The science behind bracket bases
Canines are the longest teeth in the human dentition and good control is essential. Following computer analysis of enamel anatomy, all bases used in the Mini Sprint II range were redesigned. This has been particularly helpful for canines, which have a curved labial surface.
These new bases have proved to be a big advantage. The snug fit helps to express the prescription accurately and ensures better retention.
Upper canine tip, angulation, and in-out
Canines should be and are the thinnest brackets in the upper arch. Routine upper canines have -7° torque and +8° angulation. The minimal settings are essential to avoid excess thickness of brackets on other teeth which would reduce tooth control.
The -7° upper canine bracket has been a cornerstone of our treatment method since 1997 and is the bracket of choice for most cases. After rapid maxillary expansion (RME) it is helpful to use -7° torque brackets to achieve good root correction without wire bending. (Fundamentals of Orthodontic Treatment Mechanics, page 59).
The +7° torque option
The upper canine bracket can be inverted, which gives +7° torque and +8° angulation. In cases with buccally ectopic canines this is a useful option to guide the root into cancellous bone without wire bending. The +7° torque is also used in cases where there is agenesis of the upper lateral and the space is to be closed, bringing the canine into contact with the upper central.
The zero torque canine bracket
The zero torque option is helpful after premolar extractions. These cases may have slightly narrow or small maxillas and the treatment often involves correction of canine root tip, or bodily retraction of canines. The canine roots need to be in cancellous bone for effective movement. The zero torque bracket, or sometimes the +7° option, are helpful to achieve this without wire bending.
The upper left canine bracket and premolar brackets. The -7° torque bracket can be inverted to give +7° and guide the root into cancellous bone, depending on the needs of the case. The canine bracket is available with or without a hook. If it has a hook this needs to be removed if it is planned to invert the bracket.
In cases with buccally ectopic canines the -7° torque bracket is often inverted to give +7° and guide the root into cancellous bone. Inversion is also helpful where there is lateral incisor agenesis and it is planned to close space, bringing the canine into contact with the central incisor.
The System 5.0 treatment method has three torque options for the upper canines. This provides great versatility and minimises wire bending. (Not to scale).