Comparison between standardized periapical and bitewing radiographs in assessing alveolar bone loss

Readability and alveolar bone level were compared in 455 sets of standardized radiographs each consisting of four periapical (PA) and two bitewing (BW) films. BW radiographs showed significantly higher proportions of unreadable sites in the canines and the mesial surface of first premolars (P less than 0.0001), while PA radiographs exhibited significantly higher proportions of unreadable sites in the distal surface of second molars (P less than 0.0001). Alveolar bone level was assessable in a total of 10016 sites, and the comparison showed identical readings in 82% of the sites. In the maxilla, a significantly higher proportion of sites exhibited larger bone loss measurements (P less than 0.0001) and more sites with significantly higher mean values (P less than 0.005) in BW than in PA films. Mandibular sites showed the opposite trend. The majority of the sites revealed a Pearson's correlation coefficient (r) ranging between 0.60 and 0.82. No significant difference between mean bone loss measurements in the two types of radiographs for all the sites was found. It was concluded that the two radiographic techniques may be used interchangeably in epidemiologic studies.