title: Comparison of two preventive interventions on dental caries among children in Democratic People's Republic of Korea.
abstract: OBJECTIVE
  The aim was to compare the change in dental caries status in two different intervention groups of the Children's Oral Health Promotion Programme (COHPP).
  
  
  METHODS
  A longitudinal study among 500 children who had participated into the COHPP for 6 years was conducted in Pyongyang, Democratic People's Republic of Korea (DPRK). Children in Group I received intensified school-based intervention and were clinically examined at the age of 7 years in 2007 (n = 250), 10 years in 2010 (n = 250) and 13 years in 2013 (n = 242). Children in Group II (n = 250) joined the programme at the age of 4 years in kindergarten in 2007, were provided with early preschool-based intervention and were clinically examined at the age of 7 years in 2010 and 10 years in 2013.
  
  
  RESULTS
  Both the prevalence and the mean number of dt + DT decreased significantly in both groups during the follow-up. This was due to decrease in the number of dt, whereas the number of DT remained relatively constant. Poisson regression showed that the association between the group status and the change in the number of dt + DT was statistically significant when adjusted for gender but disappeared when the school was included in the analysis.
  
  
  CONCLUSIONS
  The decrease in dental caries may be partly due to the exfoliation of deciduous teeth and dental treatment received. However, the study gave some reference emphasizing the early starting of the prevention.
authors.affiliation: Institute of Dentistry, University of Eastern Finland, Kuopio, Finland. pirkkoliisa.tarvonen@gmail.com.|Oral Health Care, Social Services and Health Care, Department of Social Services and Health Care, Helsinki, Finland. pirkkoliisa.tarvonen@gmail.com.
authors.forename: P-L
authors.initials: PL
authors.lastname: Tarvonen
authors.affiliation: Institute of Dentistry, University of Eastern Finland, Kuopio, Finland.|Oral and Maxillofacial Department, Kuopio University Hospital, Kuopio, Finland.|Research Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, Oulu, Finland.|Department of Oral and Maxillofacial Surgery, Medical Research Centre Oulu, Oulu University Hospital, Oulu, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Sipilä
authors.affiliation: Korea Education Fund, Pyongyang city, Democratic People's Republic of Korea.
authors.forename: G S
authors.initials: GS
authors.lastname: Yang
authors.affiliation: Dental Faculty, Pyongyang Medical College, Kim Il Sung University, Pyongyang city, Democratic People's Republic of Korea.
authors.forename: J K
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: M-L
authors.initials: ML
authors.lastname: Lamidi
authors.affiliation: Institute of Dentistry, University of Eastern Finland, Kuopio, Finland.|Oral and Maxillofacial Department, Kuopio University Hospital, Kuopio, Finland.
authors.forename: A L
authors.initials: AL
authors.lastname: Suominen
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D056911:Democratic People's Republic of Korea / Q000453:epidemiology; D003731:Dental Caries / Q000453:epidemiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D012572:School Health Services
keywords: dental caries; oral health; school-based prevention programmes