The aim of this study was to evaluate if the improper way of breathing by mouth coexisting with malocclusions may have an impact on the activity of respiratory centers in children in adolescence.
Methods There were 110 children aged 10–12 years under examination. The way of breathing (nasal and oral) and the presence and degree of malocclusions were estimated. Respiratory regulation was evaluated by synchronic measurements of the respiratory pattern (according to Milic-Emili) and occlusion pressure was measured using computerized spirometer Lungtest -Poland.
Results From 110 children two groups with opposing results in the range of analyzed feature were selected: 34 children with oral way of breathing and advanced malocclusions (group I), and 25 -free of malocclusion and with nasal way of breathing (group II-controls). Tidal volume (TV), breath frequency (BF), minute ventilation (MV), the mean times of inspiration (Tin) and total time of inspiration-expiration cycle (Ttot) were similar in both groups. The timing component of respiratory pattern (Tin/Ttot) was 0,447+0.04 in I group and 0.456+ 0,456 in group II (ns), whereas the values of occlusion pressure (P0,1) and driving component of respiratory pattern (VT/Tin) were significantly higher (p<0.05) in group I in comparison to the controls (P0,1:5.76+ 3.11 vs 5.06 +1.75 cmH2O and VT/Tin: 0.562+0.25 vs 0.526+0.17).
Conclusions In the group of children with oral respiration and malocclusions the neuromuscular respiratory drive and occlusion pressure, which is independent of pulmonary mechanics, were elevated in comparison to the controls but parasympathetic control of breathing cycle was similar in both examined groups.