Agenesia of salivary glands: incidental findings in multidetector computerized tomography.

Agenesis of the salivary glands is an extremely uncommon finding, and in the majority of cases, it is associated with facial syndromes or malformations. Reports in the literature have, however, indicated that agenesis of the major salivary glands can occur in isolation, and this anomaly is believed to occur due to a failure in the developmental process. Herein, we present two cases of isolated unilateral agenesis of major salivary glands.

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.

Evaluation of buccal bone coverage in the anterior region by cone-beam computed tomography.

INTRODUCTION: The purpose of this study was to compare the sensitivity of diagnoses of buccal bone coverage in anterior teeth between axial and sagittal reconstructions using cone-beam computed tomography. METHODS: Five dry skulls were clinically evaluated to detect bone defects in the anterior maxilla and mandible to establish a gold standard. The skulls were prepared and placed on a Kodak 9000 3-dimensional scanner (Trophy, Marne La Vallée, France) for image acquisition. The images were processed and reconstructed using Kodak Dental Imaging software 3-dimensional module (version 2.4; Kodak Dental Systems, Atlanta, Ga). All bone defects were identified and recorded. RESULTS: In the sagittal and axial reconstructions, regions without bone coverage were diagnosed in 91.03% of cases as "cortex not seen" or "minimum thickness, fine, without marrow bone." CONCLUSIONS: Cone-beam computed tomography can help in the diagnosis of lack of bone coverage on the buccal surfaces of anterior teeth. There was no difference in the performance of the axial and sagittal reconstructions.

Correlation between maxillofacial radiographic features and systemic severity as sickle cell disease severity predictor.

This study was conducted to investigate the relationship among radiographic features observed on panoramic radiographs of sickle cell disease patients and analyze their relationship with history of systemic severity of the disease. Panoramic radiographs of 71 subjects with sickle cell disease were evaluated for the presence of the following radiographic bony alterations: radiopaque areas, increased spacing of bony trabeculae, horizontal arrangement of bony trabeculae and corticalization of mandibular canal. History of clinical systemic severity was assessed through direct questioning about the frequency of vaso-occlusive crisis, history of stroke, clinical jaundice, femur head necrosis, and leg ulceration. Chi-square or Fisher's exact test were applied in order to analyze possible associations between radiographic features and history of complications, with p < 0.05 significance level. Increased spacing of bony trabeculae was statistically associated with absence of corticalization of mandibular canal (p < 0.01) and horizontal arrangement of bony trabeculae (p = 0.04). Statistically significant associations were demonstrated between history of clinical jaundice and presence of increased spacing of bony trabeculae (p = 0.02) and between history of stroke and presence of horizontal arrangement of bony trabeculae (p = 0.04). Based on the results of the current study, maxillofacial radiographic features may be associated with clinical parameters of systemic complications in sickle cell disease patients. The relationship between radiographic features and history of complications associated with clinical severity of sickle cell disease has not been demonstrated in the literature. Acknowledgment of such possible association may help establish prognosis and influence clinical treatment of systemic and oral complications.

Accuracy of linear measurements in cone beam computed tomography with different voxel sizes.

OBJECTIVE: To evaluate the accuracy of linear measurements on dry mandible specimens using cone beam computed tomography (CBCT) images acquired with different voxel sizes. METHODOLOGY: Eight human dry mandibles were submitted to CBCT examination, using the i-CAT (Imaging Sciences, Inc. Hatfield, PA) device and four protocols with different voxel sizes. Tomographic slices with a more central view of the markers, placed on six sites on each mandible, were selected to perform measurements. Values obtained from direct measurements on the dry mandible after sectioning them on the preestablished sites were compared with measurements from the tomographic images and the measurement error. RESULTS: There was no statistical difference between the measurement error of the protocols (P = 0.606). The mean value of the difference between the values obtained in the images and the dry mandible was smaller than 1 mm for all the protocols. CONCLUSION: The accuracy of vertical and horizontal measurements, using CBCT (i-CAT) for the four protocols, was shown to be comparable with the measurements performed on the dry mandible.

Risk assessment of inferior alveolar neurovascular bundle by multidetector computed tomography in extractions of third molars.

PURPOSE: This study aimed to assess the reliability of multidetector computed tomography (MDCT) in determining the surgical risk of the inferior alveolar neurovascular bundle in extractions of third molars. METHODS: The sample comprised thirty-three individuals (63 third molars) who underwent preoperative evaluation by MDCT before extraction of impacted mandibular third molars. MDCT was used to determine the relationship between the roots of the third molars and the mandibular canal, and the course of the mandibular canal. Inferior alveolar nerve (IAN) exposure and the presence of hemorrhage were analyzed after removal of the teeth. IAN neurosensory deficit was recorded after 7 days. Clinical and MDCT findings were compared using Fisher's exact test (P < 0.05). RESULTS: There was a statistically significant association between IAN exposure and the tomographic relationship between the roots of third molars and the mandibular canal (P = 0.015). Conventionally, all cases of IAN neurosensory deficit and hemorrhage occurred when the roots of the third molar presented in an at-risk relationship with the mandibular canal, however, this association was not statistically significant (P > 0.05). A statistically significant association was found between the lingual course of the mandibular canal and IAN exposure (P = 0.03). CONCLUSIONS: MDCT is an effective tool for determination of the surgical risk to the inferior alveolar neurovascular bundle in extraction of mandibular third molars.

Invasive cervical resorption of central incisor during orthodontic treatment.

INTRODUCTION: Invasive cervical resorption (ICR) is a relatively rare type of ERR (External Root Resorption), in which a localized resorption begins in the cervical area of the tooth, below the epithelial junction and above the ridge crest. OBJECTIVE: Describe the clinical case of an 11-year-old boy with no dental trauma history, presenting moderate crowding and ectopic eruption of the maxillary right central incisor. He had been undergoing orthodontic treatment elsewhere, and his family was dissatisfied with the results. DESCRIPTION: A new treatment was indicated, which included rapid maxillary expansion followed by extraction of four premolars. During routine panoramic evaluation, a radiolucid image was detected and a periapical radiograph was requested. At this point, an ICR of the maxillary right central incisor was found. The treatment was cautiously finalized and despite the use of light forces, central incisor was severally compromised by ICR and was therefore extracted. CONCLUSION: This clinical example discusses the importance of routine radiographs for the early diagnoses of ICR.

Correlation between temporomandibular joint morphometric measurements and gender, disk position, and condylar position.

OBJECTIVE: The aim of this study was to correlate the morphometric measurements of the temporomandibular joint, including condylar size, joint space, and articular eminence size, with gender, disk position, and condylar position by using magnetic resonance imaging. STUDY DESIGN: Overall, 93 patients were evaluated (31.2% males and 68.8% females; age 18-81 years; mean age 41 years). Condylar size (D1), joint space (D2), and eminence size (D3) were measured. Correlations with gender, disk position, and condylar position were calculated. RESULTS: A statistically significant correlation was found between D2 and gender, with the joint space being significantly larger in the male group (P = .05). There were correlations between D2 and the position of the disk and the position of the condyle (P ≤ .05). CONCLUSIONS: The results indicate a correlation between male gender and larger joint space. In addition, we found that the joint space size influences the articular disk and condyle position, which can cause disk displacement.

Application of a newly developed software program for image quality assessment in cone-beam computed tomography.

PURPOSE: The purpose of this study was to apply a newly developed free software program, at low cost and with minimal time, to evaluate the quality of dental and maxillofacial cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: A polymethyl methacrylate (PMMA) phantom, CQP-IFBA, was scanned in 3 CBCT units with 7 protocols. A macro program was developed, using the free software ImageJ, to automatically evaluate the image quality parameters. The image quality evaluation was based on 8 parameters: uniformity, the signal-to-noise ratio (SNR), noise, the contrast-to-noise ratio (CNR), spatial resolution, the artifact index, geometric accuracy, and low-contrast resolution. RESULTS: The image uniformity and noise depended on the protocol that was applied. Regarding the CNR, high-density structures were more sensitive to the effect of scanning parameters. There were no significant differences between SNR and CNR in centered and peripheral objects. The geometric accuracy assessment showed that all the distance measurements were lower than the real values. Low-contrast resolution was influenced by the scanning parameters, and the 1-mm rod present in the phantom was not depicted in any of the 3 CBCT units. Smaller voxel sizes presented higher spatial resolution. There were no significant differences among the protocols regarding artifact presence. CONCLUSION: This software package provided a fast, low-cost, and feasible method for the evaluation of image quality parameters in CBCT.

Relationship between articular eminence inclination and alterations of the mandibular condyle: a CBCT study.

This study aimed at verifying the correlation among angulation of the articular eminence (AE), shape of the condyle and its degenerative bone diseases (DBDs), according to age and sex, through Cone Beam Computed Tomography (CBCT). Five hundred and twenty-eight temporomandibular joints (TMJ) were evaluated. The condyles were classified as: flat, convex, angled and rounded, and the AE angulation was measured. The DBDs evaluated were osteophytes, flattening, erosion, subcortical cysts and spinal sclerosis. There was no difference in the mean angulations in relation to age group (p>0.05). In age groups of 60-69 years (p=0.003) and 70 years or over (p=0.021), the angulation was higher in males. There was an association between DBD and sex (p=0.047), in that the prevalence was higher in females. Differences in AE angles were not observed in condyles with one or no DBDs (p>0.05). However, the presence of two or more DBDs led to a decrease in the angle (p<0.05). Angled condyles showed higher AE angulations than the flat and convex types (p<0.01). In conclusion, the AE inclination is influenced by DBD and condyle shape; an association of two or more bone diseases in the condyle, or its flat or convex anatomy, results in a decrease in the angulation.

Assessment of condyle position, fossa morphology, and disk displacement in symptomatic patients.

OBJECTIVE: The aim of the study was to determine whether there are any associations between the morphology of the glenoid fossa, articular spaces, and disk displacement by evaluating the magnetic resonance imaging (MRI) scans of symptomatic patients. Gender and age were also evaluated for any effect on the parameters. STUDY DESIGN: MRI scans of 199 temporomandibular joints were assessed for the morphology of the glenoid fossa and articular spaces in both sagittal and coronal views. The presence of disk displacement and its type in closed-mouth and open-mouth positions were also assessed. Analysis of variance (ANOVA), Tukey, and Student t tests or Mann-Whitney rank sum tests were used to investigate the associations among these variables. RESULTS: A total of 113 joints (56.8%) were presented with disk displacement. The articular spaces observed in sagittal and coronal views were, overall, significantly larger in males than in females in 3 of the 6 spaces (superior, posterior, and central spaces). Larger superior and medial articular spaces were associated with angled glenoid fossae. Higher mean values of the articular space sizes were associated with normal disk position (P < .001), except for the anterior articular space. When displacement was identified, higher values of the articular space sizes were also associated with disk reduction in the open-mouth position (P < .05). CONCLUSIONS: Condyles in the central position in the coronal view and slightly anteriorly positioned in the sagittal view are less likely to present disk displacement.

Quantitative assessment of image artifacts from root filling materials on CBCT scans made using several exposure parameters.

PURPOSE: To quantify artifacts from different root filling materials in cone-beam computed tomography (CBCT) images acquired using different exposure parameters. MATERIALS AND METHODS: Fifteen single-rooted teeth were scanned using 8 different exposure protocols with 3 different filling materials and once without filling material as a control group. Artifact quantification was performed by a trained observer who made measurements in the central axial slice of all acquired images in a fixed region of interest using ImageJ. Hyperdense artifacts, hypodense artifacts, and the remaining tooth area were identified, and the percentages of hyperdense and hypodense artifacts, remaining tooth area, and tooth area affected by the artifacts were calculated. Artifacts were analyzed qualitatively by 2 observers using the following scores: absence (0), moderate presence (1), and high presence (2) for hypodense halos, hypodense lines, and hyperdense lines. Two-way ANOVA and the post-hoc Tukey test were used for quantitative and qualitative artifact analysis. The Dunnet test was also used for qualitative analysis. The significance level was set at P<.05. RESULTS: There were no significant interactions among the exposure parameters in the quantitative or qualitative analysis. Significant differences were observed among the studied filling materials in all quantitative analyses. In the qualitative analyses, all materials differed from the control group in terms of hypodense and hyperdense lines (P<.05). Fiberglass posts did not differ statistically from the control group in terms of hypodense halos (P>.05). CONCLUSION: Different exposure parameters did not affect the objective or subjective observations of artifacts in CBCT images; however, the filling materials used in endodontic restorations did affect both types of assessments.

Morphometric features of the mandibular condyle and association with disk abnormalities.

OBJECTIVE: The aim of this study was to evaluate the relationship between the morphometric characteristics of the condyle and temporomandibular joint (TMJ) disk displacement. STUDY DESIGN: One hundred and nine individuals who underwent magnetic resonance imaging of the TMJ were evaluated. Linear (D1: condyle width; D2: condyle thickness) and angular (A1: horizontal condylar angle; A2: anterior condylar angle; A3: medial condylar angle) measurements were made. These measurements were associated with articular disk displacement, with and without reduction. RESULTS: There was statistically significant association between limited D1 and D2 and between A1 above and A1 below the mean and displacement of the joint disk. There was statistically significant association between A2 and anterior displacement of the disk. Furthermore, thicker condyles and/or condyles with smaller horizontal angles and/or with smaller medial angles were associated with articular disk reduction. CONCLUSIONS: The morphometric characteristics of the bony components of the TMJ are related to articular disk displacement and with its reduction or nonreduction.

Efficacy of a cone beam computed tomography metal artifact reduction algorithm for the detection of peri-implant fenestrations and dehiscences.

OBJECTIVE: To determine whether the use of a metal artifact reduction (MAR) algorithm improves the detection of peri-implant fenestrations and dehiscences on cone beam computed tomography scans. STUDY DESIGN: One hundred titanium fixtures were implanted into bovine ribs after the creation of defects simulating fenestrations and dehiscences. Images were acquired using four different protocols, namely, A2 (MAR on, voxel 0.2 mm), A3 (MAR on, voxel 0.3 mm), B2 (MAR off, voxel 0.2 mm), and B3 (MAR off, voxel 0.3 mm). For all protocols, receiver operating characteristic (ROC) curves were determined. Values for the areas under the ROC curves (Az) were subjected to analysis of variance. RESULTS: Az values were not statistically different among protocols regardless of the defect type (P > .05). CONCLUSIONS: The MAR algorithm tested by us did not improve the diagnosis of peri-implant fenestrations and dehiscences with use of either the 0.2 mm or the 0.3 mm voxel sizes.

[Obstructive sleep apnea and hypopnea syndrome: cephalometric analysis]. / Síndrome da apnéia e hipopnéia obstrutiva do sono: análise cefalométrica.

Obstructive sleep apnea and hypopnea syndrome (OSAHS) are characterized by repeated pauses in breathing during sleep, usually associated with sleep interruption and decreased oxyhemoglobin saturation. Cephalometric analysis has become an important method in diagnosis, reporting specific craniofacial characteristics such as posterior air pharyngeal space, tongue length and hyoid position, which may predispose some people to develop SAHOS. The purpose of this revision is to present several anatomic aspects by cephalometric analysis that may have a predisposition to the development of upper airway occlusion.

Evaluation of temporomandibular joint disk displacement and its correlation with pain and osseous abnormalities in symptomatic young patients with magnetic resonance imaging.

OBJECTIVE: To evaluate the occurrence of temporomandibular joint disk displacement and its correlation with pain and osseous abnormalities using magnetic resonance imaging (MRI) in patients under 21 years of age. STUDY DESIGN: MRI images in open- and closed-mouth positions from 102 patients, under 21 years of age (mean age 17 years), were studied retrospectively. Patients were divided into six groups according to the disk-condyle relationship. Chi-square, Marascuilo procedure, and Cochran-Mantel-Haenszel tests were used to evaluate the relationships among pain, abnormalities, and the groups. RESULTS: There was a statistically significant correlation between bilateral disk displacement without reduction and pain (P = .011), and osseous changes (P < .0001). There was no proven link between pain and osseous abnormality (P = .414). CONCLUSION: Young patients are susceptible to all stages of disk displacement. There was a strong correlation only between each variable (osseous abnormalities and pain) and the most severe stage of disk displacement (bilateral disk displacement without reduction).

Invasive cervical resorption of central incisor during orthodontic treatment

ABSTRACT Introduction: Invasive cervical resorption (ICR) is a relatively rare type of ERR (External Root Resorption), in which a localized resorption begins in the cervical area of the tooth, below the epithelial junction and above the ridge crest. Objective: Describe the clinical case of an 11-year-old boy with no dental trauma history, presenting moderate crowding and ectopic eruption of the maxillary right central incisor. He had been undergoing orthodontic treatment elsewhere, and his family was dissatisfied with the results. Description: A new treatment was indicated, which included rapid maxillary expansion followed by extraction of four premolars. During routine panoramic evaluation, a radiolucid image was detected and a periapical radiograph was requested. At this point, an ICR of the maxillary right central incisor was found. The treatment was cautiously finalized and despite the use of light forces, central incisor was severally compromised by ICR and was therefore extracted. Conclusion: This clinical example discusses the importance of routine radiographs for the early diagnoses of ICR.

RESUMO Introdução: A reabsorção cervical invasiva (RCI) é um tipo relativamente raro de reabsorção radicular externa (RRE), no qual uma reabsorção localizada começa na região cervical do dente, abaixo da junção epitelial e acima da crista marginal. Objetivo: Descrever o caso clínico de um menino com 11 anos de idade, sem histórico de trauma dentário, apresentando apinhamento moderado e erupção ectópica do incisivo central superior. Ele realizava tratamento ortodôntico em outro local, mas sua família estava insatisfeita com os resultados. Descrição: Foi iniciado um novo tratamento, que incluiu a expansão rápida da maxila, seguida pela extração de quatro pré-molares. Durante a avaliação de rotina da radiografia panorâmica, uma imagem radiolúcida foi detectada, e uma radiografia periapical da região foi solicitada, sendo encontrada uma RCI no incisivo central superior direito. O tratamento foi finalizado com cautela e, apesar do uso de forças leves, o incisivo central estava seriamente comprometido pela RCI e, portanto, precisou ser extraído. Conclusão: Esse exemplo clínico discute a importância das radiografias de rotina para o diagnóstico precoce da RCI.

Evaluation of the relation between the horizontal condylar angle and the internal derangement of the TMJ - a magnetic resonance imaging study.

This research aimed at assessing the relation between the horizontal condylar angle (HCA) and the internal derangement (ID) of the temporomandibular joint (TMJ), as a result of interference by the TMJ disk, in individuals undergoing magnetic resonance (MR) scans. The sample included a total of 144 TMJs (sagittal and coronal views) of 72 subjects, 15 of whom were male and 57 female, with ages ranging from 15 to 70. The scans were made in a Signa system (GE) model at a magnetic field magnitude of 1.5 T. Sixty-eight TMJs were found to be normal, while 46 showed anterior displacement with reduction. Of these, 41 had some kind of adaptive change in the condyle, while 5 showed degenerative changes. Anterior displacement without reduction was found in 29 joints, 12 of which showed adaptative changes in the condyle, while 17 showed degenerative changes. Only one posterior displacement of the articular disk was recorded. For the TMJs in which disk displacement was found, such values achieved 24.69 on the right side, and 22.94 on the left side. Hence, it was possible for us to conclude that the HCA tends to increase in those TMJs where ID is present. For contralateral TMJs, a strong association was observed between HCA values (57.8%), state of normality (69.7%), and ID (66.7%). To corroborate such findings, a correlation between contralateral HCA values (63.31%) and the diagnosis for contralateral TMJs (68.05%) was determined. Thus, we could infer that there is a tendency between contralateral TMJs to share characteristics and conditions.

Evaluation of cone-beam computed tomography in the diagnosis of vertical root fractures: the influence of imaging modes and root canal materials.

INTRODUCTION: The purpose of this study was to evaluate the influence of cone-beam computed tomography (CBCT) imaging modes in the diagnosis of vertical root fractures with different intracanal materials. METHODS: The sample consisted of 30 single-rooted teeth divided into 3 groups (n = 10), control and complete and incomplete root fracture. In each tooth, different materials were used (gutta-percha, metal post, and fiber post) as well as no filling material. Each tooth/root was scanned in a 3D Accuitomo 170 CBCT device by using 4 different imaging modes (high-resolution, high-fidelity, high-speed, and standard). In addition, the dose-area product was calculated for each CBCT imaging mode. The images were randomly evaluated by 5 dentomaxillofacial radiologists. RESULTS: Complete root fractures were visualized more easily than incomplete fractures. The presence of metal post and gutta-percha negatively influenced the diagnosis of root fracture. Regarding the CBCT imaging modes, there was no influence for complete root fracture diagnosis. In cases of incomplete root fractures, high-fidelity, high-resolution, and standard had a higher diagnostic accuracy, especially in the fiber post and no filling groups. CONCLUSIONS: The CBCT imaging modes had little influence in the diagnosis of complete and incomplete root fractures, whereas the presence of intracanal material had greater impact on the diagnostic ability, demonstrating that CBCT is not beneficial for the diagnosis of root fractures when metal posts are present.

Influence of the milliamperage settings on cone beam computed tomography imaging for implant planning.

PURPOSE: To evaluate the influence of the milliamperage settings on cone beam computed tomography (CBCT) images for qualitative and quantitative preoperative implant planning. MATERIALS AND METHODS: Eight dry mandibles were scanned under different milliamperage values (2, 4, 6.3, 8, 10, 12, and 15 mA) available for selection on the Kodak 9000 CBCT unit. Cross-sectional slices of incisor, canine, premolar, first molar, and second molar regions were analyzed by three oral radiologists. A subjective image quality evaluation of the height measurements compared with the real measurements obtained in the mandible were performed. After 30 days, 25% of the sample was reevaluated to obtain the reproducibility of the results. RESULTS: The weighted-kappa coefficient and intraclass correlation coefficient for intra- and interobserver agreement varied between moderate and substantial agreement for the image quality evaluation, and excellent agreement was found for the bone measurements. For the image quality evaluation, the Friedman test showed a negative influence of the milliamperage setting only when the lowest values (2 and 4 mA) were used; for the measurements, one-way analysis of variance with the post hoc Tukey test showed that milliamperage settings did not influence their accuracy. However, images obtained with 6.3 mA were closest to the real measurements. CONCLUSION: On the basis of this study of dried skulls using CBCT, it was determined that image quality degradation was not significantly improved when the milliamperage setting was increased above 6.3 mA, whereas a milliamperage level below 6.3 mA resulted in degradation of the image quality. Therefore, significant dose reduction can be achieved with diagnostically satisfactory image quality on CBCT exams for implant planning by reducing the milliamperage setting.