[Evaluation with different measuring methods for the alveolar bone change of ridge preservation in molar sites]

To investigate the changes of the vertical height and width of the alveolar bone six months after the alveolar ridge preservation in periodontal compromised molar sites of severe alveolar bone defects with clinical direct measurement, parallel periapical radiographs, and cone-beam computed tomography (CBCT), and to analyze the effect of the three different methods of measurement.

In this study, 20 subjects requiring tooth extraction on account of periodontal disease with a total of 23 extracted molars were enrolled. Extractions were performed atraumatically and patients were received alveolar ridge preservation procedure with Bio-Oss and Bio-Gide. Clinical direct measurements were taken after tooth extraction and during the implant surgery 6 months later, CBCT scans and parallel periapical radiographs were taken immediately after ridge preservation and 6 months later. The changes of alveolar ridge width and vertical height after six months were measured and analyzed through the above-mentioned three methods and the similarities and differences of the measured effect were compared.

There were no significant difference of alveolar vertical height in the center of the extraction sites, the center of distal aspect, and distobuccal aspect between the clinical direct measurements and the CBCT measurements (P>0.05), alveolar vertical height in other points and alveolar width measurements were statically significant (P<0.05). After 6 months, 10 sites of 10 subjects were received a flap and re-entered to perform dental implants surgery. The vertical height in the center of alveolar increased significantly and the changes of alveolar vertical height of clinical direct and CBCT measurement were (6.15 ± 1.73) mm and (6.59 ± 2.53) mm, respectively. The measurements of the width of the alveolar bone were (8.45 ± 1.18) mm and (8.52 ± 1.27) mm, respectively. The measurements of the two methods were not statistically significant (P>0.05). The change of the alveolar height in the center of the extraction socket after six months measured by parallel periapical was (5.84 ± 4.28) mm, which was closed to the clinical direct measurement and the CBCT measurement.

Clinical direct measurement and CBCT measurement were largely consistent in the evaluation of the alveolar bone height and width after the alveolar ridge preservation using deproteinized boving bone mineral (DBBM, Bio-Oss) and bioabsorbable collagen membrane (Bio-Gide) in periodontal compromised molar sites of severe bone defects.