Table 3.

Correlations of biological and psychological factors among different classifications of temporomandibular disorders (TMD)

	Pain-related TMD (n = 37)		Intra-articular TMD (n = 160)		Combined TMD (n = 42)
	r	p value	r	p value	r	p value
Biological factor
Age	0.013	0.711	0.020	0.585	0.062	0.091
Gender	0.008	0.832	0.097	0.008	0.089	0.014
Sleep bruxism	0.078	0.033	0.075	0.039	0.126	0.001
Awake bruxism	0.039	0.280	0.075	0.040	0.031	0.390
Empty chewing	0.031	0.394	0.112	0.002	0.162	< 0.001
Unilateral chewing	0.074	0.042	0.118	0.001	0.164	< 0.001
Chewing gum	0.033	0.371	0.037	0.310	0.064	0.081
Static occlusion
Angle’s malocclusion	0.030	0.567	0.066	0.078	0.051	0.764
Anterior teeth overbite	0.099	0.006	0.096	0.008	0.071	0.050
Anterior teeth overjet	0.060	0.097	0.078	0.031	0.027	0.451
Posterior teeth crossbite	0.020	0.580	-0.066	0.070	0.015	0.674
Posterior scissor bite	0.013	0.720	0.003	0.926	0.092	0.051
Psychological factor
Depression	0.116	0.001	0.119	0.001	0.148	< 0.001
Anxiety	0.134	< 0.001	0.230	< 0.001	0.148	< 0.001
Sleep disturbance	0.026	0.477	0.119	0.001	0.114	0.002