The study, published in Frontiers in Oral Health, recruited women attending routine prenatal appointments at public health centers in Arrecife, the capital of the volcanic island of Lanzarote in the Canary Islands. Participants ranged from 16 to 44 years old, with a mean age of 29.81 years, and were between 6 and 41 weeks of gestation. Each woman completed a structured face-to-face interview covering sociodemographic characteristics, pregnancy history, anthropometric measurements, oral hygiene habits, and smoking, and then answered 13 items drawn from the Maternal Oral Health Knowledge, Attitudes and Practices Questionnaire known as CAPSOM.

Clinical examinations were performed by a single trained and calibrated examiner using a dental mirror and a World Health Organization periodontal probe. Three indicators were recorded: the Silness and Löe Plaque Index for plaque accumulation, the Löe and Silness Gingival Index for gum inflammation, and the Tricolor Index, a measure of biofilm maturity obtained with a disclosing gel that distinguishes recently formed plaque from mature and acid-producing bacterial layers. Reliability was excellent, with intraclass correlation coefficients ranging from 0.88 to 0.96 across duplicate examinations.

The behavioral picture looked encouraging at first glance. On average, women reported brushing their teeth 2.29 times per day, 96.6 percent brushed at least once daily, and 78.5 percent reported brushing at night. Only 3.4 percent said they never brushed. Yet clinical measurements revealed meaningful variation: the mean Plaque Index was 0.60, the mean Gingival Index was 0.44, and the mean Tricolor Index was 0.92, indicating that plaque and inflammation persisted despite generally good self-reported habits.

To disentangle the effects of knowledge from behavior, the researchers fitted hierarchical multiple linear regression models in three blocks. The first block included maternal age, gestational week, number of pregnancies, educational level, and occupational socioeconomic status. The second added toothbrushing frequency and cigarette consumption, and the third added the CAPSOM-derived composite knowledge, attitudes, and practices (KAP) score. The final models explained 60.7 percent of the variance in Plaque Index, 53.1 percent in Gingival Index, and 69.2 percent in Tricolor Index, but the contributions of each block told very different stories.

Toothbrushing frequency emerged as the strongest and most consistent predictor. Each additional daily brushing session was independently associated with lower values on all three clinical outcomes, with standardized coefficients ranging from −0.435 to −0.518, all statistically significant. In contrast, the composite KAP score added only 0.6 percent of explained variance for Plaque Index and 2.1 percent for Tricolor Index, and failed to improve the Gingival Index model at all. A ten-point difference in the composite score corresponded to roughly 0.06 units of Plaque Index and 0.15 units of Tricolor Index, a modest clinical effect.

Sensitivity analyses sharpened this interpretation. When the behavioral variables were removed from the models, the 13-item composite score appeared much stronger, accounting for an additional 7.5 percent of Plaque Index variance and 11.3 percent of Tricolor Index variance. But when the researchers replaced the full composite with a six-item nonbehavioral version, stripping out items that overlapped with self-reported hygiene practices, the association survived only for the Tricolor Index. This suggests that part of the apparent link between knowledge and clinical outcomes may simply reflect the behavioral content embedded in the questionnaire itself.

Night-time toothbrushing told perhaps the most striking story. Women who did not brush before bed had dramatically worse clinical profiles: a mean Plaque Index of 1.058 versus 0.471 among those who did, a Gingival Index of 0.828 versus 0.338, and a Tricolor Index of 1.476 versus 0.768. The effect sizes were large, with Hedges’ g values of 1.489 to 1.859. Even after adjusting for overall brushing frequency, smoking, education, socioeconomic status, gestational week, and the composite KAP score, night-time brushing remained independently associated with lower values on all three outcomes, suggesting that the timing of brushing carries information beyond simple daily counts.

Other factors left their mark on the clinical picture. Gestational week and cigarette consumption were both positively associated with Gingival Index, consistent with the idea that hormonal and immunological changes during pregnancy heighten susceptibility to gum inflammation, while smoking independently worsened biofilm maturity. Educational level showed a significant overall association with all three outcomes even after adjustment, whereas occupational socioeconomic status did not reach statistical significance in the final models. Women with lower educational attainment consistently showed worse plaque, inflammation, and biofilm scores than those with second-cycle secondary education.

The authors caution that the cross-sectional design cannot establish causality, that the clinic-based sample may overrepresent health-conscious women, and that self-reported brushing frequency says nothing about technique, duration, or effectiveness. Still, the message for prenatal care is clear and actionable. Educational interventions that stop at information delivery may have limited impact if they are not paired with practical behavioral counseling, including adequate brushing frequency, an emphasis on the crucial night-time session, proper technique, and facilitated access to preventive dental care. As the researchers conclude, oral hygiene behaviors appear to have a stronger association with clinical oral health during pregnancy than knowledge and attitudes alone, a finding that should reshape how midwives, dentists, and public health programs approach maternal oral health promotion.

Subject of Research: Association between oral health knowledge, attitudes, practices, toothbrushing behaviors, and clinical oral health indicators in pregnant women

Article Title: Oral health knowledge, attitudes, practices and behavioral factors associated with clinical oral health indicators in pregnant women: a cross-sectional study in Spain

Article References: Suárez-Sánchez, F. M., Prieto-Regueiro, B., Ticona-Flores, J. M., Tabone, M., & Diéguez-Pérez, M. (2026). Oral health knowledge, attitudes, practices and behavioral factors associated with clinical oral health indicators in pregnant women: a cross-sectional study in Spain. Frontiers in Oral Health, 7, Article 1928373. https://doi.org/10.3389/froh.2026.1928373

Image Credits: AI Generated

DOI: 10.3389/froh.2026.1928373

Keywords: pregnancy, oral health, toothbrushing, plaque index, gingival inflammation, biofilm maturity, CAPSOM questionnaire, prenatal care, cross-sectional study, Spain, health education, maternal health