Orthodontics Q & A

Describe the methods available for prediction of craniofacial skeletal maturation. To what extent these methods are reliable to use in clinical practice.


Growth and development of human is not uniform but has periods of acceleration and deceleration. The typical growth pattern of a child is characterized by a growth rate that decreased from birth with minimum mid growth spurt at approximately 6-8 years of age a pubertal minimum and pubertal growth spurt.(Brown 1970, Houston 1980)

During the pubertal growth spurt the velocity of growth is greater than at any time at which orthodontic treatment might be undertaken. If treatment techniques that depend on growth is undertaken during this period maximum benefits can be obtained. Therefore prediction of the pubertal growth spurt both in time and amount of active growth especially in the craniofacial complex would be useful to the orthodontist.

Many methods have been proposed in the past and had been investigated for their accuracy in clinical application.

Chronological age.

Chronological age cannot be used to identify stages of developmental progress through adolescence to adulthood ( Fishman 1979, Knckkels Acer et al 1999)

Although growth events usually proceeds in a fairly predictable sequence their timing is variable among individual children.

Therefore, developmental status is better assessed by physiologica parameters such as PHV in standing height , voice changes in boys menarchey in girls dental development and skeletal ossification.( Moore, Moyer et al 1990)


Craniofacial skeletal maturation.
Many studies have shown positive relationship between maximum facial growth and peak height velocity. They disagree regarding the sequence of the two events. Hunter 1966, Bergerson 1972, Grave 1973, Thompson and Popovish 1973 concluded that PHV and maximum facial growth are coincident.

In contrast Nanda 1955, Bambha 1961, baughan et al 1979 fishman 1982 have reported maximum pubertal growth lags behind by variable amounts of time. Silveira and Fishman 1992`have shown that during the adolescent growth spurt , rates and magnitudes are different in those who mature early and those who mature late and also mandible grew significantly more than the maxilla during the late stages of pubertal growth spurt.


Height and PHV.


Adolescent phase of growth varies fro different individuals ,
1. in the age f onset
2. the intensity,
3. duration of the spurt.
Maturation rates are influenced by diverse factors

1. genetic and racial factors.
2. climatic and seasonal conditions. Socioeconomic conditions
3. secular changes early maturation in different generations.


Timing of growth spurt varies slightly in different parts of the body. But in most facial dimensions it seems to occur about the same time as the stature. Nanda 1955, Bergersen 1972, bjork 1972.

On average pubertal growth spurt was reported to begin at an age of about 10 years. In girls, 12 years in boys in both PHV occurs 2 years after onset. Hagg and Taranger 1982. end of the spurt in girls 15 boys17 years. Mean duration of growth spurt 4.7in girls 4.in boys. Taranger and Hagg 1980.

PHV can be identified in serially plotted curves.

Many studies have shown a strong correlation between PHV and facial growth. Hagg and Taranger 1982, Therefore longitudinal records of height can be used for evaluation of facial growth rate during puberty.

Drawbacks.

These records are seldom available.
It may be difficult to locate the pubertal growth spurt before it passed as increase in growth rate is small.
Most of the time clinician must base his judgment on single reading.
Stature is not an indicator of maturity.

Thus additional information is necessary to estimate the maturation level of the individual.

Dental age.

Stages of dental maturation is determined by tooth formation. Bjork, Krebs 1964)

Facial growth and dental maturation has a very low correlation.
Nanda 1960 usedcompletion of permanent dentition, Lewis and Garn 1906 uses attainment of occlusal level of second molar. And showed correlation of 0.60

Many studies have shown low correlation.

Sexual development.

Hag and Taranger summerized their findings regarding menarche and PHV.

1. If menarche has occurred PHV has been attained and the growth rate is decelerating.
2. If menarche has not occurred, the growth rate may be decreasing but has certainly not reached the levl of the end of the pubertal growth spurt.

Hagg and Taranger 1980 examined the voice changes in boys and concluded.

1. if a boy has pre pubertal voice, it is most probable that PHV has not hyet been reached.
2. if the voice change has begun, the boy is in the pubertal growth spurt
3. if boy has male voice, he growth rate has begun to decelerate.
4. no boy will reach the end of the pubertal growth spurt without having a male voice.

Skeletal development

Skeletal maturation refers to the degree of development of ossification in bone. During growth every bone goes through a series of changes that can be seen radiographically.


Hand and wrist radiograph
The use of skeletal age has been shown to be more reliable and precise than chronological age in assessing the progress of an individual towards maturity. Moed, Byron et al 1962

The radiograph of hand and wrist has been the most frequently used because many centers are available in this area of the skeleton that undergo changes at different times and rate.
As may bones are in this area child receives little radiation. Roche, Chumlea et al 1988

Skeletal age can be evaluated by two methods.

1. comparing the radiograph of the patient with a seires of standard films representative of normal children at different age groups and assigning to the film in question the age of the standard which matches with it closely. Greulich and Pyle 1959
2. assigning a weighted score to the developmental stage of each of the 20 bones in the hand and wrist and the bone age is the total score for the radiograph Tanner and Whitehouse 1982

Atlas method.

Greulich and Pyle method consist of a series of standard plates obtained from white upper middle class boys collected from Brush foundation growth study. 1932- 1942. standards represents central tendencies. Which are modal level of maturity within chronological age groups. Radiograph is compared with the standard plates bone age given which more closely resemble.

Problems.

Assumption of evenly maturing skeleton,
Concept of skeletal age.
The way in which the bone age is assessed.
Time consuming approach.



The TW2 method.

It differs from Greulich method in two ways.
1.it uses bone specific approach
Results not expressed in skeletal age.


TW2 method assess the maturity of 20 bones. Radius,ulnar Carples metacarples nad phalanges of first third and fifth finger

Individual bone are matched to a series of written criteria describing 8or 9 standard stages A-h or I. each stage is defined by upto three criteria and results in a skeletal maturity score SMS

Three different SMS

20 B 20 bones.
Carpal bones CB
Radius ulnar and short bone RUS


Weaknesses

1. very minor criteria used to differentiate stages.
2. SMS may change by rate one bone younger or older.



SMI method

Fishman developed a system Fishman 1979

Six anatomical sites located on the thumb third finger fifth finger radius eleven discrete adolescent skeletal maturational indicators SMI’s covering entire period of adolescent development. Are found at these sites.

Four ossification stages.
1. ephiphyseal widening on selected phalanges.
2. the ossification of the adductor sesamoid of the thumb
3. capping of ephyses over their diaphyses
4. fusion of selected ephiphyses.

Ig adductor sesamoid of thumb is not visible early stage of maturation.
Late stages lf adolescent growth coincide with fusion of third finger SMI 8,9,10and fusion of radius SMI 11.Kopecky and Fishman shown best time for wear of cervical headgear s SMI 4-7 very high velocity growth period. Least desirable SMI 8-11.


Fells method

Published in 1988. by Roche and Chumlea et al 1988. it has 98 maturity maturity indicators.

Provide bone specific ages.not skeletal maturity

Ulnar sesamoid.

Highly correlated with PHV. And the start of the pubertal growth spurt.
Ossification begins in females 10-11.5 years.
Males 12-14.5b years. Range three females 4 and ½ for males.

PHV follows about one year appearance of adductor sesamoid.

Hagg and Taranger concluded that

If sesamoid is not ossified, PHV has not been reached.
If the sesamoid has just become visible, most children are in the acceleration period of the pubertal growth spurt.



Hand wrist radiaograph may presnt with a numerous problems

1. incorrect hand positioning may result in rotation and totally incorrect findings.
2. it may not be representative.
3. margin of error +/- 6 months in a clinical setting.



Cervical vertebrae


I 1972 Lamparsky clinically and statistically reliable in assessing skeletal age.

They are same in both sexes but in females it appear earlier.
Six different stages.second to sixth cervical vertebrae.

Haseel and Farman developed six categories using c2, 3 and 4 this had good correlation to hand wrist radiograph.
Even if the patient wears protective coller they are visible.CVM categorized further pre peak,peak and post peak. Baccettiand Franchi 2001 have used it for timing of RME.

First stage vertebrae is wedge shaped with superior vertebral border tapered posteror to anterior
With growth they become reactangular, square shaped and lastly rectangular with height greater than width
San Roman and Palma et al 2002. reported that parameter best able to estimate is concavity of the lower border of the vertebrae. They also reported that Hassel and Farman CVm method is good for both males and females. Lamparsky method only for females.

Bacceti, Franchi et al 2002. proposed a improved method of CVM.

Five stages of development recorded for C, 2, 3 and 4


Advantages.

The method has definite stages coinciding with the peak in mandibular growth
No additional exposure to X rays is required.
Recording is relatively easy.
Inter examiner errors is low.
Is useful in anticipating pubertal peak of mandibular growth.



When CVMs 1 is diagnosed for an individual patient clinician can wait for one year before starting treatment for mandibular deficiency.

CVMS !! represent ideal age to begin functional jaw orthodpedics. As peak of mandibular growth will occur within one year after this observation.




Three finger method.

Expose with the ceph.

Three fingers with the lateral ceph has advantages over cervical vertebrae.

. maturity indicators of cervical vertebrae undergo very subtle changes through time and are not easily visualized as three finger method.
Improper posture of the neck area may lead to error
Thyroid collar may not show cervical vertebrae.