Genetics deals with the molecular structure and function of genes, gene behaviour in the context of a cell or organism (e.g. dominance and epigenetics), patterns of inheritance from parent to offspring, gene distribution, variation and change in populations. Genetics indeed has a very important role in orthodontics.Knowledge can help the orthodontist make an accurate diagnosis and plan and execute treatment with special strategies and considerations about clinical demands.However, contrary to the presumption that malocclusions of genetic cause are less amenable to treatment than those of an environmental cause, a change in environmental factors can affect a polygenic trait with a high estimate of heritability and that change can come in the form of a Treatment.