Neuromuscular diagnosis in orthodontics: effects of TENS on maxillo-mandibular relationship

This study was conducted in order to assess the changes in the occlusal position of the mandible after Ultra Low Frequency (ULF)-TENS relaxing procedure in children with diagnosed functional mandibular lateral deviation.

This study was performed on 20 children, aged between 8 and 12 years, with a mean age of 10 years (SD 0.79) with functional mandibular lateral deviation, diagnosed by clinical and cephalometric evaluation, referred to the Dental Clinic for paediatric dental care. Diagnostic neuromuscular registrations were made for all children, and their casts mounted on articulator Galetti at the myocentric position and compared to casts provided of a wax bite registration in intercuspal position.

The alignment of the midline after TENS was not punctual (p >0.05). Compared with the existing intercuspal position, neuromuscular registration showed improvement in 10 (50%) patients, 6 patients (30%) showed no changes, while worsening of the tooth-midline discrepancy was assessed in the remaining 4 (20%). The molar relationship did not follow the same trend of the midline because of the three-dimensional changes in the maxillo-mandibular relationship induced by TENS. After TENS there was a significant correlation between midline and right side deviation (r >0.65), there was no correlation between midline and the left side (r <0.65). Furthermore, right molar movement showed no correlation with the contralateral molar (r <0.65). The posterior areas of the arch were moving in a very unpredictable way, resulting in the diagnosis and prognosis of mandibular lateral deviation as absolutely individual and unpredictable. Conclusion This study suggests that TENS recorded occlusion is an interesting diagnostic approach in orthodontics since it allows visualising the trends of the neuromuscular system.