Development and accuracy of artificial intelligence-generated prediction of facial changes in orthodontic treatment: a scoping review / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Artificial intelligence (AI) has been utilized in soft-tissue analysis and prediction in orthodontic treatment planning, although its reliability has not been systematically assessed. This scoping review was conducted to outline the development of AI in terms of predicting soft-tissue changes after orthodontic treatment, as well as to comprehensively evaluate its prediction accuracy. Six electronic databases (PubMed, EBSCOhost, Web of Science, Embase, Cochrane Library, and Scopus) were searched up to March 14, 2023. Clinical studies investigating the performance of AI-based systems in predicting post-orthodontic soft-tissue alterations were included. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and Joanna Briggs Institute (JBI) appraisal checklist for diagnostic test accuracy studies were applied to assess risk of bias, while the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) assessment was conducted to evaluate the certainty of outcomes. After screening 2500 studies, four non-randomized clinical trials were finally included for full-text evaluation. We found a low level of evidence indicating an estimated high overall accuracy of AI-generated prediction, whereas the lower lip and chin seemed to be the least predictable regions. Furthermore, the facial morphology simulated by AI via the fusion of multimodality images was considered to be reasonably true. Since all of the included studies that were not randomized clinical trials (non-RCTs) showed a moderate to high risk of bias, more well-designed clinical trials with sufficient sample size are needed in future work.

Morfología ósea facial en cirugía ortognática. ¿existe tendencia hacia el avance facial? / Facial morphology in orthognathic surgery: is there a facial advance trend?

RESUMEN: El objetivo de esta investigación fue determinar los movimientos preferidos en maxila y mandíbula para obtener normalidad en morfología facial utilizando técnicas de superimposición en análisis 3D. Se realizó un estudio descriptivo para evaluar el desplazamiento óseo bimaxilar y del hueso hioides en sujetos clase facial tipo II y clase facial tipo III sometidos a cirugía ortognática. Para la superimposición se utilizó como puntos fijos Nasion - Silla - Porion y la sutura cigomática-maxilar. Estos puntos se superpusieron en CBCT pre quirúrgico y postquirúrgico y se evaluó el desplazamiento de la espina nasal anterior, Punto A, Punto B, mentón y del hueso hioides. Para la evaluación y comparación de las variables continuas antes y después de la cirugía ortognática se utilizó la prueba T de Student. Para la correlación entre las variables, se utilizó el Test de Spearman considerando un valor p<0,05 como diferencia significativa. 44 sujetos de entre 18 y 40 años de ambos sexos, fueron incluidos en esta investigación. En el 90 % de los sujetos se realizó un movimiento sagital de avance de la maxila. El movimiento sagital de avance mandibular se realizó en el 100 % de los sujetos con clase facial tipo II, mientras que el 100 % de los sujetos con clase facial tipo III se realizó se le retroceso mandibular. El hueso hioides presentó un avance en 26 de los 27 sujetos con clase facial tipo III. Es posible concluir que existe una tendencia al avance maxilar independiente de la deformidad facial.

ABSTRACT: The objective of this research was to determine the preferred movements in the maxilla and mandible to obtain normality in facial morphology using superimposition techniques in 3D analysis. A descriptive study was carried out to evaluate bimaxillary bone displacement and hyoid bone in subjects facial class II and facial class III undergoing orthognathic surgery. were used as fixed points for superimposition: Nasion (N) - Silla (S) - Porion (Po) and the zygomatic-maxillary suture (Z). These points were superimposed in pre-surgical and post- surgical CBCT and was evaluated to displacement of the anterior nasal spine, Point A, Point B, Chin and the hyoid bone. For the evaluation and comparison of continuous variables before and after orthognathic surgery, was used the Student's t test. For the correlation between the variables, the Spearman test is used, considering a p value <0.05 as a significant difference. 44 subjects between 18 and 40 years old of both sexes were included in this research. A 90% of subjects a was performed a maxillay sagittal movement. The sagittal movement of mandibular advancement was performed in 100% with facial class type II, while 100 % of the subjects with with facial class type III had a mandibular recession. The hyoid bone advanced in 26 of the 27 subjects with facial class type II. It is possible to conclude that there is a tendency for maxillary advancement, independent of facial deformity.

Cone beam computed tomography evaluation of the relationship between atlantodental interval and skeletal facial morphology in adolescents / Avaliação por tomografia computadorizada de feixe cônico da relação entre o intervalo atlantodental e a morfologia esquelética facial em adolescentes

Abstract Introduction: In the pediatric population, computed tomography examination of the upper cervical spine plays an important role in the diagnosis of neurological injuries involving that region. Due to the interconnected nature of the craniofacial structures, a structural change in one is expected to also cause changes in the other structures. Objective: The aim of this study was to evaluate relationships between atlantodental interval, cervical vertebral morphology, and facial structure in healthy adolescents using cone beam computed tomography. Methods: Thirty subjects aged 14-20 years (10 males, mean age: 17.2 years; 20 females, mean age: 17.9 years) were included in the study. The anterior, lateral and posterior atlantodental intervals, and vertical and anteroposterior dimensions of the first and second cervical vertebrae were evaluated from cone beam computed tomography images. Facial morphology was evaluated using 7 parameters on lateral cephalometric cone beam computed tomography images and 6 parameters on posteroanterior images. The Mann-Whitney U test and Wilcoxon test were used for statistical analyses. Results: Comparisons between males and females showed that most parameters were larger in males, with significant differences in vertical facial dimensions (anterior lower face height: p= 0.05; anterior upper face height: p= 0.001), (distance between the most internal point of the frontozygomatic suture and midsagittal reference plane; p= 0.01), (the distance between the deepest point of the right alveolar maxillar process and midsagittal reference plane; p= 0.001), and C2 vertebral dimensions. The anterior and lateral atlantodental interval values correlated with maxilla position relative to the mandible angle, and the anterior atlantodental interval correlated with lower anterior facial height (p= 0.05). Dimensional measurements of the C1 and C2 vertebrae were correlated with both anterior facial heights and some posteroanterior parameters. Conclusion: Sagittal, vertical, and transverse facial dimensions and positions were strongly associated with C1 and C2 vertebral dimensions, and the maxillomandibular relationship may affect atlantodental interval. Therefore, including craniofacial features in assessment of the atlantodental area and vertebral distances in adolescents may be beneficial.

Resumo Introdução: Na população pediátrica, a tomografia computadorizada da coluna cervical alta tem um importante papel no diagnóstico de lesões neurológicas que envolvem essa região. Devido à natureza interconectada das estruturas craniofaciais, espera-se que uma mudança estrutural em uma delas também cause alterações nas outras estruturas. Objetivo: Avaliar as relações entre o intervalo atlantodental, a morfologia vertebral cervical e a estrutura facial em adolescentes saudáveis com a tomografia computadorizada de feixe cônico. Método: Trinta indivíduos entre 14 e 20 anos (10 homens, média de 17,2 anos; 20 mulheres, média de 17,9 anos) foram incluídos no estudo. O intervalo atlantodental anterior, lateral e posterior e as dimensões vertical e anteroposterior da primeira e segunda vértebras cervicais foram avaliados a partir de imagens de tomografia computadorizada de feixe cônico. A morfologia facial foi avaliada utilizando-se sete parâmetros em imagens de tomografia computadorizada de feixe cônico cefalométricas laterais e seis parâmetros em imagens posteroanteriores. O teste U de Mann-Whitney e o teste de Wilcoxon foram utilizados para as análises estatísticas. Resultados: As comparações entre homens e mulheres mostraram que em sua maioria os parâmetros foram maiores no sexo masculino, com diferenças significantes nas dimensões faciais verticais (altura facial anterior inferior: p = 0,05; altura facial anterior superior: p = 0,001), distância entre o ponto mais interno da sutura fronto-zigomática e plano de referência médio-sagital; p = 0,01distância entre o ponto mais profundo do processo alveolar do maxilar direito e o plano de referência médio-sagital; p = 0,001) e as dimensões do corpo vertebral C2. O intervalo atlantodental anterior e lateral correlacionaram-se com o ângulo da posição da maxila em relação à mandíbula e o intervalo atlantodental anterior correlacionou-se com altura facial anterior inferior (p = 0,05). Medidas das dimensões das vértebras C1 e C2 foram correlacionadas com as alturas faciais anteriores e alguns parâmetros póstero-anteriores. Conclusão: As dimensões e posições faciais sagitais, verticais e transversais foram fortemente associadas às dimensões dos corpos vertebrais C1 e C2 e a relação maxilomandibular pode afetar o intervalo atlantodental. Portanto, incluir características craniofaciais na avaliação da área atlantodental e das distâncias vertebrais em adolescentes pode ser benéfico.

Construction and application of three-dimensional average face of Han women in northern China in facial aging morphology study / 中华整形外科杂志

Objective@#To construct the three-dimensional (3D) average face of Han women of different age groups in northern China.@*Methods@#From October 2016 to May 2017, a total of 187 facial 3D photographs of Han women aged from 20 to 65 in northern China were collected, using 3D photography technology. The subjects were divided into four groups according to their ages. The reverse engineering software and mathematical modeling software were used to construct the three-dimensional average faces of each group. Subjective description, deviation analysis and linear measurements were performed to analyze the facial morphology changing with age.@*Results@#(1) The average faces of the twenties and thirties showed insignificantly differences in periorbital area and cheilion. Those in the thirties and forties showed loosen of upper eyelids, obvious depression in frontal and temporal area, and downward and backward movement of lower face. The differences between the forties and fifties could be described as sagging and dropping, which may be caused by the drooping of facial soft tissue. They were most obvious in the lateral upper eyelid, followed by nasolabial groove and ridge, lips and chin. (2) The average epicanthus and ocular width narrowed with age, however, nasal width, height and length increased. Oral width and philtrum length significantly increased with age, accompanying with decreased upper and lower vermilion height.@*Conclusions@#The facial morphology of Han women in northern China changed most significantly when they in their forties. Facial soft tissue sagging and dropping mainly occurred in their fifties. The construction of 3D average face can be clinically applied and show the common facial features of a specific population. It has the potential to be applied in a variety of clinical studies in the future. Our findings can be used as guidance of facial rejuvenation treatment.

Three-dimensional analysis of nasolabial soft tissues while smiling using stereophotogrammetry (3dMDTM) / Análisis tridimensional de los tejidos blandos nasolabiales en sonrisa utilizando estereofotogrametría (3dMDTM)

SUMMARY: The nasolabial region is the central esthetic unit of the face and is considered one of the most important determinants of the facial esthetic. The facial morphometry of soft tissues is a very important tool in facial surgery. Advances have been made recently in the capture and analysis of 3D images, which offer great development potential in the diagnosis and treatment of facial deformities. The aim of this study was to characterize the nasolabial region of patient candidates for orthognathic surgery using 3D facial captures. A study was conducted to characterize the width of the nasal base and the nasolabial angle in adult patients through 3D photographs. 30 subjects were included, taking two 3D photos each, one in a resting position and the other smiling. The three-dimensional capture was done with the 3dMDface System. The measurements were taken with the 3dMD Vultus software. The length of the alar base was an average of 34.3 ± 2.6 mm at rest, and 39.1 ± 2.9 mm smiling. The mean of the nasolabial angle was 104.6 ± 9.6° at rest and 105.4 ± 14.3º smiling. Additionally, the distance of the alar base smiling compared to its distance at rest increased an average of 4.83 mm, whereas the nasolabial angle smiling increased an average of 0.8º compared to at rest. In this study, the nasolabial angle did not present any significant changes so that its assessments in the case of facial modifications can be standard; the width of the nasal base is significantly modified with the smile and thus a more intense study of any type of modification in this area is required.

RESUMEN: La región nasolabial es la unidad estética central de la cara y se considera uno de los determinantes más importantes de la estética facial. La morfometría facial en tejidos bandos, es una herramienta de gran importancia en Cirugía Facial. En el último tiempo, se han realizado avances en captura y análisis de imágenes 3D, las cuales ofrecen un gran potencial de desarrollo en el diagnóstico y tratamiento de las deformidades faciales. El objetivo de éste trabajo fue caracterizar mediante capturas faciales 3D la región nasolabial de pacientes candidatos a cirugía ortognática. Se realizó un estudio para caracterizar a través de fotografías tridimensionales de pacientes adultos el ancho de la base nasal y el ángulo nasolabial. Se incluyeron 30 sujetos, tomando 2 fotografías 3D a cada uno, una en posición de reposo y otra en sonrisa. Se realizó la captura tridimensional con la camara facial 3dMDface System. Las mediciones fueron realizadas con el software 3dMD Vultus. La longitud de base alar en reposo, fue en promedio de 34,3 ± 2,6 mm, y de 39,1 ± 2,9 mm, en sonrisa. Por otra parte, la media del ángulo nasolabial en reposo fue de 104,6 ± 9,6° y en sonrisa, de 105,4 ± 14,3º. Por otro lado, la distancia de la base alar en sonrisa respecto a su distancia en reposo, aumentó un promedio de 4,83 mm, mientras que el ángulo nasolabial en sonrisa, aumentó en promedio 0,8º respecto a la posición de reposo. En esta investigación, el ángulo nasolabial no presentó cambios significativos de forma que su valoración frente a modificaciones faciales puede ser estándar; el ancho de base nasal se modifica significativamente con la sonrisa de forma que su estudio debe ser más agudo frente a cualquier tipo de modificación en esta zona.

Comparación entre las técnicas de Ricketts y Mcnamara para la determinación de la posición del maxilar y la mandíbula en jóvenes del Ecuador / Comparison between Ricketts and Mcnamara techniques for the determination of the maxilla and mandible position in Ecuadorian youths

RESUMEN: Los análisis cefalométricos, a partir de una radiografía lateral de cráneo, son amplios y variados considerando tanto los patrones funcionales como los de estética facial. Entre las técnicas de medición en cefalometría, Ricketts y de McNamara son ampliamente utilizados; ambas le entregan importancia a determinar la posición del maxilar y de la mandíbula con diferentes relaciones esqueletales. El objetivo de esta investigación es comparar ambas técnicas en una población joven de Ecuador; se realizó un análisis de concordancia utilizando el índice kappa de Cohen entre los resultados de las mediciones correspondientes a 44 radiografías cefálicas laterales de sujetos jóvenes entre 18 y 27 años de edad, de ambos sexos. En relación a la posición maxilar, el 56,82 % (IC 95 %: 42,18 % - 71,45 %) coinciden en el diagnóstico de protrusión maxilar; el índice de concordancia kappa de Cohen fue de 0,599 (IC 95 %: 0,354 - 0,854) con un valor p<0,05. En relación a la posición mandibular, el 50,0 % (IC 95 %: 35,23 % - 64,77 %) coinciden en el diagnóstico de retrusión mandibular; el índice kappa de Cohen fue de 0,460 (IC 95 % 0,229 - 0,691) con un valor p<0,05. Se concluye que, a pesar de manejar puntos de referencia cefalométricos diferentes, las dos técnicas de medición cráneo-facial son útiles para el estudio de posición de maxila y mandíbula. Existen diferencias entre algunos analisis de ambos estudios que pueden incidir en la selección terapéutica de potenciales pacientes.

SUMMARY: The cephalometric analyses from a lateral cranial radiograph, are wide and varied considering both functional and facial aesthetic patterns. Among the measurement techniques in cephalometry, Ricketts and McNamara are widely used; they both give importance to determine the position of the maxilla and mandible with different skeletal relationships. The objective of this research is to compare both techniques in a young population of Ecuador. A concordance analysis was performed using Cohen's kappa index between the results of the measurements corresponding to 44 lateral cephalic radiographs of young subjects between 18 and 27 years of age, of both sexes. In relation to the maxillary position, 56.82 % (95 % CI: 42.18 % - 71.45 %) coincide in the diagnosis of maxillary protrusion. Cohen's kappa concordance index was 0.599 (95 % CI: 0.354-0.854) with a p-value < 0.05. In relation to the mandibular position, 50.0 % (95% CI: 35.23 % 64.77 %) coincide in the diagnosis of mandibular retrusion. Cohen's kappa index was 0.460 (95 % CI 0.229 - 0.691) with a p-value < 0.05. It is concluded that, despite handling different cephalometric reference points, the two craniofacial measurement techniques are useful for the study of maxilla and mandible position. There are differences between some analyses of both studies that may affect the therapeutic selection of potential patients.

Impact of skeletal divergence on oral health-related quality of life and self-reported jaw function / 대한치과교정학회지

OBJECTIVE: To investigate the differences in oral health-related quality of life (OHRQoL) and self-reported jaw function between patients with hyperdivergent and normodivergent facial types. METHODS: Eighty patients with a distinctively hyperdivergent facial type (mandibular plane angle greater than 2 standard deviations, or 42°) and 80 controls were individually matched according to age, sex, ethnicity, and treatment stage. Data were collected using self-report questionnaires such as the Oral Health Impact Profile (OHIP-14) and Jaw Functional Limitation Scale (JFLS-8). RESULTS: The mean age of the patients was 17.2 ± 4.6 years (range, 12–9 years), with most (65.0%) being female and of New Zealand European origin (91.3%). Individuals with hyperdivergent facial types had higher overall and social domain scores on the OHIP-14 (p 0.05). CONCLUSIONS: Jaw function appears to be similar in individuals with hyperdivergent and normodivergent facial morphologies. However, those with hyperdivergent facial types are more likely to self-report poorer OHRQoL than are those with normal faces, especially in relation to social aspects.

Relações entre potenciais elétricos dos músculos temporais e masseteres, força de mordida e índice morfológico da face / Relationship between electrical activity of the temporal and masseter muscles, bite force, and morphological facial index

RESUMO Objetivo Verificar e analisar possíveis correlações entre a atividade elétrica dos músculos temporais e masseteres, a força de mordida e os índices morfológicos da face, em indivíduos adultos. Método Participaram 43 indivíduos, adultos jovens de ambos os gêneros, entre 18 e 37 anos, submetidos à mensuração da face para cálculo do Índice Morfológico da Face (IMF), Eletromiografia de Superfície (EMGs) de Masseteres Direitos e Esquerdos (MD e ME), Temporais Direitos e Esquerdos (TD e TE) e obtenção da Força de Mordida (FM) nas regiões de pré-molares direitos, pré-molares esquerdos e incisivos. As provas eletromiográficas realizadas foram em repouso, Contração Voluntária Isométrica Máxima (CVIM) e mastigação habitual de uva-passa. Foi realizada análise estatística pelo coeficiente de correlação de Spearman com significância no nível de 5%. Resultados Os valores de repouso em TD e TE foram significativamente maiores que os de MD e ME. Foi encontrada correlação direta significativa entre IMF e a EMGs na prova de CVIM para o TE (rs=36, p=0,017). Observou-se correlação direta significativa entre o IMF com a EMGs durante a FM em Incisivos para os músculos TD, TE e Masseter Direito (MD). Durante as provas de força, foi possível observar correlação direta significativa entre a FM em pré-molares direitos com a EMGs do TE, MD, ME. Conclusões Não foi verificada correlação entre as respostas elétricas dos músculos temporais e masseteres, a força de mordida e os índices morfológicos da face, em indivíduos adultos a partir das provas realizadas. A atividade elétrica dos músculos temporais e masseteres parece associar-se apenas à força de mordida. Como dado de característica postural habitual, a atividade elétrica dos músculos temporais é maior que a atividade de masseteres, também independente do IMF.

ABSTRACT Purpose To analyze possible correlations between the electrical activity of masseter and temporal muscles, Bite Force (BF), and Morphological Facial Indices (MFI). Methods The study involved 43 young adults, both genders, 18 to 37 years old. The individuals were submitted to: face measurement to calculate MFI; Masseter and Temporal Surface Electromyography (sEMG) and BF measurements on right and left premolars and incisors. The following electromyographic tests were conducted: at rest position; Maximal Voluntary Isometrical Contraction (MVIC) and usual chewing of raisins. Statistical analysis was conducted using the coefficient of Spearman correlation with significance level of 5%. Results The values at rest in the temporal muscles were significantly higher than those in the masseter muscles. A meaningful correlation was found between MFI and sEMG in the MVIC test for the Left Temporal (rs=36, p=0.017). A significant correlation was observed between FMI and sEMG during BF in incisors for temporal muscles and the Right Masseter. During the force tests, it was possible to observe a meaningful correlation between BF in right premolars and the sEMG of the Left Temporal and Masseters. Conclusion No correlation was found between the sEMG of temporal and masseter muscles, BF, and FMI in adult individuals based on the tests performed. The SEMG of temporal and masseter muscles seems to be associated only with BF. As a datum of habitual postural characteristic, the electrical activity of temporal muscles is higher than the activity of masseters, also regardless of MFI.

Nasal deformity in subjects with class III facial deformities / Deformidad nasal en sujetos con deformidad facial clase III

Dentofacial deformities present some shades and variations that determine the inclusion of different anatomical components as part of the disease; the aim of this study was to ascertain the nasal characteristics in patients with a Class III dentofacial deformity. A descriptive study was conducted on 20 patients diagnosed with a Class III facial deformity and a surgical indication; frontal and lateral as well as CT images were taken to analyze variables of nasal morphology and deformities associated with the nasal bridge, tip and septum. The results showed that the nasal angles are outside normal parameters and that the basal width of the nose is approximately 3 mm smaller than the intercanthal width; 45% of the subjects have lateral deviations, 50% bridge deformity and 80% septum deviation. It is concluded that there are nasal deformities in subjects with a Class III facial deformity and that this component must be carefully evaluated in the preoperative stage.

Las deformidades dentofaciales presentan algunos matices y variaciones que determinan la inclusión de diferentes componentes anatómicos dentro de la enfermedad; el objetivo de esta investigación es conocer las características de la nariz en pacientes con deformidad dentofacial de clase III. Se desarrollo un estudio descriptivo en 20 pacientes con diagnóstico de deformidad facial declase III e indicación quirúrgica; se estudiaron análisis fotográficos frontales y laterales así como tomografías computadorizadas para analizar variables de morfología nasal y deformidades asociadas al puente nasal, punta nasal y septo nasal. Los resultados demostraron que los ángulos nasales se encuentran fuera de los parámetros de normalidad y que el ancho basal de la nariz es aproximadamente 3 mm menor que el ancho intercantal; el 45% de los sujetos presentó desviación lateral, 50% deformidad del puente nasal y el 80% desvío de septo nasal. Se concluye que existen deformidades nasales en sujetos con deformidad facial de clase III y que este componente debe ser evaluado criteriosamente en la etapa preoperatoria.

Facial soft tissue in subjects with class II and class III facial deformities: preliminary results / Tejido blando facial en sujetos con deformidad facial clase II y clase III: resultados preliminares

Class II and class III skeletal anomalies require treatments that are both esthetic and functional, so the purpose of this investigation was to study the relationship between facial soft and hard tissues of patients with class II and class III deformities in the lower third of the face. A descriptive study was designed which included class II subjects with a SNB angle less than 78 and class III with a SNA angle less than 80. The soft tissue width was analyzed in relation to the Pg point, A point, B point, and upper and lower incisor cervical points. The naso-labial angle and interincisal angle were also analyzed. The studies were done using cone beam computerized tomography and analyzed with the software Simplant O&O (Materialise, Belgium). The results revealed similarities in the measurements of the facial width soft tissues with differences of less 1 mm in the Pg point, A point, B point, upper incisor point; the greatest differences were observed between the two groups in thelower incisor cervical point, with almost 5 mm difference in tissue size. The naso-labial angle also presented differences between the two groups, being more closed in the class III than in the class II subjects (approximate difference of 6). It can be concluded that there are minimal differences in the soft tissue width in class II and class III subjects; other parameters can be analyzed to search for differences that influence treatment planning and strategies for these patients.

Las anomalías esqueletales de clase II y clase III requieren tratamientos que asocian estética y función. El objetivo de esta investigación fue estudiar la relación entre tejidos blandos y duros faciales de pacientes con clase II y clase III facial, a nivel del tercio inferior facial. Se diseño un estudio descriptivo donde se incluyeron sujetos clase II con un ángulo SNB menor de 78 y clase III con un ángulo SNA menor de 80. Se analizó el ancho de tejidos blandos en relación a los putos Pg, punto A, punto B, y puntos cervicales de dientes incisivos maxilar y mandibular; también se analizaron los ángulos nasolabial e interincisivo; los estudios se realizaron en tomografía computadorizada cone beam y analizados en el software Simplant O&O (Materialise, Belgium). Los resultados demostraron semejanzas en las mediciones obtenidas en el ancho facial de tejidos blandos con diferencias menores a 1 mm en los puntos Pg, punto A, punto B y cervical incisivo maxilar; en relación al punto cervical del incisivo mandibular se observaron las mayores diferencias entre ambos grupos, cercanas a 5 mm de diferencia de tamaño en los tejidos; el ángulo nasolabial también presento diferencias entre ambos grupos, siendo en los sujetos clase III mas cerrado que en sujetos clase II (diferencia aproximada de 6). Se puede concluir que existen mínimas diferencias en el ancho de tejidos blandos en sujetos de clase II y clase III; otros parámetros pueden ser analizados para búsqueda de diferencias que influyan en planificaciones y estrategias terapéuticas para estos sujetos.

Relaciones de forma y proporción del incisivo central maxilar con medidas faciales, línea mediana dentaria y facial en adultos / Relationships between shape and proportion of the maxillary central incisor with facial measurements, dental and facial midline in adults

El propósito de este estudio fue relacionar la forma y proporción del incisivo central maxilar (ICM) derecho con la forma facial y ubicación de las líneas medianas dentarias y facial. Se realizó un estudio de corte transversal sobre una muestra por conveniencia constituida por 118 pacientes de ambos sexos, con una edad promedio de 25,09±7,71 años, escogidos según criterios de inclusión. En cada caso, fueron medidos el largo y ancho del ICM derecho, proporción dentaria resultante entre estas medidas, líneas medianas dentarias en relación a la línea mediana facial. Estas medidas se correlacionaron con las medidas faciales para forma y clase facial. Los resultados revelaron que la forma dentaria más frecuente encontrada fue la ovoide; las medidas promedio de largo y ancho para el ICM fueron de 10,28±0,91 mm y 8,69±0,57 mm, respectivamente. En mujeres fue 9,98 mm y 8,55 mm, y en hombres de 10,62 mm y 8,86 mm. La proporción dentaria fue de un 85%. Se encontraron coincidencias de las líneas medianas dentarias maxilar, mandibular y facial sólo en un 18% de los casos, y los tipos de contornos gingivales más frecuentes fueron de tipo estético (97%). No hubo relación entre medidas dentarias y faciales para las distintas clases faciales (análisis de varianza, y pruebas de comparaciones múltiples de Scheffe), sin embargo, encontramos que en todas las clases faciales de ambos sexos, predominó el tipo mesofacial y la clase I facial (57%). No se puede establecer una correlación entre forma dentaria y forma facial de manera significativa, por lo que otros parámetros también deben ser tomados en cuenta.

The purpose of this study was to relate the shape and proportion of the right maxillary central incisor with facial shape and location of dental and facial median lines. Cross-sectional study on a convenience sample consisting of 118 patients of both sexes was performed, with an average age of 25.09±7.71 years, selected according to inclusion criteria. In each case, were measured the length and width of right maxillary central incisor, tooth ratio resulting of these measures and medium tooth lines in relation to the midline. These measures were correlated with measures of facial shape and facial class. The results revealed that the most common tooth shape found was ovoid; average length and width for the maxillary central incisor were 10.28±0.91 mm and 8.69±0.57 mm, respectively; of 9.98 mm and 8.55 mm in women, and 10.62 mm and 8.86 mm in men. The dental proportion was 85%. Matches between the median lines of maxillary teeth, jaw and face were only found in 18% of cases, and the most common types of gingival contours were aesthetic (97%). There was no relationship between dental and facial for different facial types (analysis of variance and multiple comparison tests of Scheffe) measures, however, we found that all facial classes in both sexes, prevailed mesofacial and class I facial types (57%). Unable to establish a correlation between tooth shape and facial shape significantly, so other parameters should also be taken into account.

Association between maximum bite force and craniofacial morphology in an Amazonian population with normal dental occlusion / Associação entre força máxima de mordida e morfologia craniofacial em população Amazonense com oclusão normal

The aim of this study was to determine the maximum bite force (MBF) in Amazonian children and young adolescents with normal dental occlusion, the average craniofacial morphology, and investigate associations between craniofacial morphology and body mass with MBF. Ninety-seven children and young adolescents, 21 with primary dentition and 76 with permanent dentition and normal dental occlusion were included in the study. Subjects were from Amazonian tribes studying at three schools in Leticia, Amazonas, Colombia. MBF was determined by means of a digital hydraulic pressure gauge. Body mass index (BMI), facial morphology index, and dental arches transverse dimensions were computed in each subject. Mann Whitney test, a one-tailed non-parametric statistical analysis, was used to contrast MBF between primary dentition and permanent dentition. The same statistical analysis was used to determine MBF statistical differences between the various facial morphologies. Pearson correlation statistical analysis was used to evaluate associations between MBF with BMI, dental arches transverse dimensions or facial morphology. Statistical significance was determined at 95 percent level of confidence. A significant difference was found for the MBF between subjects in primary dentition (incisors: 116.57 ± 48.30; right molars: 368.38 ± 105.52; left molars: 322.76 ± 83.77) and those in permanent dentition (incisors: 260.88 ± 85.73; right molars: 459.63 ± 167.11; left molars: 645.67 ± 170.60). In addition, an association was observed between MBF and facial morphology index. It was concluded that MBF significantly increases from primary to permanent dentition in subjects with normal dental occlusion. Furthermore, this study agrees with other reports stating that MBF is associated with the morphology of the face, but not with BMI or dental arches transverse dimensions.

O presente estudo teve como objetivo determinar a força máxima de mordida (FMM) e morfologia craniofacial média de crianças e adolescentes da região do Amazonas com oclusão dentária normal, e investigar associações entre índice de massa corpórea (IMC), morfologia craniofacial e FMM. Participaram do estudo 97 crianças e adolescentes, 21 deles com dentição primária e 76 com dentição permanente, todos com oclusão dentária normal. Os indivíduos pertencentes a tribos amazônicas estudavam em três escolas em Leticia, Amazonas e Colombia. A FMM foi determinada utilizando medidor de pressão hidráulica digital. Índice de massa corporal (IMC), índice morfológico, e dimensões transversais dos arcos dentários de cada indivíduo foram registrados. O teste de Mann Whitney, análise unicaudal não paramétrica, foi aplicado na comparação da força máxima de mordida em dentição decídua e permanente. A mesma análise estatística foi utilizada para determinar as diferenças estatísticas acerca da FMM entre as diferentes características da morfologia facial. O coeficiente de correlação de Pearson foi empregado para avaliar as associações entre FMM e IMC, dimensão transversal dos arcos dentários ou morfologia facial. A significância estatística foi determinada com intervalos de 95% de confiança. Diferença significativa foi observada para FMM entre sujeitos com dentição decídua (incisivos: 116.57 ± 48.30; molares direitos: 368.38 ± 105.52; molares esquerdos: 322.76 ± 83.77) e aqueles com dentição permanente (incisivos: 260.88 ± 85.73; molares direitos: 459.63 ± 167.11molares esquerdos: 645.67 ± 170.60).

Three dimensional analysis of the upper airway and facial morphology in children with Class II malocclusion using cone-beam computed tomography / 대한치과교정학회지

OBJECTIVE: The aim of this study was to evaluate the volumes and areas of the upper airways in children with Class II malocclusion, using three dimensional cone-beam computed tomography (CBCT) and to compare the volumetric and cross-sectional measurements and cephalometric variables to investigate possible relationships between the upper airway and facial morphology. METHODS: CBCT scans were obtained from 37 subjects (17 boys and 20 girls; average age, 11.02 years). The upper airway volumes and areas were measured, and compared with cephalometric variables. RESULTS: The area of the PNS-posterior plane (SPP) was significantly smaller in the Class II malocclusion group (p 0.05). The Class II malocclusion group showed significantly smaller values of PFH, mandibular body length, pog to N perp and showed larger values of FMA, ANB, and facial convexity than the Class I malocclusion group. The volume of the upper airway in front of PNS point (WN) showed negative correlation with ANB (p < 0.05). CONCLUSIONS: The Class II malocclusion group had a narrower upper airway associated with a decreased posterior facial height and a divergent growth pattern than the Class I malocclusion group.

Facial three dimensional surface imaging: an overview

The surface facial imagings have many applications in medical fields. The recent past has seen great advances in three dimensional imaging which include laser scanning or stereophotogrammetry. Here, we reviewed various systems with reference to image acquisition, advantages and disadvantages. Examples of important clinical application with reference to the human face are also discussed. Finally, a 3D imaging system at Universiti Sains Malaysia (USM) is described.

Cephalometric study on head posture according to the classification of malocclusion / 대한치과교정학회지

It has been known that head posture may influence directly and/or indirectly the growth and development of craniofacial morphology and can also be influenced by the funtional demand of physiologic activity. It was reported that facial morphology has close relationships with hyoid bone position and head posture. In many previous studies, Natural Head Posture(NHP) was guided, and also it was shown that NHP has high degree of reproducibility. Otherwise, There was few study about the relationship of head posture, with routine cephalometric film which is used for clinical orthodontic purpose. In this study, according to the Wits and ANB of initial cephalometric film which was taken with vertical pendulum as representative of true vertical reference line. We classified the subjects which is comprised of 60 adult female patients into Class 1, II, III (Cl I, II, III)and we tried to find out the correlation of head posture and hyoid bone position according to the classification of malocclusion. As a result of our research, we found the followigs. 1. In comparison of vertical position of hyoid bone relative to the cranial base. the position of hyoid bone of Cl III was lower than that of Cl II. 2. In comparison of anteriorpostes or position of hyoid bone, relative to the cervical column. The position of hyoid bone of Cl III was more anterior than that of a II 3. in comparison of vertical position of hyoid bone relative to mandible. There was no significant correlation aumoug the groups of malocclusion. 4. ANB and Wits showed no significant correlation with hyoid bone position. 5. The relative extension of head, which was noted in Cl II, showed negative with Sum, ANB. 6. In Cl II and Cl III, Post to Ant facial height showed positive correlation with NSL/VER.

A study on the maximum bite force and facial morphology according to chewing side preference / 대한치과교정학회지

This study was undertaken to investigate the distribution of the chewing side preference and variations in the maximum bite force and facial morphology according to chewing side preference since unilateral chewing may cause morphologic and functional anomalies. 50 dental students who had no signs or symptoms of masticatory system and Angle's Class I relationship in posterior segments were selected, and divided into two groups, that is, 25 in bilateral chewing group(19 male and 6 female) and 25 in unilateral chewing group(10 male and 15 female). Maximum bite force was estimated and posteroanterior cephalogram were measured and statistically analyzed. The results were as follows: 1. There were more students with bilateral chewing side preference(68%) and unilateral chewing side group consisted of right side preference(68%) and left side preference(32%). 2. There was no significant difference in the strength of max. bite force between the right and left side in bilateral chewing group. The bite force of the chewing side was greater in the unilateral chewing group but less in the non-chewing side compared to those of bilateral chewing group with no significant difference. Max. bite force of chewing side was greater than that of non-chewing side in the unilateral chewing group(Female : p<0.05). Max. bite force of males was about twice in that of females in both groups(p<0.05). Max. bite force of chewing side of the unilateral chewing group was similar to that of the bilateral chewing group, but that of non-chewing side was less than that of the bilateral chewing group. 3. In comparison of the facial morphology, there was no statistically significant difference in the size between the right and left side of the bilateral chewing group and between chewing and non-chewing side of the unilateral chewing group.