Later Stages

Dr Majid Heidarpour

AdolescenceAdolescence

Physical changes affect the face and dentition:

1- The exchange from the mixed to the permanent dentition,

2- an acceleration in the overall rate of facial growth, and

3- differential growth of the jaws.

Initiation of AdolescenceInitiation of Adolescence

Role of brain

Releasing factorsPituitary portal systempituitary gonadotropins Sex hormones

Initiation of AdolescenceInitiation of Adolescence

Neural growth is unaffected

by the events of adolescence, since it is essentially complete by age 6

The changes in the growth curves for the jaws, general body, lymphoid and genital tissues, however, can be considered the result of the hormonal changes that accompany sexual maturation

Timing of PubertyTiming of PubertyPuberty and the adolescent growth spurt occur on the average nearly 2 years earlier in girls than in boys

FEMALE:

Stage I : Physical growth spurt, appearance of breast buds and pubic hair.

Stage II: noticeable breast development, Pubic hair is darker and more widespread, axillary hair.

Stage III: onset of menstruation, noticeable broadening of the hips more adult fat distribution, development of the breasts

Timing of PubertyTiming of PubertyMALE:

Stage I: "fat spurt“ physically, Scrotum size and pigmentation.

Stage II: spurt in height, decrease in subcutaneous fat, pubic hair, growth of the penis.

Stage III: peak velocity in gain in height, axillary hair appears and facial hair appears on the upper lip only. A spurt in muscle growth, a continued decrease in subcutaneous fat and an obviously harder and more angular body form, pubic hair distribution.

Stage IV : Spurt of growth in height ends, facial hair on the chin, adult distribution and color of pubic and axillary hair, and a further increase in muscular strength.

AdrenarcheAdrenarche

dehydroepiandrosterone, [DHEA]

Growth of the Growth of the Nasomaxillary ComplexNasomaxillary Complex

Growth of the MandibleGrowth of the Mandible

Timing of GrowthTiming of Growth

Width Length Height

Rotation of JawsRotation of Jaws

Rotation of JawsRotation of Jaws

Internal RotationInternal Rotation

SuperimpositionSuperimposition

SuperimpositionSuperimposition

Superimposition (short face)Superimposition (short face)

Superimposition(short face)Superimposition(short face)

Superimposition (long face)Superimposition (long face)

Changes in Arch LengthChanges in Arch Length

Changes in Facial Soft TissuesChanges in Facial Soft Tissues

Continue with aging, much larger in magnitude than changes in the hard tissues.

Decrease in exposure of the upper incisors, and an increase in exposure of the lower incisors

Changes in Occlusion:Changes in Occlusion:Late CrowdingLate Crowding

Three major theories to account for late crowding:

1.Lack of "normal attrition" in the modern diet.

2.Pressure from third molars.

3. Late mandibular growth.

Facial Growth in AdultsFacial Growth in Adults

ReferencesReferences

Contemporary Orthodontics, 4th ed 2007: Chapter 4.