The document summarizes research on post-adolescent facial growth. It finds that: - Facial growth, including increases in dimensions of bones and soft tissues, continues throughout adulthood, though at a slower pace than during adolescence. - Males experience more prominent vertical changes while females show more horizontal changes. Chin position moves forward in both sexes but more so in males. - Dental changes also occur in adulthood, such as uprighting of teeth and slight increases in overbite, to compensate for facial growth and maintain occlusion. - Soft tissues like lips and nose continue growing and changing position into adulthood.

1. Post-adolescence Growth
8.1 Behrents RG (1985, 1989)219,220
Behrents studied post-adolescence growth by obtaining data from the Bolton Growth
Studies. It was a longitudinal study on subjects between 17-83 years old. He
investigated 163 cases (113 from untreated original, 40 years later) with 524 lateral
cephalograms (this is possible because the magnification in the x-rays was known
precisely).
Behrents found that facial growth continued throughout adult life. All of the facial
dimensions had increased but size and shape of the craniofacial complex altered with
time. Vertical changes in adult life were more prominent than A-P changes, width
changes were least  continuation of the patterns seen during maturation. Change in
magnitude per year is small but overall is quite significant. A 2-10% increase was the
rule: the bones of the cranial base, altering least, the facial bones a moderate amount,
frontal sinus more and soft tissue most. Females had an apparent deceleration of
growth in late teens follow by a resumption of growth in the 20s (child bearing age).
Vertical change was more characteristic of female.
Rotation of both jaws continued into adult life, coinciding with the vertical changes
and eruption of teeth. Male showed a net rotation of the jaws in a forward direction,
slightly decreasing the MPA. Females had a tendency towards backward rotation
with increase in MPA. Chin continues to be displaced in an anterior direction in all
ages more so in male. Tendency for the Female mandible to appear more retruded
with age even though the chin is coming forward. Compensatory changes were noted
in the dentition so that occlusal relationships were largely maintained.
Figure 1 Superimposition: untreated male and female. Dashed lines indicate the initial tracing
Little changes were detected in the region of pterygomaxillary fissure. Palatal
structures continue to relocates posteriorly and inferiorly (inferior change is greater in
males). Anterior palate moves inferior and anteriorly. Nasal region continues to
develop anteriorly so the position of the nasion and the tip of the nasal bone relocated
anteriorly. Female has the tendency for the tip of the nasal bone to elevate. Orbit
cavity increased in size in all direction.

2. Figure 2 Maxillary positional change and maxillary dimensional change based on palatal
superimposition
Chin is displaced anteriorly but much greater extent in male. Mandibular forward
rotation in males and backward in females were detected. Gonion move anterior and
inferiorly in males, posterior and inferiorly in females. Anterior border of the ramus
continues to relocate posteriorly with time. Posterior border of the ramus moves
anteriorly in males and remain stationary in females. Female’s chin moves forward,
the mandible is in effect rotating backward increasing the anterior vertical dimension
of the face with no relative movement of the chin.
Figure 3 Mandibular dimension changes and positional changes
Maxillary anterior teeth become more vertically upright but the lower anterior teeth
appear quite stable in their orientation with the tendency for proclination only in
females. Posterior teeth change their inclination in response to the altered positive of
the mandible. Axis of the molars shows a significant uprighting in Males and a
tendency for being more distally inclined in Females. Overbite increase with age but
compensated by attrition in most cases. Occlusal plane showed a decrease in
angulation in males and stable in females. Occlusal plane changes toward a flatter
plane. Continued increase in alveolar height with time in both arches

3. Figure 4 The direction of dental and mandibular plane movements and the resultant dental changes
Figure 5 Male occlusal plane changes
Soft tissue over nasal region, midface and the chin all move anteriorly. Nose grows a
great deal in size, become broader and the tip becomes more angular and downturned,
increase size of dorsal hump especially females. The height of the upper lip follows a
similar course and lengthens to the same extent that the nose grows. Lips increase in
length though they also flatten leading to more retruded position with time.
Mamandras (1988) showed that maximal lip thickness is reached in female by age of
14 and in male at age 16 and beyond this time there is a gradual thinning of these
tissues. Together with the growth of the nose and the anterior movement of the chin,
the teeth appear less prominent, lip area flattened and lips located more inferiorly
almost completely covering the upper incisors. Overall, there is a straightening and
elongation of profile
Figure 6 Soft tissue outlines for composite males and females

4. The clivis angle of the cranial base decreases in Class II and increases in Class III
individuals. Condyle tends to be more distant from sella in Class IIs and the reverse
for Class IIIs. Class II females may be prone to relapse after treatment than class II
males. Class III males would be prone to relapse than treated Class III females. Class
II correction in males depended more on an apical base change (growth) whereas in
female depended more on mesial movement of the lower molar along with a small
apical base change. (i.e. growth of male accomplishes the correction whereas females,
tooth movement is necessary). Correction of Class III is difficult in male and relapse
is likely. Because of the clockwise rotation of mandibles in females, treatment would
be aided by growth and relapse would tend to favour the maintenance of correction
Figure 7 Class II Treatment changes for male and females
8.2 Forsberg (1979)221
Growth changes in adult face were recorded form 24-34 years of age. There were 25
males and 24 females in the study with lateral cephalogram taken initially and 10
years after. 27 skeletal and 6 soft tissue variables were used and Frankfurt horizontal
is the reference base.
The significant changes in the vertical direction included an increased lower facial
height (ANS-Gn) of 0.39mm in female and 0.66mm in male. The angle SN:MP
increased in both sex but no changes in gonial angle was evident. The increased in
SN:MP was due to posterior rotation of mandible. The decreased in the incisor:SN
are necessary to maintain normal contact relationship between the teeth. There was a
continue forward movement of the apex of the nose and retrusion of both lips. A
posterior movement of soft tissue pogonion is also detected in females.
8.3 Sarnas & Solow (1980)222
Sarnas and Solow reviewed a sample of 50 Swedish females and 101 Swedish male
dental students using cephalometry. Examinations were carried out at the age of 21
years and 26 years old.
They found that:
 N point moved downward and forward 0.33mm
 S point moved downward and backward 0.33mm
 Total AFH ↑1.5mm with the LFH ↑ being larger
 Upper and lower dentoalveolar heights ↑0.5mm
 No change in upper and lower incisal angulations or interincisal angle
 Vertical OB ↑0.5mm

5.  Length of nose ↑0.75-1 mm in both sexes
 Height of the upper lip showed an increase of 0.5mm in both male and females
 Males lip thickness is reduced
 Tip of the nose was displaced forwards and downwards in relation to the ACB in
both sex
8.4 Bondevik (1995)223
Bondevik (1995) carried out a longitudinal examination of a large group of males and
females from beginning of 3rd to 4th decade. Cephalograms of all 3rd year Norwegian
dental students from 1972to 1983 (22years 3 months). 74 females and 90 males were
followed up 10years 9 months after. These subjects had no previous orthodontic
treatment.
Results showed that SN increased linearly in 36.5% females. The length of the
mandible increased in both sexes. PNS-ANS increased in 39.3% female and 42.2%
males. Vertically, the total face height has increased mainly in the lower facial height.
Anterior facial height increased more than posterior facial height in females and
opposite for males. The mandibular prognathism decreased in females. SN:MP
increased more than 10 in females and no change in males. There was no change in
the occlusal plane. Upper incisors and lower incisors were retroclined in both
genders. Thickness of lower lip and chin increased in males. The inferior part of the
upper lip become thinner and superior part become thinner only in females. There are
no change in the nose depth.
8.5 Nanda & Gosh (1995)224
Nanda and Gosh examined 17 males and 23 females from the Child Research Council
(Denver). The age ranged from 7-18 years and 6 or more x-rays were taken. They
discovered that the vertical dimension of the nose increased until 18 years. 80% of
the upper nose height is completed for both sexes at age of 7 years. Lower nose
height at age 7 is 90% complete in females and 67% in males. Males show a larger
increment of growth of the lower nose at 17 years. The nose projection is 70%
completed at age 7 in females and 63% in males. There is a significant increased at
age 17 years in males. Skeletal base to the nose measurement is completed by 17
years. Average upper and lower lip length in males is twice the females. 6.9mm for
males and 2.7mm for females. Short lip at age 7 will continue to have a short lip even
at age 18 years. Point A & B increased more than at the vermilion borders. The
lower lip thickness at vermilion border increased very little for females. Lips of
males increased 7mm in length and therefore can accommodate more protrusion of
incisors than the lips of females.
Adult Dentition
Arch length decrease form 14-18 years minimal intercanine decreases.227 Arch length
will continue to decrease at a declining rate after the age of 15 years (male and
female). This may contribute to relapse of incisor crowding.228 Permanent teeth
move and wear, resulting in shortening of the dental arches. Vego (1962) found that
there is greater (0.8mm) arch perimeter loss in cases with 8s and more crowding
develops in presence of 8s.229 All subjects (with or without 8s) had arch perimeter
loss. Sinclar & Little (1983, 1985) investigated the maturation of untreated normal

6. occlusions and found a decrease in the arch length and intercanine width.230,231 The
intermolar width is relatively stable. This is concurrent with the study by Carter &
McNamara (1998) that showed a decrease in arch width, length and perimeter
throughout adulthood.232 The mean decrement in any one dimension was less than
3mm. Mandibular incisor irregularity increased but not in all subjects regardless of
orthodontic treatment. The maxillary intermolar width, overbite, overjet and curve of
Spee are stable during adulthood
Post-eruptive movement
Teeth continue to move in three planes of space after their full eruption at an
approximate rate of 0.4mm per annum. There is many reasons for post eruptive
movement including compensation for occlusal and proximal wear as well as
accommodation for growth. The latter occurs to accommodate the final growth of the
jaws and usually complete by the late teens. Observing the effects of an ankylosed
tooth best sees the amount of growth occurs after eruption.