Shorts

The possibility that a distal step would become class II is very real, and this not self correcting problem. When the central incisors erupt, these teeth use up essentially all of the excess space in the normal primary dentition. With the eruption of the lateral incisors, space becomes tight in both arches.

Normal child will go through a transitory stage of mandibular incisor crowding at age 8 to 9 even if there will eventually be enough room to accommodate all the permanent teeth in good alignment. In other words, a period when the mandibular incisors are slightly crowded is a normal developmental stage.

Continued development of the arches improves the spacing situation, and by the time the canine teeth erupt, space is once again adequate.

Terms used to describe the position of teeth.

Mesioversion - A tooth in the arch located more mesial than normal
Distoversion - A tooth in the arch located more distal than normal
Labioversion - An incisor or canine outside of arch towards the lips
Buccoversion - A  posterior tooth outside the arch toward the cheek
Linguoversion - A  tooth inside the arch form toward the tongue
Infraversion  - A tooth that has not erupted to the occlusal plane
Supraversion - A tooth the has over-erupted
Torsiversion - A tooth rotated on its axis
Transversion (Transposition) - Teeth that are in the wrong sequential order.

The growth of the mandible generally follows the "general" body growth curve, which is distinct from the neural and lymphoid tissue growth curves described by Scammon's growth curves.

Lymphoid tissue grows very rapidly in childhood, reaching a peak larger than adult size before puberty, then shrinking.

Neural tissue grows rapidly early in life and reaches nearly adult size by about 6-7 years of age.

General tissues (including bone, muscle, and viscera) exhibit an S-shaped curve with rapid growth in infancy, a slower phase in childhood, and a pubertal growth spurt. The mandible's growth pattern most closely mirrors this general curve.

SOLUTION
· Pont’s in 1905 presented a system whereby the measurement of the four maxillary incisors automatically established the width of the arch in the premolar and molar region.  If measured value is less than calculated value, it indicates the need for expansion. 

· Linder Harth index: This analysis is very similar to Pont’s analysis except that a new formula has been proposed to determine the calculated premolar and molar value. 

· Korkhaus analysis: This analysis is also very similar to Pont’s analysis it makes use of Linder Harth’s formula to determine the ideal arch width in the premolar and molar region.
 In addition this analysis utilizes a measurement made from the midpoint of the inter-premolar line to a point in between the two maxillary incisors. 
 
· Bolton’s analysis: The Bolton’s analysis helps in determining disproportion in size between maxillary and mandibular teeth.