The effect of mouth breathing on dentofacial morphology of growing child

Backround: The oral mode of respiration cause postural adaptations of structures in the head and neck region producing the effect on the positional relationship of the jaws. Aim: The aim of this study is to verify the skeletal relationship of mouth and nose breathing child. Study design: A cross sectional study was performed to assess the association of changed mode of respiration with dentofacial growth. Materials and Methods : One hundred children among which 54 were mouth breathers and 46 were nasal breathers of 6-12 years of age were submitted to clinical examination and cephalometric radiographical analysis. Statistical analysis : Chi-square test for proportions and independent sample′s ′t′test for parametric data is used. Result: The mean values of N-Me (P<0.001) ANS-Me (P<0.001) and SN-GoGn (P<0.001) for mouth breathers is significantly higher. ArGo-GoMe (P=0.003) and (P<0.011) for 6-9 and 9-12 years age group, respectively, were significantly low in nasal breathers group. Conclusions: Changed mode of respiration was associated with increased facial height, mandibular plane angle and gonial angle

Plateau 'pop-up' in the great 1897 Assam earthquake.

The great Assam earthquake of 12 June 1897 reduced to rubble all masonry buildings within a region of northeastern India roughly the size of England, and was felt over an area exceeding that of the great 1755 Lisbon earthquake. Hitherto it was believed that rupture occurred on a north-dipping Himalayan thrust fault propagating south of Bhutan. But here we show that the northern edge of the Shillong plateau rose violently by at least 11 m during the Assam earthquake, and that this was due to the rupture of a buried reverse fault approximately 110 km in length and dipping steeply away from the Himalaya. The stress drop implied by the rupture geometry and the prodigious fault slip of 18 +/- 7 m explains epicentral accelerations observed to exceed 1g vertically and surface velocities exceeding 3 m s-1 (ref. 1). This quantitative observation of active deformation of a 'pop-up' structure confirms that faults bounding such structures can penetrate the whole crust. Plateau uplift in the past 2-5 million years has caused the Indian plate to contract locally by 4 +/- 2 mm yr-1, reducing seismic risk in Bhutan but increasing the risk in northern Bangladesh