxillary fissure, the medial and lateral pterygoid process of the sphenoid bone, and the nasal areas. The wedge-shaped skeletal opening was observed with all 3 appliances. In the transverse plane, maximum posterior expansion was achieved with the Hyrax appliance, whereas the maximum anterior expansion was observed with the double-hinged appliance. The maxilla moved inferiorly and anteriorly with all the 3 appliances. The greatest inferior displacement of the maxilla was recorded with the Hyrax appliance, whereas anterior maxillary displacement was the greatest with the double-hinged appliance. All the appliances showed similar stress distributions. The use of double-hinged screw caused a slight anterior displacement of point A. The fan-type and double-hinged appliances were shown to be more effective on anterior maxillary constriction, whereas the Hyrax appliance might be chosen for resolving maxillary posterior constriction.

Perceived pain during rapid maxillary expansion in children with different expanders.

To evaluate and compare the intensity of pain caused by rapid maxillary expansion (RME) with two expanders: Hyrax and Haas type, in growing patients. Thirty-nine patients (23 girls and 16 boys) with an average age of 9.3 years (SD = 1.39 years) were randomized into two groups and treated with Hyrax- and Haas-type expanders. In both groups, initial activation of the expander screw was one full turn on the first day followed by 2/4 of a turn two times a day (morning and night) for 7 days. Inclusion criteria were patients presenting with a posterior crossbite or maxillary atresia between 7 and 12 years old. To evaluate the intensity of pain during the active phase of the treatment, a combination of the Numerical Rating Scale and Wong-Baker Faces Pain Scale was used. Mann-Whitney test was used to compare the two treatment groups. There was significant inverse correlation between days following insertion and pain. During the expansion period, 100% of the children reported some pain. Hyrax expander subjects reported greater pain than those treated with the Haas-type expander only on the first day. The level of pain remained greater in girls throughout treatment. Pain was reported regardless of the type of expander and was higher in the Hyrax group only on the first day of activation.

Predictors of patient compliance during Class II division 1 malocclusion functional orthodontic treatment

To determine factors that could predict Class II/1 malocclusion patient compliance during functional treatment. The sample consisted of 77 subjects (aged 11-13 years; 47% girls) presenting with Class II/1 malocclusion. Inclusion criteria were distal molar relationship, overjet greater than 5 mm, and confirmed pubertal growth spurt. Removable functional appliances (62% Twin Block [TB], 38% Sander Bite Jumping [BJ]) with built-in maxillary expansion screws were used. Follow-up period was 1 year. Patients and parents independently filled out the Child Perception Questionnaire, Parental/Caregiver Perception Questionnaire, and Family Impact Scale to assess emotional and social well-being, oral symptoms, functional limitations, parental emotions, family activities, conflicts, and financial burden as possible predictors of compliance during treatment. Sex, overjet, and appliance type were also analyzed. There were more noncompliant than compliant patients (55% vs 45%). Parental perception of altered emotional well-being of their children was the strongest predictor, increasing compliance odds 3.4 times (95% confidence interval [CI], 1.2-9.4; P = .017). Patients were 3.2 times (95% CI, 1.1-9.3; P = .033) more likely to cooperate with TB compared with BJ appliance. OJ ≥ 8 mm increased compliance odds 3.1 times (95% CI, 1.0-9.4; P = .044). Parental perception of child's emotional well-being alteration, severity of malocclusion, and type of appliance are major predictors of compliance. Psychosocial issues and oral function limitations reported by children and family impact are of negligible influence.

THE EFFECTIVENESS OF ACTIVE MODIFIED PRESURGICAL NASOALVEOLAR APPLIANCE IN ALIGNMENT OF PREMAXILLA OF COMPLETE BILATERAL CLEFT LIP AND PALATE INFANTS

INTRODUCTION: Complete bilateral cleft lip and palate CBCLP is considered the most difficult form of cleft cases nowadays. Nasoalveolar molding enhances the esthetic and functional results of cleft infants. NAM works on the principle of sculpting and molding of the alveolus and adjacent soft tissues.OBJECTIVES: The aim of this study was to assess the efficiency of a presurgical modified screw activated NAM appliance in retruding the premaxilla for CBCLP infants.MATERIALS AND METHODS: Fifteen CBCLP infant were included in the study. Preliminary maxillary impressions were made and the produced casts were scanned to obtain three-dimensional virtual image which was used to plan the design of the appliance. Two-piece acrylic active appliance with reverse expansion screw was used to retrude the premaxilla. The appliance was retained in place using niklel chromium side extension arms and head cap. When the cleft gap was closed to be suitable for surgical repair, primary lip repair was performed. Impressions were made again; the casts were scanned to be converted into 3D models on which linear analysis of the cleft gap was done.RESULTS: The results showed statistically significant decrease in the cleft gap following active alveolar molding.CONCLUSION: Active NAM appliance can effectively retrude and correct the severely rotated and deviated premaxilla providing better esthetic results.

Corrección de mordida cruzada anterior de origen dental y recesión gingival en dentición mixta temprana. Reporte de caso

Introducción: La mordida cruzada anterior ocurre cuando los incisivos superiores ocluyen lingualmente a los inferiores, pudiendo ser de origen dental o esquelético. La corrección temprana de esta maloclusión favorece una correcta relación interincisiva, permitiendo el adecuado crecimiento y desarrollo en sentido sagital del complejo máxilo facial. Reporte del caso: Paciente masculino de 8 años de edad. Se realizó estudio ortodóncico completo siendo el diagnóstico cefalométrico Clase I y dentario de Clase I tipo 3 con retroinclinación de incisivos superiores, casoy mordida cruzada de origen dental. Presentó recesión gingival en encía vestibular de 41 y 31. El tratamiento realizado incluyó aparato removible con placa de levantamiento posterior, tornillo expansor anterior y arco de Eschler. Se realizó seguimiento por 16 meses, obteniendo el descruzamiento de la mordida anterior, conformación de arco e inclinación apropiada del incisivo superior. Conclusiones: El tratamiento de la mordida cruzada anterior de origen dentario puede ser logrado en dentición mixta utilizando mecánicas sencillas.

Effects Of Removable Anterior Expansion Screw on Speech Intelligibility In a Group of Egyptian Children

Abstract Aim : This study was conducted to evaluate the speech disorders that could be reported after insertion of removable anterior expansion screw appliances used for correction of anterior dental crossbite. Materials and Methods: Fifty children with mean age (9.36±0.99 years) and diagnosed to have anterior dental crossbite. The anterior crossbite was planned to be corrected with removable anterior screw and posterior bite plane. Speech evaluation (including: articulation test and speech intelligibility test) was performed ; before appliance insertion , immediately after appliance insertion , one weeh after appliance insertion and finally after one month from appliance insertion . Results : Before appliance insertion, all sounds were intact for the majority of the cases 42(84%). Immediately after insertion, all the cases had difficulty in producing /s/, /s. /, /z/ sounds (100%). After one week of insertion, majority of the cases 30(60%) still had difficulty in producing the same sounds. While, After one month of insertion, most of the cases 40(80%) had no problem in producing different sounds . Conclusion : The speech performance while using removable anterior expansion screw for was worst immediately after placement of the appliance and 1 week respectively and improved after one month of appliance insertion.

Management of Unilateral Multiple Impacted Molars- An Interdisciplinary Approach of a Rare Clinical Case

Impaction of first, second and third molars at once comprise a rare clinical scenario with diverse therapeutic approaches and possess a great challenge for the dentist. Early detection of the eruption disturbances helps to manage and produce optimal outcomes. Here, the authors reported a case of 17-year-old male patient who reported with the chief complaint of pain in his lower left back tooth region with difficulty in mouth opening and chewing that revealed impacted mandibular left first, second and third molar on radiographic investigation. A proper decision making is required to satisfy the patient and also get an effective result. As the patient had severe pain in the left side of the jaw near the angle of the mandible, surgical removal of the impacted molars was planned and performed using extra oral submandibular approach. Following the removal of the teeth, implants were placed in the extracted site supported by bone graft material and fixed orthodontic appliance therapy was carried out to correct the supra- erupted upper molars on the left side and arch expansion screw with upper Hawley’s appliance was given to expand the maxillary arch to aid in appropriate occlusion. Restoration of the implant was done after one year of orthodontic treatment using ceramic crowns. The combined surgical, orthodontic and periodontal interdisciplinary approach helped the patient to gain proper occlusion and satisfactory masticatory function.

Resident Commentary: Is There a Significant Difference in Relapse and Complication Rate of Surgically Assisted Rapid Palatal Expansion Using Tooth-Borne, Bone-Borne, and Orthodontic Mini-Implant-Borne Appliances (Ploder et al, 2020)?

Resident Commentary: Is There a Significant Difference in Relapse and Complication Rate of Surgically Assisted Rapid Palatal Expansion Using Tooth-Borne, Bone-Borne, and Orthodontic Mini-Implant-Borne Appliances (Ploder et al, 2020)?

Comparison between two screws for maxillary expansion: a multicenter randomized controlled trial on patient's reported outcome measures.

The objective of this study was to compare an expansion screw of the maxilla that generates moderate and continuous forces versus a conventional screw for rapid maxillary expansion (RME) on patient-reported outcome measure during the first 12 weeks of treatment. This is a superiority, multicenter, two-arm parallel balanced randomization trial. Patients in the mixed dentition were included with a transverse discrepancy between the two arches of at least 3 mm. An expansion screw using moderate continuous forces (Leaf group, treated with an expansion screw with Ni-Ti springs) was compared to a conventional RME screw that generates intermittent heavy forces (RME group). The primary response variable was the visual analogue scale (VAS) on pain calculated in the first 12 weeks of therapy. The VAS on difficulty on speaking and oral hygiene, patient satisfaction, and complications were also evaluated. A computer-generated block randomization was used with allocation concealed in sequentially numbered opaque-sealed envelopes. Blinding was not applicable. 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. The mean of the VAS for pain was 0.3 ± 0.4 in the Leaf group and 0.6 ± 0.5 in the RME group. The difference was -0.3 (95 per cent CI from -0.5 to -0.0; P = 0.017) in favour of the Leaf group. The difference in pain was marked in the first week (Leaf group 2.2 ± 2.3; RME group 3.7 ± 2.6; difference -1.5; 95 per cent CI from -2.7 to -0.3; P = 0.019). Patients in the Leaf group experienced a lower degree of pain, especially during the first week following the application of the expander. For the other variables, no significant differences were reported between the two treatments. The study was registered in the ISRCTN register on 8 November 2016 with the number ISRCTN18263886.

The impact of tooth-borne vs computer-guided bone-borne rapid maxillary expansion on pain and oral health–related quality of life: A parallel cohort study

The primary aim of this study was to investigate and compare perceived pain intensity and oral health-related quality of life (OHRQOL) results during the activation phase of rapid maxillary expansion (RME), with tooth-borne and bone-borne devices. In addition, a secondary aim of this study was to evaluate the correlation between pain scales and the shortened Oral Health Impact Profile (OHIP-14) questionnaire. Thirty-six subjects (16 girls and 20 boys) with a mean age of 12.3years (standard deviation, 0.82years) were randomized into 2 groups. Group A received treatment with hyrax appliance, and group B received a computer-guided skeletal RME appliance. The same type of expansion screw and screw activation or expansionprotocol were used. Two rating scales were used to assess the subject's pain during the activation phase of RME: a Graphic Rating Scale for Pain (GRS) and the Wong-Baker Faces Pain Scale (FPS). The OHIP-14 was used to evaluate the impact of RME on OHRQOL before the beginning of the treatment at day 3 and day 7 follow-ups. Painkillers were forbidden during the active phase of RME. Descriptive statistics, Student t test, and Pearson correlation were used. Significance was set at P≤0.05. A total of 36 subjects, divided into 2 groups, were treated in the study. Regarding the level of pain, the Student t test showed statistically significant higher pain in group B-although only on the first day of screw activation (GRS, P=0.01; FPS, P<0.01). For the following days, there were no significant differences in pain levels between groups. The OHIP-14 showed no statistically significant difference at baseline (P=0.32) and day 3 (P=0.88) and day 7 (P=0.85) follow-ups between the 2 groups. The Pearson correlation coefficient showed a statistically significant association between the 2 different scales of pain (GRS and FPS) but not a statistically significant correlation between GRS and FPS scales and OHIP-14. A higher perceived pain intensity in the patients treated using a bone-borne computer-guided skeletal RME appliance was limited to the first day of screw activation. There were no statistically significant differences between the 2 types of treatment in terms of their impact on OHRQOL and no statistically significant correlation between pain scales and the OHIP-14 questionnaire.

Two Different Techniques for Alveolar Ridge Expansion

Abstract: Aim of the study: To evaluate the efficacy of two different techniques for maxillary alveolar ridge expansion, the osteotome and screwexpander. Patients and methods: This study was carried out on 16 healthy male patients received 16 implants. Average age 40 years. Each patient has partial edentulous maxilla with bone width not less than 4 mm and height not less than 10 mm. The patients were divided into two equal groups. In group I, implant site was prepared by osteotomes of increasing diameter to reach the planned osteotomy width, group II, implant site was prepared by expansion screws of increasing diameter to reach the planned osteotomy width. Clinical evaluation was done 24 hours postoperatively for edema, wound dehiscence, pain and signs of infection and regular checkups were done weekly during the first month. Radiographic evaluation using CBCT was done after 3 and 9 months postoperatively to measure bone density around inserted implants and vertical bone loss. Implant stability was measured by using Osstell ISQ device for all the implants of the two groups after 6 months (before loading) and after 9 months. Results: Radiographic evaluation showed significant higher bone density and lesser vertical bone loss around the inserted implants in group I than in group II after 3 and 9 months. Also, implant stability measurements at six and nine months showed highly significant values in group I more than in group II. Conclusion: Maxillary alveolar ridge expansion with osteotome is superior to screwexpander regarding to bone density and osseointegration.

Clinical and Radiographic Outcomes of a Novel Transalveolar Sinus Floor Elevation Technique.

The aim of this study was to evaluate the clinical and radiographic outcomes of the "vertically expander screw" (VES) technique as a novel approach for maxillary sinus floor elevation and simultaneous implant placement. Forty-four patients (26 females, 18 males) received 71 implants with simultaneous transalveolar sinus floor elevation via the VES technique. The threaded bone expanders were used to elevate the sinus floor as well as bone expansion. The patients were followed-up on a regular basis, and final clinical and radiographic examinations were performed at least 24months following functional loading. Statistical analysis was conducted using the Chi-square test, the correlation coefficient, and the independent t test (p < 0.05, 95% confidence interval). All implants showed successful osseointegration. The mean marginal bone loss (MBL; 0.38 ± 0.75mm) at the site of premolars was not significantly different from the value at the site of molars (0.17 ± 0.50mm). The mean intrasinus bone gain (IBG) was not significantly different (3.47 ± 1.22mm and 4.11 ± 1.67mm, respectively; p = 0.92). Evaluation of implant success index (ISI) score revealed no difference between the premolars and molars (p = 0.12). Despite the limitations of the present study, it seems that the VES technique and simultaneous implant placement in carefully selected cases may result in promising outcomes. Insufficient alveolar bone height and poor bone quality often complicate implant placement in the edentulous posterior maxilla. The VES technique and simultaneous implant placement can bring about favorable clinical and radiographic outcomes and high survival rate in carefully selected cases.

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.

Asymmetric expansion: An innovative approach

Practitioners select expansion treatment appliances based on their personal experiences and on the patient’s age and malocclusion. Many attempts have been made to produce greater expansion in the maxillary canine regions. Conventional devices for rapid maxillary expansion (RME) are limited to one direction, along the axis of the expansion screw, and thus cannot provide differential expansion. In this case report, we aimed to expand the maxillary arch asymmetrically according to the requirement of the case. Keywords: Maxillary expansion, Asymmetric, Jackscrew.