In Vitro Comparative Study of the Working Length Determination with Radiovisiography and Conventional Radiography in Dilacerated Canals

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Original Research In Vitro Comparative Study of the Working Length Determination with Radiovisiography and Conventional Radiography in Dilacerated Canals Ali Bagherpour1, Maryam Mojtahedi2, Mahrokh Imanimoghaddam3, Hamid Jafarzadeh4 1 Dental Materials Research Center and Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran 2 Department of Restorative Dentistry, Faculty of Dentistry, Birjand University of Medical Sciences, Birjand, Iran 3 Oral and Maxillofacial Diseases Research Center and Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran 4 Dental Research Center, Department of Endodontics, Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran Received 1 November 2014 and Accepted 3 March 2015 Abstract Introduction: The aim of this study was to compare digital and conventional radiography in determining the working length of dilacerated canals. Methods: Thirty nine human extracted single-rooted teeth with root curvature more than 35 degrees were included in this study. After access preparation, a file was inserted into the canal and advanced until the file tip was visualized at the foramen. With measurement of the file length using a millimeter ruler, true canal length was determined for each canal. Then, teeth were mounted in acrylic blocks and canal length was estimated by using on-screen digital radiography with both 3- and 6-clicks measurement and from conventional radiography by conforming a preserved file on the image of the root canal. Results: There were no significant differences in measurement accuracy between the true canal length and conventional radiographic length, but there were significant difference between both digital radiographic techniques with true canal length. There was no significant correlation between root curvature and canal length estimation error of studied methods. Conclusion: In dilacerated canals, the accuracy of determination of working length by using conventional radiography is higher than digital radiography. Key words: Digital radiography; conventional radiography; working length; root curvature; dilaceration. --------------------------------------------------------- Bagherpour A, Mojtahedi M, Imanimoghaddam M, Jafarzadeh H. In Vitro Comparative Study of the Working Length Determination with Radiovisiography and Conventional Radiography in Dilacerated Canals. J Dent Mater Tech 2015; 4(2): 65-71. Introduction An important part of successful endodontic treatment is a true working length determination for root canal cleaning, shaping, and obturation. The working length refers to the distance from the coronal reference point to the point at which canal preparation should be terminated (1). To estimate the canal length before instrumentation in endodontic treatment, conventional radiography and digital radiography may be used. Radiographic technique described by Ingle is the most common method used for determination of the working length; however, its accuracy is under question. A major limitation in this technique is that the apical constriction cannot be recognized correctly. The clinicians' bias in radiographic interpretation is another concern (2). Bagherpour et al. JDMT, Volume 4, Number 2, June 2015 65 Measurement of the working length may be much more difficult in dilacerated canals because of different tactile sense in these canals and curvature of the canal in radiograph which make the measuring difficult (3, 4). Nowadays, digital radiography is used in different fields of dentistry. It may have some potential benefits in endodontics, too. It has some advantages over the conventional radiography including less exposure time, image acquisition, manipulation, storage, retrieval, and transmission to remote site in a digital format, elimination of wet processing and considerable reduction in the time lapse between image acquisition and display (5). This technique may be helpful in working length determination in dilacerated canals because of its ability to choose some points in the canal and electronic measurement of the line between these points. The purpose of this study was to compare digital and conventional radiography in determining the working length of dilacerated canals. Materials and Methods Thirty nine human single-rooted extracted teeth with severe root curvature, closed apex, and no root crack/fracture were obtained and periapical radiograph was taken. The images were used to select teeth based on inclusive criteria consisting of the presence of a radiographic visible root canal, the absence of external or internal resorption, presence of only 1 orifice and one foramen, and the root curvature≥35 degrees, as established by the Schneider method (6). Standard endodontic access cavity preparation was made in all teeth and canal patency verified with a #8 K-file (Dentsply, Maillefer, Ballaigues, Switzerland). Then the incisal/occlusal surface of all teeth were flattened perpendicular to the long axis of the roots to obtain a reliable incisal/occlusal reference point. The actual working length for each tooth was obtained by inserting #8 K-file (Dentsply, Maillefer, Ballaigues, Switzerland) into the canals until it passed the apical foramen, and then pulling back onto a smooth metallic surface. A rubber stop was used to mark the file at its coronal reference point. The file was removed and canal length was determined using an endodontic ruler. To simulate alveolar bone tissue and clinical conditions, the teeth were mounted in plastic tubes, using an opaque acrylic material. Specimens then were imaged with both conventional and digital radiography using long cone and parallel technique. E-speed films (AGFA, Osaka, Japan) was chosen for the conventional radiography which were exposed with X-ray generated by a Planmecca unit (Planmecca, Helsinki, Finland) operating at 70 KVP and 8 mA. Optimal exposure time was selected to be 0.12 s. To obtain digital radiographs, the techniques were similar to that of conventional radiography, the only difference was using CCD sensor (Schick Technologies, New York, USA) instead of conventional film. The specimens were placed over the packet film or sensor using a polyvinyl siloxane jig to allow changing of the image recording medium without moving the specimen or losing the relationship between the tooth and the image recording surface and an XCP device was used to ensure consistency of angulation and source-toobject distance for the radiographs and the radiovisiographic (RVG) images. In all cases, a distance of 36 cm was established between the X-ray source and the film/sensor and the object was in the closest contact with the image recording surface. For each tooth, the direction of exposure was based on the direction of root curvature, which means teeth with mesiodistal curvature were radiographed in a buccal to lingual orientation and teeth with buccolingual curvature were radiographed in a mesial to distal orientation. In the case of digital system, the canal length was estimated by digital ruler feature of the RVG system with both 3-clicks measurement (the first click at the flat coronal reference point, the second click at the tip of the angle along the coronal curvature, and the final click at the radiographic apex) and 6-clicks measurement (three clicks as mentioned above and three intermediate clicks). Each RVG image was calibrated using the orthodontic arch wire of known diameter. Measurements of the conventional radiographic images were made directly on the film with the aid of a precurved file. A #15 K-file (Dentsply, Maillefer, Ballaigues, Switzerland) was adapted to the radiograph to simulate its canal curvature from the flat occlusal reference point to radiographic apex and this length was marked. After straightening the file, the measurement was done with the aid of an endodontic ruler. All images were assessed under ideal conditions and measurements were made by two trained examiners. Statistical Package for the Social Sciences (SPSS) 16.0 for Windows (SPSS Inc., Chicago, IL, USA), and Microsoft Office Excel 2007 were used to carry out statistical analysis. Pearson Correlation Coefficients and GLM repeated measures were used for statistical analysis. The critical level of significance was set at P<0.05. Results The minimum, maximum, and mean ± S.D. of the root curvature were 35, 83 and 46.15±12.19 degrees. The normality of the data distribution for root curvature and working length measurements in different methods was analyzed with the Kolmogorov-Smirnov test (P>0.05). Table 1 shows that there is a strong Pearson's correlation coefficient between two observers in 3 66 JDMT, Volume 4, Number 2, June 2015 Working Length Determination methods; since the mean values for each type of measurement was used. Also, it was concluded that the agreement between two observers in conventional method is the lowest. GLM repeated measures showed that there was a significant value for Mauchly's Test of Sphericity that indicates the assumption of sphericity has been violated (Approx. Chi-Square=102.08, P<0.001). In this condition, a correctional adjustment called Greenhouse-Geisser was used. ANOVA with repeated measures with a Greenhouse-Geisser correction revealed that the mean measurements for root canal length were statistically significantly different (F (1.63, 62.24) =27.84, P<0.001). Table 2 presented the results of the Bonferroni post-hoc test, which allows us to discover which specific means differed. There were no significant differences in measurement accuracy between the true working length and conventional radiographic length (mean conventional) (P=0.356), but there were significant difference between the both digital radiographic techniques with working length and mean conventional length (P<0.05) (Table 2, Fig. 1). The maximum percentage of magnification was related to 3-click digital radiography and the minimum was related to working length estimation with conventional radiography (Table 3, Fig. 1). Both digital radiographic techniques underestimated the working length but conventional radiographic techniques overestimated that. There was no significant correlation between root curvature and canal length estimation error of these three methods (P>0.05) (Table 4). Table 1. Pearson correlation coefficients and p-values for comparing two practitioners in determining the working length by digital radiography and conventional radiography RVG3_2 RVG6_2 Conventional_2 RVG3_1 Pearson Correlation .998** .998** .957** Sig. (2-tailed) .000 .000 .000 RVG6_1 N Pearson Correlation 39 .997** 39 .998** 39 .953** Sig. (2-tailed) .000 .000 .000 N Conventianal_1 Pearson Correlation 39 .973** 39 .973** 39 .954** Sig. (2-tailed) .000 .000 .000 N 39 39 39 **. Correlation is significant at the 0.01 level (2-tailed). Bagherpour et al. JDMT, Volume 4, Number 2, June 2015 67 (I) Measurement WLa Mean RVG3 Mean RVG6 Table 2. The results of the Bonferroni post-hoc test (J) Measurement Mean Difference P 95% Confidence Interval for Difference (I-J) Lower Bound Upper Bound Mean RVG3b .488* .000 .229 .747 Mean RVG6c .390* .001 .126 .654 Mean Conventionald -.135 .356 -.327 .058 WL -.488* .000 -.747 -.229 Mean RVG6 -.098* .000 -.142 -.053 Mean Conventional -.622* .000 -.873 -.372 WL -.390* .001 -.654 -.126 Mean RVG3 .098* .000 .053 .142 Mean Conventional -.525* .000 -.774 -.276 Mean Conventional WL .135 .356 -.058 .327 Mean RVG3 .622* .000 .372 .873 Mean RVG6 .525* .000 .276 .774 aWL: Working Length, bMean RVG3: The average of two observers findings in 3-clicks method, cMean RVG6: The average of two observers findings in 6-clicks method, dMean Conventional: The average of two observers findings in conventional method Table 3. Mean error percentage of working length in 3 studied methods. Conventional RVG (3-clicks) RVG (6-clicks) Mean Error (%) 0.78 - 2.45 - 1.93 Table 4. Pearson correlation coefficients between root curvature (angle) and canal length estimation error in 3 different methods Angle RVG3 Error RVG6 Error Conventional Percent Percent Error Percent Angle Pearson Correlation 1 -.099 -.059 .001 Sig. (2-tailed) .547 .721 .995 N 39 39 39 39 68 JDMT, Volume 4, Number 2, June 2015 Working Length Determination Figure 1. The difference between three studied methods in determining the working length WL: Working Length RVG3: Mean 3-clicks method measurement RVG6: Mean 6-clicks method measurement Discussion Determination of working length is considered as an important stage in endodontic treatment. Various methods are used to do this, including patient reflex, paper point, conventional radiography, and digital radiography (7, 8). Considering the fact that the use of digital radiography can lead to a lower radiation dose for the patient and lower number of radiographs, this study has been designed to compare the efficiency of the conventional and the digital radiography systems in regard to actual working length in dilacerated canals. Magnification has been defined as enlargement of the image of an object in radiographic films and it can be minimized by placing the object and the film as close to each other as possible and to increase the distance between the X-ray source and the film. On the other hand, paralleling technique can be used to place the object at the center of the X-ray beams, thus minimizing distortion (5). In this study, the object and the film were placed as close to each other as possible and paralleling technique was used in imaging. To increase measurement accuracy in our study two independent observers were used. Inter-observer correlation coefficients, at the level of 0.01, showed a significant correlation. Some researchers reached Bagherpour et al. similar results (9-13). In all these studies significant inter-observer correlation at the level of 0.01 was found. Lack of meaningful difference between working length and the conventional method has also been found by other researchers (2, 13-18). However, Shearer et al. (19) and Burger et al. (10) found a meaningful difference between the conventional method and working length. The difference found in the study carried out by Shearer et al. (19) may be due to greater volume of the sample size (60 teeth) and not using enhancement while employing digital radiography, while in the study conducted by Burger et al. (10) it may be caused by a more accurate measurement of working length through the use of ×2 magnification and difference in the curvature of the roots used (7 to 47 degrees) in comparison to our study. Moreover, in a study carried out by Mehdizadeh et al. (14) the reason for the difference in measurements gained through the conventional method and working length could be attributed to the higher volume of the sample pool (65 extracted teeth), not using severely curved teeth, the use of dry human mandibles instead of mounting them in acrylic resins and superimposition of a grid on the film for a more precise working length measurement. JDMT, Volume 4, Number 2, June 2015 69 The existence of meaningful difference between measurements gained by the application of RVG method with working length was in line with results produced by many past studies (10, 14, 15, 20, 21). However, Almenar Garcia et al. (17) and Mohtavipour et al. (13) did not find a meaningful difference between the two. In the study conducted by Almenar Garcia et al. (17) this may be due to the use of vernier caliper in the measurements yielded by conventional radiography. Mohtavipour et al. (13) declared that there is no difference between working length and measurements produced by RVG, and this may be due to the use of 60 extracted mandibular first molar with root curvature ranging from 0 to over 30 degrees and employment of 2- and 3-clicks. Our findings showed a meaningful difference in length measurement between the conventional and digital methods and this is in line with views expressed by Lamus et al. (16) and Shearer et al. (19). Other studies have concluded that a meaningful difference does not exist between conventional and digital methods (9-15, 20, 22-26). Among the factors accounting for the finding that no meaningful difference between the two methods exists, we can point to differences in the size of the sample pool, the kind of teeth used, the way they are mounted and measurement methods different from the one we employed in our study. An examination of the results of the present study indicates that the conventional method of measuring root canal length tended to error by overestimation. This confirms the findings of Shearer et al. (19) Ezoddini Ardakani et al. (24) and Brito-Junior et al. (12). However, it does not apply to canals with moderate curvature (20-36 degrees) in the study conducted by Mentes et al. (15). This may be due to the difference in root canal curvature of the teeth used compared to those we used in our study, or to the use of ×2 magnification in measurement of working length while using the conventional method. The study carried out by Mohtavipour et al. (13) demonstrated under-estimation in measuring canal length using the conventional method which may be attributed to differences in the kind of teeth used (mandibular first molar) and the degree of their curvature (from 0 to over 30 degrees) in comparison to our study. Huang et al. (27) reported that in using RVG with 2clicks, as the degree of curvature increases a equilibrium value of MeCpG steps (,+14 deg.) [31,44]. In comparison, methylation has a significantly lower stability cost when happening at major groove positions, such as 211 and 21 base pair from dyad (mutations 9 and 12), where the roll of the nucleosome bound conformation (+10 deg.) is more compatible with the equilibrium geometry of MeCpG steps. The nucleosome destabilizing effect of cytosine methylation increases with the number of methylated cytosines, following the same position dependence as the single methylations. The multiple-methylation case reveals that each major groove meth- PLOS Computational Biology | www.ploscompbiol.org 3 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning ylation destabilizes the nucleosome by around 1 kJ/mol (close to the average estimate of 2 kJ/mol obtained for from individual methylation studies), while each minor groove methylation destabilizes it by up to 5 kJ/mol (average free energy as single mutation is around 6 kJ/mol). This energetic position-dependence is the reverse of what was observed in a recent FRET/SAXS study [30]. The differences can be attributed to the use of different ionic conditions and different sequences: a modified Widom-601 sequence of 157 bp, which already contains multiple CpG steps in mixed orientations, and which could assume different positioning due to the introduction of new CpG steps and by effect of the methylation. The analysis of our trajectories reveals a larger root mean square deviation (RMSD) and fluctuation (RMSF; see Figures S2– S3 in Text S1) for the methylated nucleosomes, but failed to detect any systematic change in DNA geometry or in intermolecular DNA-histone energy related to methylation (Fig. S1B, S1C, S4–S6 in Text S1). The hydrophobic effect should favor orientation of the methyl group out from the solvent but this effect alone is not likely to justify the positional dependent stability changes in Figure 2, as the differential solvation of the methyl groups in the bound and unbound states is only in the order of a fraction of a water molecule (Figure S5 in Text S1). We find however, a reasonable correlation between methylation-induced changes in hydrogen bond and stacking interactions of the bases and the change in nucleosome stability (see Figure S6 in Text S1). This finding suggests that methylation-induced nucleosome destabilization is related to the poorer ability of methylated DNA to fit into the required conformation for DNA in a nucleosome. Changes in the elastic deformation energy between methylated and un-methylated DNA correlate with nucleosomal differential binding free energies To further analyze the idea that methylation-induced nucleosome destabilization is connected to a worse fit of methylated DNA into the required nucleosome-bound conformation, we computed the elastic energy of the nucleosomal DNA using a harmonic deformation method [36,37,44]. This method provides a rough estimate of the energy required to deform a DNA fiber to adopt the super helical conformation in the nucleosome (full details in Suppl. Information Text S1). As shown in Figure 2, there is an evident correlation between the increase that methylation produces in the elastic deformation energy (DDE def.) and the free energy variation (DDG bind.) computed from MD/TI calculations. Clearly, methylation increases the stiffness of the CpG step [31], raising the energy cost required to wrap DNA around the histone octamers. This extra energy cost will be smaller in regions of high positive roll (naked DNA MeCpG steps have a higher roll than CpG steps [31]) than in regions of high negative roll. Thus, simple elastic considerations explain why methylation is better tolerated when the DNA faces the histones through the major groove (where positive roll is required) that when it faces histones through the minor groove (where negative roll is required). Nucleosome methylation can give rise to nucleosome repositioning We have established that methylation affects the wrapping of DNA in nucleosomes, but how does this translate into chromatin structure? As noted above, accumulation of minor groove methylations strongly destabilizes the nucleosome, and could trigger nucleosome unfolding, or notable changes in positioning or phasing of DNA around the histone core. While accumulation of methylations might be well tolerated if placed in favorable positions, accumulation in unfavorable positions would destabilize the nucleosome, which might trigger changes in chromatin structure. Chromatin could in fact react in two different ways in response to significant levels of methylation in unfavorable positions: i) the DNA could either detach from the histone core, leading to nucleosome eviction or nucleosome repositioning, or ii) the DNA could rotate around the histone core, changing its phase to place MeCpG steps in favorable positions. Both effects are anticipated to alter DNA accessibility and impact gene expression regulation. The sub-microsecond time scale of our MD trajectories of methylated DNAs bound to nucleosomes is not large enough to capture these effects, but clear trends are visible in cases of multiple mutations occurring in unfavorable positions, where unmethylated and methylated DNA sequences are out of phase by around 28 degrees (Figure S7 in Text S1). Due to this repositioning, large or small, DNA could move and the nucleosome structure could assume a more compact and distorted conformation, as detected by Lee and Lee [29], or a slightly open conformation as found in Jimenez-Useche et al. [30]. Using the harmonic deformation method, we additionally predicted the change in stability induced by cytosine methylation for millions of different nucleosomal DNA sequences. Consistently with our calculations, we used two extreme scenarios to prepare our DNA sequences (see Fig. 3): i) all positions where the minor grooves contact the histone core are occupied by CpG steps, and ii) all positions where the major grooves contact the histone core are occupied by CpG steps. We then computed the elastic energy required to wrap the DNA around the histone proteins in unmethylated and methylated states, and, as expected, observed that methylation disfavors DNA wrapping (Figure 3A). We have rescaled the elastic energy differences with a factor of 0.23 to match the DDG prediction in figure 2B. In agreement with the rest of our results, our analysis confirms that the effect of methylation is position-dependent. In fact, the overall difference between the two extreme methylation scenarios (all-in-minor vs all-in-major) is larger than 60 kJ/mol, the average difference being around 15 kJ/ mol. We have also computed the elastic energy differences for a million sequences with CpG/MeCpG steps positioned at all possible intermediate locations with respect to the position (figure 3B). The large differences between the extreme cases can induce rotations of DNA around the histone core, shifting its phase to allow the placement of the methylated CpG steps facing the histones through the major groove. It is illustrative to compare the magnitude of CpG methylation penalty with sequence dependent differences. Since there are roughly 1.5e88 possible 147 base pairs long sequence combinations (i.e., (4n+4(n/2))/2, n = 147), it is unfeasible to calculate all the possible sequence effects. However, using our elastic model we can provide a range of values based on a reasonably large number of samples. If we consider all possible nucleosomal sequences in the yeast genome (around 12 Mbp), the energy difference between the best and the worst sequence that could form a nucleosome is 0.7 kj/mol per base (a minimum of 1 kJ/mol and maximum of around 1.7 kJ/mol per base, the first best and the last worst sequences are displayed in Table S3 in Text S1). We repeated the same calculation for one million random sequences and we obtained equivalent results. Placing one CpG step every helical turn gives an average energetic difference between minor groove and major groove methylation of 15 kJ/ mol, which translates into ,0.5 kJ/mol per methyl group, 2 kJ/ mol per base for the largest effects. Considering that not all nucleosome base pair steps are likely to be CpG steps, we can conclude that the balance between the destabilization due to CpG methylation and sequence repositioning will depend on the PLOS Computational Biology | www.ploscompbiol.org 4 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning Figure 3. Methylated and non-methylated DNA elastic deformation energies. (A) Distribution of deformation energies for 147 bplong random DNA sequences with CpG steps positioned every 10 base steps (one helical turn) in minor (red and dark red) and major (light and dark blue) grooves respectively. The energy values were rescaled by the slope of a best-fit straight line of figure 2, which is 0.23, to por la lectura a través de la lectura de la prensa. La educación en los medios las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio adquiere pleno derecho y entidad en la sección sexta titulada «competencias sociales y cívi- técnico de los aparatos. cas» que indica que «los alum- nos deberán ser capaces de juz- gar y tendrán espíritu crítico, lo que supone ser educados en los las programaciones oficiales, ya que, a lo largo de un medios y tener conciencia de su lugar y de su influencia estudio de los textos, los documentalistas del CLEMI en la sociedad». han podido señalar más de una centena de referencias a la educación de los medios en el seno de disciplinas 4. Un entorno positivo como el francés, la historia, la geografía, las lenguas, Si nos atenemos a las cifras, el panorama de la las artes plásticas : trabajos sobre las portadas de educación en medios es muy positivo. Una gran ope- prensa, reflexiones sobre temas mediáticos, análisis de ración de visibilidad como la «Semana de la prensa y publicidad, análisis de imágenes desde todos los ángu- de los medios en la escuela», coordinada por el CLE- los, reflexión sobre las noticias en los países europeos, MI, confirma año tras año, después de 17 convocato- información y opinión rias, el atractivo que ejerce sobre los profesores y los Esta presencia se constata desde la escuela mater- alumnos. Concebida como una gran operación de nal (2 a 6 años) donde, por ejemplo, se le pregunta a complementariedad entre la escuela y los profesiona- los niños más pequeños si saben diferenciar entre un les de los medios, alrededor del aprendizaje ciudada- periódico, un libro, un catálogo, a través de activida- no de la comunicación mediática, este evento moviliza des sensoriales, si saben para qué sirve un cartel, un durante toda una semana un porcentaje elevado de periódico, un cuaderno, un ordenador si son capa- centros escolares que representan un potencial de 4,3 ces de reconocer y distinguir imágenes de origen y de millones de alumnos (cifras de 2006). Basada en el naturaleza distintas. Podríamos continuar con más voluntariado, la semana permite desarrollar activida- ejemplos en todos los niveles de enseñanza y práctica- des más o menos ambiciosas centradas en la introduc- Páginas 43-48 ción de los medios en la vida de la escuela a través de la instalación de kioscos, organización de debates con profesionales y la confección por parte de los alumnos de documentos difundidos en los medios profesionales. Es la ocasión de dar un empujón a la educación en medios y de disfrutarlos. Los medios –un millar en 2006– se asocian de maneras diversas ofreciendo ejemplares de periódicos, acceso a noticias o a imágenes, proponiendo encuentros, permitiendo intervenir a los jóvenes en sus ondas o en sus columnas Esta operación da luz al trabajo de la educación en medios y moviliza a los diferentes participantes en el proyecto. 5. La formación de los docentes La formación es uno de los pilares principales de la educación en los medios. Su función es indispensable ya que no se trata de una disciplina, sino de una enseñanza que se hace sobre la base del voluntariado y del compromiso personal. Se trata de convencer, de mostrar, de interactuar. En primer lugar es necesario incluirla en la formación continua de los docentes, cuyo volumen se ha incrementado desde 1981 con la aparición de una verdadera política de formación continua de personal. Es difícil dar una imagen completa del volumen y del público, pero si nos atenemos a las cifras del CLEMI, hay más de 24.000 profesores que han asistido y se han involucrado durante 2004-05. 5.1. La formación continua En la mayoría de los casos, los profesores reciben su formación en contextos cercanos a su centro de trabajo, o incluso en este mismo. Después de una política centrada en la oferta que hacían los formadores, se valora más positivamente la demanda por parte del profesorado, ya que sólo así será verdaderamente fructífera. Los cursos de formación se repartieron en varias categorías: desde los formatos más tradicionales (cursos, debates, animaciones), hasta actividades de asesoramiento y de acompañamiento, y por supuesto los coloquios que permiten un trabajo en profundidad ya que van acompañados de expertos investigadores y profesionales. Citemos, por ejemplo en 2005, los coloquios del CLEMI-Toulouse sobre el cine documental o el del CLEMI-Dijon sobre «Políticos y medios: ¿connivencia?». Estos coloquios, que forman parte de un trabajo pedagógico regular, reagrupan a los diferentes participantes regionales y nacionales alrededor de grandes temas de la educación en medios y permiten generar nuevos conocimientos de aproximación y una profundización. Páginas 43-48 Hay otro tipo de formación original que se viene desarrollando desde hace menos tiempo, a través de cursos profesionales, como por ejemplo, en el Festival Internacional de Foto-periodismo «Visa para la imagen», en Perpignan. La formación se consolida en el curso, da acceso a las exposiciones, a las conferencias de profesionales y a los grandes debates, pero añade además propuestas pedagógicas y reflexiones didácticas destinadas a los docentes. Estas nuevas modalidades de formación son también consecuencia del agotamiento de la formación tradicional en las regiones. Los contenidos más frecuentes en formación continua conciernen tanto a los temas más clásicos como a los cambios que se están llevando a cabo en las prácticas mediáticas. Así encontramos distintas tendencias para 2004-05: La imagen desde el ángulo de la producción de imágenes animadas, el análisis de la imagen de la información o las imágenes del J.T. La prensa escrita y el periódico escolar. Internet y la información en línea. Medios y educación de los medios. 5.2 La formación inicial La formación inicial está aun en un grado muy ini- cial. El hecho de que la educación en medios no sea una disciplina impide su presencia en los IUFM (Institutos Universitarios de Formación de Maestros) que dan una prioridad absoluta a la didáctica de las disciplinas. En 2003, alrededor de 1.400 cursillistas sobre un total de 30.000 participaron en un momento u otro de un módulo de educación en medios. Estos módulos se ofrecen en función del interés que ese formador encuentra puntualmente y forman parte a menudo de varias disciplinas: documentación, letras, historia-geografía Estamos aún lejos de una política concertada en este dominio. La optativa «Cine-audiovisual» ha entrado desde hace muy poco tiempo en algunos IUFM destinada a obtener un certificado de enseñanza de la opción audiovisual y cine. Internet tiene cabida también en los cursos de formación inicial, recientemente con la aparición de un certificado informático y de Internet para los docentes, dirigido más a constatar competencias personales que a valorar una aptitud para enseñarlos. 6. ¿Y el futuro? El problema del futuro se plantea una vez más por la irrupción de nuevas técnicas y nuevos soportes. La difusión acelerada de lo digital replantea hoy muchas cuestiones relativas a prácticas mediáticas. Muchos Comunicar, 28, 2007 47 Comunicar, 28, 2007 Enrique Martínez-Salanova '2007 para Comunicar 48 trabajos que llevan el rótulo de la educación en medios solicitan una revisión ya que los conceptos cambian. La metodología elaborada en el marco de la educación en medios parece incluso permitir la inclinación de la sociedad de la información hacia una sociedad del conocimiento, como defiende la UNESCO. En Francia, se necesitaría unir las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio técnico de los aparatos. Los avances recientes en el reconocimiento de estos contenidos y las competencias que supondrían podrían permitirlo. Referencias CLEMI/ACADEMIE DE BORDEAUX (Ed.) (2003): Parcours médias au collège: approches disciplinaires et transdisciplinaires. Aquitaine, Sceren-CRDP. GONNET, J. (2001): Education aux médias. Les controverses fécondes. Paris, Hachette Education/CNDP. SAVINO, J.; MARMIESSE, C. et BENSA, F. (2005): L’éducation aux médias de la maternelle au lycée. Direction de l’Enseignement Scolaire. Paris, Ministère de l’Education Nationale, Sceren/CNDP, Témoigner. BEVORT, E. et FREMONT, P. (2001): Médias, violence et education. Paris, CNDP, Actes et rapports pour l’éducation. – www.clemi.org: fiches pédagogiques, rapports et liens avec les pages régionales/académiques. – www.ac-nancy-metz.fr/cinemav/quai.html: Le site «Quai des images» est dédié à l’enseignement du cinéma et de l’audiovisuel. – www.france5.fr/education: la rubrique «Côté profs» a une entrée «education aux médias». – www.educaunet.org: Programme européen d’éducation aux risques liés à Internet. dResedfeleexliobnuetsacón Páginas 43-48
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