Periodontitis and dental caries occur together.

SUBJECTS: This nationally representative sample of the Finnish population consisted of 5255 individuals aged 30 years and older. Data were collected between 2000 and 2001. All participants had natural teeth and received a complete oral examination consistent with World Health Organization (WHO) recommendations. KEY RISK/STUDY FACTOR: Periodontitis in individuals was measured in 4 ways:(1) Periodontitis prevalence-at least 1 tooth with periodontal pocket depth of 4 mm or greater; (2) severe periodontitis prevalence-at least 1 tooth with periodontal pocket depth of 6 mm or greater; (3) mean periodontal pocket depth per person; and (4) percentage of teeth per person with periodontal pocket depth of 4 mm or greater or 6 mm or greater. MAIN OUTCOME MEASURE: Decayed teeth (DT) were defined as the presence of untreated caries reaching the dentin. DT in individuals was measured in 3 ways: (1) DT prevalence-at least 1 tooth with untreated caries reaching the dentin; (2) mean number of DT per individual; and (3) percentage of DT per person. MAIN
RESULTS: Sixty-four percent of persons had periodontal disease, 21% had severe periodontal disease, and 29% had dental caries. Persons with periodontal disease were more likely to have dental caries (33%) compared with those without periodontal disease (23%). Among those with severe periodontal disease, 44% had dental caries. Accordingly, in caries-free study participants, 16% had severe periodontal disease, whereas among persons with dental caries, 31% had severe periodontal disease. The mean number of teeth with dental caries or periodontal disease per person was greater when the mean number of teeth with the other disease was also greater.
CONCLUSIONS: Periodontal disease was more common when dental caries was present. The relation was stronger when periodontal disease was severe.