Table 4.

Ultrasonography examination of masticatory muscles in upright and supine positions.

Unit: mm			TMD_nonbruxers (n = 66) Mean ± SD	TMD_bruxers (n = 30) Mean ± SD	p-value (nonbruxers vs. bruxers)	Male (n = 29)	Female (n = 67)	p-value (male vs. female)
						Mean ± SD	Mean ± SD
Upright position	Masseter m.	Resting	10.44 ± 2.77	12.73 ± 3.03	< 0.001***	12.46 ± 3.14	10.59 ± 2.83	0.008**
		Clenching	13.48 ± 3.41	15.26 ± 3.39	0.021*	14.98 ± 3.00	13.69 ± 3.59	0.074
	Temporal m.	Resting	7.59 ± 1.90	8.05 ± 2.01	0.284	7.97 ± 1.75	7.76 ± 2.45	0.688
		Clenching	7.89 ± 1.96	8.61 ± 2.12	0.114	8.49 ± 1.83	8.16 ± 2.61	0.540
Supine position	Masseter m.	Resting	10.93 ± 2.55	11.92 ± 1.97	0.043*	12.43 ± 2.74	10.72 ± 2.08	0.004**
		Clenching	12.97 ± 3.05	14.62 ± 2.90	0.014*	15.23 ± 3.35	12.73 ± 2.66	< 0.001***
	Temporal m.	Resting	7.74 ± 1.85	8.43 ± 2.27	0.119	8.44 ± 2.94	8.11 ± 1.58	0.578
		Clenching	8.04 ± 1.86	8.61 ± 1.96	0.179	8.53 ± 2.37	8.39 ± 1.74	0.765

The results were obtained using t-tests. m, masseter muscle. Statistical significance was set at p < 0.05. *p < 0.05, **p < 0.01, ***p < 0.001. The significant values are indicated in bold font.