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Updated: Aug 5, 2026
Single-stage Dynamic Reanimation of the Smile in Irreversible Facial Paralysis by Free Functional Muscle Transfer
Published on: March 1, 2015
State-of-the-art analysis of facial expression dynamics in unilateral cleft lip and palate cases using 4D imaging
Jessica Monaghan1, Ashraf Ayoub2, Philip Benington1
1Orthodontic Department, Glasgow Dental Hospital & School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Aim:
To investigate the dynamics of lip movement, including the duration, magnitude and speed, in surgically managed patients with unilateral cleft lip and palate (UCLP) using sophisticated three-dimensional real-time video imaging of the face (4D).
Materials And Methods:
A retrospective comparative study of 31 surgically managed UCLP cases and 34 age and gender matched non-cleft cases. The maximum smile dynamics, including speed, magnitude and duration, were assessed using 4D stereophotographic images captured using a pair of video cameras at 60 frames/sec. A 3-second smile yielded 180 3D images for analysis. A set of digitised landmarks was used to assess the dynamics of maximum smile.
Results:
The duration of the smile in cases with no cleft was much shorter than in the cases with UCLP (1.3 vs. 2 s). A measurable asymmetry was observed in the speed and magnitude of the philtrum between the two sides, with the cleft side being significantly slower (cleft 7.24 mm/s and non-cleft 8.22 mm/s). The speed of the lower lip landmarks was significantly greater on the cleft side (20.98 mm/s) than on the non-cleft side (19.22 mm/s). The speed and magnitude of movement for all upper lip landmarks in the cases with UCLP were significantly slower than in cases without cleft.
Conclusion:
Reduced speed and magnitude of lip movements in the cleft side of the upper lip indicates a restriction in muscular activity. This is likely to be due to lip scarring and incomplete repair of the muscles that contribute to distorted lip movement with maximum smile.
