Korean J Orthod.  2004 Dec;34(6):497-505.

The long-term stability of the lower incisor axis in Class II division 2 malocclusions

• Choi WC
• Kim TW

Abstract

The purpose of this study was to evaluate the post-retention stability of the lower incisor axis in Class II division 2 malocclusions. The dental casts and lateral cephalograms from before (T1) and after (T2) orthodontic treatment and long-term post-retention (T3) in 62 Class II division 2 malocclusion cases were included in this study. After several linear and angular measurements at each time were taken, the significance in the amount of change of the lower incisor axis for each gender and extraction versus non-extraction was evaluated. The results showed that the lower incisors that inclined labially during treatment were unstable and relapsed to the original lingual position in Class II division 2 malocclusions (p < 0.001). There was no significant difference between extraction and non-extraction groups for the amount of lingual relapse of the lower incisors (p > 0.05). There was no significant difference between male and female groups for the axial change of the lower incisors (p > 0.05). As a result of multiple regression analysis, the cephalometric measurement best predicting the lower incisor position to the A-Pog line post-retention was pre-treatment L1-Apog(mm) and pre-treatment SNGoMe(degrees ). Because of the instability of labially inclined lower incisors after orthodontic treatment, the treatment goal should be the pre-treatment incisor axial position.

Keyword

Stability; Lower incisor axis; Class II division 2 malocclusion

MeSH Terms

Axis, Cervical Vertebra*
Female
Humans
Incisor*
Male
Malocclusion*
Recurrence