|Year : 2015 | Volume
| Issue : 2 | Page : 129-133
Influence of X-ray beam angulations on the detection of horizontal root fractures
Josue Martos1, Francini Santos Silva2, Isadora Dalmaso Poglia2, Melissa Feres Damian1, Luiz Fernando Machado Silveira1
1 Department of Semiology and Clinics, University Federal of Pelotas, Pelotas; Faculty of Dentistry, University Federal of Pelotas, Pelotas, Brazil
2 Faculty of Dentistry, University Federal of Pelotas, Pelotas, Brazil
|Date of Web Publication||20-Apr-2015|
Department of Semiology and Clinics, College of Dentistry, Gonçalves Chaves st. 457 Pelotas, RS 96015-560
Source of Support: None, Conflict of Interest: None
Aims: The aim of this study was to evaluate the variation of vertical angle for detection of fractures. Materials and Methods: Twenty-five (25) single-rooted premolar teeth were divided into two groups, fractured teeth (n = 15) and non-fractured teeth (n = 10). Artificially fractured teeth were classified according to location, number of fragments, and direction of fracture line: Horizontal, oblique, or complex. The tooth fragments were juxtaposed with cyanoacrylate, and the specimens (fractured and non-fractured) were placed individually in the dental alveolus of a human jaw with the aid of silicone rubber impression material and submitted to eight periapical radiographs in a digital sensor with a vertical range of 10 degrees (−40, −30, −20, −10, 0, +10, +20, +30). Three examiners evaluated the characteristics of the fractures and their correlation with the radiographic diagnosis (perceived or not) by varying the vertical angle. Statistical Analysis: Descriptive analysis was performed through the analytical comparison and Kappa test inter-examiner. Results: Among the three examiners, inter-examiner Kappa value was 0.536. The radiographic identification of root fracture in the 15 prepared samples was 60% (nine) at angle 0, and at the angles of +10, −10, and −20, it was less than 50%. Conclusions: Multiple radiographs with variations of vertical angle are fundamental to facilitate the diagnosis of horizontal root fractures in premolars.
Keywords: Dental trauma, diagnosis, root fracture
|How to cite this article:|
Martos J, Silva FS, Poglia ID, Damian MF, Silveira LM. Influence of X-ray beam angulations on the detection of horizontal root fractures. Saudi Endod J 2015;5:129-33
|How to cite this URL:|
Martos J, Silva FS, Poglia ID, Damian MF, Silveira LM. Influence of X-ray beam angulations on the detection of horizontal root fractures. Saudi Endod J [serial online] 2015 [cited 2020 Sep 19];5:129-33. Available from: http://www.saudiendodj.com/text.asp?2015/5/2/129/155452
| Introduction|| |
Traumatic injuries to the dento-alveolar structures are common, but horizontal root fractures are uncommon lesions, with a prevalence of 0.5-7% among all injuries that occur in permanent teeth. , Root fractures, like any injuries to the hard tissues, require for correct diagnosis an accurate method to establish the fracture's location and the extent of therapeutic possibilities.  To detect horizontal fractures, the vertical angle should be changed; the central beam should focus on the fracture plane and be perpendicular to the film.  When examining a probable fracture line, two additional periapical radiographs (PAs) should be taken: One with a positive increase in angle of approximately 15 degrees from the original position and another with a negative angle of 15 degrees in relation to the original position. , The International Association of Dental Traumatology recommends that at least one intraoral radiograph should be taken in all cases with a complicated or uncomplicated crown fracture of permanent teeth.  For suspected or clinically confirmed root fracture, four different angulations should be performed. 
Conventional PAs are the most used because of their convenience for providing images that can help the professional in solving a large number of cases; however, the limitation in visualization using these images in some regions and their restriction to two dimensions can hinder planning in specific cases.
In this context, cone-beam computed tomography (CBCT) provides a view of the desired area in several orthogonal planes. , Despite the possible advantages of using this method, CBCT has some limitations, such as the high cost of equipment and the possibility of image changes due to metal objects, as well as a higher radiation dose, implying that its use should not be prescribed until after conducting a precise clinical examination. ,
The radiographic image is one of the main tools to visualize anatomical and pathological characteristics.  Moreover, images obtained with the use of orthoradial angles may result in the overlap of normal and abnormal structures, hindering their correct interpretation. Thus, there may be occasions where the variation in angle will be beneficial because it will provide additional information that may not be visible on radiographs taken without this variation. 
The stress caused by forces that affect the maxillary premolars is concentrated on the buccal and lingual walls of flattened roots, whose channels are elliptical, providing a greater chance of fracture,  yet the mandibular bone density could be a factor difficulty in the visualization of root fractures during routine examination.
The hypothesis tested is that diagnostic radiography alone is not enough to view different types of root fractures, wherefore the main objective of this study was to evaluate the influence of X-ray beam angulations on the detection of horizontal mid-root fractures in permanent premolars.
| Materials and methods|| |
Twenty-five human, single-rooted teeth with complete root formation, obtained from the human teeth bank maintained by the Faculty of Dentistry at Federal University of Pelotas, Pelotas, RS, Brazil were used. All teeth were cleaned with periodontal curettes and sterilized in an autoclave at 120 o C for 20 minutes (Dabi Atlante, Ribeirão Preto, SP, Brazil), hydrated in distilled water for 48 hours, and subsequently stored in a 10% formalin solution. In addition to the inclusion criteria described above, the exclusion criteria were the rejection of samples with extensive coronary destruction, root dilaceration or root curvature above 15%.
Twenty-five (25) single-rooted premolar teeth were divided into two groups, fractured teeth (n = 15) and non-fractured teeth (n = 10). The non-fractured premolars were separated to form the control group.
The preparation of artificial fractures in this study was performed using a mechanic lathe under pressure with the tooth. Then a transverse load was applied on the buccal surface with the aid of a hammer to obtain the fracture. The coronal portion, before the application of the load, was protected with a thick cloth.
The fractured teeth were then classified according to location of fracture, number of fragments generated, and the type of fracture line: Horizontal, oblique, or complex [Figure 1].
|Figure 1: Types of fractures applied in this investigation. Horizontal (a), oblique (b), and complex (c)|
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Fractured specimens (teeth) were identified numerically and stored individually in Eppendorf tubes for subsequent radiographic evaluation. The fragments of each specimen were repositioned and fixed/bonded with a cyanoacrylate gel (SuperBonder, Loctite, SP, Brazil) to simulate a non-displaced fracture manipulation of the teeth during the radiographs.
The specimens were placed in a human jawbone. The specimen was secured using a silicone impression material (Oranwash L, Zhermack, Rovigo, Italy) with an opacifier (Calcium carbonate, Labsynth, São Paulo, Brazil) in order to simulate the radiographic appearance of anatomy [Figure 2].
|Figure 2: (a) Occlusal and lingual (b) aspect of the dental alveolus of a human jaw. (c) Simulation of the appearance of the tooth specimen positioned. (d) Lingual view|
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With the specimens prepared and adjusted in the alveolus, the radiographs were obtained by using radiographic equipment (Spectro 70x, DabiAtlante, Ribeirãão Preto, SP, Brazil). The mandible was positioned parallel to the digital sensor [Figure 3].
|Figure 3: Sequence radiographic with the different angles used in this investigation|
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Eight radiographs were taken of the control samples of non-fractured teeth (n = 10) and fractured teeth (n = 15).
A VistaScan digital X-ray sensor (Dόrr Dental AG, Baden-Wόrttemberg, Germany) was used. Radiographic images were captured with DBSWIN software (Dόrr Dental AG, Baden-Wόrttemberg, Germany) for each sample by generating images at very high resolution. The software allowed the exportation of images as JPG files.
For radiographic evaluation, three different examiners, specialists in different areas (radiology, endodontics and periodontics), all of them with a minimum of ten years of clinical experience and serving as professors, conducted the analysis of digitized radiographs. These digitized radiographs were arranged randomly and without knowledge of the presence or absence of fractures. The non-fractured samples used as the control group were randomly distributed among the remaining 120 radiographs of the samples that had fractures. All radiographic images were placed into slide presentation software (PowerPoint, Microsoft Corporation, USA) and distributed to the examiners to indicate the presence or absence of root fracture.
The data regarding the fractures and their correlation were tabulated and inserted into statistical software (Statistical Package for Social Sciences [SPSS] Inc., Chicago, USA) for Windows version 8.0. The inter-examiner Kappa test was used to compare examiners' assessments.
| Results|| |
The frequencies of data regarding the presence or absence of root fractures, in addition to the comparison of interpretations provided by the inter-examiner Kappa scores, are shown in [Table 1] [Table 2] [Table 3].
|Table 2: Evaluators' average detection rate of root fractures in the fractured samples (n=15) according to the degree of vertical angle (n/total of the samples) |
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|Table 3: Details of the type of fracture line (horizontal, oblique, or complex) observed in the visible and non-visible samples according to the degree of vertical angle (n/total of the samples) |
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Among the three examiners, an inter-examiner Kappa value of 0.536 was obtained, which means a moderate value of agreement on the scale of interpretation, according to Landis and Koch. 
Regarding the identification of radiographic root fracture in the fifteen specimens prepared for such evaluation, 60% or nine samples of the radiographs taken at an angle of 0 degrees were detected clearly. The specimens with fractures that were detected at 0 degrees were located mostly at the apical level. Of these fractures, four were oblique, three were horizontal, and two presented complex or multiple fractures. The angles of +10 o , −10 o , and −20 o yielded less than 50% radiographic visibility of fractures.
| Discussion|| |
The results provided in this study reflect the importance of multiple radiographic investigations in the diagnosis of root fractures. The obscurity of fractures noted in some radiographs in the bisectrix technique can be resolved with variation of the vertical angle.
Despite the direction and type of the root fractures, which does not correlate with the most common mechanism and cause of fractures in posterior teeth, it was possible to envision a direct relationship with a real situation of a frontal trauma (i.e. direct blow with the fist or other objects, car accidents).
The hypothesis tested was accepted because it was not possible to evidence root fractures with only one periapical radiograph in all tested samples. In 40% of the radiographs submitted at a standard angle (parallelism technique), the evaluators found no evidence of fracture. However, with variation of the vertical angle (lower or higher angulations) when examining these same samples (except two), the evaluators were able to detect radiographic fractures. All samples from the control (non-fractured) group were identified by the three blinded evaluators as not being fractured.
In cases of root fractures, two factors should be considered in relation to the radiograph: The direction of the X-rays in relation to the fracture and the fracture plane incline relative to the film.  Damaa et al.  found that only one radiograph is insufficient to diagnose all types of fractures. Degering  and Molina et al.  state that a variation of 15°, positive or negative, relative to the original radiograph position, would be enough. The angulation of the cone in the radiographic detection of a horizontal root fracture is critical. In order to successfully diagnose a horizontal root fracture, the cone must be between 20° and +10°. Therefore, if one suspects a horizontal root fracture, it is a good idea to take multiple radiographs. 
It is imperative to examine other radiographic signs as auxiliaries in the diagnosis of root fracture, such as thickening of the periodontal space, radiolucent lines on fracture traces, radiopaque areas representing the superposition of fractured walls, and even the presence of tooth displacement. 
Although the margin of lacking visualization can be considered small or discreet, in the clinic, not identifying such fractures can have disastrous results, contributing to inaccurate diagnosis and insufficient treatment. A root fracture with a horizontal direction and located in the middle third and/or apical has a better prognosis compared with a vertical fracture, which yields a less reliable prognosis. ,
It is worth highlighting one limitation of the present study with respect to the number of specimens employed. Thus, future studies should increase the number of specimens and other radiographic images in order to make more robust comparisons. The objective of using a regular radiographic protocol was to approximate a clinical reality in the first contact with a traumatized patient. The use of a variation in vertical angulation in radiographic procedure in cases of suspected dental trauma could make a more concrete diagnosis of a horizontal fracture easier.
Even though root fractures can be clinically and radiographically misdiagnosed or undetected because of anatomical features or superimposition of dental structures, the horizontal root fracture is easier to detect than the vertical when conventional PAs are used. This is due to that most of the vertical root fractures are difficult to see.  The accuracy of detecting an artificial vertical root fracture was compared with conventional PAs by Hassan et al. They reported an overall higher accuracy for CBCT for detecting vertical fracture than PAs. Similar findings were reported by Wang et al. and Kajan et al. In the other hand, Kamburoglu et al. reported no significant differences between CBCT and conventional film radiography in detecting simulated horizontal root fracture. Therefore, in case of a suspected root fracture, PAs with at least two angles can be performed, especially if there isn't an available CBCT. If the diagnosis remains questionable or doubtful, then CBCT should be used in order to increase the likelihood of detecting vertical root fractures.
The clinical recommendation based on the results of the study is that variation of the vertical X-ray beam angulations provides the highest probability of detecting fractures and should therefore be used in radiographic diagnostics in suspected infra-alveolar root fractures in mandibular premolars.
| Acknowledgement|| |
To Professors Sergio Lϊcio Lopes e Luis Eduardo Rilling Nova Cruz for their assistance in the radiographic evaluation.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]