The Basics of Radiography in Dentistry
Radiography refers to the imaging technique that depends on the use of x-rays for viewing the internal forms of a biological object (USFDA, 2018). The process of radiography encompasses creation of a beam of electromagnetic radiation, or x-rays that are produced from a generator and projected towards the object, currently being viewed (Dance, et. al., 2014). The discovery of x-rays is credited to Wilhelm Röntgen, the German physicist, who was the first person to systematically conduct a study on its functions. X-rays were found to get emanated from discharge tubes, commonly known as Crookes tubes, which produced free electrons by residual air ionization. Radiological cars were developed in 1914 for supporting the soldiers injured during World War 1.
Radiographic techniques are used in dentistry by professionals to help evaluate oral health by detecting the development or progress of a dental disease or treatment. Assessment of the dental and periodontal tissues through radiography is a vital component of the detailed oral examination and serves as a diagnostic tool (Acar & Kamburo?lu, 2014). Exposure of radiation linked with dentistry procedures signifies a small part to the total exposure from each of the sources (Okano & Sur, 2010). The digital period of dental radiography started in 1988 with RVG, radiovisiography. The film-like sensor was first presented in 1994. Radio visiography (RVG) is a direct digital method of radiography. It is utilized for recognizing carious lesions, evaluating root lengths, and in diagnosing periapical pathology and root fractures (Deepak, et al., 2012). Apart from the reduction in radiation exposure, digital radiography also facilitated effective communication of electronic data, offers portability, and eradicates the environmental load of silver and other chemicals utilised to create X-rays (Stelt, 2005).
Dental x-rays play an important role in visualising dental anatomy, surrounding structures and any pathology in endodontic diagnosis and treatment planning (Patel et al., 2015). Historically, intra-oral peri-apical radiographs have been the most accurate diagnostic aids that are used by endodontists for diagnosing diseases that affects the mandible and maxilla (Patel at al. 2009).
Several imaging techniques are available to endodontics as diagnostic aid. Ultrasound (US) and Magnetic resonance imaging (MRI) are utilized to assess normal and diseased states of the bones and soft tissues of the oral and maxillofacial area (Senthil Kumar & Nazargi, 2010).
Computed tomography (CT) is another significant imaging technique used in head and neck anomalies (Dammann, et. al., 2014) . CT is used to image the maxillo-facial structures, including facial skeleton (Dammann, et. al., 2014) A CT scan uses computer-processed combinations of several X-ray measurements taken from different angles to generate cross-sectional (tomographic) images of particular regions of a scanned item, enabling to view inside the item without cutting. CT generates data that can be manipulated in order to show different bodily structures on the basis of their capability to absorb the X-ray beam. In previous times, the images that were produced were in the axial or transverse plane, perpendicular to the long axis of the body, but in current times the volume of data is formatted in several planes or even as volumetric (3D) representations of structures. Apart from the medicine, CT is also used in other fields, such as nondestructive materials testing, archaeological uses, etc. Historically, in endodontics CT imaging was rarely used, although it has been documented in literature(Scarfe, et. al., 2009).
Digital Radiography in Dentistry
Cone-beam computed tomography (CBCT) is an instrumental development for assessment of endodontic cases. It is also a digital imaging technique, which is particularly developed to generate exact 3-D information of the maxillofacial skeleton, 3-D images of the teeth and the adjacent tissues. CBCT is a method which includes X-ray computed tomography where the X-rays are divergent, forming a cone (Scarfe, et. al., 2006). During dental or orthodontic imaging, the CBCT scanner rotates around the person’s head, obtaining up to around 600 separate images. For interventional radiology, the patient is positioned offset to the table so that the region of interest is centered in the field of view for the cone beam. A single 200 degree rotation over the region of interest acquires a volumetric data set. The scanning software gathers the information and reconstructs it, generating what is referred to as digital volume composed of three-dimensional voxels of anatomical data that can then be manipulated and visualized with specified software (Hatcher, 2010). CBCT has several similarities with conventional (fan beam) CT but there are various differences, specifically for reconstruction. CBCT is viewed as the gold standard for imaging the oral and maxillofacial area. CBCT has become increasingly important in treatment planning and diagnosis in implant dentistry, ENT, orthopedics, and interventional radiology (IR), among other things. Due to the increased access to such technology, CBCT scanners have become a common tool in dentistry, like in the fields of oral surgery, endodontics and orthodontics. Integrated CBCT is also a significant method for positioning the patient and verification in image-guided radiation therapy (IGRT).
A new invention, commonly known as computed tomography was developed in the year 1972 that brought about major transformation in diagnostic medicine. No significant changes were observed in geometry for imaging dentition since 1896. The very first publication of CT technology in management of endodontic problems was carried out by Tachibana & Matsumoto (1990). Although CT technology had been around for quite some time, the recognition of CT in endodontic use has been delayed due to high radiation dose for a small area, relatively poor resolution of images generated and high cost of purchasing the CT unit. The technique of CT scan progressed to CBCT; a method found by the British engineer Godfrey Hounsfield in 1967 (Bhattacharyya, 2016). CBCT technology has overtaken CT scans in management of Oral and maxillofacial problems.
CBCT or cone beam computed tomography; the medical imaging technique based on x-ray computed tomography has gained attention in the recent years. This technique was introduced in 1996 in Europe by QR s.r.l. and in 2001 the first CBCT machine New Tom 9000 was installed in US market. CBCT has numerous potential advantages for dental imaging, compared with conventional CT scans. Some of the benefits are; the ability to reduce the field of view, thereby reducing the size of irradiation (Scarfe et.al .,2016), image accuracy as the CBCT voxels (a value on a regular grid in three-dimensional space) can be extremely low, producing high quality resolution images, reduced scan time compared to conventional CT (White & Pharoah, 2018), effective dose reduction (Ludlow et.al.,2007), reducing image artefacts by use of suppression algorithms in the software (Cohen et.al. 2002). CBCT started to appear in research journals of dentistry after 2 years of introduction of 3D dental software in dentistry by Columbia Scientific Inc. (Orentlicher, et.al., 2012) . When dental professionals started using CBCT in dentistry, they found enhanced clarity of structures, anatomy and recognition of oral pathology (Scarfe, et. al., 2009). There was a clear distinction of individual structures and its relationship with adjacent anatomical structures (Shukla, et.al., 2017). CBCT has been proven as a ground-breaking invention as it simplified the process of decision-making and eased the detection of defects in bony structures from several angles (Shukla, et.al., 2017).
CT Scans in Dentistry
The major deleterious effects of ionising radiations are primarily categorised into two different types namely, stochastic and deterministic effects. The deterministic effects occur when the exposure threshold is exceeded which means deterministic effects, such as skin injuries and cataract formation, takes place when dose exceeds a particular threshold (Roobottom, et. al., 2010). Deterministic effect severity is directly proportional to exposure dose. Some of the most common effects are cataract, sterility, skin erythrema, and radiation sickness.
However, the stochastic effects follow some linear-no-threshold hypothesis that occurs due to ionising effects of symmetrical translocation. Stochastic effects have no radiation dose threshold and therefore are linked with the low radiation doses given during CT. These effects have a long latent period, occur randomly and are dependent on the level and type of radiation given, the tissue undergoing radiation and the age of the person. These lead to cancer, and several hereditary defects such as, Down syndrome. The risk of cancer development is found to follow some linear, that is straight pattern with an increase in radiation dose (Palma et al. 2013).
The effective doses of ionising radiation are used for measuring them in terms of their harm inflicting potential and are measured as Sievert (Sv) units. This unit also takes into consideration the kind of radiation and organ or tissue sensitivity. The stochastic effects of ionising radiation appear several decades later and their likelihood is proportional to the dose of radiation. it Study conducted by Warhekar et.al., reported that 35.6% general private practitioners refer CBCT. Oral radiologists (14.2%) and surgeons (21.9%) are found to be the frequent groups who referred patients for CBCT, followed by prosthodontists and orthodontists (Warhekar et al. 2015). The technique is also referred for the use of conservative dentistry, oral diagnosis, and general dentistry. Further evidence is provided by another study for the fact that periodontists (21%), prosthodontists (14%), and dental professionals with advance education in dentistry (13%) were some of the most requested resident providers, with regards to use of CBCT (Fewins 2017). The mean age of patient referrals was found to be 45 ± 21 years with a predominance of 62% women. Most patient referrals were made from periodontology specialists (17%) and maxillofacial surgeons (51%) (Arnheiter, Scarfe and Farman 2006).
The use of the CBCT technique commonly spans a plethora of clinical procedures and specialties namely, orthopaedics, radiotherapy; dental/maxillofacial, urology, and other interventions (Okano & Sur, 2010). The number of CBCT scans and intervention complexity also control the range of doses (Tsapaki & Rehani, 2007). Radiation protection guidelines involve standard measurement of image quality and doses across different manufacturers (Rawson 2015). Aggregate radiation dose experienced by a population, defined as the product of the number of persons exposed to a source and their average radiation dose. Availability of aggregate dose is recommended (Paul,et. al., 2013) for equipment that are used in CBCT and fluoroscopy. Reduction of dose includes, designing the CBCT equipment meeting the mechanical and electrical safety requirements, containing electronic displays on the operator consoles, and presence of low dose protocols (Rehani et al. 2015). Selections of high dose protocols may be needed in cases that involve visualisation of soft tissues (de Gonzalez et al. 2013). Creating a balance between the exposure and the quality needs help in optimising radiation dose. Reduction of mA (Milliamperage) and kVp (Kilovoltage peak) for the equipment has been found to create no significant loss of the quality of images. Another procedure for radiation protection encompasses bringing about a reduction in the size of X-ray beams to minimum needed size for imaging the object/organ of interest (Rehani et al. 2015). This has been found effective in limiting the dose of harmful radiation exposure to the patients, in addition to improving the quality of images by scatter reduction.
Cone-Beam Computed Tomography (CBCT) Scans in Dentistry
Imaging doses have been found to account for an estimated 2% or more of target doses, with respect to first generation, linac (A linac (linear particle accelerator) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a sequence of oscillating electric potentials along a linear beamline mounted kV CBCT systems (SEDENTEX CT 2011). Thus, radiation protection involves evaluation of the daily CBCT imaging for all patients, for sensitive organs having lower thresholds for non-stochastic effects and paediatric patients having high radiation sensitivity. Use of low-quality neurointervention scan protocols, typically using fewer number of CBCT projections, are usually considered sufficient for producing high-contrast structures such as, bony anatomy or contrast-enhanced vessels. Maintaining sufficient distance from the source of x-rays and use of shields are also effective radiation protection steps (Rehani et al. 2015).
Conventional X-rays use analog film or digital receptor in two-dimensional image of the object. The anatomy in question is in 3 dimensions and radiographs compress these into 2D images. Due to the nature of 2 dimensional images, the diagnostic performance is increasingly limited (Webber et al. 1999, Nance et al. 2000). With this technique, it is difficult to interpret the radiographs that give picture of the surrounding structures while superimposing them. Conventional radiographs do not demonstrate accurately the presence of lesions, its’ real size and spatial relationship with the tooth’s anatomical structures (Cotti et al. 1999), (Cotti & Campisi 2004).
Geometric distortion is a major restraint in accurate diagnosis in endodontics (Gröndahl & Huumonen 2004). The maxillofacial structures are not portrayed accurately in its dimensions. Therefore it is recommended that peri-apical radiographs must be taken using paralleling techniques as opposed to bisecting angle techniques, for the above-mentioned reason (Forsberg & Halse 1994). Even with the most accurate paralleling technique, one can expect a certain degree of magnification (Forsberg & Halse 1994). Over-angulated or under- angulated radiographs may give false measurements of true size of the peri-apical lesion or the accurate root dimensions (White & Pharoh, 2004), (Whaites, 2007).
Multiple anatomical structures lying over each other may obscure the image, leading to superimposition and difficulty in interpretation of these images (Gröndahl & Huumonen 2004). The resolution of conventional radiographs is inferior to CT and CBCT and it is not adequate in performing numerous diagnostic tasks in endodontics (Huumonen & Ørstavik 2002).
These limitations that are overcome by three-dimensional radiographic techniques in endodontic practice (Nemtoi, et.al, 2013).
In the recent years, CBCT has been specifically developed to produce three-dimensional images (3D) that are scattered providing information on maxillofacial skeleton with 3D images of teeth and its surroundings (Nemtoi, et.al., 2013). This method is beneficial as compared to conventional radiography for endodontic diagnosis with numerous advantages described in the subsequent section. Instead of fan-shaped in regular computerized tomography (CT), CBCT gives a more accurate and provide appropriate diagnostic information than histology or biopsy for the evaluation of large periapical lesions (Dance, et. al., 2014). CBCT is particularly created to generate undistorted three-dimensional information of the maxillofacial skeleton as well as three-dimensional images of the teeth and their adjacent tissues (Nemtoi, et.al, 2013).. CBCT utilises a cone-shaped beam rather than the fan-shaped one used by the usual CT scanners (Deepak, et al., 2012). It must also be noted that CBCT may give more accurate diagnostic information than a biopsy and histology, when assessing large periapical lesions (Deepak, et al., 2012).
The Advantages of CBCT Scans in Dental Imaging
CBCT is widely used in endodontics for the evaluation of root canal, study of internal and external macro morphology in 3D, reconstruction of teeth, root canal preparation, , and bone lesions detection and in experimental endodontology that is used for accurate identification of apical periodontitis (Dance, et. al., 2014). This technique can determine the differences in density between granulomatous tissue and cystic cavities making it preferable for non-invasive diagnosis (Durack & Patel 2012). It allows evaluation of each root and the surrounding structures or areas of interest that can be compared over time (Machado, 2015). CBCT has pre-surgical application in locating lesions, proximity to maxillary antrum and mandibular canals (Patel et al. 2013). It has great advantages that include higher resolution, increased accuracy, lower radiation dose and reduction in scan time than conventional radiography techniques. There is also anatomic noise elimination ( the radiograph pattern of a mass of very fine non-distinguishable anatomical structures changes fully from radiograph to radiograph because of the unpreventable movements of the person during the exposure. The corresponding image component shows noise-like behavior and is therefore called as the anatomical noise ( Tischenko et. al., 2005)), facilitation of assessment of important features like diagnosis, treatment and management in endodontics.
CBCT has major advantages over CT scan in terms of substantial reduction in radiation exposure with X-ray beams that are pulsed (Pauwels, et. al., 2015). They are easy to use and require less space, making it suitable for dental practice. The images obtained are displayed in axial, orthogonal, coronal and sagittal planes simultaneously. This display of the tooth allows clinicians to get an accurate anatomical view of the entire tooth and its surrounding tissues providing superior scans for the assessment and management of endodontic problems.
Although, CBCT overcomes various limitations of conventional radiography, the images produced by this technique have some significant problems. It lowers the quality of image in terms of diagnostic accuracy, as the CBCT beam is scattering and hard due to high-density structures in the surrounding like metallic posts, enamel and restorations, diagnostic value lowering of root-canal perforations and internal root resorption (Patel, et al., 2015). When an intracanal metallic post is present while imaging with CBCT, it may result in equivocated readings (unambiguous) due to development of artifact. Artifacts create barriers while analyzing the images when metallic items are present in the subject tooth or in the nearby vicinity (Patel, et al., 2015). In such cases, the CBCT technique is required to be complemented with periapical radiographs to reach a diagnosis (Estrela, et. al., 2008). It is suggested that CBCT should be combined with periapical radiographs for producing accurate pictures of tooth and its surrounding tissues (Patel et al. 2013). In addition, scan times in CBCT are lengthy having 15-20 seconds that requires patients to stay still during the procedure (Gümrü and Tarç?n 2013).
In addition, CBCT is very useful for imaging hard tissues, however for capturing soft tissues it has not been proven very authentic due to absence of a dynamic range (range of receptor exposures over which an image and contrast will be formed) of the x-ray detector (Venkatesh & Elluru, 2017). Further, CBCT poses several medico-legal concerns associated with acquiring and interpreting the data of CBCT (Kapila, Conley, & Harrell, 2011). Certain applications of CBCT such as oral and maxillofacial surgery need a huge (10-15 cm or even more) field of view (FOV) to take each maxillofacial structures into the image (Scarfe, et. al., 2009). Due to these higher radiation doses compared to conventional intra-oral radiography, there is a need for the clinicians using CBCT investigations, to undergo relevant and appropriate training and education, to ensure protection of patients and personal professional development for the clinicians (Jacob et al, 2004; Bordia et al, 2011). It has been noted by oral and maxillofacial radiologists that, dentists who do not have suitable training should not do or interpret the CBCT images (Deepak, et al., 2012).
CBCT has been employed in different fields of dentistry.
Dental Implants: Replacement of missing teeth with dental implants require complete and through assessment of bone and surrounding vital structures (Nagarajan, et. al., 2014). The role of CBCT in implant radiography can be attributed to the fact that the dental cone beam has the property of offering valuable information regarding bone height, width, density and vital structures in the planning and assessment of surgical implants and is now one of the most preferred options of pre-surgical dental implant assessments (Bornstein et al. 2014)
Oral and Maxillofacial Surgery: In oral surgery, includes visualisation of non-erupted and erupted teeth and retained roots that cannot be viewed by 2-d radiography (Pawelzik et. al, 2002). The excellent capability CBCT’s 3D images, of presenting undistorted views of the dentition are accurately used for evaluation of teeth and roots in close relationship with adjacent anatomical structures (Venkatesh & Elluru, 2017). It is also indicated for precise localization of the mandibular canal, mental foramen, and maxillary sinus? to assess its anatomical association to impacted teeth (Pawelzik et. al, 2002). CBCT allows measurement of surfaces distances in planning extensive maxillo-facial surgeries (Cavindanes et. al, 2005; Heiland et. al., 2004)
Orthodontics: CBCT scans for use in cephalometrics has revolutionised orthodontic treatment planning, in assessing facial growth and development of the maxilla and mandible (Harrell, 2007). CBCT can be used for planning location and safe insertion of mini implants in orthodontic patients (Kim et. al. 2007). The availability of software like Dolphin has increasingly eased clinician’s ability to carry out full facial profile measurements for accurate and predictable treatment outcomes (Kapila, et. al. 2007).
CBCT is an extremely beneficial technique in Periodontology to collect exact diagnostic and quantitative information regarding the condition of the bone (Acar & Kamburo?lu, 2014). CBCT has proven to be an effective imaging technique for capturing the mineralized structures like bone (Agrawal, et. al., 2012). CBCT provides an improved detection of bony impairments, craters, and furcation involvements than other available techniques (Pereira & Nagarathna, 2017). For assessing the regenerative periodontal therapy and outcomes of bone grafts accurately CBCT is the choice of imaging technique (Eshraghi, et. al., 2012)
The temporomandibular joint is a region which is difficult to image as the surrounding structures cause superimposition and there are morphological changes alterations (Krishnamoorthy, Mamatha, & Kumar, 2013). The TMJ is examined using numerous radiography techniques, however, since it is a complex region a clear image of the area is required to efficiently diagnose and manage disorders. The technique of CBCT is preferred over other traditional radiographic imaging methods including MRI for assessing osseous TMJ disorders (Larheim, et.al, 2015). CBCT offers a distinct advantage over other methods because of its reduced radiation exposure, smaller equipment and the capacity to give multiplanar reformation and 3D images (Krishnamoorthy, et. al., 2013) .
In Forensic dentistry CBCT has limited use, however it can be used to estimate the age of a person (Sinha, 2018). It is an efficient substitute to tooth extraction, sectioning of teeth and resection of jaw bones (Venkatesh & Elluru, 2017). In addition, it can be utilized for sex determination, frontal sinus pattern and 3D facial reconstruction (Sinha, 2018).
CBCT has specific applications in endodontics including diagnosis of canal morphology, endodontic pathosis, assessment of non-endodontic regions, root trauma and fracture evaluation, internal and external root resorption, pre-surgery planning and invasive cervical resorption (Venkatesh & Elluru, 2017).
Early periapical diseases can be accurately detected using CBCT as compared to conventional X-rays with actual picture of size, nature, extent and position of resorptive and periapical lesions (Ahlowalia et al. 2013). Root canal and fracture anatomy and bone topography surrounding the teeth can also be diagnosed using CBCT (Neves et al. 2014). The scans obtained using this technique are desirable and easy to access the posterior teeth before periapical surgery with accurate determination of thickness of cancellous and cortical bone as the inclination of roots is related to surrounding jaw (Deepak, et. al., 2012). CBCT may also provide a clear picture of anatomical structures such as the inferior dental nerve and maxillary sinus to the root apices (Deepak et. al., 2012).
it has been reported that periapical radiographs are standard radiography techniques for recognition of apical periodontitis (Patel, et al., 2015). It is noted that at the initial stages of AP, the periapical bone lesions is less or superimposed by surrounding structures, so the conventional radiographic images are unable to detect its presence However, CBCT facilitates the detection of periapical bone loss at the early stages when the presence and dimensions of apical lesions and changes in apical bone density occur. Several researchers have highlighted that CBCT has an increased sensitivity when compared to periapical radiography for diagnosing inflammatory changes in the periapical area (Shukla, Chug, & Afrashtehfar, 2017). But, the specificity of both radiography methods is comparable. CBCT can prove to be effective in detecting undiagnosed problems in cases where patients have unlocalized indicators linked with an unmanaged or previously root filled tooth, where clinical and periapical radiographic examination have revealed no evidence of disease (Patel, et al., 2015). It is also helpful in establishing the presence or absence of odontogenic cause of pain while diagnosing the non-odontogenic etiologies of pain (Shukla, Chug, & Afrashtehfar, 2017).
CBCT is applied in endodontic surgery planning. CBCT is efficiently used in pre-surgical assessment for finding lesions, mandibular canals, and the maxillary antrum (Deepak, et al., 2012). This technique facilitates the clear and accurate identification of the anatomical relationship of the root apices with adjacent anatomical structures in different planes (Bornstein, et. al., 2011) . CBCT imaging can assist in carefully planning (or avoiding altogether) periapical surgery of maxillary molar teeth where the sinus floor has been perforated by a bigger than expected periapical lesion, which periapical radiographs failed to detect (Malliet, et. al., 2011) . Axial slices can be utilised to identify previously undetected root canals (Patel, et al., 2015). The exact size of a periapical lesion, its’ location and extent can be understood, while the actual diseased root may be verified (Lofthag-Hansen, et. al., 2007). Therefore, it can be concluded that apart from identifying radiographic indicators of periapical impairments and root canal anatomy, CBCT techniques also ascertain the relationship between the teeth affected with endodontic problems and adjacent anatomical structures accurately (Venkatesh & Elluru, 2017).
For differential diagnosis of dental traumas radiographic examination is necessary (Kullman & Sane, 2012). Various researches have reported that CBCT is appropriate as an additional radiographic tool in cases where the exact characteristics of the dento-alveolar root fracture and dental traumas are not accurately detected through traditional radiographic imaging techniques (May, et. al., 2013).
Intra-oral radiographs are two-dimensional which restricts the accuracy in diagnosing the correct characteristic of horizontal root fractures (Patel, et al., 2015). CBCT can remove these restrictions (Costa, et. al., 2012) . Through conventional intra-oral radiography techniques, there is a considerable amount of risk of misdiagnosis of the location of root fractures in anterior teeth due to the likelihood of an oblique course of the fracture line in the sagittal plane (Patel, et al., 2015). it has been shown that 06CBCT uncovers a substantial amount of information regarding the characteristics of dento-alveolar trauma which helps in diagnosis of the problem and assists in improving management outcomes (Patel, et al., 2015).
Every tooth has different and varied root canal anatomy (Costa,et. al., 2012)). As radiographs are two dimensional by nature, they often fail to reliably identify the exact number of canals present in teeth (Zheng, et al., 2010). This limitation may result in an inability to reveal all the existing roots, which may lead to incomplete disinfection of the root canal system that may eventually cause a failure in the treatment of root canal infection (Anderson, et al., 2012). Therefore, CBCT is an efficient additional technique to the already existing techniques for identifying root canals.
CBCT leads to a more objective view and gives a clue on likely prognosis of root canal treatment (Patel, et al., 2015). As CBCT has poor resolution, calcified and/or accessory anatomical structure may not show up in the images easily. Therefore in the case where root canal anatomy is not completely understood by utilizing the existing radiographic techniques, CBCT can be effectively used. Therfore it is advocated that a use of a dental operating microscope will greatly benefit in aiding location of heavily sclerosed and calcified canals.
The detection of root resorption is difficult as it is chronic, asymptomatic and has a quiescent onset (Hegde & Hegde, 2013). Currently, the standard technique for diagnosing root resorption is periapical radiography. But several in-vitro studies have shown that it is an insufficient technique to detect simulated root resorption, particularly in cases of small cavity size Due to 2D nature of intr-oral perio-apical images, it is difficult to clearly evaluate, both internal and external root resorption cases. Studies have shown that the radiography largely underrates the degree of inflammatory root resorption as compared to CBCT (Patel, et al., 2015). Several in-vitro experiments have demonstrated the superiority of CBCT over periapical radiography for diagnosing simulated root resorption in terms of diagnostic accuracy. In the experiment both intraobserver and interobserver agreements were statistically higher (p < .05) for the Iluma CBCT images than for the intraoral images. Az values for CBCT images were also statistically higher (p < .05) than for film images for all observers and readings. In addition, kappa and Az values of external cervical resorption cavities were statistically higher (p < .05) than those of internal cervical resorption cavities for all observers, image types, and readings. (Kamburoglu, et. al., 2011). So, it can be concluded that evidence suggests the utilization of CBCT as a preferred diagnostic method to evaluate the exact nature of teeth affected with root resorption to develop diagnosis and better management.
A vertical root fracture is defined as a complete or incomplete fracture initiated from the root at any level, usually directed buccolingually. It starts from an internal dentinal crack, and develops over time, due to masticatory forces and occlusal loads. An overall prevalence of 3% to 5% has been reported in retrospective studies (Dhawan, et. al., 2014). However, the percentage of extracted teeth with VRF has been reported to be much higher – 10-20% (Coppens & DeMoor, 2003). Ehanced diagnostic knowledge has led to increased prevalence being reported in recent studies. Higher prevalence is noted in patients of middle and older age (Dhawan, et. al., 2014). The diagnosis of vertical root fractures is especially challenging as the presenting signs and symptoms are not precise especially in cases of incomplete fractures (Ozar, 2010). It has been observed that there is a lack of reliable data pertaining to the validity and efficiency of clinical and radiographic dental assessment for the detection of VRFs in root filled teeth (Tsesis, et. al., 2010)). It has been found that the accuracy of CBCT for diagnosis of simulated VRFs in root filled and non-root filled teeth was considerably more than periapical radiographs (Ozar, 2010). therefore, it can be concluded that CBCT has been found a more accurate technique in diagnosing the presence of VRF (Ozar, 2010).
Teeth show a higher radiographic specificity on outcome of root canal treatment in cases where they are treated before the apparent radiographic signs of endodontic disorders are noticed (Zheng, et al., 2010). Since CBCT can detect periapical radiolucent changes at initial stages, an early diagnosis can be made and improved management of periapical disease can be achieved (Venkatesh & Elluru, 2017). CBCT is an efficient additional technique to the already existing techniques for identifying root canals in cases of missed canals following failed endodontic treatment.
To look at scientific literature or guidelines that will facilitate clinicians in decision making on indications and justification for CBCT scan in endodontic diagnosis and treatment planning.
Study design:
Narrative review
Before we can set out our aims and objectives, it is important to define certain terminologies: These terminologies are used as per definition by IRR99 and IR(ME)R2000 (IRR99 and IR(ME)R2000 regulation)
The Referrer: “A clinician who refers for a CBCT examination, a written report is sent back to the dentist. Referrer may need to review the images, including the report from the reporter/radiologist, for clinical use.”
The Operator: “An person responsible for performing the practical aspects of CBCT examination and undertakes the justification of radiographical exposure.”
The Referrer-Reporter: “A dentist who refers for a CBCT examination to the operator, and is responsible for reporting these images himself/herself.”
The Aim of the study is
- To look at scientific literature or guidelinesthat will facilitate clinicians in decision making on indications and justification for CBCT scan in endodontic diagnosis and treatment planning.
The objectives of the study are
- To determine if the published guidelines are clear and consistent (based on literature) that facilitates them to justify CBCT scans for endodontic diagnosis and treatment planning.
- To determine if the guidelines set out in the European Society of Endodontology position statement and American Association of Endodontists (AAE) and American Association of Oral and maxillofacial Radiologists (AAOMR) joint position statement are up to date, clear and consistent in order for clinicians, (the referrers, the practitioners and the referrer-reporters) to have guidelines that they can follow and rely upon in use of CBCT scans in endodontic diagnosis and treatment planning.
References:
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