Sergio Lins de Azevedo Vaz

Evaluation of reconstructed images with different voxel sizes of acquisition in the diagnosis of simulated external root resorption using cone beam computed tomography

AIM   To evaluate the diagnosis of simulated external root resorption in cone beam computed tomography (CBCT) images acquired with different voxel sizes, then reconstructed with the same voxel size. METHODOLOGY   Buccal, mesial and distal root surfaces of twenty single-rooted premolar teeth were evaluated for the presence or absence of simulated resorption defects. Images were obtained using a Classic i-CAT CBCT unit with two different voxel sizes (0.25 and 0.30 mm). Then all images were reconstructed to 0.25 mm voxel size. The McNemars test was applied to evaluate the agreement between the two protocols (different voxel sizes/reconstruction parameters) with the gold standard (defects created in the root). Accuracy, sensitivity, specificity, positive and negative predictive values were calculated for each voxel and defect sizes. RESULTS   Better sensitivity and accuracy were obtained with 0.25 (0.25 mm) voxel size. Specificity, positive and negative predictive values were highest with the 0.25 (0.30 mm) voxel size. McNemars test results revealed significant differences between the protocols with the gold standard (P < 0.0001). The results revealed that as the cavity size increased, sensitivity, accuracy, positive and negative predictive values also increased. When correlating the voxel size and root third, better sensitivity, accuracy, positive and negative predictive values were obtained in the middle third. CONCLUSIONS   In the diagnosis of simulated external root resorption with the Classic i-CAT CBCT unit, images acquired with 0.30 mm voxel size and reconstructed with 0.25 mm voxel size provided the best protocol with a lower radiation dose than the 0.25 mm voxel size.

Influence of Cone-Beam Computed Tomography Enhancement Filters on Diagnosis of Simulated External Root Resorption

INTRODUCTION The aim of this study was to determine if cone-beam computed tomography (CBCT) enhancement filters influence the diagnosis of simulated external root resorption (ERR). METHODS Buccal, mesial, and distal root surfaces of 20 single-rooted premolar teeth were evaluated for the presence or absence of simulated defects. Images were obtained using a Classic i-CAT CBCT device (Imaging Sciences International, Inc, Hatfield, PA) and analyzed by 3 oral radiologists. Evaluations were performed with and without CBCT filters. Accuracy, sensitivity, specificity, and positive and negative predictive values were determined. The McNemar test verified the disagreement between all images versus the gold standard and original images versus images with filters; P values < .05 were considered statistically significant. Inter- and intraobserver agreement was calculated by the kappa test. RESULTS The means of intra- and interobserver agreement ranged from good to excellent. Sharpen 3×3 had the highest sensitivity (0.64), accuracy (0.62), and negative predictive value (0.33). Specificity was the highest (0.56) for S9, Smooth, Smooth 3×3, and Angio Sharpen High filters. Positive predictive values were the highest (0.81) for the Smooth 3×3 and Angio Sharpen High filters. The McNemar test showed statistically significant differences from the gold standard for all images (P < .05) as well as for original images versus images with the Shadow filter (P = .01). The other filters did not show statistically significant differences from the original images. CONCLUSIONS The influence of enhancement CBCT filters on ERR diagnosis is small. The Sharpen 3×3 filter gave the best results and the Shadow filter the worst results.

Usefulness of cone‐beam CT in the evaluation of a spontaneously healed root fracture case

Horizontal root fractures (HRF) usually affect anterior teeth of male patients as a result of trauma. The consequences can be complex because of combined damage to different tissues, but it has been reported that root fractures undergo healing in majority cases. Diagnosis of HRF must be based on clinical findings, sensibility tests, and radiographic examination. The cone-beam computed tomography (CBCT) has already been proven to be superior among other radiographic modalities for diagnostic imaging of root fractures. However, CBCT in these cases needs to be used in a careful manner, and only when the radiation exposure should be justified by the potential diagnostic benefits and improvement of the treatment results. This case report describes a case of spontaneously healed horizontal root fracture with displacement of the fragments and discusses the usefulness of CBCT in the follow-up of root fractures cases.

Accuracy of enhancement filters in measuring in vitro peri‐implant bone level

OBJECTIVES To identify the accuracy of enhancement filters of an intraoral phosphor-plate system for measuring the simulated peri-implant bone level. MATERIALS AND METHODS A total of 20 titanium implants (Titamax(®) ) were placed into six fragments of bovine ribs and defects simulating bone loss were created. Periapical radiographs were taken with a phosphor-plate system (Vista Scan(®) ) according to the paralleling standard technique, and nine enhancement filters were applied: fine, caries 1, caries 2, perio, endo, noise reduction, invert, emboss, and sculpture. The Friedman test compared the radiographic measurements of the defects to those obtained on the bovine ribs with a digital caliper. Intra- and interobserver agreement was calculated with the intra-class correlation coefficient (ICC). RESULTS The ICC values showed excellent intra- and interobserver agreement. The caries1, caries2, endo, and perio filters resulted on measurements statistically different from both the original images and the measurements of the digital caliper (P < 0.05). The other filters did not show statistically significant differences from the original images nor from the measurements of the digital caliper. CONCLUSION In addition to the original images, the fine and emboss filters resulted on the most precise measures. The caries1, caries2, endo, and perio filters were the less accurate for measuring the peri-implant bone level.

Association between maxillary sinus pathologies and healthy teeth

INTRODUCTION The proximity of the roots to the maxillary sinus can create a variety of risks. OBJECTIVE To evaluate the relationship between the roots of healthy teeth and the maxillary sinus, as well as the occurrence of sinus pathologies. METHODS Three radiologists analyzed 109 cone beam computed tomography (CBCT) images. The Kappa test was used to assess the intra- and inter-rater agreement. The chi-squared test and prevalence ratio were used to test the hypothesis that roots of healthy teeth in the maxillary sinus favored the occurrence of sinus pathologies (p=0.01). RESULTS Intra- and inter-rater agreement ranged from good to excellent. The chi-squared test demonstrated a statistically significant difference (p=0.006) between the tooth roots in diseased maxillary sinuses (6.09%) and those in normal sinuses (3.43%). The prevalence ratio test showed a statistically significant higher prevalence of tooth roots in diseased sinuses than in normal sinuses (p<0.0001). Roots in the maxillary sinus were 1.82 times more associated with diseased sinuses. CONCLUSION Dental roots in the maxillary sinus are almost twice as likely to be associated with diseased sinuses than normal sinuses. Healthy teeth whose roots are inside the maxillary sinus may induce an inflammatory response in the sinus membrane. It is suspected that dental procedures may exacerbate the condition.