growth prediction (amount, direction and spurt) with relevance to orthodontics by almuzian

Growth prediction (amount, spurt and direction)

Mohammed Almuzian, 2014, University of Glasgow


Adolescence is the transitional period between the juvenile stage and adulthood, during which secondary sexual characteristics appear, the adolescent growth spurt takes place, fertility is attained, and profound physiologic changes occur.

Methods of prediction of the onset of the pubertal growth spurt

How can we determine growth in a population?

Longitudinal studies – take a long time

Cross sectional studies – measure boys and girls at one time and all ages

Mixed longitudinal and cross sectional follow groups over time i.e. 3-4 years

Timing of PGS varies between individuals, on average 2 years earlier in girls than boys

Tanner & Davies 1985. Average timing of onset of PGS is 14 +/- 2(boys) & 12 +/- 2 (girls)

Tanner 1976. PGS lasts 3½ years in boys & 2 years in girls, with PHV occurring in the

middle. While profit 2000 mentioned that the estimated the PHV to be 13.5 +/- 0.9 yrs for

boys and 11.5 +/- 0.9 yrs for girls. He states that puberty lasts about 5years in boys compared

to 3.5 years in girls. Considerable variation occurs due to:

1) Genetic factors - early/late maturing families, ethnic and racial variation.

2) Environmental factors - seasonal factors (spring, summer)

3) Cultural factors - City children

4) Seasonal factors

5) Juvenile acceleration - Occurs mainly in girls and growth starts 1-2 years before puberty.

This growth can equal or exceed that of puberty.

Methods prediction of growth timing and variability

A. Methods prediction of growth variability

1. Growth chart to assess growth variability:

An individual who stood exactly at the midpoint of the normal

distribution would fall along the 50%line of the graph. One who


was larger than 90%of the population would plot above the 90%line; one who was

smaller than 90%of the population would plot below the 10%line.

These charts can be used in two ways to determine whether growth is normal or

abnormal.

First, the location of an individual relative to the group can be established. A general

guideline is that a child who falls outside the range of 97%of the population should

receive special attention.

Second and perhaps more importantly, growth charts can be used to follow a child

over time to evaluate whether there is an unexpected change in growth pattern.

When is further growth assessment required? If any of the following apply:

I. Height, Weight or BMI is a 0.4th centile

II. Height centile > 3 centile spaces below the mid-parental centile

III. Drop in height centile position of more than 2 centile spaces

IV. Any other concerns about the child’s growth.

A. UK-WHO growth charts

Based on (WHO) Child Growth Standards

Describe the optimal growth for

healthy, breastfed children.

Combine UK90 4-18 yrs and WHO

data 2-4yrs

Therefore covers ages 2 to 18

Technique:

Tadiometer

Shoes off

Heels, bottom back of head

Frankfort Plane Horizontal

Breathe in & then out

Measure to nearest mm


Plot on chart which could be:

B. Tanner – Whitehouse:

Plot height directly but it is now considered as old since 1960 and there

is a Secular trend for increasing height.

B. Methods prediction of growth timing

2. Physical changes

3. Chronological age: Poor predictor as considerable variation in timing of adolesence.

However, Perinetti 2014 showed that this method is not worse than CVM in predicting the

growth and it could be reliable.

4. Dental Age: Poorly correlated with growth.

5. Secondary sexual characteristic features:

Adolescence in girl can be divided into three stages, based on the extent of sexual development. The first stage, which occurs at about the beginning of the physical growth spurt, is the appearance of breast buds and early stages of the development of pubic hair.The peak velocity for physical growth occurs about 1 year after the initiation of stage I, and coincides with stage II of development of sexual characteristics. At this time, there is noticeable breast development. Pubic hair is darker and more widespread, and hair appears in the armpits (axillary hair). The third stage in girls occurs 1 to years after stage II and is marked by the onset of menstruation. By this time, the growth spurt is all but complete. At this stage, there is noticeable broadening of the hips with more adult fat distribution, and development of the breasts is complete.In boys, four stages in development can be correlated with the curve of general body growth at adolescence. The initial sign of sexual maturation in boys usually is the “fat spurt.” The maturing boy gains weight and becomes almost chubby, with a somewhat feminine fat distribution. At stage II, about 1 year after stage I, the spurt in height is just beginning. At this stage, there is a redistribution and relative decrease in subcutaneous fat, pubic hair begins to appear, and growth of the penis begins. The third stage occurs 8 to 12 months after stage II and coincides with the peak velocity in gain in height. At this time, axillary hair appears and facial hair appears on the upper lip only. Stage IV for boys, which occurs anywhere from 15 to 24 months after stage III, is difficult to pinpoint. At this time, the spurt of growth in height ends. There is facial hair on the chin and the upper lip, adult distribution and color of pubic and axillary hair, and a further increase in muscular strength

C. Height/Weight ratios and height

Itself is not highly correlated with facial growth (Tanner and Whitehouse 1976).


D. Peak Height Velocity (PHV)

It came from the data of de Montbeillard (1720-

1785)

Developed by Tanner & Whitehouse 1966 who rely

on the data of Harpenden Growth Study 1950s that

involve measurements of height on 49 boys and 41

girls.

It involves Ploting change in height on a chart and it

is more useful but with Secular trend less

Growth spurt on average begins 1 year before PHV (probably the best available method).

It shows three general phases in the growth curve:

• A rapid rate of growth at birth, which progressively decelerates until around 3 years of age;

• A slowly decelerating phase, which persists until the adolescent growth spurt in the early

teenage years and is interrupted by a brief juvenile growth spurt at around 6 to 8 years; and

• An adolescent growth spurt, which is followed by a progressive deceleration in growth

velocity until adulthood.

Sullivan 1983 method based on standard growth velocity charts (Tanner 1966), measuring

standing height at 4 monthly intervals from age 9, transparent template to estimate when

growth is about to accelerate. Method found to be acceptably accurate, but more accurate in

boys than girls

6. Cephalometric standared like Bolton norms

7. Hand Wrist Radiographs:

Ossifying Events - these are correlated fairly well with PHV but variation is too wide to be of

predictive value (Gruelich and Pyle, 1959). It is more retrospective technique for growth

prediction. Grave & Brown 1979 described skeletal indicators (such as ossification of the

ulnar sesamoid) to assess maturity. Gruelich & Pyle 1959 method involving comparison of

films to standard atlas to assess bone staging.


Houston 1979 - single ossification events not sufficiently accurate to be useful for prediction

- based on this, Isaacson & Thom 2001 BOS guideline do not recommend the use of the

method.

However, Flores-Mir 2004 systematic review concluded that hand-wrist films are useful for

assessment of skeletal maturity in carefully selected cases, using method of Gruelich & Pyle

rather than single ossification event.

However, additional radiation exposure, limited accuracy. Indications in routine clinical

orthodontics very limited.

8. CVM

Appearance of cervical vertebrae on lateral ceph to assess skeletal maturation (Franchi

2000). First proposed – Lamparski 1972

However, Hunter 2007 has shown poor correlation between skeletal age and peak mandibular

velocity (PmdV), and therefore CVM (or hand-wrist films) may not be a useful predictor of

growth of jaws.

Simplified method described by Baccetti 2002. Bacetti et al. 2005 used longitudinal data and

related it to annual change in Co-Gn

- 5 stages of development, based on morphology of C2, C3 and C4. PHV between CVM II

and CVM III. Advantage - no additional x-ray exposure. Method useful in anticipating the

growth spurt, and establishing whether PHV has occurred.

CVMS 1: The lower borders of C2, C3 and C4 are flat. The bodies of both C3 and C4 are

trapezoid in shape. The peak in mandibular growth (PMnG) will occur on average

2yrs after this stage

CVMS 2: C2 lower border is now concave. C2 and C3 are still trapezoid in shape. The

PMnG will occur on average 1yr after this stageMohammed Almuzian, 2014, University of Glasgow

CVMS 3: The lower border of C2 and C3 are concave. The bodies of C3 and C4 may

be either trapezoid or rectangular horizontal in shape. The PMnG will occur during this

stage

CVMS 4: C2, C3 and C4 lower borders are concave. Both C3 and C4 are rectangular -

horizontal in shape. PMnG has occurred within 1 or 2yrs before this stage

CVMS 5: At least one of the bodies of C3 and C4 is squared in shape. The PMnG has

ended at least 1yr before this stage

CVMS 6: At least on of the bodies of C3 and C4 is rectangular - vertical is shape. PMnG

has ended at least 2yrs before this age

progression from one cervical vertebral stage to another does not occur annually

the time spent in each stage varies, on average, from 1.5 to 4.2yrs depending on the stage.

Peak mand growth:

I. 2 yrs after CVMS1

II. 1 yr after CVMS2

III. During this year – CVMS3

IV. Occurred within 1 to 2 yrs - CVMS4

V. Ended at least 1yr ago – CVMS5

VI. Ended 2 yrs ago – CVMS6

9. Scammon curve

During puberty the growth velocity curve rises to a maximum and then begins to fall again.

The maximum rate of growth is the peak height velocity (PHV).


Growth curves for the maxilla and mandible shown against Scammon's curves. The growth of

the jaws is intermediate between the neural and general body curves. Growth in height does

correlate with growth of the jaws.

Clinical relevance of growth in orthodontic

1. Growth rotations and its influence on malocclusion

a) Posterior rotation

Patient develop increase anterior vertical face height

Patient develop increase lower incisor crowding

Difficult to maintain a positive OB as OB reduces with growth - may progress to a Sk AOB

and progressively retrusive chin. So treatment should be delayed to adulthood

Bite opening mechanics should be avoided,

Lower incisors should not be proclined beyond normal values.

It may need for Xtns for arch levelling

b) Anterior rotation

OB deepens with growth rotation and is difficult to reduce, developing deep OB and CI 11/2

incisal relationship may need a bite plane to prevent the OB reduction. So treatment should

be started as early as possible

May mask any slight maxillary AP growth inhibition achieved with HG


May develop lower incisor crowding

Slower space closure

Avoid Xtns for arch levelling

2. Influence of growth on treatment

Orthodontic treatment proceeds more quickly if carried out during active growth. Therefore,

the most favourable time for treatment is during PGS. Stephens & Houston 1985 noted that

growth during treatment facilitates:

i. OB reduction

ii. distal movement of posterior teeth

iii. space closure

iv. occlusal settling

v. functional appliance treatment

vi. use of RME

vii. Unlocking the occlusion during the growth spurt allow the correction to be

expressed at dental level when the skeletal relationship change. As O Brien mentioned in 2003 the

controlled gp showed favourable growth of their mandible however their OJ stayed almost the

same and this because the occlusal interlocking prevent the correction to occur.

3. Growth modification

In a growing patient, some modification of growth pattern is possible. Treatment such as

functional appliances (Tulloch 1998), HG (Mills 1978), protraction (Ngan 1997) and RME

(Wertz 1977) are all most effective during rapid growth.

4. Prognosis

In skeletal II or III cases, subsequent growth may tend to either improve or worsen the skeletal

pattern. Prediction of growth pattern may allow accurate assessment of whether a CIII

malocclusion may be treated orthodontically, or if later surgical treatment will be necessary, or

whether growth is likely to facilitate correction of SkII or if ortho treatment should aim to

camouflage skeletal pattern.

5. Retention & stability.

Growth continuing after orthodontic treatment may contribute to relapse, particularly in cases

where the malocclusion resulted from the growth pattern (Nanda 1992).


If occlusion well interdigitated, dentoalveolar compensation maintains occlusion, but where

capacity exceeded, relapse may occur Houston 1972

Late lower incisor crowding may occur as a result of long-term growth changes.

6. Orthognathic surgery.

Where surgery is planned, it is nb to ensure facial growth is complete, to avoid relapse caused

by subsequent growth.

Methods for Studying Bone GrowthTypes of growth studies

Longitudinal Cross sectional Mixed

A. Quantitative method:1. Direct Craniometry Anthropometry1. Indierect method:

Skeletal maturation or Comparative Anatomy like hand wrist and cvm Cephalometric analysis 3-D imaging via computed tomography (CT) or MRI, but it still can be helpful to use

implants to provide landmarks for superimposition Study model Photograph B. Experimental study

Vital Staining

Radioactive tracers and Technium 99

Implant Radiography: This method of study was developed by Professor Arne Björk

and coworkers at the Royal Dental College in Copenhagen, Denmark, and was used

extensively by workers there (see Chapter 4). It provided important new information

about the growth pattern of the jaws. Before radiographic studies using implants, the

extent of remodeling changes in the contours of the jaw bones was underestimated, and

the rotational pattern of jaw growth described in Chapter 4 was not appreciated.


Genetic study (Msx1 is the controlling gene for jaws)

The growth studies are Burlington (canada) , Broadbent (ohaio) and Iowa growth studie and it is consist of ceph and sm

These studies helped to understand the growth and develop slandered and template, growth direction , prediction of mandible growth peak growth by CVM and hand wrist


growth prediction (amount, direction and spurt) with relevance to orthodontics by almuzian

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