Effect of Lip Muscles on Maxillary Growth in Cleft Lip and Palate Patients: Electromyographic Study

Abstract

Maxillofacial deformities in patients with CLP are suspected to result from congenital dysmorphogenesis, and aberrant postnatal growth in addition to postsurgical scar formation resulting from lip or palatal repair. Patients with unrepaired CLP present a nearly normal growth of the midface and dental arch. Surgical repair of the lip, palate, or both has been implicated to cause midfacial retrusion. Whether lip repair alone has a true major role in causing midface hypoplasia in clefted patients is a topic of much controversy. The current study aimed at verifying the effect of lip repair on the midface growth in patients with CL/P by correlating the results of electromyographic assessment of superior orbicularis oris muscle with the lateral cephalometric readings. A comparison was done between BCLP with/without hypoplasia, UCLP with/without hypoplasia, isolated CL patients and nonclefted individuals. Upper lip EMG activity during lip pouting was significantly increased in BCLP with hypoplasia (gp IB), BCLP without hypoplasia (gp IIB) and nonclefted (gp IIIB) subjects when compared to isolated CL (gp IIIA), UCLP with hypoplasia (gp IA) and UCLP without hypoplasia (gp IIA) subjects respectively. There were no statistically significant differences in the EMG values neither between the BCLP with and without hypoplasia nor between UCLP with and without hypoplasia. On the other hand, the BCLP and UCLP with hypoplasia groups suffered from retrognathic maxilla while BCLP without hypoplasia group had a prognathic maxilla and UCLP without hypoplasia had a normally positioned one. The only significant difference in EMG between the isolated CL group and the other groups was the difference between isolated CL and BCLP with maxillary hypoplasia. There were highly statistically significant differences between isolated CL group and BCLP/UCLP with hypoplasia in SNA and ANB angles.