Objective: Gingivitis and poor oral hygiene status are the most prevalent oral diseases among primary school students. Poor oral hygiene status, gingivitis and socio-demographic determinants have been shown to be associated with periodontal diseases. There is limited information on the gingivitis and oral hygiene status among Iranian children. In the present study, the status of gingivitis, oral hygiene status, and their association with socio-demographic determinants among schoolchildren aged 7-12 years old in Hamadan were investigated.

Methods: In this cross-sectional study, 988 primary school students aged 7-12 years old were selected. The oral hygiene status was measured through Simplified Oral Hygiene Index (OHI-S) and Community Periodontal Index (CPI) was used to evaluate gingival bleeding and calculus. CPI was measured using a standardized protocol to investigate gum bleeding and calculus. The oral hygiene was classified as good, fair or poor based on calculus and debris measurements. Age, gender, educational level, occupation and residence district of parents, dental pain experience in the last year and whether parents supervised their children while brushing were assessed by the questionnaires. The collected data were analyzed using descriptive statistics and logistic regression analysis.

Results: The oral hygiene status was good in 644 students (65.20%), fair in 341 (34.50%) and poor in three (0.30%). Moreover, the results of CPI depicted that 639 students (64.07%) had healthy periodontium, 320 (32.40%) had periodontal bleeding and 29 (2.9%) were with calculus. Higher percentage of the boys in the age group of 12 years old had periodontal bleeding and fewer good oral hygiene. The results of CPI and OHI-S scores depicted that more than half of the primary school students had healthy gums and periodontium (64.1%) and good oral hygiene status (65.2%). There were significant statistical associations between age and residence district with calculus measured by the CPI, also between gender, age, residence district, and mother's occupation with the gingival bleeding measured by the CPI. Furthermore, age and mother's occupation were significantly associated with OHI-S index.

Conclusions: In general, the periodontal health status is poorer in students attending suburban schools compared to those in urban schools in Hamadan. Since there are significant associations between gender, school districts and mother's occupation with oral hygiene index among schoolchildren in primary schools, considering them in schools' oral health program design might be useful.