Later Stages Dr Majid Heidarpour

Adolescence 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 Adolescence Role of brain Releasing factors  Pituitary portal system  pituitary gonadotropins  Sex hormones

Initiation 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 Puberty Puberty 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 Puberty MALE: 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.

Adrenarche dehydroepiandrosterone, [DHEA]

Growth of the Nasomaxillary Complex

Growth of the Mandible

Timing of Growth Width  Length  Height

Rotation of Jaws

Internal Rotation

Superimposition

Superimposition

Superimposition (short face)

Superimposition (long face)

Changes in Arch Length

Changes 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: Late 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 Adults

References  Contemporary Orthodontics, 4 th ed 2007:  Chapter 4.