Ambient light exposure of photostimulable phosphor plates: is there a safe limit for acceptable image quality?

OBJECTIVES: To subjectively assess radiographs obtained with photostimulable phosphor (PSP) plates exposed to clinical levels of ambient light prior to read-out to potentially set a safe limit for acceptable image quality. METHODS AND MATERIALS: Six dental regions of a dry human skull were X-rayed using PSP plates from VistaScan and Express under four exposure times: 0.1, 0.2, 0.32, and 0.4 s. Before read-out, the PSP plates were exposed to ambient light for 0, 5, 10, 30, 60, and 90 s. Six observers were asked to classify the 288 resulting radiographs as acceptable or unacceptable based on the identification of anatomical structures and global image quality. The number of answers classifying radiographs as unacceptable was used to calculate a rejection rate; a pairwise comparison for better image quality was further conducted among radiographs considered acceptable. Reproducibility was tested by having 25% of all experimental groups reassessed. RESULTS: Intra- and interobserver agreement ranged from 0.87 to 1.00 and from 0.81 to 0.92, respectively. Exposure of PSP plates to ambient light increased rejection rates mostly as of 10 s. In the pairwise comparison, subtle differences were observed between radiographs obtained with PSP plates not exposed and those exposed to ambient light for 5 s. CONCLUSIONS: Ambient light exposure of PSP plates impairs the image quality of radiographs. A safe limit of ambient light exposure of 5 s for VistaScan and Express should be considered. Ambient light exposure of PSP plates within safe limits can avoid retakes and reduce unnecessary patient exposure to X-rays.

How Does Ambient Light Affect the Image Quality of Phosphor Plate Digital Radiography? A Quantitative Analysis Using Contemporary Digital Radiographic Systems.

The aim of this study is to quantitatively evaluate the influence of the duration of ambient light exposure on the image quality of digital radiographs obtained with contemporary phosphor plate (PSP)-based systems. Radiographs of an aluminum step-wedge were obtained using VistaScan and Express systems at five X-ray exposure times: 0.10, 0.20, 0.32, 0.40, and 0.50 s; the resulting dose-area products were, respectively, 21.93, 43.87, 70.19, 87.75, and 109.6 mGycm2. Before PSP read-out, half of the sensitive surface of the PSP plates was exposed to ambient light for 5, 10, 30, 60, and 90 s. The effect of light exposure on brightness, contrast, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and image saturation was compared using ANOVA with the Tukey test (α = 0.05). Ambient light exposure increased brightness and contrast and reduced CNR and SNR in PSP-based radiographs of contemporary digital systems. At the longest X-ray exposure times, ambient light exposure reduced the dark saturation (mean gray values ≤ 1) observed in Express. In conclusion, the negative effects of ambient light observed on the image quality of PSP-based radiographs are directly proportional to the duration of exposure. Clinicians should be aware of such harmful effects when handling and scanning PSP plates in bright environments.

Mapping of a multilayer panoramic radiography device.

OBJECTIVE: To map the shape, location, and thickness of the focal trough of a panoramic radiography device with a multilayer imaging program. METHODS: An acrylic plate (148 × 148 × 3 mm) containing 1156 holes distributed in a matrix of 34 × 34 rows was placed in the OP300 Maxio at the levels of the maxilla and mandible. 20 metal spheres (3.5 mm in diameter) were placed on the holes of the plate under 15 different arrangements and panoramic images were acquired for each arrangement at 66 kV, 8 mA, and an exposure time of 16 s. The resulting panoramic radiographs from the five image layers were exported, the horizontal and vertical dimensions of the metal spheres were measured in all images using the Image J software, and the magnification and distortion rates of the spheres were calculated. All metal spheres presenting a magnification rate lower than 30% in both vertical and horizontal dimensions and a distortion rate lower than 10% were considered to map the focal troughs of each of the five image layers. RESULTS: All panoramic image layers had a curved shape ranging from 39° to 51° for both dental arches and varied in position and thickness. The anterior region of maxilla was anteriorly displaced when compared to the anterior region of the mandible for all layers. Image layers are thicker at the level of the mandible than those at the level of the maxilla; also, inner layers were thinner and outer layers were thicker. CONCLUSION: All image layers in the studied panoramic radiography device had a curved shape and varied in position and thickness. The anterior region of maxilla was anteriorly displaced when compared to that of the mandible for all layers.

Radiographic Diagnosis of Simulated External Root Resorption in Multi-Rooted Teeth: The Influence of Spatial Resolution.

The aim of this study was to evaluate the influence of spatial resolution (line pairs per millimetre - lp/mm) on the diagnosis of simulated external root resorption (ERR) in multi-rooted teeth by using digital periapical radiography. Forty human mandibular molars (80 roots) were used. The roots were divided into the following groups (n = 10): control without root filling (WORF), control with root filling (WRF), small ERRWORF, small ERR-WRF, moderate ERR-WORF, moderate ERR-WRF, extensive ERR-WORF and extensive ERR-WRF. Four digital radiographs (phosphor storage plates - PSP system) were taken of each tooth in three angulations. The PSPs were scanned with 10, 20, 25 and 40 lp/mm. All images were assessed by three endodontists who used a five-point scale for presence and absence of ERR and classified its location (cervical, middle or apical third). ROC curves and one-way ANOVA were performed (p < 0.01). Diagnosis of ERR in nonroot-filled teeth showed higher values of sensitivity for 20 lp/mm and higher values of both specificity and accuracy for 40 lp/mm. In root-filled teeth, sensitivity and accuracy were higher for 25 lp/mm and spatial resolution had no influence on specificity. The best resolution for diagnosis of small and extensive ERR was 25 lp/mm, whereas for moderate ERR, it was 40 lp/mm. Cervical ERR was the most difficult to diagnose, regardless of the spatial resolution. Higher spatial resolutions have improved the radiographic diagnosis of simulated ERR in multi-rooted teeth and this should be considered when performing digital radiographs.

O objetivo deste estudo foi avaliar a influência do número de pares de linhas em radiografia intra-oral digital, na precisão da detecção de reabsorção radicular externa. Quarenta molares inferiores (n=80 raízes) foram submetidos ao preparo químico mecânico e em então, metade da amostra foi obturada. Em seguida, as raízes dos dentes foram aleatoriamente divididas de acordo com o tamanho da reabsorção radicular a ser simulada e com a presença e ausência de tratamento endodôntico. As RRE foram realizadas com brocas esféricas diamantadas de tamanhos 1/2, 1, 2. Executou-se radiografias digitais por meio do sistema de aquisição semidireto com a utilização de placas de fósforo fotoestimuladas (PSP). Em cada dente, incidências orto, mésio e distorradial foram repetidas quatro vezes, para que pudessem ser digitalizadas com resoluções de 10, 20, 25, 40 pl/mm. Após análise, verificou-se que dentes obturados apresentaram menores valores de sensibilidade com 10, 20 e 25 pl/mm e maiores valores de especificidade e acurácia para as mesmas resoluções. Dentes sem obturação registraram maiores valores de sensibilidade para resolução 20 e menor para 40; no entanto, a especificidade e a acurácia, foram maiores com 40 e menores em 10. Em RRE pequena, as resoluções 10 e 25 pl/mm foram respectivamente menos e mais acuradas; RRE média, foi maior com 40 pl/mm e RRE grandes foram melhores identificadas com 25. Correlacionando acertos no diagnóstico com localização das RRE, verificou-se que o terço cervical apresentou-se menos detectável. Concluiu-se que resolução espacial influenciou a detecção de RRE simuladas em radiografias periapicais digitais.

Radiographic Diagnosis of Simulated External Root Resorption in Multi-Rooted Teeth: The Influence of Spatial Resolution / Diagnóstico radiográfico de reabsorção externa simulada em dentes multiradiculares: influência da resolução especial

ABSTRACT The aim of this study was to evaluate the influence of spatial resolution (line pairs per millimetre - lp/mm) on the diagnosis of simulated external root resorption (ERR) in multirooted teeth by using digital periapical radiography. Forty human mandibular molars (80 roots) were used. The roots were divided into the following groups (n = 10): control without root filling (WORF), control with root filling (WRF), small ERRWORF, small ERRWRF, moderate ERRWORF, moderate ERRWRF, extensive ERRWORF and extensive ERRWRF. Four digital radiographs (phosphor storage plates - PSP system) were taken of each tooth in three angulations. The PSPs were scanned with 10, 20, 25 and 40 lp/mm. All images were assessed by three endodontists who used a fivepoint scale for presence and absence of ERR and classified its location (cervical, middle or apical third). ROC curves and oneway ANOVA were performed (p < 0.01). Diagnosis of ERR in nonrootfilled teeth showed higher values of sensitivity for 20 lp/mm and higher values of both specificity and accuracy for 40 lp/mm. In rootfilled teeth, sensitivity and accuracy were higher for 25 lp/mm and spatial resolution had no influence on specificity. The best resolution for diagnosis of small and extensive ERR was 25 lp/mm, whereas for moderate ERR, it was 40 lp/mm. Cervical ERR was the most difficult to diagnose, regardless of the spatial resolution. Higher spatial resolutions have improved the radiographic diagnosis of simulated ERR in multirooted teeth and this should be considered when performing digital radiographs.

RESUMO O objetivo deste estudo foi avaliar a influência do número de pares de linhas em radiografia intraoral digital, na precisão da detecção de reabsorção radicular externa. Quarenta molares inferiores (n=80 raízes) foram submetidos ao preparo químico mecânico e em então, metade da amostra foi obturada. Em seguida, as raízes dos dentes foram aleatoriamente divididas de acordo com o tamanho da reabsorção radicular a ser simulada e com a presença e ausência de tratamento endodôntico. As RRE foram realizadas com brocas esféricas diamantadas de tamanhos 1/2, 1, 2. Executouse radiografias digitais por meio do sistema de aquisição semidireto com a utilização de placas de fósforo fotoestimuladas (PSP). Em cada dente, incidências orto, mésio e distorradial foram repetidas quatro vezes, para que pudessem ser digitalizadas com resoluções de 10, 20, 25, 40 pl/mm. Após análise, verificouse que dentes obturados apresentaram menores valores de sensibilidade com 10, 20 e 25 pl/mm e maiores valores de especificidade e acurácia para as mesmas resoluções. Dentes sem obturação registraram maiores valores de sensibilidade para resolução 20 e menor para 40; no entanto, a especificidade e a acurácia, foram maiores com 40 e menores em 10. Em RRE pequena, as resoluções 10 e 25 pl/mm foram respecti vamente menos e mais acuradas; RRE média, foi maior com 40 pl/mm e RRE grandes foram melhores identificadas com 25. Correlacionando acertos no diagnóstico com localização das RRE, verificouse que o terço cervical apresentouse menos detectável. Concluiuse que resolução espacial influenciou a detecção de RRE simuladas em radiografias periapicais digitais.

Influência do tipo de compósito e tempo de exposição aos raios-x na produção de artefatos radiográficos em modelos de restauração classe II / Influence of the type of composite and time of exposure to x-rays on the production of radiographic artifacts in class II restoration models

Objetivo: Avaliar o efeito do tempo de exposição e do tipo de compósito na produção de artefato radiográfico na interface dente/material restaurador. Materiais e Métodos: Em 20 incisivos bovinos hígidos foram feitos preparos cavitários e restaurações classe II utilizando resinas compostas Filtek Bulk Fill One (gruo 1) e a Filtek Z350 (grupo 2). Em seguida, os dentes foram expostos para obtenção das radiografias digitais, variando o tempo de exposição em 0,07, 0,10, 0,14, 0,20 e 0,25s. As imagens foram avaliadas para investigação da presença de artefato através da análise do número de pixels modificado (QPXD) e do valor médio de cinza nas restaurações de classe II (MGVR), utilizando o software Image J (Instituto Nacional de Saúde, Bethesda, MD, EUA). Resultados: Observou-se a presença de artefato em toda amostra avaliada, independente de tipo de material restaurador e tempo de exposição empregado. Não se observou diferença estatisticamente significante na QPXD e nos MGVR entre as resinas utilizadas (ANOVA 2 fatores, p p>0,05). A análise do MGVR indicou que não houve diferenças estatisticamente significativas entre as resinas nem entre os tempos de exposição (p>0,05). Observou-se uma correlação entre a QPXD e o MGVR (r=0,29) para a resina Filtek Bulk Fill One. Conclusão: Foi identificado a presença de pixels alterados sobre a dentina na região da interface dente-restauração em todos os corpos de prova. A variação do tempo de exposição como também o tipo do compósito restaurador não influenciou no aumento ou diminuição do QPXD e nem tão pouco no MGVR. Contudo houve correlação entre o QPXD e o MGVR para a resina Filtek Bulk Fill One. Pesquisas adicionais são necessárias para determinar se o QPXD representa um artefato verdadeiro ou desajuste do material restaurador ou deficiência na aplicação sistema adesivo (AU).

Objective: To evaluate the effect of the exposure time and the type of composite in the production of radiographic artifact at the tooth / restorative interface. Materials and Methods: In 20 healthy bovine incisors, cavity preparations and class II restorations were made using composite resins Filtek Bulk Fill One (group 1) and Filtek Z350 (group 2). Then, the teeth were exposed to obtain digital radiographs, varying the exposure time by 0.07, 0.10, 0.14, 0.20 and 0.25s. The images were evaluated for investigation of the presence of artifact through the analysis of the modified number of pixels (QPXD) and the average gray value in class II (MGVR) restorations, using the Image J software (National Health Institute). Results: The presence of artifact was observed in all evaluated samples, regardless of the type of restorative material and the exposure time employed. There was no statistically significant difference in QPXD and MGVR between the resins used (ANOVA 2 factors, p p> 0.05). The MGVR analysis indicated that there were no statistically significant differences between resins or between exposure times (p> 0.05). There was a correlation between QPXD and MGVR (r = 0.29) for Filtek Bulk Fill One resin. Conclusion: The presence of altered pixels on dentin in the region of the tooth-restoration interface was identified in all specimens. The variation in the exposure time as well as the type of the restorative composite did not influence the increase or decrease of QPXD and neither in MGVR. However, there was a correlation between QPXD and MGVR for Filtek Bulk Fill One resin. Further research is needed to determine whether QPXD represents a true artifact or misfit of the restorative material or deficiency in the adhesive system application (AU).

Importância pericial na análise da radiopacidade de resinas compostas por meio de sistema radiográfico digital / Forensic importance in the analysis of composite radiopacity using digital radiograph system

Introdução: A análise da radiopacidade nos exames radiográficos é importante ao cirurgião-dentista não apenas para a diferenciação entre estruturas dentais e material restaurador, mas também para verificação de infiltrações marginais e do diagnóstico de cáries secundárias ou recorrentes. Além de sua importância clínica, a diferenciação de materiais restauradores por sua radiopacidade apresenta potencial no âmbito forense, uma vez que pode auxiliar no processo de identificação humana. Objetivo: Este estudo teve como objetivo avaliar a radiopacidade das resinas compostas fotopolimerizáveis Tetric N Ceram, Z100, Z250 e Z350 por meio de radiografia digital. Métodos: Foi realizado um estudo experimental in vitro com 16 corpos de prova medindo 2x4mm. Foi usada uma escala de alumínio com 9 degraus (com 1 mm de espessura cada) para comparação dos valores da escala dinâmica encontrados por meio das imagens digitais geradas no sistema digital radiográfico indireto. Foram feitas 12 leituras para cada resina avaliada e para cada um dos sete degraus da escala de alumínio em três datas diferentes. Para verificar qual dos degraus da escala de alumínio representaria os valores obtidos pelas resinas individualmente, os valores foram comparados com aqueles obtidos em cada degrau. Resultados: A resina Tetric mostrou maior similaridade com o degrau 1 da escala de alumínio, ou seja, o mais radiopaco. A resina Z100 apresentou valores próximos com o degrau 3. Os valores da resina Z250 apresentaram variabilidade entre os degraus 3 e 4, porém não mostrou correlação com os mesmos. A resina Z350 apresentou correlação muito boa, inversa e significativa com os degraus 3 e 4. Conclusão: Cada resina analisada apresentou características de radiopacidade singulares, que potencialmente viabilizam o auxilio a Odontologia Legal frente à necessidade de identificação humana. Em específico, a resina Tetric apresentou maior radiopacidade. Ainda assim, as resinas Z100, Z250 e Z350 apresentaram radiopacidade dentro dos padrões esperados (exigidos pela ISO 4049). Estudos futuros são necessários com outras resinas compostas para compreender melhor o potencial desta pesquisa para propósitos forenses.

Introduction: The analysis of radiopacity in radiographic exams is important for dentists not only for the differentiation between dental structures, but also for the assessment of infiltration in dental restorations and the diagnosis of dental caries. Besides the clinical significance, the differentiation of restorative materials based on their radiopacity is potentially useful in Forensic Odontology because it may support the human identification process. Objective: This study aimed to assess the radiopacity of the composites Tetric N Ceram, Z100, Z250 and Z350 through digital radiographs. Methods: An experimental in vitro study was performed with 16 test samples measuring 2x4mm. An aluminum scale with 9 levels (thickness of 1mm for each level) was used as a comparative source in face of the radiopacity levels detected for the composites in the digital radiograph system. The radiopacity of each composite and each level of the scale was analyzed 12 times, in 3 different moments. The radiopacity values obtained between the scale and the composites were statistically associated to indicate which scale level represents better the composite analyzed. Results: The composite Tetric corresponded to the scale level 1 (the most radiopaque). The composite Z100 presented values closer to the scale level 3. The composite Z250 ranged between levels 3 and 4, but did not presented statistical association. The composite Z350 presented statistical association with scale levels 3 and 4. Conclusion: Each composite presented distinct characteristics of radiopacity that could possibly contribute to the human identification process in Forensic Odontology. In specific, the composite Tetric had the highest radiopacity value. Despite less radiopaque, the composites Z100, Z250 and Z350 presented values within the standards expected (required by ISO 4049). Future studies are necessary with other composites in order to understand better the potential application for forensic purposes.

Diagnosis of alveolar and root fractures: an in vitro study comparing CBCT imaging with periapical radiographs

Abstract Objective To compare periapical radiograph (PR) and cone-beam computed tomography (CBCT) in the diagnosis of alveolar and root fractures. Material and Methods Sixty incisor teeth (20 higid and 40 with root fracture) from dogs were inserted in 60 anterior alveolar sockets (40 higid and 20 with alveolar fracture) of 15 macerated canine maxillae. Each fractured socket had a root fractured tooth inserted in it. Afterwards, each maxilla was submitted to PR in two different vertical angulation incidences, and to CBCT imaging with a small field of view (FOV) and high-definition protocol. Images were randomized and posteriorly analyzed by two oral and maxillofacial radiologists two times, with a two-week interval between observations. Results Sensitivity and specificity values were good for root fractures for PR and CBCT. For alveolar fractures, sensitivity ranged from 0.10 to 0.90 for PR and from 0.50 to 0.65 for CBCT. Specificity for alveolar fractures showed lower results than for root fractures for PR and CBCT. Areas under the ROC curve showed good results for both PR and CBCT for root fractures. However, results were fair for both PR and CBCT for alveolar fractures. When submitted to repeated measures ANOVA tests, there was a statistically significant difference between PR and CBCT for root fractures. Root fracture intraobserver agreement ranged from 0.90 to 0.93, and alveolar fracture intraobserver agreement ranged from 0.30 to 0.57. Interobserver agreement results were substantial for root fractures and poor/fair for alveolar fractures (0.11 for PR and 0.30 for CBCT). Conclusion Periapical radiograph with two different vertical angulations may be considered an accurate method to detect root fractures. However, PR showed poorer results than CBCT for the diagnosis of alveolar fractures. When no fractures are diagnosed in PR and the patient describes pain symptoms, the subsequent exam of choice is CBCT.

Assessment of three methods of geometric image reconstruction for digital subtraction radiography.

OBJECTIVES: To evaluate three methods of geometric image reconstruction for digital subtraction radiography (DSR). METHODS: Digital periapical radiographs were acquired of 24 teeth with the X-ray tube at 6 different geometric configurations of vertical (V) and horizontal (H) angles: V0°H0°, V0°H10°, V10°H0°, V10°H10°, V20°H0° and V20°H10°. All 144 images were registered in pairs (Group V0°H0° + 1 of the 6 groups) 3 times by using the Emago(®) (Oral Diagnostic Systems, Amsterdam, Netherlands) with manual selection and Regeemy with manual and automatic selections. After geometric reconstruction on the two software applications under different modes of selection, all images were subtracted and the standard deviation of grey values was obtained as a measure of image noise. All measurements were repeated after 15 days to evaluate the method error. Values of image noise were statistically analyzed by one-way ANOVA for differences between methods and between projection angles, followed by Tukey's test at a level of significance of 5%. RESULTS: Significant differences were found between most of the projection angles for the three reconstruction methods. Image subtraction after manual selection-based reconstruction on Regeemy presented the lowest values of image noise, except on group V0°H0°. The groups V10°H0° and V20°H0° were not significantly different between the manual selection-based reconstruction in Regeemy and automatic selection-based reconstruction in Regeemy methods. CONCLUSIONS: The Regeemy software on manual mode revealed better quality of geometric image reconstruction for DSR than the Regeemy on automatic mode and the Emago on manual mode, when the radiographic images were obtained at V and H angles used in the present investigation.

Reproducibility between conventional and digital periapical radiography for bone height measurement / Concordancia entre la radiografía periapical convencional y digital para medición de la altura ósea

Background. Several diagnostic aids are available for bone height measurement. Digital and conventional radiographs are the two ones most used in Dentistry. Few studies accounting for accuracy and precision have been conducted to compare these methods. Objective. The aim of this study was to estimate reproducibility between conventional and digital periapical radiography in bone height measurement in patients with chronic periodontitis. Methods. a consistency diagnostic test study was performed. 136 patients with chronic periodontitis were included, selecting the worst prognosis teeth and two radiographs -conventional and digital- were taken for each one. Two experienced and blinded examiners performed radiographic measurements. Reproducibility was obtained through Lin's concordance correlation coefficient by using the statistical package STATA™ for Windows. Results. Average age was 38.8 (SD: 9.9) and 61.6 % were female patients. 125 pairs of matched radiographs for 1000 measurements were evaluated. Overall reproducibility between the methods for mesial and distal measurements were 0.62 (95% CI: 0.55-0.70) and 0.64 (95% CI: 0.57-0.71) respectively. Conclusions. Reproducibility between methods was considered poor, including subgroup analysis, therefore, reproducibility between methods is minimal. Usage of these methods in periodontics should be made implementing the whole knowledge of the technical features and the advantages of these systems.

Antecedentes. Diversas ayudas diagnósticas están disponibles para la medición de la altura ósea; las dos más empleadas en odontología son la radiografía periapical convencional y la digital. A la fecha se cuenta con pocos estudios que den cuenta de la precisión y exactitud al compararlos. Objetivo. Estimar la concordancia entre la radiografía periapical convencional y la digital para la medición de la altura ósea en pacientes con periodontitis crónica. Métodos. Se realizó un estudio de pruebas diagnósticas de consistencia en 136 pacientes con periodontitis crónica seleccionando el diente con peor pronóstico. Se obtuvieron dos radiografías -convencional y digital- para cada diente y dos examinadores cegados realizaron las mediciones radiográficas. La concordancia se obtuvo con el coeficiente de correlación y concordancia de Lin empleando el paquete Stata para Windows. Resultados. La edad promedio fue 38.8 años (DE: 9.9) y 61.6% de los pacientes fueron mujeres. Se evaluaron 125 pares de radiografías para 1000 mediciones en total. La concordancia global fue 0.62 (IC 95%: 0.55-0.70) y 0.64 (IC 95%: 0.57-0.71) para las mediciones mesiales y distales respectivamente. Conclusiones. La concordancia entre los métodos se consideró pobre incluso en el análisis por subgrupos por tanto la reproducibilidad es mínima. El uso de estos métodos en periodoncia debe hacerse empleando el conocimiento completo de las características técnicas y ventajas de estos sistemas.

Evaluation of the reliability of measurements in cephalograms generated from cone beam computed tomography.

OBJECTIVE: The purpose was to compare angular and linear measurements generated in digital cephalometric radiographs and cephalograms synthesized from three-dimensional images. METHODS: Twenty-six individuals (12 men and 14 women) with mean age of 26.3 years were selected. Digital cephalometric radiographs and CBCTs were taken on the same day. The images were imported and analyzed on Dolphin Imaging V.10.5 software, which synthesized cephalograms in perspective projection and magnification of 9.7%. A single observer marked the points and repeated the procedure with an interval of time of ten days to evaluate intraexaminer error. In the statistical analysis paired Student's t test was used to establish the correlation between the measurements. RESULTS: The angular measurements GoGn.SN and IMPA, which involved the Gonial point (Go) and the linear measurements that involved the lips presented significant difference (p < 0.05). The other measurements presented good correlation. CONCLUSIONS: The measurements in the synthesized cephalograms proved to be reliable.

The evolution of cephalometric diagnosis in orthodontics.

INTRODUCTION: Although the development of CT have represented a landmark in diagnostic imaging, its use in Dentistry turned out very discretely over the years. With the appearance of programs for analysis of three-dimensional images, specific for Orthodontics and Orthognathic surgery, a new reality is being built. OBJECTIVE: The authors of this study aim to inform the orthodontic society of fundamentals about digital cephalometric radiographic image and computed tomography, discussing about: Field of view (FOV), radiation doses, demands for the use in Orthodontics and radiographic simulations.

Radiopacity assessment of composite resins through digital systems and InSight intraoral film / Avaliação da radiopacidade de resinas compostas por meio de sistemas digitais e filme radiográfico InSight

Objective: this study aimed to assess the radiopacity of eight composite resins recommended for class II restorations. Materials and method: hence, 2 mm thick and 4 mm in diameter test specimens were made and compared to enamel, dentin, and aluminum using four digital systems: two semi-direct by storage phosphor image plates (SPIP) - Digora™, and DenOptix™, two charged couple devices (CCD) - Sens-A-Ray™ and Computerized Dental Radiograph (CDR™), and radiographic film Kodak Insight IS-21™. The radiographs were scanned to obtain the indirect digital image, and along with direct and semi-direct digital images the radiographic densities were assessed in specific software. The pixel values from the aluminum step wedge were submitted to a linear regression from where the equivalent in millimeters for enamel, dentin, and resins were determined. Results: density means of resins were equal or superior to the means obtained for enamel in all digital systems and the conventional film. SureFil™ resin presented greater numerical radiopacity in all digital systems and the radiographic film. ALERT™ resin showed the smallest radiopacity among the studied resins in all digital systems and radiographic film. ALERT™ and Definite™ were statistically equivalent to enamel in the Sens-A-Ray™ system and in radiographic film. The remaining resins (Charisma™, FillMagic™, P60™, Prodigy™, SureFil™, and Z250™) presented higher radiopacities in comparison to enamel. Only ALERT™ presented radiopacity similar to enamel in other digital systems (CDR™, DenOptix™, and Digora™). In these digital systems, Charisma™, Definite™, FillMagic™, P60™, Prodigy™, SureFil™, and Z250™ were more radiopaque than enamel. Conclusion: all resins showed equal or higher radiopacities of enamel in all assessment systems. There was a statistical correlation between systems CDR™ and Sens-A-Ray™, and between Digora™ and DenOptix™; Sens-A-Ray™ also showed correlation with radiographic film. The percentage of density means equivalent to aluminum millimeters for enamel and dentin were 119.6% and 101.6%, respectively.

Objetivo: este estudo teve como objetivo avaliar a radiopacidade de oito tipos de resinas compostas indicadas para restaurações de classe II. Materiais e método: para tanto foram confeccionados corpos de prova de 2 mm de espessura e 4 mm de largura, os quais foram comparados com esmalte, dentina e alumínio, utilizando- se quatro sistemas digitais, sendo dois semidiretos por placas de fósforo fotoestimuladas - Digora® e DenOptix ®, dois CCD - Sens-A-Ray® e CDR®, e também o filme radiográfico Kodak Insight IS-21®. As radiografias foram escaneadas, obtendo-se imagem digital indireta, e, juntamente com as imagens digitais diretas e semidiretas, suas densidades radiográficas foram avaliadas em software específico. Os valores de pixel da escala de alumínio foram submetidos a uma regressão linear, de onde se pôde obter o equivalente em milímetros para o esmalte, dentina e resinas. Resultados: para todos os sistemas digitais e para o filme convencional, as médias das densidades das resinas foram iguais ou superiores às médias obtidas pelo esmalte. Para todos os sistemas digitais e para o filme radiográfico, a resina Surefil® apresentou maior radiopacidade numérica. A resina ALERT® apresentou a menor radiopacidade entre as resinas estudadas em todos os sistemas digitais e filme radiográfico. ALERT® e Difinite® foram estatisticamente equivalentes ao esmalte no sistema digital Sens-A-Ray® e no filme radiográfico. As demais resinas (Charisma®, FillMagic®, P60®, Prodigy®, Surefil® e Z250®) tiveram maior radiopacidade em comparação ao esmalte. Somente ALERT® teve radiopacidade similar à do esmalte em outros sistemas digitais (CDR®, Denoptix® e Digora ®). Nesses sistemas digitais, Charisma®, FillMagic®, P60®, Prodigy®, Surefil® e Z250® foram mais radiopacos do que o esmalte. Conclusão: todas as resinas, em todos os sistemas de avaliação, mostraram radiopacidade igual ou superior ao esmalte. Houve correlação estatística entre os sistemas CDR® e Sens-A-Ray® e entre Digora ® e DenOptix®, tendo o Sens-A-Ray® apresentado correlação também com o filme radiográfico. As médias de densidade equivalente em mm de alumínio em porcentagem para esmalte e dentina foram de 119,6% e 101,6%, respectivamente.

Evaluation of the reliability of measurements in cephalograms generated from cone beam computed tomography

OBJECTIVE: The purpose was to compare angular and linear measurements generated in digital cephalometric radiographs and cephalograms synthesized from three-dimensional images. METHODS: Twenty-six individuals (12 men and 14 women) with mean age of 26.3 years were selected. Digital cephalometric radiographs and CBCTs were taken on the same day. The images were imported and analyzed on Dolphin Imaging V.10.5 software, which synthesized cephalograms in perspective projection and magnification of 9.7%. A single observer marked the points and repeated the procedure with an interval of time of ten days to evaluate intraexaminer error. In the statistical analysis paired Student's t test was used to establish the correlation between the measurements. RESULTS: The angular measurements GoGn.SN and IMPA, which involved the Gonial point (Go) and the linear measurements that involved the lips presented significant difference (p < 0.05). The other measurements presented good correlation. CONCLUSION: The measurements in the synthesized cephalograms proved to be reliable.

OBJETIVO: comparar medidas angulares e lineares geradas em radiografias cefalométricas digitais e cefalogramas sintetizados a partir de imagens tridimensionais. MÉTODOS: selecionou-se 26 indivíduos (12 do sexo masculino e 14 do feminino), com média de idade de 26,3 anos, que realizaram no mesmo dia as radiografias cefalométricas digitais e tomografia computadorizada de feixe cônico. As imagens foram importadas e analisadas no software Dolphin Imaging V.10.5, que sintetizou cefalogramas com projeção perspectiva e magnificação de 9,7%. As marcações dos pontos foram realizadas por um único observador e repetidas com um intervalo de tempo de 10 dias para avaliação do erro intraexaminador. Para a análise estatística, utilizou-se o teste t de Student pareado para estabelecer a correlação entre as medidas. RESULTADOS: as medidas angulares GoGn.SN e IMPA, que envolviam o ponto Gônio (Go), e as medidas lineares que envolviam os lábios, apresentaram diferença significativa (p < 0,05). As outras medidas apresentaram boa correlação. CONCLUSÃO: as medições nos cefalogramas sintetizados mostraram-se confiáveis.

The evolution of cephalometric diagnosis in Orthodontics

INTRODUCTION: Although the development of CT have represented a landmark in diagnostic imaging, its use in Dentistry turned out very discretely over the years. With the appearance of programs for analysis of three-dimensional images, specific for Orthodontics and Orthognathic surgery, a new reality is being built. OBJECTIVE: The authors of this study aim to inform the orthodontic society of fundamentals about digital cephalometric radiographic image and computed tomography, discussing about: Field of view (FOV), radiation doses, demands for the use in Orthodontics and radiographic simulations.

INTRODUÇÃO: apesar do desenvolvimento da tomografia computadorizada ter representado um marco na área do diagnóstico por imagem, sua utilização em Odontologia deu-se de forma muito discreta ao longo dos anos. Com o surgimento de programas para análises de imagens tridimensionais, específicos para Ortodontia e Cirurgia Ortognática, uma nova realidade está sendo construída. OBJETIVO: os autores do presente artigo têm o objetivo de informar à sociedade ortodôntica fundamentos sobre imagem radiográfica cefalométrica digital e tomografia computadorizada, discutindo sobre o campo de visão (FOV), doses de radiação, exigências para o uso em Ortodontia e simulações radiográficas.

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.

Gray scale inversion in digital image for measurement of tooth length

The aim of this study was to assess the applicability of gray scale inversion in performing digital linear endodontic measurements. Standardized digital images were taken of 40 extracted human permanent single-rooted teeth with K-files size 15 placed at different lengths in the root canal, using the CDR Wireless® digital system. All images were treated with Positive, a digital tool that inverts the grayscale value. Eight radiologists measured the distance between the lower limit of the rubber stop and the tip of the file on both original and positive images. After 15 days, they repeated this procedure in 50% of the image samples. The intra- and inter-examiner agreement was analyzed by intraclass correlation test, and the comparison between the two image groups and the actual lengths by the Student's t-test (α=0.05). Intra- and inter-examiner evaluation showed high reproducibility (r>0.95) of both original and positive images. No statistically significant differences (p>0.05) were found between measurements performed on original and positive images, but both differed significantly from the actual lengths (p<0.05). Gray scale inversion has low applicability in measuring endodontic files, since it did not improve the accuracy of measurements.

O objetivo deste estudo foi avaliar a aplicabilidade da inversão da escala de cinza na realização de mensurações endodônticas lineares digitais. Quarenta dentes unirradiculares humanos extraídos foram radiografados com limas K tamanho 15 posicionadas no canal radicular em diferentes comprimentos, usando o sistema digital CDR Wireless®. Todas as imagens foram tratadas com Positive, uma ferramenta digital que inverte os valores da escala de cinza. Oito radiologistas mediram a distância entre o limite inferior do stop de borracha e a ponta da lima endodôntica nas imagens originais e positivas. Após quinze dias, eles repetiram esse procedimento em 50% da amostra. A concordância intra- e interobservador foi analisada pelo teste de correlação intraclasse e a comparação entre os dois grupos de imagem e os valores reais, pelo teste t-Student (α=0,05). A análise intra- e interobservador apresentou elevada reprodutibilidade (r>0,95) das imagens original e Positive. Não foi encontrada diferença (p>0,05) entre as medidas realizadas nas imagens original e positiva, mas ambas diferiram dos valores reais (p<0,05). A inversão da escala de cinza tem baixa aplicabilidade na realização de mensuração endodôntica, considerando que as medidas não se apresentaram mais acuradas.

In vitro study on radiographic gray levels of biomaterials using two digital image methods / Estudo in vitro dos níveis radiográficos de cinza de biomateriais utilizando duas modalidades de imagem digital

PURPOSE: To compare the direct and indirect radiographic methods for assessing the gray levels of biomaterials employing the Digora for Windows and the Adobe Photoshop CS2 systems. METHODS: Specimens of biomaterials were made following manusfacturer's instructions and placed on phosphor storage plates (PSP) and on radiographic film for subsequent gray level assessment using the direct and indirect radiographic method, respectively. The radiographic density of each biomaterial was analyzed using Adobe Photoshop CS2 and Digora for Windows software. RESULTS: The distribution of gray levels found using the direct and indirect methods suggests that higher exposure times are correlated to lower reproducibility rates between groups. CONCLUSION: The indirect method is a feasible alternative to the direct method in assessing the radiographic gray levels of biomaterials, insofar as significant reproducibility was observed between groups for the exposure times of 0.2 to 0.5 seconds.

OBJETIVO: Comparar os métodos radiográficos direto e indireto para avaliar os níveis de cinza de biomateriais empregando os sistemas Digora for Windows e Adobe Photoshop CS2. MÉTODOS: corpos de prova confeccionados com biomateriais foram posicionados numa película radiográfica e numa placa de fósforo com protetor para a realização de exposições radiográficas e posterior avaliação dos níveis de cinza por meio dos métodos indireto e direto, respectivamente. A densidade radiográfica de cada biomaterial foi analisada usando-se os sistemas Adobe Photoshop CS2 e Digora for Windows. RESULTADOS: A distribuição de níveis de cinza observada por meio dos métodos direto e indireto sugeriu uma menor reprodutibilidade entre grupos quanto maior o tempo de exposição. CONCLUSÃO: O método indireto constitui uma alternativa viável ao método direto para avaliar os níveis radiográficos de cinza de biomateriais na medida em que foi observada uma reprodutibilidade significativa entre grupos nos tempos de exposição de 0,2 a 0,5 segundos.

Influência dos simuladores de tecidos moles na densidade óssea e dentária por meio de duas análises radiográficas: subtração digital e intensidade de pixel / Influence of soft tissue materials in bone and tooth density through two radiographic analyses: digital subtraction and pixel intensity

Esse estudo teve como objetivo avaliar a influência dos simuladores de tecidos moles na imagem radiográfica digital, da região óssea e dental, pela subtração radiográfica e análise da intensidade de pixel. 30 mandíbulas humanas com 2 dentes posteriores foram selecionadas. Um dispositivo para o posicionamento do cilindro de raios X, mandíbula e sensor CCD eHD Visualix Gendex foi confeccionado. As mandíbulas foram posicionadas no dispositivo e 5 materiais simuladores de tecido mole (Acrílico, Cera, Água, Madeira e Tecido bovino) nas espessuras de 10mm, 15mm e 20mm foram posicionados anteriormente a mandíbula, em seqüência para a realização das tomadas radiográficas com 65 kV, 7mA, distância foco-sensor de 30 cm, e 0,08s. As imagens foram exportadas em 8 e 16 bits para análise. A subtração foi realizada com o programa X-Poseit usando a imagem sem material como referência da imagem com o material, em duas regiões, osso e estrutura dental. A área de ganho de densidade óssea e dental foi avaliada quanto à influência dos materiais e espessuras. A análise por intensidade de pixel foi realizada tanto no osso quanto na estrutura dental, numa área de 100x100pixels, com o programa ImageJ. Foi adotado o nível de significância de 0,05. Os resultados da subtração radiográfica digital e intensidade de pixel mostraram que tanto os simuladores testados influenciaram o ganho de densidade na região do osso. Entretanto, não foi encontrada diferenças entre os materiais e espessuras testados. Na região dental, tanto a analise por subtração quanto a por intensidade de pixel mostraram que os simuladores de tecido mole não influenciaram a densidade dessas regiões. A avaliação da profundidade de bit mostrou que não houve diferença entre os resultados. Podemos concluir que os simuladores de tecido mole influenciaram na densidade óssea e dental.

This study aimed to evaluate the effect of soft tissue simulators in digital radiographic image, of tooth and bone, by digital subtraction radiography and pixel intensity analysis. 30 human mandibles with two posterior teeth were selected. A device for positioning the cylinder X-ray, jaw and EHD Visualix Gendex CCD sensor was manufactured. The jaws were positioned on the device and 5 soft tissue simulators materials (acrylic, wax, water, wood, and bovine tissue) in thicknesses of 10mm, 15mm and 20mm, were positioned in front of the jaw line, in sequence to perform the X-ray expositions at 65 kV, 7mA, plate-focus distance of 30 cm and the exposure time of 0.08 s. The images were exported in 8 and 16 bit for analysis. The subtraction was performed with the X-Poseit image without using the image as a reference material with the material in two regions, bone and tooth structure. The gain area in bone and tooth density was assessed and the difference between material and thickness were evaluated. The pixel intensity analysis was performed both in bone and tooth structure in an area of 100x100pixels with ImageJ. Significance level of 0,05 was adopted. The results of digital subtraction radiography showed that both the material and the thickness tested didn’t influence the gain of density in bone. Pixel intensity analisys in bone region didn’t show these differences, except for lower density observed in the 14 image without material comparing with the materials tested. In the dental region, both subtraction and pixel intensity showed that soft tissue simulators influence the density of these regions. However there was no difference between the materials and thicknesses tested. The evaluation of the bit depth, showed no difference between the results. We can conclude that soft tissue materials influence bone and dental density.