By Dr. Shaun Weng
Published June 2026
10 min read
Clinical Summary
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Content
Premolar extraction protocols Part 1 - What you may not know…
Extraction cases with aligners is challenging and results in:
• Extrusion of incisors, mesial crown tipping of posterior teeth, intrusion of premolars (bowing effect) and uncontrolled tipping of incisors
• Bowing effect is commonly seen in extraction cases or when closing large spaces with aligners
• Mesial crown tipping of the posterior teeth and anterior extrusion during retraction.
In general, there are two types of extraction protocols
• “M Pattern” vs “Frog Pattern”
“M Pattern”
• One step protocol, retraction of canine followed by en-masse of anterior four teeth
• Canine distalise to middle of the extraction space and then all anterior 6 teeth retracts together
“Frog Pattern”
• Multi-step protocol, canine retracted to half of extraction space → incisors retracted until contact with canine → canine continue to retract half of the residual space → All anterior teeth then retracts at the same time
So...M pattern vs frog pattern Which one is better?
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