A DIGITAL SUBTRACTION RADIOGRAPHY INVESTIGATION OF UPPER FIRST MOLAR PROXIMAL BONE-DENSITY CHANGES IN ADOLESCENTS

The aim of this in vivo study was to investigate the ability of digita l subtraction radiography to monitor changes in proximal bone density, adjacent to the upper first molars, in a group of adolescents using t he Digora direct digital radiographic system to acquire images. For 57 adolescents, assessments of changes in probing attachment level at th e mesio- and disto-buccal surfaces of both upper first molars and prox imal crestal bone density using digital subtraction radiography were m ade. At the conclusion of this 21-month study attachment loss was iden tified in 34 (17%) of the 204 sites analysed. For sites with attachmen t loss a mean decrease in bone density equivalent to 5.51 mm(3) alumin ium (Al) was found compared to 2.96 mm(3) Al for those without (p< 0.0 01). For the 17 subjects with attachment loss a mean equivalent to 4.6 6 mm(3) Al was lost from the crestal bone compared with 2.56 mm(3) Al for the 40 subjects without attachment loss (p<0.01). The correlation between attachment loss and bone density changes was poor for both sit es (r=0.13, p = 0.067) and mean scores for subjects (r=0.24, p=0.069). A visual qualitative assessment of bone density change found that 70. 6% of sites with attachment loss compared to 62.4% of those without ha d a decrease in crestal bone density. This study suggests that it is p ossible to monitor bone density changes in adolescents, with a develop ing dentition, using digital subtraction radiography. Further, it is s uggested that conventional probing assessments of attachment level may underestimate the level of destructive periodontal disease in this ag e group.