Second permanent molar extraction and late lower arch crowding: a ten-year longitudinal study

Area of Science:

• Orthodontics and Dental Arch Development
• Long-term Effects of Tooth Extraction

Background:

• Second molar extraction is a treatment option in orthodontics.
• Understanding the long-term stability of lower arch alignment after this procedure is crucial for treatment planning.

Purpose of the Study:

• To evaluate the long-term effects of second molar extraction on lower arch alignment.
• To assess changes in lower arch crowding and alignment over five and ten years post-extraction.

Main Methods:

• Study included thirty subjects who underwent four second permanent molar extractions around age 13.9.
• Lower arch alignment was measured using study models five and ten years after extractions.
• No mechanical treatment was performed on the lower arch; some subjects received simple upper arch treatment.

Main Results:

• A small average decrease in lower arch crowding was observed in the first five years post-extraction.
• Minimal to no significant changes in lower arch alignment were noted between the five and ten-year marks.
• Upper arch treatments varied, with five subjects having first premolar extractions.

Conclusions:

• Second molar extraction can lead to a modest, short-term improvement in lower arch crowding.
• Lower arch alignment appears relatively stable in the long term following second molar extraction without orthodontic intervention.