Mentoplastia de reducción en armonización facial: reporte de caso / Reduction genioplasty in facial harmonization: case report

Introducción: la mentoplastia es una herramienta importante en la cirugía estética del tercio inferior de la cara, permite la armonización mediante movimientos del segmento osteotomizado en diferentes planos. Objetivo: describir el análisis prequirúrgico para una mentoplastia en un paciente con anomalía esquelética y macrogenia en las dimensiones vertical y horizontal. Resultados: el análisis concluye una reducción de mentón en dos planos, un procedimiento infrecuente en el manejo quirúrgico del tercio inferior. Discusión: aunque la mayoría de las correcciones realizadas en la actualidad implican un avance o descenso del mentón en casos de retro o microgenia, es importante reconocer otras deformidades y evaluar las proporciones faciales, la oclusión dental, las mediciones cefalométricas y las imágenes fotográficas identificando las necesidades específicas de cada paciente. Conclusión: realizar una correcta identificación de la clase esquelética y un análisis estético facial permite identificar el tipo de deformidad y planificar su manejo quirúrgico.

Introduction: Sliding Genioplasty is an important tool in the aesthetic surgery of the lower third of the face, it allows the harmonization by moving the osteotomi-zed segment in different planes. Objective: to describe the pre-surgical analysis for a Genioplasty in a patient with skeletal anomaly and macrogenia in the vertical and horizontal dimensions. Results: the analysis concludes a chin reduction in two planes, an infrequent procedure in the surgical management of the lower third. Discussion: although most of the corrections made today involve an advance or descent of the chin in cases of retro or microgenia, it is important to recognize other deformities and evaluate facial proportions, dental occlusion, cephalometric measurements and photographic images identifying the specific needs of each pa-tient. Conclusion: performing a correct identification of the skeletal class and an aesthetic facial analysis allows identifying the type of deformity and planning its surgical management.

Percepción de las asimetrías del mentón entre ortodoncistas, odontólogos especialistas, estudiantes y pacientes / Perception of chin asymmetries among ecuadorian orthodontists, specialist dentists, students and patients

Introducción: Estudios previos han demostrado diferencias en la percepción de asimetrías dentales y faciales entre profesionales de la odontología y personas no expertas. Sin embargo, la literatura sobre las diferencias en la percepción de las asimetrías del mentón es limitada. Objetivo: Comparar la percepción estética de las asimetrías del mentón entre ortodoncistas, odontólogos especialistas, estudiantes y pacientes de la Facultad de Odontología de la Universidad Central del Ecuador. Métodos: Estudio observacional, analítico y transversal. El universo estuvo conformado por 36 ortodoncistas, 77 odontólogos especialistas, 96 estudiantes y 2580 pacientes de esta Facultad. El tamaño de la muestra fue de 30 participantes para cada grupo. Se modificó digitalmente la posición transversal del mentón de 0° a 6° en las fotografías de dos sujetos (hombre-mujer) ecuatorianos. La evaluación se realizó por medio de una escala visual análoga. Resultados: Las fotografías de asimetrías del mentón con 0° de desviación fueron calificadas como muy estéticas y las asimetrías con 6° fueron poco estéticas para los cuatro grupos. Los ortodoncistas, odontólogos especialistas y estudiantes consideraron como límite estético los 2° de desviación del mentón para la fotografía del sujeto femenino y masculino. Los límites estéticos fueron los 2° de desviación para el sujeto femenino y 3° para el sujeto masculino. Se encontraron diferencias significativas entre los grupos de evaluadores y las fotografías (p < 0,05). Conclusiones: Los ortodoncistas percibieron la estética facial cercana a la norma de la asimetría del mentón, que tiene un papel importante en la percepción de la estética facial(AU)

Introduction: Previous studies have shown differences in the perception of dental and facial asymmetries between dental professionals and non-experts. However, the literature on differences in the perception of chin asymmetries is limited. Objective: Compare the aesthetic perception of chin asymmetries among orthodontists, specialist dentists, students and patients of the Faculty of Dentistry of the Central University of Ecuador. Methods: Observational, analytical and cross-sectional study. The universe was made up of 36 orthodontists, 77 specialist dentists, 96 students and 2580 patients from this Faculty. The sample size was 30 participants for each group. The transverse position of the chin was digitally modified from 0° to 6° in the photographs of two Ecuadorian subjects (male-female). The evaluation was carried out by means of an analogous visual scale. Results: The photographs of asymmetries of the chin with 0° of deviation were qualified as very aesthetic and the asymmetries with 6° were unsightly for the four groups. Orthodontists, specialist dentists and students considered as an aesthetic limit the 2nd deviation of the chin for the photography of the female and male subject. The aesthetic limits were 2° of deviation for the female subject and 3° for the male subject. Significant differences were found between the groups of evaluators and the photographs (p < 0.05). Conclusions: Orthodontists perceived facial aesthetics close to the norm of chin asymmetry, which has an important role in the perception of facial aesthetics(AU)

Morfología cefalométrica de la sínfisis del mentón en individuos jóvenes de la ciudad de Quito-Ecuador / Cephalometric morphology of chin symphysis in young individuals from the city of Quito-Ecuador

Resumen Introducción: La sínfisis del mentón aporta equilibrio, simetría y armonía al rostro. Por ser una estructura anatómica mandibular muy importante y altamente modificable en cirugía estética, se considera indispensable conocer su morfología y así obtener una correcta interacción en el diagnóstico, pronóstico y terapéutica médico-odontológica. Objetivo: Determinar la morfología sínfisis del mentón en jóvenes adultos de la ciudad de Quito- Ecuador, año 2019, mediante la identificación de las longitudes sagitales y coronales. Metodología: Este estudio tuvo un enfoque cuantitativo, tipo descriptivo-observacional, con temporalidad retrospectiva. Se calibraron, analizaron y trazaron 384 radiografías digitales laterales de adultos jóvenes de la ciudad de Quito-Ecuador, año 2019 en el software AutoCAD-2019. Resultados: Existió una elevada frecuencia de la forma geométrica cuadrada (60%) con respecto a la rectangular (40%), adicionalmente se identificó que la figura cuadrada es más frecuente en individuos de sexo femenino y sujetos clase I (56%) y II (70%), además de todos los patrones de crecimiento vertical hipodivergentes (58%), normodivergentes (64%) e hiperdivergentes (57%). Conclusiones: La forma cuadrada de la sínfisis del mentón es mayor que la forma rectangular. Por la originalidad de los resultados, se sugiere realizar nuevos estudios que correlacionen la morfología mentoniana con las diferentes estructuras cráneo-maxilofaciales.

Abstract Introduction: The chin symphysis contributes to the balance, symmetry and harmony of the face. Since it is an important anatomical jaw structure and highly modifiable in aesthetic surgery, it is considered crucial to know its morphology and, thus, obtain a correct interaction in the diagnosis, prognosis and medical-dental therapy. Objective: To determine the symphysis morphology of the chin in young adults in the city of Quito, Ecuador, in the year 2019, through the identification of sagittal and coronal lengths. Methodology: This study had a quantitative approach, descriptive-observational type, with retrospective temporality. We calibrated, analyzed and plotted 384 lateral digital radiographs of young adults from the city of Quito-Ecuador, year 2019 in the software AutoCAD-2019. Results: There was a high frequency of the square geometric shape (60%) in comparison to the rectangular one (40%). Additionally, it was identified that the square figure is more frequent in female individuals and class I (56%) and II (70%) subjects, in addition to all the hypodivergent (58%), normodivergent (64%) and hyperdivergent (57%) vertical growth patterns. Conclusions: The square shape of the chin symphysis is larger than the rectangular shape. Due to the originality of the results, it is suggested to carry out new studies that correlate chin morphology with the different cranio-maxillofacial structures.

About chin (genioplasty) surgery / Sobre cirugía del mentón (genioplastía)

Facial harmony is the consequence of a proper balance between all facial structures. The identification and classification of morphologic characteristics that detract from facial harmony is most effectively accomplished by clinical examination. The maintenance of the ratios between the facial thirds, correct spatial bone position and soft tissues accommodation are all factors that directly contribute in a balanced facial profile. The chin, likewise, contributes significantly in facial balance, mainly in the profile view. Expressive changes on chin position are associated with the perception of strong or delicate characters. Thus, over the years, a series of studies has been constructed focusing on mandibular osteotomies techniques that enable changes in chin position: advances, setback, extrusion, intrusion, widening, narrowing and asymmetry. This study aims to address historical and technical aspects of genioplasty; associating patient's condition with the surgical techniques that can be applied for correction of chin deformities.

La armonía facial es la consecuencia del balance entre las estructuras facial. La identificación y clasificación de las características morfológicas que están acompañando la armonía facial son mas efectivas al realizar un estudio de análisis facial. La obtención de promedios entre los tercios, corrección especial de la posición del hueso y la acomodación de los tejidos blandos son factores directamente involucrados en el balance del perfil. El mentón, contribuye significativamente en este balance. Cambios expresivos en la posición del mentón son asociados con la percepción de características fuertes o delicadas. Durante los años, una serie de estudios han sido desarrollados enfocándose en las osteotomías mandibulares y técnicas capaces de alcanzar los cambios en la posición del mentón: avances, retrocesos, extrusiones, ensanchamientos, estrechamientos y asimetrías. Este estudio pretende orientar las condiciones históricas y técnicas respecto de la genioplastia; la asociación de las características del paciente con la técnica quirúrgica pueden ser aplicadas para la corrección de las deformidades.

Temblor Mentoniano: Reporte De Un Caso Aislado / Chin Tremor: Report Of An Isolated Case

Resumen El temblor mentoniano o genioespasmo es un desorden del movimiento de carácter involuntario, rítmico, hereditario autosómico dominante, exacerbado por situaciones de estrés o emocionales. Registrado por primera vez en 1894, en Italia. Se reporta una niña de 4 años de edad con temblor mentoniano desde el año de edad, sin precedente de herencia, con respuesta exitosa al uso de Toxina Botulínica.

Abstract The chin tremor or geniospasm is an involuntary, rhythmic, autosomal dominant hereditary movement disorder, triggered by stress or emotional situations. Registered for the first time in 1894, in Italy. We report a 4-year-old girl with mental tremor from one year of age, with no previous inheritance, with a successful response to the use of Botulinum Toxin.

Ángulo de convexidad facial y proyección del mentón en pacientes en postoperatorio de rinoseptoplastia / Angle facial convexity and projection of the chin in patients undergone of rhinoplasty

Introducción: La relación de la nariz con la morfología facial no es solo estructural. Numerosos estudios sugieren la relación entre la función respiratoria nasal y el de-sarrollo craneofacial. Objetivo: Determinar la mejoría en el ángulo de convexidad facial y proyección del mentón en pacientes en postoperatorio de rinoseptoplastia. Diseño: Estudio observacional analítico tipo corte transversal. Metodología: Mues-tra de 43 pacientes, 26 de género femenino y 17 masculino, entre 12 y 43 años, sometidos a rinoseptoplastia con evolución postoperatoria mínima de 3 meses. Se analizaron las variables de edad, sexo, ángulo de convexidad facial de Legan y proyección del mentón según González Ulloa antes y después de la cirugía, así como tiempo postquirúrgico. Resultados: El ángulo de convexidad facial se redujo 3,72°+2,19. En la técnica de González Ulloa, se evidenció avance del pogonion 2,53 mm+ 1,60. De los 43 pacientes, un 72%, mostró cambios favorables en el án-gulo de convexidad facial y en la proyección del mentón. Los mejores resultados se evidenciaron en menores de 16 años y evolución postquirúrgica mayor a 1 año. Discusión: A diferencia de otras investigaciones, observamos cambios significativos en pacientes adultos. Tal hecho nos lleva a otras interrogantes sobre mecanismos adicionales que pudieran influir en los patrones de crecimiento facial. Conclusiones: La rinoseptoplastia al considerarse un procedimiento que mejora la función respira-toria nasal, favorece cambios neuromusculares y endocrinos que permiten un mejor desarrollo del perfil facial en especial del tercio inferior.

Introduction: The relation between the nose and the facial morphology is not only structural. Numerous studies have demonstrated also a relationship between nasal respiratory function and craniofacial development. Objective: To determine the im-provement in the angle of facial convexity and chin projection in patients in the postoperative period of rhinoseptoplasty. Design: Cross-sectional study. Methods: 43 patients were selected. 26 women and 17 men between 12 and 43 years old, undergoing Rhinoplasty with minimum 3 months of postoperative evolution. We analyzed the variables of age, sex, Legan's angle of facial convexity and projection of the chin according to Gonzalez Ulloa before and after surgery, as well as post-surgical time. Results: The angle of facial convexity was reduced X + D.S 3.72 ° + 2.19. The technique of González Ulloa showed progress of the pogonion X + D.S 2.53 mm + 1.60. Of the 43 patients, 72%, showed positive changes at the angle of facial convexity and the projection of the Chin. Best results were apparent in children under 16 years and more than 1 year postsurgical evolution. Discussion: Unlike other research, we observe significant changes in adult patients. This fact leads to other questions about additional mechanisms that might influence the facial growth patterns. Conclusions: Rhinoseptoplasty is a procedure that improves the nasal respiratory function, favors neuromuscular and endocrine changes that allow better development of the facial profile especially in the lower third.

Comparison of the three-dimensional structures of mandibular condyles between adults with and without facial asymmetry: A retrospective study / 대한치과교정학회지

OBJECTIVE: This retrospective study compared the three-dimensional (3D) structure of mandibular condyles between adults with and without facial asymmetry, and whether it influences menton deviation. METHODS: Sixty adult patients were classified into symmetry and asymmetry groups based on the menton deviation on postero-anterior radiographs. The right/left differences of 3D measurements were compared between the two groups, and measurements were compared separately on the right and left sides. The correlations between menton deviation and the right/left differences were analyzed. RESULTS: The mediolateral dimension, neck length, condylar angles to the anteroposterior reference (PO) and midsagittal reference planes, and neck and head volumes showed significantly larger right/left differences in the asymmetry group compared to the symmetry group. Separate comparisons of the right and left sides between the two groups showed that the neck was significantly shorter and neck and head volumes were significantly smaller on the left side, which was deviated side in the asymmetry group. Pearson's correlation analysis showed significant positive correlations of menton deviation with right/left differences in neck length, condylar angle to the PO plane, and neck and head volumes in the asymmetry group. CONCLUSIONS: In individuals with facial asymmetry, menton deviation is associated with the right/left differences caused by a smaller condyle on the deviated side, particularly in neck length and neck and head volumes.

Cortical and cancellous bone in mandibular symphysis: implications in osteosynthesis and osteotomy / Hueso cortical y esponjoso en sínfisis mandibular: implicancias en osteotomía y osteosíntesis

The aim of this study was to quantify the presence of cortical and cancellous bone in the mandibular symphysis. A descriptive study was conducted using cone beam computed tomography where skeletal class I and class III subjects were included, defined according to characteristics detected on dental, clinical and dental occlusion x-rays. From the 3D reconstruction, sections were used in relation to the axial axis of the teeth of the anterior sector; the amount of buccal cortical, cortical, lingual, inferior cortical and cancellous bone as well as symphysis height were determined. The measurements were taken using routine methods and analyzed with ANOVA and Tukey's HSD test with p <0.05 for statistical significance. 20 skeletal class I subjects aged 23 years (± 4.5) and 20 class III subjects aged 22 years (± 5.2) were included. Symphysis height was significantly greater in skeletal class III subjects, exceeding by 0.8 mm the height of class I subjects; the buccal cortical bone presented on average 2 mm less at different dental levels, whereas the lingual cortical and inferior basal bones were significantly larger than the buccal cortical bone. The cancellous and cortical bones did not present any significant differences between the two groups (p=0.093). The buccal and basilar cortical bone is smaller than lingual cortical bone.

El objetivo fue determinar la presencia de hueso cortical y esponjoso en sínfisis mandibular. Se realizó un estudio descriptivo en tomografías computadorizadas cone beam donde se analizaron sujetos clase I y clase III esqueletal definidos según características dentales, clínicas y radiográficas de oclusión dental y características radiográficas. Desde la reconstrucción 3D se utilizaron cortes en relación al eje axial de los dientes del sector anterior; en ellos se determinó la cantidad de hueso cortical bucal, cortical, lingual, cortical inferior, hueso esponjoso y altura de sínfisis. Las mediciones fueron realizadas con métodos de rutina y fueron analizados con la prueba ANOVA y HDS Turkey considerando un valor de p <0.05 para considerar significancia estadística. 20 sujetos clase I esqueletal con 23 años (+ 4.5) y 20 sujetos clase III esqueletal con edad de 23 años (+ 4.5) fueron incluidos. La altura de sínfisis fue significativamente mayor en sujetos de clase III esqueletal, superando por 0.8 mm la altura de sujetos clase I; el hueso cortical bucal presento en promedio menor de 2 mm en diferentes niveles dentarios, mientras que la cortical lingual y basal inferior fueron significativamente mayor que la cortical bucal. El hueso esponjoso y hueso cortical no presentó diferencias significativas entre ambos grupos (p=0.093). La cortical bucal y basilar son menores que el hueso cortical lingual.

Plastia del músculo mentalis una alternativa de mentoplastia en casos seleccionados / Mentalis muscle plasty an alternative genioplasty in selected cases

Introducción: la plastia del músculo mentalis (PMM) es una técnica quirúrgica para realizar mentoplastia de aumento que no requiere uso de implantes, logrando incrementar la proyección horizontal y/o vertical del mentón en pacientes seleccionados, usualmente se realiza concomitante con la rinoplastia para compensar el perfil; aunque también se puede hacer de manera aislada. Objetivos: determinar si el uso de la PMM es eficaz para incrementar la proyección del mentón, además evaluar si la proyección del mentón obtenida por esta técnica se sostiene con el paso del tiempo. Materiales y métodos: estudio observacional prospectivo, en donde se realizó PMM a 27 pacientes (20 mujeres y 7 hombres) entre los 18 a 49 años, posterior a la realización del procedimiento quirúrgico se realizó seguimiento en consulta a cada paciente por un periodo de dos años (24 meses). Resultados: en los 27 pacientes llevados a PMM, se determinó una longitud de la microgenia preoperatoria a corregir de 4,9±1,4 cm; se logró aumentar quirúrgicamente la proyección del mentón en un promedio de 4 ±0,7 cm sin uso de implantes; quedando una longitud residual de aproximadamente 1,5 ±0,9 cm, durante el seguimiento a 24 meses cada paciente aumento aproximadamente 1,5 ±0,8 cm sin cambios significativos hasta el momento del seguimiento. Conclusiones: PMM es procedimiento eficaz para la realización de mentoplastia de aumento en pacientes con microgenias leves seleccionados a partir del test de tracción positiva del mentón, los cambios producidos se sostienen hasta los dos años posterior a su realización.

Introduction: mentalis muscle plasty (MMP) is a surgical technique for genioplasty without the use of fillers, thereby increasing the horizontal or vertical chin projection in selected patients, usually performed concomitantly with rhinoplasty to compensate the profile; although it can also make isolation. Objectives: To determine whether the use of the mentalis muscle plasty is effective in increasing chin projection in selected cases also determine whether chin projection obtained by this technique is sustained over time. Materials and Methods: A prospective observational study, where plasty of the mentalis muscle was performed in 27 patients (20 women and 7 men) between 18 to 49 years, after the completion of the surgical procedure monitoring in consultation with each patient was performed by a period of two years (24 months). Results: In the 27 patients who underwent plasty of the mentalis muscle length microgenia correct preoperative was determined in 4.9 ± 1.4 mm; was achieved surgically increase the projection of the chin in an average of 4 ± 0.7 mm without the use of implants; leaving a residual length of about 1.5 ± 0.9 mm, while monitoring each patient 24 months increased about 0.4 ± 0.5 mm without significant changes until the time of follow-up. Conclusions: plasty of the mentalis muscle is an effective to perform genioplasty in patients with mild microgenias selected from test positive traction chin procedure, performing this surgical technique does not require the use of implants and changes they hold up to two years from its completion

The genial tubercle: A prospective novel landmark for the diagnosis of mandibular asymmetry / 대한치과교정학회지

INTRODUCTION: Identifying menton (Me) on posteroanterior cephalograms and three-dimensional (3D) cone-beam computed tomography (CBCT) images is difficult, because the midpoint of the symphyseal area is not identifiable after the mandibular symphysis fuses at an early age. The aim of this study was to evaluate the reliability of the identification of the genial tubercle (GT) in patients with mandibular asymmetry and to compare it with that of the traditional landmark, Me. METHODS: The samples comprised 20 CBCT images of adults with mandibular asymmetry. Two examiners performed the identifications and measurements. Me and GT were marked, and the anteroposterior, vertical, and transverse distances to the three reference planes were measured on 3D-reconstructed CBCT images. The intra- and inter-examiner reliability of landmark identification of Me and GT were assessed using the intraclass correlation coefficient (ICC) and Bland-Altman plots. RESULTS: The Me and GT landmarks showed excellent reliability (ICC ≥ 0.993) three-dimensionally. In the transverse evaluation, the ICC values of the GT (range, 0.997–0.999) tended to be slightly higher than those of Me (range, 0.993–0.996). In the Bland-Altman plots for the two separate assessments, Me showed a maximum error of 1.76 mm in the transverse direction, whereas the GT showed a maximum error of 0.96 mm in the 95% limit. CONCLUSIONS: Our results suggest that both Me and GT are clinically reliable and equally useful landmarks for the evaluation of mandibular asymmetry on CBCT images.

Morfología cefalométrica de la sínfisis del mentón en individuos jóvenes de la ciudad de Quito-Ecuador

Introducción: La sínfisis del mentón aporta equilibrio, simetría y armonía al rostro. Por ser una estructura anatómica mandibular muy importante y altamente modificable en cirugía estética, se considera indispensable conocer su morfología y así obtener una correcta interacción en el diagnóstico, pronóstico y terapéutica médico-odontológica. Objetivo: Determinar la morfología sínfisis del mentón en jóvenes adultos de la ciudad de Quito- Ecuador, año 2019, mediante la identificación de las longitudes sagitales y coronales. Metodología: Este estudio tuvo un enfoque cuantitativo, tipo descriptivo-observacional, con temporalidad retrospectiva. Se calibraron, analizaron y trazaron 384 radiografías digitales laterales de adultos jóvenes de la ciudad de Quito-Ecuador, año 2019 en el software AutoCAD-2019. Resultados: Existió una elevada frecuencia de la forma geométrica cuadrada (60%) con respecto a la rectangular (40%), adicionalmente se identificó que la figura cuadrada es más frecuente en individuos de sexo femenino y sujetos clase I (56%) y II (70%), además de todos los patrones de crecimiento vertical hipodivergentes (58%), normodivergentes (64%) e hiperdivergentes (57%). Conclusiones: La forma cuadrada de la sínfisis del mentón es mayor que la forma rectangular. Por la originalidad de los resultados, se sugiere realizar nuevos estudios que correlacionen la morfología mentoniana con las diferentes estructuras cráneo-maxilofaciales.

Introduction: The chin symphysis contributes to the balance, symmetry and harmony of the face. Since it is an important anatomical jaw structure and highly modifiable in aesthetic surgery, it is considered crucial to know its morphology and, thus, obtain a correct interaction in the diagnosis, prognosis and medical-dental therapy. Objective: To determine the symphysis morphology of the chin in young adults in the city of Quito, Ecuador, in the year 2019, through the identification of sagittal and coronal lengths. Methodology: This study had a quantitative approach, descriptive-observational type, with retrospective temporality. We calibrated, analyzed and plotted 384 lateral digital radiographs of young adults from the city of Quito-Ecuador, year 2019 in the software AutoCAD-2019. Results: There was a high frequency of the square geometric shape (60%) in comparison to the rectangular one (40%). Additionally, it was identified that the square figure is more frequent in female individuals and class I (56%) and II (70%) subjects, in addition to all the hypodivergent (58%), normodivergent (64%) and hyperdivergent (57%) vertical growth patterns. Conclusions: The square shape of the chin symphysis is larger than the rectangular shape. Due to the originality of the results, it is suggested to carry out new studies that correlate chin morphology with the different cranio-maxillofacial structures.

The influence of age on lip-line cant in adults: a cross-sectional study / 대한치과교정학회지

OBJECTIVE: The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity. METHODS: In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18-48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle). RESULTS: The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had 1.6° of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001). CONCLUSIONS: While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults.

The relationship between condyle position, morphology and chin deviation in skeletal Class III patients with facial asymmetry using cone-beam CT / 대한치과교정학회지

OBJECTIVE: Facial asymmetry is usually evaluated from the difference in length and angulation of the maxilla and mandible. However, asymmetric position or shape of the condyle can also affect the expression of asymmetry. The purpose of this study was to evaluate the correlation between condylar asymmetry and chin point deviation in facial asymmetry. METHODS: Cone-beam CT images of fifty adult skeletal Class III patients were studied. Thirty patients who had more than 4 mm menton deviation were categorized in the asymmetric group. Twenty patients with less than 4 mm menton deviation were assigned to the symmetric group. Anteroposterior and transverse condyle positions were evaluated from the cranial base. The greatest mediolateral diameter (GMD) of the condyle in the axial plane and angulation to the coronal plane were measured. The height and volume of the condyles were evaluated. RESULTS: The symmetric group had no statistical difference between both condyles in position, angulation, GMD, height and volume. In the asymmetric group, the non-deviated side condyle was larger in GMD, height and volume than the deviated side. There was no statistical difference in condyle position and angulation. The GMD, height difference and condylar volume ratio (non-deviated/deviated) were positively correlated with chin deviation. From the linear regression analysis, condylar volume ratio was a significant factor affecting chin deviation. CONCLUSIONS: These findings suggests that the non-deviated side condyle is larger than the deviated side. In addition, condylar asymmetry can affect the expression of facial asymmetry.

Correlation between menton deviation and dental compensation in facial asymmetry using cone-beam CT / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry. METHODS: Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis. RESULTS: From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (Delta Angle LM6-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (Delta Angle UM6-FH plane (dev.-ndev.)) (p<0.01). Two angular measurements (Delta Angle LM6-Mn plane (dev.-ndev.), Delta Angle UM6-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant r2 value of 0.589. CONCLUSIONS: This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.

Posteroanterior cephalometric study of frontal ramal inclination in chin-deviated individuals / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to compare the right and left differences of frontal ramal inclination in chin-deviated individuals. METHODS: Thirty adult patients with clinically apparent chin deviation were selected as the chin-deviated group, and 30 adult patients with symmetric faces were selected as the control group. On the posteroanterior cephalograms, the frontal ramal inclination was measured, and the right and left differences were compared and analyzed. RESULTS: While the control group did not show right and left differences of frontal ramal inclinations, the chin-deviated individuals showed right and left differences of frontal ramal inclination. In chin-deviated individuals, the frontal ramal inclinations of the non-deviated side were statistically greater than those of the deviated side. The right and left differences of frontal ramal inclinations, with menton deviation and the right and left differences of maxillary heights showed statistically significant correlation. CONCLUSION: We conclude that the frontal ramal inclinations should be considered in the diagnosis of facial asymmetry.