Table 2 Characteristics of the Dutch population from the Dutch National Oral Health Survey 1995–2013
| Â | 1995 | 2002 | 2007 | 2013 | P valueb |
|---|---|---|---|---|---|
(n = 917) | (n = 795) | (n = 669) | (n = 702) | ||
Age year, mean (SD) | 38.1 (8.1) | 40.7 (8.0) | 41.1 (8.5) | 40.2 (8.6) | .000 |
Age group, n (%) | Â | Â | Â | Â | .000 |
 25–34 y | 353 (38.5) | 211 (26.5) | 177 (26.5) | 217 (30.9) |  |
 35–44 y | 317 (34.6) | 310 (39.0) | 227 (33.9) | 235 (33.5) |  |
 45–54 y | 247 (26.9) | 274 (34.5) | 265 (39.6) | 250 (35.6) |  |
Gender, n (%) | Â | Â | Â | Â | .000 |
 Male | 450 (49.1) | 318 (40.0) | 304 (45.4) | 284 (40.5) |  |
 Female | 467 (50.9) | 477 (60.0) | 365 (54.6) | 418 (59.5) |  |
Ethnicity, n (%) a | Â | Â | Â | Â | .000 |
 Native | 831 (91.1) | 639 (80.8) | 576 (86.5) | 636 (90.6) |  |
 Non-native | 81 (8.9) | 152 (19.2) | 90 (13.5) | 66 (9.4) |  |
Socioeconomic status, n (%) | Â | Â | Â | Â | .000 |
 Low | 579 (63.1) | 601 (75.6) | 309 (46.2) | 264 (37.6) |  |
 High | 338 (36.9) | 194 (24.4) | 360 (53.8) | 438 (62.4) |  |
Time since the last dental visit, n (%)a | Â | Â | Â | Â | .009 |
 More than 1 year | 57 (6.2) | 71 (8.9) | 73 (10.9) | 63 (9.0) |  |
 Less than 1 year | 859 (93.8) | 723 (91.1) | 595 (89.1) | 638 (91.0) |  |
Toothbrushing frequency, n (%)a | Â | Â | Â | Â | .000 |
  <  Once per day | 254 (27.7) | 218 (27.4) | 122 (18.3) | 182 (26.0) |  |
  >  Twice per day | 663 (72.3) | 577 (72.6) | 545 (81.7) | 517 (74.0) |  |
Floss usage, n (%) a | Â | Â | Â | Â | .000 |
 Non-daily | 821 (89.5) | 717 (90.2) | 561 (84.4) | 533 (75.9) |  |
 Daily | 96 (10.5) | 78 (9.8v | 104 (15.6) | 169 (24.1) |  |
Tooth pick usage, n (%)a | Â | Â | Â | Â | .000 |
 Non-daily | 768 (83.8) | 676 (85.0) | 541 (81.5) | 486 (69.2) |  |
 Daily | 149 (16.2) | 119 (15.0) | 123 (18.5) | 216 (30.8) |  |
Number of teeth present, mean (SD) | 24.1 (5.3) | 24.0 (5.4) | 25.3 (4.1) | 26.4 (3.1) | .000 |