Long-Term Neuromuscular Status in Overdenture and Complete Denture Patients with Severe Mandibular Atrophy

Purpose: The long-term neuromuscular status of edentulous patients with severe mandibular atrophy who wore complete dentures (CDs) or implant-supported overdentures (ISOs) was investigated in the present study. Materials and Methods: Eleven CD patients and 11 patients with ISOs supported by two implants took part in the study. All patients had used their dentures for more than a decade. All patients (average age, 76 years) suffered from severe mandibular atrophy, which was to be quantified using panoramic radiographs and computer software. Kinesiographic parameters such as opening and extension movements as well as opening and closing velocities were recorded by means of a sirognathograph during test food chewing on the left and right sides. Simultaneously, electromyographic recording of masseter and temporalis activities was performed using surface electrodes. Results: The kinesiographic values obtained from ISO patients were higher than those for CD patients: 12.65 mm for vertical opening (CD, 11.79 mm) and 5.66 mm for horizontal extension (CD, 5.11 mm). Opening velocity values were 100.93 mm/s and 91.74 mm/s, respectively. Closing velocity of 78.16 mm/s in ISO patients was significantly different from that measured in CD patients (58.45 mm/s). With regard to electromyographic activities, the increase was significant for the masseter during chewing on the working side (ISO: 189.79 µV, CD: 78.05 µV) and on the nonworking side (ISO: 130.53 µV, CD: 47.25 µV). For the temporalis, values of 194.11 µV and 119.02 µV in the ISO and CD patients, respectively, were observed for working side chewing. Nonworking side values reached 155.48 µV for ISO subjects and 78.35 µV for CD subjects, which was significantly different. The degree of atrophy in both groups did not differ statistically. Conclusions: The use of two interforaminal implants with an overdenture can provide long-term neuromuscular benefits for edentulous patients. Keywords: complete denture, electromyography, implant overdenture, neuromuscular activity, sirognathograph