Sub-membranous actin rings in the axon initial segment are resistant to the action of latrunculin.

The axon initial segment (AIS) comprises a sub-membranous lattice containing periodic actin rings. The overall AIS structure is insensitive to actin-disrupting drugs, but the effects of actin-disrupting drugs on actin rings lack consensus. We examined the effect of latrunculin A and B on the actin cytoskeleton of neurons in culture and actin rings in the AIS. Both latrunculin A and B markedly reduced the overall amount of F-actin in treated neurons in a dose-dependent manner, but the periodicity of actin rings remained unaffected. The insensitivity of AIS actin rings to latrunculin suggests they are relatively stable.

Can the use of skeletal anchors in conjunction with fixed functional appliances promote skeletal changes? A systematic review and meta-analysis.

BACKGROUND: Recently, the use of skeletal anchors in conjunction with fixed functional appliances (FFAs) has been advocated to enhance skeletal changes and reduce proclination of the lower incisors. OBJECTIVE: To compare the skeletal and dento-alveolar effects of the use of FFAs with and without skeletal anchorage (miniscrews or miniplates). SEARCH METHODS: Unrestricted electronic search of six databases and additional manual searches were performed up to July 2015. ELIGIBILITY CRITERIA: Randomized and prospective non-randomized controlled trials directly comparing the use of FFA with and without skeletal anchorage, and involving growing patients with Class II malocclusion. DATA COLLECTION AND ANALYSIS: Skeletal and dento-alveolar outcomes data were extracted in pre-defined sheets to collect study characteristics by two authors independently. After evaluating risk of bias, the standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated with random-effects models. Subgrouping was pre-planned on the basis of the skeletal anchorage type used. Additional subgroup analysis was performed on the basis of the type of FFA used and the study design. RESULTS: Seven studies were evaluated, and only five of which were included in the meta-analysis. The analysis included data from 157 Class II subjects (77 treated with FFA and skeletal anchorage, and 80 with FFA alone). Random-effects meta-analysis demonstrated no significant differences in the mandibular length and SNB angle changes [SMD = 1.98 (95% CI -0.11 to 4.07) and 1.20 (95% CI -0.37 to 2.77) respectively]. Significant differences were found between the inclination changes of lower and upper incisors [SMD = -1.43 (95% CI -2.59 to -0.27) and SMD = -1.04 (95% CI -1.57 to -0.51) respectively]. Subgroup differences were highly significant in most of the outcomes. CONCLUSIONS: The studies reviewed provide insufficient evidence to form a conclusion regarding the effects of the use of skeletal anchorage with FFA. The available weak evidence suggests that the use of skeletal anchorage with FFA has no superior skeletal effects but is able to reduce proclination of the lower incisors.

Comparison of patient acceptance of the Forsus Fatigue Resistant Device with and without mini-implant anchorage: a randomized controlled trial.

INTRODUCTION: The objective of this 2-arm parallel randomized controlled trial was to evaluate patient acceptance of the mini-implant anchored Forsus Fatigue Resistant Device (FFRD) (3M Unitek, Monrovia, Calif). METHODS: The study included 32 skeletal Class II girls. The eligibility criteria included a deficient mandible, a horizontal or neutral growth pattern, an increased overjet, and a full set of erupted permanent teeth. After the leveling and alignment stage, FFRDs and mini-implants were inserted; they were removed after the teeth reached an edge-to-edge incisor relationship. The patients were afterward asked to fill out assessment questionnaires regarding their experience with the FFRD. OUTCOMES: The primary outcome of this study was to assess patient acceptance of the appliance and satisfaction with the results. The secondary outcomes were interference with functional activities, noticeability by others, pain, swelling, gum problems caused by the appliance, and appliance breakage. RANDOMIZATION: Computer random sequence generation was done using block sizes of 6 and 4. Allocation concealment was achieved with sequentially numbered opaque sealed envelopes. BLINDING: Blinding of the clinicians and the patients to the intervention was impossible, but it was done for the outcome assessment and the statistician. RESULTS: The 32 patients were randomly allocated in a 1:1 ratio into 2 groups: 16 patients (mean age, 13.25 ± 1.12 years) received the FFRD alone (FFRD group), and 16 patients (mean age, 13.07 ± 1.41 years) had mini-implants in conjunction with FFRDs (FMI group). No statistically significant differences were reported between the 2 groups regarding ease of appliance insertion, noticeability by others, pain, swelling, effects on eating and speech, and gum bleeding; 100% and 87.5% were satisfied with the results in the FFRD and FMI groups, respectively, with a ridit value of 0.57 (95% confidence interval, 0.43-0.71; P = 0.36). No serious harm was observed other than swelling of the cheeks, which occurred in 4 patients. CONCLUSIONS: There were no significant differences between the patients' acceptance of the FFRD and the mini-implant anchored FFRD. They were highly satisfied with the results. Neither group reported significant functional limitations. REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement. FUNDING: The study was self-funded by the authors.

Reticular adhesions are assembled at flat clathrin lattices and opposed by active integrin α5ß1.

Reticular adhesions (RAs) consist of integrin αvß5 and harbor flat clathrin lattices (FCLs), long-lasting structures with similar molecular composition as clathrin-mediated endocytosis (CME) carriers. Why FCLs and RAs colocalize is not known. Here, we show that RAs are assembled at FCLs in a process controlled by fibronectin (FN) and its receptor, integrin α5ß1. We observed that cells on FN-rich matrices displayed fewer FCLs and RAs. CME machinery inhibition abolished RAs and live-cell imaging showed that RA establishment requires FCL coassembly. The inhibitory activity of FN was mediated by the activation of integrin α5ß1 at Tensin1-positive fibrillar adhesions. Conventionally, endocytosis disassembles cellular adhesions by internalizing their components. Our results present a novel paradigm in the relationship between these two processes by showing that endocytic proteins can actively function in the assembly of cell adhesions. Furthermore, we show this novel adhesion assembly mechanism is coupled to cell migration via unique crosstalk between cell-matrix adhesions.

The mammalian endocytic cytoskeleton.

Clathrin-mediated endocytosis (CME) is the major route through which cells internalise various substances and recycle membrane components. Via the coordinated action of many proteins, the membrane bends and invaginates to form a vesicle that buds off-along with its contents-into the cell. The contribution of the actin cytoskeleton to this highly dynamic process in mammalian cells is not well understood. Unlike in yeast, where there is a strict requirement for actin in CME, the significance of the actin cytoskeleton to mammalian CME is variable. However, a growing number of studies have established the actin cytoskeleton as a core component of mammalian CME, and our understanding of its contribution has been increasing at a rapid pace. In this review, we summarise the state-of-the-art regarding our understanding of the endocytic cytoskeleton, its physiological significance, and the questions that remain to be answered.

Measuring Properties of the Membrane Periodic Skeleton of the Axon Initial Segment using 3D-Structured Illumination Microscopy (3D-SIM).

The axon initial segment (AIS) is the site at which action potentials initiate and constitutes a transport filter and diffusion barrier that contribute to the maintenance of neuronal polarity by sorting somato-dendritic cargo. A membrane periodic skeleton (MPS) comprising periodic actin rings provides a scaffold for anchoring various AIS proteins, including structural proteins and different ion channels. Although recent proteomic approaches have identified a considerable number of novel AIS components, details of the structure of the MPS and the roles of its individual components are lacking. The distance between individual actin rings in the MPS (~190 nm) necessitates the employment of super-resolution microscopy techniques to resolve the structural details of the MPS. This protocol describes a method for using cultured rat hippocampal neurons to examine the precise localization of an AIS protein in the MPS relative to sub-membranous actin rings using 3D-structured illumination microscopy (3D-SIM). In addition, an analytical approach to quantitively assess the periodicity of individual components and their position relative to actin rings is also described.

Anchorage control using miniscrews in comparison to Essix appliance in treatment of postpubertal patients with Class II malocclusion using Carrière Motion Appliance.

OBJECTIVES: To evaluate anchorage control using miniscrews vs an Essix appliance in treatment of Class II malocclusion by distalization using the Carrière Motion Appliance (CMA). MATERIALS AND METHODS: Twenty-four postpubertal female patients with Class II, division 1 malocclusion were randomly distributed into two equal groups. CMA was bonded in both groups, and one group was treated with miniscrews as anchorage (12 patients, mean age = 18.0 years) while the other group was treated with an Essix appliance as anchorage (12 patients, mean age = 17.8 years). For each patient, two cone-beam computed tomographic scans were obtained: one preoperatively and another after completion of distalization. RESULTS: In the Essix appliance group, there was a statistically significant anterior movement (2.2 ± 1.43 mm) as well as proclination of the lower incisor (5.3° ± 4.0°), compared to a nonsignificant anterior movement (0.06 ± 1.45 mm) and proclination (0.86° ± 2.22°) in the miniscrew group. The amount of maxillary molar distalization was higher in the miniscrew group (2.57 ± 1.52 mm) than in the Essix appliance group (1.53 ± 1.11 mm); however, the difference was not statistically significant. CONCLUSIONS: Miniscrews led to a decrease in the amount of anchorage loss in the mandibular incisors, both in terms of anterior movement and proclination.

Dental arch changes after anterior open bite treatment in the mixed dentition produced by miniscrew-supported palatal crib vs conventional fixed palatal crib.

OBJECTIVES: To evaluate the dental arch changes produced by the miniscrew-supported palatal crib (MSPC) and the conventional fixed palatal crib (CFPC) after the treatment of patients with anterior open bite (AOB) attributed to the tongue-thrusting habit in the mixed dentition stage. MATERIALS AND METHODS: A total of 26 children aged 8 to 11 years with an AOB were randomly distributed into two equal groups; the MSPC group was treated using a palatal crib supported by two miniscrews inserted paramedially, whereas the CFPC group was treated using a conventional fixed palatal crib soldered to bands. Digital models were obtained pretreatment and after a follow-up duration of 9 months. RESULTS: The MSPC group included 12 participants (9 girls and 3 boys; mean age, 9.4 ± 0.75 years), and the CFPC group included 12 participants (10 girls and 2 boys; mean age, 9.0 ± 0.73 years). The amount of AOB closure was similar in both groups: 3.97 ± 1.44 mm in the MSPC group and 3.97 ± 0.89 mm in the CFPC group. There was significant mesial movement of the maxillary first molar in the CFPC (-1.42 ± 0.99 mm) compared with the MSPC group (-0.53 ± 0.32 mm). CONCLUSIONS: Both appliances resulted in similar improvement in the amount of AOB closure. There was significantly more mesial movement of the maxillary first molars in the CFPC group compared with the MSPC group.

Root resorption associated with maxillary buccal segment intrusion using variable force magnitudes.

OBJECTIVES: To compare the root resorption resulting from miniscrew-supported maxillary posterior dentoalveolar intrusion using two different force magnitudes. MATERIALS AND METHODS: Adult patients with skeletal open bite, indicated for maxillary posterior dentoalveolar intrusion, were recruited and randomly assigned to the comparison or intervention groups. The comparison group involved applying 200 g of intrusive force per segment, which measured 20 g per root, while this force was 400 g per segment in the intervention group, measuring 40 g per root. RESULTS: Twenty participants were included in the final analysis after 2 patients dropped out, 1 in each group, to end up with 10 subjects (200 roots) per group. There was statistically significant root resorption of 0.84 ± 0.96 mm and 0.93 ± 1.00 mm in the comparison and the intervention groups, respectively. However, there was no statistically significant difference between the groups. CONCLUSIONS: Root resorption inevitably took place in association with orthodontic intrusion. However, increasing the magnitude of the intrusive force did not increase the amount of root resorption, either statistically or clinically.

Evaluation of the splint-supported Forsus Fatigue Resistant Device in skeletal Class II growing subjects.

OBJECTIVES: To evaluate the use of the Forsus Fatigue Resistant Device (FFRD), supported with bimaxillary splints, in treatment of skeletal Class II malocclusion. MATERIALS AND METHODS: Data from 46 skeletal Class II females who received either conventional Forsus alone (FFRD group) (15 patients, 12.54 ± 0.90 years), FFRD and bimaxillary splints (splint-FFRD group) (15 patients, 12.29 ± 0.82 years), or were untreated controls (16 subjects, 12.1 ± 0.9 years) were retrieved from previous clinical trials. FFRD was inserted onto the mandibular archwire in the FFRD group after leveling and alignment with multibracket appliances. In the splint-FFRD group, Forsus was inserted between fixed maxillary and mandibular splints. Treatment continued until reaching an edge-to-edge incisor relationship. RESULTS: Both treatment groups failed to induce significant mandibular skeletal effects compared to the normal growth exhibited by untreated controls. The splint-FFRD group showed significant reduction of SNA (-0.88° ± 0.51°) and ANB (-1.36° ± 0.87°). The mandibular incisors showed significant proclination in the FFRD (9.17° ± 2.42°) and splint-FFRD groups (7.06° ± 3.34°). CONCLUSIONS: The newly proposed splint-supported FFRD was equally effective as the conventional FFRD in treatment of Class II malocclusion with dento-alveolar changes and additional maxillary restricting effect. It has an additional advantage of immediate initiation of the Class II correction.

NuMA1 facilitates the assembly of the axon initial segment by promoting the retention of neurofascin-186.

Axon initial segment (AIS) functionality relies on a specific organization of the AIS with high enrichment of structural and functional proteins. In this issue, Torii et al. (2019. J. Cell. Biol.https://doi.org/10.1083/jcb.201907048) describe a mechanism for achieving a high density of proteins in the nascent AIS.

Complications encountered during Forsus Fatigue Resistant Device therapy.

INTRODUCTION: Fixed functional appliances are non-compliant solutions to Class II malocclusion treatment. The clinician, however, should be careful of unexpected complications during the therapy. METHODS: 58 female adolescents who presented with Class II malocclusion due to deficient mandible were treated with Forsus Fatigue Resistant Device (FFRD) therapy until an overcorrection to an edge to edge incisor relationship was achieved. RESULTS: Incisor relationship and overjet were corrected successfully in all the subjects. Twenty-two patients had a complications-free treatment, while several complications were encountered with the remaining 36 subjects. In particular, mandibular canine rotation and development of posterior crossbites were the most common complications, with percentages of 51.7% and 25.9% respectively. Other complications included the breakage and shearing of the extraoral tubes of the first molar bands, and excessive intrusion of the upper first molars. CONCLUSIONS: FFRD is an efficient appliance for treatment of Class II malocclusion; however, different complications were encountered during the appliance therapy. A focus on taking precautions and applying preventive measures can help to avoid such problems, reducing the number of emergency appointments and enhancing the treatment experience with the appliance.

Force magnitude as a variable in maxillary buccal segment intrusion in adult patients with skeletal open bite.

OBJECTIVES: To compare the effects of two different force magnitudes on maxillary posterior segment intrusion using mini-screws. The null hypothesis was that there would be no difference between the two force magnitudes. MATERIALS AND METHODS: Adult patients with skeletal open bite and a dental open bite ranging from 3 to 8 mm were recruited for this trial. The comparator group had 200 g of intrusive force applied for posterior segment intrusion, whereas 400 g of force was applied in the intervention group. Primary outcomes were the amount of posterior teeth intrusion and anterior open bite closure. RESULTS: Twenty-two subjects were randomized to include 11 participants in each group. One participant dropped out in each group, leaving us with 10 subjects to be analyzed per group. There was statistically significant posterior teeth intrusion of 2.42 ± 2.06 and 2.26 ± 1.87 mm for the comparator and intervention groups, respectively, with no difference between them. Statistically significant open bite closure was achieved in both groups, measuring 2.24 ± 1.18 and 3.15 ± 1.06 mm in the comparator and intervention groups, respectively, with no difference between them. CONCLUSIONS: Both the 200 g and 400 g intrusive forces yielded similar outcomes in terms of posterior teeth intrusion and anterior open bite closure.

Tropomyosin Tpm3.1 Is Required to Maintain the Structure and Function of the Axon Initial Segment.

The axon initial segment (AIS) is the site of action potential initiation and serves as a cargo transport filter and diffusion barrier that helps maintain neuronal polarity. The AIS actin cytoskeleton comprises actin patches and periodic sub-membranous actin rings. We demonstrate that tropomyosin isoform Tpm3.1 co-localizes with actin patches and that the inhibition of Tpm3.1 led to a reduction in the density of actin patches. Furthermore, Tpm3.1 showed a periodic distribution similar to sub-membranous actin rings but Tpm3.1 was only partially congruent with sub-membranous actin rings. Nevertheless, the inhibition of Tpm3.1 affected the uniformity of the periodicity of actin rings. Furthermore, Tpm3.1 inhibition led to reduced accumulation of AIS structural and functional proteins, disruption in sorting somatodendritic and axonal proteins, and a reduction in firing frequency. These results show that Tpm3.1 is necessary for the structural and functional maintenance of the AIS.

Evaluation of the miniplate-anchored Forsus Fatigue Resistant Device in skeletal Class II growing subjects: A randomized controlled trial.

OBJECTIVES: To evaluate the use of direct miniplate anchorage in conjunction with the Forsus Fatigue Resistant Device (FFRD) in treatment of skeletal Class II malocclusion. MATERIALS AND METHODS: Forty-eight females with skeletal Class II were randomly allocated to the Forsus plus miniplates (FMP) group (16 patients, age 12.5 ± 0.9 years), Forsus alone (FFRD; 16 patients, age 12.1 ± 0.9 years), or the untreated control group (16 subjects, age 12.1 ± 0.9 years). After leveling and alignment, miniplates were inserted in the mandibular symphysis in the FMP group. The FFRD was inserted directly on the miniplates in the FMP group and onto the mandibular archwires in the FFRD group. The appliances were removed after reaching an edge-to-edge incisor relationship. RESULTS: Data from 46 subjects were analyzed. The effective mandibular length significantly increased in the FMP group only (4.05 ± 0.78). The mandibular incisors showed a significant proclination in the FFRD group (9.17 ± 2.42) and a nonsignificant retroclination in the FMP group (-1.49 ± 4.70). The failure rate of the miniplates was reported to be 13.3%. CONCLUSIONS: The use of miniplates with the FFRD was successful in increasing the effective mandibular length in Class II malocclusion subjects in the short term. The miniplate-anchored FFRD eliminated the unfavorable mandibular incisor proclination in contrast to the conventional FFRD.

ASD-Associated De Novo Mutations in Five Actin Regulators Show Both Shared and Distinct Defects in Dendritic Spines and Inhibitory Synapses in Cultured Hippocampal Neurons.

Many actin cytoskeleton-regulating proteins control dendritic spine morphology and density, which are cellular features often altered in autism spectrum disorder (ASD). Recent studies using animal models show that autism-related behavior can be rescued by either manipulating actin regulators or by reversing dendritic spine density or morphology. Based on these studies, the actin cytoskeleton is a potential target pathway for developing new ASD treatments. Thus, it is important to understand how different ASD-associated actin regulators contribute to the regulation of dendritic spines and how ASD-associated mutations modulate this regulation. For this study, we selected five genes encoding different actin-regulating proteins and induced ASD-associated de novo missense mutations in these proteins. We assessed the functionality of the wild-type and mutated proteins by analyzing their subcellular localization, and by analyzing the dendritic spine phenotypes induced by the expression of these proteins. As the imbalance between excitation and inhibition has been suggested to have a central role in ASD, we additionally evaluated the density, size and subcellular localization of inhibitory synapses. Common for all the proteins studied was the enrichment in dendritic spines. ASD-associated mutations induced changes in the localization of α-actinin-4, which localized less to dendritic spines, and for SWAP-70 and SrGAP3, which localized more to dendritic spines. Among the wild-type proteins studied, only α-actinin-4 expression caused a significant change in dendritic spine morphology by increasing the mushroom spine density and decreasing thin spine density. We hypothesized that mutations associated with ASD shift dendritic spine morphology from mushroom to thin spines. An M554V mutation in α-actinin-4 (ACTN4) resulted in the expected shift in dendritic spine morphology by increasing the density of thin spines. In addition, we observed a trend toward higher thin spine density with mutations in myosin IXb and SWAP-70. Myosin IIb and myosin IXb expression increased the proportion of inhibitory synapses in spines. The expression of mutated myosin IIb (Y265C), SrGAP3 (E469K), and SWAP-70 (L544F) induced variable changes in inhibitory synapses.

Are self-ligating brackets' slots dimensions accurate?

OBJECTIVE: The purpose of this study is to measure the dimensions of the slot's top and base of passive self-ligating brackets of three commercial and available systems and to compare the measured dimensions with the manufacturers' published dimensions. METHODS: Digital microscope was used to measure the slot's top and base of 40 Central incisor brackets by three different manufacturers, Carriere SLX (Ortho Organizer, USA), Damon Q (Oramco USA) and Smart Clip (3M Unitek USA). The measurements were taken after the doors of all brackets were removed and compared with the manufacturers' claimed dimensions. RESULTS: All brackets showed a significant increase in dimensions from both the slot's top and base compared to the manufacturers' published dimensions. For the base of the bracket's slot, Carriere SLX brackets showed the least difference while Damon Q brackets had the greatest. Moreover, for the top of the bracket's slot, the Smart clip brackets showed the greatest difference. The percentage of difference between the actual measurements and the manufacturers' prescriptions shows that for the slot's base, Carriere SLX brackets had the smallest percentage increase by .36%, followed by Smart clip by 6.7% and the Damon Q brackets by 8.1%. While for the slot's top Carriere SLX had the smallest percentage increase by .72%, followed by Damon Q by 12.3% increase and finally Smart Clip brackets by 12.8%. CONCLUSIONS: The actual measurements of passive self-ligating brackets from 3 manufacturers were larger than the manufacturers' published dimension. This amount of increase may affect the amount torque expression.

Three-dimensional effects of the mini-implant-anchored Forsus Fatigue Resistant Device: A randomized controlled trial.

OBJECTIVE: To detect three-dimensionally the effects of using mini-implant anchorage with the Forsus Fatigue Resistant Device (FFRD). MATERIALS AND METHODS: The sample comprised 43 skeletal Class II females with deficient mandibles. They were randomly allocated into three groups: 16 patients (13.25 ± 1.12 years) received FFRD alone (Forsus group), 15 subjects (13.07 ± 1.41 years) received FFRD and mini-implants (FMI group), and 12 subjects (12.71 ± 1.44 years) were in the untreated control group. Three-dimensional analyses of cone beam computed tomographic images were completed, and the data were statistically analyzed. RESULTS: Class I relationship and overjet correction were achieved in 88% of the cases. None of the two treatment groups showed significant mandibular skeletal effects. In the FMI group, significant headgear effect, decrease in maxillary width, and increase in the lower facial height were noted. In the FMI group, retroclination of maxillary incisors and distalization of maxillary molars were significantly higher. Proclination and intrusion of mandibular incisors were significantly greater in the Forsus group. CONCLUSIONS: FFRD resulted in Class II correction mainly through dentoalveolar effects and with minimal skeletal effects. Utilization of mini-implant anchorage effectively reduced the unfavorable proclination and intrusion of mandibular incisors but did not produce additional skeletal effects.

Complications encountered during Forsus Fatigue Resistant Device therapy

ABSTRACT Introduction: Fixed functional appliances are non-compliant solutions to Class II malocclusion treatment. The clinician, however, should be careful of unexpected complications during the therapy. Methods: 58 female adolescents who presented with Class II malocclusion due to deficient mandible were treated with Forsus Fatigue Resistant Device (FFRD) therapy until an overcorrection to an edge to edge incisor relationship was achieved. Results: Incisor relationship and overjet were corrected successfully in all the subjects. Twenty-two patients had a complications-free treatment, while several complications were encountered with the remaining 36 subjects. In particular, mandibular canine rotation and development of posterior crossbites were the most common complications, with percentages of 51.7% and 25.9% respectively. Other complications included the breakage and shearing of the extraoral tubes of the first molar bands, and excessive intrusion of the upper first molars. Conclusions: FFRD is an efficient appliance for treatment of Class II malocclusion; however, different complications were encountered during the appliance therapy. A focus on taking precautions and applying preventive measures can help to avoid such problems, reducing the number of emergency appointments and enhancing the treatment experience with the appliance.

RESUMO Introdução: Os aparelhos funcionais fixos são uma solução para o tratamento da má oclusão de Classe II em pacientes não colaboradores. Porém, o ortodontista deve estar ciente das complicações inesperadas decorrentes do seu uso. Métodos: Cinquenta e oito pacientes adolescentes do sexo feminino com má oclusão de Classe II por deficiência mandibular foram tratadas com o aparelho Forsus FRD até se alcançar uma sobrecorreção, com relação de topo a topo dos incisivos. Resultados: A relação entre os incisivos e a sobressaliência foram corrigidas com sucesso em todas as pacientes. Vinte e duas pacientes não apresentaram complicações durante o tratamento, enquanto as demais trinta e seis pacientes apresentaram diferentes complicações. As complicações mais comuns foram a rotação do canino inferior e o desenvolvimento de mordida cruzada posterior, com prevalência de 51,7% e 25,9%, respectivamente. As demais complicações incluíram quebra e cisalhamento dos tubos extrabucais das bandas dos primeiros molares, e intrusão excessiva dos primeiros molares superiores. Conclusões: O FRD é um aparelho eficiente para o tratamento da má oclusão de Classe II. No entanto, diferentes complicações foram encontradas durante o uso desse aparelho. O foco na tomada de precauções e em medidas preventivas pode ajudar a evitar tais complicações, reduzindo o número de consultas de emergência e melhorando a experiência do paciente no tratamento com esse aparelho.