Mandibular incisor extraction--postretention evaluation of stability and relapse

Area of Science:

• Dentistry
• Orthodontics
• Dental Public Health

Background:

• Orthodontic treatment often involves tooth extraction to alleviate crowding or correct malocclusion.
• Mandibular incisor extraction is a less common approach compared to premolar extraction.
• Long-term stability and alignment outcomes following mandibular incisor extraction require further investigation.

Purpose of the Study:

• To evaluate the long-term postretention stability and alignment of mandibular incisors after orthodontic treatment involving single or double mandibular incisor extraction.
• To compare the outcomes with previously reported results from premolar extraction cases.

Main Methods:

• Retrospective evaluation of pretreatment, posttreatment, and 10-year postretention dental casts and lateral cephalograms.
• Analysis of 42 patients treated with edgewise orthodontics, including single (n=24) or two (n=18) mandibular incisor extractions.
• Assessment of mandibular incisor alignment, intercanine width, overbite, and overjet.

Main Results:

• Unacceptable mandibular incisor alignment was observed in 29% of single-incisor extraction patients and 56% of two-incisor extraction patients at 10-year postretention.
• These rates are more favorable than the 70% unacceptable alignment reported for premolar extraction cases.
• Intercanine width decreased during treatment and continued to decrease postretention; overbite and overjet remained acceptable.

Conclusions:

• While mandibular incisor extraction may yield more favorable long-term alignment than premolar extraction, a significant percentage of patients still experience alignment issues.
• Further research is needed to identify predictors of relapse and optimize treatment protocols for mandibular incisor extraction cases.
• Long-term stability of intercanine width should be considered in treatment planning.