Biomechanical effects on maxillary protraction of the craniofacial skeleton with cleft lip and palate after alveolar bone graft

Zhengxi Chen, Xiaogang Pan, Qinghua Shao, Zhenqi Chen
Journal of Craniofacial Surgery 2013, 24 (2): 446-53

OBJECTIVE: To explore the biomechanical effects of maxillary protraction on the craniofacial skeleton in patients with unilateral cleft lip and palate (UCLP) after alveolar bone graft (ABG) and resorption of ABG, thus to provide theoretical basis for the clinical application of maxillary protraction, which can improve the facial deformity of the UCLP patients.

METHODS: A finite element model of a UCLP patient's skull was generated using data from spiral computed tomographic (CT) scans. Based on this finite element model, another 6 ABG finite element models were constructed to simulate ABG and resorption of ABG, respectively (nonresorption model, upper one-third resorption of the grafted bone model, upper two-thirds resorption of the grafted bone model, lower one-third resorption of the grafted bone model, lower two-thirds resorption of the grafted bone model, upper one-third and lower one-third resorption of the grafted bone model). Two additional models were developed to simulate maxillary protraction with expansion and maxillary protraction alone. All models were loaded with orthopedic force (30 degrees downward and forward to the occlusal plane, 500 g per side) on the region of alveolar of maxillary canine.

RESULTS: Before ABG, the cleft side showed larger displacement than the noncleft side, when it came to the stress distribution in the craniofacial suture, it showed an asymmetric pattern as well. After ABG, the displacement difference between the cleft side and the noncleft side decreased, and the stress distribution in the craniofacial suture showed more symmetric than that before ABG. The pterygopalatine suture obtained the largest value, followed by zygomaticotemporal, zygomaticomaxillary, and zygomaticofrontal sutures among the observed sutures. Higher stresses and pronounced forward displacement were generated in the craniofacial sutures after maxillary protraction with expansion.

CONCLUSIONS: Maxillary protraction after ABG performed a more favorable outcome. Among the ABG models, nonresorption model showed the best effect after loading maxillary protraction force, and resorption in the lower region of the grafted bone showed a better effect than resorption in the upper region of the grafted bone. Maxillary expansion could effectively facilitate the orthopedic of the maxillary protraction presumably.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"