Prevalence of interproximal periodontal intrabony defects in an adult population in Sweden. A radiographic study.

The aim of this study was to determine the prevalence and localization of interproximal periodontal intrabony defects (IPIDs) in the total adult population of a Swedish county. On each interproximal tooth surface (third molars excluded) in 733 randomly selected dentate individuals aged 20 years and over, one examiner recorded from x5-magnified periapical radiographs, the presence or absence of IPID with a width and depth of at least 5 and 10 mm, respectively, representing 1 and 2 mm unmagnified. Intra-examiner reproducibility determined from double recordings was substantial (kappa = 0.66). Recordings of IPID were compared with those performed by 24 specialist periodontists using their own diagnostic criteria. IPIDs were recorded in 32% of the 733 examined individuals; the number of defects per individual ranged from 1 to 15. The prevalence of IPID increased with increasing age and IPID occurred more frequently in men than in women. IPID was observed more frequently on mesial than on distal tooth surfaces, whereas there was no difference between maxillary and mandibular tooth surfaces. Symmetrical localizations of IPID in relation to the sagittal plane were observed.