Estoy empezando a tratar pacientes en dentición mixta con ClasesIII. Utilizo un expansor (aunke no tenga mordida cruzada, pq tb abre las demás suturas maxilares y beneficia el uso de la máscara facial) el problema me surge al ajustar la máscara facial, se utiliza con una llave allen, pero parece que no le ajusta bien y ademas es complejo que no roce ninguna estructura de la cara.utilizais alguna en concreto??? y otra pregunta, los elasticos si los niños son menores de 10 años son 6onzas 3/8" por lado???gracias por todo.

Tiene que utilizar la máscara adecuada al caso, hay varios diseños, y buscar la herramienta que pueda accionar el tornillo de cabeza allen, que es muy preciso. Las diferentes máscaras tienen siempre un apoyo frontal y otro en el mentón.
Sirven solo si el diagnóstico indica una falta de desarrollo del maxilar superior.
El prognatismo verdadero, por crecimiento mandibular, no se puede manejar con la máscara, y lleva siempre a una solución quirúrgica.
La fuerza a aplicar la da el criterio clínico del operador, conforme al paciente.
En los tratamientos de salud, no hay recetas de cocina, y los márgenes que se indican son los que experimental y estadisticamente muestran una acción, sin perjuicio de lo que pueda hacer el operador clínico.

Según mi experiencia personal y en base a los casos tratados por mí mismo y en base a los numerosos casos, unos dirigidos por mí y otros por profesores del Máster, tratados por los residentes de diferentes promociones, la máscara facial para tracción anterior del maxilar previa disyunción palatina es un buen método para casos en los que la causa de la clase III sea fundamentalmente maxilar y la mandíbula esté anterorrotada (braqui) y nos venga bien que el apoyo de la máscara en el mentón consiga camuflar la clase III posterorrotando la mandíbula.
La máscara, por otra parte es muy latosa para ajustar y muy incómoda para llevar.

Cuando la causa de la clase III es fundamentalmente mandibular y en pacientes con la mandíbula ya posterorrotada, la máscara estaría CONTRAINDICADA, desde mi punto de vista.
La elección sería la MENTONERA CON VÁSTAGOS para tracción anterior. Usandola adecuadamente frena el crecimiento mandibular y no posterorrota o posterorrota menos. Y aunque no es cómoda de llevar, si lo es más que la máscara y es MUCHO MÁS ESTABLE.

En el foro hay temas abiertos sobre este debate.

__________________
Prof. JC Rivero Lesmes
http://www.ortodonciarivero.com

FRENA EL CRECIMIENTO MANDIBULAR?.... MMMM

Juanki: En lugar de ponerlo todo en duda, podrías aportar datos u opiniones fundamentadas para argumentar hipótesis, ideas o experiencias clínicas.

Tu actitud si que FRENA EL AVANCE Y EL CRECIMIENTO DE LA HUMANIDAD y DE LA PROFESIÓN.

Respetuosamente

__________________
Prof. JC Rivero Lesmes
http://www.ortodonciarivero.com

Teoricamente la mentonera con la presion inhibe el crecimiento de la capa precondroblastica del condilo mandibular, por tanto le impide crecer hacia atras-arriba, .........aunque esto esta en discusion, algunos autores apoyan que esto funciona y otros por el contrario lo rechazan de plano.

hombre la verdad es que como metodo ortopedico toda estructura que es limitada fisicamente no crece..............veamos el ejemplo de muchas cosas ( es como los zapatos de las mujeres de loto).
Por tanto no entiendo los autores que rechazan la mentonera, o no creen en ella............es que esto no es cuestion de fe, o funciona o no.

Esta claro que en algunos casos esta contraindicada y en otros no es capaz de cumplir su funcion como tal...........pero nunca rechazarla ni cuestionarla de plano.

Es mi humilde opinion

Suponiendo que la mentonera tenga esos efectos, que no los discuto, ¿el paciente utiliza la mentonera las 24 horas, incluso para comer y lavarse los dientes? ¿que ocurre las horas del dia que el paciente no lleva puesta la mentonera?

__________________
Manuel Roman Jimenez

www.ortodonciamalaga.com
www.avilesyroman.com

Bueno sigo bastante extrañando con sus respuestas Sr. Rivero. por que le incomoda que cuestionemos para tratar de enriquecer los foros? le repito otra vez NO ES MI INTENCION HERIR SUS CONOCIMIENTOS ni los de nadie... desde mi punto de vista deberíamos preguntar ante todo POR QUE? no le parecería que esto enriquecería mas los puntos de vista de las personas? ante este foro podría decirle que me parece un poco pobre el tema entre ortodoncistas sobre la efectividad de las MENTONERAS en la inhibición del crecimiento mandíbular ESTO YA TIENE BASTANTE INFORMACION como para tratar de cambiar la evidencia pero lo invito a que consulte grandes bases de datos como MEDLINE o algo que se le parezca.
ACLARO QUE MI RESPUESTA NO TRATA DE SER OFENSIVA...
Por que?... NO LO SE

hola a todos, este tema ya lo habiamos discutido el Dr. Rivero y yo en otro foro. Yo creo que desde ninguna punto de vista se debe tratar una clase III que no sea por retrusion maxilar con una mascara de protraccion. Indudablemente el mismo nombre del aparato los dice: tracciona del maxilar, asi que nunca cuando se trate de prognatismo puro, debieramos pensar en una mascara de protraccion, aunque si bien es cierto, de alguna manera actua sobre la mandibula haciendola crecer en un sentido mas dolico. Por otro lado el uso de la mentonera se da unicamente cuando el paciente es cl III por verdadero pronatismo y en braquifaciales, sin embargo, no es que la mandibula no crezca, lo que se hace es modificar el crecimiento abriendo el angulo goniaco. Es como los de los pies flor de loto, no es ue no crecen, se deforman.

__________________
Chío

Respetado juank:

Me sorprende que tras varios meses de silencio, vuelva a la ofensiva sobre un tema que efectivamente ha sido y seguirá siendo muy controvertido y que, por ello, ha sido tratado en otros apartados de este foro.
No creo que nadie pueda calificar con seguridad absoluta a ningún caso de clase III ósea como de puramente de causa maxilar o de puramente de causa mandibular. Pienso que la mayoría de los casos son, en mayor o menor medida, MIXTOS.
De cualquier forma, se trata de intentar conseguir los mejores resultados clínicos para el beneficio de nuestros pacientes, en cuanto a la función, a la normalización de la oclusión dentoalveolar y si es posible esquelética, y que esos resultados sean estables en el tiempo.

Es cierto que muchos resultados son compensatorios por la posterorrotación mandibular, que sobretodo produce la máscara y la mentonera también, si no se utiliza adecuadamente. Pero en los casos braquifaciales este efecto es deseable, no siendo así en los dólicos.

En los casos mixtos, que son casi todos, la tracción anterior del maxilar, tras la disyunción rápida, sumada a la acción ortopédica de la mentonera correctamente usada, con una biomecánica que haga pasar el vector final de la fuerza que vaya desde el mentón hacia el occipital, pasando por encima de los cóndilos, se consiguen efectos de disminución del ángulo goniaco y por tanto disminución efectiva de la mandíbula y una protracción del maxilar.
En definitiva, una corrección de la maloclusión, que es lo que nos preocupa, en muchos casos de clase III con patrón dolicofacial, donde no nos podemos permitir el posterorrotar el plano oclusal ni el mandibular.

A continuación le envío algunos abstract de los muchos que se pueden encontrar en la literatura científica que avalan lo que acabo de decir.

Saludos cordiales......Prof. Dr. J.C. Rivero Lesmes

1: FRANCISCO FERRE CABRERO
Acciones de la mentonera en clase III entre 5 y 10 años, con seguridad de su utilización.
Ortodoncia Española, 31: 123-146 (1990)

2: Angle Orthod. 2005 Jul;75(4):568-75. Links
Magnetic resonance imaging of the condylar growth pattern and disk position after chin cup therapy: a preliminary study.
Gökalp H, Kurt G.
Department of Orthodontics, School of Dentistry, Ankara University, Ankara, Turkey. haticegokalp@yahoo.com
This study was conducted on lateral cephalograms and magnetic resonance images (MRIs) obtained from 20 subjects with Class III malocclusion. Only clinically temporomandibular joint (TMJ) symptom-free subjects were included in this study. In the treatment group, a chin cup with 600 g of force was applied in 13 patients (10 girls and three boys) with a mean age of nine years. The chin cup was applied in a direction from the chin toward the TMJ. The control group consisted of seven patients (six girls and one boy) with a mean age of eight year nine months. Orthodontic treatment was not applied in the control group. Records were taken at the beginning and end of chin cup therapy from all the subjects. Measurements were made on lateral cephalograms and unilateral-left sagittal-oblique TMJ MRIs. Variables obtained at the beginning and end of the study were compared by Student's t-tests and paired t-tests. Relationships between craniofacial and TMJ variables were analyzed by correlation analysis. The mandibular corpus length was increased and condylar head angle was decreased by chin cup therapy. A positive correlation existed between activation of sagittal maxillary and mandibular growth and bending of the condylar head. This study showed that the condylar growth pattern was altered by chin cup. It may be implied that the source of improvement is adaptation of the craniofacial structures to the changes of the condylar growth pattern produced by the chin cup.

3: World J Orthod. 2006 Fall;7(3):236-53. Links
Redirecting the growth pattern with rapid maxillary expander and chin cup treatment: changing breathing pattern from oral to nasal.
Chung JC.
shiucchen@yahoo.com
AIM: This study was undertaken to assess the possibility of redirecting the growth pattern by using rapid maxillary expansion and a light-force chin cup for a short period of time, with limited patient cooperation, during the pre-growth and growth-spurt stages. METHODS: The study included a series of 60 patients, 24 males and 36 females from 7 to 14 years of age, with crossbite or midfacial deficiencies. Treatment involved wearing a chin cup 24 hours a day to force mouth closure during rapid maxillary expansion activation, which was 2 turns per day to rapidly expand the midpalatal suture and enhance nasal breathing. Lateral cephalograms and intraoral and facial photographs were taken 2 years before treatment, at the time of rapid maxillary expansion, 3 weeks following rapid maxillary expansion activation, 3 months after the cessation of rapid maxillary expansion activation, and 1 to 3 years post-rapid maxillary expansion activation. RESULTS: Despite the severity, the crossbite would always improve within 21 days following rapid maxillary expansion activation. The cephalograms and photographs demonstrated forward movement of the nasal bridge and maxilla, with backward rotation of the mandible. The bite depth remained nearly the same as pretreatment. CONCLUSION: The results suggested that 24 hours of light-force chin cup wear, while expanding the midpalatal suture, is the major factor to force mouth closure and enhance nasal breathing. As a result, there is advancement of the maxilla, avoidance of tongue encroachment upon the mandible, and deceleration of horizontal mandibular growth.


4: Pediatr Dent. 1997 Sep-Oct;19(6):386-95. Links
Treatment of Class III problems begins with differential diagnosis of anterior crossbites.
Ngan P, Hu AM, Fields HW Jr.
Department of Orthodontics, West Virginia University, School of Dentistry, USA.
Etiology of Class III malocclusion can be genetic or environmental. Proclination of mandibular incisors and retroclination of maxillary incisors can cause posturing of the mandible in an anterior position due to incisal interference, a condition called pseudo Class III malocclusion that can be misleading in evaluating a patient with skeletal Class III malocclusion. Unfortunately, cephalometric evaluation may not be the most reliable tool in differentiating whether the maxilla or the mandible contributes to the skeletal disharmony. The most consistent findings seem to be the dental characteristics of Angle's Class III molars and canines, retroclined mandibular incisors, and the presence of an edge-to-edge or an anterior crossbite occlusion. This paper presents a diagnostic scheme to differentiate between dental and skeletal crossbites. Early treatment of Class III malocclusion can help to minimize the adaptations and limitations that are often seen in severe malocclusion of the late adolescence. However, treatment of skeletal crossbites remains a continuous challenge to the profession. Due to the diversity and variability in facial growth, accurate individualized growth prediction is not possible at the moment. Treatment directed at the mandible seems to invite relapse during the pubertal growth period. Treatment directed at the maxilla shows promising results and is awaiting long-term clinical results following early orthopedic interventions. Several intraoral appliances have proved to be successful in eliminating dental crossbites.

5: J Oral Rehabil. 2005 Oct;32(10):720-8. Links
Geometric morphometric assessment of treatment effects of maxillary protraction combined with chin cup appliance on the maxillofacial complex.
Chang HP, Lin HC, Liu PH, Chang CH.
Department of Orthodontics and Graduate Institute of Dental Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan. hopoch@kmu.edu.tw
The aim of this study was to investigate the treatment effects on the maxillofacial complex by maxillary protraction combined with chin cup therapy among growing children. An effective geometric morphometric assessment of cephalometric radiographs, using Procrustes analysis and thin-plate spline analysis, was applied to evaluate shape change in the craniofacial and midfacial configurations of a treated sample of 20 children with skeletal Class III malocclusion. This was compared with matched untreated skeletal Class III controls. Marked treatment induced change involved the maxilla and the mandible. Major deformation consisted of forward advancement of the maxillary complex with negligible rotation of the palatal plane and a forward direction of growth of the mandibular condyle associated with a restriction in sagittal advancement of the chin. Considerable dentoalveolar components contributed to the correction of anterior crossbite. Further detailed study of skeletofacial remodelling in response to maxillary protraction in other skeletal components, including the cranial base and the mandibular complex that contribute to Class III skeletal discrepancies, is warranted.

6: J Formos Med Assoc. 2007 May;106(5):380-91. Links
Treatment effects of occipitomental anchorage appliance of maxillary protraction combined with chincup traction in children with Class III malocclusion.
Lin HC, Chang HP, Chang HF.
Department of Orthodontics, Taipei Medical University Hospital and School of Dentistry, Taipei Medical University, Taipei, Taiwan.
BACKGROUND/PURPOSE: Little information related to the treatment effects of the occipitomental anchorage (OMA) appliance of maxillary (Mx) protraction combined with chincup traction is available. The aim of this study was to investigate the treatment effects of the OMA orthopedic appliance on patients with Class III malocclusion. METHODS: Pretreatment and post-treatment cephalometric records of 20 consecutively treated patients with Class III malocclusions were evaluated and compared with a matched sample of untreated Class III control subjects. RESULTS: The OMA appliance is effective for correcting skeletal Class III malocclusion in growing children. The treatment effects of this orthopedic appliance were considered to be from both skeletal and dentoalveolar changes. The skeletal effects were mainly obtained by stimulating forward growth of the Mx complex with negligible rotation of the Mx plane and restraining forward advancement of the mandible (Mn) with backward and downward rotation of the Mn plane. The observed dentoalveolar effects were mostly due to the labial tipping movement of the Mx incisors. CONCLUSION: Our results suggest that the OMA orthopedic appliance can correct the mesial jaw relationship and negative incisal over jet. This appliance is effective for correcting skeletal Class III malocclusion with both midface deficiency and Mn prognathism in growing children.

7: Angle Orthod. 1999 Dec;69(6):543-52. Links
Maxillary protraction and chincap appliance treatment effects and long-term changes in skeletal class III patients.
Yoshida I, Ishii H, Yamaguchi N, Mizoguchi I.
Department of Orthodontics, School of Dentistry, Health Sciences University of Hokkaido, Japan. yoshida@hoku-iryo-u.ac.jp
The purpose of this study was to investigate the orthopedic effects of combined maxillary protraction appliance (MPA) and chincap therapy on growing Japanese girls and the posttreatment changes after growth is complete. To estimate the actual effects of treatment and posttreatment changes, we used a series of templates that had been constructed from semilongitudinal data of Japanese girls with normal occlusion. During treatment, forward movement of the maxilla with counterclockwise rotation, and backward and downward movement of the mandible with clockwise rotation and growth retardation were observed. The forward movement of the maxilla persisted until growth was complete. During the posttreatment period, the mandible maintained its improved position but showed excessive growth, which could be a rebound change. These results indicate that combined MPA and chincap treatment is effective for correcting skeletal Class III malocclusion.

8: Angle Orthod. 2005 Jul;75(4):576-83. Links
Chin cup treatment outcomes in skeletal Class III dolicho- versus nondolichofacial patients.
Iida Y, Deguchi ST, Kageyama T.
Unit of Orthodontics, Division of Hard Tissue Research, Graduate School, Matsumoto Dental University, Nagano-ken, Japan.
This study examines cephalometric differences and sex differences in the long-term outcome of chin cup treatments of Class III subjects with two facial patterns. Seventeen nondolichofacial and 16 dolichofacial Class III male patients and 16 nondolichofacial and 16 dolichofacial female patients were treated by either bicuspid extraction or nonextraction. Rapid palatal expansion without maxillary protraction was performed on 11 male cases and 15 female cases. The borderline between the two groups was drawn either at 39 degrees mandibular plane angle or 132 degrees (male subjects) or 130 degrees (female subjects) gonial angle. Dolichofacial subjects were treated with either an occipital or a high-pull chin cup force during the first two years, followed by high-pull force during night-time wear for the subsequent three years. All treated cases showed excellent results in the retention records with acceptable posterior occlusion as well as excellent skeletal and soft-tissue profiles. In addition, patient compliance was excellent. The treatment outcomes of the two groups showed significant improvement of the skeletal Class III malocclusion. This study indicated that the treatment period and wear time of the chin cup appliance in nondolichofacial (mostly mesiofacial pattern) patients could be shorter than those of dolichofacial patients. Although all subjects showed significant improvement in the Class III malocclusion, the treatment outcome in the two groups maintained the original characteristic skeletal morphology at retention.

9: Angle Orthod. 2005 Jul;75(4):568-75. Links
Magnetic resonance imaging of the condylar growth pattern and disk position after chin cup therapy: a preliminary study.
Gökalp H, Kurt G.
Department of Orthodontics, School of Dentistry, Ankara University, Ankara, Turkey. haticegokalp@yahoo.com
This study was conducted on lateral cephalograms and magnetic resonance images (MRIs) obtained from 20 subjects with Class III malocclusion. Only clinically temporomandibular joint (TMJ) symptom-free subjects were included in this study. In the treatment group, a chin cup with 600 g of force was applied in 13 patients (10 girls and three boys) with a mean age of nine years. The chin cup was applied in a direction from the chin toward the TMJ. The control group consisted of seven patients (six girls and one boy) with a mean age of eight year nine months. Orthodontic treatment was not applied in the control group. Records were taken at the beginning and end of chin cup therapy from all the subjects. Measurements were made on lateral cephalograms and unilateral-left sagittal-oblique TMJ MRIs. Variables obtained at the beginning and end of the study were compared by Student's t-tests and paired t-tests. Relationships between craniofacial and TMJ variables were analyzed by correlation analysis. The mandibular corpus length was increased and condylar head angle was decreased by chin cup therapy. A positive correlation existed between activation of sagittal maxillary and mandibular growth and bending of the condylar head. This study showed that the condylar growth pattern was altered by chin cup. It may be implied that the source of improvement is adaptation of the craniofacial structures to the changes of the condylar growth pattern produced by the chin cup.
10: Angle Orthod. 1998 Oct;68(5):419-24. Links
Electromyographic investigation of chin cup therapy in Class III malocclusion.
Deguchi T, Iwahara K.
Department of Orthodontics, Matsumoto Dental College, Nagano-ken, Japan.
Electromyographic activity was evaluated in 20 patients (10 girls and 10 boys, mean age 10 years) with Class III malocclusion who were treated with a chin cup appliance. The posttreatment data were obtained at the end of phase 1 chin cup treatment when the anterior crossbite had been corrected. EMG activity of the masseter and temporal muscles for each subject were studied during unilateral chewing using the following parameters: mean cumulative voltage (MCV), mean maximum peak voltage (MMPV), and rotational direction of the differential lissajous EMG (DL-EMG). The ANB angle improved from -1.0 degree (mean) to 0 degree. The electromyographic study revealed a decrease in masseter muscle activity on both the working (chewing) and balancing sides, with no improvement in the coordination of bilateral masseter and anterior temporal muscles.

11: Angle Orthod. 1996;66(2):139-45. Links
Stability of changes associated with chin cup treatment.
Deguchi T, Kitsugi A.
Department of Orthodontics, Matsumoto Dental College, Nagano, Japan.
Twenty-four Japanese girls with anterior crossbite (Class III malocclusion) were selected for this study of the stability of changes associated with chin cup therapy. Pretreatment cephalometric measurements of the study sample were compared with those in a normal group. In addition, angular and linear measurements were also compared to assess the effectiveness of chin cup therapy in improving Class III skeletal components during the postretention period. The subjects showed characteristic values found in Class III malocclusion for SNB, ANB, and NPg to FH, and these values were significantly different from those in the normal group. The subjects who were past puberty showed more severe Class III skeletal patterns for ANB compared with the prepubertal subjects, and their initial Class III skeletal components showed more satisfactory improvement, including 2.0 degrees increase of SNA and 1.8 degrees increase of ANB during the postretention period.



12: Eur J Orthod. 1993 Dec;15(6):527-33. Links
Biomechanical changes of the mandible from orthopaedic chin cup force studied in a three-dimensional finite element model.
Tanne K, Lu YC, Tanaka E, Sakuda M.
Department of Orthodontics, Osaka University, Faculty of Dentistry, Japan.
Biomechanical changes of the mandible from orthopaedic chin cup forces were investigated by means of finite element analysis. A three-dimensional model of the mandible including the temporomandibular joint was developed for stress analysis in the mandible. A chin cup force of 400 gf was applied at pogonion on the mandible in the direction toward the condyle. From the stress analyses, it was revealed that (1) uniform tensile stresses were produced at the outer borders of the mandible, (2) compressive stresses were induced in the centre of the mandible, (3) compressive stresses were generated widely on the surface of the condyle, and (4) stresses on the condyle were smaller in magnitude than those in the mandibular corpus. These results coincide with morphological changes of the mandible revealed in previous studies and, thus, indicate an association of stresses with remodelling of the mandible from chin cup therapy applied to adolescent patients with mandibular prognathism.

__________________
Prof. JC Rivero Lesmes
http://www.ortodonciarivero.com