Understanding Butler’s Field Theory And Dental Variability

Understanding Butler’s Field Theory And Dental Variability

Write about Butler’s field theory in Genetics.
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Write short note on Butler’s field theory.
Answer. Human dentition is divided into four fields, i.e. incisor, canine, premolar and molar. Most distal tooth in each field is the most susceptible to changes or variations. Changes are absence of tooth, variation in size, shape and structure. Accordingly, lateral incisors, second premolars and third molars are the most variable in their group. This is known as Butler’s fild theory.

• Here, canine is the least variable tooth in the arch.
• Butler’s field theory does not apply in lower anterior region, where mandibular central incisor is more commonly missing than lateral incisor.

Example 1

Within Molar/Premolar Field: According to Butler’s fild theory, maximum variability will be seen for the third molars. Third molars are the most common teeth to be congenitally absent and to be impacted.

Variability of third molars includes:

• Variability in size
• Third molars can be small appearing as microdonts. They can have small roots and small cusps.

Variability in Form

• They may have well formed cusps or several small tubercles.
• Some maxillary third molars may not resemble any of the teeth and appear like abnormalities.
• The roots can be very short, long often fused, may be separate and sometimes an extra root can be seen.

Example 2

Within incisor field, according to Butler’s field theory, the maximum variability will be seen for the lateral incisor.

Variability of lateral incisor includes:

• Peg-shaped lateral incisor.
• Congenitally missing laterals.

Example 3

• Within canine field.
• Canines, especially in maxillary arch can be impacted or ectopically erupted.