Changes in the Bioelectric Activity of Musculus Masseter in Case of Mandible Edentulousness Treatment

Abstract

The objective of the research: to define the dynamics of changes in bioelectric activity of mm. masseter dexter et sinister in patients with mandible edentulousness treated by means of four implant-supported dental prostheses of various types.
 105 patients were examined at the premises of the Center of Dentistry of the University Clinic of Ivano-Frankivsk National Medical University. 30 individuals out of 105 at the age of 23-28 with intact dentition, without somatic pathology were included in the control group.
 75 patients with mandible edentulousness underwent clinical examination, prosthodontic treatment, and follow-up. 3 clinical groups (Group I; II; III) were formed from this cohort of patients depending on the structural features of the manufactured dental prostheses.
 We conducted electromyography of mm. masseter dexter et sinister to the patients of the examination groups (n = 75) and the control group (n = 30) in order to achieve the objective of the research. The examination was performed by means of two-channel electroneuromyographic complex “Neuro-EMG-Micro” (“Neurosoft”) in the functional diagnostics office at the premises of the Department of Dentistry of Postgraduate Study Faculty at IFNMU.
 Quantitative indicators of bioelectrical activity of the right and left masticatory muscles were analyzed. Namely, the average values of the maximum amplitudes (μV) when performing the test of maximum bite force were analyzed. Recording of electromyographic indicators was performed before the prosthodontic treatment, 14 days after the fixation of the dental prosthesis, in 6 months and 12 months after the dental prosthesis functioning in order to study the dynamics of changes in the indicators of the examination groups.
 Electromyography recording and analysis of the findings in the individuals of the control group was performed once.
 Analyzing quantitative indicators of electromyographic examination significant differences in the dynamics of an increase in the indicators in 12 months compared to the initial indicators depending on the type of fixed dental prosthesis (subgroup A рІ-ІІІ<0.001; subgroup B рІ-ІІІ<0.001) and the order of prosthodontic treatment (рА-Б <0.001 for all groups of patients) were observed.
 
 Despite the fact that bioelectric indicators of mm. masseter dexter et sinister activity in the patients of the examination groups approximated to the indices of the control group, the dynamics of change was not equivalent and depended on the type of the dental prosthesis.
 The dynamics of an increase in the indicators of the patients in the examination groups differed by growth, however, the greatest increase was recorded in the period of “14 days” – “6 months” after the fixation of the dental prosthesis.
 On performing the test of maximum bite, the indicators of the masticatory muscles bioelectrical activity increased during the period named “before the treatment” – “12 months of functioning” most of all in IIIA examination group – by 66.52% (рd<0.001) on the right and by 76.37% (рd<0.001) on the left; and IIIB examination group – by 61.63% (рd<0.001) on the right and 67.20% (рd<0.001) on the left. The lowest indicators have increased in patients of IA examination group – 39.98% (рd<0.001) on the right and 39.95% (рd<0.001) on the left and IB examination group – by 32.48% (рd<0.001) on the right and by 34.75% (рd<0.001) on the left.