Photographic soft-tissue profile analysis in children at 6 years of age.

INTRODUCTION: Profile photographs can be a valuable, noninvasive tool for early orthodontic diagnosis and treatment planning. METHODS: Left-side profile photographs were obtained of 181 normal, healthy children at age 6 years. Standardized landmarks were digitized on the photographs, and several linear and angular measurements were computed. The children were divided according to dental class and sex. Comparisons were made by 2-way analyses of variance. RESULTS: Facial convexity (larger in boys than in girls), Sn-N-Sl, and nasolabial and interlabial angles differed significantly (P <.01) between the sexes. Girls had significantly less labial protrusion than boys. Facial height was significantly greater in children with dental Class II, without sex differences. All analyzed angles were significantly influenced by dental class. Facial convexity was smaller in children with dental Class II. Cutaneous class was larger, and lips were more prominent in children with dental Class II than in those with dental Class III. CONCLUSIONS: The significant relationship between dental and cutaneous classes has important implications for orthodontic diagnosis and treatment. Dental class can usefully represent facial esthetics, and orthodontic procedures that modify dental occlusion might cause important repercussions to facial soft tissues.

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.

Growth and aging of facial soft tissues: A computerized three-dimensional mesh diagram analysis.

The normal growth, development, and aging of facial soft tissues was studied by three-dimensional (3D) computerized mesh diagram analysis. The 3D coordinates of 50 soft-tissue landmarks were collected from 591 healthy white northern Italians (351 males, 240 females) 6-40 years of age. For each gender and age class, mean values were computed, and a standardized mesh of equidistant horizontal, vertical, and anterior-posterior lines was constructed. Within each age group, male meshes were superimposed on female meshes. For each gender, the 6-year-old reference mesh was superimposed on the reference mesh of each age group. The global (size plus shape) difference was evaluated by calculating the relevant displacement vectors for each landmark. Consequently, a size normalization was carried out and the shape difference was evaluated by calculating new relevant displacement vectors for each landmark. Growth and development were different along the three spatial planes: the largest increment was observed in the vertical dimension, with major modifications in the soft-tissue profile. The vertical dimension in males increased even after 30 years of age: ear dimensions increased, trichion moved superiorly and posteriorly, and pogonion, menton, and gonion moved anteriorly and inferiorly. In all age groups, size-standardized shape differences were found in the forehead, lower-third facial profile, eyes, cheeks, and ears. In each age class, male dimensions were larger than female dimensions. During childhood, gender differences in size were limited; shape differences were even less manifest. Overall, the profile was more anterior and inferior, the gonia were more inferior and more lateral, the forehead was more anterior, and the ears were larger in males than in females of corresponding age.

Elliptic Fourier analysis of facial profiles during growth and development.

The quantitative analysis of facial soft tissues is of overwhelming importance for orthodontic patients. To assess the normal age-related variations in shape, soft tissue facial profiles were studied in 96 healthy male children 3 to 11 years of age and 16 young men (age 18). Standardized left-side photographs were taken of each subject, and facial profiles were traced between trichion and cervical point. The line joining the 2 landmarks was set as the baseline, and each outline was automatically digitized and mathematically reconstructed by a 30-harmonic elliptic Fourier series expansion. The same soft tissue profile was traced and digitized from the Bolton standards of comparable age. All profiles were standardized to the same area, and shape modifications were quantified by calculating the morphologic distance between the Fourier reconstructions of each facial profile and of (1) the 18-year-old Bolton standard (MD-18) and (2) the age-related Bolton standard. Descriptive statistics were computed for each age class. On average, MD-18 was 7.23 at 3 years of age, increased between 6 and 9 years of age, and decreased hereafter, reaching 6.86 at 18 years of age. Within-group variability peaked at 8 years of age, and was minimal at 6 and 18 years of age. The current soft tissue child profiles seemed different from the profile obtained from the Bolton standards.

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.

A direct in vivo measurement of the three-dimensional orientation of the occlusal plane and of the sagittal discrepancy of the jaws.

The aim of the present investigation was to three dimensionally assess craniofacial relationships in vivo. Specifically, by using a non-invasive direct technique, the following measurements were made: 1) natural head position relative to the ground; 2) orientation of the occlusal plane relative to the subject's intrinsic facial planes; and 3) anteroposterior discrepancy of the dental bases, taking into consideration all the facial hard- and soft-tissue structures. Several dental and soft-tissue facial landmarks were directly digitized from 24 adult healthy volunteers with Angle Class I occlusions by means of an electromagnetic three-dimensional computerized digitizer. In natural head position, the three-dimensional orientation of Camper's, occlusal, and mandibular planes were measured along with the anteroposterior maxillo-mandibular discrepancies. In the frontal plane projection, all the measured planes appeared about horizontal. In the lateral plane projection, on average, Camper's plane deviated from the true horizontal by approximately 18 degrees (in a 'head flexed' direction). The occlusal plane deviated from the same horizontal by about 14 degrees, while the mandibular plane had a steeper inclination (about 30 degrees ); both planes were significantly correlated to Camper's plane. The measurements of anteroposterior jaw discrepancy revealed a wide range of sagittal relationships in the analyzed subjects. The method was found to be repeatable and fast. This direct three-dimensional in vivo assessment of the orientation of occlusal plane relative to the other facial planes could allow for a more comprehensive analysis of maxillo-mandibular sagittal discrepancies.