Soft-tissue 3D Facial Imaging in Children and Adolescents: Towards the Definition of New Reference Standards

In the last decades, head and face imaging has shifted from two-dimensional (2D) representations (conventional radiography, photography) to three-dimensional (3D) techniques that can better depict the complex morphology of this part of the body, since they can provide a large number of additional anthropometric information [1-3]. 3D imaging systems can be divided into volumetric (computed tomography, cone beam computed tomography, magnetic resonance imaging) and optical surface instruments (laser scanning, moiré techniques, stereophotogrammetry, patterned light techniques) [4]. These last are safe and not invasive, and provide a 3D representation of the external (cutaneous) facial surface.

Normalizing surface electromyographic measures of the masticatory muscles: Comparison of two different methods for clinical purpose.

PURPOSE: To compare a new normalization technique (wax pad, WAX) with the currently utilized cotton roll (COT) method in surface electromyography (sEMG) of the masticatory muscles. METHODS: sEMG of the masseter and anterior temporalis muscles of 23 subjects was recorded while performing two repetitions of 5s maximum voluntary clenches (MVC) on COT and WAX. For each task, the mean value of sEMG amplitude and its coefficient of variation were calculated, and the differences between the two repetitions computed. The standard error of measurement (SEM) was calculated. For each subject and muscle, the COT-to-WAX maximum activity increment was computed. Participant preference between tasks was also recorded. RESULTS: WAX MVC tasks had larger maximum EMG amplitude than COT MVC tasks (P<0.001), with COT-to-WAX maximum amplitude increments of 61% (temporalis) and 94% (masseter) (P=0.006). WAX MVC had better test-retest repeatability than COT. For both MVC modalities, the mean amplitude (P>0.391) and its coefficient of variation were unchanged (P>0.180). The WAX task was the more comfortable for 18/23 subjects (P=0.007). CONCLUSION: WAX normalization ensures the same stability level of maximum EMG amplitude as COT normalization, but it is more repeatable, elicits larger maximum muscular contraction, and is felt to be more comfortable by subjects.

Cinemática de variáveis de técnica-chave nos flic flacs de ginastas de elite / Kinematics of key technique variables in the backward handsprings of elite gymnasts

INTRODUÇÃO: A ginástica é o esporte de habilidades fechadas mais antigo e espetacular. Contudo, parâmetros técnicos de execução geralmente são somente ensinados por treinadores experientes. Desta maneira, existe uma lacuna de informações objetivas sobre o desempenho de ginastas (referências cinemáticas). OBJETIVO: No presente estudo, tentamos quantificar movimentos de inversão linear e de hiperextensão durante a execução de flic flacs. MÉTODOS: Foi efetuada uma detecção não invasiva de flic flacs com o auxílio de um instrumento óptico eletrônico 3D. Treze marcadores esféricos retrorreflexivos (1 cm de diâmetro) foram posicionados no corpo de 9 ginastas experientes: maléolos laterais direito e esquerdo, cabeça da fíbula, trocanter maior, acrômio, olecrano, processo estiloide da ulna e vértex. Na mesma sessão e após um período de aquecimento, cada participante executou 15 repetições de flic flacs. Dez repetições forma analisadas, e os trajetos 3D das 13 manobras medidos. RESULTADOS: Em média, os homens obtiveram altura vertical maior (mulheres, 62% da altura; homens, 58%). O alinhamento dos membros inferiores foi homogêneo entre os ginastas: ângulos posteriores de joelho variaram entre 80° e 118°. Nenhuma abdução de membro inferior foi observada: a largura de joelho foi 7 cm menor do que a largura intertrocanter; a largura de tornozelo foi 8 cm menor do que a largura de joelho. Na saída do movimento, o ângulo tronco-coxa apresentou excelente alinhamento corporal, com valores bem próximos de 180°. As mulheres executaram a fase de apoio das mãos com pulsos mais próximos do que os homens (homens, 134% de largura de ombro; mulheres, 121%). CONCLUSÃO: Os resultados podem fornecer informações para melhor conhecimento, definindo assim, a execução de padrão-ouro obtida de ginastas de elite com poucas lesões.

INTRODUCTION: Gymnastics is the most ancient and spectacular closed skills sport. Nonetheless, technical parameters of performance are often taught only by experienced trainers. Thus, there is a lack of objective data about gymnastics performance (kinematics references). OBJECTIVE: In the current study, we tried to quantify linear and hyperextension back movements during performance of backward handsprings. METHODS: A noninvasive detection of backward handsprings was made using a 3D optoelectronic instrument. Thirteen spherical retro-reflective markers (1-cm diameter) were positioned on the body of 9 experienced gymnasts: right and left lateral malleolus, fibular head, greater trochanter, acromion, olecranon, styloid process of the ulna; vertex. In the same session and after a warm-up period, each participant performed 15 repetitions of backward handsprings. Ten repetitions were analyzed, and the 3D tracks of the 13 landmarks measured. RESULTS: On average, men performed longer backward handsprings than women (men, 122% of height; women, 98%); women attained larger vertical height (women, 62% of height; men, 58%). Lower limb arrangement was homogenous among the gymnasts: posterior knee angles ranged between 80° and 118°. No lower limb abduction was observed: knee width was 7 cm smaller than intertrochanter width; ankle width was 8 cm smaller than knee width. At take-off, the trunk-thigh angle presented excellent body alignment, with values very close to 180°. Women performed the handstand phase with closer wrists than men (men, 134% of shoulder width; women, 121%). CONCLUSION: The results may offer data to improve understanding, defining gold-standard execution taken from high level gymnasts with few injuries.

Morphometry of the orbital region soft tissues in Down syndrome.

The orbital region of subjects with Down syndrome (DS) has been scanty described so far. We wanted to detail the morphologic characteristics of the soft tissue orbital region in Italian and North Sudanese subjects with DS. The three-dimensional coordinates of 10 landmarks on the orbital soft tissues were obtained using computerized anthropometry in 53 Italian and 64 North Sudanese subjects with DS aged 4 to 52 years, and in 461 (Italian) and 682 (North Sudanese) sex- and age-matched controls. From the landmarks, linear distances, ratios, areas, and angles were calculated, z scores computed, and compared by t-tests and analyses of covariance. In North Sudanese DS subjects, intercanthal width and height-to-length ratio were increased; biorbital width, eye height, length, and area were reduced. Eye fissure and orbital inclinations relative to Frankfort plane were reduced, whereas orbital inclinations versus the true horizontal were increased. In Italian DS men, orbital height and height-to-length ratio were increased, eye length was decreased; orbital inclination versus the true horizontal was increased. For almost all measurements, a significant effect of age was found. No effects of sex were found. Ethnic group influenced orbital height, area, and orbital inclination versus Frankfort plane. All paired measurements had similar discrepancies on both sides. The orbital soft tissues of North Sudanese DS subjects differed from those of their reference subjects, but this was only partially true for Italian subjects. The 2 ethnic groups had different alterations in their soft tissue orbital regions that were influenced by age, but not by sex.

Craniofacial growth in ectodermal dysplasia. An 8 year longitudinal evaluation of Italian subjects.

OBJECTIVE: To identify the main directions of growth of facial structures in subjects with hypohidrotic ectodermal dysplasia (HED). MATERIALS AND METHODS: The 3D noninvasive facial measurements were collected in 12 subjects (6 boys, 6 girls) with HED during four assessments (at 8, 11, 12, and 15 years) using an electromagnetic digitizer. The modifications of linear distances in the upper, middle, and lower third of the face were analyzed and compared with cross-sectional data obtained in normal healthy coetaneous. For each distance, differential values between the last and the initial data were calculated individually, separately for a first (8-11 years) and a second growth period (12-15 years). RESULTS: In the first time span, the growth of all facial measurements was reduced in HED subjects compared with control subjects. During this interval, most of the HED children underwent a functional and/or prosthetic treatment. During adolescence, the width and height of the lower and upper facial thirds showed a larger growth in HED subjects than in control subjects, while all facial depths and all distances in the middle facial third maintained a reduced growth. CONCLUSIONS: The deviation from normal facial growth of HED subjects tends to lessen with age. Functional and prosthetic appliances may have enhanced facial growth.

Soft-tissue facial characteristics of attractive Italian women as compared to normal women.

OBJECTIVE: To compare the facial characteristics of two different groups of attractive women with those of reference women. MATERIALS AND METHODS: The three-dimensional coordinates of 50 facial landmarks were collected in 71 healthy reference women (18-30 years old) and in 24 coetaneous "attractive" women selected during two different beauty competitions; soft tissue facial angles, distances, areas, and volumes were computed and compared using analysis of variance. RESULTS: When compared with reference women, both groups of attractive women shared several similar facial characteristics: relatively large forehead (P < .001), reduced mandible (P = .008), and rounded face (reduced surface-to-volume ratio, P = .002). They had a more acute soft tissue profile, an increased upper facial width (P < .001) and middle facial depth, larger mouth, and more voluminous lips (P = .005) than reference women. CONCLUSIONS: Both groups of attractive women had several facial characteristics suggesting babyness. Nonetheless, each group of women was characterized by a different development of these features. Esthetic reference values can be a useful tool for clinicians, but should always consider the characteristics of individual faces.

Soft-tissue facial characteristics of attractive and normal adolescent boys and girls.

OBJECTIVES: To identify possible esthetic canons in facial size and shape of Italian adolescent boys and girls. MATERIALS AND METHODS: The three-dimensional coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw, ears) were collected in 231 healthy, reference adolescents (10- 17 years old) and in 93 similar age group "attractive" adolescents selected by a commercial casting organization. Soft-tissue facial angles, distances, areas, and volumes were computed. Comparisons were made with analysis of variance. RESULTS: Attractive adolescents had wider, shorter, and less deep faces than reference adolescents, with a relatively larger forehead and maxilla, and a reduced mandible relative to the maxilla. Lips were larger and more prominent, and the nasolabial angle was reduced, but in older boys the effect was reversed. The prominence of the soft-tissue profile, and of the maxilla relative to the mandible, were larger in attractive boys, but smaller in attractive girls than in their reference peers. In the horizontal plane, attractive "young" adolescents had a flatter face, while the opposite pattern was observed in the "old" adolescents, with a relatively more prominent chin. Attractive adolescents had smaller noses than reference subjects of the same age and sex. CONCLUSIONS: Overall, all the measurements appeared sufficiently homogenous, and the quantitative characteristics of an "attractive" face well defined. Esthetic reference values can be used to determine optimal timing and goals in orthodontic treatment.

Three-dimensional facial morphometry of attractive children and normal children in the deciduous and early mixed dentition.

OBJECTIVES: To identify possible esthetic canons in facial size and shape of Italian children. MATERIALS AND METHODS: The three-dimensional coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw, ears) were collected in 220 healthy reference children (4-9 years old) and in 89 "attractive" children of a similar age group selected by a commercial casting organization. Soft-tissue facial angles, distances, and volumes were computed. Comparisons were made with the Student's t-test. RESULTS: Attractive children had a larger face than the reference children, with a larger maxilla and forehead; overall, their faces were wider and deeper, but less vertically developed. Lips were more voluminous in attractive children, with a higher mouth. The nose was larger in attractive children than in reference children. The soft-tissue facial profile was more convex in attractive children, with a more prominent maxilla relative to the mandible. CONCLUSIONS: Overall, considering that in the analyzed ages body growth and dental changes are very fast and individually determined, all the measurements appeared sufficiently homogenous, and the quantitative characteristics of an "attractive" face well defined. Esthetic reference values can be used to determine optimal timing and goals in orthodontic treatment.

Three-dimensional facial morphometry of attractive adolescent boys and girls.

OBJECTIVES: To identify reference standards and possible esthetic features of facial size and form of Italian adolescent boys and girls. METHODS AND SUBJECTS: A three-dimensional electromagnetic digitizer was used to collect the coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw, ears) in 231 healthy, reference adolescents (10-17 years old) and in 93 "attractive" adolescents selected by a commercial casting; soft tissue facial angles, distances and volumes were computed. RESULTS: Attractive adolescents had wider and shorter faces than reference subjects of the same age and sex, with relatively larger upper and middle facial thirds, and a reduced mandible relative to the maxilla. Lips were larger and more prominent, and the nasolabial angle was reduced, but in older boys the effect was reversed. The prominence of the soft-tissue profile, and of the maxilla relative to the mandible, were larger in attractive boys, but smaller in attractive girls than in their reference peers. Attractive adolescents had a relatively less prominent chin relative to the lower lip, with increased values of the mentolabial angle. In the horizontal plane, attractive "young" adolescents had a more obtuse mandibular convexity angle, while the opposite pattern was observed in the "old" adolescent subjects, with a relatively more prominent chin. Attractive adolescents had smaller noses than reference subjects of the same age and sex. CONCLUSION: Esthetic reference values have been identified which could be used to determine optimal timing and goals in orthodontic treatment.

Three-dimensional facial morphometry of attractive Italian women.

OBJECTIVES: To identify reference standards and possible esthetic features in facial proportion and form of Italian adult women. METHODS AND SUBJECTS: A three-dimensional electromagnetic digitizer was used to collect the coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw, ears) in 71 healthy, reference women (18-30 years old) and in 48 "attractive" women selected during a beauty competition; soft tissue facial angles, distances and volumes were computed. RESULTS: Attractive women had wider faces with a relatively larger upper facial third (forehead); a larger facial width relative to facial height. The mouth was larger, and lips were more prominent; the interlabial angle was reduced. Overall, the soft-tissue profile was more prominent, with a larger maxillary prominence relative to the mandible. Faces in the attractive women were more flat in the horizontal plane. For several of the analyzed measurements, similar patterns were observed for the 36 women participants to the semi-final stage of the beauty competition, the 12 finalists, and the winner. The winner of the beauty competition deviated from the reference women more than the other two groups of attractive women. CONCLUSION: Esthetic reference values were determined for a population of 18-30 year olds that reflect contemporary society.

Three-dimensional palatal development between 3 and 6 years.

OBJECTIVE: To measure palatal landmarks of healthy nonpatient children aged 3 to 6 years with a normal deciduous dentition and to evaluate palatal shape independent of size. MATERIALS AND METHODS: Fifty-eight dental casts of children with a normal and complete deciduous dentition were obtained and digitized with a computerized 3D instrument. At all ages, male and female data did not differ (Student's t-test), so the pooled values were considered. Dimensions were compared between ages by analyses of variance. RESULTS: Palatal slope and height increased significantly as a function of age (P < .001). Palatal length did not change with age (average: 23.1 mm). In the frontal plane, the intermolar width increased slightly with age by about 1.8 mm at the second molars, 1.1 mm at the first molars, and 0.9 mm at the canines. Palatal height in the frontal plane did not change in the posterior part of the palate, but decreased anteriorly. The intercanine distance increased by 0.9 mm with age. However, this change did not reach statistical significance. CONCLUSIONS: Between 3 and 6 years of age, palatal shape changed and became proportionally higher in both the frontal and sagittal planes.

Abnormal variations in the facial soft tissues of adult uremic patients on chronic dialysis.

Renal osteodystrophy is a common complication of uremic patients, mainly when they are in long-term regular dialysis treatment. The craniofacial skeleton is one of the peculiar targets of renal osteodystrophy, the more dramatic pattern of which is a form of leontiasis. To assess facial deformities in uremic conditions and to understand the possible relation with hyperparathyroidism, the three-dimensional coordinates of 50 soft tissue facial landmarks were obtained by an electromagnetic digitizer in 10 male and 10 female patients (aged 53-81 years) with chronic renal insufficiency and regular dialysis treatment. Similar three-dimensional coordinates were also collected for 34 healthy individuals of the same age, ethnicity, and sex. From the landmarks, facial distances, angles, and volumes were calculated according to a geometrical model of the face. Data were compared with those collected in the normal subjects by computing z-scores. Facial volumes of the chronic renal insufficiency patients were significantly larger than those of the control subjects. The increment was particularly evident in the facial middle third (maxilla), leading to a significant inversion of the mandibular-to-maxillary ratio. The lips tended to be more prominent (reduced interlabial angle). Some of these facial modifications (facial and nose height, maxillary dimensions, mandibular shape) were significantly related to the clinical characteristics of the patients (duration of renal insufficiency, duration of dialysis, parathormone (PTH) plasma levels). In regular dialysis treatment, some of the facial modifications are related to hyperparathyroidism, which supports the need for a strict metabolic control also in the early phase of uremia.

Cephalometric and in vivo measurements of maxillomandibular anteroposterior discrepancies: a preliminary regression study.

One of the aims of the present investigation was to assess three-dimensionally the anteroposterior discrepancy of dental bases using a noninvasive direct procedure. A second aim was to verify the relationship of three-dimensional soft-tissue measurement to the well-established two-dimensional cephalometric assessments of anteroposterior discrepancy. Dental and facial landmarks were directly digitized on 20 orthodontic and maxillofacial surgery patients aged 8 to 26 years using an electromagnetic three-dimensional computerized digitizer. The anteroposterior maxillomandibular discrepancy was measured by calculating the linear distances between the projections of subnasal and sublabial landmarks on the occlusal plane, subnasal and sublabial landmarks on Camper's plane, and insertion of maxillary and mandibular median labial frenula on the occlusal plane. From lateral cephalograms of the same patients, the following measurements were obtained: subspinale point-nasion-supramentale point (ANB) angle; corrected ANB angle that compensates for the position of the maxilla and rotation of the mandible relative to the cranial base; Wits appraisal; MM-Wits, linear distance between the projections of points A and B on the bisector of the palatal plane to mandibular plane angle; and soft-tissue Wits, linear distance between the projections of soft-tissue points A and B on the bisecting occlusal plane. The best two-dimensional vs three-dimensional linear regression (r = 0.91) was found between Wits appraisal and the linear distances between the projections of maxillary and mandibular median labial frenula on the occlusal plane (Wits = -1.05 x 3D measurement - 3.75). The three-dimensional evaluation of the sagittal discrepancy of the jaws directly performed in vivo may allow a more complete analysis of a patient's soft-tissue drape together with the underlying hard-tissue structure.