Estudio de la variación de la inclinación de la cabeza y la evolución de la dentición - Parte I: Dentición Primaria Completa y Mixta Primera Fase

Objetivo: estudiar y comparar la inclinación de la cabeza entre niños con dentición primaria completa y dentición mixta primera fase. Materiales y métodos: el estudio incluyó a 80 voluntarios entre 4 y 9 años, a quienes se les tomó una fotografía facial de perfil derecho estandarizada, en Posición Natural de Cabeza. Éstas fueron analizadas mediante software de edición de imágenes para determinar la inclinación de la cabeza de cada voluntario. Para ello, se definió un plano (plano t-ex) formado por el punto Intertrágico (t) y Exocanto (ex) y se comparó respecto a la horizontal verdadera. Los datos obtenidos fueron tabulados, clasificados en dos grupos según el tipo de dentición y analizados estadísticamente. Resultados: el promedio de inclinación del plano t-ex fue de 22,7º en el grupo de niños con dentición primaria completa y de 25,8º en el grupo de niños con dentición mixta primera fase. La diferencia entre ambos grupos fue de 3,1º, con significancia estadística (p = 0,006). Conclusión: la inclinación de la cabeza de los niños con dentición mixta primera fase es mayor en sentido antihorario, respecto a la de los niños con dentición primaria completa.

Objective: to study and compare head tilt among children with complete primary dentition and first transitional period of the mixed dentition stage. Materials and methods: the study included 80 volunteers between 4 and 9 years of age, who were taken a standardized right profile facial photograph in a Natural Head Position. These photographs were analyzed using image editing software to determine the head tilt of each volunteer. For this, a plane (plane t-ex) formed by the Intertragic point (t) and Exocanth (ex) was defined and compared with respect to the true horizontal. The data obtained were tabulated, classified into two groups according to the type of dentition and statistically analyzed. Results: the average t-ex plane inclination was 22.7º in the group of children with complete primary dentition and 25.8º in the group of children with first transitional period of the mixed dentition stage. The difference between both groups was 3.1º, with statistical significance (p = 0.006). Conclusion: the head tilt of children with first transitional period of the mixed dentition stage is greater in an anti-clockwise direction, compared to that of children with complete primary dentition.

Estudio de la variación de la inclinación de la cabeza y la evolución de la dentición - Parte III

El objetivo de esta investigación fue estudiar la variación de la Posición Natural de Cabeza (PNC) entre personas con dentición mixta segunda fase y dentición permanente, mediante fotogrametría facial. Para esto se realizó un estudio comparativo observacional analítico. La muestra estuvo conformada por 80 voluntarios divididos en dos grupos de 40 participantes cada uno. Se utilizó fotografías faciales de perfil estandarizadas en PNC. Mediante el software Photoshop® se trazó el plano Intertrágico-Exocanto (t-ex) y se midió el ángulo formado respecto a la horizontal verdadera para determinar la inclinación de la PNC. El valor de este ángulo se obtuvo mediante el software UTHSCSA ImageTool 3.0®. Los datos fueron tabulados en una planilla Excel (Microsoft® Excel® 2016) y analizados estadísticamente en el programa Stata 14 S/E®. Se observaron diferencias estadísticas en la inclinación de la PNC entre los grupos, con valores promedio 26.17° y 33.44° para dentición mixta segunda fase y permanente respectivamente, con una diferencia promedio de 7.27°. Se concluyó que la PNC de personas con dentición permanente presenta una rotación antihoraria respecto a personas con dentición mixta segunda fase.

This research aimed at studying the variation of the Natural Head Position (NHP) between people with second transitional mixed dentition and permanent dentition, using facial photogrammetry. For this, an analytical observational comparative study was performed. The sample consisted of 80 volunteers divided into two groups of 40 participants each. Using standardized profile facial photographs in NHP and Photoshop® software, the intertragic-exocanthion plane (t- ex) was traced. The angle formed to the true horizontal was measured to determine the inclination of the NHP using the UTHSCSA ImageTool 3.0® software. The data were tabulated in an Excel Spreadsheet (Microsoft® Excel® 2016) and analyzed with Stata 14 S/E® software. Statistical differences in the inclination of the NHP between groups were observed, with average values ​​of 26.17° for second transitional mixed dentition and 33.44° for permanent dentition, with an average difference of 7.27°. It was concluded that the NHP of people with permanent dentition shows an anti-clockwise rotation in relation to people with second transitional mixed dentition.

The effects of a series of posture intervention strategies guided by ultrasonography during labor process on the parturition with abnormal fetal head position / 中国实用护理杂志

Objective:To explore the clinical effects of a series of posture intervention strategies on correcting abnormal fetal position, so as to provide a basis for Clinical position management and promotion of natural delivery.Methods:This study was a randomized controlled trial. The convenience sampling method was used to select 196 full-term primiparas women with abnormal fetal orientation confirmed by ultrasound as single fetal head position in the Women′s Hospital, School of Medicine, Zhejiang University from March to October 2022 as the research objects. They were divided into control group 106 cases and research group 90 cases by random number table method. The control group received normal nursing and chose comfortable position by themselves during labor. The research group received a series of ultrasound-guided postural intervention strategies for postural management in the first and second stages of labor on the basis of normal nursing. The angle of progression and the midline angle, the fetal orientation, fetal orientation during complete uterine orifice and delivery outcome were compared between the two groups.Results:Finally, 190 cases were included, 105 cases in the control group and 85 cases in the research group. There were 76 vaginal deliveries in the research group and 95 in the control group. The rate of anterior occipital position and the angle of fetal head rotation in the research group were 73.68% (56/76) and 64.55 (37.90, 85.55)°, which were higher than 45.26% (43/95) and 33.00 (14.00, 60.00)° in the control group;the midline angle of the research group was 57.10(38.50, 75.80)°, which was lower than 80.00 (52.50, 90.30)° of the control group. There was significant difference between the two groups ( χ2 = 14.14, Z = 4.17, - 3.74, all P<0.01). The first stage of labor was 522.50 (413.00, 695.00) minutes and the total stage of labor was 611.00 (488.00, 812.00) minutes in the research group, which was lower than 620.00 (450.00, 795.00) and 700.00 (539.00, 904.00) minutes in the control group ( Z = - 2.34, - 2.03, both P<0.05). Conclusions:The application of the serial position intervention strategy under the ultrasound guidance during the labor process can improve the abnormal fetal position, shorten the first stage of labor time effectively and safely, while it does not have any significant effect on the improvement of the delivery outcome.

Estudio comparativo de la posición natural de cabeza entre las clases esqueléticas mediante fotogrametría facial

El objetivo de esta investigación es evaluar si existen diferencias en la inclinación de la Posición Natural de Cabeza (PNC) entre las clases esqueléticas, mediante fotogrametría. Para esto se realizó un estudio observacional analítico de corte transversal. La muestra fue de 45 voluntarios de entre 18 y 50 años. Se determinó la clase esquelética mediante análisis de Steiner y Wits, en radiografías laterales de cráneo, utilizando el software BlueSkyPlan®. A cada participante se le tomó una fotografía de perfil en PNC. Posteriormente, en Photoshop®, se trazó un plano entre los puntos tragion y exocanto (plano t-ex) y la horizontal verdadera, para finalmente medir el ángulo formado en el programa UTHSCSA ImageTool3.0®, determinando así la inclinación de la cabeza. Luego de tabular los datos, se realizaron análisis estadísticos. Este estudio evidenció una diferencia de 6,68° en promedio en la inclinación de la PNC entre los pacientes clase II y I esquelética, con significación estadística, por lo que se concluye que los pacientes clase II esquelética tienen una PNC más inclinada en sentido horario respecto a los pacientes clase I, en la muestra analizada. Los pacientes clase III no mostraron diferencias.

The objective of this research is to evaluate the differences in the inclination of the Natural Head Position (NHP) between skeletal classes, using photogrammetry. For this, a cross-sectional analytical observational study was carried out. The sample consisted of 45 volunteers between 18 and 50 years old. The skeletal class was determined by Steiner and Wits analysis, in lateral skull radiographs, using the BlueSkyPlan® software. Each participant had a profile photograph taken at NHP. A plane was drawn between the tragion and exocanthion points and the true horizontal using Photoshop®, and the angle was measured using UTHSCSA ImageTool3.0® software, assessing the inclination of the head. After data tabulation, statistical analyses were performed. This study showed an average difference of 6.68° in the inclination of the NHP between skeletal class II and I patients, with statistical significance. It was concluded that skeletal class II patients have a more inclined NHP in a clockwise direction compared to class I patients, in the analyzed sample. Class III patients did not show differences.

Protocolo fotográfico estandarizado para análisis facial en Posición Natural de Cabeza

RESUMEN: Introducción: La fotogrametría es el proceso por el que se obtienen medidas a partir de una fotografía. Para realizar una correcta toma fotográfica es de suma importancia estandarizar la técnica con el objetivo de obtener registros confiables y reproducibles. Uno de sus requisitos es definir la posición de la cabeza, ya que una postura incorrecta puede conducir a errores en el diagnóstico y planificación del tratamiento. Objetivo: Establecer un protocolo clínico para estandarizar registro fotográfico y posicionamiento del paciente para fotogrametría facial. Materiales y métodos: Se realizaron fotografías faciales estandarizadas a un total de 163 estudiantes. A 76 estudiantes se les realizaron mediciones faciales directas e indirectas. A 87 estudiantes se les comparó su Posición Natural de Cabeza en 3 momentos del día. Se compararon estadísticamente los resultados. Resultados: Al aplicar un protocolo estandarizado, no hubo diferencia estadística entre las medidas directas e indirectas ni al comparar la posición de la cabeza de cada estudiante. Conclusión: La estandarización del set fotográfico expuesto en este trabajo es válida para realizar registros fiables y útiles como examen complementario utilizando la Posición Natural de Cabeza, que permite mantener una posición confiable y estable en el tiempo.

ABSTRACT: Introduction: Photogrammetry is the process by which measurements are obtained from a photograph. To take a correct photographic shoot, it is very important to standardize the technique in order to obtain reliable and reproducible records. One of its requirements is to define the position of the head. Thus, an incorrect posture can lead to errors in diagnosis and treatment planning. Objective: Establish a clinical protocol to standardize photographic registration and patient positioning for facial photogrammetry. Materials and methods: Standardized facial photographs were taken to a total of 163 students. 76 students had direct and indirect facial measurements. 87 students had their Natural Head Position compared at 3 times of the day. The results were statistically compared. Results: When applying a standardized protocol, there was no statistical difference between direct and indirect measurements, nor when comparing the head position of each student. Conclusion: The standardization of the photographic set exposed in this work is valid for making reliable and useful records as a complementary examination using the Natural Head Position, which allows to maintain a reliable and stable position over time.

Posición Natural de Cabeza y su relación con el Plano de Frankfurt en cefalometría ortodóncica

RESUMEN: Objetivo: el objetivo de este estudio fue determinar la discrepancia del Plano de Frankfurt evaluado en fotogrametría y en cefalometría de radiografías laterales de cráneo respecto a la horizontal verdadera. Materiales y métodos: el estudio consideró a 34 voluntarios de la clínica del Postítulo de Ortodoncia y Ortopedia Dento Máxilo Facial de la Facultad de Odontología de la Universidad de Chile. Se utilizaron sus radiografías laterales de cráneo orientadas según el Plano de Frankfurt paralelo al piso y se les tomó una fotografía facial de perfil estandarizada en Posición Natural de Cabeza. Se trazó el Plano de Frankfurt y la Horizontal Verdadera en ambos exámenes y se midió el ángulo formado entre estos planos. Resultados: al comparar los ángulos mediante T-test, no hubo diferencia estadística. Conclusiones: mediante la aplicación de un protocolo sistematizado tanto para el registro fotográfico como para la obtención de la Posición Natural de Cabeza, se puede lograr que el Plano de Frankfurt sea prácticamente coincidente en radiografías laterales de cráneo y en fotografías clínicas, demostrando su uso hasta el día de hoy en la ortodoncia moderna.

ABSTRACT: Objective: the aim of this study was to determine the Frankfurt plane variation evaluated in photogrammetry and lateral skull x-ray cephalometry in relation to the true horizontal. Materials and methods: the study included 34 volunteers from the Universidad de Chile Dento-maxillofacial Orthodontics and Orthopedics Postgraduate Clinic. Their lateral skull radiographs, oriented according to the Frankfurt Plane parallel to the floor, were used and a standardized profile facial photograph was taken in Natural Head Position. The Frankfurt Plane and True Horizontal were drawn in both examinations and the angle formed between these planes was measured. Results: when comparing the angles through T-test, there was no statistical difference. Conclusions: through the application of a systematized protocol for both photographic record and natural head position obtained, the Frankfurt Plane can be practically coincident in lateral skull x-rays and clinical photographs, showing its usefulness up to the present days in modern orthodontics.

Effects of viscosity and head position on the surface electromyography of the suprahyoid muscles during swallowing / 中华物理医学与康复杂志

Objective:To explore the effect of swallowing fluids of different viscosities in different head positions on the surface electromyography (sEMG) of the suprahyoid muscles.Methods:Twenty healthy adults were asked to swallow 5ml of liquids with 5 different viscosities in 3 different head positions. sEMG signals were recorded from their suprahyoid muscles in real time. The interactions between viscosity, head position and suprahyoid muscle activation were determined using simple effect analysis.Results:Significant head position and viscosity effects were observed. In the head-turning-right or the right head-flexion position, the net amplitude values of the left suprahyoid muscles were significantly higher than those from the right side when swallowing fluid of the same viscosity. Meanwhile, the net amplitude values of the left suprahyoid muscles increased gradually and significantly from the neutral position to the head-turning-right and the right head-flexion positions. When swallowing fluid with a viscosity of 0 to 3, the net amplitude values of the right suprahyoid muscles in the right head-flexion position were significantly lower than in the neutral and right head-flexion positions. With a viscosity of 4 the values of the former were significantly higher than the latter. The net amplitude of the left superhyoid muscle group when swallowing zero-viscosity food in a head-turning-right position was significantly lower than that when swallowing food of viscosity 1 to 4. In the right head-flexion position, the net amplitude of the left superhyoid muscle group when swallowing zero-viscosity food was significantly lower than that when swallowing food of viscosity 2 to 4. When swallowing fluid of viscosity 1 it was also significantly lower than that when swallowing food of viscosity 3 to 4. In the same position, the net amplitude of the right suprhyoid muscle group when swallowing fluid of viscosity 4 was significantly higher than that with a viscosity of 0 to 1. At viscosity 3 it was significantly higher than with a viscosity of 1.Conclusion:Swallowing fluids of different viscosities in different head positions can affect the contraction of the suprahyoid muscles to different degrees.

La vertical verdadera al punto A´(blando), al Pg´(blando), al Labrale superior y al Labrale inferior en posición ideal asistida de la cabeza (PIAC) / The true vertical from point A´(soft), to Pg´ (soft), to superior Labrale and inferior Labrale in Ideal Assisted Head Position (PIAC)

El 81,3% de una encuesta realizada a 96 ortodoncistas y ortopedistas calificados y técnicos radiólogos consultados informan que ubican la cabeza del paciente en una posición ideal, subjetiva del profesional instruido que lo asiste, ya que muchas de sus fotografías y telerradiografías no son posiciones naturales de la cabeza genuinas. Se ha utilizado la vertical verdadera como parámetro para mediciones, todas angulares, para definir la disposición ánteroposterior del punto A´ (de construcción) para el cuerpo del labio superior, el punto Pg´para el mentón, el Labrale superior y el Labrale inferior para el bermellón de cada labio, con la finalidad de planificar correcciones ortopédicas, ortodóncicas u ortodóncicas-quirúrgicas de acuerdo a la anomalía detectada (AU)

Relación entre la Posición Natural de Cabeza y el Plano de Frankfort / Relation between the Natural Head Position and the Frankfort Plane

RESUMEN: Objetivo: El objetivo de este estudio fue comparar el paralelismo entre el Plano de Frankfort (PF) trazado en tejidos blandos y la horizontal verdadera cuando el paciente se ubica en Posición Natural de Cabeza (PNC). Materiales y métodos: La muestra contó con 97 voluntarios. A cada uno de los participantes se le tomó una fotografía facial de perfil para luego analizar mediante el software Photoshop® la angulación del PF trazado en tejidos blandos. Se utilizó t-test para determinar si existía diferencia estadística entre el PF trazado en tejidos blandos y la horizontal verdadera. Resultados: El resultado del t-test nos indica que en la muestra general existen diferencias estadísticas entre el PF trazado en tejidos blandos y la horizontal verdadera. Conclusiones: Al encontrarse los pacientes en PNC existe una diferencia estadística entre el PF trazado en tejidos blandos y la horizontal verdadera.

ABSTRACT: Aims: The aim of this study was to compare the parallelism between the Frankfort Plane (FP) traced in soft tissues and the true horizontal plane when the patient is in the Natural Head Position (NHP). Methods: The sample included 97 volunteers. A profile facial photograph of each of the participants was taken and the angulation of the FP traced in soft tissues was then analyzed with Photoshop® software. T-test was used to determine if there was statistical difference between the FP traced in soft tissues and the true horizontal. Results: The result of the t-test indicates that in the general sample there are statistical differences between the FP traced in soft tissues and the true horizontal. Conclusions: When patients are in NHP, there is a statistical difference between the FP traced in soft tissues and the true horizontal.

Relación entre oclusión dentaria y postura cráneo-cervical en niños con maloclusiones clase II y III / Relationship between dental occlusion and craniocervical posture in children with class II and III malocclusions

RESUMEN Introducción: la relación entre las maloclusiones y la postura del sistema cráneo cervical ha generado un interés creciente entre los ortodontistas. Objetivo: describir la relación entre la oclusión dentaria y la postura del sistema cráneo-cervical en niños con maloclusiones clase II y clase III. Materiales y métodos: estudio descriptivo transversal. El universo estuvo formado por 19 niños, de 7 a 12 años, con maloclusiones clase II y III de Angle. Ingresados en el Servicio de Ortodoncia de la Facultad de Estomatología de La Habana, en octubre del 2016. Se realizó examen bucal y telerradiografía. Los resultados se presentaron en tablas. Resultados: predominó la clase II de Angle, donde la distoclusión molar fue más marcada en el lado derecho (-2,95 mm) y en la clase III la mesioclusión mayor correspondió al izquierdo (2,25 mm como promedio). En ambas predominó la ½ unidad (36,8 % en clase II). El ángulo cráneo-vertebral y el espacio suboccipital estuvieron dentro del rango normal; 104,65º y 7,99 mm, en clase II y en clase III, 103,78º y 6,90 mm como promedio. La profundidad de la columna cervical fue 6,26 mm y 6,20 mm respectivamente; lo que significó una rectificación de columna cervical. Conclusiones: se encontró más frecuente la clase II de Angle. La posición de la cabeza fue normal en ambas clases y la columna cervical rectificada. Se identificaron relaciones inversas entre la magnitud de la maloclusión con la posición de la cabeza y la columna cervical.

ABSTRACT Introduction: the relationship between malocclusions and the crania-cervical system posture has generated a a growing interest among orthodontists. Objective: to describe the relationship between dental occlusion and the position of the crania-cervical system in children with class II and class III malocclusions. Materials and methods: cross-sectional, descriptive study. The universe was 19 children, aged from 7 to 12 years, class II and III Angle's malocclusions, admitted in the Orthodontics service of the Faculty of Stomatology of Havana in October 2016. Oral examination and teleradiography were performed. The results were presented in tables. Results: Class II of Angle predominated, where the molar distoclusion was more marked on the right side (-2.95 mm) and in class III the greater mesioclusion corresponded to the left (2.25 mm as average). In both, the ½ unit predominated (36.8% in Class II). The cranio-vertebral angle and the suboccipital space were within the normal range; 104.65º and 7.99 mm in class II and in class III 103.78º and 6.90 mm as average. The depth of the cervical spine was 6.26 mm and 6.20 mm respectively; which meant a rectification of the cervical spine. Conclusions: Angle's Class II was found more frequent. The position of the head was normal in both classes and also the rectified cervical spine. Inverse relationships were identified between the magnitude of the malocclusion and the position of the head and cervical spine. The objective of this work is to present a clinical case and the importance of a nurse intervention.

Clinical characteristics and surgical outcomes of congenital inferior rectus palsy with compensatory head posture of facial rotation / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To describe the clinical features of congenital isolated inferior rectus(IR)palsy with compensatory head posture of facial rotation and to analyze the effect of surgical treatment.<p>METHODS: Fifteen patients with IR muscle palsy further presenting with abnormal compensatory head posture of facial rotation were retrospectively identified from May 2014 to July 2018. Changes in the degree of facial rotation in patients were evaluated using an orthopedic goniasmometer. Variations in vertical and horizontal deviations were measured through prism and alternate cover tests, and changes in cyclotropia of pre- and postoperation were assessed by objective evaluation of eye torsion with fundus photography. IR resection was the main surgical treatment.<p>RESULTS: Among the 15 patients, 13 who were subjected to IR muscle resection or IR muscle resection combined with superior rectus muscle recession showed good results after surgery. These results included improved underaction of IR, coordination of eye movement, disappearance of abnormal facial rotation of compensatory head position, and total correction of vertical and horizontal deviation and cyclodeviation. Furthermore, each 1 mm resection of IR can correct 1.54±0.93° incyclotropia. In the other two patients with small vertical deviation who were done by inferior oblique myectomy, the improvement in facial rotation was unsatisfied, and eye motion remained uncoordinated.<p>CONCLUSION: Congenital isolated IR muscle palsy characterized by compensatory head posture of facial rotation is the main compensatory head posture. The resection of IR is effective and perfect. Mild overcorrection and undercorrection do not influence curative effect.

The effects of head rotation and tilt on oral pressure and muscle activity / 대한해부학회지

Modified Anderson Procedure in Infantile Nystagmus with Face Turn within 30 Degrees

PURPOSE: To evaluate the efficacy of modified Anderson procedure in infantile nystagmus with face turn less than 30 degrees. METHODS: This study was a retrospective review of the medical records of 13 consecutive patients who underwent a modified Anderson procedure for abnormal head position in infantile nystagmus at Pusan National University hospital from February 2002 to March 2017. We compared best-corrected visual acuity (logarithm of minimal angle of resolution, logMAR), refraction, degree of face turn, ocular motility, and angle of deviation preoperatively and at 1 week postoperatively, 6 months postoperatively, and the final visit. Recession of the yoke rectus muscles responsible for the slow phase of nystagmus was performed, depending on the direction of face turn; the medial rectus muscle of the eye to which the head was turned was recessed 10 mm, whereas the lateral rectus muscle of the contralateral eye was recessed 12 mm. RESULTS: The mean age of the patients was 8.9 (2–25) years, and the mean follow-up period after surgery was 51.3 (6–183) months. Twelve patients (92.3%) had no residual head posture or <10° at 6 months postoperatively, and three patients (23.1%) achieved this outcome with an additional operation. The mean degrees of face turn were 22.30° before surgery and 3.85° post-operatively (p = 0.001). Best-corrected visual acuity (logMAR) was 0.41 in the better eye and 0.50 in the worse eye before surgery; this improved to 0.34 and 0.45 at 6 months postoperatively (p = 0.068 and p = 0.228, respectively). Despite the large recessions involved, only one patient showed mild limitation of abduction after surgery. CONCLUSIONS: The modified Anderson procedure may be effective for correcting abnormal head position in infantile nystagmus with face turn less than 30 degrees; patients were not overcorrected.

Effect of Head Position on Maxillofacial Transverse Measurements Made on the Skull and Cone Beam Computed Tomography Scans

Article Incorrect patient positioning and the resultant image distortion occur in many radiographic examinations. This study aimed to assess the effect of tilting, rotation and tipping of the head on the accuracy of maxillofacial transverse measurements made on cone beam computed tomography (CBCT) scans. The CBCT scans were obtained in central position of 10 dry human skulls. Using three-dimensional (3D) Dolphin software, six positions namely 10° and 20° tilts, rotations and tips were reconstructed of central position. Transverse distances between landmarks were measured on 3D scans and the skulls. The intraclass correlation coefficient (ICC) and the Bland-Altman plot were used to compare the mean values measured by the two observers. For most landmarks, no significant differences were noted between the mean transverse distances measured in the six positions and those measured in central position on 3D scans (p>0.005). In conclusion, all measurements of transverse distances made on 3D scans in different positions were underestimated compared to the actual values measured on the skull.

Inclination of crown and tooth longitudinal axis in cephalometric analysis of normal occlusions / 华西口腔医学杂志

<p><b>OBJECTIVE</b>We measured and analyzed the angle between the longitudinal axis of incisor crown and tooth to provide a reference for orthodontists for selecting orthodontic methods and evaluating treatment results.</p><p><b>METHODS</b>A total of 120 participants were included according to the criteria of Andrews' six keys, and cephalometric radiograph under the instructions of modified natural head position acquirement method was performed. The angles of maxillary incisor crown longitudinal axis, tooth longitudinal axis, occlusion plane (OP), and true vertical (TV) plane were measured, as well as mandibular incisors.</p><p><b>RESULTS</b>As for maxillary incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 11.72°±4.71°, 73.29°±5.69°, and 20.04°±3.71°, respectively. For mandibular incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 16.03°±5.40°, 81.76°±4.81°, and 14.82°±4.01°, respectively. For the maxillary incisor, the angles between crown longitudinal axis and tooth longitudinal axis were mainly within 15° to 25°, whereas those for mandibular incisors were within 10° to 20°.</p><p><b>CONCLUSIONS</b>The longitudinal axis inclinations of the maxillary and mandibular incisor crown and of the incisor tooth need to be considered when cephalometric radiographs are used for treatment planning or for evaluating the treatment result.</p>

Assessment of anterior-posterior jaw relationships in Korean adults using the nasion true vertical plane in cone-beam computed tomography images / 대한치과교정학회지

OBJECTIVE: The aims of this study were to investigate a simple method for assessing anterior-posterior jaw relationships via cone-beam computed tomography (CBCT) images taken in the natural head position (NHP) relative to the nasion true vertical plane (NTVP), and measure normative data in Korean adults with normal profiles. METHODS: Subjects were selected from patients presenting for third molar extraction and evaluated as having normal profiles by three examiners. The CBCT images of 80 subjects (39 males, 41 females) were taken in the NHP according to Solow and Tallgren's method. Linear measurements of the A-point, B-point, and Pog were calculated relative to the NTVP. Student's t-test was used to assess sexual differences in these measurements. RESULTS: The mean linear measurements of the A-point, B-point, and Pog relative to the NTVP were 0.18 mm (standard deviation [SD], 4.77 mm), -4.00 mm (SD, 6.62 mm), and -2.49 mm (SD, 7.14 mm) respectively in Korean males, and 1.48 mm (SD, 4.21 mm), -4.07 mm (SD, 6.70 mm) and -2.91 mm (SD, 7.25 mm) in Korean females respectively. There were no statistically significant differences between Korean males and females (p < 0.05). CONCLUSIONS: Three-dimensional CBCT analysis using the NTVP is a simple and reliable method for assessing anterior-posterior skeletal relationships.

Efecto del aumento de la dimensión vertical oclusal en la posición natural de cabeza en pacientes portadores de prótesis removible / Effect of occlusal vertical dimension increase on natural head position in patients with removable prostheses

OBJETIVO Estudiar la variación de la posición natural de la cabeza al aumentar la dimensión vertical oclusal (DVO) en pacientes portadores de prótesis removible. PACIENTES Y MÉTODOS El estudio analítico, cuasi experimental, incluyó un total de 56 adultos mayores portadores de prótesis removibles totales y parciales (solo con grupo V remanente) atendidos en la Facultad de Odontología de la Universidad de Chile el año 2011, en los cuales se analizó la posición de la cabeza en sentido sagital al modificar la DVO aumentando progresivamente la altura oclusal en 5, 10 y 15 mm, mediante el uso de fotografías de perfil estandarizadas en posición natural de la cabeza. Hipótesis: el aumento de la DVO se asocia con una rotación posterior de la cabeza. RESULTADOS Todos los voluntarios mostraron cambio de la posición natural de cabeza, rotando posteriormente al modificar la DVO. El test ANOVA no mostró que esta diferencia fuera estadística. Hubo asociación positiva entre el cambio gradual de la DVO y el grado de rotación de la cabeza. El test de Pearson mostró asociación estadística. CONCLUSIÓN Los resultados permiten concluir que mientras mayor sea el aumento de altura oclusal mayor es la rotación posterior de la cabeza. Los hallazgos de este estudio apoyan el concepto de que existe una integración anatómica y funcional entre los distintos elementos que componen la unidad cráneo cérvico mandibular, actuando como un todo frente a la variación de uno de sus componentes.

OBJECTIVE To determine the variation in the natural head positionon increasing the Occlusal Vertical Dimension (OVD) in patients who use removable dentures. PATIENTS AND METHODS An analytical, quasi-experimental study was conducted on 56 elderly patients volunteers, carriers of removal full and partial (only with group V remaining) dentures seen in the Odontology Faculty of the University of Chile in 2011. An analysis was made of the head position in a sagittal direction to change the OVD, gradually increasing the occlusal height by 5, 10 and 15 millimeters, using standardized profile photographs of the natural head position. Hypothesis: The increase in the OVD is associated with a posterior rotation of the head. RESULTS All the volunteers showed a change in the natural head position, posteriorly rotated to change the OVD. The ANOVA test showed that this change was not statistically different. There was a positive association between a gradual change in OVD and the degree of head rotation. The Pearson test showed a statistical association. CONCLUSION It could be concluded from the results that, the greater the increase in occlusal height, the greater is the posterior rotation of the head. The findings of this study support the concept that there is an anatomical integration between the different elements that make up the cranio-cervico-mandibular unit, acting together against the variation of one of its components.

Relationships between vertical facial pattern and natural head position,cervical posture in patients with skeletal class Ⅰ relationship / 吉林大学学报(医学版)

Objective To investigate the natural head position and cervical posture in the patients with different vertical facial patterns with skeletal class Ⅰ relationship,and to clarify the relationships between vertical facial patterns and natural head position, cervical posture in the patients with skeletal class Ⅰ relationship. Methods 94 patients aged 8- 15 years old with skeletal class Ⅰ relationship were selected as the subjects.The subjects were classified into high angle group,average angle group,and low angle group according to their mandibular plane angles.The cephalometric radiographs in natural head position were taken,and the variables representing craniofacial morphology,head position,and craniocervical posture were measured.The intergroup differences in variables were compared.Results The inclinations of mandible to the true vertical and cervical column (ML/VER,ML/OPT,ML/CVT)were smallest in high angle group,and they were largest in low angle group (P 0.05). Conclusion The significant differences exist in natural head position and cervical posture among the patients with skeletal class Ⅰ relationship with different vertical facial patterns (high angle,average angle,low angle);the subjects with high angle show extended head position and cervical posture,while the subjects with low angle exhibit the opposite tendency.

Cervical vertebrae morphology in skeletal class Ⅱ and class Ⅰ malocclusion patients / 中国组织工程研究

BACKGROUND:The incidence rate of cervical abnormalities of the patients with skeletal class Ⅱ and normal occlusion has been studied abroad, but the researches on the incidence of cervical abnormalities in different malocclusion patients is rare at home. OBJECTIVE:To observe the imaging of patients with cervical abnormalities and to statistics the incidence of cervical abnormalities in different malocclusion patients through analyzing the lateral cephalogram of different malocclusion patients. METHODS:Skeletal class Ⅱ group was consisted of 93 patients, 41 male (aged 18-40 years) and 52 female (aged 22-35 years), with the A point-nasion-B point angle>5°. Class Ⅰ group was consisted of 45 patients, 31 female (aged 20-36 years) and 14 male (aged 17-38 years), with the 1°

Discrepancies in Soft Tissue Profile of Patients for Orthognathic Surgery between Preoperative Lateral Facial Photograph, Lateral Cephalogram and Supine Position on Operation Table