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Growth of The Soft TissuesGrowth of The Soft TissuesPostnatal Growth

Postnatal growth is defined as the first 20 years of growth after birth

krogman 1972

The study of growth in growing children is for two reasons :

-For health and nutrition assessmentof children living in a nationof children living in a nation.

-For comparison of a growing child with a large sample of other children

in the same population

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Soft Tissue Growth

1. Prenatal growth• I. Nasal growth• Ii. Lip growth

• 2 Postnatal growth

II. Soft Tissue and Hard Tissue.III. Soft tissue and cephalometricIV. Soft tissue and mal-occlusionV. Soft tissue and esthetics• 2. Postnatal growth

• I. Nasal growth• II Lip growth• Lip length• Lip thickness

III. Chin growth

The most important goals of orthodontic treatment are

harmonious facial esthetics, ti l f ti l l i doptimal functional occlusion and

stability

The importance of the oral musculature in orthodonticpractice is that it influences significantly the form of thed t l h i th t th li i iti f ilib i

SOFT TISSUE GROWTH

dental arches since the teeth lie in a position of equilibriumbetween the lingual and bucco-labial musculature.Therefore they are important factors in the aetiology ofmalocclusion, and greatly affect the stability of the resultafter orthodontic treatment.

Soft Tissue and Cephalometric

The soft tissue analysis is basically a a graphic record of a visual

observations made in the clinical examination of the patient.

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The facial musculature is well developed at birth,considerably in advance of the limbs, because of the needfor the baby to suckle and maintain the airway

SOFT TISSUE GROWTH

for the baby to suckle and maintain the airway.Other function soon develop: mastication as teeth erupt,facial expressions, a mature swallowing pattern (asopposed to suckling) and speech.

The lips, tongue, and necks guide the erupting teethtowards each other to achieve a functional occlusion.This serves as a compensatory mechanism for adiscrepancy in the skeletal pattern; for example, in aClass III subject the lower incisors may becomeretroclined and the upper incisors proclined to obtain

SOFT TISSUE GROWTH

retroclined and the upper incisors proclined to obtainincisor contact. Some times this compensatorymechanism fails, either because the skeletal problem istoo severe or the soft tissue behavior is abnormal.

An example of this is where lower lip function worsens aClass II division 1 malocclusion by acting behind theupper incisors rather than anteriorly to them.

SOFT TISSUE GROWTH

The lips lengthen as they mature in late stage of growth,tending to become more competent.

Muscles growth must be coordinated with the growth ofthe associated bones, with the muscles lengthening as theirbone attachments separate.

Neuro muscular activity regulate the position of the jaws

SOFT TISSUE GROWTH

Neuro-muscular activity regulate the position of the jaws,and it has been suggested that the whole process of facialskeletal growth is determined by the soft tissues whichsurround the bones

Summary Slide

• SOFT TISSUE GROWTH

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Growth in all living things implies that “changes”occurs as a function of “time”. The term “growthchanges” refers to any modification in the physicalsize shape or position of a structure

SOFT TISSUE GROWTH

size, shape, or position of a structure.

The term “development” will be reserved todescribe an increase in the complexity of afunction.Facial development is a continuous process

SOFT TISSUE GROWTH

Facial development is a continuous processspanning the pre and post natal periods.

B) Nasal growth

The face at the fifth week is about 1½ mm wide. Atthis time, the oral pit is bounded above by the frontalarea and below by the mandibular arch, whichappears shovel shaped.appears shovel shaped.

Nasal growthAt the sixth week, two small, oval, raised areas appearjust above the lateral aspects of the future mouth. In thenext 48 hours, the centers of these raised areas becomedepressions as the tissues around them continue to growanteriorly. The depressions deepen in to pits that willbecome the future nostrils and the masses surroundingthem will become the bridge and the sides of the externalthem will become the bridge and the sides of the externalnose.

Nasal growthThe tissue between the nasal pits is termed themedial nasal process and those lateral to the pits arecalled the lateral nasal processes .

Nasal growthThe distance between these two nasal pits dosenot increase during this important period ofdevelopment, although the pits themselvesincrease in both height and length. The twoepithelial covered processes together formepithelial-covered processes together formalamina termed as the (nasal fin).

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Lip growthat 6½ weeks, the facial proportions appear to havechanged greatly, due to an increase in dimensionlaterally to the pits.there has been in this short span of time anexpansion of anterior region of the brain causing thelateral maxillary regions to move the front of thelateral maxillary regions to move the front of theface. Thus, the eyes adjacent cheek tissues arerotated 90 degrees from the sides to the front of theface because of this differential growth.

Nasal growthAs soon as contact and adhesion of twoepithelial sheet occurs, they become fusedinto a single sheet and then degeneration ofthis sheet occurs, resulting in connectivetissue penetration through sheettissue penetration through sheet.

Nasal growthThis area of penetration expands rapidly and thenasal fin is eliminated except at its anterior andposterior limits. At the posterior limits of theepithelial fin, the same two epithelial sheets splitapart reducing and opening between the nasal pitsapart, reducing and opening between the nasal pitsand the roof of the oral cavity.

Nasal growth

This posterior opening of the nasal pit is termed theinternal nares and is the posterior limit of theprimary palate. Later, the nasal cavities enlargeposteriorly to form a space overlying the entire oralcavity. The oral and nasal cavities are then separatedby the secondary palatal shelves which close theanterior nasal opening, causing the resulting nasalcavity

2) Lip growthLip development is a three-stageprocess, the the first being contact of thetwo epithelial sheets covering thedj t th d f i fadjacent processes, the second, fusion of

the epithelium into a single sheet and,finally, a penetration of this sheet byconnective tissue of the lip growingthrough it.

Lip growthThe medial nasal area now makes up only therelatively small medial nasal tissue interposesbetween the maxillary wedges at this stage and willbecome the site of the future philtrum of the upperlip.Early in the seventh week, the face appearsrecognizably human as a result of the frontal locationof the eyes, differentiation of the nose andenlargement of the mandible. At the seventh week,the furrows separating the mandibular, maxillary andnasal areas are less marked

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B) Post natal growthThe human face has already a achieved about 75%of its adult size by the age of two yearsapproximately 85% by the age of 970. The differentcomponents of the soft tissue profile have differing

SOFT TISSUE GROWTH

p p grates and timing of growth12, 106.

1) Nasal growth

Studies suggested that nasal growth proceedsat a relatively constant into adulthood and thatthe nose increases in relative prominence asmaturity approaches25 28 77 86maturity approaches25, 28, 77, 86 .

The overall contours of the nose, and inparticular, the naso-labial angle, arenot likely to change by more than 3to 4 degrees as a child maturesg(Sorrell and Franks).

2) Lip growthPostnatally, a baby’s mouth at rest is closed. Thejaws are relatively little developed, the alveolarprocesses are not yet built up, the tongue liespartly between the arches of the jaws, and thereis ample lip tissue to maintain mouth closure. Inthe period from birth to the first transitionalthe period from birth to the first transitionalperiod, normal mouth closure is maintained.

Lip growthThe rapid growth of the jaws and development ofthe teeth seldom give rise to a situation where theavailable tissue is adequate to provide good lip seal.This problem usually arises only after maxillarypermanent incisors have been in the mouth sometime and the development of the lip is relativelytime and the development of the lip is relativelybehind that of the dentition40.

a) Lip lengthLip position is affected by the placement and inclinationof the maxillary and mandibular incisors and hence isresponsive to orthodontic treatment.

The average increase in upper and lower lip length inmales is more than two times that of females.

In age from 7 to 18 years, the total increase in upper andlower lip length in the males is 6.9 mm, in the female, itis only 2.65 mm.

Those with a short upper lip at 7 years will continue tohave a short upper lip even at age 18 years. Nanda, et al:1990

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Lip lengthThe relative growth increment in upper andlower lip length is greater in the long facethan it is in the short face subjects at age 7years. (Nanda and Ghosh)

The longer upper and lower lips in the long-face groups could have been compensatorymechanism for the individuals to obtain a lipseal.

Because shorter facial patterns have a decreasedvertical dimension, the length of the upper andlower lips would not have to be as long for a seal

b d d

Lip length

to be produced.Smaller lip length in short face subjects could bedue to lip closure, However, it should lead to agreater gathering of lip tissue and an enhancedthickness.

Lip thickness

b) Lip thickness.The tendency for females to havesmaller soft tissue dimensions thanmales was clearly demonstrated in theyrelative thickness of the soft tissue ofthe lip and chin. Females demonstratedthinner lips at age 7 and grow similaramount to males up to age 12.

Lip thickness.The final lip thickness in females were oftenless by 2 mm or more at age 17 due toalmost no increase occurring in femalesfrom age 12 to 17 years. Thus, a clinicianretracting upper incisors in a 12 year oldretracting upper incisors in a 12 year oldfemale might expect little compensatory lipgrowth, while in male as less detrimentalfacial effect might be expected if the normaltwo mm increase in upper lip thicknessoccurred from 12 to age 17 years44.

Lip thickness at point A and B increased morethan at the vermilion borders. The increase inlower lip thickness at vermilion border wasvery small for the females. These changes leadto thicker, longer lips for the males77 .While the changes in the thickness of upper lipat liberal superius did not show any distinctpattern between the long face and short facesubjects, the relative growth in the lower lipthickness at liberal inferius was greater in theshort face subjects76 .

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Lip thicknessAfter adulthood is reached, changes continuein the morphology of the craniofacial skeleton,position of the teeth, and soft tissues. Theprofile becomes straighter, the upper lipp g , pp pbecomes longer and thinner, and theprominence of the lower lips decreases withage; is smiling and speaking the maxillaryincisors show less, the mandibular incisorsshow more.

Lip thicknessbecause a lip growth only begins to catch upwith vertical growth of the lower part of theface after completion of transition, it is thepermanent incisors that dominate the facebefore and during adolescence. Only infollowing years dose the dentition retreat in tothe face, due on the one hand to the continuedforward growth of the jaws and the associateduprighting of the incisors, and on the otherhand, the relatively greater increse in a liplength40 Frans and v. lindin 1990 .

Chin growthGenecov and his co-worker reported in theirstudy that the soft tissue chin thickness infemales at 7 to 9 years was greater than inmales (being 11.7 and 10.8 mm respectively)but only demonstrated a 1.6 mm increase up toage 17, while the males demonstrated 2.4 mmof increase any tissue thickness over thisperiod.

Chin growth (cont.)

In women, the reduction in thickness at thesoft tissue chin may have been caused by theincrease in the anterior face height and smallincrease in the anterior face height and smallincrease the mandibular plane angle causingslight stretching of the soft tissue over the chin( summary of profile changes in adult lifefollows).

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SOFT TISSUE AND HARD TISSUE

The early studies suggested that therewas a general consinsous of the patternof skeletal growth assuming that theof skeletal growth assuming that thedevelopment of the soft tissue profilewas coincident with the underlying hardtissues Brodie1953 Fishman1969 Reidel 1957

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However a considerable body of evidence nowexists which suggested that different componentsof the soft tissue profile have differing rates andtiming of growth and that all parts of the softtissue profile do not grow in direct proportion totheir skeletal bases Bishara et al 1984 Subtelny 1959 Burstonetheir skeletal bases Bishara et al 1984 Subtelny 1959 Burstone

However Burstone suggested that a closerelationship of the soft tissue profile to theunderlying skeletal pattern might not existbecause of the variation in the thickness of thesoft tissue covering the skeletal face.

Bowker and Meredith1959, in their longitudinalstudy, showed changes in soft tissue profilebetween 5 and 14 years with growth; but didnot relate this to the underlying skeletal pattern.

Subtelny 1959, in a longitudinal study of soft tissueprofile, measured vertical and horizontal

l i hi d f d h ll f hrelationship and found that not all parts of thesoft tissue profile directly follow theunderlying skeletal structures. For example, thesoft tissue over bony A tended to increase inthickness with age.

Tulley and Campbell 1970, do not feel that SoftTissue A and B points accurately reflect theposition of skeletal points A and B, theyrecommend palpation of these areas. Wisth 1972,also observed that changes in soft tissue profilefollowed changes in skeletal profile but noticedvariations over points A and B.

Mauchamp and Sassouni 1973, studied the effectof aging on the skeletal and soft tissue profiles.They found the soft tissue changes to be similarto the underlying skeletal changes. Anotherstudy done by Barnett , which supported thefindings of Reidel, Subtenly and Mauchampand Sassouni that the soft tissue profile gives aand Sassouni that the soft tissue profile gives agood indication of underlying skeletaldiscrepancies. Indeed their statistical testsindicate that the difference in maxillary andmandibular prognathism could be estimated asreliably from the soft tissue profile as fromangle ANB.

They also found that the position of the bony Bpoints is very accurately reflected by theoverlying soft tissue contour while the bony Apoint seems to be more variable. This may bebecause it is a difficult landmark to locate onlateral skull radiographs. Nevertheless, itsposition is reliably reflected in the soft tissueprofile and there is apparently no necessity topalpate the maxilla in this region.

It was interesting that the upper lip over Apoint is thicker than the lower lip over B pointand the relationship remains unchanged withgrowth. Another interesting result showed thatlower lip thickness was significantly correctedwith chin thickness for the both group(ten years group and over 16 years group)(ten years group and over 16 years group).But the correlation coefficient for the over 16years old group was found to be less due tocontinued growth of the bony chin with age .

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