Frab Noberto Bóscolo

Correlation of panoramic radiography and cone beam CT findings in the assessment of the relationship between impacted mandibular third molars and the mandibular canal

OBJECTIVES The aim of this study was to assess the reliability of four panoramic radiographic findings, both individually and in association, in predicting the absence of corticalization between the mandibular canal and the third molar on cone beam CT (CBCT) images. METHODS The sample consisted of 72 individuals (142 mandibular third molars) who underwent pre-operative radiographic evaluation before extraction of impacted mandibular third molars. On panoramic radiographs, the most common signs of corticalization (darkening of roots, diversion of mandibular canal, narrowing of mandibular canal and interruption of white line) and the presence or absence of corticalization between the mandibular third molar and the mandibular canal on CBCT images were evaluated. RESULTS Darkening of roots and interruption of white line associated with the absence of corticalization between the mandibular third molar and the mandibular canal on CBCT images were statistically significant, both as isolated findings (p = 0.0001 and p = 0.0006, respectively) and in association (p = 0.002). No statistically significant association was observed for the other panoramic radiographic findings, either individually or in association (p > 0.05). CONCLUSION Darkening of roots and interruption of white line observed on panoramic radiographs, both as isolated findings and in association, were effective in determining the risk relationship between the tooth roots and the mandibular canal, requiring three-dimensional evaluation of the case.

Comparison of digital systems and conventional dental film for the detection of approximal enamel caries

OBJECTIVES The aims of this study were (1) to compare the accuracy of the detection of approximal enamel caries lesions using three intraoral storage phosphor plate digital systems and one conventional film-based radiographic system; and (2) to determine whether there is a correlation between the histological and radiographic measurements of enamel caries. METHODS 160 approximal surfaces were radiographed under standardized conditions using three storage phosphor stimulable systems (DenOptix and Digora FMX with white and blue plates), and one film system (Insight film). 17 observers scored the images for the presence and depth of caries using a 4-point scale. The presence of caries was validated histologically (gold standard). Two-way analysis of variance was used to test the differences in sensitivity, specificity and overall accuracy (TP + TN). The data from the radiographic and histological measurements were statistically analysed by Spearmans rank correlation coefficient. RESULTS Two-way analysis of variance and the post hoc t-test demonstrated that Digora (white plate) had higher specificity and overall accuracy values than DenOptix (P = 0.021); there was no statistically significant difference among the other imaging modalities (P > 0.05). There was no significant correlation between the histological depth measurements and the radiographic measurements from Digora (blue plate) (P = 0.43), Digora (white plate) (P = 0.15), DenOptix (P = 0.17) and Insight film (P = 0.06). CONCLUSIONS The results suggest that (1) the performance of the three storage phosphor image plate systems was similar to that of the Insight film for detection of approximal enamel caries, and (2) the increase in histological depth of enamel caries was not significantly correlated with radiographic measurements.

Tonsillolith--report of an unusual case.

Tonsilloliths are rare concretions found in the tonsillar crypt. They are usually single and unilateral, but occasionally may be multiple or bilateral. This report describes a case of a 47-year-old woman whose radiography revealed one radiopaque image located in the right ramus of the mandible. The patient revealed a history of slight dysphagia, halitosis and swallowing pain with a foreign body sensation. Her medical history revealed a tonsillectomy when she was eight years old and the removal of the uvula because of sleep apnoea six years ago. Computer tomography showed a delimited and calcified oval image measuring 0.6 × 0.6 cm. The tonsillar concretion might have been formed because of a calcification of the lymphoid tissue. On the patients request, surgical excision was not performed and she will be monitored due to the tendency of such lesions to grow.

Influence of cone beam CT enhancement filters on diagnosis ability of longitudinal root fractures

OBJECTIVES To determine whether cone beam CT (CBCT) enhancement filters influence the diagnosis of longitudinal root fractures. METHODS 40 extracted human posterior teeth were endodontically prepared, and fractures with no separation of fragments were made in 20 teeth of this sample. The teeth were placed in a dry mandible and scanned using a Classic i-CAT® CBCT device (Imaging Sciences International, Inc., Hatfield, PA). Evaluations were performed with and without CBCT filters (Sharpen Mild, Sharpen Super Mild, S9, Sharpen, Sharpen 3 × 3, Angio Sharpen Medium 5 × 5, Angio Sharpen High 5 × 5 and Shadow 3 × 3) by three oral radiologists. Inter- and intraobserver agreement was calculated by the kappa test. Accuracy, sensitivity, specificity and positive and negative predictive values were determined. McNemar test was applied for agreement between all images vs the gold standard and original images vs images with filters (p < 0.05). RESULTS Means of intraobserver agreement ranged from good to excellent. Angio Sharpen Medium 5 × 5 filter obtained the highest positive predictive value (80.0%) and specificity value (76.5%). Angio Sharpen High 5 × 5 filter obtained the highest sensitivity (78.9%) and accuracy (77.5%) value. Negative predictive value was the highest (82.9%) for S9 filter. The McNemar test showed no statistically significant differences between images with and without CBCT filters (p > 0.05). CONCLUSIONS Although no statistical differences was observed in the diagnosis of root fractures when using filters, these filters seem to improve diagnostic capacity for longitudinal root fractures. Further in vitro studies with endodontic-treated teeth and research in vivo should be considered.

Comparison of transcranial radiograph and magnetic resonance imaging in the evaluation of mandibular condyle position.

OBJECTIVES Several image modalities have been used to assess the condylar position in the glenoid fossa. However, despite the development of more advanced techniques for imaging the temporomandibular joint (TMJ), the transcranial projection remains widely used in dentistry. The purpose of this study was to compare the condylar position in transcranial radiography (TRANS) with MRI. METHODS 70 matched pairs of TMJs (35 patients) who had undergone TRANS and MRI were evaluated. The TRANS scans were compared with the lateral, central and medial MRI scans, and the condylar position was assessed in the closed and open mouth position according to subjective and objective methods. The sensitivity, specificity and accuracy values were calculated for each group and Bowkers test was used to analyse the data. RESULTS There was no statistical significance between TRANS and MRI (P > 0.05). However, even though there were similar mean values between them, the comparison with the lateral image showed higher values, which might be due to TRANS representing the lateral one-third of the condyle. CONCLUSIONS It can be concluded that TRANS seems to be an acceptable method and its applicability as an adjunctive method in the condylar position should not be rejected.

Efficacy of lead foil for reducing doses in the head and neck: a simulation study using digital intraoral systems

OBJECTIVES To assess the efficacy of lead foils in reducing the radiation dose received by different anatomical sites of the head and neck during periapical intraoral examinations performed with digital systems. METHODS Images were acquired through four different manners: phosphor plate (PSP; VistaScan(®) system; Dürr Dental GmbH, Bissingen, Germany) alone, PSP plus lead foil, complementary metal oxide semiconductor (CMOS; DIGORA(®) Toto, Soredex(®), Tuusula, Finland) alone and CMOS plus lead foil. Radiation dose was measured after a full-mouth periapical series (14 radiographs) using the long-cone paralleling technique. Lithium fluoride (LiF 100) thermoluminescent dosemeters were placed in an anthropomorphic phantom at points corresponding to the tongue, thyroid, crystalline lenses, parotid glands and maxillary sinuses. RESULTS Dosemeter readings demonstrated the efficacy of the addition of lead foil in the intraoral digital X-ray systems provided in reducing organ doses in the selected structures, approximately 32% in the PSP system and 59% in the CMOS system. CONCLUSIONS The use of lead foils associated with digital X-ray sensors is an effective alternative for the protection of different anatomical sites of the head and neck during full-mouth periapical series acquisition.

Alternative X-ray filters for an intra-oral digital radiographic system

OBJECTIVE The aim of this study was to evaluate the effect of the modulation of the radiation spectrum with the use of alternative X-ray filters in the quality of intra-oral digital images from storage phosphor plates. METHODS The radiographic exposures were performed in a GE 1000 X-ray machine (General Electric Co., Milwaukee, WI), operating at 65 kVp, 10 mA, 40 cm focus receptor distance using three different exposure times: 0.05 s, 0.16 s and 0.35 s. The control filter (GC) was 100% aluminium (Al) with a thickness of 1.5 mm. The tested filters were: G1, 97% Al and 3% copper (Cu) with 1.47 mm thickness; G2, 96% Al and 4% Cu with 1.53 mm thickness; G3, 95% Al and 5% zinc (Zn) with 1.56 mm thickness; G4, 98% Al and 2% Zn with 1.5 mm thickness; and G5, 95% Cu and 5% Zn with 1.6 mm thickness. For formation of the image, a 12-step Al wedge (each step with increments of 1 mm in thickness) was radiographed 10 times. Pixel values measured in digital images were converted into optical density (OD). RESULTS All replicates showed OD with high reproducibility (r > 0.95) for all exposure times and tested filters. In comparison between filters, statistically significant differences in density (p < 0.05) were observed. The OD curve of the G5 filter in all exposure times and G3 filter in an exposure time of 0.05 s showed changes in shape (p < 0.05). CONCLUSIONS Excluding the G5 filter, all others tested filters can be used as a substitute for GC without losses in image quality.

Determination of the length of zygomatic implants through computed tomography: establishing a protocol

OBJECTIVES The aim of this study was to establish and verify an examination protocol using CT to estimate the length of zygomatic implants, thus rendering the surgical process safer and more predictable, and exposing the patient to a minimal level of radiation. METHODS Paracoronal CT scan was carried out on ten dry human crania (n = 20) and the zygomatic implant sites were measured (L(CT)) bilaterally. A standard surgical zygomatic implant placement procedure was carried out and the actual lengths (L(Real)) and clinical lengths (L(Clin)) determined. RESULTS The averages of the L(CT), L(Clin) and L(Real) were 45.73 +/- 4.82 mm, 42.63 +/- 4.33 mm, and 44.73 +/- 4.53 mm, respectively. Students t-test revealed no statistically significant differences between the L(Real) and L(CT) averages (P = 0.1532), whereas the L(Real) and L(Clin) averages were statistically different (P < 0.0001). CONCLUSIONS The proposed protocol proved to be precise and efficacious in the determination of zygomatic implant length, with the advantage to the patient of a relatively low level of exposure to radiation due to the small quantity of tomographic slices used. Although there were no major repercussions, the clinical probe in the zygomatic implant kit commonly used in this surgical procedure proved to be a rather imprecise tool.

Correlation between midline deviation and condylar position in patients with Class II malocclusion: A cone-beam computed tomography evaluation

Introduction: Midline deviation of the mandible and maxilla can affect craniofacial growth and occlusion and cause consequences to the temporomandibular joint. The aim of this study was to evaluate the lateral displacement of the skeletal and dental midlines in relation to the condyle head position in Class II patients with cone‐beam computed tomography. Methods: We used 82 cone‐beam computed tomography images. The lateral displacement of the skeletal and dental midlines considering the 3‐dimensional reference plane was analyzed with points in the maxillary and mandibular central incisors, anterior nasal spine, and menton. The condyle‐fossa relationship, concentric position of the condyles, and dimensional and positional symmetries between the right and left condyles were evaluated. Results: There was a statistically significant difference regarding anterior nasal spine with maxillary central incisor, menton, and mandibular central incisor points for both sides, and also for maxillary central incisor‐menton for the displacement of the left side. We found differences in the temporomandibular joint for inclination and diameter measurements of the condylar process. Strong correlations were observed between the maxilla and the condylar process diameter (right side) and the distance between the geometric centers (left side), in addition to a strong correlation between the sagittal midline displacement and the geometric center differences on the right and left sides. Conclusions: In patients with Class II malocclusion, lateral displacement of skeletal and dental midlines in relation to the condyle head position has a significant correlation with the anteroposterior difference between the geometric center of the right and left condylar processes. HIGHLIGHTSLateral displacements of the skeletal and dental midlines in relation to the condyle were measured.Three‐dimensional CBCT images show applicability for the diagnosis of facial asymmetry.Correlation was found between center of the right and left condyles in relation to midline change.

Correlation between the position of hyoid bone and subregions of the pharyngeal airway space in lateral cephalometry and cone beam computed tomography

OBJECTIVE To correlate the pharyngeal airway subregions with the positioning of the hyoid bone. MATERIAL AND METHODS The study examined 107 lateral cephalometric (LC) and cone beam computed tomography (CBCT) images. Linear and volumetric measurements of the pharyngeal subregions were made and correlated to linear measurements using hyoid triangle analysis on images of LC and multiplanar (MPR) and three-dimensional (3D) reconstructions of CBCT. RESULTS There was significant correlation between linear measurements of the pharyngeal subregions and hyoid bone position in LC images and in MPR and 3D reconstructions of the CBCT. Correlations were more frequent in the oropharynx and hypopharynx, especially for LC images. No correlations were observed between LC images or CBCT reconstructions and the volumetric measurements of the pharyngeal subregions and the position of the hyoid bone. CONCLUSION The hyoid bone position showed more correlations with oropharynx and hypopharynx airway measurements. The hyoid triangle method was not applicable to 3D images, since it showed a smaller number of measures correlated to the hyoid bone position.