|Year : 2019 | Volume
| Issue : 4 | Page : 339-345
Assessment of linear measurements with intra oral grid on intra oral periapical image – A comparison of digital and conventional film images using bisecting angle and paralleling techniques
K Roja Reddy1, Ramesh Tatapudi1, R Sudhakara Reddy1, C Naresh Kumar2, T Navya Teja3, G Swathi4
1 Department of Oral Medicine and Radiology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
2 Periodontology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
3 Department of Oral Medicine and Radiology, CKS Dental College, Tirupathi, Andhra Pradesh, India
4 Department of Oral Medicine and Radiology, Anil Neerukonda Institute of Dental Sciences, Visakhapatnam, Andhra Pradesh, India
|Date of Submission||07-Dec-2019|
|Date of Acceptance||22-Jan-2020|
|Date of Web Publication||03-Mar-2020|
Dr. K Roja Reddy
Department of Oral Medicine and Radiology, Vishnu dental college, Bhimavaram, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The success of various treatments protocols depends on pre-operative diagnostic aids such as radiographic assessment with linear measurements, in such scenario radiographic grid with its unique design aids like a scale for image analysis on intraoral periapical radiograph. Hence, the intra oral grid is a simple and accurate way of measuring objects, and another advantage is to overcome various magnification errors associated with measurements. So, the present study was designed to know its accuracy in assessing the linear measurements. Materials and Method: The study sample comprised a total of 40 subjects, which were categorized into four groups. A total of 240 exposures were taken, where each patient was subjected to six radiographs, of which two are conventional intraoral periapical radiographs without grid, and two are conventional intraoral periapical radiographs with grid by bisecting and paralleling technique and another two radiographs are taken by digital CMOS sensor with intraoral periapical grid in all four groups. The measurements were performed on the radiographs using scale and divider and in case of radiograph with the grid by counting the grid lines from specific points. Results: The results of the study revealed on comparison of conventional and digital radiographs with and without a grid in both bisecting and paralleling technique in all the four groups, there was a statistically significant difference noticed with digital radiography compared to the conventional method in assessing the measurements with the grid with P value <0.005. Similarly, paralleling technique showed a significant difference in its mean measurement values in all the four groups compared to bisecting angle technique in both conventional and digital methods in case of usage of grid. Conclusion: Intraoral grid was used as a scale in the instances where the exact size of various anatomical structures and pathologies cannot be determined visually in radiograph and even in cases of distortion; this can be used for standardization.
Keywords: Bisecting angle technique, conventional and digital image, intraoral grid, IOPA, linear measurements, paralleling technique
|How to cite this article:|
Reddy K R, Tatapudi R, Reddy R S, Kumar C N, Teja T N, Swathi G. Assessment of linear measurements with intra oral grid on intra oral periapical image – A comparison of digital and conventional film images using bisecting angle and paralleling techniques. J Indian Acad Oral Med Radiol 2019;31:339-45
|How to cite this URL:|
Reddy K R, Tatapudi R, Reddy R S, Kumar C N, Teja T N, Swathi G. Assessment of linear measurements with intra oral grid on intra oral periapical image – A comparison of digital and conventional film images using bisecting angle and paralleling techniques. J Indian Acad Oral Med Radiol [serial online] 2019 [cited 2020 Jul 2];31:339-45. Available from: http://www.jiaomr.in/text.asp?2019/31/4/339/279862
| Introduction|| |
Oral and maxillofacial radiology is the specialty of the dentistry concerned with performance and interpretation of diagnostic imaging used for examining the craniofacial, dental, and adjacent structures, which seems to be rising day by day with a new era of technologies and advancements. Even though, with the innovation of variously advanced imaging modalities in dentistry, an intraoral periapical radiograph (IOPA) is most often prescribed as it enables us to visualize the entire tooth and its surrounding structures with good image quality. So, it serves as a prime source of investigations right from diagnosis, during various treatment procedures, evaluation of prognosis and necessary components of comprehensive patient care. The success of various treatments protocols depends on assessment of pre-operative radiographic linear measurements like working length determination during root canal treatment and to assess the height of alveolar bone during implant placement, to assess the bone loss during periodontal surgeries, and for accurate measurement of a pathologic lesion, is important to allow a follow-up regarding the regression of a lesion, although the essence of the paralleling technique could reduce the number of distortions theoretically, there are difficulties in performing the maneuver. The limitation with the bisecting angle technique is that lack of expertise may lead to more chance of image distortions like elongations and foreshortenings. To surmount the distortions during measurements is very crucial factors, because in such scenario radiographic grid with its unique design aids like a scale for radiographic analysis on intraoral periapical radiograph, and in the condition where accurate measurements are compromised in radiograph visually, can easily determine without hampering the image quality by using intra oral grid. The soul of the intraoral X-ray grid is similar to size of the regular periapical film, when superimposed along with the film and exposed the film shows an anatomic structure with grid lines which is 1 mm apart running both lengthwise and every fifth millimeter, is accentuated by a heavier line to make easier the reading of finished radiograph and by usage of these grids help in surmount the magnification errors associated with radiographic techniques because the distance between grid line increases on elongations and decrease on foreshortening and another advantage is less expensive as it can be sterilized so reused. Given the paucity of the literature and dearth in the availability of existing data, the present study has been undertaken to know its accuracy in assessing the linear measurements on both intraoral periapical film and digital image receptor using bisecting angle and paralleling technique.
| Materials and Method|| |
The radiographic comparative study was carried out among 40 patients who are selected from outpatient department (OPD). The study protocol was approved by the Institutional Ethical Review Board and informed consent was obtained from each participant. A total of 40 subjects were divided in to four groups 10 patients in each group: Group 1: Root canal length was determined, Group 2: Interdental bone loss was assessed, Group 3: Height of edentulous space was assessed and Group 4: In fourth group size of periapical pathology was assessed. A total of 240 exposures were taken in all four groups. Each patient was subjected to six radiographs of which two are conventional IOPA without grid, two are conventional IOPA with grid by using bisecting and paralleling technique, and another two radiographs are taken by digital RVG sensor with IOPA grid by using bisecting angle and paralleling technique. Patients who are referred for routine radiographic investigations were included in the study, and patients with developmental defects of bone and teeth, who are not willing to take the radiograph and with any severe pathology in the region of periapex, which may hamper the image qualities were excluded from the study. All the participants were explained about the design of the study, and a written consent form was signed by the subjects. All the subjects recruited for the study were subjected to thorough oral examination and case history were recorded in a specially designed proforma and informed consent from the participant was taken before the radiographic examination. During the procedure for conventional radiography, the intraoral radiographic unit operated at 70 kvp and 6 mA with a focus film distance of approximately 35 cm was used. The IOPA film used were Kodak® Ekta speed film, number 2 of size 41 × 31 mm radiograph for indicated tooth was taken by fixing IOPA grid with the radiographic film within the plastic sleeve which fits compactly on all sides as the film and grid won't be mobile therefore the chances of distortion of image can be minimised and appearance of grid lines were parallel without missing lines, and later the radiographs were exposed with and without grid at a time by both bisecting and paralleling technique, and later processing of the film was done manually by using time-temperature method. Similarly for digital radiography for the same patient a series of digital images were taken by radio visio graphy (RVG) of Kodak® 5000 system and Vatech® dental X-ray unit operated at 70 kvp and 8 mA with easy dent viewer software for obtaining images. For better standardization, in the present study, we preferred to use the paralleling position indicating device and further for better standardization, a specially prepared customized acrylic stent was fabricated using elastomeric putty impression and acrylic resin which act as aiming ring to keep the tube cylinder stable and parallel to the sensor [Figure 1] and [Figure 2]. To ensure maximum hygiene for each patient film, sensor, and grid were covered with disposable sleeves and placed in the patient's mouth in the area of tooth to be expose by both bisecting and paralleling technique simultaneously. In bisecting technique patient was ask to hold the film and for paralleling technique in digital radiography paralleling holder are used and obtained images were saved in the system after adjusting required contrast, resolution, and enhancement. The following parameters were assessed in each group and measurement was recorded in radiographs manually, standardization was followed in the study during measurements among all the six radiographs of each patient were measured on the same side either mesial or distal. In first group root canal was assessed on radiographs the measurements were taken from cusp tip to radiographic root apex [Figure 3]a and [Figure 3]b. In second group interdental bone loss was assessed from cemento-enamel junction to crest of alveolar bone [Figure 4]a and [Figure 4]b. In the third group, the height of edentulous space was assessed from the crest of alveolar bone to nearby anatomical landmarks in case of maxilla maxillary sinus and in case of mandible mandibular canal and mental foramen are taken as standard landmarks for measurement [Figure 5]a and [Figure 5]b. In fourth group sizes of periapical pathology like periapical granuloma, cyst, and abscess were assessed the measurement from longest vertical length of the pathologies measured on radiographs with and without grid by using bisecting and paralleling technique [Figure 6]a and [Figure 6]b. Grids were used in an alternatively for using scale divider directly, the lines were counted, and every fifth line was taken as a basis of its thickness, hence it helps in evaluation of number of lines from specific points on the radiograph and all the measurements were taken in the unit of millimetres. Similarly, in RVG radiographic measurements are taken as same as conventional radiographs by counting the number of grid lines from specific points in the radiograph in all the four groups.
|Figure 1: Film holders, intra oral periapical grid, scale, divider, marker|
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|Figure 3: ( a) Intra oral periapical radiograph without grid depicting the working length. (b). With grid depicting the working length|
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|Figure 4: (a) Intra oral periapical radiograph without grid depicting the interdental bone loss. ( b) With grid depicting the interdental bone loss|
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|Figure 5: (a) Intra oral periapical radiograph without grid depicting the edentulous space. (b) With grid depicting the edentulous space|
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|Figure 6: ( a) Intra oral periapical radiograph without grid. (b) With grid depicting the size of periapical pathology|
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| Results|| |
[Table 1]. Overall distribution of study sample according patients, radiographs, type of radiographs technique. [Table 2]. Shown there was no statistical significant on comparison of linear measurement with and without usage of grid in Conventional method using Paralleling technique in all the four group. [Table 3]. Shown there was no statistical significant on comparison of linear measurement with and without usage of grid in conventional method using bisecting angle technique in all the four groups. [Table 4]. Shown on comparing the average linear measurements in millimeters with the usage of grid in conventional and digital method using paralleling technique in all the four groups, there was a statistical significance (P < 0.05), whereas digital with grid shows more measurements in all the four groups. [Table 5]. When compared the average linear measurements in millimeters with usage of grid in conventional and digital method using bisecting angle technique in all the four groups. It was observed that there was a statistical significance (P < 0.05), whereas digital with grid shown more measurements in all the four groups. [Table 6]. Shown there was no statistical significant on comparison of linear measurement with usage of grid in conventional method using bisecting and paralleling technique in all the four group. [Table 7]. Shown there was no statistical significant on comparison of linear measurement without usage of grid in conventional method using bisecting and paralleling technique. [Table 8]. Thus, comparing the average linear measurement in millimeters with the usage of a grid in the digital method by using paralleling technique and bisecting angle technique, there was statistical significance (P < 0.05) were observed, whereas digital with grid in paralleling technique revealed more measurement in all the four groups.
|Table 1: Overall distribution of study sample according to the number of Patients, number of radiographs, type of intra oral radiographic Method and techniques performed|
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|Table 2: Comparison of linear measurement with and without usage of grid in Conventional method using Paralleling angle technique|
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|Table 3: Comparison of linear measurement with and without usage of grid in Conventional method using Bisecting angle technique|
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|Table 4: Comparison of linear measurement with usage of grid in Conventional and Digital method using Paralleling angle technique|
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|Table 5: Comparison of linear measurement with usage of grid in Conventional and Digital method using Bisecting angle technique|
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|Table 6: Comparison of linear measurement with usage of grid in conventional method using bisecting and paralleling technique|
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|Table 7: Comparison of linear measurement without usage of grid in conventional method using bisecting and paralleling technique|
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|Table 8: Comparison of linear measurement with usage of grid in Digital method using bisecting and paralleling angle technique|
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| Discussion|| |
Radiography is a primary investigating procedure used in the dental practice for the purpose of radio diagnosis in dental procedure and observing anatomic structures and pathologies in the teeth and jaw. IOPAR is still a gold standard radiographic tool for observing periodontal structures. So, it serves as a prime source of investigations right from diagnosis, during various treatment procedures, evaluation of prognosis and necessary components of comprehensive patient care. Measurement of radiographs is especially significant during various dental treatments like assessing the root canal length, to assess the interdental bone loss, where precision is a factor influencing the success of the treatment., Almost all the radiographs had distortions in the form of elongations, although the paralleling technique could reduce the amount of elongation. Previous studies have shown that radiology does involve some projection errors and may not give an accurate estimation of the length, but some studies have incorporated certain techniques and made these errors insignificant., Some of these techniques include the use of an IOPAR grid and a cone beam indicating device to ensure parallelism in the radiography technique. So an attempt has be taken in the present study to assess the amount of infinitesimal distortions in the radiographs by both bisecting angle and paralleling technique using guiding tool like intra oral grid which gives precise measurements, to know its accuracy in assessing the linear measurements on the radiographs a comparison of radiographs with grid and without grid on the radiographs in both bisecting and paralleling technique., The intra oral grids used in the present study is different from extra oral grids, similar to the size of a regular periapical film, Intra oral grids are made up of thick and thin wire of copper, when superimposed along with the film and exposed the film shows anatomic landmarks with grid lines which are 1 mm apart running both lengthwise, width wise and every fifth millimeter is accentuated by a heavier line to make easier the reading of finished radiograph. To overcome the clinical problems of distortions and to enable an accurate measurement on a radiograph, radiographic grids were useful. So, a thinner linear grid on intraoral periapical radiography act like a scale which gives an accurate measurement even in case of distortions and also in the instances where the exact size of various anatomical structures and pathologies cannot be determined in radiograph visually can easily determine without hampering the image quality. So, the grid is a simple, and accurate way of measuring objects and it can be sterilized and it is economical. As per the literature, the number of studies was less regarding the comparison of linear measurement using grid and without grid on the intraoral periapical image by comparing conventional and digital method using bisecting and paralleling angle technique. So, in the present study after subjecting to statistical analysis, a total of seven comparisons were done in all the four groups. Among all the comparisons, digital radiography was statistically significant when compared to conventional method in assessing the measurements with the grid. The reason would be due to stiffness of sensor compared to conventional film where there is a chance for bending of the film and distortion is more compared to digital image receptor, which is well witnessed in the present study, similarly paralleling technique showed a significant difference in its measurement values in all the four groups compared to bisecting angle technique which is a known fact and was witnessed even on using the intra oral grid. It could be because of XCP paralleling gridded technique, where there is standardization of the tube and film placement with grid in relation to the teeth, therefore resulting in less chance of distortions on the radiograph taken in paralleling angle technique which was a proved in the present study. The results of the present comparison in case of assessing the root canal length are in agreement with a study carried by Larheim et al. where he concluded that using grid with measuring lines is more accurate than other clinical methods commonly used for determination of tooth length. The results of the present comparison in case of assessing interdental bone loss are in accordance with a study carried by Soumi J et al. and concluded that millimeter grid acts like a scale even in case of radiographic distortion even on taking the radiographs with paralleling angle technique. The results of the present comparison in case of assessing the alveolar bone are in accordance with study carried by PerezF et al. and concluded that with the help of grid accurate measurement can be obtained in case of assessing the bone loss by bisecting angle technique which act like a scale similar to present study. The results of the present comparison was not in accordance with the study carried by Mouyen et al. and concluded that the resolution of RVG was inferior to conventional radiographs under similar exposure parameters, but in accordance with the study carried by Horner et al. concluded that RVG was useful in delineating anatomical structures and periapical tissues and concluded that the minimal inherent distortion of the RVG image was a distinct advantage over conventional film. The results of present comparison in case of assessing the periapical pathologies are in accordance with study by J Forsberg et al. where he assessed the periapical radiolucencies by bisecting and paralleling angle technique and concluded that no significant differences between the size of the lesion as recorded by two techniques, when correctly adjusted the bisecting and paralleling technique shows similar diagnostic results.
| Conclusion|| |
Within the confines of the present study, it was established that grids are not used in IOPAR with film or intraoral digital sensors as none of the studies were conducted before these is the initial and prime study. So, to end with the effort may be a value that intra oral periapical radiograph with intra oral grid showed an accurate measurement in case of digital radiographs which were taken in paralleling technique, the reason would be conventional radiographs may have a chance of bending and paralleling technique was standard radiographic technique compared to bisecting angle technique which is most commonly used.
Therefore, based on the study results linear dimensions of root canal treatment was found to be accurate in both digital and paralleling technique by using grids the all the four groups. Hence, our results demonstrate using grids in both paralleling and digital technique; it was useful for assessing linear dimensions in day-to-day clinical scenario such as, root canal length, interdental bone loss, edentulous space, and any periapical pathology. To strength this conception, further studies should be done on more radiographs with greater sample size, within the confines of the study grid can be advised to use in clinical practice as a guiding tool for assessing the linear measurements during various dental procedures would make it useful as future guiding and radiographic measurement tool. Further studies in comparison with intra surgical measurement would aid in knowing its accuracy in clinical practice.
Department of Oral medicine and Radiology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]