Mariana Boessio Vizzotto

Detection of vertical root fractures by conventional radiographic examination and cone beam computed tomography – an in vitro analysis

OBJECTIVES  This study compared the ability of conventional radiographic and cone beam computed tomography (CBCT) examinations to detect vertical root fractures (VRF) in teeth with or without root canal treatment and metallic posts. Furthermore, the influence of using different voxel sizes from CBCT images was assessed. METHODOLOGY  Sixty single-rooted human teeth were randomly divided into two groups: experimental and control. Twenty teeth were endodontically prepared and obturated with gutta-percha, twenty had a metallic postcemented after the filling, and twenty had no preparation. The teeth from the experimental group were fractured. All teeth were radiographed with three different horizontal angles, and after, CBCT images were acquired following three protocols in which the variation was the voxel resolution (0.4, 0.3, and 0.2 mm). Three calibrated examiners assessed the images. RESULTS  Chi-squared test showed no statistical difference among the images in detecting VRFs. The results of the diagnostic performance tests presented similar ability to detect VRFs when conventional radiographic examination was compared with 0.2 and 0.3-voxel CBCTs scans, in roots without endodontic treatment and metallic post. Moreover, specificity, sensitivity, and accuracy findings were similar for both 0.2 and 0.3-voxel resolution scans for teeth that are not root filled. However, it was observed that in teeth with root canal treatment and a post, the accuracy was higher when 0.2-mm voxel resolution was used. CONCLUSION  The radiographic examination with horizontal angle variation should be encouraged as the first complementary approach to assess the presence of VRFs. If conventional imaging is not capable to provide adequate information, CBCT can be indicated if a root fracture is strongly suspected. The root condition should then guide the voxel resolution choice, selecting 0.3-voxel for not root filled teeth and 0.2-voxel for teeth with filling and/or a post.

A comparative study of lateral cephalograms and cone-beam computed tomographic images in upper airway assessment

The purpose of this study was to evaluate the accuracy of airway measurements from lateral cephalograms, cone-beam computed tomographic (CBCT) lateral reconstructions, and CBCT axial planes, as well as to correlate these findings with area measurements acquired with the latter imaging method. Landmarks were defined for the measurements of naso- and oropharynx of 30 patients (12 males and 18 females, mean age 17.5 years), for different planes, using linear antero-posterior measurements and the corresponding area. Analysis of variance showed significant differences in the linear measurements of the oropharynx between the two methods, although all measurements assessed corresponded to the respective areas. The linear measurements of the airway space obtained using the different techniques correlated positively with the respective area measurements, which demonstrate the reliability of the investigated techniques.

Development of a new in vitro methodology to simulate internal root resorption.

INTRODUCTION Studies to evaluate the diagnostic power of imaging examinations to detect root resorption have been based on simulations produced by burs. Standardized, round, and well-outlined access cavities do not reproduce the characteristics of physiological lesions and may facilitate diagnosis, masking the true accuracy of imaging techniques. A methodology to simulate internal root resorption by using acid demineralization was developed. METHODS Eleven extracted single-rooted teeth were mesiodistally sectioned into homologous halves. Root canals were labeled to ensure restricted and controlled action of fluids. The protocol was composed of 24-hour cycles (5% nitric acid for 12 hours, rinsing with deionized water, and 8% sodium hypochlorite for 10 minutes). At the end of each cycle 1 tooth was removed from treatment, defining an exposure time that cumulated to the last tooth. Electron microscopy imaging was assessed to determine lesion area and depth. RESULTS Minimum and maximum and areas and depths were 3.14 mm² and 10.34 mm² and 0.22 mm and 1.59 mm, respectively. Resorption simulated by the protocol proposed reproduced lesions of different sizes. CONCLUSIONS The irregular shape and larger diameter:depth ratio suggest that these lesions are more similar to in vivo internal root resorption, compared with bur-induced lesions.

Buccal-lingual localization of the mandibular canal in relationship with the third molar using the lateral oblique technique

Aim: The aim of this study was to evaluate the use of lateral oblique radiography (LOR) at two different incidence angles for the bucco-lingual topographic localization of the mandibular canal with respect to the lower third molars. Materials And Method: A total of 24 dry jaws bearing at least one third molar were subject to LOR at vertical incidence angles of 0° and -30°. A trained and calibrated examiner measured the distance between the top of the mandibular canal to the most apical point of the third molar, using a digital calliper and individual light box for the radiographs. Based on the analysis of the two measurements (incidence angles of 0° and -30°) and considering the buccal object rule, the observer estimated the location of the mandibular canal, which was classified as lingual, central or buccal to the corresponding third molar. Results were compared with the computerized tomography images (gold standard). Results: The statistical analysis included sensitivity, specificity and accuracy tests. These results showed that LOR (0° e -30°) could be used to determine the bucco-lingual location of the mandibular canal with respect to the third molar. Conclusion: In spite of the magnification, LOR images demonstrated that the technique could be used for this study proposal.

Imaging evaluating of the implant/bone interface—an in vitro radiographic study

OBJECTIVES To analyze the diagnostic accuracy of conventional and digital radiographic images and the impact of digital filters in evaluating the bone-implant interface. METHODS Titanium implants were inserted into 74 fresh bovine ribs blocks, 37 fitting tight to the bone walls (simulating the existence of osseointegration) and 37 with a gap of 0.125 mm (simulating a failure in the osseointegration process). Periapical radiographs were taken with conventional film and two phosphor plate systems [VistaScan® (Dürr Dental, Bietigheim-Bissingen, Germany) and Express® (Instrumentarium, Tuusula, Finland)]. Digital radiographs were investigated with and without enhancement filters. Three blinded examiners assessed the images for the presence of juxtaposition in the bone-implant interface using a five-point Likert scale. Sensitivity, specificity and the area under the receiver-operating characteristic curve (AUC) and its 95% confidence interval (CI) were calculated for each variable. Intraexaminer and interexaminer agreements were analyzed using Kendalls concordance test. RESULTS Intraexaminer and interexaminer agreements were >0.80 for both digital and conventional images. Conventional radiographs (AUC = 0.963/CI = 0.891 to 0.993) and digital images with high enhancement filters such as Caries2 (AUC = 0.964/CI = 0.892 to 0.993), Endo (AUC = 0.952/CI = 0.875 to 0.988) and Sharpen3 (AUC = 0.894/CI = 0.801 to 0.954) showed the greatest accuracy for evaluating the bone-implant interface. Original images from both digital systems and the further enhancement filters tested showed low sensitivity for the diagnosis task tested. CONCLUSIONS Conventional radiographs or digital radiographs with high-pass filters could help enhance diagnosis on implant-bone interface.

Airway volume analysis: is there a correlation between two and three-dimensions?

Objectives No consensus exists on the assessment of airway in CBCT scans. Two-dimensional measures remain the standard in the cephalometric analysis. This research aimed to evaluate linear and area measurements in two-dimensional views from specific airway regions of interest and compare these to the correspondent volume in CBCT exams. Materials and Methods 250-selected CBCT scans were retrospectively analyzed. A trained and calibrated examiner performed the linear, area and volume measurements in specific sites for nasal cavity, nasopharynx and oropharynx compartments. Dolphin Software was used for the analysis. The correlations were performed using Pearson coefficient. Results The highest positive correlations were observed in the nasopharynx and oropharynx sagittal areas and the most constricted area in the oropharynx. Nasopharynx linear measures and nasopharynx coronal area did not present correlation with whole volume. Two-dimensional measurements in the soft palate (width and sagittal area) showed very low positive correlations. Although nasal cavity presented highest volume means, changes in oropharynx contributed more to variations in total volume, compared with the other two sections. Conclusion Airway sagittal areas, as well as the most constricted axial area in oropharynx remains a useful guide to correlate with airway volume in two-dimensional images.

Is cone beam computed tomography accurate for postoperative evaluation of implants? An in vitro study

OBJECTIVE The aim of this study was to evaluate the accuracy of cone beam computed tomography (CBCT) for evaluation of the bone-implant interface in comparison with periapical radiography. STUDY DESIGN Titanium implants were inserted in 74 bovine rib blocks in intimate contact with bone walls and with a gap of 0.125 mm (simulating failure in the osseointegration process). Periapical radiographs were taken with conventional film, and CBCT scans were acquired with i-CAT (0.2 mm and 0.125 mm voxel) and Kodak (0.2 mm and 0.076 mm voxel) units. Three examiners evaluated the images using a 5-point scale. Diagnostic accuracy was analyzed through sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve (AUC) with 95% confidence intervals (CIs). Intra- and interexaminer agreements were analyzed through Kendalls concordance test. RESULTS Intra- and interexaminer agreements showed satisfactory results. The greatest accuracy was observed with conventional radiography (AUC = 0.963; CI 95% = 0.891-0.993). I-CAT 0.125-mm images showed good accuracy (AUC = 0.885; CI 95% = 0.790-0.947), with no significant difference compared with conventional radiography. Kodak images had high specificity and low sensitivity, presenting more false-negative results. CONCLUSIONS Conventional radiography showed the highest accuracy for assessment of the bone-implant interface. However, CBCT (i-CAT; 0.125-mm voxel), if available or if performed for preoperative assessment of another implant site, may provide similar accuracy.

Development and evaluation of an extraoral radiographic simulator model

Objectives: To describe the development of an extraoral radiographic simulator model that allows the demonstrations of head position and practical training of extraoral radiographic techniques and its usability evaluation by the users. Methods: It was used a macerated human skull, autopolymerising acrylic resin, orthodontic elastics, screws, polyvinyl chloride pipe and a photograph tripod to build it. After theoretical and demonstration classes, and practical training using the simulator model, twenty-nine professionals from the last five classes of an Oral Radiology Specialization Course filled out a form to evaluate its usability. Results: the modified SUS (System Usability Scale) final score obtained for usability was eighty-three, indicating high acceptance of the simulator model. Conclusion: this extraoral radiographic simulator model can be built at a very low cost, is useful for practice extraoral radiographic techniques and it should be encouraging its use as a teaching aid in other institutions. Correspondence to: Heraldo Luis Dias da Silveira, Dental School – Federal University of Rio Grande do Sul, Oral Radiology Division, Rua Ramiro Barcelos, 2492/5 floor, Porto Alegre, RS – Brazil, Tel: 55–51–33085199, E-mail: heraldo@ufrgs.br

Diagnostic reproducibility of the second mesiobuccal canal by CBCT: influence of potential factors

ObjectivesThe use of cone-beam computed tomography (CBCT) in endodontics includes the assessment of endodontic pathologies, presurgical planning, and canal morphology. The performance of CBCT scans to observe pathologic conditions and anatomic structures in three-dimensional reconstructions has proven to be incredibly useful. The quality of the images, the conditions for their analysis, and the operator’s skill and care during the image acquisition strongly affect the incidence of diagnostic errors. In the same way, the validity of any test for diagnosis depends on its reliability. The purpose of this study was to assess the ability of three observers to accurately confirm the existence and absence of MB2 canals in human first upper molars with different root conditions.MethodsThree trained and calibrated dentists from a postgraduate program on oral and maxillofacial radiology were asked to identify MB2 canals in 82 extracted human first upper molars under different conditions depending on the MB1 root canal (non-filled, filled, and deobturated). Kappa values among the observers were obtained.ResultsThe agreement among the examiners ranged from 0.39 to 0.68. The kappa values were more impaired by the root condition than by the voxel size. Moreover, experience in CBCT image evaluation played a role in agreement among the examiners.ConclusionsThe results suggest that root condition and professional experience have more influence for agreement during MB2 diagnosis than voxel size.

Importance of diagnosing invasive cervical resorption

Root resorption is the loss of dental hard tissues as a result of physiological or pathological clastic activity. Invasive cervical resorption is the clinical term used to describe a pathological form of relatively uncommon, insidious and aggressive resorption of the tooth, which may be asymptomatic and often undiagnosed, and occur in any tooth of the permanent dentition. It is usually a casual finding of radiographic routine or initial orthodontic records. This paper reports a case of invasive cervical resorption, and aims to raise awareness of potential occurrence of this type of lesion and highlight the importance of early diagnosis by dentists, radiologists and orthodontists who are often the first specialists to come across these kinds of images. Treatment will rely on the development of the lesion. In its initial stage, conservative therapy can be applied; while in advanced cases, radical treatment, such as tooth extraction, is the therapy of choice. The severity of the lesion will guide the choice for the best procedure.