|Year : 2009 | Volume
| Issue : 2 | Page : 67-71
Conventional and digital radiographic methods in the detection of simulated external root resorptions: A comparative study
CJ Sanjay, Chaya M David, G Savitha, J Rema, BK Ramnarayan
Department of Oral Medicine & Radiology, Dayananda Sagar College of Dental Sciences, Shavige Malleshwara Hills, Kumaraswamy Layout, Bangalore-560 078, India
|Date of Web Publication||1-Dec-2009|
C J Sanjay
Department of Oral Medicine & Radiology, Dayananda Sagar College of Dental Sciences, Shavige Malleshwara Hills, Kumaraswamy Layout, Bangalore - 560 078
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective : To evaluate and compare the efficacy of conventional and digital radiographic methods in the detection of simulated external root resorption cavities and also to evaluate whether the detectability was influenced by resorption cavity sizes. Methods : Thirty-two selected teeth from human dentate mandibles were radiographed in orthoradial, mesioradial and distoradial aspect using conventional film (Insight Kodak F-speed; Eastman Kodak, Rochester, NY) and a digital sensor (Trophy RVG advanced imaging system) with 0.7mm and 1.0mm deep cavities prepared on their vestibular, mesial and distal surfaces at the cervical, middle and apical thirds. Three dental professionals, an endodontist, a radiologist and a general practitioner, evaluated the images twice with a one-week time interval. Results : No statistical significance was seen in the first observation for both conventional and digital radiographic methods in the detection of simulated external root resorptions and for small and medium cavities but statistical difference was noted in the second observation (P<0.001) for both the methods. Conclusion : Considering the methodology and the overall results, conventional radiographic method (F-speed) performed slightly better than the digital radiographic method in the detection of simulated radiographic method but better consistency was seen with the digital system. Overall size of the resorption cavity had no influence on the performance of both methods and suggests that initial external root resorption lesion is not well-appreciated with both the methods as compared to the advanced lesion.
Keywords: Conventional radiography, digital radiography, simulated external root resorption
|How to cite this article:|
Sanjay C J, David CM, Savitha G, Rema J, Ramnarayan B K. Conventional and digital radiographic methods in the detection of simulated external root resorptions: A comparative study. J Indian Acad Oral Med Radiol 2009;21:67-71
|How to cite this URL:|
Sanjay C J, David CM, Savitha G, Rema J, Ramnarayan B K. Conventional and digital radiographic methods in the detection of simulated external root resorptions: A comparative study. J Indian Acad Oral Med Radiol [serial online] 2009 [cited 2020 Apr 8];21:67-71. Available from: http://www.jiaomr.in/text.asp?2009/21/2/67/57889
| Introduction|| |
External root resorption is a condition associated with a physiological or pathological process, resulting in loss of mineralized tissues like dentin, cementum and alveolar bone and is seen as a complication after dental trauma, transplantation, and orthodontic movement of teeth.  Usually, this pathology does not present any clinical signs and symptoms and radiography is the only means by which it can be detected. Its early detection is important for both diagnostic and therapeutic purposes. , However, since radiology is the most widely used method in clinical practice, it is important to better define its advantages and disadvantages, in order to obtain the most precise information from radiographs.
Currently, intraoral dental X ray film is available in three groups - D, E and F. Recently introduced F-speed film requires about 75% of the exposure of E-speed film and only 40% of that of D-speed.  With the introduction of digital intra-oral dental radiography the radiation dose can be decreased to one-third of conventional film-based radiography. , Digital sensors are either a charge-coupled device (CCD) or complementary metal oxide semiconductor active pixel sensor (CMOS-APS) or storage phosphor plates.  The CMOS-APS, unlike the CCD, can be manufactured in mainstream silicon foundries, allowing for reduced production costs. 
Several studies were carried out to compare conventional and digital radiography with respect to diagnosis of dental caries, periodontal bone loss and endodontics. But very few studies were carried out recently with respect to root resorption.  So the present study is an attempt to evaluate the efficacy of both conventional and digital intraoral radiographic methods in detection of simulated external root resorptions and also to evaluate whether the detectability was influenced by resorption cavity sizes.
| Materials and Methods|| |
A total of five dentate dry human mandibles were collected from the Department of Anatomy, Dayananda Sagar College of Dental Sciences. Thirtytwo normal teeth from five dentate mandibles were selected (eight incisors including both central and lateral incisors, eight canines, eight premolars and eight molars).
All the radiographs were taken in standardized procedure and processed by freshly prepared solutions by time and temperature method. Exposure time was standardized for digital radiography and conventional radiography using an aluminum step wedge The aluminum step wedge was placed in place of teeth in the positioning device [Figure 1] and radiographed at different exposure levels for both the systems. All the radiographs were randomly sequenced and presented to four oral radiologists. Based on the observations of the radiologists exposure timings were selected for individual tooth type at film speed 8 (exposure level) at 70 KVp and 8 mA.
The following equipments and instruments were used for the study:
- An X-ray machine (Trophy CCX digital) having fixed 70 kVp, 8 mA and 1.5-mm aluminum filtration.
- Kodak Insight (F-speed) X-ray films, Size 2 (31 x 41 mm) Eastman Kodak Co, Rochester, NY.
- Trophy RVG (Kodak) Access sensor, Size 1, Digital Intraoral radiography system; with 14 lp/mm; with minimum system requirement of 250 MB RAM, available, USB port and 500 mA.
- RINN film and sensor holders (anterior and posterior, Size 2 for film.)
- A positioning device [Figure 1] was made using plaster of Paris and modeling wax to place X-ray tube and the dentate mandible (teeth) parallel to the film and the sensor. A plastic container with water was used as soft tissue stimulant.
Three periapical radiographs of each tooth were taken in an orthoradial, mesioradial and distoradial aspect using conventional film [Figure 2] and a digital sensor [Figure 3] to rule out any periapical pathology. Then the teeth were extracted using a forceps and small cavities of size 0.7 were prepared using round burs on their vestibular, mesial and distal surfaces at the cervical, middle and apical thirds. Following preparation, each tooth was replaced in its alveolus and new radiographs were taken. The second set of radiographs were with cavity size extended to 1.0mm.Three dental professionals, an endodontist, a radiologist and a general practitioner were co-opted in the study to interpret and evaluate the radiographs of both the systems. Totally 360 cavities were to be detected for each size and each system. This was repeated the second time after a gap of one week, to verify intraobserver variability. All the observers were asked to detect the presence of root resorption cavities by two confident scores (as below), in the given radiographs by both systems.
Two point confident scores:
- Probably resorption,
- Definitely resorption.
All the observers were provided with separate evaluating sheets for detecting the number of resorption cavities on a particular radiograph of a particular tooth of interest. The conventional radiographs [Figure 2] were viewed on an X-ray viewer box with the help of a magnifying lens. The radiographs were mounted on a viewer with the rest of the viewer surface covered with black paper and viewed under dimmed background light. In digital radiographic system [Figure 2] the observers were instructed not to manipulate the digital images. To avoid adverse effects of zooming all radiographs were shown in their original dimensions. Then the results were analyzed statistically for number of cavities detected, considering the variables of method, size, angulation, observer, and also for the probable and definite cavities observed.
| Results|| |
No significant difference (>0.05) was noted in the detection of total cavities by digital methods for both the observations but significant difference (P<0.001) [Table 1] was noted for that of the conventional method between the two observations. Also, when comparisons were made between the methods, no significant difference (>0.05) was noted in the first observation whereas in the second observation significant difference (P<0.001) was observed between the two methods [Table 2].
No significant difference was observed for the detection of small and medium cavities between the methods in both the observations. But there was a significant difference (P<0.001)[Graph 1]-[Additional file 1] between the total number of small cavities detected in comparison with medium cavities by both the systems. (Conventional small 66.11%, medium 92.50%) (Digital small 82.50%, medium 66.66%).
There was a significant difference (P<0.001) in the proportion of cavities [Graph 2]-[Additional file 2] detected by orthoradial and mesioradial angulations as well as orthoradial and distoradial angulations. (Orthoradial: 82.15, Mesioradial: 73.00%, Distoradial: 74.00%).
Among the observers the general practitioner detected less number of cavities [Graph 3]-[Additional file 3] using the digital method in both the observations but no significant difference was observed in the conventional method. Z-test was used wherever the two proportions were to be compared. Chi square test was used where more than two proportions were to be compared. P-value was considered significant when it was <0.05.
| Discussion|| |
Several factors contribute to external root resorption like dental trauma, orthodontic tooth movement and transplantation of teeth.  With the recent advances both in conventional radiographic systems and digital image receptors, the clinician has access to precise information and added advantage of reduced radiation dose. 
In the present study the results of the first observation shows that the proportion of the resorption cavities detected by both the conventional (74.72%) and digital radiographic methods (74.40%) were found to be similar and no statistical difference is noted. Hence this study shows that both digital and conventional radiography perform equally well in the detection of simulated root resorption cavities. These results are in accordance with the studies of Eva Borg et al.,  Eva Levander et al.  . Borg et al. produced 1.2 mm diameter/0.6-0.9 mm depth defects on the tooth roots and compared the conventional radiographic (E-speed film) and digital images, using only orthoradial projections. Their results showed that both the film system and the CCD system had values greater than 75%, implying no significant differences between the conventional and digital radiographic methods. Levander et al, (Kodak Ektaspeed plus film) using only lower bicuspids in orthogonal and eccentric projections, found no differences between digital (48%) and conventional (49%) methods. 
However, in our study when comparing the first and second observation [Table 1] and [Table 2] we found a statistically significant difference (<0.001) in the proportion of resorption cavities detected by the conventional radiographs (79.31%) as compared to digital radiographs (74.64%). However, the results of the first and second observation combined gives slight edge to conventional radiography over digital radiography.
As in our study Westphalen et al.  also used F-speed with same size cavities where digital radiography (81%) performed better than the conventional (67%) but intraobserver variability was not considered and hence consistency was not tested in both the systems. In contrast to this in our study F-speed film performed slightly better than digital sensor in both the observations but, better consistency was seen with the digital radiography than with conventional radiography.
The number of small and medium cavities detected by both the methods were equal in both the observations. Neither of the radiographic techniques detected many of the small cavities but both the techniques were consistent in detecting the same proportion of cavities in both observations. This is in accordance with the study by Eva Levander et al.  In their study (using Kodak Ektaspeed) of small (digital (27%) conventional (29%)), medium (digital (65%) conventional (60%) and large (digital (75%) conventional (83%) cavities, found that the sensitivity of radiographic methods increased significantly with cavity size. Our results are in contrast with the study conducted by Westphalen et al.  in the detection of simulated external root resorption in which both the small and medium cavities were better observed with the digital method (small:72%, medium 89%) as compared to the conventional method (small 58%; medium 78%). A possible factor in this result could be the fact that the digital images were presented with a 36% enlargement in comparison with the conventional images, which was not the case in our study.
In the present study the teeth were radiographed in three different projections; Orthoradial, Mesioradial and Distoradial, to increase the number of observations. A significant difference (P<0.001) was observed between orthoradial and mesioradial; and between orthoradial and distoradial projections. In the second observation (Orthoradial: 75.63%, Mesioradial: 72.78%, Distoradial: 77.01%) a significant difference (P<0.01) (Graph II) was observed between mesiodistal and distoradial projections. Thus, it is also important to keep a record of the angulations with which the different radiographs are obtained for each patient, in order to replicate them in future examinations.
Considering both inter- and intraobserver variability analysis we can infer that the general dental practitioner is less consistent in the interpretation. This may be attributed to the possibility of lack of familiarity with the digital system. Lack of inter-observer agreement as well as large variations in intraobserver agreement in assessing root resorption has been reported. , This variability has been attributed to bias resulting from prior knowledge of the clinical data, variation in film density, equivocal radiographic findings resulting in an increased rate of false negative and false positive diagnoses and observer education, training and experience , . The results of this study should be considered preliminary because the lesions are simulated and not the actual resorption lesions. The model used often created a lesion with a well-defined round outline, possibly making lesion detection an easier task relative to the typical resorption lesion. In a clinical situation, the resorption lesions would be more diffuse and lesions could be more difficult to detect.
In conclusion, considering the methodology and the results of this study, it indicates both F-speed and the CMOS-APS technology performed equally well in the detection of simulated external root resorptions. Both have the advantage of cost-effectiveness and reduced radiation dose compared to their currently used counterparts. Hence both these methods can be considered for routine dental practice in the detection of external root resorptions. However, F-speed has an edge over the CMOS digital sensor because of the initial investment cost.
| Acknowledgements|| |
Authors wish to acknowledge the help received from Dr Manjunath M (MDS, Professor and Head, Department of Oral Medicine& Radiology, V S Dental College and Hospital, V V Puram, Bangalore), Dr B. Keshava Prasad (MDS, Professor, R V Dental College and Hospital, Bangalore), Dr Vishwas (BDS, Srinivasa Dental Clinic, Bangalore), Dr Rachna Kaul, Dr Shilpa P S (Postgraduate Students, Department of Oral Medicine& Radiology, Dayananda Sagar College of Dental Sciences, Bangalore) and Mr Sunil Joshi (Kodak Inc..).
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]