Relationships between bitewing and periapical radiographs in assessing crestal alveolar bone levels

Bitewing (BW) and periapical (PA) radiographic techniques are used in clinical and epidemiologic studies to assess crestal alveolar bone levels. Since there appeared to be no basis for choosing one technique over the other, the present study investigated relationships between these techniques by assessing alveolar crest location at the same site. BW and PA radiographs were available from posterior quadrants of 210 subjects. Individual radiographs were projected at a magnification x 5.9 using a Leitz Prado-Universal projector. The distance from the cemento-enamel junction to the alveolar crest (CEJ-CR) was measured for each proximal surface from the distal of the cuspid to the distal of the second molar. Data were arranged according to the proximal surface examined, and BW and PA measurements were compared using paired t tests. In addition, the degree of congruence of the two sets (BW/PA) of CEJ-CR measurements was evaluated through computation of the Pearson Correlation. The data showed significant differences between mean BW and PA measurements for 50% of the tooth surfaces, and this trend was consistent through maxillary and mandibular quadrants, and mesial and distal surfaces. In situations of a significant difference, the BW measurement was greater than the PA 94% of the time. The correlations between the two types of measurements showed low reliability. It was concluded that BW and PA techniques provided significantly different values in assessing crestal alveolar bone levels, and data generated by these techniques should not be used interchangeably on an individual or group basis.