I read, with interest, the article entitled "Clinical and Para-clinical Presentations of Endobronchial Tuberculosis" by Ahmadi Hoseini H. S. et al. (1) published in this journal. I would like to focus on some details about the chest X-ray of patients as elaborated by the authors in the results section.

Purpose: Root fracture is a clinical problem which often is difficult to detect and diagnose. As the root fracture detection is based on demonstration of a fracture line or lines, radiographic examination is important. The aim of this study was to compare diagnostic efficacy of direct digital RADIOGRAPHY with conventional RADIOGRAPHY for detecting experimental root fractures.Materials & Methods: This study was based on observational diagnostic method which eighty one extracted single rooted human teeth were endodontically instrumented and divided into two groups, a control group of 40 teeth and a fractured group of 41 teeth in which root fractures were produced with Instron machine. Each tooth was imaged using the parallel technique with a CCD-based digital system and E-speed film. The images were interpreted by three experienced oral and maxillofacial radiologists without prior knowledge of the distribution of the root fractures. Three image groups were taken: conventional film, digital images and enhanced digital images. Sensitivity, specificity, false negative and false positive percentage, accuracy of each method in comparison with golden standard (visual examination of fractured and intact teeth) were analyzed. The degree of agreement in detecting root fractures with each imaging system compared with each other was expressed as the kappa value. Results: The sensitivity, specificity and accuracy for root fractures in conventional RADIOGRAPHY were 73.2%, 87.5% and 80.2% respectively, in direct digital RADIOGRAPHY were 78%, 77.5% and 77.8% respectively and in enhanced direct digital RADIOGRAPHY were 82.9%, 85% and 84% respectively. The most sensitive was enhanced direct digital RADIOGRAPHY and the most specific was conventional RADIOGRAPHY.There was fair to good agreement between conventional RADIOGRAPHY and digital RADIOGRAPHY (k=0.68), fair to good agreement between enhanced digital RADIOGRAPHY and conventional RADIOGRAPHY (k=0.73) and excellent agreement between digital RADIOGRAPHY and enhanced digital RADIOGRAPHY (k=0.90).Conclusions: The diagnostic efficacy of Conventional RADIOGRAPHY, digital RADIOGRAPHY and enhanced digital RADIOGRAPHY in detecting root fractures was comparable with each other.

Introduction: In addition to conventional RADIOGRAPHY, several other techniques such as stereoRADIOGRAPHY have so far been proposed to determine the position of impacted maxillary canines. The purpose of this study was to evaluate the diagnostic value of panoramic RADIOGRAPHY and stereoRADIOGRAPHY for determining the position of impacted maxillary canines.Materials and Methods: This was a prognostic, cross sectional study. A total of 30 impacted maxillary canines in 23 patients candidated for surgery were included. Four well coordinated observers separately determined the position of impacted maxillary canines using both panoramic RADIOGRAPHY and stereoRADIOGRAPHY. In the next phase, the exact position of impacted canines were determined through surgical exploration. Mc-Nemar and kappa index were applied for statistical data analysis. (a=0.05).Results: The rate of correct diagnosis in stereoRADIOGRAPHY and conventional RADIOGRAPHY was 93.35% and 60.82% respectively which demonstrated a statistically significant difference. With each method, there were no significant differences among observers. Sensitivity and specificity with stereoRADIOGRAPHY were calculated 91.98% and 94.78% respectively. With conventional RADIOGRAPHY however these values dropped to 49.90% and 74.11% respectively.Conclusion: StereoRADIOGRAPHY seems quite reliable for determining the position of impacted maxillary canines. On the contrary, conventional RADIOGRAPHY per se does not look precise enogh to determin the position of impacted maxillary canines.