Journal
EUROPEAN JOURNAL OF ORTHODONTICS
Volume 36, Issue 6, Pages 672-677Publisher
OXFORD UNIV PRESS
DOI: 10.1093/ejo/cjt094
Keywords
-
Categories
Funding
- Foundation for Orthodontic Research & Education (FORENZAO) Trust via the Education Research and Development Group (ERDG) of the New Zealand Association of Orthodontists (NZAO)
- Fuller Scholarship through the Sir John Walsh Research Institute (SJWRI) of the University of Otago
Ask authors/readers for more resources
OBJECTIVES: During orthodontic arch expansion, the teeth are displaced against the perioral soft tissues. This can affect the equilibrium of forces that are thought to act on teeth, with consequent implications for long-term stability. The aim of this study was to investigate the effect of incremental lower lip advancement on intraoral pressure and electromyographic (EMG) activity of the lower lip. MATERIALS AND METHODS: Intraoral pressure and EMG activity was measured in 10 participants (2 males, 8 females; 22 years +/- 7 months) as the lower lip was incrementally advanced using three custom-made vacuum-formed stents of differing labial thicknesses (0.5, 2.5, and 4.5 mm). A task paradigm including at rest recordings and maximal voluntary contraction was completed for each tray. RESULTS: Resting lip pressure generated increased as the lower lip was advanced (P < 0.001). The EMG activity of the lower lip increased significantly (P < 0.001) only once the lip was advanced from 2.5 to 4.5 mm. For the pressure recordings, the response to incremental lip advancement showed considerable individual variation. CONCLUSIONS: These findings suggest that the initial pressure increase on the lower incisors was mostly likely due to the inherent viscoelastic properties of the lower lip, while the pressure increase between the 2.5 and 4.5 mm advancement was due to increased muscle activity. Each individual also responded to lower lip advancement in a different yet subject-specific manner.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available