Hyrax Expander Research Articles

Evaluation of palate morphology in patients treated with leaf expander and hyrax expander: A geometric morphometric analysis.

The aim of this study was to evaluate changes in shape of the palatal vault after maxillary expansion with hyrax expander (HE) and leaf expander (LE), using 3D Geometric Morphometric Analysis. Overall, 250 patients (110 M, 140 F) with maxillary transverse deficiency were selected for this study. In this study, 127 subjects were treated with HE, 123 with LE. Digital dental models were obtained pre-treatment (T0) and after 12 months from the cementation of the device (T1) and processed by means of a digital scanner. Linear and morphometric analyses were conducted to determine the effects of each appliance on dental measurements and palatal shape, and a multiple linear regression was performed to analyse the influence of anchorage and appliance type on final shape. Morphometric analysis showed that there was a lowering of the palatal vault in the HE group, while in the LE group it remained unchanged: the difference in palatal shape at time T0 and T1 was statistically significant in both treatments (HE vs. LE). In the HE group, the change in shape also included the upper part of the palatal vault in the vertical dimension, while in the LE group the change in shape interested mainly palatal shelves and the lower portion of the palate. Both LE and HE produce clinically significant changes in the morphology of the palatal vault.

Effect of rapid maxillary expansion on intracranial pressure

ObjectiveThe aim of this study was to evaluate the effects of rapid maxillary expansion on the optic nerve sheath diameter and to examine its possible effects on intracranial pressure. Design20 patients with bilateral crossbite were selected. Hyrax Expander was applied and activated twice daily until the overcorrection was achieved. The optic nerve sheath diameter (ONSD) was measured via ultrasonography before the first activation (T0), then repeated after 1 (T1) and 10 min (T2). At the end of the expansion, ONSD was measured (T3) again, then the screw was activated for the last time, and measurements were repeated after 1 (T4) and 10 min (T5). The Friedman test was performed to compare the changes, and The Wilcoxon Signed-Rank test was done to determine the significant intergroup changes (p < 0.05). ResultsThe ONSD increased significantly 1 min after the activations (T0-T1 and T3-T4) (P < 0.05). The ONSD values measured 10 min after the activations also increased significantly compared to the baseline values (T0-T2 and T3-T5) (P < 0.05). ConclusionThe activation of maxillary expansion appliances increased the optic nerve sheath diameter in adolescents. Therefore, orthodontists should be careful with patients at risk of intracranial hypertension.

CBCT comparison of dental, dentoalveolar and skeletal treatment results of Hyrax expander and monocortical hybrid expander in late-adolescence

CBCT comparison of dental, dentoalveolar and skeletal treatment results of Hyrax expander and monocortical hybrid expander in late-adolescence

Vertical and transverse treatment effects of Invisalign First system compared to Hyrax maxillary expanders with fixed appliances in mixed dentition patients.

To compare vertical and transverse changes in mixed dentition patients treated with the Invisalign First System (IFS) to those treated with a banded hyrax expander with fixed appliances (Hyrax) and control groups, and to assess the efficiency rate of dental arch expansion with IFS. The study included 80 mixed dentition patients, with 40 in each group (IFS and Hyrax) and 40 controls from the American Association of Orthodontists Foundation Craniofacial Growth Legacy Collection. Skeletal and dental vertical dimension changes and arch width changes between pretreatment (T1) and posttreatment (T2) were evaluated. Age at T1, time interval (T1-T2), sex, and Angle class did not significantly differ among the groups. Mandibular plane angle changes showed a similar reduction for the control and IFS groups, with no changes in the Hyrax group. However, the differences among the three groups did not reach statistical significance (P = .06). The Hyrax group showed significantly greater expansion in maxillary intermolar width compared to the IFS group, 4.4 vs 2.5 mm, respectively. The efficiency of maxillary expansion using IFS ranged from 52.3% to 76.87%. During the mixed dentition stage, no significant changes occurred in vertical dimensions among the control, Hyrax, and IFS groups. Although there was a trend suggesting a greater reduction in mandibular plane angle in the IFS group compared to the Hyrax group, this may not be clinically significant given the less than 1° difference. IFS can be a viable option for addressing mild arch width deficiencies, with a predictable increase in intermolar width of approximately 2.5 mm.

Comparison of 3D-printed and laboratory-fabricated Hyrax on stress distribution and displacement of the maxillary complex: a 3D finite element study

ObjectiveTo analyze and compare the effects of a traditional laboratory-fabricated Hyrax expander (T-Hyrax) and two different 3D-printed Hyrax expander models relative to tension points, force distribution, and areas of concentration in the craniofacial complex during maxillary expansion using finite element analysis.Materials and methodsThree maxillary expanders with similar designs, but various alloys were modeled: a T-Hyrax, a fully printed Hyrax (F-Hyrax), and a hybrid printed Hyrax (H-Hyrax). The stress distributions and magnitude of displacements were assessed with a 5 mm expansion in a symmetrical finite element model. The areas of interest included the teeth, alveolar processes, midpalatal suture, nasal complex, circummaxillary sutures (CS), and the expanders themselves.ResultsThe highest stress value (29.2 MPa) was found at the midpalatal suture of the F-Hyrax, while the lowest stress (0.90 MPa) was found at the temporozygomatic suture in the T-Hyrax. On average, the F-Hyrax increased stress at the CS by 24.76% compared with the T-Hyrax and H-Hyrax. The largest displacements were found at the upper incisor (U1) and anterior nasal spine (ANS). The findings indicated an average increase of 12.80% displacement at the CS using the F-Hyrax compared to the T-Hyrax.ConclusionThe F-Hyrax exerts more stress and displacement on the maxilla than both the T-Hyrax and H-Hyrax, where the weak link appears to be the solder joint.

Comparison of alveolar bone morphology after expansion with hybrid and conventional Hyrax expanders.

To compare the buccal and palatal bone changes of maxillary posterior teeth produced by hybrid hyrax (HH) and conventional hyrax (CH) expanders in growing patients. A sample of 32 patients with posterior crossbites in the late mixed dentition was recruited and randomly allocated into two groups. Group HH was composed of 18 individuals with a mean age of 10.7 years (six female, 12 male) treated with a hybrid expander with two anterior parasagittal miniscrews. Group CH was composed of 14 individuals with a mean age of 11.4 years (six female, eight male) treated with a conventional Hyrax expander. Cone-beam computed tomography (CBCT) exams were obtained before expansion (T1) and after 11 months when the expander was removed (T2). Buccal and palatal bone plate thickness and height of maxillary posterior teeth were measured. Intergroup comparisons were performed using t or Mann-Whitney tests (P < .05). The CH group showed greater decreases of the buccal bone plate height (mean change: 1.27 mm) at the maxillary first premolars compared to the HH group (mean change: 0.11 mm, P = .001). No intergroup difference was found for changes in the buccal and palatal bone thickness. Hybrid expanders showed a tendency to cause less negative impact on the buccal bone plate height of first premolars compared to conventional Hyrax expanders. However, the difference was not clinically significant. Both hybrid and conventional Hyrax expanders are safe for the alveolar bone morphology in the late mixed dentition.

Multidisciplinar orthopedic treatment of facial asymmetry in a pediatric patient: case report

Temporomandibular joint ankylosis (TMJA) may be fibrous or bony (resulting from the fusion of articular surfaces, glenoid fossa, and mandibular condyle). A multidisciplinary approach is necessary to successfully rehabilitate patients with this condition since it can cause problems related to psychosocial, nutritional, facial, and occlusal factors. Depending on the patient’s age, orthotic intervention may be necessary in order to correct the malocclusion caused by TMJA. This article presents the case of a pediatric patient with idiopathic left TMJA who underwent multidisciplinary treatment at a reference center for craniofacial anomalies in western Parana. Balters Bionator orthopedic appliances were initially used, followed by rapid maxillary expansion using a Hyrax expander. This resulted in improved masticatory, esthetic, and speech functions, particularly mouth opening, as well as partial correction of mandibular asymmetry and the occlusal plane within the limits of the case. The use of functional and mechanical orthopedic appliances contributed to improved facial function and esthetics, and the multidisciplinary team’s care was essential to improving the patient’s quality of life during the rehabilitation process.

Effects of novel microimplant-assisted rapid palatal expanders manufactured by 3-dimensional printing technology: A finite element study

The expansion effects of several new microimplant-assisted rapid palatal expanders (MARPEs) manufactured by 3-dimensional printing technology were evaluated by finite element analysis (FEA). The aim was to identify a novel MARPE suitable for treating maxillary transverse deficiency. The finite element model was established using MIMICS software (version 19.0; Materialise, Leuven, Belgium). First, the appropriate microimplant insertion characteristics were identified via FEA, and several MARPEs with the above insertion patterns were manufactured by 3-dimensional printing technology. Then, the stress distribution and displacement prediction of the 4 MARPEs and hyrax expander (model E) were evaluated via FEA: bone-borne (model A), bone-tooth-borne (model B), bone-mucous-borne (model C), bone-tooth-mucous-borne (model D). Monocortical microimplants perpendicular to the cortical bone on the coronal plane resulted in better expansion effects. Compared with a conventional hyrax expander, the orthopedic expansion of each of the 4 MARPEs was far larger, the parallelism was greater, and the posterior teeth tipping rate was lower. Among them, the expansion effects of models C and D were the best; the von Mises peak values on the surfaces of the microimplants were smaller than those of models A and B. This study may demonstrate that the 4 MARPEs obtained more advantageous orthopedic expansion effects than a hyrax expander. Models C and D obtained better biomechanical effects and had better primary stability. Overall, model D is the recommended expander for treating maxillary transverse deficiency because its structure acts like an implant guide and is beneficial for the accurate insertion of the microimplant.

Effects of rapid maxillary expansion on sleep disturbance scale for children: A longitudinal CASE-series study.

To evaluate the effects of rapid maxillary expansion (RME) on Sleep Disturbance Scale for Children (SDSC) with maxillary atresia. The sample consisted of 27 paediatric patients evaluated through a Brazilian version of the SDSC, answered by their guardians at the following experimental time points: T0 (before installing the Hyrax expander), T1 (on the day of expander stabilization), T2 (3 months after expander stabilization), T3 (immediately after expander removal, following 6 months of retention), and T4 (3 months post-retention). Multilevel Poisson analysis adjusted for repeated measures was performed to compare outcomes across the assessment time points. The mean age of patients was 9.1 years (SD = 1.46). The total SDSC scores decreased and were statistically significant from T2 onwards (P < .01), with a decrease of 24% at T4 compared with T1 (IRR 0.76; 95% CI 0.69-0.84). The mean scores at T4 were already lower than the cutoff point for risk of sleep disorders. Regarding the specific domains, there was a significant reduction in sleep breathing disorders, sleep-wake transition disorders, and disorders of excessive somnolence as of T2 (P < .01), T3 (P < .05) and T4 (P < .05), respectively. RME in children with maxillary atresia had a positive effect on the reduction of total SDSC scores after 3 months of expander stabilization, sustained over 6 and 9 months and significant reduction in sleep breathing disorders domain, sleep-wake transition disorders domain, and disorders of excessive somnolence domain over time points.

Dento-skeletal effects of different rapid maxillary expanders for growing patients-which is better?

Single-blind, two-arm parallel-group randomised controlled trial. Patients aged 11-14 years old attending for comprehensive orthodontic treatment between January and July 2018. All subjects needed to have the following: present upper first premolars and first permanent molars; transverse maxillary deficiency; unilateral or bilateral posterior crossbite. The exclusion criteria was: cleft lip or palate, previous orthodontic treatment; congenital deformity; absent permanent teeth. Rapid maxillary expansion via two techniques were used and placed by the same orthodontist. Group A were treated via the tooth-bone-borne Hybrid Hyrax expander, Group B had the tooth-borne (hyrax) expander. CBCT scans of the maxilla were taken before treatment and 3 months after the activation phase when the appliances had been removed. Analysis of the dental and skeletal changes was completed via measuring pre and post treatment CBCT scans using Dolphin software for Group A and Group B. Measurements included: specific naso-maxillary widths in the first premolar region (i.e. nasal cavity, nasal floor, maxilla, palate), naso-maxillary widths in the first molar region, premolar/molar inclination, buccal cusp distance, and apices distance, as well as suture maturation. Baseline characteristic data was compared using one-way ANOVA. Intergroup comparison of changes was analysed using ANCOVA. P < 0.05 (5%) was considered statistically significant. Inter-rater reliability was assessed using correlation coefficient. Skeletal effects: The Hybrid Hyrax patients (HHG) showed a significantly higher increase in dimensions in the nasal cavity, nasal floor and maxilla in the premolar region only, of 1.5 mm, 1.4 mm and 1.1 mm, respectively, compared to the Hyrax expander patients (HG), to a 5% significance level. The HHG showed a significantly higher increase in dimensions in the nasal cavity of 0.9 mm, in the molar region, compared to the HG. Dental effects: Premolar inclination was significantly higher in the HG, with the difference being -3.2 degrees on the right 1st premolar and -2.5 degrees on the left 1st premolar. The higher the amount of activation, the higher the nasal skeletal changes in the Hybrid Hyrax group. The Hybrid Hyrax (tooth-bone-borne expander) resulted in increased skeletal dimension changes (i.e. in the nasomaxillary structures in the first premolar region, and nasal cavity in the first molar and first premolar region) and only minimal premolar inclination/tipping compared to the Hyrax (tooth-borne expander). There were however no differences between the expanders for position of premolar or molar apices, or molar crowns.

Effect of maxillary constriction orthodontic correction using a fixed appliance with a screw in teenagers during a growth spurt

Relevance. The research is relevant because of a high prevalence of anterior and posterior crowding in children with mixed and permanent dentition (from 42 to 86 %), for whom the correction of the dentition form and the size is recommended by fixed expanding appliances with a screw. After the teenage growth spurt, the growth and development of jaws end, steady pathological signs form, there are psychological problems in a face and smile selfperception, and the question of the orthodontic treatment duration arises.Purpose. To study the effectiveness of treatment of patients with maxillary premolar area constriction during growth spurt using two modifications of fixed Hyrax expander.Material and methods. We examined 22 male patients aged 10.6 to 13 y.o. (average age 11.2 ± 1.6 years old) with permanent dentition, constriction of the posterior teeth and crowding of incisors, treated with a fixed expander (Hyrax appliance) in the upper jaw during the growth spurt. The patients formed two groups. Group 1 (n = 11) had the Hyrax screw at the level of the upper first premolars, and Group 2 (n = 11) had the Hyrax lock located at the first permanent molars. The patients activated the expander independently by ¼ turn every other day for six months. Then the appliance remained in the mouth for three months. We studied the maxillary expansion results on plaster models before and after six months of the expander fixation using the Tonn, Pont, Korkhaus, Bolton method.Results. The study has established that orthodontic correction of transversal abnormalities with a fixed Hyrax expander affects the maxillary posterior teeth expansion, changes their parameters and improves their movement. At the same time, in Group 1, the width between the first premolars and the first molars reached the norm calculated from the sum of the mesiodistal dimensions of the upper incisors, and in Group 2, the width between the first permanent molars exceeded the normal, and inter-first-premolar distance did not reach the normal values for three months of activation.Conclusion. Fixed Hyrax expander showed the best results if the screw was at the level of first premolars during the teenage growth spurt.

Idiopathic osteosclerosis in a Class III patient treated with facemask therapy and hybrid hyrax- A case report

Class III malocclusion is the most common form of malocclusion requiring orthognathic surgery. Hence, early diagnosis and intervention is often beneficial in reducing the severity of the problem. Protraction of the maxilla using a facemask accompanied by rapid maxillary expansion (RME) is the ideal treatment option for growing patients with Class III malocclusion and deficient maxilla. Idiopathic osteosclerosis is an asymptomatic, benign lesion that usually develops early in life. Its origin could be associated to reaction to inflammation or occlusal trauma, occurring at the time of teeth transition. Here, in this case report, we have showed the successful management of a Class III adolescent patient, diagnosed with idiopathic osteosclerosis, with face mask therapy and hybrid hyrax expansion appliance following Alt-RAMEC protocol. Also, we have showed the management of disturbed wound healing which might occur after palatal implant removal.

Pain and discomfort perception during miniscrew-anchored maxillary protraction: secondary data analysis of a randomized clinical trial.

To compare the perception of pain and discomfort of patients and guardians during treatment between miniscrew-anchored maxillary protraction (MAMP) therapy using Hybrid (HH) and Conventional Hyrax (CH) expanders. Group HH was composed of 18 subjects (8 female, 10 male; initial age: 10.80 years) with Class III malocclusion treated with a hybrid expander in the maxilla and two miniscrews in the anterior region of the mandible. Class III elastics were used from maxillary first molar to mandibular miniscrews. Group CH was composed of 14 subjects (6 female, 8 male; initial age: 11.44 years) treated with a similar protocol except for conventional Hyrax expander. Pain and discomfort of patients and guardians were assessed using a visual analog scale immediately after placement (T1), after 24 hours (T2), and 1 month after appliance installation (T3). Mean differences (MD) were obtained. Intergroup and intragroup timepoint comparisons were performed using independent t-tests, analysis of variance for repeated measures and Friedman test (P < 5%). Both groups demonstrated similar levels of pain and discomfort with a significant decrease after 1 month of appliance placement (MD: 4.21; P = .608). Compared to patient perceptions, guardians reported a higher level of pain and discomfort at all timepoints (MD, T1: 13.91, P < .001; T2: 23.15, P < .001; T3: 9.35, P = .008). MAMP therapy with HH and CH produced similar levels of pain and discomfort after appliance installation until 1 month after treatment. Pain and discomfort may not influence the choice between HH and CH expanders.

Prediction Model for Future Success of Early Orthopedic Treatment of Class III Malocclusion

This study aimed to identify predictors for successful post-treatment outcomes in early orthopedic class III malocclusion treatment with a facemask and hyrax expander appliance. The study was performed on lateral cephalograms from 37 patients at the start of treatment (T0), post-treatment (T1), and a minimum of three years after treatment (T2). The patients were grouped as stable or unstable according to the existence of a 2-mm overjet at T2. For statistical analysis, independent t-tests were used to compare the baseline characteristics and measurements of the two groups, considering a significance level of < 0.05. Thirty variables of pretreatment cephalograms were considered during logistic regression analysis to identify predictors. A discriminant equation was established using a stepwise method. The success rate and area under the curve were calculated, with AB to the mandibular plane, ANB, ODI, APDI, and A-B plane angles as predictors. The A-B plane angle was the most significantly different between the stable and unstable groups. In terms of the A-B plane angle, the success rate of early class III treatment with a facemask and hyrax expander appliance was 70.3%, and the area under the curve indicated a fair grade.

A retrospective comparison of two protocols for correction of skeletal Class III malocclusion in prepubertal children: hybrid hyrax expander with mandibular miniplates and rapid maxillary expansion with face mask

BackgroundThis study compared the skeletal and dental effects of a hybrid maxillary expander with mandibular miniplates (HE-MP) and Class III elastics to conventional tooth-borne rapid maxillary expander and face mask (RME–FM) in skeletal Class III treatment.MethodsThis retrospective study included 36 skeletal Class III patients. Eighteen patients (mean age 10.24 ± 1.31 years) were treated with a hybrid expander, two mandibular L-shaped miniplates and full-time Class III elastics (HE-MP group). Their results were compared to a group of patients treated with conventional RME–FM (n = 18; mean age 10.56 ± 1.41 year). Radiographs were taken before (T1) and after treatment (T2). All patients were in cervical maturation stages CS1–CS3 at T1. The measured outcomes were the changes in sagittal and vertical skeletal and dental cephalometric measurements.ResultsTreatment time was approximately 15.5 ± 2.8 months with the HE-MP and 11.85 ± 3.41 months for the RME–FM. The Class III malocclusion was corrected in both groups with significant changes. The maxilla advanced more in the HE-MP group, with an increase in SNA of 4.26° ± 2.15° compared to 1.14 ± 0.93 in the RME–FM group (p < 0.001). The effect on the mandible was similar in both groups, while the overall skeletal change was significantly greater with HE-MP, with an increase in the ANB of 5.25° ± 2.03° and a Wits appraisal increase of 6.03 ± 3.13 mm, as opposed to 2.04° ± 1.07° and 2.94 ± 1.75 mm with the RME–FM (p < 0.001). Dental changes were significantly higher with RME–FM, with an increase in incisor inclination (U1-SN) of 5.02° ± 3.93° (p < 0.001), with no significant changes in the HE-MP group. The mandibular incisors retroclined by 5.29° ± 3.57° at L1-MP with the RME–FM, while they advanced slightly with the HE-MP by 2.87° ± 5.37° (p < 0.001).ConclusionThe use of skeletal anchorage for maxillary expansion and protraction significantly increases skeletal effects and reduces dental side effects compared to tooth-borne maxillary expansion and protraction. These results need to be investigated in the long term.

CHANGES IN WEIGHT AND BODY MASS INDEX OF PATIENTS UNDERGOING HYRAX EXPANDER THERAPY

Objective: To determine the changes in weight and body mass index of patients with a Hyrax expander in one month and three months after cementation. Methodology: A total of 130 patients from 10-14 years of age with an indication of Hyrax expander were included in this quasi-experimental study. Patients were enrolled through the convenience sampling technique. The study was carried out from November 2019 to January 2022 at the Department of Orthodontics, Khyber College of Dentistry, Peshawar. The Height and weight were measured at 3-time intervals; T0 (before initiation of treatment), T1 (1 month after appliance cementation), and T2 (3 months after appliance cementation). Data analysis was done using IBM SPSS 25.0. The body mass index at T0, T1, and T2, along with means, standard deviations, frequencies, and percentages, were calculated. A paired samples t-test was employed to check the mean differences in weight and body mass index at T0, T1, and T2. A p-value of &lt;0.05 was considered significant. Results: The mean age of 130 patients was 11.81 ± 1.31 years. The number of male patients were 54 out of 130 and female patients were 76 out of 130. The mean difference in weight loss at T0-T1 (0.83 kg ±2.69) was statistically significant.(p =0.001) So was the mean difference of body mass index (0.43 kg/m2 ± 0.81) at T0-T1. The mean differences in both weight and body mass index were insignificant at T2. Conclusion: A decrease in body mass index and weight loss is observed in patients undergoing hyrax expander therapy 1 month after initiation of treatment.

The comparison of biomechanical effects of the conventional and bone-borne palatal expanders on late adolescence with unilateral cleft palate: a 3-dimensional finite element analysis

BackgroundPatients with unilateral cleft lip and palate were associated with different nasomaxillary complex from the normal population. Although the biomechanical effects of conventional rapid palatal expansion (Hyrax expansion) and bone-borne rapid palatal expansion (micro-implant-assisted expansion) in non-cleft patients have been identified by multiple studies, little is known in patients with unilateral cleft lip and palate. The purpose of this study was to investigate and compare the biomechanical effects of the conventional and bone-borne palatal expanders in a late adolescence with unilateral cleft lip and palate.MethodsA cone beam CT scan of a late adolescence with unilateral cleft lip and palate was selected to construct the three-dimensional finite element models of teeth and craniofacial structures. The models of conventional and born-borne palatal expanders were established to simulate the clinical maxillary expansion. The geometric nonlinear theory was applied to evaluate the Von Mises stress distribution and displacements in craniofacial structures and teeth.ResultsBone-borne palatal expander achieved more transverse movement than conventional palatal expander in the whole mount of craniofacial regions, and the maximum amount of expansion was occurred anteriorly along the alveolar ridge on cleft-side. The expanding force from born-borne palatal expander resulted in more advancement in nasomaxillary complex than it in conventional palatal expander, especially in the anterior area of the minor segment of maxilla. Stresses from the both expanders distributed in similar patterns, but larger magnitudes and ranges were generated using the bone-borne expander around the maxillary buttresses and pterygoid plates of sphenoid bone. The maximum expanding stresses from born-borne palatal expander were concentrated on palatal slope supporting minscrews, whereas those from conventional palatal expander were concentrated on the anchoring molars. In addition, the buccal tipping effect of teeth generated using the bone-borne expander was less than it using the conventional palatal expander.ConclusionBone-borne expander generated enhanced skeletal expansion at the levels of alveolar and palate in transversal direction, where the miniscrews contributed increased expanding forces to maxillary buttresses and decreased forces to buccal alveolar. Bone-borne expanders presented a superiority in correcting the asymmetric maxilla without surgical assistant in late adolescence with unilateral cleft lip and palate.

Effectiveness of low-level laser therapy in facilitating maxillary expansion using bone-borne hyrax expander: A randomized clinical trial.

The objective of this randomized clinical trial was to study the skeletal and dental effects of low-level laser therapy (LLLT) along with a miniscrew-assisted expander (Hyrax) after six months of retention. After sequence generation, concealed allocation, and implementation, 24 female patients were randomly divided (1:1) into two-groups: bone-borne rapid palatal expansion (BBE) without LLLT (n = 12) and BBE with LLLT (n = 12). Eligibility criteria included female patients aged 10-13 years old with bilateral posterior crossbites. Intraoral and extraoral photographs, cone-beam computed tomography images, and digital study models were obtained before expansion and six months after retention. The 7 mm Hyrax appliance was anchored to four palatal mini-screws, which were activated twice daily for 15 days, then locked and kept in place as a retainer. LLLT was performed in the laser group during expansion and retention, according to the guidelines provided. The records of 24 patients were analyzed. According to the post-retention measurements, both groups showed a significant increase in nasal and maxillary widths and total facial height. In the laser group, the Sella-Nasion-Point A and Point A-Nasion-Point B angles and the interpremolar apical distance were significantly increased. Within the limitations of this study, the results suggest that the parameters and protocol of LLLT do not clinically affect the efficiency of BBE in prepubertal and pubertal patients.

Update of the classification of midpalatal suture behaviour after surgically assisted rapid maxillary expansion using computed tomography

The aim of this study was to update the midpalatal suture classification after surgically assisted rapid maxillary expansion (SARME) using computed tomography (CT). Thirty-five patients with a transverse maxillary deficiency and unilateral or bilateral posterior crossbite underwent SARME with osteotomy of the pterygoid apophysis of the sphenoid. CT was performed before installation of the Hyrax expander appliance and after the final activation. Opening of the midpalatal suture was classified into three types: type I, total midpalatal suture opening from anterior nasal spine (ANS) to posterior nasal spine (PNS); type II, partial midpalatal suture opening from ANS to the transverse palatine suture, with partial or non-existent opening of the midpalatal suture posterior to the transverse palatine suture; type III, complete maxillary opening from ANS, but not of PNS, because a paramedian fracture completed the opening of the hard palate. Type I was observed in 42.8% of the patients, type II in 40%, and type III in 17.2%. Opening of the transverse palatine suture was found in all midpalatal suture opening patterns and was more frequent in type III, followed by type II and type I. CT was used to update the classification of midpalatal suture patterns, with the inclusion of type III: total opening of the hard palate due partly to opening of the midpalatal suture and partly to a paramedian fracture.

Hyrax versus Leaf expander in growing patients, what about adverse dental effects? A retrospective study

Transverse discrepancy is a Common problem in young patients. Many devices are employed to expand the palatal dimension, with different characteristics and biomechanical aspects. The Leaf expander, a new-born appliance containing nickel-titanium springs, free from activation by parents. We compared the maxillary and mandibular dental effects of Leaf expander to conventional Hyrax in growing patients. All patients who met the eligibility criteria between the period from January 2017 to December 2019 were included. The patients had transverse inter-arch discrepancy of at least 5mm and were treated with Hyrax expander (HEX) or Leaf expander (LEX). All patients had complete follow-up of expansion by remote monitoring. An algorithm established distances between the teeth. It was also used to measure the change in dental axes. In the maxilla, LEX caused more tipping on the canines and premolars but significantly less on the molars compared to HEX: -0.154̊ vs. 3.05̊ (P<0.001). In the mandible, LEX caused a greater increase in arch widths and tipping (P<0.02) in the molars and second premolars, but not in the other teeth. No correlation was demonstrated between mandibular dental movements and increased maxillary arch widths. Alternatively, for the two devices, expansion and tipping were correlated within each dental arch (r>0.4). The LEX produced more tooth movement on average than the HEX, except for the maxillary first molars. Several correlations exist between the movements within each arch for the two devices, most often between tipping and expansion.