Endo Tribune Asia Pacific Edition

Trends & Applications ENDOTRIBUNE Asia Pacific Edition No. 3/201518 disputed, the American Associa- tion of Endodontists and the American Academy of Oral and Maxillofacial Radiology jointly published a statement in 2011 in which they stated that limited volume should be preferred over large volume and that this imag- ing technique should not be used routinely for endodontic diag- nosis or for screening purposes. Furthermore, the clinician must justifythattheuseofCBCTwillbe of benefit to the patient and that its use outweighs the potential risks.3 Intra-oral radiographs, such as conventional and digital peri- apical radiographs, are still rou- tinely used as one of the impor- tant investigative tools during endodontic examination and the diagnosis stage. Even though it has a few limitations, an appro- priatelytakenandprocessedperi- apical radiograph can still pro- vide enough information and evidence to aid in diagnosis. An acceptable periapical radiograph must have adequate contrast and no or minimal processing error and include at least 3 mm of the surrounding periapical area to allow accurate assessment of the tooth of interest and its surround- ing area. Additional periapical radiographs at different angula- tions (10–30 degrees horizontally or vertically) could be taken to determine the location of a peri- radicular lesion or any resorptive defect present on the root and its surface (internal or external).4–6 An earlier study has shown that accuracy in detecting the pres- ence of twin canals increased usingaperiapicalradiographwith a horizontal shift.4 Another con- cluded that the detection of peri- apical lesions was more accurate with an angulated radiograph.6 However, the degree of angula- tion should not be excessive, as it would result in overlapping of the image or changes in the image size, thus reducing the diagnostic quality of such a radiograph.7 Periapical radiographs taken at different angulations may be necessary in order to determine thenumberofrootandrootcanals of a tooth, especially in premolars and molars. Several studies have shownthatradiographstakenata horizontalangleof30degreesim- provestheabilitytodeterminethe canal type in premolar teeth.9, 6, 4 Periapical radiographs can be takeneitherbyusingtheparallel- ing or bisecting angle technique. Dentalradiographsareneeded for the assessment of the crown, pulp chamber, root(s) and peri- radicular area of a particular tooth (Table 3). Clinicians should make it a routine to assess the entire radiographthoroughly(i.e.thead- jacent teeth and its surrounding tissue)beforefocusingonthetooth of interest. It is essential to ensure that the radiograph is mounted correctlypriortoassessment.This is to prevent misdiagnosis or mis- interpretation of the radiograph. Use of magnification, such as a magnifying glass, could aid in detailed assessment of the radio- graph. Restoration status and the presence of a carious lesion or periapical pathology on any tooth should be identified, documented andincludedinthetreatmentplan. When assessing the radiograph of the tooth of interest, the clinician should start from the crown then movetowardstherootanditsperi- radicular area. Any findings must be included in the documentation and considered when deciding on the treatment option. The periapical radiograph musthaveminimaldistortionand magnification, as any elongation or foreshortening would result in incorrect measurement of the root canal length. Careful assess- ment of the root is essential to identify any root aberration that may be present (Fig. 1). It is quite common to find a Chinese patient with a C-shaped canal or other Mongoloid trait with an aberrant root or root canal anatomy.10 Thus, thorough assessment of the radiograph is necessary to as- certain the presence of additional roots or root canals and thereby establish treatment difficulty. Since endodontic therapy in- volves the treatment of the root canal, which is not visible to the naked eye, radiographs aid in determining whether treatment was carried out satisfactorily and adequately. Preoperative assessment Dental radiographs are im- portant in endodontic therapy to determine tooth morphology, as- certain the cause of the dental problem and provide an early as- sessment of the tooth of interest. Based on a radiograph, the re- storability of a tooth and the com- plexity of the treatment can be assessed. It also helps clinicians decide whether he or she has the skills to perform the treatment or should refer the patient to a specialist. The presence of a pulp stone in the pulp chamber or another ob- struction within the tooth or root canal (e.g. a post, a pin, a sepa- rated instrument or root filling material) can be determined prior to treatment (Fig. 2). This is AD 1 Fig. 1: Presence of birooted mandibular premolar.—Fig. 2: Separated instrument in lower incisor.—Fig. 3: Inadequate root canal filling on lower left molar.—Fig. 4: Measuring the depth of pulp chamber during cavity access preparation. page 17ET Area Factors assessed Rationale Crown •Caries (depth, location, extension) •Restoration status (secondary caries, margins, depth, extension) Assessment of the restorability of the tooth and treatment complexity. Pulp chamber •Size, shape, location of the pulp horn •Distance to the occlusal surface of the crown Ensures the depth and direction of the bur during access Prevents iatrogenic perforation of the tooth during access preparation. Root •Number of roots •Size of roots •Curvature (degree, direction) •Presence of accessory roots •Crown–root ratio Determination of the number of roots and root canals is important to avoid missed and untreated canals, which would result in endodontic treatment failure. The presence of excessive root curvature would indicate the level of difficulty of the treatment. Root canal •Number of root canals •Size of canals •Presence of accessory/ lateral root canals The clinician must pay extra attention when treating sclerosed or obliterated canals. Use of magnification, such as dental loupes or a microscope, is recommended in this situation. Table 3: Factors to consider during radiograph assessment. 2 3 4 234

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