Changes in Dental Caries Among 9-Year-Old Schoolchildren After One Year

Objectives: The purpose of this study was to assess the changes in dental caries among 9-year-old schoolchildren after one-year follow-up and to analyze risk factors regarding the changes. Methods: 149 schoolchildren aged 9 years old were selected and distributed into two groups - group 1 (n=52): “caries free” and group 2 (n=97): “high caries (with at least 3 caries lesions)”. Dental caries was recorded at baseline and reevaluated after one year by calibrated examiners using WHO Criteria 1997. Plaque pH, salivary viscosity, non-stimulated salivary pH, stimulated salivary flow and salivary buffering capacity which were measured by Plaque-check+pH^® and Saliva-check Buffer^®Kit (GC Corporation). The amount of Streptococcus mutans and Lactobacilli was assessed using CRT^®Bacteria Kit (IvoclarVivadent). Oral hygiene status was evaluated according to OHI-S index. Socioeconomic and behavioral characteristics were also included in a questionnaire. All these caries- related factors were evaluated at baseline. Logistic regression model was applied. Results: After one year, DMFS increased by 1.15 ±1.66 in group 1 and 1.64± 1.46 in group 2; there was an increase of 1-2 caries surfaces in 25% subjects in group 1 and 53.6% in group 2 with a significant difference between the two groups (p<0.001). Among caries related factors measured at baseline, “caries  experience in permanent teeth in  the past” (OR 9.52; p<0.001) and “poor salivary buffering capability” (OR 2.74; p<0.05) were significantly correlated with the increase of at least 1 DMFS. “Caries experience in permanent teeth in the past” (OR 11.6; p<0.001) and “parents’ low income” (OR 3.78; p<0.05) were significantly correlated with the increase of at least 2 DMFS. Conclusion: DMFS increased in both groups after one year. “Caries experience in permanent teeth in the past” was the risk factor most significantly associated with the increase of at least 1 and 2 DMFS after one year.