Orthodontic uprighting of a mesially tipped mandibular second molar into the space of a missing first molar is likely to produce which side effect at the molar?

Correct answer: A. Extrusion of the molar

• A. Correct. Uprighting a mesially tipped molar tips the crown distally, and in doing so the tooth EXTRUDES — the mesial marginal ridge and cusps move occlusally. This is a predictable and clinically important consequence: the extruded molar develops a premature occlusal contact and almost always requires occlusal equilibration or a restoration after uprighting. The distal crown movement also opens the space and reduces the overbite in that segment.
• B. Uprighting mechanics do not intrude the molar; intrusion requires specific vertical anchorage.
• C. Vertical change is exactly what does occur — extrusion is the hallmark side effect.
• D. Overbite in the anterior segment is reduced, not increased, by this mechanics.