The mouth and perioral area play a primary role in emotional expression and attractiveness of the face. Insight into the perioral aging process is key for the aesthetic surgeon to provide a comprehensive evidence-based therapeutic approach that fits the patients’ individual needs. Unfortunately, the mechanisms of centrofacial aging are poorly understood. The debate about facial sagging versus facial deflation is still ongoing. Many therapeutic strategies rely on assumptions, and so far, no single approach has risen to be the gold standard.
In the scientific literature, one can find numerous attempts to answer the question of how facial tissue ages over time. The maxillary bone, teeth, and mandible constitute the solid framework that defines the shape of the face. Bony resorption in the aging face is most profound at the maxillary level and at the alveolar ridge after tooth loss. The flattening of the maxillary arch causes a posterior displacement of the nasal base and upper lip and leaves a redundancy in the soft-tissue envelope of the perioral complex.1–3 Intrinsic soft-tissue changes are a thinning cutis from degradation of elastin and collagen fibers and distinct atrophy of the orbicularis oris muscle.4–6 Clinically, the upper lip undergoes vertical lengthening and appears deflated. Findings on photometric analysis have shown that older patients show significant lengthening of the upper lip with thinning of the vermillion, decrease of incisor show, and loss of anterior projection.7 , 8 Upper lip lengthening was also shown by Iblher et al. on cranial magnetic resonance imaging together with a significant thinning of the upper lip with age. Because their findings showed no volume loss, they claimed that the upper lip changes resulted from caudal redistribution of soft tissue instead of tissue loss.9 This conclusion conflicts with the widely adopted technique of volume augmentation to rejuvenate the upper lip.10–13 Such incongruences imply that more profound metric data on soft-tissue proportions are needed to understand the morphologic changes caused by facial aging. Unravelling these changes can provide the aesthetic surgeon with an evidence-based foundation for rejuvenation therapy. In this study, the soft tissue of the upper lip unit was measured on magnetic resonance images to evaluate the differences between young and old women and men. Figure 1 illustrates how the upper lip is displayed on these images and how differences are visually apparent between young and old individuals.
PATIENTS AND METHODS
The study group consisted of 200 patients who underwent cranial magnetic resonance imaging for intracranial abnormality. They were selected by age and sex from a general population, which eliminates the selection bias of patients who seek perioral rejuvenation therapy. Among them were 100 women and 100 men, each subdivided into two equal groups of 20 to 30 years old and 65 to 80 years old. The older group has a wider range because of the numerous edentulous patients. Exclusion criteria were edentulous patients and image artifacts from movement or orthodontic material. The images were selected from cranial magnetic resonance imaging scans obtained between January of 2010 and June of 2017 at the Department of Radiology of the University Hospital, Ghent, Belgium. These sagittal T1-weighed images were obtained with a 1.5-T magnetic resonance unit (Siemens, Erlangen, Germany). The use of these images and this study were approved by the institutional ethical committee, conforming to the Declaration of Helsinki.
Two hundred magnetic resonance images were retrospectively analyzed to obtain metric data of the upper lip and nasolabial fold. In the human face, the upper lip originates from the anterior nasal spine and nasal base and rests posteriorly on the upper dental row. The median sagittal section that contains these bony landmarks was systematically selected so a reproducible measuring method could be applied. To obtain a three-dimensional quantification of the tissue changes, the length and thickness of the upper lip were also measured on a parasagittal section. We selected the section that contained the most lateral portion of the nasal ala (Fig. 2).
The upper lip length was measured on sagittal section between the tip of the anterior nasal spine and the touching point between the upper and lower lip (Fig. 3). Perpendicular to this line, the thickness at the thickest portion (Fig. 3), the thinnest portion (Fig. 3), and the thickness at the vermiliocutaneous junction border of the lip (Fig. 3) were measured. On the cross-section of the upper lip, the surface area was measured as an indicator for upper lip volume (sagittal cross-section surface area) (Fig. 4). On the parasagittal sections, the dental axis served as a reference to make perpendicular measurements of soft-tissue thickness. The nasolabial tissue thickness was measured at the alar base. The lateral lip length was measured parallel to the dental axis. The lateral lip thickness was measured at the middle of this length (Fig. 5). Each bilateral parasagittal measurement was merged into one mean value. The difference in soft-tissue thickness between age groups was calculated for several locations in the lip, which allowed us to evaluate whether certain locations show significantly more difference than others. Anterior lip projection of the vermillion was called “pouting” and was calculated from a ratio between the thinnest portion of the lip and the thickness at the vermiliocutaneous junction. The calculated differences between age groups were then themselves compared for statistically significant differences between variables.
A power analysis was executed to determine the required study sample size. The obtained data were analyzed for statistical significance using IBM SPSS Version 2.25 (IBM Corp., Armonk, N.Y.) and results were registered as significant at a level of p < 0.01.
Statistical analysis of our data showed that all variables had a normal distribution. This allowed use of the t test to evaluate whether a statistically significant difference from the null hypothesis was apparent (the null hypothesis being that there are no significant metric changes in length, thickness, or volume of the upper lip between different age groups).
The mean age in the young group was 24.66 ± 2.69 years for women and 24.76 ± 2.51 years for men (range, 20 to 30 years). The mean age in the old group was 71.32 ± 3.29 years for women (range, 65 to 79 years) and 71.56 ± 3.12 years for men (range, 65 to 78 years). This covers a lifespan of approximately 47 years.
The lip length was measured on sagittal and parasagittal section and was significantly longer (p < 0.001) in the older age group in both sexes. The mean sagittal lip length was 19.70 percent (4.45 ± 0.52 mm) longer in women and 18.39 percent (4.51 ± 0.61 mm) longer in men. The mean parasagittal lip length was 11.59 percent (2.45 ± 0.42 mm) longer in older women and 12.14 percent (2.88 ± 0.50 mm) longer in older men (Table 1). The difference between age groups in sagittal lip length was significantly greater (p < 0.001) than the difference in parasagittal lip length in both sexes.
Lip Thickness and Pouting
Lip thickness was measured on three levels on sagittal section and on one level on parasagittal section. The upper lip showed a significant (p < 0.001) decrease in thickness on all levels compared between young and old female subjects and male subjects, with the highest percentage at the vermiliocutaneous junction: 40.55 percent (5.34 ± 0.32 mm) in women and 32.74 percent (4.57 ± 0.31 mm) in men. The smallest difference was found for parasagittal lip thickness: 19.68 percent (2.97 ± 0.28 mm) in women and 11.54 percent (1.63 ± 0.27 mm) in men (Table 2).
Pouting was calculated to objectify anterior projection of the vermillion. It is calculated as the tissue thickness at the vermiliocutaneous junction divided by the tissue thickness of the thinnest portion of the upper lip on sagittal section. Significantly less pouting was observed (p < 0.001) in older women [−13.71 percent (−0.17 ± 0.04)] and older men [−11.97 percent (−0.14 ± 0.03)] (Table 3).
Nasolabial Tissue Thickness
The nasolabial tissue thickness was significantly thinner in the older age group in both women (−25.7 percent) and men (−25 percent) (p < 0.001) (Table 4). The difference between age groups in nasolabial tissue thickness was significantly greater when compared to the difference in lateral lip tissue thickness in both sexes (p < 0.001).
The sagittal cross-section surface area was significantly smaller in the older age group in both sexes (p < 0.001). Women had an average difference of 20.89 percent and males had a difference of 17.40 percent (p < 0.001) (Table 5).
Women versus Men
Women have in general thinner soft tissue in the perioral region (up to 31.79 percent difference in older individuals) compared with men. There is slightly more pouting (5.64 percent) in young female subjects than in male subjects (p = 0.01), but this difference was not significant in the old age group (2.8 percent; p = 0.361). Men in both age groups have a significantly higher volume of the upper lip compared with women (p < 0.001).
Aesthetic surgeons proposed many theories in an attempt to unravel the dynamics of the aging face. Although genetics mostly determines how well soft tissues withstand aging and external damage, the extent of sun exposure, stress, hormones, and nicotine and alcohol use are known to contribute to the process as well.7 , 13–15 Folds and wrinkles deepen and sagging appears as the skin envelope loses elasticity. The contour of the face changes as the envelope’s content shrinks and shifts. As the current rejuvenation strategy contains soft-tissue repositioning and volume augmentation, aesthetic surgeons benefit from metric data on the changing proportions of the aging face. Even though this study examined unpaired groups, the percentages from compared averages can be used as a directive for individual therapy planning.
The association found in this study between an increase in length and thinning of the upper lip with older age confirms the clinical observation of this apparent feature of the aging face.7 , 9 , 15–19 The parasagittal portion of the lip was shown to be less affected by lengthening and thinning than the sagittal section, whereas the most profound thinning was observed at the vermiliocutaneous junction. This relates to our finding that there is significant loss of anterior projection (pouting) of the upper lip with age. Because the vermiliocutaneous junction contains the thickest portion of the orbicularis oris muscle (pars marginalis), there is a possible relation between senile muscle atrophy and the loss of pouting. This atrophy was shown by Penna et al. on histologic analysis, together with an increase in adipose subcutaneous tissue in the old upper lip. The significant difference in changes between sagittal and parasagittal measurements can be explained by the difference in mobility between these two planes. The sagittal section is subject to higher muscle tension and is therefore possibly more affected by fat resorption and ptosis. Although Iblher et al. failed to demonstrate a difference in volume on magnetic resonance imaging comparing two age groups,9 our results showed that the lengthening and thinning of the upper lip is more than a caudal redistribution of tissue and that volume loss is an obvious feature of the aging upper lip. Apparently, a larger study sample was required to reveal the volume loss in the aging upper lip.
Clinically, the aging upper lip becomes surrounded by deepening nasolabial folds. At the depth of this fold, there is a junction between two areas with different degrees of dermal adherence. The descending malar fat pad bulges over the firmer adhered area over the orbicularis oris muscle and creates a fold.20–22 The levator labii superioris alaeque nasi and levator labii superioris muscles insert into the orbicularis oris and thus suspend the firmly adhered area further underneath the bulging malar fat pad. Contraction of these muscles accentuates the fold,5 , 10 , 23 whereas the fold is relieved in patients with facial paralysis.24 In this study, a significant thinning of the soft tissue was found at the alar base where the levator labii superioris alaeque nasi muscle inserts into the orbicularis oris muscle. In addition, a more profound tissue loss was measured at this point when compared to the tissue loss in the parasagittal upper lip. This finding suggests the presence of influencing factors in this area that induce additional tissue loss.
This study revealed that soft-tissue proportions change in varying degrees at different points. This association between time and soft-tissue changes does not imply causality. In this manner, it does not contribute to answering the etiologic question of aging soft tissue. However, it does provide a clearer view for the aesthetic surgeon on how to combat the three-dimensional dynamic changes of the aging perioral area. To gain deeper understanding of these changes, and to determine whether the changes occur in a linear fashion over time or not, data from age groups in between those investigated in this study would be necessary. Although this might reveal certain associations (e.g., slope changes around menopause in women), the strongest association can only come from paired analysis. However, because magnetic resonance imaging was only introduced in 1977, the technology is not yet old enough to cover the 47-year lifespan investigated in this study.
Our results suggest that the aged perioral area is affected with variable degrees of soft-tissue lengthening, thinning, and volume loss. These findings contribute to a better understanding of the mechanics of aging in the perioral area. The implications of this study on perioral rejuvenating strategies are explained in part II.
1. Shaw RB Jr, Kahn DM. Aging of the midface bony elements: A three-dimensional computed tomographic study. Plast Reconstr Surg. 2007;119:675–681; discussion 682683.
2. Zadoo VP, Pessa JE. Biological arches and changes to the curvilinear form of the aging maxilla. Plast Reconstr Surg. 2000;106:460–466; discussion 467468.
3. Bartlett SP, Grossman R, Whitaker LA. Age-related changes of the craniofacial skeleton: An anthropometric and histologic analysis. Plast Reconstr Surg. 1992;90:592–600.
4. Rohrich RJ, Pessa JE. The anatomy and clinical implications of perioral submuscular fat. Plast Reconstr Surg. 2009;124:266–271.
5. Penna V, Stark GB, Eisenhardt SU, Bannasch H, Iblher N. The aging lip: A comparative histological analysis of age-related changes in the upper lip complex. Plast Reconstr Surg. 2009;124:624–628.
6. Penna V, Stark GB, Iblher N. Aging changes of the male lips: A lesser evil than in females? Ann Plast Surg. 2017;78:334–337.
7. Raschke GF, Rieger UM, Bader RD, et al. Perioral aging: An anthropometric appraisal. J Craniomaxillofac Surg. 2014;42:e312–e317.
8. Lambros V, Amos G. Three-dimensional facial averaging: A tool for understanding facial aging. Plast Reconstr Surg. 2016;138:980e–982e.
9. Iblher N, Kloepper J, Penna V, Bartholomae JP, Stark GB. Changes in the aging upper lip: A photomorphometric and MRI-based study (on a quest to find the right rejuvenation approach). J Plast Reconstr Aesthet Surg. 2008;61:1170–1176.
10. de Maio M, Wu WTL, Goodman GJ, Monheit G. Facial assessment and injection guide for botulinum toxin and injectable hyaluronic acid fillers. Plast Reconstr Surg. 2017;140:393e–404e.
11. Shue S, Kurlander DE, Guyuron B. Fat injection: A systematic review of injection volumes by facial subunit. Aesthetic Plast Surg. 2018;42:1261–1270.
12. Suryadevara AC. Update on perioral cosmetic enhancement. Curr Opin Otolaryngol Head Neck Surg. 2008;16:347–351.
13. Coleman SR, Grover R. The anatomy of the aging face: Volume loss. Aesthet Surg J. 2006;26(Suppl):S4–S9.
14. Weston GW, Poindexter BD, Sigal RK, Austin HW. Lifting lips: 28 years of experience using the direct excision approach to rejuvenating the aging mouth. Aesthet Surg J. 2009;29:83–86.
15. Guerrissi JO, Sanchez LI. An approach to the senile upper lip. Plast Reconstr Surg. 1993;92:1187–1191.
16. Lévêque JL, Goubanova E. Influence of age on the lips and perioral skin. Dermatology 2004;208:307–313.
17. Penna V, Stark GB, Voigt M, Mehlhorn A, Iblher N. Classification of the aging lips: A foundation for an integrated approach to perioral rejuvenation. Aesthetic Plast Surg. 2015;39:1–7.
18. Penna V, Fricke A, Iblher N, Eisenhardt SU, Stark GB. The attractive lip: A photomorphometric analysis. J Plast Reconstr Aesthet Surg. 2015;68:920–929.
19. Raphael P, Harris R, Harris SW. Analysis and classification of the upper lip aesthetic unit. Plast Reconstr Surg. 2013;132:543–551.
20. Yousif NJ, Gosain A, Matloub HS, Sanger JR, Madiedo G, Larson DL. The nasolabial fold: An anatomic and histologic reappraisal. Plast Reconstr Surg. 1994;93:60–69.
21. Perkins SW, Sandel HD IV. Anatomic considerations, analysis, and the aging process of the perioral region. Facial Plast Surg Clin North Am. 2007;15:403–407, v.
22. Naznin K, Ellis D. The lip-cheek groove. Arch Facial Plast Surg. 2017;8:324–328.
23. Wollina U. Perioral rejuvenation: Restoration of attractiveness in aging females by minimally invasive procedures. Clin Interv Aging 2013;8:1149–1155.
24. Rubin LR, Mishriki Y, Lee G. Anatomy of the nasolabial fold: The keystone of the smiling mechanism. Plast Reconstr Surg. 1989;83:1–10.