Biomedical subjects

C Sforza

Publications and source records attributed to C Sforza.

At least 55 records · Page 3Linked to original sources

PubMed1999

Simplified cephalometric lines for the estimation of muscular lines of action.

In the study of masticatory muscle performance, one of the biomechanical variables that can be estimated is the mechanical advantage of the masticatory muscles, namely, the ratio between the muscular moment arm and the bite force moment arm. In the present study, the position of the estimated line of action of the masseter muscle, drawn between gonion and orbitale (Go-Or) relative to dental (occlusal plane) and skeletal (Frankfort plane) references was analyzed in 431 pretreatment lateral cephalograms of orthodontic patients (195 males, 236 females) aged 6 to 50 years, and in the lateral tracings of the Bolton standards (6 to 18 years of age). The following measurements were evaluated: (1) skeletocutaneous class (soft tissue equivalent of Wits appraisal, linear distance in millimeters between the projections of points A' and B' on the occlusal plane); (2) angle between the Go-Or line and the perpendicular to the occlusal plane at the molar occlusal point; and (3) angle between the Go-Or line and the Frankfort plane. In the patients, the skeletocutaneous class ranged between--14.5 and 15.5 mm, without any sex- or age-related differences. The angle between the Go-Or line and the perpendicular to the occlusal plane was, on average, 39 degrees (range 15 to 53 degrees), and it decreased with advancing age; while the average angle between Go-Or and Frankfort plane was 42 degrees (range 30 to 54 degrees), and it increased in older patients. No effects of sex were found. The two angles were significantly correlated to each other, while no correlations were found with the sagittal jaw discrepancy. Similar results were obtained on the Bolton tracings. Overall, the present cephalometric analogue could be useful in biomechanical simulations.

Adolescent↗

PubMed1999

Dental arch size in healthy human permanent dentitions: ethnic differences as assessed by discriminant analysis.

Race and ethnicity variably influence the form of the human craniofacial complex. In the present study, the effects of ethnicity and sex on the global size of normal adult dental arches were analyzed. The dental arches of 47 northern Chilean mestizos (25 men, 22 women) and 95 northern Italian Caucasians (50 men, 45 women) were cast in stone. All subjects had a complete dentition in both arches. In all models the coordinates of dental cusp tips were digitized using an image analyzer. The center of gravity of each tooth was computed and arches were interpolated using a polynomial model (y = ax + bx2 + cx3 + dx4). In all arches, the intercanine, intermolar, and mid-intercanine to mid-intermolar distances were computed from the dental centers of gravity. These arch distances were entered in a linear discriminant function analysis. The polynomial model accurately interpolated data points in all instances, and most of the dental arch form was determined by the first and second degree coefficients. On average, Italian Caucasian arches were smaller than Chilean mestizo arches. Male mean distances were larger than female distances regardless of ethnic group or arch. The linear discriminant analysis performed between male and female arches within ethnic groups was significant only for both Italian Caucasian arches, but the percentage errors for the classification of a new individual were very high (about 30%). Conversely, Italian Caucasian arches could always be discriminated from Chilean mestizo arches of the same sex with a much smaller error.

Adult↗

PubMed1998

Facial volume changes during normal human growth and development.

BACKGROUND: To describe normal soft tissue growth and development of the human face through volume changes and to assess the presence of sexual dimorphism. METHODS: Facial landmark identifications (2,023) were performed on 1,347 healthy Caucasian children and adolescents, ages 6-18 yr, and young adults, ages 19-32 yr. Three-dimensional coordinates of 22 facial landmarks were collected by automated infrared photogrammetry. Facial volumes and selected linear distances and ratios were calculated and averaged for age and sex. RESULTS: Whereas in females in the 14-15 age group, the face had almost completed its growth relative to the adult group, in males a large increase was still to occur, in general agreement with previous reports on craniofacial growth, which suggested a strong tendency in males for growth to continue for several years beyond that seen in females. The male vs. female comparison reflected the different growth patterns. On average, within each age group volumes were significantly larger in males than in females, with some exceptions in the 11-12 age group, where female growth velocity showed a spurt. Sexual dimorphism in facial volume did not appear in different parts of the face to the same extent: a large part of male facial volume preponderance occurred in the lower third of the face. CONCLUSIONS: From 6 yr of age to adulthood, facial soft tissues increased their volumes by >40%, with different growth patterns in boys and girls.

Adolescent↗

PubMed1998

Foot asymmetry in healthy adults: elliptic fourier analysis of standardized footprints.

The size and shape of paired structures differ in the left and right sides of the body. Shape characteristics should be analyzed separately from size to supply information about the normal variations of human organs. In the present study, the within-subject normal symmetry of footprint shape and size was analyzed from a mathematical standpoint. On the standardized left and right footprints of 46 healthy adults (23 women and 23 men; 19-26 years old), the outline of each foot excluding the toes was identified and its shape was quantified independently from size by the elliptic Fourier analysis. The symmetry in shape was quantified on an intra-subject basis by calculating a morphologic distance D between the mathematical reconstructions of the left and right footprints of each subject. Symmetry in size was assessed by the right-to-left area ratio and found to be very good for all subjects; it ranged from 0.948 to 1.049. The subjects were also grouped by sex, and mean values were calculated. Within-subject symmetry in the footprint shape appeared high, with morphologic distances ranging between 8.94 and 2.66 in men and between 7.15 and 3.09 in women. No consistent associations between footprint symmetry and age, body height and weight, or shoe size were found. On average, women had more symmetric size-standardized footprints than did men (women: mean 4.57, SD 1.14; men: mean 5.46, SD 1.7; p < 0.05). Mean size-independent shapes of male and female left and right footprints were also calculated. Together with the analysis of individual asymmetry, they could be used for the quantitative diagnosis of borderline patients.

Adult↗

PubMed1998

A three-dimensional computerized mesh diagram analysis and its application in soft tissue facial morphometry.

A modified computerized mesh diagram analysis that allows rapid and independent quantifications of soft tissue facial size and shape in the three-dimensional space is presented. Normal references are provided, and the application of the method is also exemplified by the analysis of two maxillofacial surgical patients. The Three-Dimensional Facial Morphometry method has been used for the collection of the x, y, z coordinates of 22 soft tissue landmarks in 50 men and 50 women (all healthy young white adults). The method detects the three-dimensional coordinates of retroreflective, wireless markers positioned on selected facial landmarks with two charge-coupled device cameras, working in the infrared field. The midpoint between the right and left tragus landmarks served as the origin of the coordinate axes, and the landmark coordinates were rotated, setting the intercantheal line horizontal on both the frontal and the horizontal planes, and the Camper's plane inclined at -7.5 degrees on the sagittal plane. A standardized mesh of equidistant horizontal (dimension: half the upper face width), vertical (half the vertical projection of upper face height), and anteroposterior (half the horizontal projection of upper face depth) lines was consequently constructed. The lattice was replicated on the entire face and comprised 84 parallelepipeds. Both male and female reference meshes had a harmonious and symmetric appearance, with gender differences in facial size but not in facial shape. The standard normal reference was superimposed on the patient's tracing, and the global (size plus shape) difference was then evaluated by the calculation of the relevant displacement vectors for each soft tissue landmark. A global difference factor was calculated as the sum of the modules of all the displacement vectors. Consequently, a size normalization was performed, and the shape difference (size-standardized) was then evaluated by the calculation of new relevant displacement vectors for each landmark, as well as a shape--global difference vectors.

Adult↗

PubMed1998

Quantitative analysis of penile ultrasonographic shape during the erectile cycle: a new diagnostic tool for erectile dysfunction? Repeatability of the method and preliminary results.

Penile modifications during erection interest not only penile length and circumference, but also its size and shape. In this investigation, the size and shape repeatability of a single standardized ultrasonographic image of penis during flaccidity and erection was quantified in a group of 19 patients complaining of erectile dysfunction. The penis of each patient was placed in the dorsal position and scanned by a 10 MHz linear ultrasonographic probe at the site of maximal corporeal size: (1) during flaccidity; (2) after an intracorporeal injection of 10 micrograms alprostadil; and (3) after a genital stimulation. Each scan was repeated three times for each patient and printed. On each print the outline of the tunica albuginea was drawn, digitized, and mathematically reconstructed by Fourier series that allow a separate quantification of the size and shape differences. Reliability of the tunica albuginea outline and repeatability of probe positioning were separately assessed within patient and functional phase, and found to be good. The actual examinations of two impotence patients performed using the described method are also given. The shape of the corpora cavernosa may be potentially indicative of the homogeneous function of the tunica albuginea, and it may be of use in patients' follow up.

Adult↗

PubMed1998

Preliminary evaluation of an electromagnetic three-dimensional digitizer in facial anthropometry.

OBJECTIVE: In this investigation, the precision of a commercial three-dimensional digitizer in the detection of facial landmarks in human adults was assessed. METHODS: Fifty landmarks were identified and marked on the faces of five men, on five women, and on a stone cast of the face of one man. For each subject, the three-dimensional coordinates of the landmarks were obtained twice using an electromagnetic three-dimensional digitizer, and the duplicate digitizations were superimposed using common orientations and centers of gravity. Metric differences between homologous landmarks were assessed, and Dahlberg's error was computed. RESULTS: For both men and women, the error was 1.05% of the nasion-midtragion distance, while for the cast, it was 0.9%. When the duplicate digitizations were used to mathematically reconstruct the faces, and several distances, angles, volumes, and surfaces were computed, more than 80% of the measurements had coefficients of variation lower than 1%. CONCLUSIONS: The digitizer can assess the coordinates of facial landmarks with sufficient precision, and reliable measurements can be obtained.

Adult↗

PubMed1998

Quantitative description of the morphology of the human palate by a mathematical equation.

OBJECTIVE: To derive a three-dimensional mathematical description of normal human hard tissue palatal size and shape. METHODS: The maxillary dental casts of 30 adolescents free from respiratory problems, who had a complete (28 teeth) permanent sound dentition with normal occlusion, were studied. The x, y, z coordinates of several standardized palatal and dental landmarks were obtained with a computerized three-dimensional digitizer. Palatal landmarks were used to derive a mathematical equation of palatal shape in the frontal and sagittal planes. Palatal width, length, frontal and sagittal heights, and sagittal slope, as well as dental arch transverse and anteroposterior dimensions, were computed. RESULTS: Neither the size nor the shape of the palate was significantly influenced by gender. Only the intercanine distance was larger (p < .025) in males than in females. CONCLUSIONS: Data collected in the present investigation could represent a first database for the quantitative description of normal human palatal morphology in subjects with a complete permanent dentition.

Adolescent↗

PubMed1998

A morphometric approach to the study of human ovarian organogenesis.

This study deals with the morphometric approach used to describe the quantitative characteristics of human ovaries during their final histogenesis. Fixed ovaries ranging from the 20th fetal week to the 8th postnatal month were used. They were measured using a high precision caliper, were embedded in toto in epoxide resin, and systematically cut (1 microm-thick sections) orthogonal to the major axis of the organ. The surface areas were automatically measured, at low magnification, and ovarian volume was calculated using the Cavalieri method. The volume fractions of ovarian medulla, primitive cortical tissue, primordial, primary, secondary and Graafian follicles, and stroma were calculated by differential point counting at higher magnification. At the same magnification, the position of the different follicle categories in the cortex was estimated as percentage distance of the follicle from the cortico-medullary boundary. The number in unit cortex volume of the oocyte nuclei in primordial and primary follicles were derived by diameter analysis according to the Schwartz-Saltykov method, and the total follicle number for each ovary was obtained. The diameter of nuclear, cellular and follicular profiles of primary and primordial follicles in sections was also measured. Ovarian volume was about 30 mm3 at 20 fetal weeks and 287 mm3 at the 8th postnatal month, with a 9.5-fold increment. Irrespective of age, the cortex occupied most of the organs, ranging from 90% at 20 prenatal weeks (about 27 mm3) to 85% at 8 postnatal months (about 245 mm3). In the cortex, the interstitium or stroma intermingled with the germinal component: primitive cortical tissue was found in all ovaries, and its absolute volume remained unmodified between the 20th fetal week and birth. In the analyzed fetal stages, the total number of primordial follicles had its largest modification, with a 1.3-fold increment between the 20th-25th fetal weeks. Hereafter, the number increased at a slower rate (about 1.2 times between the 25th week and birth, 1.1 times between birth and the 8th postnatal month). The largest absolute volume of primordial follicles was found at birth. Follicular, oocyte and nuclear diameters increased during the intrauterine life, while after birth their dimensions did not modify further. Conversely, their spatial position in the cortex modified even after birth. In the 8-month old child nearly all germinal cells were comprised into follicles in different degrees of development, and the primitive cortical tissue was exhausted. A three-dimensional geometrical model of human ovary has also been elaborated to define the spatial organization of ovarian germinal and somatic components, and to allow the comparison of the present data to the "in-vivo" volumetric assessments.

Embryonic and Fetal Development↗

PubMed1998

Reliability of soft tissue references for anteroposterior measurement of dental bases.

The aims of the present investigation were to devise a new anteroposterior measurement of maxillomandibular discrepancies that would consider both hard and soft tissue contributions, and to verify the correlation of this measurement to a well-established linear assessment of anteroposterior discrepancy. On the pretreatment lateral cephalographs of 300 orthodontic patients (162 males, 138 females) aged between 6 and 50 years, the Wits appraisal and a new "soft tissue" Wits appraisal (linear distance between the projections of soft tissue A and B points on the bisecting occlusal plane) were measured. In the analyzed sample, the former was more variable than the latter. The two measurements were significantly correlated to each other without sex- or age-characteristic patterns. From the correlation, reference values for the new measurement were estimated and found to be between -1.9 mm and 5.4 mm for individuals with a normal occlusion. The new measurement could allow a more careful evaluation of the soft tissue drape together with the underlying hard tissue structure.

Adolescent↗

PubMed1997

Statistical evaluation of Monson's sphere in healthy permanent dentitions in man.

The three-dimensional curvature of the mandibular dental arch was studied in 20 men and 20 women with sound dentitions and free from temporomandibular joint problems. The x, y, z coordinates of cusp tips of all but the third molars were obtained with a three-dimensional digitizer, and used to derive a spherical model of the curvature of the occlusal surfaces. From the best interpolating sphere the radii of the left and right curves of Spee (quasi-sagittal plane) and of the canine and molar curves of Wilson (frontal plane) were computed. The occlusal curvature of the mandibular arch was not significantly influenced by gender, even if, on average, all the computed variables were larger in men than women. The radii of the overall sphere, right and left curves of Spee, and curve of Wilson in the molar area were about 105 mm in men, and about 100 mm in women. A relatively large intrasample variability in arch curvature was found. The mean sphere radius in men was very close to the classical value of 4 in, confirming Monson's observations, but the relatively large intrasample variability prevented any definitive determination of a sexual dimorphism in the three- dimensional characteristics of occlusal curvature.

Adult↗

PubMed1997

A size-standardized analysis of soft tissue facial profile during growth.

A method for the quantitative and qualitative analysis of the facial soft tissue profile has been developed and applied to analyze the age differences in lateral cephalograms for the annual Bolton standards from ages 1 to 18 years. To standardize for different facial sizes, profiles were traced in polar coordinates without modifications of facial shape. Most of the soft tissue landmarks showed progressive modifications from birth to 18 years of age. Soft tissue nasion and lower lip had a steep change between 2 and 3 years of life, pronasale between 3 and 5 years of life, A', upper lip, and stomion between 4 and 5 years of life. Hereafter, all these landmarks but N' had several minor modifications progressing toward the adult value. Soft tissue nasion did not modify significantly after 2 years of age. Conversely, changes in the relative positions of B' and Pg' were more scattered in the analyzed period. Age-related size differences were more linear than shape modifications, with gradual increments from 1 to 18 years of age. The method allowed a simple and rapid quantitative evaluation of soft tissue profiles during facial growth. An approximate evaluation of the soft tissue thickness at nose, lips, and chin was also possible. No particular mathematical knowledge was required at any step of the analysis. Results were in good agreement with the well-known patterns of normal growth and development, thus confirming the practical possibilities of the method.

Adolescent↗

PubMed1997

A three-dimensional non-invasive study of head flexion and extension in young non-patient subjects.

Head flexion and extension movements near the natural head position (NHP) were analysed for the location of the mean instantaneous centre of rotation (ICR). Forty-six healthy young adults (30 women and 16 men) with sound dentitions, free from cranio-cervical disorders, performed habitual movements that were automatically detected and measured by an infrared three-dimensional motion analyser. ICR and curvature radius were calculated for each movement and subject. In both extension and flexion, ICR position changed during the motion. The movement was symmetrical in all subjects. No gender or flexion/extension differences were found for both ICR position and relevant curvature radius. On average, ICR relative to NHP soft-tissue nasion was located at about 150% of the soft-tissue nasion-right tragus distance, with an angle of about 220 degrees relative to the true horizontal. Results suggest that head flexion or extension is always performed with a combination of rotation (atlanto-occipital joint) and translation (cervical spine) even in the first degrees of motion. Moreover, NHP at rest seems to be some degree more flexed and anterior than head position during movements. These relative positions and their muscular determinants could also influence mandibular posture at rest and during functional movements.

Adult↗

PubMed1997

Effect of growth and development on cephalometric shapes in orthodontic patients: a Fourier analysis.

The age- and gender-related shape variations of the craniofacial skeleton in skeletal Class I children were quantified using a Fourier analysis on the pre-treatment lateral head films of 122 orthodontic patients (age range 7-15 years), who were subdivided into six groups for sex and age (2-year intervals). Seven landmarks representative of the maxillo-mandibular sagittal and vertical relationship were identified and digitized. The contiguous landmarks were connected by segments, the form was normalized with respect to its orientation and size, and a Fourier analysis of the contour was performed. Mean values of the cosine and sine coefficients of the first six harmonics in the sex and age classes were computed. The size-standardized outlines of the oldest boys were narrower and longer than the outlines of the youngest boys (differences at gonion, menton, sella and nasion). Shape differences between mean plots in girls were negligible. In the youngest patients, girls had a larger size-independent shape in the mandibular region; their shape was narrower (anterior-posterior direction) and longer (vertical direction) than male shape. In the oldest patients, boys had a larger size-independent shape at gonion, and a narrower shape at articulare and pogonion than girls. Size increased from the youngest to the oldest boys; size differences were not conspicuous in girls. Within an age class, male size was always larger than female. Fourier analysis allowed a global evaluation of the cephalometric forms, with separate quantifications of the age- and gender-related differences in size and shape.

Adolescent↗

PubMed1997

Asymmetry of normal mandibular condylar shape.

Morphological studies of the facial skeleton in human beings are usually made from radiographs (frontal and lateral projections and orthopantomographs). The conventional linear and angular measurements provide quantitative information only about size, and fail to define the shape and form of the skeletal features and their variations. Mathematical methods such as the Fourier series allow a correct quantitative analysis of the shape and its variations. The outlines of the mandibular condyles in the orthopantomographs of 20 men and 20 women (mean age 29 years) were traced and digitized. All subjects had a good dentition, no temporomandibular joint problems, and were referred to a dental surgery for periodontal problems. A Fourier analysis of the outlines was performed. Fourier coefficients and reconstructed outlines were compared to analyze the condylar symmetry of shape on an intra- and intersubject basis. A significant condylar asymmetry for shape as distinct from size was found on an intrasubject basis, i.e. the left and right condyles of a single individual had a different shape with a large interindividual variability. Conversely, the mean condyle shape of the male and female groups was symmetric.

Adolescent↗

PubMed1997

Three-dimensional study of growth and development of the nose.

OBJECTIVE: The aim of this study was to describe normal nasal growth in a large sample of boys and girls from 6 to 14 years of age, to compare nasal development at 14 years of age with its adult dimensions, and to evaluate differences in growth patterns between males and females. DESIGN: Growth and development of the nose were analyzed through the three-dimensional facial morphometry method. One thousand thirteen examinations were performed on 402 children between 6 and 14 years of age and on 101 adults. Three-dimensional coordinates of five nasal landmarks were collected. Eleven parameters including nasal volume and external surface were calculated and averaged for age and sex. RESULTS: Volume, surface, and linear distances were larger in males than in females, with the exception of the 11-to-12 age group, where a sharp female growth spurt was present. In males, the growth spurt was broader, and continued to 13 years of age at a nearly steady rate. Statistically significant gender differences could be found both in the adult group and before the adolescent growth spurt. CONCLUSIONS: Our findings are in general agreement with previous reports on craniofacial growth, which suggested a strong tendency in males for growth to continue for several years beyond that seen in females.

Adolescent↗

PubMed1997

Size and shape of soft-tissue facial profile: effects of age, gender, and skeletal class.

OBJECTIVE: A method for the quantitative and qualitative analysis of the facial soft-tissue profile has been developed, and applied to analyze the pretreatment lateral head films of 240 orthodontic patients aged 8 to 14 years. METHODS: Patients were subdivided for sex, age, and skeletal class. To standardize for different facial sizes, soft-tissue profiles from nasion to pogonion were traced in polar coordinates without modifications of facial shape, and standardized for an equal skeletal vertical dimension. RESULTS: The method allowed a simple and rapid quantitative evaluation of soft-tissue profiles during facial growth. An approximate evaluation of the soft-tissue thickness at nose, lips, and chin was also possible. No particular mathematical knowledge was required at any step of the analysis. CONCLUSIONS: Facial soft-tissue size and shape were influenced by age and sex, and to a minor extent by skeletal class.

Adolescent↗

PubMed1997

The relationship between facial 3-D morphometry and the perception of attractiveness in children.

The aim of this investigation was to determine whether attractive children differ in their three-dimensional facial characteristics from nonattractive children of the same age, race, and sex. The facial characteristics of 36 boys and 44 girls aged 8 to 9 years were investigated. Frontal and profile photographs were analyzed independently by 21 judges, and, for each view, four groups were obtained: attractive boys, nonattractive boys, attractive girls, and nonattractive girls. For each child, the three-dimensional coordinates of 16 standardized soft tissue facial landmarks were automatically collected using an infrared system and used to calculate several three-dimensional angles, linear distances, and linear distance ratios. Mean values were computed in the eight groups, and attractive and nonattractive children were compared within sex and view. Most children received a different esthetic evaluation in the separate frontal and profile assessments; concordance in both attractive and nonattractive groups was only 50%. Moreover, three-dimensional facial morphometry was not able to separate attractive and nonattractive children.

Adult↗