Flossing is Associated With Disease Prevalence and 10-year Tooth Loss

Objectives: Recent removal of flossing recommendation from the Dietary Guidelines for Americans issued by the federal government reports have questioned the importance of flossing. The purpose of this study was to estimate the prevalence of disease and 10-year tooth loss among flossers and non-flossers.
Methods: Three population studies using random sampling methods were analyzed: NHANES-2009-14 (n=10,513), Dental Atherosclerosis Risk In Communities (DARIC) (n=6,653), and Piedmont 65+dental study (PDS) (n=419). All studies used standardized examiners. Outcome measurements used were extent of interproximal clinical attachment levels (iCAL)≥3mm and interproximal probing depth (iPD)≥4mm. Tooth loss was available by a 10-year follow-up questionnaire in DARIC and 5-year tooth loss was calculated based on exam for PDS. Demographics, flossing (numbers of times/week) and brushing (number of times/day) data were collected via questionnaire. General linear models (SAS-proc GLM) and hazard ratios (PROC-GENMOD) were used. All analysis presented include adjustment for age, race, gender, diabetes, smoking and education.
Results: DARIC flossers had lower mean extent of sites with iCAL≥3mm compared to non-flossers [22.0% (SE=0.33) vs 26.7% (0.45) sites, p≤0.0001]. NHANES findings showed similar pattern with flossers having iCAL≥3mm [20.0% (0.28)] compared to non-flossers [29.5% (0.42) sites, p≤0.0001]. Stratifying by number of times brushed/day, we found that DARIC participants who flossed ≥1X/week and brushed 0-2X/day showed lower levels of clinical measurements compared to non-flossers (iCAL≥3mm and iPD≥4mm). The relative risk for 10-year tooth loss in DARIC showed that non-flossers had a 1.25 (1.03-1.52) excess risk for loosing ≥3 teeth. Similar data in the PDS for 5-year risk of tooth loss showed that non-flossers had a 3.23 (1.82-5.74) excess risk of losing ≥3 teeth.
Conclusions: Flossing was associated with lower extent of iCAL and iPD even in the presence of brushing 1-2 times/day. Flossing was associated with lower risk of tooth loss over 5 years and 10-years.