Soft-Tissue Mobility of the Lower Face Depending on Positional Changes and Age: A Three-Dimensional Morphometric Surface Analysis

The Accuracy of Three-Dimensional Soft Tissue Simulation in Orthognathic Surgery-A Systematic Review

Three-dimensional soft tissue simulation has become a popular tool in the process of virtual orthognathic surgery planning and patient-surgeon communication. To apply 3D soft tissue simulation software in routine clinical practice, both qualitative and quantitative validation of its accuracy are required. The objective of this study was to systematically review the literature on the accuracy of 3D soft tissue simulation in orthognathic surgery. The Web of Science, PubMed, Cochrane, and Embase databases were consulted for the literature search. The systematic review (SR) was conducted according to the PRISMA statement, and 40 articles fulfilled the inclusion and exclusion criteria. The Quadas-2 tool was used for the risk of bias assessment for selected studies. A mean error varying from 0.27 mm to 2.9 mm for 3D soft tissue simulations for the whole face was reported. In the studies evaluating 3D soft tissue simulation accuracy after a Le Fort I osteotomy only, the upper lip and paranasal regions were reported to have the largest error, while after an isolated bilateral sagittal split osteotomy, the largest error was reported for the lower lip and chin regions. In the studies evaluating simulation after bimaxillary osteotomy with or without genioplasty, the highest inaccuracy was reported at the level of the lips, predominantly the lower lip, chin, and, sometimes, the paranasal regions. Due to the variability in the study designs and analysis methods, a direct comparison was not possible. Therefore, based on the results of this SR, guidelines to systematize the workflow for evaluating the accuracy of 3D soft tissue simulations in orthognathic surgery in future studies are proposed.

Age-related changes of the periocular morphology: a two- and three-dimensional anthropometry study in Caucasians

PURPOSE

To determine age-and sex-related changes in periocular morphology in Caucasians using a standardized protocol.

METHODS

Healthy Caucasian volunteers aged 18-35 and 60-90 years old were recruited from the Department of Ophthalmology, Faculty of Medicine and University Hospital, Cologne, between October 2018 and May 2020. Volunteers with facial asymmetry, facial deformities, history of facial trauma, facial surgery, botox injection, eyelid ptosis, strabismus, or nystagmus, were excluded. Standardized three-dimensional facial photos of 68 young volunteers and 73 old volunteers were taken in this clinical practice. Position changes of endocanthion, pupil center, and exocanthion were analyzed in different age and gender groups, including palpebral fissure width (PFW): distance between endocanthions (En-En), pupil centers (Pu-Pu), exocanthions (Ex-Ex), endocanthion and nasion (En-Na), pupil center and nasion (Pu-Na), exocanthion and nasion (Ex-Na), endocanthion and pupil center (Pu-En), exocanthion and pupil center (Pu-Ex), and palpebral fissure inclination (PFI); angle of endocanthions to nasion (En-Na-En), pupils to nasion (Pu-Na-Pu), exocanthions to nasion (Ex-Na-Ex); endocanthion inclination (EnI), and exocanthion inclination (ExI).

RESULTS

PFW, En-En, Ex-Na, Pu-Ex, PFI, ExI, and Ex-Na-Ex were significantly different between the young and old groups (p ≤ 0.004). There were sex-related differences in PFW, Ex-Ex, En-Na, Pu-Na, Ex-Na, Pu-En, PFI, and EnI between both groups (p ≤ 0.041).

CONCLUSION

The position change of the pupil is minimal relative to age; it is preferred to establish the reference plane to describe periocular changes. The endocanthion tends to move temporally and inferiorly, while the exocanthion tends to shift nasally and inferiorly with age.

Positional deformation of the parotid gland: application to minimally invasive procedures

Anatomical studies of the parotid gland are important for mid- and lower face filler, botulinum toxin, and thread lifting procedures. The purpose of this study was to observe the topographic anatomy of the parotid gland using cadaveric dissections. The superficial lobe of the parotid gland was studied in 30 hemisected heads. Reference lines were made on the lateral aspect of the face. A reference line (the line connecting the mandibular angle to the upper margin of the zygomatic arch, along the posterior border of the ramus) was divided into four sections (P1, P2, P3, and P4). The superior, inferior, anterior, and posterior borders of the parotid gland were measured using the reference lines and sections. Using these measurements, we categorized the superficial lobe of the parotid gland into two types: type Ia, pistol-shaped; Ib, pistol-shaped with an accessory lobe; and type II, oval-shaped. The superior border of the parotid gland started just below the inferior margin of the zygomatic arch. The parotid gland covered the posterior part of the masseter muscle near P1 and P2, but at P3 and below P3, the tail of the parotid gland was located posterior to the ramus and covered the anterior part of the sternocleidomastoid muscle. The topographic anatomy of the parotid gland serves as a reliable reference for esthetic procedures in the lower face and neck region. This article is protected by copyright. All rights reserved.

Quantitative Mobility Analysis of the Face and its Relevance for Surgical and Non-surgical Aesthetic Facial Procedures

BACKGROUND

Understanding the degree of facial mobility upon postural changes is of great clinical relevance especially if facial assessment, facial measurements and/or facial markings are done in an upright position, but facial procedures are performed in a supine position.

OBJECTIVE

The objective of this study is to investigate regional facial skin displacement and facial volume changes in individuals between upright and supine positions.

METHODS

This multi-center study analyzed a total of 175 study participants with a mean age of 35.0 (10.2) years and a mean body mass index of 24.71 (3.5) kg/m². 3D surface scanning technology with automated registration and alignment was utilized, and multivariate analyses were performed with adjustment for age, gender, body mass index, facial skin sagging and laxity.

RESULTS

The medial face displaced less than the lateral face in both cranial (0.88 mm) and in lateral (0.76 mm) directions, and the lower face displaced more than the middle face in both cranial (1.17 mm) and lateral directions (1.37 mm). Additionally, the medial face lost, on average, 3.00cc whereas the lateral face increased by 5.86cc in volume; the middle face increased by 2.95cc, whereas the lower face decreased by 0.98cc in volume. All p < 0.001.

CONCLUSION

Practitioners should be mindful that there is a statistically significant change in facial soft tissues between the upright and supine positions and that the magnitude of the change does not necessarily reflect on the aging process alone but is a multi-factorial process which should be individualized for each patient's needs.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Morphological Changes in Faces Depending on Posture

Facial surgeries are usually performed with the patient in the supine position; however, it is crucial to predict postoperative results in the upright position. This study aimed to clarify the posture-related morphological changes in the facial soft tissue regarding age and sex, using physical measurements to obtain results in specific linear metric measurements of standard facial features. One hundred healthy volunteers were divided into four groups based on age and sex (25 young men, 25 young women, 25 old men, 25 old women). For all participants, 18 measuring points were marked on the skin along with 18 paired linear measurements, and the angle was measured using a digital sliding caliper and angle meter in both upright and supine positions. In all four groups, the intercanthal width (en-en), binocular width (ex-ex), length of the eye fissure (en-ex), length of the nasal bridge (n-prn), width of the nose (al-al), height of the lower face (sn-gn), vermilion height of the lower lip (sto-li), height of the lower lip (sto-sl), width of the philtrum (cphi-cphi), width of the mouth (ch-ch), and nasolabial angle (NLA) were significantly larger in the supine position than in the upright position. The increase was larger in the older age groups than in the younger age groups. Moreover, the increase was larger in old men than in old women. During facial surgery involving these areas, surgeons should consider the patient's age and sex and understand what facial figuration change would occur depending on posture and change their preoperative design or make minor adjustments during operation in the supine position to increase patient satisfaction.

A comparison of postoperative, three-dimensional soft tissue changes in patients with skeletal class III malocclusions treated via orthodontics-first and surgery-first approaches

The aim of this retrospective study was to compare three-dimensional (3D) soft tissue and hard tissue changes between orthodontics-first approach (OFA) and surgery-first approach (SFA) after mandibular setback surgery. All patients underwent bilateral sagittal split osteotomy, and were examined by lateral cephalograms and 3D optical scanner before surgery (T0) and 1 (T1), 3 (T2), and 12 (T3) months after surgery. Three standard angles (FMA, U1 to FH, IMPA) were measured as hard tissue change and the 2 sets of 3D data were superimposed, and volumetric differences were calculated as soft tissue change. Statistical analyses were performed by using unpaired t-tests. Differences with P < 0.05 were considered significant. A total of 39 patients with mandibular prognathism were included in this study. The OFA group consisted of 24 patients and the SFA group of 15 patients. The SFA group exhibited more labial inclination from T1 to T2 (p = 0.008) and T2 to T3 (p = 0.003) than did the OFA group. There were no significant changes at maxilla and mandible at each term of T0, T1, T2 and T3 (p > 0.05), but compared to before surgery, mandibular volume in SFA group significant increased at 1year (p = 0.049) after surgery. We found that the soft tissue changes after the SFA differed significantly from those after the OFA; thus, soft tissue predictions require more care. An analysis of our data compared with OFA and SFA for the patient with mandibular prognathism confirm that the mandibular soft tissue changes by postoperative orthodontic treatment and occlusal relationship in SFA.

Anthropometric Changes in the Upper Lip Between the Standing Position in the Clinic and Supine Position on the Operative Table in Secondary Cleft Lip Nasal Deformities

BACKGROUND

We evaluated changes in lip height and length by position in cleft lip nasal deformity patients who underwent treatment with Millard technique.

METHODS

A retrospective review of the medical records and an anthropometric analysis of photographs were performed in 209 cases of cleft lip nasal deformity. In the photogrammetric analysis, the lip height and length were calculated with respect to the intercanthal width. To evaluate the change in the difference between the cleft- and noncleft-side measurements between the standing and supine positions, the difference between the cleft- and noncleft-side measurements (Δnc-c) was calculated. We identified which patients and surgical factors affected the difference between the cleft- and noncleft-side measurements between the standing and supine positions (Δst-sp).

RESULTS

From a total of 120 cases, cases with missing medical charts and clinical photographs were excluded, and 89 cases were included in this study. The discrepancy between the cleft-side lip height and noncleft-side lip height was significantly different between the standing and supine positions (P = 0.007). According to the univariate regression analysis, Δst-sp (sbal-cphi) had a significant positive correlation with body mass index (P = 0.044). In the final multiple linear regression analysis, body mass index had a significant positive correlation with Δst-sp (sbal-cphi, P = 0.044).

CONCLUSION

In our results, the difference in vertical lip height is easy to underestimate in the supine position during surgery. Therefore, surgeons should verify lip height with the patient in the sitting or standing position during the operation to avoid undercorrecting lips with short heights.

Facial soft tissue depth measurements in cone-beam computed tomography: A study of a Brazilian sample

Forensic facial reconstruction (approximation) (FFR) is an aid to human identification when no presumed identity is available. It is based on average soft tissue thickness (STT) applied onto a skull. These averages vary at each landmark according to sex, ancestry, and Facial Growth Patterns (FGP). To obtain the reference, there are different protocols and conditions, such as needles in cadavers, ultrasound, magnetic resonance, and computer tomography. Using cone-beam computed tomography (CBCT), landmark placement and direction of measurement are critical. The purpose of this article is to detailly describe a method for STT measurement in CBCT DICOM files and to test it in the analysis of a multi-ancestral Brazilian sample, subdivided into sex, age and FGP. A sample of 100 (50 male and 50 female) CBCT exams were selected and the volume was primarily been repositioned to cephalometric standards. A detailed description of the location and measurement direction of 32 landmarks was provided and granted good reproducibility of the measurements. The averages were assessed by sex, age, and FGP. There were significant differences between males and females. The CBCT measuring protocol provided standardization of measurements and is a method to be used in future researches. Advantages of CBCT, such as the subject's upright position and adjustable volume positioning, also justify its usage. Limited differences of STT were related to age and FGP. The updated Brazilian soft tissue thickness chart is a reliable source of data for forensic and clinical purposes.

Gravity in Midfacial Aging: A 3-Dimensional Study

BACKGROUND

Volume loss and volume descent are complementary aspects of facial aging, although the respective contribution of each is unclear.

OBJECTIVES

The aim of this study was to quantify in 3 dimensions the effects of gravity on the midface in both upright and supine positions in an older and a younger group of patients.

METHODS

A prospective study was undertaken of 53 female patients who had not undergone treatment with dermal fillers or facial cosmetic surgery. Three-dimensional photography with a VECTRA H1 camera (Canfield Scientific, Fairfield, NJ) was taken in supine and sitting positions. Volume shifts and displacement of structures in 3 dimensions were measured and analyzed.

RESULTS

Morphologically, upon shifting from sitting to supine position, the tail of the brow elevated, the tear trough filled, the buccal and malar fat shifted posteriosuperiorly, the earlobe decreased in height, the nasiolabial folds and marionette lines diminished, the modiolus shifted laterally, and the jowl diminished. Volumetric analysis revealed that the infraorbital region increased in volume by a mean [SD] of 0.59 [0.55] mL, the tear trough by 0.22 [0.19] mL, and the malar region by 1.2 [1.06] mL. With subjects in the supine position, all facial topographic landmarks displaced significantly from sitting position.

CONCLUSIONS

Facial aging in this cohort was predominantly due to tissue descent rather than volume loss. Reversal of the gravitational force restores the 3D position of the facial subunits and leads to volumization in desirable locations that approximates a more youthful appearance. The volume restored via redistribution of facial fat is comparable to that typically injected during direct volume transfer procedures.

LEVEL OF EVIDENCE: 4

Accuracy of three-dimensional virtual simulation of the soft tissues of the face in OrtogOnBlender for correction of class II dentofacial deformities: an uncontrolled experimental case-series study

Purpose

To assess whether virtual simulations of the projection of the soft tissues of the face after class II bimaxillary orthognathic surgery, generated from 3D reconstruction of preoperative computed tomography (CT) scans, differed significantly from the actual soft tissue profile obtained in the late postoperative period (beyond 6 months). Secondarily, to validate the accuracy of a free, open-source software suite for virtual soft tissue planning in orthognathic surgery.

Methods

Helical CT scans were obtained pre- and postoperatively from 16 patients with Angle class II malocclusion who underwent bimaxillary orthognathic surgery. A comparative study between soft tissue meshes constructed for surgical simulation (M1) and the actual meshes obtained from postoperative scans (M2) was then performed. To establish the accuracy of 3D facial soft tissue simulation in a free and open-source software suite (OrtogOnBlender-OOB), 17 predetermined anatomic landmarks were measured in M1 and M2 scans after alignment of cranial structures.

Results

The mean error between preoperative simulations and actual postoperative findings was < 2 mm for all anthropometric landmarks. The overall average error for the facial soft tissues was 1.07 mm.

Conclusion

Comparison between preoperative simulation (M1) and actual postoperative findings (M2) showed clinically relevant ability of the method to reproduce actual surgical movement reliably (< 2-mm error). OOB is capable of accurate soft tissue planning for orthognathic surgery, but mesh deformation methods still require improvement.

Trial registration

RBR-88jff9. Retrospectively registered at Brazilian Registry of Clinical trials-ReBec (http://www.ensaiosclinicos.gov.br) May 06, 2020.

Orbital Volume Increases With Age: A Computed Tomography-Based Volumetric Study

OBJECTIVE

The aim of the study was to determine whether the bony orbital volume (BOV) changes with age in males and females.

METHODS

This case-control study reviewed high-resolution (<1-mm slices) computed tomography (CT) scans of consecutive patients seen for 4 years. The scans were requested as part of the patient's routine care for symptoms related to sinus symptoms. Eligible participants were adults aged between 18 and 30 years and 60 and 75 years. Exclusion criteria included previous surgery, any medical conditions that might affect the bone or soft tissue of the orbit, and any abnormalities seen on imaging. Male patients aged between 18 and 30 years were compared with males aged 60 to 75 years. The same was done for females. The main outcome measure was measurement of the BOV. Both orbits of each patient were included using the generalized estimating equation, to avoid any bias from correlation between 2 orbits of the same patient.

RESULTS

A total of 240 orbits from 120 patients were used for this study. Each age group contained 30 patients. There were no significant differences in the ages between males and females in each age category (P = 0.88 for ages 20-30 years and P = 0.74 for ages 60-75 years). The mean (SD) BOV for females aged between 20 and 30 years was 19,153.69 mm (3776.21), whereas that for females aged between 60 and 75 years was 20,939.38 mm (2837.34). The difference between the groups was significant (Pr(>|W|) = 0.05). The mean (SD) BOV for males aged between 20 and 30 years was 22,2721 mm (2977.35), whereas that for males aged between 60 and 75 years was 22,892.92 mm (2389.46) (Fig. 1). The difference between these 2 groups was not significant (Pr(>|W|) = 0.40). The mean BOV was significantly greater for males than females (P ≤ 0.01) across both age groups.

CONCLUSIONS

This study found that female orbits expand with age, whereas male orbits showed no significant changes. Changes to the orbital volume in females may contribute to the appearance of aging.

Nose approximation among South African groups from cone-beam computed tomography (CBCT) using a new computer-assisted method based on automatic landmarking

Considering the high demand for the identification of unknown remains in South Africa, a need exists to establish reliable facial approximation techniques that will take into account sex and age and, most importantly, be useful within the South African context. This study aimed to provide accurate statistical models for predicting nasal soft-tissue shape from information about the underlying skull subtract among a South African sample. The database containing 200 cone-beam computer tomography (CBCT) scans (100 black South Africans and 100 white South Africans). The acquisition and extraction of the 3D relevant anatomical structures (hard- and soft-tissue) were performed by an automated three-dimensional (3D) method based on an automatic dense landmarking procedure using MeVisLab © v. 2.7.1 software. An evaluation of shape differences attributed to known factors (ancestry, sex, size, and age) was performed using geometric morphometric and statistical models of prediction were created using a Projection onto Latent Structures Regression (PLSR) algorithm. The accuracy of the estimated soft-tissue nose was evaluated in terms of metric deviations on training and un-trained datasets. Our findings demonstrated the influence of factors (sex, aging, and allometry) on the variability of the hard- and soft-tissue among two South African population groups. This research provides accurate statistical models optimized by including additional information such as ancestry, sex, and age. When using the landmark-to landmark distances, the prediction errors ranged between 1.769mm and 2.164mm for black South Africans at the tip of the nose and the alae, while they ranged from 2.068mm to 2.175mm for the white subsample. The prediction errors on un-trained data were slightly larger, ranging between 2.139mm and 2.833mm for the black South African sample at the tip of the nose and the alae and ranging from 2.575mm to 2.859mm for the white South African sample. This research demonstrates the utilization of an automated 3Dmethod based on an automatic landmarking method as a convenient prerequisite for providing a valid and reliable nose prediction model that meets population-specific standards for South Africans.

A 3D Morphometrical Evaluation of Brow Position After Standardized Botulinum Toxin A Treatment of the Forehead and Glabella

BACKGROUND

Botulinum toxin treatment for forehead wrinkles has been extensively studied and found to be a safe and reproducible procedure. However, the effect on the position of the eyebrows, which relies on the dynamic positioning of the treated muscles, has received less attention and has not been studied with 3-dimensional (3D) technology.

OBJECTIVES

The authors sought to evaluate the changes of eyebrow position after standardized botulinum toxin treatment of glabella or glabella and frontalis muscles with 3D imaging.

METHODS

In a prospective study, 2 groups of adult females were treated with botulinum toxin A at the glabella only (G) or at the glabella and the frontalis muscle (F/G). The brow position was measured at 5 positions with 3D photography before injection and 2 weeks, 3 months, and 6 months after injection. Results were statistically analyzed and related to patient age.

RESULTS

In the F/G group, the brow descended significantly almost across the whole brow length after 2 weeks. The descent lessened after 3 months and moved medially. No clear trend was evident in the G group. There was no significant change attributed to patient age in both groups.

CONCLUSIONS

Botulinum toxin treatment of the glabella and frontalis muscle impacts the position and configuration of the eyebrow. The degree of change is affected by the amount of frontalis weakening rather than by treatment of the glabella. While age in general is not a reliable predictor, individual factors play the major role in how pronounced a change of the brow can be expected.

LEVEL OF EVIDENCE: 2

Skeletal dimensions as predictors for the shape of the nose in a South African sample: A cone-beam computed tomography (CBCT) study

The profile of the nose is an important feature for facial approximations. Although several manual and semi-automated prediction guidelines exist for estimating the shape of the nose, the reliability and applicability of these methods to South Africans groups are unknown. The aim of this study was to predict the displacements of capulometric landmarks from hard-tissue planes to facilitate nasal soft-tissue reconstruction in a South African sample. Cone beam computed tomography (CBCT) scans of 120 adult South Africans were selected from the Oral and Dental Hospital, University of Pretoria, South Africa. Measurements involving craniometric and capulometric landmarks of the nose were obtained as plane-to-plane distances. Correlation coefficients between hard- and soft-tissue measurements were determined, and regression equations computed to assist in the prediction of the most probable shape and size of the nose. All hard- and soft-tissue measurements appeared significantly different between groups, except for the distance between the pronasale and nasion in the transverse plane and for the distance between the alare and the nasion in the coronal plane. The nasal height, nasal bone length and the nasal bone projection were significant predictors of the pronasale, subnasale and alare positions. More precisely, the nasal height and the nasal bone length were significant predictors of the pronasale position in both groups. Nasal bone projection was only useful for predicting shape in white South Africans. The variation in the skeletal predictors of the external shape of the nose noted between black and white South Africans and the results of the cross-validation testing emphasize the need for population specific guidelines.

Volumetric comparison of maxillofacial soft tissue morphology: computed tomography in the supine position versus three-dimensional optical scanning in the sitting position

OBJECTIVE

Three-dimensional (3-D) surgical simulation has become popular, but the accuracy of such simulation is difficult to assess. Because maxillofacial soft tissue profiles vary with posture, we compared such profiles obtained in the supine and sitting positions.

STUDY DESIGN

In total, 28 patients with skeletal Class III jaw deformities underwent computed tomography in the supine position and 3-D optical scanning in the sitting position. The 2 sets of 3-D data were superimposed, and linear and volumetric differences were calculated. We evaluated the cheeks, the subauricular and infraorbital regions, the nose, the lips, and the chin. Statistical analyses were performed by using paired Student's t tests. Differences with P < .05 were considered significant.

RESULTS

Patients were divided into 3 groups based on body mass index. The facial profiles of the cheeks and subauricular areas differed significantly between the sitting and supine positions. The extent of variation increased with body mass index.

CONCLUSIONS

When a patient moves from the sitting position to the supine position, maxillofacial soft tissue migrates from the cheeks to the subauricular regions. Thus, simulations for surgery based on supine computed tomography alone do not accurately model the cheeks and subauricular areas.

Age-Related Changes of the Orolabial Region in Caucasian Women: An Anthropometric Analysis

PURPOSE

Anthropometric data can provide valuable support for the attending physician in planning surgical and nonsurgical esthetic procedures with regard to a patient's age. The purpose of the present study was to identify age-related orolabial changes in younger and older Caucasian women.

MATERIALS AND METHODS

In the present cross-sectional study, anthropometric landmarks were identified using indirect anthropometry (2-dimensional photometry) in younger (≤35 yr) and older (≥50 yr) Caucasian women to analyze age-related parameters and proportions of the orolabial region, especially of the lower and upper lip vermilion areas. The Mann-Whitney U test was applied to compare the results between the younger and older populations.

RESULTS

The study population consisted of 45 women. The cohort was divided into a younger population (24 participants; mean age, 27.4 yr) and an older population (21 participants; mean age, 58 yr) to evaluate age-related differences. Increases of upper lip height, cutaneous height of the upper lip, and cutaneous height of the lower lip were observed in older women. In contrast, the vermilion height of the lower lip decreased significantly with increasing age.

CONCLUSION

These results show changes of the orolabial region occur in Caucasian women with increasing age. The statistically relevant decrease of the vermilion height of the lower lip should be given particular attention for (age-appropriate) diagnostic, esthetic, and prosthetic treatment planning.

Quantified Facial Soft-tissue Strain in Animation Measured by Real-time Dynamic 3-Dimensional Imaging

BACKGROUND

The aim of this study is to evaluate and quantify dynamic soft-tissue strain in the human face using real-time 3-dimensional imaging technology.

METHODS

Thirteen subjects (8 women, 5 men) between the ages of 18 and 70 were imaged using a dual-camera system and 3-dimensional optical analysis (ARAMIS, Trilion Quality Systems, Pa.). Each subject was imaged at rest and with the following facial expressions: (1) smile, (2) laughter, (3) surprise, (4) anger, (5) grimace, and (6) pursed lips. The facial strains defining stretch and compression were computed for each subject and compared.

RESULTS

The areas of greatest strain were localized to the midface and lower face for all expressions. Subjects over the age of 40 had a statistically significant increase in stretch in the perioral region while lip pursing compared with subjects under the age of 40 (58.4% vs 33.8%, P = 0.015). When specific components of lip pursing were analyzed, there was a significantly greater degree of stretch in the nasolabial fold region in subjects over 40 compared with those under 40 (61.6% vs 32.9%, P = 0.007). Furthermore, we observed a greater degree of asymmetry of strain in the nasolabial fold region in the older age group (18.4% vs 5.4%, P = 0.03).

CONCLUSIONS

This pilot study illustrates that the face can be objectively and quantitatively evaluated using dynamic major strain analysis. The technology of 3-dimensional optical imaging can be used to advance our understanding of facial soft-tissue dynamics and the effects of animation on facial strain over time.