9 Radiographic Interpretation of Traumatic Injuries

9

Radiographic Interpretation of Traumatic Injuries

Nestor Cohenca

Introduction

The world of endodontics has witnessed several changes in the past decade. New technologies, instruments, and materials have resulted in better diagnosis and more predictable therapy. The application of computer based-systems and the development of electronic sensors have provided the technical means to apply theoretical principles to diagnostic imaging. Among these innovations, digital radiographic imaging has introduced a new dimension with many potential benefits for endodontic practice and has significantly improved the ability to accurately diagnose in a cost- and dose-efficient manner (Berkhout et al., 2004). Recent improvements in three-dimensional (3D) digital radiographic imaging introduced a new perspective, allowing us to evaluate the anatomic structures, both hard and soft tissue, in three spatial planes (Scarfe, 2005). Comparing with the traditional projection (plain film) radiograph, which is a two-dimensional shadow of a 3D object, 3D imaging overcomes this major limitation by providing a true representation of the anat­omy while eliminating superimpositions. Several studies have reported the use of computerized tomography and digital radiography for differential diagnosis (Shrout et al., 1993; Simon et al., 2006; Trope et al., 1989), assessment of treatment outcomes (Camps et al., 2004; Cotti et al., 1999), endodontics (Cotton et al., 2007), oral and maxillofacial surgery (Danforth et al., 2003a; Eggers et al., 2005; Ziegler et al., 2002), implantology (Hatcher et al., 2003; Sato et al., 2004), and orthodontics with reliable linear measurements for reconstruction and imaging of dental and maxillofacial structures (Baumrind et al., 2003; Danforth et al., 2003b; Maki et al., 2003).

The incidence of dental trauma due to falls, sports, automobile accidents, and violence has increased significantly in recent decades, affecting children’s and teenagers’ anterior teeth (Andreasen and Andreasen, 1994). In combination with clinical tests and observations such as percussion, palpation, tooth mobility, coronal color changes, pulp sensitivity, and vitality, the first clinical and radiographic examination of the traumatized patient is critical. The information gathered allows the clinician to determine the initial diagnosis, severity of the injury, develop a treatment plan, and create a baseline for follow-up. When correctly performed and adequately interpreted, these tests are reliable in diagnosing pulp necrosis (Andreasen, 1988a).

Following a traumatic injury, we must differentiate between the first radiographic examination of the patient, immediately after the injury, and the follow-up examinations. During the first radiographic examination, our focus should be on diagnosing bone fractures of the mandibular and maxillary processes, alveolar bone fracture(s), root fracture(s), displacement of teeth, and stage of root development/maturation. Follow-up radiographic examination is aimed at diagnosing widening of the periodontal ligament (PDL), disturbance of lamina dura, periapical radiolucencies, root resorptions, repair of root fractures, pulp canal obliteration, and root maturation/development.

Stage of Root Development

In 1960, Nolla published classification for odontogenic development using radiographic interpretation (Table 9.1) (Nolla, 1960). This classification has been widely used by all specialties throughout the years including current articles (Oliveira et al., 2008; Pioto et al., 2005).

Table 9.1 Radiographic classification for odontogenic development.

0 No crypt
1 Presence of crypt
2 Initial calcification
3 One-third crown completed
4 Two-thirds crown completed
5 Crown almost completed
6 Crown completed
7 One-third root completed
8 Two-thirds root completed
9 Root almost open (open apex)
10 Root apex completed

Knowledge of the developmental stages of permanent teeth is essential for clinical practice in several dental specialties, since it may influence diagnosis, treatment planning, and outcomes. This is particularly true in cases of immature and traumatized teeth. In 1976, Fulling and Andreasen demonstrated that the late differentiation of Ad nerve fibers in the dental pulp could explain the lack of a reliable and predictable response of erupting and undeveloped teeth to thermal and electrical stimulation (Fulling and Andreasen, 1976). In young patients with immature teeth, carbon dioxide (CO2) snow and dichlorodifluoromethane are the most reliable sensitivity tests followed by the electric pulp test and ethyl chloride and ice (Fuss et al., 1986). Therefore, in absence of reliable clinical tests, radiographic evidence of root development and dentin maturation during follow-up examination may be critical in providing the clinician with reliable information related to the presence of a vital dental pulp.

Traumatic Injuries

Radiographic interpretations of traumatic injuries will be thoroughly described and illustrated using the classification proposed by Andreasen and Andreasen in 1994 (Glendor et al., 2007) and adopted by the World Health Organization (WHO). Feliciano and Franca Caldas evaluated 164 articles and 54 different classifications and they concluded that, according to the literature, the most frequently used classification system was that of Andreasen (32%) (Feliciano and de Franca Caldas, 2006). Treatment recommendations are based on the official guidelines of the International Association of Dental Traumatology (IADT) (Flores et al., 2007a, 2007b, 2007c).

Injuries to the Hard Dental Tissues and the Pulp

1. Enamel fracture

a. Definition: A fracture confined to the enamel with loss of tooth structure.
b. Clinical features: Crown fracture involving enamel only with no visible sign of exposed dentin (Figure 9.1).
c. Radiographic features: The enamel loss is visible.
d. Recommended radiographs: Periapical radiographs at different horizontal angles (Brynolf, 1970a, 1970b; Wilson, 1995). This recommendation is aimed at ruling out the possible presence of a root fracture or a luxation injury (Bender and Freedland, 1983a). In case of lip laceration or swelling, a radiograph of the lip is indicated to search for tooth fragments or foreign material (Figure 9.2).
e. Recommended treatment: The main purpose is to restore esthetics. Etch-bond resin restorations are the treatment of choice.

Figure 9.1 Clinical and radiographic diagnosis of enamel fracture of the maxillary left central incisor.

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Figure 9.2 Lip laceration and swelling. A radiograph of the lip demonstrated the presence of tooth fragments within soft tissues.

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2. Uncomplicated enamel and dentin fracture

a. Definition: A fracture confined to enamel and dentin with loss of tooth structure, but without pulpal exposure.
b. Clinical features: Crown fracture involving enamel and dentin with no visible exposure of the pulp (Figure 9.3a).
c. Radiographic features: A visible fracture is observed involving the loss of enamel and dentin, with no evidence of pulpal involvement.
d. Recommended radiographs: Periapical radiographs at different horizontal angles. This recommendation is aimed at ruling out the possible presence of a root fracture or a luxation injury. In case of lip laceration or swelling, a radiograph of the lip is indicated to search for tooth fragments or foreign material. Evaluate size of the pulp chamber and determine the stage of root development.
e. Recommended treatment: Clinical tests and radiographic examination. The exposed dentin should be protected by placing glass ionomer liner over the exposed dentin. A bonding agent and composite restoration is then indicated to restore the esthetics and function (Figure 9.3b). If an intact fragment exists, a bonding procedure may be carried out (Yilmaz et al., 2010). Check the occlusion.
f. Patient instructions: Soft diet and good oral hygiene.
g. Urgency: Subacute (within 24 hours) or delayed (more than 1 day).
h. Follow-up. Clinical and radiographic examination at 6–8 weeks and 1 year.

Figure 9.3 Uncomplicated crown fracture of the maxillary right central incisor. (a) Preoperative and (b) postoperative restoration with composite resins.

Courtesy of Dr. Gabriela Ibarra.

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3. Complicated enamel and dentin fracture

a. Definition: A fracture confined to enamel and dentin with loss of tooth structure and pulpal exposure.
b. Clinical features: Crown fracture involving enamel and dentin with a visible exposure of the pulp (Figure 9.4a).
c. Radiographic features: A visible fracture is observed involving the loss of enamel and dentin reaching the pulp chamber (Figure 9.5).
d. Recommended radiographs: Periapical radiographs at different horizontal angles. In case of lip laceration or swelling, a radiograph of the lip is indicated to search for tooth fragments or foreign material. For moderate to severe trauma, Cohenca et al. recommended the use of cone beam computed tomography (CBCT) for accurate diagnosis and treatment planning (Cohenca et al., 2007). Periapical radiographs indicated the presence of complicated fractures on the right maxillary lateral incisor and both maxillary central incisors (Figure 9.5). However, further evaluation of the case using CBCT illustrated a clear crown–root facture on the lingual aspect of the right maxillary lateral incisor (Figure 9.6). Evaluate size of pulp chamber and determine the stage of root development.
e. Recommended treatment: Clinical tests and radiographic examination. Pulp capp­ing, partial pulpotomy, cervical pulpotomy, or pulpectomy are all alternative treatment options. Cvek et al. (Cvek, 1978) recommended partial pulpotomy using pure calcium hydroxide. A dentinal barrier was radiographically evident at 3–6 months in 96% of the cases. Fuks et al. obtained similar results with no correlation between healing and size of pulp exposure, type of trauma, time frame, and root development (Fuks et al., 1987). Current literature recommends the use of mineral trioxide aggregate (MTA) as the material of choice instead of calcium hydroxide (Karabucak et al., 2005). The rational for this recommendation relies on the sealing ability and biocompatibility of MTA. Figure 9.6 illustrates the treatment of a complicated crown fracture with partial pulpotomy and MTA (Figure 9.7). Upon completion of the pulpal treatment, a composite-based restoration is indicated to restore the esthetics and function (Figure 9.4b). Check the occlusion.

i. Patient instructions: Soft diet and good oral hygiene.
ii. Urgency: Subacute (within 24 hours).
iii. Follow-up. Clinical and radiographic examination at 6–8 weeks and 1 year.

Figure 9.4 Complicated crown fracture of the maxillary left central incisor. (a) Preoperative and (b) postoperative restoration with composite resins.

Courtesy of Dr. Gabriela Ibarra.

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Figure 9.5 Complicated crown fracture of the maxillary right central and lateral incisors and maxillary left central incisor. (a–b) Periapical radiographs at different horizontal angles.

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Figure 9.6 Complicated crown fracture of the maxillary right central and lateral incisors and maxillary left central incisor (same case of Figure 9.5). Cone beam computed tomography demonstrating an additional crown–root fracture on the maxillary right lateral incisors that was not visible on the periapical radiographs.

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Figure 9.7 Complicated crown fracture of the maxillary right central incisor. Partial pulpotomy procedure clinically illustrated by steps: (a) Pulp exposure, (b) pulpal tissue excised 2 mm below the exposure, (c) bleeding control by pressure only (cotton pellet moisted on saline), (d) hemostasis obtained, (e) white MTA seal, and (f) protection of the MTA using a layer of glass ionomer lining.

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4. Crown and root fracture

a. Definition: Fracture involves enamel, dentin, and root structure.
b. Clinical features: Crown fracture involving enamel and dentin extending into the root structure (Figure 9.8). The pulp may or may not be exposed. Additional findings may include loose, but still attached, segments of the tooth. Sensibility testing is usually positive.
c. Radiographic features: Apical extension of fracture may be visible on a regular periapical radiograph (Figures 9.9 and 9.10).
d. Recommended radiographs: Periapical and occlusal exposures. A cone beam exposure might be necessary to reveal the extent of the fracture.
e. Recommended treatment: Treatment considerations are similar to the ones described for complicated crown fractures. As an emergency treatment, stabilization of the coronal fragment with acid etch/resin splint to the remaining tooth structure and adjacent teeth is recommended (Figure 9.11). If the fracture is subgingival, expose the fracture site by gingivectomy or orthodontic/surgical extrusion. If root formation is completed, endodontic therapy is indicated. Otherwise, if the root is immature, partial or cervical pulpotomy is indicated.
f. Patient instructions: Soft diet and good oral hygiene.
g. Urgency: Subacute (within 24 hours).
h. Follow-up. Clinical and radiographic exam­ination at 6–8 weeks and 1 year.

Figure 9.8 Crown–root fracture of the maxillary left central incisor. (a) Clinical view of the fracture immediately after injury, (b) periapical radiograph demonstrating the complicated crown–root fracture, (c) clinical gingivectomy exposing all the fracture’s fragments, and (d) remaining tooth structure after removal of the fracture fragments.

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Figure 9.9 Crown–root fracture of the maxillary left central incisor. (a–c) Periapical radiographs at different horizontal angles.

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Figure 9.10 Crown–root fracture of the maxillary left central incisor (same case of Figure 9.9). Periapical radiographs. (a) Immediately postoperative, (b) 2 months follow-up, and (c) 6 months follow-up.

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Figure 9.11 Crown–root fracture of the maxillary left central incisor. (a–d) Emergency procedure for stabilization of the coronal fragment with acid etch/resin splint to the remaining tooth structure and adjacent teeth.

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5. Root fracture

a. Definition: A fracture confined to the root of the tooth involving cementum, dentin, and the pulp. Root fractures can be further classified by level in coronal, middle-root, and apical. It can also be classified based on the direction in vertical, horizontal, and oblique planes. Most root fractures related to traumatic injuries are horizontal and are at the middle-root level. The coronal fragment of the tooth is often displaced. Apical segment is usually not displaced.
b. Clinical features: The coronal segment may be mobile and in some cases displaced. Transient crown discoloration might be present.
c. Radiographic features: The root fracture line is usually visible on a periapical radiograph. The fracture involves the root of the tooth and is more often horizontal (Figure 9.12).
d. Recommended radiographs: A multidirectional approach using a conventional periapical exposure and two additional vertical periapical projections that vary ±15–20 degrees from the central beam has been advocated by several authors (Andreasen et al., 2007; Bender and Freedland, 1983a, 1983b; Degering, 1970; Wilson, 1995). A cone beam exposure might be necessary to reveal the extent and direction of the fracture (Figure 9.13a–c) (Cohenca et al., 2007). Recently, Bornstein et al. compared intraoral occlusal and periapical radiographs versus limited CBCT in diagnosing root-fractured permanent teeth and concluded that the diagnosis of the location and angulation of root fractures based on limited CBCT imaging differs significantly from diagnostic procedures bas/>

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Jan 12, 2015 | Posted by in Oral and Maxillofacial Radiology | Comments Off on 9 Radiographic Interpretation of Traumatic Injuries
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