On Muscular Factor Question in the Correction of Transversal Incisor Occlusion

Abstract

The aim of our study was to evaluate the role of the muscle factor and the effectiveness of manual treatment of masticatory muscle dysfunction in patients with transversal incisor occlusion (TIO). Methods and Results: We examined and treated 35 patients aged 18-25 years with clinical signs of TIO in the clinic of orthopedic dentistry. Diagnostic methods for TIO included an interview, face and oral cavity examination, and clinical functional tests. Occlusion was assessed using anthropometric measurements and examination of plaster jaw models in an articulator for additional diagnostics of the dental factor; a radiological method (jaw orthopantomography with the inclusion of articular joints) was also used for the articular factor diagnostics and examination of masticatory muscles and neck muscles. The treatment methods included manual treatment of masticatory muscle dysfunction: "myofascial trigger point release technique," "stretching-push," and "post-isometric relaxation." All patients' complaints were mainly confined to improper occlusion of the front teeth, namely, a misalignment of the centerline between the upper and lower anterior teeth. Moreover, 71.4% of patients noted intermittent clicking in one or both articular joints of the temporomandibular joint, 42.8% of patients reported pain in the region of one temporomandibular joint, 28.6% of patients noted noise in the ear of the same joint, as well as discomfort while chewing. On external examination, all patients had a slight asymmetry of the lips and cheeks on the habitual chewing side. The apex of the chin was positioned slightly to the side relative to the facial midline. All patients had a disturbed movement trajectory of the lower jaw. During mouth opening, the lower jaw trajectory changed relative to the facial midline: at first, it was straight, for a very short period, and then it deviated sideways, after which it returned to the center. There was a misalignment of the central line of the lower dentition relative to the midline of the face in the anterior region. The radiological picture showed signs of articular joint dysfunction: difference in the size of the articular gaps on the right and left sides. After a single session of manual treatment of masticatory muscles, all patients noted that the improper occlusion of the front teeth was corrected, pain and clicking sensations in the TMJ disappeared in 42.8% of patients, and pain disappeared in the area of one joint, along with noise in the ears and chewing discomfort. Headache in the parietal and temporal areas disappeared. The trajectory of lower jaw movements during mouth opening normalized in all patients after the performed manual treatment. Conclusion: We can conclude that when diagnosing and treating occlusal disorders, it is necessary to pay attention not only to the position of the teeth and the TMJ elements, but also to the muscular factor – the condition of the masticatory muscles. Special attention should be paid to the condition of the lateral wing muscles.