Impact of Overbites and Overjets on Selected Stomatognathic Muscle Activity
Dr n. med. Piotr Jacuński, Assoc. Prof. Joanna Kuć, Dr. Marcin Chorzewski, Prof. Teresa Sierpińska,
Medical University of Bialystok
Objectives
Assessment of the relationship between overbite and overjet and the activity of selected muscles of the stomatognathic system in a group of young adults with full natural dentition.
Materials and Methods
162 ( K-78/M-84) patients with full natural teeth aged 18-21 and correct occlusal conditions.
Measurement of overbite and overjet in clinical conditions and assessment of muscle activity (EMG) of selected muscles of the masticatory system (masseters, temporal muscles, sternocleidomastoid muscles, anterior bellies of digastric muscles). Muscle activity was assessed in central occlusion and during lateral movements of the mandible. The obtained research results were subjected to statistical analyses using Statistica 13.
Results
Average value of overbite: 3.08±1.83mm (n-162), average value of overjet 2.18±1.47mm (n-162). A significant relationship was found between the activity of the masseter and digastric muscles in central occlusion and the size of the overbite: (MM-R r=0.19 p<= 0.02;MM-L r=0.17 p<= 0.03;DA-R r=0.21 p <= 0.01;DA-L r=0.23 p<=0.004). The activity of the temporal muscles in lateral movements of the mandible significantly correlated with the overbite: (TA-R/RM r=0.20 p<=0.012;TA-L/RM r=0.28 p<= 0002;TA-R/LM r=0.19 p<= 0.02;TA-L/LM r=0.24, p<= 0.002).
A significant correlation was found between the activity of the temporal muscles and the overjet during lateral movements of the mandible: (TA-R/RM r=0.23 p=<0.004;TA-L/RM r=0.27 p<=0.001; TA-R/LM r=0.18 p<=0.024;TA-L/LM r=0.20 p<=0.01;DA-R/LM r=0.20 p<=0.01;DA-L/LM r=0.18 p<=0.02).
Conclusions
The size of the overbite significantly affects the activity of the masseter and digastric muscles in central occlusion. The size of the overjet has a significant relationship with the activity of the temporal muscles and digastric muscles