From: Prevalence of gingivitis and calculus in 12-year-old Puerto Ricans: a cross-sectional study
 |  |  | Total Calculus (yes/no) | Supragingival Calculus | Subgingival Calculusa | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Strata | N | Wt N | % | 95% CI | p-value2b | % | 95% CI | p-value2b | % | 95% CI | p-value2b |
Gender | |||||||||||
 Female | 841 | 814 | 57.31 | (51.10–63.51) | 0.005 | 52.37 | (46.27–58.47) | 0.001 | 18.34 | (13.35–23.32) | 0.34 |
 Male | 745 | 773 | 66.28 | (60.95–71.60) | 62.06 | (56.59–67.65) | 21.30 | (16.72–25.88) | |||
School Type | |||||||||||
 Rural- public | 597 | 612 | 52.68 | (45.93–59.44) | 0.63 | 46.07 | (39.13–53.01) | 0.47 | 20.80 | (15.42–26.18) | 0.02 |
 Urban- public | 628 | 722 | 67.39 | (59.49–75.29) | 0.55 | 64.18 | (56.57–71.80) | 0.47 | 20.25 | (13.73–26.76) | 0.23 |
 Private | 361 | 253 | 66.60 | (57.23–75.98) | – | 63.49 | (55.08–71.89) | – | 15.98 | (7.94–24.01) | – |