Reliability of optical devices for three-dimensional facial anatomy description: a systematic review and meta-analysis.

The use of three-dimensional (3D) optical instruments to measure soft tissue facial characteristics is increasing, but systematic assessments of their reliability, practical use in research and clinics, outcome measurements, and advantages and limitations are not fully established. Therefore, a review of the current literature was performed on the reliability of facial anthropometric measurements obtained by 3D optical facial reproductions as compared to conventional anthropometry or other optical devices. The systematic literature search was conducted in electronic databases following the PRISMA guidelines (PROSPERO registration: CRD42018085473). Overall, 815 studies were identified, with 27 final papers included. Two meta-analyses were conducted. Tested devices included conventional cameras, laser scanning, stereophotogrammetry, and structured light. Studies measured living people or inanimate objects. Overall, the optical devices were considered reliable for the measurement of linear distances. Some caution is needed for surface assessments. All instruments are suitable for the analysis of inanimate objects, but fast scan devices should be preferred for living subjects to avoid motion artefacts in the orbital and nasolabial areas. Prior facial landmarking is suggested to improve measurement accuracy. Practical needs and economic means should direct the choice of the most appropriate instrument. Considering the increasing interest in surface-to-surface measurements, fast scan devices should be preferred, and dedicated protocols devised.

Three-dimensional assessment of restored smiling mobility after reanimation of unilateral facial palsy by triple innervation technique.

The aim of this study was to assess surgically restored facial mobility using an optical 3D instrument. Eleven patients (age range 42-76 years) with unilateral facial palsy, treated by triple innervation procedure (masseteric and partial hypoglossal reinnervation, plus double cross-face facial grafting), performed five facial animations: rest position, smiling by contracting the healthy side, clenching the teeth, and pushing the tongue against the lower incisors and Mona Lisa smiling. These were recorded by stereophotogrammetry. Sixty healthy subjects were also recorded. The 3D reconstruction of each facial expression was registered onto the rest position scan, and the root mean square (RMS) point-to-point distance between the two 3D surfaces was calculated automatically for the facial thirds. RMS values on the rehabilitated hemiface were 74.8% (upper third), 46.6% (middle third), and 54.1% (lower third) of those recorded in healthy subjects. RMS values were higher in the middle and lower thirds than in the upper third, and during smile provided by masseteric stimulus (P<0.05). The rehabilitated hemiface differed more from healthy subject values than the healthy hemiface did (P<0.05). On average, patients were more asymmetric than healthy subjects (P=0.004). The proposed method is non-invasive and non-contact, and it can quantify localized facial movements after surgical procedures.

Three-dimensional longitudinal evaluation of facial mimicry in orthognathic class III surgery.

The effect of bimaxillary orthognathic surgery on facial mimicry was assessed longitudinally in 15 patients with dentoskeletal class III facial dysmorphism (seven men, eight women, mean age 28 years). The patients were analysed pre-surgery and at 6, 12, and 24 months post-surgery while performing verbal (five vowels) and non-verbal (open and closed mouth smile, lip purse) soft tissue facial movements. The three-dimensional motions of right and left nasogenian, crista philtri, cheilion, and lower lip landmarks were detected by an optoelectronic instrument, and a total mobility index was obtained. Differences between the sides were quantified by the symmetry index. Patient values were compared to those collected previously from healthy volunteers by computing z-scores. On average, no significant differences were found in the mobility of the buccal soft tissues at 24 months after surgery (ANOVA P-value, range 0.075-0.808), with positive median z-scores (pooled mean value close to 0.6). Symmetry indices ranged around the control reference values, showing no stage-related differences (Friedman test P-value, range 0.252-0.937), and exceeding 90% for all movements at 24 months after surgery. Bimaxillary osteotomy does not compromise facial mimicry in either verbal or non-verbal facial movements.

Three-dimensional superimposition for patients with facial palsy: an innovative method for assessing the success of facial reanimation procedures.

Facial palsy is a severe condition that may be ameliorated by facial reanimation, but there is no consensus about how to judge its success. In this study we aimed to test a new method for assessing facial movements based on 3-dimensional analysis of the facial surfaces. Eleven patients aged between 42 and 77 years who had recently been affected by facial palsy (onset between 6 and 18 months) were treated by an operation based on triple innervation: the masseteric to temporofacial nerve branch, 30% of the hypoglossal fibres to the cervicofacial nerve branch, and the contralateral facial nerve through two cross-face sural nerve grafts. Each patient had five stereophotogrammetric scans: at rest, smiling on the healthy side (facial stimulus), biting (masseteric stimulus), moving the tongue (hypoglossal stimulus), and corner-of-the-mouth smile (Mona Lisa). Each scan was superimposed onto the facial model of the "rest" position, and the point-to-point root mean square (RMS) value was automatically calculated on both the paralysed and the healthy side, together with an index of asymmetry. One-way and two-way ANOVA tests, respectively, were applied to verify the significance of possible differences in the RMS and asymmetry index according to the type of stimulus (p=0.0329) and side (p<0.0001). RMS differed significantly according to side between the facial stimulus and the masseteric one on the paralysed side (p=0.0316). Facial stimulus evoked the most asymmetrical movement, whereas the masseteric produced the most symmetrical expression. The method can be used for assessing facial movements after facial reanimation.

Surface electromyography before and after orthognathic surgery and condylectomy in active laterognathia: a case report.

BACKGROUND: Condylar hyperplasia is a rare bone disease characterised by excessive development of mandibular condyle, which can lead to the development of asymmetric facial deformity together with malocclusion, mandibular deviation, TMJ and masticatory musculoskeletal system dysfunction. There is not a treatment protocol universally accepted. In order to determine the correct management, treatment and intervention timing of these patients, morphological examinations should be coupled with functional assessments. CASE REPORT: In the present case report, morphological (bone scintigraphy; orthopantomography; posteroanterior and lateral cephalograms; 3D facial photographs) and functional (surface electromyography of masseter and temporalis muscles) quantitative data of a 20-year-old male patient affected by unilateral condylar hyperplasia are presented. The patient underwent a surgical treatment with high unilateral condylectomy associated to a maxillary Le Fort I osteotomy; as well as orthodontic treatment before and after surgery. Facial morphology and masticatory muscles activity were assessed before surgery and followed-up 6, 12 and 24 months after surgery. Twenty-four months after surgery, all electromyographic values were normal, and soft-tissue facial asymmetry was negligible at 3D assessment. CONCLUSION: Surface electromyography joins a set of clinical and morphological diagnostic tests that help the surgeon in planning the operation and managing the post-surgical patient.

3D evaluation of maxillary arches in unilateral cleft lip and palate patients treated with nasoalveolar moulding vs. Hotz's plate.

To compare the three-dimensional changes occurring in the maxillary arch during the use of modified pre-surgical nasoalveolar moulding (PNAM) and Hotz's plate. A clinical trial including 32 children with unilateral cleft lip and palate (UCLP), 16 treated with Hotz's plate and 16 with PNAM, was performed. Impressions of the maxillary arches were taken: A. prior to pre-surgical orthopaedics, B. before cheiloplasty and C. after cheiloplasty. Models were digitised using a stereophotogrammetric instrument, and geodesic distances were calculated: anterior, canine and posterior widths of the arch, and lengths and cleft depths of the larger and shorter segments. The time and treatment effects were assessed by two-factor anova. A significant effect of treatment was found for cleft depth at the larger segment: children treated with Hotz's plate had significantly deeper cleft than children treated with PNAM. All distances significantly changed during time: the anterior and canine widths decreased, while the posterior width, the lengths and depths of the cleft segments increased. Significant treatment per time interactions was found. The anterior and canine widths reduced more with PNAM between time points A and B while Hotz's treatment was more effective between B and C. The shorter segment depth increased more between B and C with PNAM, and between A and B with Hotz's plate. During pre-surgical orthopaedics, therapy with PNAM obtained the best results in reducing the width at the anterior segment of the cleft. This treatment gave a lower increase in cleft depth than treatment with Hotz's plate.

Alendronate impairs epithelial adhesion, differentiation and proliferation in human oral mucosa.

OBJECTIVE: This study aimed at evaluating from a morphological point of view the effects of alendronate (ALN), a widely used nitrogen-containing bisphosphonate for the chronic treatment of osteoporosis, on the oral epithelium of healthy keratinized human oral mucosa. Bisphosphonate-related osteonecrosis of the jaw is a well-known severe consequence, but the effects during chronic therapy on the oral soft tissues are still matter of debate. MATERIALS AND METHODS: Six women over 60 year-old undergoing treatment of osteoporosis with 70 mg per week of oral ALN (lasting at least 2 years) were recruited and compared with a gender and age-matched group (n = 6). Proliferation, apoptosis, intercellular adhesion and terminal differentiation (TD) were investigated by immunofluorescence. In parallel, ultrastructural analysis was carried out. RESULTS: By immunofluorescence, a statistically significant decrease in keratinocyte proliferation was detected in the oral epithelium of the ALN group without any sign of apoptosis, but accompanied by a reduction in desmoglein 1 and keratin 10 expressions. In the uppermost layers of the oral epithelium of the ALN group, thin desmosomes were visible by transmission electron microscopy. CONCLUSION: Our results show that epithelial adhesion, TD and proliferation are affected by ALN therapeutic doses in clinically healthy human oral mucosa.

A new 3-D tool for planning plastic surgery.

Face plastic surgery (PS) plays a major role in today medicine. Both for reconstructive and cosmetic surgery, achieving harmony of facial features is an important, if not the major goal. Several systems have been proposed for presenting to patient and surgeon possible outcomes of the surgical procedure. In this paper, we present a new 3-D system able to automatically suggest, for selected facial features as nose, chin, etc., shapes that aesthetically match the patient's face. The basic idea is suggesting shape changes aimed to approach similar but more harmonious faces. To this goal, our system compares the 3-D scan of the patient with a database of scans of harmonious faces, excluding the feature to be corrected. Then, the corresponding features of the k most similar harmonious faces, as well as their average, are suitably pasted onto the patient's face, producing k+1 aesthetically effective surgery simulations. The system has been fully implemented and tested. To demonstrate the system, a 3-D database of harmonious faces has been collected and a number of PS treatments have been simulated. The ratings of the outcomes of the simulations, provided by panels of human judges, show that the system and the underlying idea are effective.

Three-dimensional analysis of dentolabial relationships: effect of age and sex in healthy dentition.

Morphological changes in three-dimensional (3D) dentolabial relationships during ageing were assessed in healthy individuals. 38 subjects with healthy dentition were analysed. They were divided into a youthful group (21-34 years, mean 26 years, SD 4) and an older group (45-65 years, mean 53 years, SD 5). Stone labial and dental models were made, digitized and 3D virtual reproductions of dentolabial morphology were obtained. From the digital reconstructions, the relative positions of the labial commissure and of the maxillary dental clinical crowns in the vertical direction were obtained. Sex and age effects were compared using two-way analysis of variance. Lip position relative to the teeth was significantly different in youthful and older subjects (P<0.01). No statistically significant effects of sex in dentolabial relationship were demonstrated, but a sex×age effect was found in the anterior labial segments (P<0.05). The perioral soft tissues drop down in older subjects and the soft tissue descends on the entire labial arch. These differences may help the clinician when estimating, planning and evaluating surgical, orthodontic and prosthetic treatments.

Facial mimicry after conservative parotidectomy: a three-dimensional optoelectronic study.

Facial nerve paralysis is one of several possible complications following conservative parotidectomy. To assess three-dimensional facial movements non-invasively in patients with unilateral facial palsy following parotidectomy for benign tumours, the three-dimensional coordinates of 21 soft-tissue facial landmarks were recorded in 32 patients (21 HB I, 5 HB II, 6 HB III-IV; 3 months post-surgery follow-up), and 40 control subjects, during the performance of facial movements (smile, 'surprise', eye closure, single eye closure). For all symmetric animations, control subjects had larger total mobility than patients; mobility progressively decreased in patients with larger clinical grades. For asymmetric eye closures, HB I patients and control subjects had similar total movements, while HB II patients had smaller movements, especially for the paretic side eye closure; smaller total movements were found in HB III-IV patients. The method allowed the quantitative detection of alterations in facial movements. Significant differences between patients and control subjects in the magnitude and asymmetry of movements were found.

Three-dimensional analysis of labial morphology: effect of sex and age.

Morphological changes in the lips during ageing, including labial volume, area and thickness were assessed in healthy individuals. 40 healthy volunteers (20 men and 20 women) were selected and divided into two groups according to age: 21-34 years ('youthful' group) and 45-65 years ('aged' group). Three-dimensional (3D) stone labial models were made, digitized, and 3D virtual reproductions obtained. Labial thickness, vermilion area, and volume of the upper and lower lips were measured from the digital reconstructions. The data were compared using three-way ANOVA. All data were significantly larger in men than in women (p<0.05), the lower lip was thicker than the upper lip (p<0.001). A significant effect of age for labial thickness and area were found (p<0.001 and p=0.014): the youthful group had higher values than the aged group. Upper to lower lip ratios were not significantly different between sexes or ages. Generally, young people have a larger lip area and thickness than aged ones and men had larger lips than women. The upper/lower lip ratios for area and volume were similar in the two genders.

The effect of age and sex on facial mimicry: a three-dimensional study in healthy adults.

To assess sex- and age-related characteristics in standardized facial movements, 40 healthy adults (20 men, 20 women; aged 20-50 years) performed seven standardized facial movements (maximum smile; free smile; "surprise" with closed mouth; "surprise" with open mouth; eye closure; right- and left-side eye closures). The three-dimensional coordinates of 21 soft tissue facial landmarks were recorded by a motion analyser, their movements computed, and asymmetry indices calculated. Within each movement, total facial mobility was independent from sex and age (analysis of variance, p>0.05). Asymmetry indices of the eyes and mouth were similar in both sexes (p>0.05). Age significantly influenced eye and mouth asymmetries of the right-side eye closure, and eye asymmetry of the surprise movement. On average, the asymmetry indices of the symmetric movements were always lower than 8%, and most did not deviate from the expected value of 0 (Student's t). Larger asymmetries were found for the asymmetric eye closures (eyes, up to 50%, p<0.05; mouth, up to 30%, p<0.05 only in the 20-30-year-old subjects). In conclusion, sex and age had a limited influence on total facial motion and asymmetry in normal adult men and women.

Early epidermal response after a single dose of gamma-rays in organotypic culture of human breast skin.

BACKGROUND: Skin reaction is the most common side-effect of radiation therapy. Radiation-induced dermal fibrosis has been characterized histologically, but little is known about the epidermis overlying fibronecrotic lesions. OBJECTIVES: To characterize the epidermal response 24 h after a single clinically relevant dose of gamma-rays in cultured human breast skin. METHODS: Biopsies obtained from cosmetic surgery (n = 7) were placed epidermis upwards in a Transwell system, and were exposed to a single dose of gamma-irradiation (2 Gy). A parallel set of nonirradiated skin fragments was incubated under the same conditions. Both irradiated and nonirradiated fragments were harvested 24 h after irradiation and processed for light microscopy and molecular biology analysis. A quantitative analysis of cell proliferation was performed after 5-bromo-2'-deoxyuridine incorporation. Cytokeratin 10 (CK10) and desmocollin 1 (Dsc1) expression was evaluated by immunofluorescence. Dsc1 and transforming growth factor (TGF)-beta1 gene expression was measured by reverse transcriptase-polymerase chain reaction analysis. RESULTS: The mean percentage inhibition of epidermal proliferation in irradiated samples was 53.7% (P < 0.01, paired Student's t-test). The inhibition of cell proliferation was significant in five of seven samples (P < 0.05, unpaired Student's t-test). Normal cell architecture was found in irradiated samples. Throughout the epithelial compartment, the distribution patterns of CK10 and Dsc1 were comparable in nonirradiated and irradiated fragments. Condensation of CK10 filaments suggested a cytoskeletal rearrangement in irradiated samples. Dsc1 and TGF-beta1 mRNA levels were, respectively, reduced and unmodified 24 h after irradiation. CONCLUSIONS: A perturbation of epidermal homeostasis occurs as early as 24 h after a single dose of gamma-rays. Our immunofluorescence observations indicate that keratinocyte terminal differentiation is not yet affected at the protein level 24 h after exposure to gamma-rays. The lack of an inverse relationship between TGF-beta1 gene expression and epidermal proliferation, together with decreased Dsc1 gene expression, may represent the early molecular basis for the development of the late effects of radiotherapy observed many months/years after radiotherapy. Our findings set the stage for further investigation of the best time to begin topical treatment at the start of radiation therapy.

Morphometry of the ear in Down's syndrome subjects. A three-dimensional computerized assessment.

The three-dimensional coordinates of 13 soft-tissue landmarks on the ears were obtained by a computerized digitizer in 28 subjects with Down's syndrome aged 12-45 years, and in 449 sex, age and ethnic group matched controls. From the landmarks, left and right linear distances (ear width and length), ratios (ear width-to-ear length), areas (ear area), angles (angle of the auricle versus the facial midplane) and the three-dimensional symmetry index were calculated. For both males and females, all linear dimensions and areas were significantly (Analysis of Variance, P < 0.001) larger in the reference subjects than in the subjects with Down's syndrome. All values significantly increased as a function of age (P < 0.05); the increment was larger in the reference subjects than in the subjects with Down's syndrome. On both sides of the face, the subjects with Down's syndrome had larger ear width-to-ear length ratios, and larger angles of the auricle versus the facial midplane than the reference subjects. The three-dimensional symmetry index was significantly larger in the reference subjects and in the older persons. In conclusion, ear dimensions, position and shape significantly differed in subjects with Down's syndrome when compared to sex, age and ethnic group matched controls. Some of the differences were sex and age related.

Harmonic analysis of facial profiles: a 10-year evaluation.

A 10-year longitudinal evaluation was performed of the morphology of soft tissue facial profiles of 14 healthy adults (8 female and 6 male; mean age at the second evaluation, 34 years). 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 20-harmonic elliptic Fourier series expansion. Shape modifications were quantified by calculating the morphologic distance between the Fourier reconstruction of each facial profile in the 2 examinations. The area enclosed in each facial outline was automatically computed, and the difference between the soft tissue areas obtained in the 2 examinations was calculated. On average, significant longitudinal differences were found in both men and women for shape differences (P < 0.05), while size variations were significant only in men. While the 10-year increase in size was significantly (P < 0.01) larger in men than in women, no sex-related differences were found for shape modifications. Between the third and the fourth decades of life, both men and women experience some modifications in their facial soft tissues. While shape changes in both sexes, size changes are particularly evident in men and less manifest in women, who show greater variability in the amount of change that takes place.

Morphometry of the orbital region: a soft-tissue study from adolescence to mid-adulthood.

The objective of this study was to gain information about normal sex-related linear and angular dimensions of the orbital region; left-right symmetry; and growth changes between adolescence and mid-adulthood. The three-dimensional coordinates of several soft-tissue landmarks on the orbits and face were obtained by an electromagnetic digitizer in 40 male and 33 female adolescents aged 12 to 15 years, 73 female and 89 male young adults aged 19 to 30 years, and 41 male and 38 female adults aged 31 to 56 years. From the landmarks-binocular and intercanthal widths; paired height and inclination of the orbit relative to both the true horizontal (head in natural head position) and Frankfurt plane; length and inclination of the eye fissure; and the orbital height to eye fissure length ratio were calculated and averaged for age and sex. Comparisons were performed by factorial analysis of variance. Both the linear dimensions and the angular values were significantly larger in male subjects than in female subjects of corresponding age (p < 0.05). A significant effect of age was found (p < 0.05): while the linear distances and the orbital height-to-length ratio were greater in older people of the same sex, the inclination of the eye fissure decreased as a function of age. Both orbital inclinations were larger in the young adult group than in the adolescent and middle-aged groups. On average, the paired measurements were symmetrical, with similar values within each sex and age group. Data collected in this investigation could serve as a database for the quantitative description of human orbital morphology during normal adolescent and adult growth.

The effect of sex and age on facial asymmetry in healthy subjects: a cross-sectional study from adolescence to mid-adulthood.

PURPOSE: The study assessed the effects of sex and age on 3-dimensional (3D) soft-tissue facial asymmetry. PATIENTS AND METHODS: The 3D coordinates of selected soft-tissue facial landmarks were digitized on 314 healthy white subjects (40 male and 33 female adolescents, aged 12 to 15 years; 73 female and 89 male young adults, aged 18 to 30 years; and 41 male and 38 female adults, aged 31 to 56 years) by an electromagnetic instrument. Facial asymmetry was quantified by detecting a plane of symmetry and the centers of gravity of the right and left hemifaces and by calculating the distance between the 2 centers of gravity (distance from the symmetry [DFS]). Both absolute (millimeters) and percentage (of the nasion-center of gravity distance) DFS were obtained, as well as the maximum normal asymmetry. The asymmetry of single landmarks was also quantified. RESULTS: No gender- or age-related differences were found for both absolute and percentage DFS (P > .05). The maximum normal asymmetry was slightly greater in females than in males of corresponding age; within each sex, the largest values were found in the adolescent group. Tragion, gonion, and zygion were the most asymmetric landmarks in all groups (about 10% to 12% of the nasion-facial center of gravity distance), whereas the least asymmetric was endocanthion (4% to 6%). CONCLUSIONS: A slight soft-tissue facial asymmetry was found in normal subjects. The maximum normal asymmetry could be useful in identifying borderline asymmetric patients.