Grave, Keith and Townsend, Grant: “Hand-wrist and cervical vertebral maturation indicators: how can these events be used to time class II treatments? Australian Ortho J. November 2003; 19:33-45.
Abstract by McGann
The use of wrist x-rays and cervical vertebra (visible on the ordinary ceph x-ray) for the use in timing class II growth correction is presented. Growth curves were established for 47 boys and 27 girls from longitudinal records taken from 1961-1971 in Northern Territory, Australia. There had to be a minimum of 3 wrist x-rays and 4 cephalometric x-rays, and height (stature) measurements during this period to be included in the study. The ossification events for the wrist and cervical vertebra methods were charted on these curves, paying attention to how the changes related to the pubertal growth spurt. Children reach adolescence at variable ages.
The authors cite literature studies of wrist and cervical vertebral maturation for various populations in the world, including Mexican, Spanish, Japanese and North American samples. Their findings are consistent with these studies. Researchers have argued about the precision of growth prediction, but these authors feel that the orthodontist does not require such precision, but instead just wants to know if there will be significant growth during the treatment period and use this for timing of class II treatment. A quick method of assessment is needed to make the use of these x-rays in clinical practice.
Prediction of the growth spurt can be helpful when using orthopedic appliances such as headgear (and functional appliances) to correct class II, and such a prediction should be present to decide which treatment appliance is to be used. Restraint of the maxilla with a headgear as the mandible grows uninhibited is the most common method to improve skeletal and dental class II, but is of course dependent on growth for success.
McGann note: Prediction of growth can also be used in class III treatment to assess the possibility of unaesthetic facial features and the need for a surgical approach to treatment. This information should be a part of any consultation with parents of growing class III children. I also use this growth information to determine if over-correction of class III to a 1-2mm class II dental occlusion is needed to account for mandibular growth in the retention phase.
Height velocity was calculated by dividing the height changes of the patient in an interval of time to determine the “rate” of growth. For example, if the patient grew 9cm between the ages of 13 and 14 years, then the rate of growth was listed as 9cm per year at age 13.5 years of age. Determination of Peak Velocity was important for development of the growth velocity curves, and was attained at the average age of 11.8 years for girls and 13.8 years for boys. The boys at this peak velocity grew at a rate of 10.3cm per year and the girls 8.5cm per year, with the maximum rate of mandibular growth corresponding to these changes in height.
On the lateral cephs, measurements were made from 1) Articulare to Pogonion 2) Pogonion to gonion, and 3) Articulare to gonion to define mandibular dimensions as recommended by Bjork.
The hand-wrist structures used to determine the ossification events were:
1. initial ossification of the pisiform. This occurs before peak growth velocity in almost all children.
2. initial ossification of the ulna metacaro-phalangeal sesamoid of the thumb (“sesamoid”). This becomes visible at peak growth.
3. attainment of epiphysis capingof its diaphysis in the proximal phalanx of the first finger (“growth plate” in my simple thinking). Caping happens near the peak growth, but is on the deceleration side of the curve.
4. complete epiphyseal union in the distal phalanx of the third finger. This follows the peak growth period in almost all children.
Ossification of the sesamoid and pisiform were related to the height velocity curves, showing an average of 1.3 years from pisiform ossification and 0.3 years (boys) and 0.5 years (girls) from sesamoid ossification before “peak” height velocity. Epiphysis caping and union (event 3+4 above) happened in the “decelerating” part of the growth curve.
Timing from the cervical vertebrae (C2,C3,C4) were defined by the concavity of the lower border as well as the shape of C3/C4 as 1) trapezoidal, 2) rectangular-horizontal, or 3) square or rectangular-vertical, using the work of Baccetti. There is a progressive deepening of the inferior concavities of C2/C3/C4 as the patient passes through the pubertal growth spurt. “CVM stages” were defined as:
CVM Stage 1: trapezoidal (early age). The vertebrae are “flat” on the inferior border with a possible slight concavity on the lower border of C2. The shape of C3 and C4 are a trapezoid.
CVM Stage 2: C2 now has a concavity on the inferior border with a slight concavity on C3. The shape of C3+C4 are now a trapezoid or rectangular-horizontal. The vertical height of the vertebrae is increasing.
CVM Stage 3: The concavities are now visible on all the vertebrae with the C2 concavity deepening. The vertebrae are now rectangular-horizontal (horizontal refers to the longest side of the rectangle being in the horizontal direction)
CVM Stage 4: The concavities of the 3 vertebrae are deepening with the shape becoming square. It is possible that C4 will still be rectangular-horizontal (height did not increase as much to make the square out the rectangle).
CVM Stage 5: The height of the vertebrae increases, making the shape of C3 rectangular-vertical (longest side of rectangle is now vertical). C4 can now remain square or also become rectangular-vertical. The concavity of C4 has deepened further.
CVM stages 1+2 preceded the peak growth period. Stages 3-4-5 in girls followed the peak growth velocity. In Boys, stage 4+5 definitely followed the peak, with stage 3 being variable.
The events of both the wrist x-ray and cervical vertebrae were plotted on the height velocity curve for boys and girls, relating these to the overall pubertal growth spurt. Combinations of the wrist and CVM events can be seen as they relate to the peak.
Mandibular growth was then plotted for boys and girls and related again to the wrist x-ray and CVM stages. The peak growth of the mandible was noted to each event. The peak growth of the mandible was at the same time as the peak growth in height, therefore making a practical diagnostic tool.
Boy mandible growth Girl mandible growth
Early maturing boy (mandible growth) Late maturing boy (mandible)
A series of wrist x-rays and height information can be recorded in the clinic to mark the take-off, peak, and slow-down phases of pubertal growth. Variability between children in age is a function of an “early maturer” or a “late maturer”.
Class II treatment can be started early, but there is a feeling that a “one-stage” treatment approach during adolescence is more efficient (vs. phase I+II treatment phases). Assessment of a patient’s cooperation level combined with growth prediction is important in treatment planning.
These authors recommend the following protocol for the start of Class II treatment timed to the pubertal growth spurt.
CVM stage 1: wait for at least 1 year before asking for another lateral ceph.
Combination Pisiform (wrist) + CVM stage 2: delay the orthopedic treatment phase.
Combination Sesamoid + CVM stage 2 in girls: start treatment
Combination Sesamoid + CVM stage 3 in boys: start treatment
Adding the wrist x-ray to the evaluation adds radiation exposure, but is less likely to be mis-interpreted than the CVM stages in the clinic. The depressions of the vertebrae are subtle changes. Care must be used to not obscure the vertebrae with the protective thyroid collar. The best assessment of growth is found when combining both methods, but this involves the most radiation exposure. The wrist x-ray is the best if you only have one choice as the events are more clear. The hand-wrist x-ray can also be used to estimate mature heights.
The author suggests that patients be referred to the orthodontic practice at an early age to start the “preparation phase”. The orthodontist gets to know the family and takes a lateral ceph and panoramic x-ray (not wrist x-ray). The cervical vertebrae evaluation is explained to the parent with the most efficient time to start treatment being CVM stage 2, as then the appliances can be worn for the shortest period of time (as in less $).
The patient is then put on a recall schedule, where a wrist x-ray is taken if the height growth history (register the height of the patient at each visit) indicates that the take-off stage is imminent. The combination of hand-wrist and lateral ceph evaluation can be used in the pre-treatment records for the orthopedic phase (probably a functional appliance or headgear with brackets to align).
After a period of about 15 months, extractions are reconsidered (class II remains), where a new ceph and panoramic x-ray are taken. The growth assessment is made at this time only from the cervical vertebrae (if growth is finished, then extractions are needed).
CVM stage 5 (end of growth) can be an influencing factor in the retention phase and in situations requiring implants.
Including the growth assessment to the treatment planning also has the added benefit of adding confidence to the treatment approach (for both the orthodontist and patient). Clinical efficiency can also be improved by adding growth curves to their clinical management.
McGann comments:
It cannot be denied that growth is an integral part of orthodontic treatment and should be considered in the clinical management and treatment planning for all class II and III cases. Including growth assessment can improve treatment efficiency and the overall success. The added benefits in confidence while looking good to our patients and peers should encourage all of us to add this information to our diagnosis. This paper presents a practical approach to do so in a busy practice.