Читать книгу Orthodontic Treatment of Impacted Teeth - Adrian Becker - Страница 45

When an archwire is inserted into a series of malaligned brackets, it will produce both forces and couples at each bracket. When both the force and the moment at the bracket are in the correct direction in relation to their suitability to produce the desired tooth movement, the force system is termed consistent [1, 2]. If only some forces or moments are in the required direction, the force system is considered inconsistent [1, 2]. Consistency, therefore, usually refers to a force system where both forces and couples are needed.

Sometimes, however, either the applied force or the couple may not be required or they may produce an undesired side effect. In addition, if a side effect force or couple is present, the force system will also be considered inconsistent [1, 2]. Inconsistency is often the reason why a straight‐wire appliance may encounter a poor response [1, 2].