Assessment of thin bony structures using cone-beam computed tomography.

OBJECTIVES: To investigate the validity and reliability of marginal bone level measurements on cone-beam computed tomography (CBCT) images of thin bony structures using various reconstruction techniques, two image resolutions, and two viewing modes. MATERIALS AND METHODS: CBCT and histologic measurements of the buccal and lingual aspects of 16 anterior mandibular teeth from 6 human specimens were compared. Multiplanar (MPR) and three-dimensional (3D) reconstructions, standard and high resolutions, and gray scale and inverted gray scale viewing modes were assessed. RESULTS: Validity of radiologic and histologic comparisons were highest using the standard protocol, MPR, and the inverted gray scale viewing mode (mean difference = 0.02 mm) and lowest using a high-resolution protocol and 3D-rendered images (mean difference = 1.10 mm). Mean differences were significant (P < .05) at the lingual surfaces for both reconstructions, viewing modes (MPR windows), and resolutions. CONCLUSIONS: Varying the reconstruction technique and viewing mode does not improve the observer's ability to visualize thin bony structures in the anterior mandibular region. The use of 3D-reconstructed images should be avoided when thin cortical borders are suspected. The small difference when using a high-resolution protocol is unjustified due to the higher radiation dose required. Previous studies have focused on technical parameters; the present study explores the next link in the imaging chain.

Ridge preservation using Collacone compared with an empty socket: a pilot study.

OBJECTIVES: The objective of this study was to evaluate the dimensional changes in alveolar bone and soft tissue after dental extraction/postextraction in alveoli filled/grafted with collagen (Collacone) compared with those left empty/ungrafted. STUDY DESIGN: Twenty-three patients with a single maxillary incisor to be extracted were included in the study. The patients were randomized into either the treatment group, receiving a collagen sponge, or into the control group with an empty alveolus. All participants were examined and followed with cone beam computed tomography and 3-dimensional soft tissue scanning procedures during the healing process. The outcomes were statistically evaluated with Mann-Whitney U tests. RESULTS: Seventeen patients were available for follow-up. The radiographic outcome showed an average loss of bone in the bucco-palatal width of 1.15 mm (range, 0.2-2.2) in the test group and 0.57 mm (range, 0-1.6) among the controls. There was no significant difference between the 2 groups (P = .092). The soft tissue topography height measurements revealed an average decrease of 1.737 mm (range, 0.118-2.872) in the test group and 1.899 mm (range, 0.454-3.014) in the control group. The difference was not significant (P = .847). CONCLUSION: The use of a Collacone collagen sponge does not enhance the bone and soft tissue healing outcome after extraction of an incisor in the maxilla compared with leaving the alveolus empty.