Dental arch changes in postretention in Class II division 1 extraction cases

Area of Science:

• Orthodontics
• Dental Arch Stability
• Class II Malocclusion Treatment

Background:

• Class II division 1 malocclusion often requires complex treatment.
• Four bicuspid extraction and edgewise technique are common treatment modalities.
• Understanding postretention stability is crucial for long-term treatment success.

Purpose of the Study:

• To evaluate the long-term postretention stability of dental arches.
• To assess changes in arch dimensions and alignment after treatment with four bicuspid extractions.
• To analyze the stability of overjet and overbite in treated Class II division 1 patients.

Main Methods:

• Digital caliper analysis of dental casts from 29 Class II division 1 patients (skeletal type II).
• Measurements included intercanine width, intermolar width, arch length, irregularity index, overjet, and overbite.
• Data collected at pretreatment, posttreatment, and postretention (mean 4.15 years), analyzed using Student's t-tests (P<0.05).

Main Results:

• Intercanine widths increased post-treatment then decreased in retention; no significant long-term change. Intermolar widths and arch lengths significantly decreased post-treatment and in retention due to extraction space closure.
• Irregularity index improved post-treatment, with slight increases in crowding at postretention (75.86% mild crowding).
• Overjet and overbite decreased post-treatment but showed a tendency to increase during retention.

Conclusions:

• Dental arch changes were minimal during the postretention phase.
• A tendency for arches to revert towards their original positions was observed.
• The overall postretention stability of Class II division 1 cases treated with four bicuspid extractions is considered relatively good.