Table 5.

Comparison between 1) GERD patients and all controls; 2) younger GERD patients and younger controls; 3) older GERD patients and older controls

Variable	GERD	All	*P value	Younger GERD	Younger	*P value
	Patients	Controls		Patients	Controls
	n = 105	n = 50		n = 13	n = 25
Salivary flow volume; Saxon test (g/2 min.)	1.7 ± 1.5	3.6 ± 1.5	< 0.001*	1.8 ± 1.3	4.2 ± 1.4	< 0.001*
Swallowing function; RSST
Swallowing frequency (times/30 s)	4.0 ± 2.1	6.9 ± 2.5	< 0.001*	4.3 ± 1.3	8.1 ± 2.4	< 0.001*
Time to first swallow (s)	4.9 ± 4.8	2.1 ± 1.1	< 0.001*	4.7 ± 3.4	1.6 ± 1.2	< 0.001*
Teeth; DMF indices (%)	70.2 ± 23.7	47.9 ± 37.6	< 0.001*	50.5 ± 23.9	14.9 ± 13.1	< 0.001*
Soft tissues; gingivitis
PMA gingival indexes	1.58 ± 1.98	0.2 ± 0.4	< 0.001*	1.20 ± 1.80	0.04 ± 0.20	0.428
OHI-S	1.41 ± 1.45	0.3 ± 0.6	< 0.001*	1.10 ± 1.30	0.08 ± 0.28	0.226
Variable	Older GERD	Older	*P value
	Patients	Controls
	n = 92
Salivary flow volume; Saxon test (g/2 min.)	1.7 ± 1.6	3.0 ± 1.3	< 0.001*
Swallowing function; RSST
Swallowing frequency (times/30 s)	4.0 ± 2.2	5.7 ± 2.1	< 0.001*
Time to first swallow (s)	4.9 ± 5.0	2.5 ± 0.9	0.090
Teeth; DMF indices (%)	73 ± 22.4	80.8 ± 21.1	0.101
Soft tissues; gingivitis
PMA gingival indexes	1.6 ± 2.0	0.36 ± 0.49	< 0.001*
OHI-S	1.5 ± 1.5	0.56 ± 0.77	< 0.001*

GERD Gastroesophageal reflux disease, RSST Repetitive saliva swallowing test, DMF indices Decayed, missing, and filled indices, PMA gingival indexes Papillary, marginal, and attached gingival indexes, OHI-S Simplified oral hygiene indices

*P values of Wilcoxon rank-sum test were judged as significant by P < 0.05