The difference of stress distribution of maxillary expansion using rapid maxillary expander (RME) and maxillary skeletal expander (MSE)—a finite element analysis

Progress in Orthodontics

Table 2 Independent t test of the nodes on various displacement of expansion using RME and MSE (region of interest: upper first molar)

Expansion method	Stress	Displacement	N	Mean	SD	CI 95%		p
Expansion method	Stress	Displacement	N	Mean		Lower	Upper	p
RME	Von Ms	0.5 mm	225	10.86904	1.181594	1.03669	1.38926	0.00^*
MSE	Von Ms		225	9.65606	0.641251	1.03669	1.38926
RME	Von Ms	1 mm	225	1.49844	0.015366	− 5.23739	− 5.21068	0.00^*
MSE	Von Ms		225	6.72249	0.100525	− 5.23739	− 5.21068
RME	Von Ms	1.5 mm	225	5.74535	0.128029	0.04932	0.0872	0.00^*
MSE	Von Ms		225	5.67708	0.067008	0.04932	0.0872
RME	MaxPs	0.5 mm	225	4.31042	0.257529	− 4.54820	− 4.39736	0.00^*
MSE	MaxPs		225	8.78321	0.514199	− 4.54820	− 4.39736
RME	MaxPs	1 mm	225	1.80901	0.044066	− 0.76577	− 0.75060	0.03^*
MSE	MaxPs		225	2.56719	0.037552	− 0.76577	− 0.75060
RME	MaxPS	1.5 mm	225	11.36281	0.592480	− 15.3542	− 14.6147	0.00^*
MSE	MaxPS		225	26.34729	2.752635	− 15.3542	− 14.6147
RME	MinPS	0.5 mm	225	− 0.09651	0.012786	0.14908	0.15695	0.00^*
MSE	MinPS		225	− 0.24953	0.027169	0.14908	0.15695
RME	MinPS	1 mm	225	− 0.72524	0.014304	1.00171	1.01227	0.00^*
MSE	MinPS		225	− 1.73224	0.037582	1.00171	1.01227
RME	MinPS	1.5 mm	225	− 0.45977	0.029023	0.19041	0.2124	0.00^*
MSE	MinPS		225	− 0.66117	0.078496	0.19041	0.2124

Independent t test, statistical significance was determined at the p < 0.05 level
*Significant at p < 0.05 level