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Introduction
Every individual matures according to his or her own biological clock.
Different authors had reported different methods in an attempt to determine the best indicator of
maturity.
These include height weight; chronological age sexual maturation , Frontal sinus, biological age or
physiological age; Hand-wrist maturity Cervical vertebrae dental eruption; dental calcification stages,
and recently biomarkers.
Requirement of an ideal maturity indicator
- Should be safe and non invasive
- Require minimum radiation
- Should be accurate Stage of maturity
- should be well defined
- Easily identifiable Cost effective
- Require minimum armanterium
- Simple to conduct
- Valid overtime and across age group
1-Biological age or physiological age
The physiological age of a person is determined by the degree of maturation of the different tissue
systems.
Physiological age can be estimated by maturational status of somatic, sexual, skeletal, and dental
system.
Somatic maturity Annual growth increments in height or weight determines the somatic maturity.
Measurement of height represents general growth of the skeleton.
Average age of onset of stature growth for females and males of approximately 10 and 12 years,
respectively, with the peak coming later in both sexes .
Height, therefore, might represent a skeletal measure that can be used to predict the timing of the
facial growth spurt and needs further exploration.
Maturational development embodies the overall biologic progression through life.
In the growing years indicators of level of maturational development of the individual provide the best
means for evaluating the biologic age.
Maturational development can be accurately assessed with the help of all the indicators previously
described. However it must be kept in the mind that every child demonstrates a unique sequential
pattern of events. No child is same as the other.
The growth factor is a critical variable in orthodontic treatment .
The purpose of assessment of pubertal growth spurt is that there is growth of facial dimensions during
this period .
Skeletal indicators of maturation have been proved to be the most reliable .
A combination of skeletal and dental indicators tend to give a very accurate picture of each child’s
developmental status
Finally it must be kept in the mind that in orthodontic practice it may be more relevant to evaluate the
development of the patient in relation to his own growth potential in order to assess whether peak
velocity growth is imminent, present, or completed .
The choice of indicators to be used finally depends upon an orthodontist‘s preference .
2-Sexual maturation
Sexual maturation involves using secondary sex characteristics to predict the individual maturational
status.
Tanner had given separate sexual maturity ratings for boys and girls which consists of five stages of
sexual maturity with stage 1 being the least mature (preadolescent) and stage 5 being the most mature
(adult)
In boys, Tanner Sexual Maturity Ratings assesses pubic hair (amount, coarseness, color and location),
penile length and breadth, scrotal development and testicular size.
In girls, tanner sexual maturation rating assesses breast development (size and morphology) and pubic
hair (location, color, morphology, quantity).
In girls, tanner sexual maturation rating assesses breast development (size and morphology) and pubic
hair (location, color, morphology, quantity).
Prediction of sexual maturity requires a physical examination, and hence use of sexual maturity as
maturation marker is limited in the orthodontic set up.
Serial recording of voice change in boys can be used as a measurement of maturity but as mentioned
above it requires a serial recording, not practical in orthodontic clinics .
Menarche is an important predictor of maturation in females, Once menstruation begins, the growth
spurt is usually near completion.
N.B Skeletal maturation Certain bones in the body demonstrate an organized event of ossification.
Degree of ossification in these bones determines skeletal maturation. These changes can be seen
radiologically. The hand, foot, knee, elbow, shoulder, and hip, cervical vertebrae can be used to assess
skeletal age of an individual. Out of the above-mentioned bones, hand-wrist and cervical vertebrae
methods has been explored extensively as indicators of maturity
the majority of female orthodontic patients have passed the pubertal growth spurt when they
experience their menarche. Menarche usually follows the pubertal growth spurt by about 1 year
3-Assessment of physical maturation and somatomedin level during puberty
Since the pubertal period is initiated by gonadal secretions controlled by FSH AND LH.
So appearance of these hormones may serve as indicator to the onset of the adolescence .
(Odell W.D et al 1967) The role of growth hormone has been described as an indirect because of its
action through SULFATION factor.
Sulfation factor acts directly on the cartilege and has got long half life in the plasma which makes it
rational to look for changes in plasma level during puberty .
A pilot study was done on 27 Caucasian girls and there developmental status was classified as
prepubertal,circumpubertal and post pubertal by an qualified pediatrician .
An orthodontic assessment was made including clinical dental examination ,lat.ceph,wrist radiograph of
left hand and height and weight determination.blood samples were taken to determine the plasma
somatomedin levels .
The results showed that there was significant difference between the somatomedin levels in the plasma
of circumpubertal and postpubertal females.
however no significant difeerence was found the between the prepubertal and the circumpubertal
group.
In addition the skeletal age appeared to be better indicator of the physical maturity than the
chronological age
4-Serum PTHrP level as a biomarker in assessing skeletal maturation during
circumpubertal development
Mean serum PTHrP levels were significantly higher in the late pubertal stages than in the early pubertal
stages. Pearson correlation showed that serum PTHrP levels had a positive correlation with cervical
vertebral maturation stages from the prepubertal to the late pubertal stages, and a negative correlation
from the late pubertal to the postpubertal stages
5-Serum and urine insulin
Salmon and Daughaday were the first to discover IGF-I as a mediator of growth-hormone function,
which was termed the sulphation factor.
Several studies reported that its serum levels in children and adolescents followed a pattern that was
closely related to the pubertal growth curve .
Urine and serum insulin-like growth factor-1 (IGF-1) are regarded as promising biomarkers for growth
assessment.
They follow the pubertal growth curve without the subjectivity of radiographic markers.
The peaks in serum and urine IGF-1 were observed in stage 4 of the cervical vertebral maturation index.
A significant positive correlation was seen between serum and urine IGF-1.
Urine IGF-1 is a noninvasive surrogate for serum IGF-1
6-Massater muscles conduction velocity and direction of mandible Growth
Moss and Rankow reported that the function of the stomatognathic muscle affects the growing
cranioface and plays a role in its morphogenesis Masseter muscle conduction velocity and direction of
mandibular growth
Human skeletal muscle fibers are classified into 2 types—
-fast- twitch (F type or type 1) and slow twitch (S type or type 2)
— based on contractility and tissue images, and muscle function is characterized by the composition
ratio of these types of muscle fibers.
There is a strong correlation between the muscle conduction velocity (MCV) measured by using an
electromyogram and the muscle fiber composition .
Ogata et al reported that a long face, in which the lower facial height is long, has a lower conduction
velocity of the masseter muscle in maximum voluntary contraction and more type 1 fibers than a short
face .
therefore, by understanding the muscle fiber composition of the masseter muscle in childhood, it might
be possible to predict the direction of growth of the mandible or vertical craniofacial morphology with
non invasive methods .
7-Gingival crevicular fluid protein content and alkaline phosphatase activity in
relation to pubertal growth
Gingival crevicular fluid (GCF) is a potential source of biomarkers, with molecular constituents that
derive mainly from serum, and also from the interstitial fluids of periodontal tissues.
ALP is an enzyme that is necessary for bone mineralization, with its activity shown to be correlated with local tissue remodeling during orthodontic tooth movement and periodontal inflammation.
This study was proposed as a non invasive diagnostic aid for the determination of optimal treatment
timing in functional jaw orthopedics.
Both the volume and total protein content of the GCF have been used extensively to calculate the
concentrations of the different GCF constituents, for their normalization .
Total GCF protein content is not a reliable indicator of the different growth phases.
While confirming that total GCF ALP activity would be a reliable biologic indicator of skeletal
maturation.
GCF ALP activity is a promising diagnostic tool for identification of the growth phases in individual
subjects when expressed as the total, rather than the normalized .
8-SERUM DEHYDRO EPIANDROSTERONE SULPHATE AND SKELETAL
MATURATION
Puberty is a neuro endocrinal event with the pituitary and hypothalamus playing a major role in its
initation.
Both the pituitary and hypothalamus are together called gonadostat .
In puberty, gonadotropin releasing hormone is secreted from the hypothalamus, which stimulates the
pituitary to secrete gonadotropins (FSH, LH )
These gonadotropins stimulate the gonads to secrete the sex steroids testosterone and estrogen, which
inturn affects skeletal maturity in puberty.
For the gondaotropins to iniate its action, it requires stimulation from the adrenal gland.
Adrenal gland secretes steroids like dehydroepiandrosterone (DHEA) and its sulphated conjugate
dehydroepiandrosterone sulphate (DHEAS). Auches and Rainey 2004
They are present in circulation approximately 3 years prior to puberty .
This period is termed as adrenarche .
These steroids can stimulate growth and proliferation of epiphyseal cartilage and potentiate action of
growth hormone (GH).
DHEAS has been found to enhance bone deposition to increse bone mineral density, and to maintain
the cancellous and cortical bone mass by way of protective action in osteoblasts.
Serum levels of DHEAS are high in neonates, after which there is a decrease , then a rapid increase in
the serum levels from 7 years of age in females and 8 years of age in males, with a gradual increase
until it attains adult value .
9-Eruption of maxillary canine and skeletal maturity
Hagg and Taranger reported that all canines and premolars are usually erupted by the end of the
pubertal growth spurt .
This was confirmed with the hand wrist .
Erupting permanent canine in a 12 year 9 month old patient with CS3 stage .
In 56.6% of patients, the canine erupts in the dental arch at least 1 year before the pubertal growth
spurt .
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