Age-related changes of jaws and soft tissue profile are important both for orthodontists and general dentists. Mouth profile is the area which is manipulated during dental treatment. These changes should be planned in accordance with other components of facial profile to achieve ultimate aim of structural balance, functional efficacy, and esthetic harmony. Through this paper, the authors wish to discuss age changes of the hard and soft tissues of human face which would help not only the orthodontists but also oral surgeons, prosthodontists, pedodontists, and general dentists.
Age-related changes of jaws and soft tissue profile are important both for orthodontists and general dentists. Behrents [
The increasing demand for adult orthodontics and orthognathic surgery increases the need to understand the facial aging process.
The physical anthropologists in earlier days worked with dry skull. Keith and Campion [
Hellman [
Broadbent [
Behrents [
The child has a high intellectual-like forehead without coarse eyebrow ridges, with prominent cheekbones, large and wide-set eyes, and a flat face. It has a short nose, low nasal bridge, and a concave nasal profile. The face is vertically short because of small nasal part, still growing jaw bones and not yet established primary and secondary dentition. Whether a young child’s head form is dolichocephalic or brachycephalic, the face itself appears more brachycephalic-like because it is still relatively wide and vertically short [
In a profile view, the most striking feature is lower jaw which is far retrusive than the face above. The general tendency seems to be for the mandible to grow from the more retruded to a less retruded position and this is usually true regardless of the individual facial type. The maxilla tends to be positioned in a forward direction much more slowly than does the mandible, resulting in a decrease in the convexity of the facial profile. This differential growth in an anterior direction determines the final facial type at the completion of growth [
The neurocranium grows earlier faster and to a much greater extent than facial complex. Cranial cavity completes 90% of its growth by 5 yrs of age. The young child’s forehead is upright and bulbous. This region seems very large and high because the face beneath it is still relatively small. But in the following years the face enlarges much more so that the proportionate size of the forehead becomes reduced. Pneumatization of the frontal sinus is responsible for the supraorbital ridges becoming prominent and forehead becoming much more sloping [
The young child has small rounded nose that protrudes very little and is vertically quite short. The nasal bridge is quite low with the lateral bony wall of the nose being characteristically narrow and shallow. The whole nasal region of the infant is vertically shallow and the nasal floor lies close to the inferior orbital rim. The shape of the nasal bridge changes from concave to convex [
Björk and Palling [
Longitudinal studies on postpubertal growth are limited. Slightly smaller jaw length increases were noted by Sarnas and Solow [
Postpubertal craniofacial skeletal and dental changes were examined from lateral cephalograms of Class I males taken when subjects were 16, 18, and 20 years of age by Love et al. [
Foley and Mamandras [
The mandibular plane angle decreased 1.1° during the age period of 14 to 20 years, suggesting a tendency for a closing rotation of the mandible. Mandibular incisors appeared to tip labially with advancing age. Although variable, the potential for significant maxillary and mandibular facial growth in females during late adolescence has been demonstrated.
The anterior outline of the bony maxillary arch in the infant has a vertically convex topography. This is in contrast to the characteristic concavity this region develops in the adulthood. The alveolar bone in this area of the adult face is noticeably protrusive. Anterior contour of premaxilla is flat in infants; the differential remodeling process draws out this contour [
Bishara et al. [
Kanekawa and Shimizu [
In mandibular arch, intercanine width increases between 3 and 13 yrs by 3.7 mm but decreases by 1.2 mm between 13 and 45 yrs. Intermolar width increases by 1.5 mm between 3 and 5 yrs and by 1 mm between 8 and 13 yrs but decreases by 1 mm by 45 yrs of age. There is a slight decrease in arch length with age because of uprighting of the incisors and loss of leeway space by the mesial movement of the first permanent molars [
Mandibular intercanine width, on the average, is established by 8 years of age, that is, after the eruption of the four incisors. After the eruption of the permanent dentition, the clinician should either expect no changes or a slight decrease in arch widths [
A longitudinal study of arch size and form in untreated adults was performed by Harris et al. [
The increase in anterior face height is probably largely due to continued tooth eruption. In females, the slight increase in the maxillary/mandibular plane angle may contribute to the increase in anterior face height. Sarnas and Solow [
In males, the posterior facial height increases by almost as much as the anterior face height. In females, the posterior face height does not increase significantly in contrast to the anterior face height. This accounts for the slight increase in the maxillary/mandibular plane angle. However, Bishara et al. [
The chin is incompletely formed in the infant. The mandible of the young child is quite small and retrusive relative to the upper jaw. The anterior cranial fossa is developmentally precocious. Hence, the nasomaxillary complex is carried to a more protrusive position. The mandible, which articulates on the middle cranial fossae, is located more posteriorly. With continuing growth, the chin tends to assume forward position relative to the superior aspects of the skeletal face and the mandible grows from the more retruded to a less retruded position [
The soft tissue nose is short, rounded, and pug-like. The nasal bridge is low; the nasal profile is concave and the nares can be seen in a face on view. It protrudes very little and is vertically quite short [
The human nose continues to grow in a downward and forward direction at least until early adulthood. There does not seem to be an appreciable decrease in the rate of nasal growth which is typical for the skeletal structures. Average yearly increase of 1–1.3 mm in the overall length of the external nose is almost the same for males and females.
In a longitudinal study, Behrents [
Chaconas [
Subtelny [
Wisth [
In the later stages of development, the nose usually becomes more inclined in a forward direction and the tip of the nose becomes more acute. Vertical dimension of the nose increases until 18 years of age. The upper nose height is found to increase 3 times more than the lower nose height, thereby maintaining a ratio of upper nose height to lower nose height of 3 : 1.
The skeletal facial convexity decreases in both sexes, while the soft tissue facial convexity, excluding the nose, is almost unchanged. The total facial convexity, including the nose, increases during the whole period. The result is that even if the skeletal angle indicates a straightening of the face, and the soft tissue angle shows no alterations, the profile, including the nose, shows a definite increase of the convexity. Thus, it seems that the growth of the nose is responsible for most of the profile changes [
On the other hand, in an individual with inherently small nose, it may be desirable to institute procedures which will cause the lips to retract. Retraction of the lips and continued facial growth may dramatically improve facial appearance.
Both upper and lower lips grow more than the skeletal lower face in children. In both absolute and proportional terms, the lower lip grows more than the upper lip [
The upper lip shows rapid increase in length from age 1 to 3 yrs. The rate of growth then reduces from age 3 to 6 yrs when again an upswing occurs till the age of 15 yrs. The growth curve for the upper lip is similar to the growth curve for the general body growth curve.
Most children with lip incompetence at age 6 experience self-correction by the age of 16. Lip competence is important in terms of not only esthetics but also stability of overjet correction. In this age group 6–8, it looks as though the incompetency is due to short lips whereas it is just incomplete soft tissue growth [
Genecov et al. [
In Subtelny’s study [
Mamandras [
The differential in the two sexes with respect to lip thickness implies that the treatment result of extraction therapy of the facial profile will be more noticeable in female than male patients.
Because female lips do not thicken with age, any extraction plan for females with straight to convex profiles should be cautiously considered. Lip fullness in relation to the nose which will continue to grow should also be noted [
In spite of progressive increase in length, both lips show a fairly constant vertical relationship to their respective alveolar processes. After the full eruption of the central incisors, there is little increase in the vertical distance between the crest of the alveolar process and the vermillion border of the lip. The lips also maintain an equally constant relationship to the incisal edges of the anterior teeth.
This is of great clinical importance because surgical overintrusion of maxilla results in an esthetically disastrous aging of the patient’s face. The male profile generally was shown to straighten with age with a concomitant retrusion of the lips, whereas the female profile did not straighten nor were the lips retruded [
The A-P posture of the lips is also found to be closely related to their supporting hard tissue structures, that is, the teeth and alveolar processes. The maxillary-mandibular dentitions progressively become more retruded relative to its supporting skeletal bone and to the facial plane of the skeletal profile.
Genecov et al.’s study [
In Nanda’s study [
Till 7 years the size of the mandibular corpus was the same for both sexes and the curves progressed parallel to each other till the age of 15 when the male sample had larger increases than the female. Increased chin projection seen in the males was due to the mandibular growth than the increase in soft tissue chin thickness.
Wisth [
An old adage is that children with a large symphysis would grow up to have an even larger one. However, when there is little symphysial prominence at the chin, the soft tissue chin can make up the deficiency [
The soft tissue structures overlying other skeletal landmarks do not show the same pattern of change as that observed for the bony profile. The average hard tissue profile definitely tends to become straighter with age whereas the analogous soft tissue profile tends to remain comparatively stable in its convexity.
Bishara et al. [
The upper and lower lips became significantly more retruded in relation to the esthetic line between 15 and 25 years of age in both males and females and similar trends continued between 25 and 45 years of age.
Torlakovic and Faerøvig [
Significant changes occurred in the soft tissue facial profile from the second to fourth decades. Aging of the male facial profile began 10 years later than for females; however, when the changes did occur, they were of greater magnitude. The upper facial profile was displaced in the anterior direction and the whole profile was displaced inferiorly for both sexes.
Bishara et al. [
Formby et al. [
With decrease in lip prominence and lowering of the nasal tip, nasolabial angle becomes more acute. As nasal tip descends and rotates, the lip descends with it in what is termed as a clockwise rotation of the nasolabial complex.
The nasolabial angle decreases slightly from 7 to 18 years in both sexes. The mean at 7 years was 107.8 ± 9.4 degrees for males and 114.7 ± 9.5 degrees for the females. At 18 years, the mean was slightly reduced to 105.8 ± 9.0 and 110.7 ± 10.9 degrees [
The mentolabial angle decreases slightly from 7 to 18 years in both sexes. The mean at 7 years was 125.3 ± 8.4 degrees for males and 136.1 ± 11.6 degrees for the females. At 18 years, the mean was reduced to 125.1 ± 12.9 and 127.1 ± 12.9 degrees [
It would be reasonable to assume that individuals would appear less protrusive as they age, due to a number of factors. The maxillary incisors are continually uprighting during adulthood and with the continued growth of the nose, repositioning of the lips, and the vertical increases, one could easily envision that the adult would appear less protrusive over time.
The mandible increases in size in both males and females, but in the male the occlusal plane tends to flatten and the gonial angle becomes more acute. The net effect is a tendency for a continued counterclockwise rotation of the mandible. In the female, more vertical change is evident and the mandible appears to be rotating clockwise [
The possibility that continued growth differences in males and females might suggest a greater possibility of relapse of female Class II cases than male Class II cases and of male Class III cases than female Class III cases. Conversely, male Class II and female Class III corrections might be enhanced [
As a person ages, the smile gets narrower vertically and wider transversely. The dynamic measures indicate that the muscles’ ability to create a smile decreases with increasing age.
A study by Desai et al. [
van der Geld et al. [
The significant increasing lip coverage of the maxillary teeth indicates that the effects of age should be included in orthodontic treatment planning.
Orthodontic treatment that diminishes lower facial height, reduces lip projection, decreases maxillary incisor display, or deepens the lateral nasal grooves should be avoided if possible because they hasten facial aging characteristics [
As a person ages, lower part of the face appears to lengthen, the interlabial line descends, and the number of vertical fibers in the upper lip reduces. The philtral columns become less prominent and the vermillion becomes a straight line. Jowling and increased nasolabial folds are seen. The M and W shapes of the lips may become straight and the commissures droop giving the look of a frown [
Crow’s feet at lateral corners of the eyes, horizontal lines on the forehead, vertical corrugations overlying the glabella, vertical furrows along the upper lip, horizontal crease above the chin, and a “turkey gobbler” bag of skin sagging down the skin below the chin can also be seen.
As general loss of body weight occurs, resorption of subcutaneous adipose tissue results in surplus of skin leading to sagging, wrinkling, and creasing. The distribution of collagenous matrix changes, fibres increase in massiveness, and whole skin decreases in resilience. The fibroblasts decline in number and cellular activities. Thus, there is a decrease of hydrophilic protein mucopolysaccharides leading to shrunken facial volume. There is darkening of skin below eyes because of more visible venous plexus in the thinned suborbital hypodermis. The suborbital integument also begins to sag to form bags [
Orthodontic tooth movement as a result of bone modeling and remodeling also depends greatly on age-related changes of the skeleton. Cortical bone becomes denser while the spongeous bone reduces with age and the structure changes from that of a honeycomb to a network [
Child face is not a miniature form of adult face. As growth process takes place, the changes in the hard and soft tissues of the face bring about a significant change in structure and profile of the face.
Knowledge about the age changes of jaws and soft tissue profile will help the dentists to aid in decision making to arrive at a comprehensive treatment plan and achieve better treatment efficiency.
The authors declare that there is no conflict of interests regarding the publication of this paper.