Cone-beam là gì? Các công bố khoa học về Cone-beam

Objective: To determine the thickness of the facial bone wall in the anterior dentition of the maxilla and at different locations apical to the cemento‐enamel junction (CEJ).

Material and methods: Two‐hundred and fifty subjects, aged between 17 and 66 years, with all maxillary front teeth present were included. Written informed consents were obtained. Cone‐beam computed tomography scans were performed with the iCAT unit. This examination included all tooth and edentulous sites in the dentition. The images were acquired by means of the iCAT software and processed by a computer. Measurements of the (i) distance between the CEJ and the facial bone crest and (ii) the thickness of the facial bone wall were performed. The bone wall dimensions were assessed at three different positions in relation to the facial bone crest, i.e., at distances of 1, 3, and 5 mm apical to the crest.

Results: The measurements demonstrated that (i) the distance between the CEJ and the facial bone crest varied between 1.6 and 3 mm and (ii) the facial bone wall in most locations in all tooth sites examined was ≤1 mm thick and that close to 50% of sites had a bone wall thickness that was ≤0.5 mm.

Conclusion: Most tooth sites in the anterior maxilla have a thin facial bone wall. Such a thin bone wall may undergo marked dimensional diminution following tooth extraction. This fact must be considered before tooth removal and the planning of rehabilitation in the anterior segment of the dentition in the maxilla.

To cite this article: 
Januário AL, Duarte WR, Barriviera M, Mesti JC, Araújo MG, Lindhe J. Dimension of the facial bone wall in the anterior maxilla: a cone‐beam computed tomography study.
Clin. Oral Impl. Res. 22, 2011; 1168–1171
doi: 10.1111/j.1600‐0501.2010.02086.x.
10.1111/j.1600‐0501.2010.02086.x

Aim  To compare the accuracy of intraoral periapical radiography with cone beam computed tomography (CBCT) for the detection and management of resorption lesions.

Methodology  Digital intraoral radiographs and CBCT scans were taken of patients with internal resorption (n = 5), external cervical resorption (n = 5) and no resorption (controls) (n = 5). A ‘reference standard’ diagnosis and treatment plan was devised for each tooth. Sensitivity, specificity, positive predictive values, negative predictive values and receiver operator characteristic (ROC) curves, as well as the reproducibility of each technique were determined for diagnostic accuracy and treatment option chosen.

Results  The intraoral radiography ROC Az values were 0.780 and 0.830 for diagnostic accuracy of internal and external cervical resorption respectively. The CBCT ROC Az values were 1.000 for both internal and external cervical resorption. There was a significantly higher prevalence (P = 0.028) for the correct treatment option being chosen with CBCT (%) compared with intraoral radiographs (%).

Conclusion  CBCT was effective and reliable in detecting the presence of resorption lesions. Although digital intraoral radiography resulted in an acceptable level of accuracy, the superior accuracy of CBCT may result in a review of the radiographic techniques used for assessing the type of resorption lesion present. CBCT’s superior diagnostic accuracy also resulted in an increased likelihood of correct management of resorption lesions.