Quality Resource Guide l Diagnosing and Managing the Cracked Tooth Part One 3rd Edition 4 www.metdental.com COF can mimic many other conditions, such as teeth with caries, it is prudent to maintain a high degree of suspicion when a general dental examination yields symptoms and examination findings that are contradictory. Diagnosis A tentative diagnosis of COF can sometimes be made based on symptoms. Absent caries, a tooth that is painful to chewing (particularly fibrous food) may be considered to possibly have a COF. But since symptoms can be very diverse and clinical findings difficult to obtain, the clinician must systematically collect available information before finalizing a diagnosis. A study of 95 patients presenting with longitudinal fractures in teeth were evaluated with periapical radiographs and CBCT. CBCT showed 4.4 times greater odds to detect bony defects suggestive of fractures versus periapical radiographs. Teeth with vertical root fractures (VRF) were more associated with absent bony cortical plates, showed J-shaped radiolucencies and deeper probings (>6 mm), and were associated with indirect restorations. Cracked teeth (COF) were associated with direct restorations, shallower probings (<6 mm), and the cortical plates were intact. The CBCTs showed angular bony defects. 13 Radiographic Information is often of relatively minor value in identifying a COF. Since the vast majority of fractures run in a mesial-distal direction, a typical radiographic image will not show a break in tooth continuity. However, in a small number of facial-lingual positioned fractures, the radiographic image can show the fracture since the x-ray beam runs parallel to the fracture (Figure 9). Cone beam computed tomography (CBCT) has made radiographic examination of dental conditions more easily visualized than ever before. Teeth with vertical root fractures (VRF) can be recognized on CBCT images, 14 But this technology is less applicable for the diagnosis of teeth with a COF. Clinical Findings can provide many clues. Direct observation of an intact tooth with no restorations may allow identification of fracture lines. If a possible fracture is noted on one or both of the marginal ridges, confirmation of a COF can be obtained by transillumination. 15 Fracture lines in dentin will block transilluminated light and the tooth structure opposite the fracture line will be dark (Figure 10). 15 An enamel craze line may be highlighted with transillumination, but it will not prevent the light from continuing through the crown (Figure 7). Fracture lines may also be highlighted with the use of red dye (Figure 4) or methylene blue. If restorations are present, they may need to be removed for direct observation of potential COF. Since localization of the affected tooth can be difficult, it may sometimes be necessary to remove restorations from several teeth before identifying the correct one. Brynjulfsen et al. 4 recommended methodically removing restorations, one tooth at a time, to locate teeth with COF in patients with long standing, undiagnosed orofacial pain. An important step in the clinical examinations is conducting a biting test. 16 Various techniques have been recommended, such as biting on Burlew Wheels, rubber wheels, cotton tip applicators, moist cotton rolls, and commercial biting applicators. To differentiate between biting pain from restorations and microleakage/pain from COF, a biting applicator can be placed separately on either the restoration or the cusps. The result may suggest a leaky restoration or a COF. Another clue to the possibility of COF is the response to biting. A significant pain response to biting, experienced on release of biting pressure, is referred to as either “rebound pain” or “relief pain”. 16 Kahler et al. 11 explained that the pain associated with release of pressure results from fluid movement as the crack rapidly closes. This can be used diagnostically by having the patient bite on a moist cotton roll. If “rebound” pain occurs on release, there is a higher likelihood that one of the two opposing teeth has a COF (Figure 11). Figure 9 Facial-lingual COF (arrow) is visible radio- graphically because the x-ray beams run parallel to the fracture line. Figure 10 Transillumination highlights a fracture (arrow) that involves the enamel and dentin. Figure 11 Clinical test for COF using a moist cotton roll placed between a maxillary and mandibular tooth - a “positive” test is “rebound” pain coming from one of the teeth.