Development of a correction coefficient for radiographic evaluation of the alveolar bone crest: a pilot study.

OBJECTIVES: To analyze the differences in cusp height on radiographs, establishing proportional relationships between cusp and alveolar bone crest (ABC) measurements. The goal of this study was to develop a correction coefficient by considering this proportion. MATERIALS AND METHODS: Twenty-one artificial teeth, molars and premolars, and bovine ribs were used. Interproximal radiographs were taken with the aid of a positioner. The vertical angles used were: 0°, + 5°, and + 10°, and processed using three spatial resolutions measured in line pairs per mm (lp/mm): 20, 25 and 40. The Perio filter was applied to each image, in addition to the original one. Combinations of angle, resolution, and filter were made. Eighteen images were analyzed by three specialists, resulting in 252 measurements for each evaluator, totaling 756 measurements. RESULTS: The overall variability of the measurements can be explained mainly by the variation in tooth anatomy. The 0° 25 lp/mm Perio filter method was the closest one to the actual clinical scenario for both cusps and ABC. The correction factor managed to explain 71.45% of the errors. CONCLUSIONS: The variation in vertical angulation interferes with cusp and ABC measurements, and the angulation at 0º and spatial resolution of 25 lp/mm showed better results. The use of correction coefficients allowed approaching actual measurement values. CLINICAL RELEVANCE: More accurate ABC height measurements are essential even in radiographic exams that do not meet the standard of excellence because the need to repeat radiographic exams is then eliminated.

Impact of CBCT acquisition protocols and artifact reduction filters on diagnosing vertical root fractures.

AIM: To evaluate the impact of acquisition protocols and artifact reduction filters in cone beam computed tomography on diagnosing vertical root fractures in endodontically treated teeth with and without intraradicular posts. MATERIALS AND METHODS: We analyzed 480 tomographic images acquired from two J. Morita scanners (0.125- and 0.08-mm voxel sizes protocols), with application of a blooming artifact reduction filter. Three evaluators assessed these images for root fractures using a 5-point Likert scale. Diagnostic accuracy between filters and protocols was determined using generalized linear models with binomial distribution for the outcome, considering protocol, filter, and dental status. Sensitivity, specificity, positive predictive value, and negative predictive value were also estimated for the filters and protocols. RESULTS: The 0.08-mm voxel size protocol demonstrated a significantly higher percentage of accurate diagnosis compared to the 0.125-mm protocol (p = .001). No statistically significant differences (p ≥ .087) were observed for filter application, interaction between protocol and filter, or dental status. Accuracy, sensitivity, and specificity values were respectively: .93, .87, 1.00 (protocol 1); .99, .99, .99 (protocol 2); .98, .96, .99 (no filter); .95, .90, 1.00 (with filter). CONCLUSION: The new findings found for the two J Morita scanners used in our study were that images acquired using the voxel size of 0.08 mm showed an improvement in the diagnosis of root fractures and the filters in these devices have no relevance significant for the diagnosis.

Comparative study of cranial measurements between sexes from Brazil and The Netherlands: A cone-beam computed tomography study.

The objective of this study was to better understand human variation by comparing cone-beam computed tomography-based cranial measurements between both sexes of individuals from two distinct populations: Brazilian and Dutch. Cone-beam computed tomography volumes of 311 patients between 20 and 60 years from Brazil and The Netherlands were selected. Two radiologists performed 16 linear measurements in the maxillary sinuses and mandibular canal. Kruskall-Wallis test compared measurements of the two cranial structures between male and female for the two populations and four age ranges (20-30, 31-40, 41-50, 51-60). Mann-Whitney test compared individual measurements obtained from the cranial structures between male and female for each population, and between both populations for both sexes. Intra- and inter-observer reliability was assessed by intraclass correlation test (α = 0.05). No significant differences were found in the linear measurements among the experimental groups including sex, population and age group for both cranial structures (p > 0.05). Most of the cranial linear measurements were significantly higher for male than those for female irrespective of the population (p ≤ 0.05). When the populations were compared regardless of sex, Brazilians presented four significantly higher measurements, and Dutch presented seven significantly higher measurements (p ≤ 0.05). The assessed cranial structures did not differ between Brazilian and Dutch populations for both sexes and four age ranges. Multiple linear measurements differed between both populations with a predominance of larger dimensions for the Dutch population.

The imaging role for diagnosis of idiopathic osteosclerosis: a retrospective approach based on records of 33,550 cases.

OBJECTIVE: The study aimed to describe the diagnostic imaging features of idiopathic osteosclerosis (IO) to aid in differential diagnosis of similar dentomaxillomandibular conditions. MATERIALS AND METHODS: An archive of 550 dentomaxillofacial radiographic (panoramic radiography (PR) and cone beam computed tomography (CBCT)) images and 33,000 histopathological records were reviewed to identify IO cases. Chi-square, Student's t test, and ANOVA tests, with a significance of p < 0.05, were applied for comparative analysis. In addition, we analyzed various studies to present a short review. RESULTS: After meticulous observation, 36 images of 34 patients revealed 60 IO lesions in 31 PR and 5 CBCT. Sex, age group, anatomical site, shape, regularity, and root relationship showed statistical significance: sex and age group (p = 0.046), sex and IO regularity (p = 0.007), age group and IO regularity (p = 0.014), anatomical site and IO shape (p = 0.010), anatomical site and IO regularity (p = 0.003), and IO shape and IO regularity (p = 0.002). We presented a short review from 26 articles, including retrospective, cross-sectional, and longitudinal studies, documenting 2307 patients with 2435 IO lesions from 51,160 imagiological examinations. CONCLUSIONS: A radiographic diagnostic profile of IO may guide the clinical practitioners in differentiating an incidental radiopacity. PR is a preliminary examination, with CBCT facilitating the IO diagnosis. CLINICAL RELEVANCE: Knowledge of imaging characteristics variability of idiopathic osteosclerosis is crucial for accurate diagnosis process when incidental radiopacities are found in the panoramic radiographs, thus avoiding unnecessary biopsies. CBCT scans facilitate the interpretation of idiopathic osteosclerosis overlapping the mandibular canal.

Surgical and non-surgical debridement for the treatment of peri-implantitis: a two-center 12-month randomized trial.

OBJECTIVES: To compare surgical (ST) and non-surgical (NST) debridement for the treatment of peri-implantitis in a two-center randomized trial. MATERIALS AND METHODS: Forty-five individuals with 63 implants with probing depth (PPD) ≥5mm, bleeding on probing (BOP), and radiographic bone loss ≥2mm were included. In the NST (30 implants), submucosal debridement was performed. In the ST (33 implants), a mucoperiosteal flap was raised and surfaces were decontaminated only by debridement as performed in NST. Clinical parameters and radiographs were compared at baseline and after 12 months. Means and standard errors were reported. RESULTS: PPD considering all implant sites reduced significantly in NST from 4.14±0.25 to 3.25±0.18mm. In ST, PPD also significantly changed (3.74±0.22 to 3.00±0.29mm). No significant differences were observed between the two groups. For deep sites (≥7mm), PPD was 7.82±0.20mm at baseline and reduced to 5.10±0.30mm in NST, while in ST group, it was 7.11±0.11mm and changed to 5.22±0.91mm (between-groups p value=0.51). BOP significantly reduced from ~60 to 35% of all sites in both groups, without significant differences between them. When sites with radiographic bone level ≥3mm at baseline were analyzed, there was a significant difference between groups in bone gain after 12 months in favor of ST (ST=0.78±0.30mm compared to NST=0.25mm±0.13; p=0.03). CONCLUSIONS: Surgical and non-surgical debridement for the treatment of peri-implantitis present similar clinical outcomes. Bone levels were better improved in ST than NST for sites with higher initial bone loss. CLINICAL RELEVANCE: The treatment of peri-implantitis is still a challenge in clinical practice, since less than half of affected implants achieve health after surgical or non-surgical debridement. Considering the lack of clinically relevant differences between these two treatments, non-surgical debridement should be considered the first therapeutic choice for peri-implantitis, mainly mild to moderate cases.

Systemic sequelae and craniofacial development in survivors of pediatric rhabdomyosarcoma.

INTRODUCTION: The aim of this study was to evaluate the systemic sequelae, as well as the dental and craniofacial development, of patients with rhabdomyosarcoma in relation to the treatment received and clinical-pathological variables. MATERIALS AND METHODS: A retrospective cross-sectional study was performed. All individuals diagnosed with RMS between 1990 and 2022 were considered eligible. Cases who survived the primary tumor were included. Data were collected from medical records, and patients were called for clinical and radiographic examinations. RESULTS: Thirty-eight patients were assessed, with a mean disease-free survival of 216.68 months (±84.99). The primary location of the tumor was mainly the head and neck region (57.9 %). All patients received chemotherapy, and 30 (78.9 %) also underwent radiotherapy. The most frequently observed sequela was sensory impairment, which was significantly associated with tumors in the head and neck (p < 0.05), as well as with the use of radiotherapy (p = 0.034). Root formation failure was observed in 60 % of cases, microdontia in 50 %, and delayed tooth eruption in 40 %. A convex profile was predominant (80 %), along with maxillary (50 %) and mandibular (80 %) retrusion and a skeletal class II diagnosis (60 %). CONCLUSIONS: Late systemic, dental, and craniofacial developmental sequelae are observed in pediatric rhabdomyosarcoma survivors, especially in patients who underwent radiotherapy in the head and neck region. Younger individuals at the time of treatment are at greater risk of late sequelae.

The interference of digital radiographic image acquisition and processing protocols in the diagnosis of incipient enamel carious lesions.

Background: This study aims to evaluate the diagnosis of proximal carious lesions through different parameters of execution and visualization of the images. Material and Methods: Proximal carious lesions were artificially induced in human teeth three different times (10, 20, and 30 hours) by in vitro demineralization. The teeth were radiographed with the Dürr digital system using three exposure times (0.10, 0.16, and 0.20s) and three different resolutions in the scanning of the phosphor plates (20-, 25- and 40-line pairs). After acquiring the images, they were submitted to VistaScan Fine, Caries 1, and Caries 2 software filters. Three radiologists analyzed the images in JPEG format. Results: The Pearson's chi-square test showed an association between longer demineralization time and the presence of injury according to the professional's classification. There was no statistically significant association among the other parameters, exposure time, resolution, and use of filters and the presence of a lesion. All parameters showed a greater sensitivity than specificity. The exposure time of 0.2s showed better accuracy, the resolutions 25 and 40lp showed equal results and better than 20lp and the Fine filter obtained better values than the Caries 1 and 2 filters. Conclusions: Despite the variation of parameters, exposure time, resolution, and use of filters, there were no statistically significant differences. For better diagnostic accuracy, it is recommended to use 0.2s of exposure time and a Fine filter, and scan the phosphor plates with 25lp. Key words:Orbital fracture, Etiology, Orbital trauma, Road traffic accidents, Trauma.

Impact of dental imaging on pregnant women and recommendations for fetal radiation safety: A systematic review.

Purpose: This study was conducted to investigate the safety of dental imaging in pregnant women with respect to fetal health. Materials and Methods: Searches were conducted of the PubMed, Scopus, and Web of Science databases in May 2023. The inclusion criteria encompassed cross-sectional and longitudinal studies that focused on the analysis of diagnostic dental imaging in pregnant women, as well as studies utilizing phantoms to simulate imaging examinations. The exclusion criteria consisted of reviews, letters to the editor, book chapters, and abstracts from scientific conferences and seminars. Results: A total of 3,913 articles were identified. Based on a review of the titles and abstracts, 3,892 articles were excluded, leaving 21 articles remaining for full-text review. Of these, 18 were excluded, and 4 additional articles were included as cross-references. Ultimately, 7 articles underwent quantitative-qualitative analysis. Three retrospective studies were focused on pregnant women who underwent dental imaging procedures. The remaining 4 studies utilized female phantoms to simulate imaging examinations and represent the radiation doses absorbed by the uterus or thyroid. Conclusion: Few dental radiology studies have been conducted to determine the safe radiation threshold for pregnant women. Additionally, the reviewed articles did not provide numbers of dental examinations, by type, corresponding to this dose. Dental imaging examinations of pregnant women should not be restricted if clinically indicated. Ultimately, practitioners must be able to justify the examination and should adhere to the "as low as diagnostically acceptable, being indication-oriented and patient-specific" (ALADAIP) principle of radioprotection.

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.

Can CBCT change the level of confidence of oral maxillofacial surgeons in mandibular third molar management?

This study analyzed the impact of CBCT on the level of confidence in diagnostic and treatment thinking in mandibular lower molar (M3M) clinical management. Thirty cases for which panoramic radiographs and CBTC images were available were selected and classified according to radiologic signs indicating the proximity of the M3M to the mandibular canal (interruption of the radiopaque borders of the canal of the mandibular canal wall, darkening of the roots, and diversion or narrowing of the canal, n = 10 for each classification). Twelve oral and maxillofacial surgeons (OMS) contributed to this study by answering two questionnaires. The first questionnaire contained a clinical description of the case and a panoramic radiograph. After 30 days, a second questionnaire with the same clinical illustrations and tomographic multiplanar reconstruction images was administered. Both questionnaires asked specialists to rate diagnostic confidence, the surgical complexity, chosen treatment, and surgical confidence. In approximately 40% of answers, CBCT images had a positive impact on ratings of diagnostic confidence and treatment thinking confidence, and in 24.4%, they increased the surgical complexity score. There was no change in the treatment plan following the use of CBCT, but the CBCT examination was a determining factor for diagnosis and treatment planning in 72.8% of the answers CBCT improved the confidence level in diagnostic and treatment thinking of the M3M management while also increasing the perceived level of surgical complexity. The findings of this study support the need to consider using CBCT in diagnosis and treatment planning for M3Ms with radiographic signs such as darkening of the roots, interruption of the radiopaque borders of the mandibular canal, or deviation of the mandibular canal and narrowing of the roots.

Impact of dentists and equipment in the performing dental imaging examinations: a longitudinal analysis.

In this study, we aimed to identify factors associated with performing dental imaging examinations in public health services. Brazilian data at the municipal level (n = 5,564) in two time periods, P0 (2005-2007) and P1 (2014-2016), were collated from health information systems. The increase in the municipal rates of intraoral and extraoral radiographic imaging procedures was the outcome. Changes in the use of clinical procedures and the rates of dentists and equipment were the main predictors. Multiple logistic regression analysis was performed to estimate the adjusted odds ratio (OR). Approximately 35.3% of the Brazilian municipalities increased the dental radiography equipment rate, 9.9% increased the fan-beam computed tomography (CT) equipment rate, and 5.9% increased the magnetic resonance imaging (MRI) equipment rate. In addition, 31.8% increased the periapical/interproximal radiography rate, 10.5% increased the CT rate, and 4.4% increased the MRI rate. Increases in the dental radiography, CT, and MRI rates were associated with higher chances of periapical/interproximal images (OR = 1.90, p < 0.01), face and neck images (OR =1 5.3, p < 0.01), and MR images (OR = 18.1, p < 0.01), respectively. Municipalities that increased the rates of endodontists increased the rates of periapical/interproximal (OR = 2.50, p < 0.01) and occlusal (OR = 1.60, p < 0.01) imaging procedures, and those that increased the rates of radiologists also increased the rates of occlusal (OR = 2.00, p < 0.01) and panoramic (OR = 1.70, p < 0.01) imaging procedures. The implementation of a secondary dental care center, Centro de Especialidades Odontológicas (CEO) was associated with an increase in the chances of performing periapical/interproximal and panoramic radiographic procedures in 1.5 and occlusal radiographic examinations in 2.0. The rates of dentists, equipment, specialized dental centers, and specific dental procedures were associated with the increased use of imaging procedures in dentistry in the Brazilian public health system.

Validation and comparison of volume measurements using 1 multidetector computed tomography and 5 cone-beam computed tomography protocols: An in vitro study.

Purpose: The purpose of this study was to compare volume measurements obtained using 2 image software packages on Digital Imaging and Communications in Medicine (DICOM) images acquired from 1 multidetector computed tomography and 5 cone-beam computed tomography devices, using different protocols for physical volume measurements. Materials and Methods: Four pieces of bovine leg were prepared. Marrow was removed from 3 pieces, leaving cortical bone exposed. The resulting space of 1 piece was filled with water, another was filled with propylene glycol, and the third was left unfilled. The marrow in the fourth sample was left fully intact. Volume measurements were obtained after importing DICOM images into the Dolphin Imaging 11.95 and ITK-SNAP software programs. Data were analyzed using 3-way analysis of variance with a generalized linear model to determine the effects of voxel size, software, and content on percentage mean volume differences between tomographic protocols. A significance level of 0.05 was used. Results: The intraclass correlation coefficients for intraobserver and interobserver reliability were, respectively, 0.915 and 0.764 for the Dolphin software and 0.894 and 0.766 for the ITK-SNAP software. Three sources of statistically significant variation were identified: the interaction between software and content (P=0.001), the main effect of content (P=0.014), and the main effect of software (P=0.001). Voxel size was not associated with statistically significant differences in volume measurements. Conclusion: Both content and software influenced the accuracy of volume measurements, especially when the content had gray values similar to those of the adjacent tissues.

[Dental imaging procedures in the Unified Health System and the expansion of secondary care: series between 2000-2016]. / Procedimentos de imagem em Odontologia no Sistema Único de Saúde e a expansão da atenção secundária: série entre 2000-2016.

The scope of this paper was to analyze the time series of dental procedures performed between 2000 and 2016 in the Brazilian Unified Health System (SUS). The data were obtained from the Outpatient Information System of the SUS (SIA-SUS). The influence of the 2004 National Oral Health Policy of Ordinance No. 600/2006 (which instituted the financing of Dental Specialty Centers - CEOs), and Ordinance No. 1,234/2013 (Financial incentive for the Program for Enhancement of Quality and Access - PMAQ-CEO) were analyzed. Descriptive analyses of the initial and final years of the time series were presented, assessing trends and seasonality in seven types of imaging procedures. The time series of rates of periapical/bitewing radiographic exams revealed a trend of moderate increase and was the only area in which the impact of the financial implementation policy of the CEOs was observed, though not of the PMAQ-CEO. Extraoral imaging exams, such as panoramic radiography, facial CT/TMJ and TMJ MRI revealed a strong upward trend, despite the very low rates. The conclusion reached is that between 2000 and 2016, the policy of expansion of secondary care increased the use of periapical/bitewing imaging exams.

O objetivo foi analisar a série temporal de procedimentos de imagem em Odontologia realizados entre os anos de 2000 e 2016 no Sistema Único de Saúde (SUS). Os dados foram obtidos do Sistema de Informações Ambulatoriais (SIA-SUS). Foram analisadas a influência da Política Nacional de Saúde Bucal de 2004, da Portaria nº 600/2006 (institui o financiamento dos Centros de Especialidades Odontológicas - CEOs) e Portaria nº 1.234/2013 (Incentivo financeiro do Programa de Melhoria do Acesso e da Qualidade - PMAQ-CEO). Apresentou-se análises descritivas dos anos inicial e final da série temporal, avaliando tendências e sazonalidade em sete tipos de procedimentos. A série temporal das taxas de exames radiográficos periapicais/interproximais demonstrou tendência de aumento moderado e foi a única em que se observou o impacto da política de implementação financeira dos CEOs, mas não do PMAQ-CEO. Os exames extraorais como: radiografia panorâmica, Tomografia Computadorizada (TC) da face/Articulação Temporomandibular (ATM) e Ressonância Magnética (RM) da ATM possuem forte tendência de aumento apesar das taxas serem muito baixas. Conclui-se que entre os anos 2000 e 2016, a política de expansão da atenção secundária, aumentou o uso de exames de imagem periapical/interproximal.

Benefits of using a photostimulable phosphor plate protective device.

OBJECTIVES: To develop and test a protective device (PD) to increase the resistance of photostimulable storage phosphor (PSP) plate to compressive load, and assess the resulting image quality. METHODS: Two prototypes, polyvinylchloride sheets of 0.3 mm and 0.7 mm each, were developed for PSP plate size 2. The resistance to compressive load was tested using eight new PSPs divided into four test groups: (1) PSP, (2) PSP and paperboard protector, (3) PSP and 0.3 mm PD, and (4) PSP and 0.7 mm PD. The resulting images were analyzed by three oral radiologists, based on the consensus for image artifacts. Additionally, the objective image quality test was performed with four new PSPs, using an 8-step wedge aluminum scale. The mean gray values and standard deviation were measured in a total of 240 images, and the data were analyzed using analysis of variance with Bonferroni post-hoc test. RESULTS: Artifacts were seen in the PSP control group starting at 40 n, and at 150 n, 175 n and 300 n in 0.3 mm PD, paperboard protector and 0.7 mm PD, respectively. Although there was no statistical difference among groups, there were differences between exposure times (0.06-0.25 s, 0.06-0.40 s, and 0.10-0.40 s). Scanning resolution of 20 lp/mm showed higher mean gray value than 25 and 40 lp/mm (p < 0.05). CONCLUSION: The developed PDs improved the PSP resistance to compressive forces, with low interference on the pixel gray values, regardless of exposure time and spatial resolution. Nevertheless, the 0.7 mm PD could withstand the maximum compressive load.

Association between internal carotid artery calcifications detected as incidental findings and clinical characteristics associated with atherosclerosis: A dental volumetric tomography study.

PURPOSE: To evaluate the presence of calcifications in the internal carotid artery (ICA) in cone-beam computed tomography (CBCT), and to verify the association of these findings with sex, age, dental condition, and risk factors associated with vascular disorders. METHODS: The CBCT scans used in this study were obtained from the database of a private dental clinic requested for the planning of rehabilitation with dental implants. The selection criteria were patients aged 40 years and above. Out of a pool of 1176 CBCT examinations, a total of 284 scans of adult patients were evaluated by two blinded observers. Data were collected from patients' medical records. RESULTS: ICA calcifications were present in 63.0% of the examinations. Most calcifications were in the intracranial pathway (166). Despite being present in a smaller number 57 (C1), extracranial calcifications were more severe. Spearman's ρ coefficients (rS) indicated that the number of missing teeth was directly associated with the presence of calcifications (p = 0.042) and severity (p = 0.020). The age variable also had a direct relationship with the presence of calcifications (p ≤ 0.0001), increasing its frequency and severity over the years. In addition, hypertension (p = 0.036) and use of antihypertensive drugs (p = 0.015) were directly associated. CONCLUSIONS: There is a high occurrence of ICA calcifications in CBCT as incidental findings in adult patients, and it is directly associated with age, number of missing teeth and hypertension.

Diagnostic efficacy of different cone beam computed tomography scanning protocols in the detection of chemically simulated external root resorption.

OBJECTIVES: The aim of this study was to evaluate the efficacy of different high-resolution cone beam computed tomography protocols in the diagnosis of chemically simulated external root resorption (ERR). STUDY DESIGN: ERR was simulated in 3 sizes by using an acid decalcification protocol in the cervical, middle, and apical thirds of 30 single-rooted premolars. Four scans of each tooth were acquired with different voxel sizes: 0.080, 0.085, 0.120, and 0.133 mm. The images were analyzed by 2 blinded evaluators for the presence of ERR. The evaluation of diagnostic performance was based on receiver operating characteristic (ROC) curve analysis. RESULTS: No statistically significant differences were found in the detection of ERR with regard to lesion sizes or the different root thirds. Areas under the ROC curve were 0.901, 0.892, 0.887, and 0.767 for voxel sizes of 0.080, 0.085, 0.120, and 0.133 mm, respectively. Voxel sizes of 0.080 and 0.085 mm presented significantly larger areas under the ROC curve compared with the voxel size of 0.133 mm. There were no statistically significant differences among the protocols with the use of voxel sizes of 0.080, 0.085, and 0.120 mm. CONCLUSIONS: Cone beam computed tomography examinations with higher-resolution protocols demonstrated better performance in the diagnosis of ERR. Further investigations using simulations that more closely resemble the actual ERR process are warranted.

Evaluation of the radiographic cephalometry learning process by a learning virtual object.

INTRODUCTION: Radiographic cephalometry is a complex area of study. The literature shows a lack of interobserver reproducibility in the definition and identification of cephalometric landmarks. The aim of this study was to test a learning virtual object (LVO) called ceph learning used in the teaching of radiographic cephalometry and to verify whether it improves performance of the landmarking process. METHODS: A total of 40 undergraduate students were divided into 2 groups. Group A was taught according to the conventional teaching method of theory and practical classes, and group B was taught with an LVO. The students' learning performance was tested by using a multiple-choice questionnaire that covered the knowledge and understanding of cephalometry and by the index of correct landmark identification. The Student t test was used to check statistical differences between the 2 groups. LVO usability was evaluated with a questionnaire based on the system usability scale. RESULTS: In the first posttest, the Student t test showed no significant differences (P >0.05). However, in the second posttest 15 days later, a decrease was observed in the scores of group A, with significant differences (P <0.05). Students approved the LVO usability aspects--effectiveness, efficiency, and satisfaction (82.45% +/- 6.78%). CONCLUSIONS: LVO was shown to be a useful and efficient tool in the learning process and might assist the learning of cephalometry.

Software system for calibrating examiners in cephalometric point identification.

INTRODUCTION: The literature has shown that subjective concepts lead to interobserver variations in the definitions and identifications of cephalometric landmarks. Observers must be trained and calibrated to conduct scientific research using cephalometric comparisons. In this study, we aimed to develop and test a computational model called Cyclops cephalometry in radiographic cephalometry training and calibration. METHODS: This system uses the concepts of evaluation process managers, examiners, and testers, thus affording uniformity in cephalometric evaluations. The system was tested with 5 orthodontists and 5 postgraduate students who located 28 landmarks in 10 lateral cephalometric radiographs before and after training. RESULTS: Before training, the Student t test showed significant differences (P <0.05) in accuracy between the orthodontists and the students (71.4% and 54.9%, respectively). However, considerable improvement in accuracy was observed after training in both groups (86.5% and 83%, respectively), without significant differences (P = 0.30) between groups. Users of the system agreed about its usability aspects such as effectiveness, efficiency, and satisfaction. CONCLUSIONS: This model was shown to be a useful and efficient tool in the calibration process, and might be helpful in various comparative cephalometric investigations.

Imaging Factors Impacting on Accuracy and Radiation Dose in 3D Printing.

OBJECTIVES: To compare reconstructed area and surface roughness of 3D models acquired using nine image acquisition protocols. Radiation dose was also compared among acquisition protocols. METHODS: A dry craniofacial specimen was scanned using three CT devices (a cone beam CT, a 16-channel fan beam CT, and a 64-channel fan beam CT), with three different acquisition protocols each. Nine 3D models were manufactured using polylactic acid. Surface roughness and reconstructed area were determined for each 3D model. The radiation dose during acquisitions was measured using lithium crystals. ANOVA was used to compare the data among the 3D models. Linear function optimization techniques based on stochastic variables were applied to identify the most suitable protocol for use. RESULTS: For surface roughness, statistically significant differences were observed among all 3D models and the specimen. For reconstructed area, CBCT and one CT-16 channel protocols originated 3D models statistically significant different from the specimen. Higher radiation doses were observed with fan beam CT acquisitions. CONCLUSIONS: All three CT devices were suitable for 3D printing when used at full resolution. The highest reconstruct area vs. radiation dose ratio was found for 64-channel CT devices.