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.

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.

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.