The MBT appliance is a straight wire bracket system developed by McLaughlin, Bennett and Trevisi. It builds tip, torque and in-out values into the bracket and is designed around light continuous forces and sliding mechanics, so that the clinician needs fewer bends in the wire.
From edgewise to straight wire
Angle's edgewise appliance, introduced in the early twentieth century, relied on bends placed by the clinician in every archwire. In the 1970s Lawrence Andrews put the tooth specific values into the bracket itself, which led to the straight wire appliance and to his six keys to normal occlusion. A flat archwire in a well positioned bracket could now express the correct tooth position.
What the bracket prescription does
A prescription is a set of values built into each bracket: tip (mesiodistal angulation), torque (labiolingual inclination) and in-out (the thickness that compensates for the buccal contour). Because the bracket carries these values, the position of the bracket on the tooth decides how well they are expressed. A bracket placed too high or tilted will express the wrong values however good the wire is.
How MBT adapted the Andrews prescription
MBT modified the earlier prescriptions, adjusting torque and angulation values to counter unwanted incisor proclination during levelling and space closure, and it paired the bracket with a treatment philosophy: light continuous forces, a defined wire sequence, and attention to anchorage. The system is available with both 0.018 and 0.022 inch slots (see the slot size guide).
What it means for a general dentist
A single prescription with a defined wire sequence gives a beginner a consistent path from the first archwire to finishing. Accurate bracket placement matters more than any other single step, which is why the bonding protocol is taught early.
The limits of any appliance
No bracket system replaces diagnosis. Anchorage, growth pattern, case selection and patient cooperation decide the result, and these are covered through the biomechanics sessions of the course.
Key takeaways
- Straight wire brackets carry tip, torque and in-out values, so bracket position is critical.
- MBT is both a bracket prescription and a light force treatment philosophy.
- Choose one system and learn its wire sequence thoroughly.
Frequently asked questions
Is MBT a bracket or a technique?
It refers to both: a bracket prescription and the treatment philosophy built around it, which emphasises light continuous forces, a defined wire sequence and anchorage control.
What slot size does the MBT system use?
The MBT prescription is offered in 0.018 and 0.022 inch slots, and the 0.022 inch slot is the more widely used of the two.