Abordaje terapéutico del colapso transversal del maxilar superior con microimplantes (TAD´s) / Therapeutic approach of transverse maxillary collapse with microimplants (TAD's)

Introducción. La atresia o estrechez del maxilar superior es una patología de origen multifactorial que genera un colapso transversal, el mismo e implica la carencia de espacio necesario para la disposición correcta de las piezas dentales. Objetivo. El presente artículo está enmarcado en una revisión narrativa de la literatura, con el objetivo de describir el abordaje terapéutico del colapso transversal del maxilar superior con microimplantes (TAD´s), determinando los efectos esqueléticos y dentoalveolares en el maxilar superior, así como las ventajas y desventajas del tratamiento. Método. La búsqueda de artículos se realizó a través de mediante las plataformas de: Scielo, PubMed, Google Académico y Medline. Se seleccionaron 21 artículos cuyos textos completos fueron descargados para examinarlos a detalle y verificar que cumplieran con todos los criterios de inclusión, de los cuales se obtuvieron 16 artículos para elaborar esta revisión narrativa. Conclusiones. El abordaje terapéutico del colapso transversal se produce por medio de la expansión rápida del maxilar (ERM) o disyunción maxilar, en pacientes jóvenes en crecimiento; y en los pacientes adultos se suele emplear un tratamiento con técnica MARPE con microimplantes (TAD´s). El principal efecto esquelético es la apertura de la sutura maxilar que varía de 2 a 10 mm, muchos autores coinciden en que el manejo del colapso transversal del maxilar superior con microimplantes no genera efectos dentoalveolares negativos, al contrario, tiene ventajas biomecánicas debido al anclaje con el hueso, reduciendo el riesgo de movimiento dentales indeseados y permitiendo un control del crecimiento vertical.

Introduction. The atresia or narrowness of the upper jaw is a pathology of multifactorial origin that generates a transverse collapse, it implies the lack of space necessary for the correct arrangement of the dental pieces. Objective. This article is framed in a narrative review of the literature, with the aim of describing the therapeutic approach of transverse maxillary collapse with microimplants (TAD's), determining the skeletal and dentoalveolar effects in the maxilla, as well as the advantages and disadvantages of treatment. Method. The search for articles was carried out through the following platforms: Scielo, PubMed, Google Scholar and Medline. 21 articles whose full texts were downloaded were selected to examine them in detail and verify that they met all the inclusion criteria, of which 18 articles were obtained to prepare this narrative review. Conclusions. The therapeutic approach to transverse collapse occurs through rapid maxillary expansion (RME) or maxillary disjunction, in young growing patients; and in adult patients, treatment with the MARPE technique with microimplants (TAD's) is usually used. The main skeletal effect is the opening of the maxillary suture, which varies from 2 to 10 mm. Many authors agree that the management of the transverse collapse of the maxilla with microimplants does not generate negative dentoalveolar effects, on the contrary, it has biomechanical advantages due to the anchorage with the bone, reducing the risk of unwanted dental movement and allowing control of vertical growth.

Recent advances in the spatial organization of the mammalian genome

The mammalian genome is complex and presents a dynamic structural organization that reflects function.Organization of the genome inside the mammalian nucleus impacts all nuclear processes including but notlimited to transcription, replication and repair, and in many biological contexts such as early development,differentiation and physiological adaptations. However, there is limited understating of how 3D organization ofthe mammalian genome regulates different nuclear processes. Recent advances in microscopy and a myriad ofgenomics methods—propelled by next-generation sequencing—have advanced our knowledge of genomeorganization to a great extent. In this review, we discuss nuclear compartments in general and recent advancesin the understanding of how mammalian genome is organized in these compartments with an emphasis ondynamics at the nuclear periphery

Fracture strength of orthodontic mini-implants

ABSTRACT Objective: This study aimed at evaluating the design and dimensions of five different brands of orthodontic mini-implants, as well as their influence on torsional fracture strength. Methods: Fifty mini-implants were divided into five groups corresponding to different manufactures (DEN, RMO, CON, NEO, SIN). Twenty-five mini-implants were subjected to fracture test by torsion in the neck and the tip, through arbors attached to a Universal Mechanical Testing Machine. The other 25 mini-implants were subjected to insertion torque test into blocks of pork ribs using a torquimeter and contra-angle handpiece mounted in a surgical motor. The shape of the active tip of the mini-implants was evaluated under microscopy. The non-parametric Friedman test and Snedecor's F in analysis of variance (ANOVA) were used to evaluate the differences between groups. Results: The fracture torque of the neck ranged from 23.45 N.cm (DEN) to 34.82 N.cm (SIN), and of the tip ranged from 9.35 N.cm (CON) to 24.36 N.cm (NEO). Insertion torque values ranged from 6.6 N.cm (RMO) to 10.2 N.cm (NEO). The characteristics that most influenced the results were outer diameter, inner diameter, the ratio between internal and external diameters, and the existence of milling in the apical region of the mini-implant. Conclusions: The fracture torques were different for both the neck and the tip of the five types evaluated. NEO and SIN mini-implants showed the highest resistance to fracture of the neck and tip. The fracture torques of both tip and neck were higher than the torque required to insert mini-implants.

RESUMO Objetivo: o objetivo do presente estudo foi avaliar o desenho e as medidas de cinco marcas diferentes de mini-implantes ortodônticos, e sua influência na resistência à fratura em torção. Métodos: cinquenta mini-implantes foram divididos em cinco grupos, correspondentes a diferentes fabricantes (DEN, Dentaurum; RMO, Rocky Mountain Orthodontics; CON, Conexão; NEO, Neodent; SIN, Sistema de Implantes Nacional). Vinte e cinco mini-implantes foram submetidos ao teste de fratura por torção no pescoço e na ponta, com mandris fixados a uma máquina universal de testes mecânicos. Os outros 25 mini-implantes foram submetidos ao teste de torque de inserção em blocos de costelas suínas, utilizando-se um torquímetro e um contra-ângulo montado em motor cirúrgico. O formato da ponta ativa dos mini-implantes foi avaliado por microscopia. O teste não-paramétrico de Friedman e o teste F de Snedecor na análise de variância (ANOVA) foram utilizados para avaliar as diferenças entre os grupos. Resultados: o torque de fratura do pescoço variou de 23,45 N.cm (DEN) a 34,82 N.cm (SIN); e o da ponta, entre 9,35 N.cm (CON) e 24,36 N.cm (NEO). O valor do torque de inserção variou de 6,6 N.cm (RMO) a 10,2 N.cm (NEO). As características que mais influenciaram os resultados foram: diâmetro externo, diâmetro interno, razão entre o diâmetro interno e o externo, e a presença de fresagem na região apical do mini-implante. Conclusões: os torques de fratura foram diferentes entre os cinco tipos avaliados, tanto no pescoço quanto na ponta. Os mini-implantes NEO e SIN foram os mais resistentes à fratura do pescoço e da ponta. Os torques de fratura tanto na ponta quanto no pescoço foram maiores do que o torque necessário para a inserção dos mini-implantes.

The effect of canine disimpaction performed with temporary anchorage devices (TADs) before comprehensive orthodontic treatment to avoid root resorption of adjacent teeth

ABSTRACT Objective: The aim of this study was to evaluate the movement of impacted canines away from the roots of neighboring teeth before full-mouth bracket placement, performed by means of TADs to decrease undesired side effects on adjacent teeth. Methods: The study sample consisted of 34 palatally impacted canines, being 19 in the experimental group and 15 in the control group. In the experimental group, before placement of brackets, the impacted canine was erupted by means of miniscrews. In the control group, after initiation of comprehensive orthodontics, canine disimpaction was performed by means of a cantilever spring soldered to a palatal bar. At the end of treatment, volume of lateral incisors and canine root resorption were measured and compared by means of a CBCT-derived tridimensional model. Visual Analogue Scale (VAS) score, bleeding on probing (BOP) and gingival index (GI) were recorded. Clinical success rate was also calculated. Results: The volume of root resorption of lateral teeth in the control group was significantly greater than in the experimental group (p < 0.001). At the end of treatment, VAS score, GI and BOP were not significantly different between the two groups. Conclusion: Based on our results, it seems that disimpaction of canines and moving them to the arch can be done successfully carried out with minimal side effects by means of skeletal anchorage.

RESUMO Objetivo: o objetivo do presente estudo foi avaliar o uso de dispositivos de ancoragem temporária (DATs) para a movimentação de caninos impactados, afastando-os das raízes dos dentes vizinhos, antes da colagem dos braquetes em todos os dentes, com o objetivo de minimizar os efeitos colaterais indesejáveis nesses dentes adjacentes. Métodos: a amostra consistiu de 34 caninos impactados por palatino, sendo 19 no grupo experimental e 15 no grupo controle. No grupo experimental, antes da colagem dos braquetes, os caninos impactados foram tracionados utilizando-se mini-implantes. No grupo controle, após o início do tratamento ortodôntico, a desimpacção dos caninos foi realizada com uma mola em cantiléver soldada a uma barra transpalatina. Ao fim do tratamento, os valores referentes à reabsorção radicular nos incisivos laterais e caninos foram medidos e comparados por meio de modelos tridimensionais reconstruídos a partir de TCFCs. Foram também registrados os escores relativos à dor sentida pelos pacientes, usando uma escala visual analógica (VAS); além do Índice de Sangramento à Sondagem (ISS) e do Índice Gengival (IG). O índice de sucesso clínico também foi calculado. Resultados: o volume de reabsorção radicular nos incisivos laterais no grupo controle foi significativamente maior do que no grupo experimental (p < 0,001). Ao fim do tratamento, não houve diferença significativa entre os dois grupos quanto aos escores relativos à VAS, ao IG e ISS. Conclusão: esses resultados sugerem que a desimpacção de caninos e a movimentação deles para a arcada dentária podem ser realizadas, com sucesso e com mínimos efeitos colaterais, por meio da ancoragem esquelética.

Evaluation of the palatal soft tissue thickness by cone-beam computed tomography / 대한치과교정학회지

OBJECTIVE: The purposes of this study were to measure the palatal soft tissue thickness at popular placement sites of temporary anchorage devices (TADs) by cone-beam computed tomography (CBCT) and evaluate the age, gender, and positional differences in this parameter. METHODS: The study sample consisted of 23 children (10 boys and 13 girls; mean age, 10.87 +/- 1.24 years; range, 6.7 to 12.6 years) and 27 adults (14 men and 13 women; mean age, 21.35 +/- 1.14 years; range, 20.0 to 23.8 years). Nine mediolateral and nine anteroposterior intersecting reference lines were drawn on CBCT scans of the 50 subjects, and the resultant measurement areas were designated according to their mediolateral (i.e., lateral, medial, and sutural) and anteroposterior (i.e., anterior, middle, and posterior) positions. Repeated-measures analysis of variance was performed to analyze intragroup and intergroup differences. RESULTS: No significant age and gender differences were found (p = 0.309 and 0.124, respectively). Further, no significant anteroposterior change was observed (p = 0.350). However, the lateral area presented the thickest soft tissue whereas the sutural area had the thinnest soft tissue (p < 0.001). CONCLUSIONS: Clinical selection of the placement sites of TADs should be guided by knowledge of the positional variations in the palatal soft tissue thickness in addition to other contributing factors of TAD stability.

Distalizador oseo-soportado sin minitornillos: c-dfd distalizer / Bone supported distalizer without miniscrews: C-DFD distalizer

La distalización es un tratamiento común en la corrección de las maloclusiones dentales clase II para lo cual se han diseñado aditamentos intraorales, como lo son el péndulo, el Dual Force Distalizer, entre otros. Estos aparatos han sido combinados con mini implantes temporales (TADs) para obtener máximo anclaje y así disminuir los efectos en la mesialización de premolares y vestibularización de incisivos superiores. Una modificación del dual forcé distalizer (DFD), Cortical – Dual Force Distalizer (C-DFD) es descrito en el presente artículo que consiste en la adición de barras puntiagudas en la parte anterior del aparato para evitar la necesidad de TADs como anclaje y eliminar el botón acrílico permiten una mejor higiene oral de la zona. La paciente tratada es una niña de 11 años, en estadio 3 de maduración cervical, con una maloclusión dental Clase ll , apiñamiento severo en el arco superior, canino superior derecho impactado, mordida profunda y un perfil no-favorable para el tratamiento con extracciones de premolares. El paciente recibió un distalizador óseo-soportado (C-DFD), hasta lograr una relación clase I y una resolución del apiñamiento. La aparatología fija fue utilizada para continuar con el tratamiento ortodóntico y el C-DFD se mantuvo pasivo como un aparato de anclaje durante la retracción de canino y premolar. Radiografías Cefálicas laterales y panorámicas fueron tomadas al principio y al final del movimiento para ver los cambios dentales y esqueléticos. La distalización fue lograda en 4.5 meses aproximadamente. Con un promedio de 4 mm por lado, con una resolución espontanea del apiñamiento anterior. No se observó ninguna pérdida de anclaje dental durante el movimiento distal, sugiriendo que esta modificación proporciona un anclaje absoluto.

Distalization is a common treatment in the correction of class II dental malocclusions for which several intraoral non-compliances appliances have been designed, such as the pendulum, Dual Force Distalizer, among others. This appliance has been combined with Mini-screws (TADs) to obtain maximum anchorage to decrease the side effects such as mesialization of premolars and labialization of upper incisors. A modification of the dual force distalizer (DFD), the cortical-DFD (C-DFD distalizer) is described in the present article that consisted in the inclusion of spikes in the anterior part of the appliance to avoid the need of TADs as anchorage and the acrylic button was eliminate for a better hygienic. The treated patient was a girl 11 years old, in stage 3 of the cervical vertebral maturation method, with a class ll dental malocclusion, severe crowding in the upper arch, upper right canine was impacted, deep bite and a non-favorable profile for premolar extraction treatment. The patient received a bone supported distalizer (C-DFD distalizer) until a super class l molar relationship was obtained and the crowding resolved. Fixed appliances was used to continue with the orthodontic treatment and the C-DFD was maintained passive as an anchorage device during the premolar and canine retraction. Lateral head plates and panoramic x-rays were taken at the beginning and at the end of the movement in order to see the dental and skeletal changes. It was found that the time of the distalization treatment was 4.5 months aprox. with an average distalization of 4 mm per side, with an spontaneously resolution of the anterior crowding. No loss of dental anchorage was observed during the distal movement, which shows that this modification provided absolute anchorage.