Theories Of Craniofacial Growth Explained

Theories Of Craniofacial Growth Explained

Write briefly on theories of growth.
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Describe in detail about theories of growth.
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Theories of Growth

Depending on the Area Where Growth Center Occur

• Genetic theory (Brodie)
• Sutural dominance theory (Sicher)
• Functional matrix theory (Melvin Moss)
• Cartilaginous theory (James Scott.

Based on other Concepts or Hypothesis Related to Craniofacial Growth

• Von Limborgh’s compromise theory
• Cybernetic theory (Petrovic)
• Hunter and Enlow’s growth equivalent concept.

Genetic Theory

• The genetic theory was given by Brodie (1941).
• As per the theory pattrn of facial confiuration is under genetic control.
• This theory was a complete assumption and had no proofs.

Sutural Dominance Theory

• This theory was given by Sicher.
• Theory was adhered to the belief that within each suture resided the genetic information which determines the amount of growth occurring at the site of suture.
• As per the theory suture was regarded as the growth center which generate tissue separating forces.
• The theory is disapproved now and researches show that suture act as growth sites and not the growth centers.

Functional Matrix Theory

The functional matrix theory is given by Melvin Moss and is truly based on work done by Van der Klaauw. The theory states that, “There is no direct genetic inflence on the size, shape or position of skeletal tissues, only the initiation of ossifiation. All skeletogenic activity is primarily depends upon the functional matrices”.

Cartilaginous Theory

• According to the cartilaginous theory intrinsic growth controlling factors are present in the cartilage and in periosteum with sutures which has only secondary adaptive role.
• As per Scot the cartilaginous parts of skull act as primary center of growth.
• Scot suggested that primary cartilage present in the nasal septum is main mechanism responsible for growth of nasomaxillary complex. In mandible condylar cartilage is considered as growth center present bilaterally with Unshaped mandible in between.

Van Limborgh’s Compromise Theory

• As per Van Limborgh process of growth and development occur in conjunction with three theories. He accept functional matrix theory, sutural theory and genetic theory.
• He proposes fie factors of growth which controls it, i.e.
  • Intrinsic genetic factors: Genetic factors which are inherent to craniofacial skeletal tissues.
  • Local epigenetic factors: These factors are genetically determined inflences which originate from adjacent structures and spaces such as brain, eyes.
  • General epigenetic factors: Genetically determined inflences originate from distant structures, such as sex hormone, growth hormones, etc.
  • Local environmental factors: These are local non-genetic inflences from the external environment.
  • General environmental factors: These are general nongenetic inflences from external environment.

Cybernetic Theory

According to Pavlov everything affcts everything and living organisms never operate in open loop mechanism. In an open loop mechanism, the input leads to a response and there is no feedback or regulation.

Enlow’s Growth Equivalent Concept

• As per Enlow growth of a given regional part is compared with its specific counterpart, i.e. growth equivalent.
• A dimensionally balanced growth occur when each regional part and its particular counterpart enlarges to same extent.
• Imbalance in growth causes protrusion or retrusion of part of face.