Frenulectomy of the tongue and the influence of rehabilitation exercises on the sEMG activity of masticatory muscles Simona Tecco a,⇑ , Aberto Baldini b , Stefano Mummolo c , Enrico Marchetti c , Maria Rita Giuca d , Giuseppe Marzo c , Enrico Felice Gherlone a a University Vita-Salute San Raffaele, I.R.R.C.S. San Raffaele Hospital, Milano, Italy b Unit of Orthodontics, University of Tor Vergata, Rome, Italy c Department of Life, Health and Environmental Science, University of L’Aquila, Italy d Department of Surgical, Medical and Molecular Pathology and Clinics, University of Pisa, Italy article info Article history: Received 19 July 2013 Received in revised form 6 April 2015 Accepted 7 April 2015 Keywords: Laser Orthodontics Lingual frenulectomy sEMG Masticatory muscles Sub-mental muscles Orbicularis oris muscle abstract This study aimed to assess by surface electromyography (sEMG) the changes in sub-mental, orbicularis oris, and masticatory muscle activity after a lingual frenulectomy. Rehabilitation exercises in subjects with ankyloglossia, characterized by Class I malocclusion, were assessed as well. A total of 24 subjects were selected. Thirteen subjects (mean age 7 ± 2.5 years) with Class I malocclusion and ankyloglossia were treated with lingual frenulectomy and rehabilitation exercises, while 11 subjects (mean age 7 ± 0.8 years) with normal occlusion and normal lingual frenulum were used as controls. The inclusion criteria for both groups were the presence of mixed dentition and no previous orthodontic treatment. The sEMG recordings were taken at the time of the first visit (T0), and after 1 (T1) and 6 months (T2) for the treated group. Recordings were taken at the same time for the control group. Due to the noise inher- ent with the sEMG recording, special attention was paid to obtain reproducible and standardized record- ings. The tested muscles were the masseter, anterior temporalis, upper and lower orbicularis oris, and sub-mental muscles. The sEMG recordings were performed at rest, while kissing, swallowing, opening the mouth, clenching the teeth and during protrusion of the mandible. These recordings were made by placing electrodes in the area of muscle contraction. At T0, the treated group showed different sEMG activity of the muscles with respect to the control group, with significant differences at rest and during some test tasks (p < 0.05). In the treated group, an increase in sEMG potentials was observed for the masseter muscle, from T0 to T2, during maximal voluntary clenching. During swallowing and kissing, the masseter and sub-mental muscles showed a significant increase in their sEMG potentials from T0 to T2. During the protrusion of the mandible, the masseter and anterior temporalis significantly decreased their sEMG activity, while the sub-mental area increased significantly. No significant change was observed in the control group during the follow-up. The sEMG potentials of treated patients at T2 reached about the same values as those of the control group at T2. At T0 and T1 the differences between the two groups were more diffused, suggesting a clinical improvement of muscular functions after treatment. Lingual frenulectomy and rehabilitation exercises seem to affect the function of the orofacial muscles. Improvement in muscle sEMG potentials after treat- ment was demonstrated by sEMG, which can be considered the correct method to monitor this intervention. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction Several studies have been undertaken for centuries to under- stand the relationship of form and function in orofacial develop- ment (Pagni and Baccetti, 1993). In growing patients, orofacial myofunctional therapy (OMT) in combination with conventional orthodontic therapy allows achiev- ing harmonious orofacial development during growing (Fournier and Girard, 2013). It is now well recognized that most dentomax- illofacial dysmorphism have a multi-factorial etiology. Among the environmental factors, uneven pressures caused by the behavior of the orofacial muscles are recognized as a dynamic cause. (Grabowski et al., 2007; Stahl et al., 2007). A correct function leads to trouble-free jaw development, whereas an impaired function http://dx.doi.org/10.1016/j.jelekin.2015.04.003 1050-6411/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: University Vita-Salute San Raffaele, Milano, Via Olgettina 60, Italy. E-mail addresses: tecco.simona@hsr.it, simtecc@gmail.com (S. Tecco). Journal of Electromyography and Kinesiology 25 (2015) 619–628 Contents lists available at ScienceDirect Journal of Electromyography and Kinesiology journal homepage: www.elsevier.com/locate/jelekin