| 摘要 |
The content of the present invention is a "differential archwire", to be utilized as a component of the fixed orthodontic appliance. The "differential archwire" is utilized to retract the incisors, and it can be used in association with the brackets today available on the market. The "differential archwire" is characterized by an anterior segment (11) with big cross-section area, and by two posterior segments (12,13) with smaller cross-section area. The anterior segment (11) completely fills the slot of the brackets of the incisors, and gives good control of the torque of the incisors during their retraction. The posterior segments (12-13) have smaller cross-section area in order to reduce the friction and to allow good sliding of the archwire along the brackets of the posterior teeth, canine, premolars, molars. The "differential archwire" is constituted preferably, but not necessarily, by stainless steel. The shape of the cross-section of the differential archwire is preferably, but not necessarily, rectangular with the long side of the rectangle placed along the horizontal plane. This design of the cross-section shape gives higher rigidity to the archwire along the horizontal plane, in order to help to keep a correct transversal diameter of the dental arches during the closure of the spaces present in the dental arches.
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