Bite force assessment before and after orthognathic surgery in individuals with repaired cleft lip and palate

Objective To evaluate the impact of orthognathic surgery on the masticatory system of individuals with repaired cleft lip and palate (CLP) by means of bite force (BF) assessment. Material and methods Forty individuals were prospectively divided into 2 groups: 1) Control group (CON): 20 individuals without CLP (10 males, 10 females, 23.7y±7.4), 2) Cleft lip and palate group (CLP): 20 individuals with complete CLP with indication for orthognathic surgery (OS) (11 males, 9 females, 23.6y±5.6; 10 unilateral CLP; 10 bilateral CLP). The BF was evaluated in the immediate preoperative period (PRE), 3 months postoperatively (POST3M) and 6 months postoperatively (POST6M), using a gnathodynamometer (IDDK Kratos, Cotia-SP, Brazil). Results The BF of the CLP group was significantly lower than that of the CON in all evaluated periods. The BF of individuals with CLP was significantly lower in POST3M compared to PRE. Also, a significant increase in BF was observed between POST3M and POST6M. Though not significant, the BF was increased in POST6M when compared to PRE. The BF of unilateral and bilateral CLP individuals were statistically similar. Males presented a BF almost twice as high as females. Conclusion Cleft lip and palate negatively impacts BF. Although there was a tendency for BF values to increase 6 months after OS, it was still significantly reduced when compared to controls, not reaching normative values.