CBCT-based volume of simulated root resorption - influence of FOV and voxel size.

AIM: To examine the influence of the field of view (FOV) and voxel size on the measurement of the volume of simulated internal root resorption (IRR) lesions through cone-beam computed tomography (CBCT). METHODOLOGY: Eleven single-rooted teeth with IRR simulated by acid demineralization were studied. CBCT images were acquired using large FOV (voxel sizes of 0.200, 0.250 and 0.300 mm) and limited FOV (voxel sizes of 0.076, 0.100 and 0.200 mm). The IRR volumes were calculated using the Dolphin(®) software. Volumetric measurements were validated using IRR silicone putty casts. The analysis of variance (anova) for randomized block design complemented with the Tukey's test was employed. RESULTS: IRR volumes obtained using voxel sizes of 0.200 and 0.250 mm were similar (P > 0.05). However, both these values were significantly different from that obtained using the 0.300-mm voxel (P < 0.05). There was no significant difference between IRR volumes measured through voxel sizes of 0.076 and 0.100 mm (P > 0.05), but both differed significantly from that obtained through the 0.200-mm voxel (P < 0.05). There was no significant difference between the volumetric measurements of the 0.200-mm voxel images of the restricted and large FOV protocols. The mean volumes of the silicone casts were smaller than those calculated using a 0.200-mm voxel, but were similar to those obtained using voxel sizes of 0.076 and 0.300 mm. CONCLUSIONS: Despite the FOV protocol, voxel size can influence measurement of simulated IRR volumes. The importance of standardization of CBCT image acquisition protocols is emphasized, especially during follow-up of an IRR lesion, to prevent misinterpretation of its extent, which can create a bias in clinical decisions.

Evaluation of a digital learning object (DLO) to support the learning process in radiographic dental diagnosis.

AIMS: Studies have shown that inappropriate therapeutic strategies may be adopted if crown and root changes are misdiagnosed, potentially leading to undesirable consequences. Therefore, the aim of this study was to evaluate a digital learning object, developed to improve skills in diagnosing radiographic dental changes. MATERIALS AND METHODS: The object was developed using the Visual Basic Application (VBA) software and evaluated by 62 undergraduate students (male: 24 and female: 38) taking an imaging diagnosis course. Participants were divided in two groups: test group, which used the object and control group, which attended conventional classes. After 3 weeks, students answered a 10-question test and took a practice test to diagnose 20 changes in periapical radiographs. RESULTS: The results show that test group performed better that control group in both tests, with statistically significant difference (P = 0.004 and 0.003, respectively). In overall, female students were better than male students. Specific aspects of object usability were assessed using a structured questionnaire based on the System Usability Scale (SUS), with a score of 90.5 and 81.6 by male and female students, respectively. CONCLUSIONS: The results obtained in this study suggest that students who used the DLO performed better than those who used conventional methods. This suggests that the DLO may be a useful teaching tool for dentistry undergraduates, on distance learning courses and as a complementary tool in face-to-face teaching.

Prevalence and distribution of dental anomalies in a paediatric population based on panoramic radiographs analysis.

AIM: To evaluate the frequency and distribution of dental anomalies (DA) in a paediatric population. MATERIALS AND METHODS: Panoramic digital radiographs of children between 6 and 12 years old performed at a reference centre for radiographic exams were accessed. Two calibrated examiners evaluated the radiographs. The association between variables and outcomes was assessed using non-parametric tests. The significance level was set at 5%. RESULTS: Five hundred and twelve individuals were included and 61.3% presented at least one DA. The mean age of patients with DA (9.35±1.60) was significantly higher compared to patients with no anomalies (7.90±1.58). Patients with supernumerary tooth, however, were significantly younger. The most frequent DA were permanent tooth radicular dilacerations (38.1%), permanent tooth agenesis (29.3%), supernumerary tooth (6.4%) and impacted tooth (6.4%). Anterior teeth and female patients were more affected by radicular dilacerations. Dental agenesis was more frequent in the third molars followed by the upper lateral incisor. CONCLUSION: DA are quite frequent in the paediatric population and the most common DA observed herein could only be identified through imaging exams. The most appropriate timing to perform an investigation for the detection of dental anomalies appears to be between 9 and 10 years old.

Prevalence and clinical aspects of respiratory syncytial virus A and B groups in children seen at Hospital de Clínicas of Uberlândia, MG, Brazil.

Respiratory syncytial virus (RSV) is well recognized as the most important pathogen causing acute respiratory disease in infants and young children, mainly in the form of bronchiolitis and pneumonia. Two major antigenic groups, A and B, have been identified; however, there is disagreement about the severity of the diseases caused by these two types. This study investigated a possible association between RSV groups and severity of disease. Reverse transcription-polymerase chain reaction was used to characterize 128 RSV nasopharyngeal specimens from children less than five years old experiencing acute respiratory disease. A total of 82 of 128 samples (64.1%) could be typed, and, of these, 78% were group A, and 22% were group B. Severity was measured by clinical evaluation associated with demographic factors: for RSV A-infected patients, 53.1% were hospitalized, whereas for RSV B patients, 27.8% were hospitalized (p = 0.07). Around 35.0% of the patients presented risk factors for severity (e.g., prematurity). For those without risk factors, the hospitalization occurred in 47.6% of patients infected with RSV A and in 18.2% infected with RSV B. There was a trend for RSV B infections to be milder than those of RSV A. Even though RSV A-infected patients, including cases without underlying condition and prematurity, were more likely to require hospitalization than those infected by RSV B, the disease severity could not to be attributed to the RSV groups.

Comparative study between conventional and cone beam CT-synthesized half and total skull cephalograms.

OBJECTIVES: The aim of this study was to compare cephalometric measurements obtained from conventional cephalograms with total and half-skull synthesized cone beam CT (CBCT) cephalograms. METHODS: Cephalometric analyses of 30 clinically symmetric patients were conducted by a calibrated examiner on conventional and CBCT-synthesized cephalograms (total, right and left). Reproducibility was investigated using the intraclass correlation coefficient (ICC). The Bland-Altman analysis was used to assess the agreement of the measurements from each factor obtained by conventional, total, right and left CBCT-synthesized cephalograms. RESULTS: The ICC was above 0.9 for most of the 40 cephalometric factors analysed, revealing similar levels of reproducibility. When the measurements obtained from conventional and CBCT-synthesized cephalograms were compared, the Bland-Altman analysis showed a strong agreement between them. CONCLUSIONS: Half-skull CBCT-synthesized cephalograms offer the same diagnostic performance and equivalent reproducibility in terms of cephalometric analysis as observed in conventional and total CBCT-synthesized cephalograms.

Evaluation of the reproducibility in the interpretation of magnetic resonance images of the temporomandibular joint.

OBJECTIVES: The aim was to determine the intra- and interexaminer reproducibility in the interpretation of MRI of the temporomandibular joint among independent observers, with respect to six specific articular characteristics, and to discover which of these had greater and lesser agreement. METHODS: 30 magnetic resonance examinations of temporomandibular joints of adults were independently interpreted by 9 experienced and trained observers at 2 different times. Observers were divided into three groups according to their specialties: surgeon dentists specialized in temporomandibular dysfunction and orofacial pain, surgeon dentists specialized in radiology and medical doctors specialized in radiology. The reproducibility analysis was carried out using Cohen's kappa coefficient. RESULTS: The interexaminer reproducibility ranged from slight to fair. The intraexaminer reproducibility ranged from slight to no agreement. In the interexaminer evaluation, anterior disc displacement without reduction presented greater agreement, whereas change in condylar head shape showed the poorest agreement. In the intraexaminer evaluation, anterior disc displacement without reduction presented slight agreement, whereas, for the other characteristics, no agreement was observed. CONCLUSION: Examiners do not demonstrate reproducibility in the interpretation of MRI of temporomandibular joints. Therefore, more efforts are necessary with respect to understanding the changes that may be detected in these images in terms of diagnosis and appropriate treatment approaches.

Influence of a programme of professional calibration in the variability of landmark identification using cone beam computed tomography-synthesized and conventional radiographic cephalograms.

OBJECTIVES: The validity of any measurement obtained through a cephalogram largely depends on the reproducibility of the cephalometric landmarks. The purpose of this study is to evaluate the influence of a programme of professional calibration (PPC) on the variability of landmark identification comparing conventional radiographs and cone beam CT (CBCT)-synthesized cephalograms. METHODS: 5 graduate students in oral radiology identified 20 cephalometric landmarks from cephalograms generated from conventional radiographs (RADs), Ray-Sum CBCT-synthesized cephalograms (CBTs) and half-skull CBT (HSTs) from 10 patients. After a period of reinforcement on instruction and calibration with inter- and intraexaminer assessment of reproducibility (intraclass coefficient correlation scores > 0.75) for RADs, CBTs and HSTs obtained from 5 different patients, observers were asked to repeat the analysis of the first 10 patients under the same circumstances. Values in millimetres represented each landmark in a table of Cartesian co-ordinates (x- and y-axes). RESULTS: ANOVA showed significant reduction in variability levels after the PPC, and there were no differences among the methods of image acquisition. Repeated measures ANOVA indicated that the PPC accounted for reduction in variability levels in 14 of 20 landmarks. CONCLUSIONS: The results suggest that a PPC has more influence than the type of image acquisition on variability of landmark identification based on two-dimensional cephalometric analysis. Cephalograms obtained from RAD or CBCT can be considered equivalent for clinical and experimental applications.

Diagnostic ability of computed tomography to evaluate external root resorption in vitro.

OBJECTIVES: The aim of this study was to evaluate the diagnostic ability of CT to detect simulated external root resorption defects. METHODS: External root resorption defects of different sizes and in different locations were simulated in 59 human mandibular incisors. Cavities simulating root resorption defects of 0.6 mm, 1.2 mm, or 1.8 mm in diameter and 0.3 mm, 0.6 mm, or 0.9 mm in depth (small, medium and large defects) were drilled in the cervical, middle and apical thirds of buccal surfaces. Axial CT was used to obtain cross-sectional images of the teeth, and 177 root thirds were assessed by a blinded observer. RESULTS: Of the 131 cavities, 117 were detected (89%). 32 of the 44 (72.72%) cavities located in the apical third were identified. A statistically significant difference (P<0.01) was found between the sizes of defects examined in the apical third. CONCLUSIONS: The evaluation of CT diagnostic ability revealed high sensitivity and excellent specificity. However, small cavities located in the apical third were more difficult to detect than all other cavities.

Respiratory viruses in children younger than five years old with acute respiratory disease from 2001 to 2004 in Uberlândia, MG, Brazil.

The main viruses involved in acute respiratory diseases among children are: respiratory syncytial virus (RSV), influenzavirus (FLU), parainfluenzavirus (PIV), adenovirus (AdV), human rhinovirus (HRV), and the human metapneumovirus (hMPV). The purpose of the present study was to identify respiratory viruses that affected children younger than five years old in Uberlândia, Midwestern Brazil. Nasopharyngeal aspirates from 379 children attended at Hospital de Clínicas (HC/UFU), from 2001 to 2004, with acute respiratory disease, were collected and tested by immunofluorescence assay (IFA) to detect RSV, FLU A and B, PIV 1, 2, and 3 and AdV, and RT-PCR to detect HRV. RSV was detected in 26.4% (100/379) of samples, FLU A and B in 9.5% (36/379), PIV 1, 2 and 3 in 6.3% (24/379) and AdV in 3.7% (14/379). HRV were detected in 29.6% (112/379) of the negative and indeterminate samples tested by IFI. RSV, particularly among children less than six months of life, and HRV cases showed highest incidence. Negative samples by both IFA and RT-PCR might reflect the presence of other pathogens, such as hMPV, coronavirus, and bacteria. Laboratorial diagnosis constituted an essential instrument to determine the incidence of the most common viruses in respiratory infections among children in this region.

Prevalence and clinical aspects of respiratory syncytial virus A and B groups in children seen at Hospital de Clínicas of Uberlândia, MG, Brazil

Respiratory syncytial virus (RSV) is well recognized as the most important pathogen causing acute respiratory disease in infants and young children, mainly in the form of bronchiolitis and pneumonia. Two major antigenic groups, A and B, have been identified; however, there is disagreement about the severity of the diseases caused by these two types. This study investigated a possible association between RSV groups and severity of disease. Reverse transcription-polymerase chain reaction was used to characterize 128 RSV nasopharyngeal specimens from children less than five years old experiencing acute respiratory disease. A total of 82 of 128 samples (64.1 percent) could be typed, and, of these, 78 percent were group A, and 22 percent were group B. Severity was measured by clinical evaluation associated with demographic factors: for RSV A-infected patients, 53.1 percent were hospitalized, whereas for RSV B patients, 27.8 percent were hospitalized (p = 0.07). Around 35.0 percent of the patients presented risk factors for severity (e.g., prematurity). For those without risk factors, the hospitalization occurred in 47.6 percent of patients infected with RSV A and in 18.2 percent infected with RSV B. There was a trend for RSV B infections to be milder than those of RSV A. Even though RSV A-infected patients, including cases without underlying condition and prematurity, were more likely to require hospitalization than those infected by RSV B, the disease severity could not to be attributed to the RSV groups.