Although orthodontics mean smooth teeth as word meaning, it is dentistry field caring about correcting growth disorders of face and jaw as well as teeth irregularities (malocclusion).
Basic purpose of orthodontic treatment is a nice closing. It is conformity of regularly aligned teeth to teeth in opposite jaw. A nice closing facilitates biting, chewing and talking. Another important purpose is to form a permanent oral health. Food residues may be accummulated on the surfaces since irregular teeth are cleaned harder and therefore they may get decayed faster.
Correcting the teeth and making them more easily cleanable are required for better oral health. Moreover orthodontic treatments help to minimize gingiva diseases and bone losses to occur by stress in gingiva and alveol bone onwards in mouths, which do not have good closing.