of Endodontics in Dental Trauma

Fig. 4.1

a, b Pre-operative images of lateral luxation on tooth #8 and uncomplicated crown fracture on tooth #9. Soft-ware imaging from Kodak depicting the CBCT axial c, sagital d, and coronal e orthogonal planes of tooth #8, which aided in gathering more diagnostic information for ideal treatment planning. (Courtesy of Kristine Knoll, DDS, MS)

If lacerations are present and sections of the traumatized tooth are missing, it is advisable to take a soft tissue radiograph of the lacerated area prior to suturing to ensure there is no foreign body present in the soft tissue. To perform this, place a normal digital sensor over the lacerated area and use a reduced kilovoltage to expose the area. Cone beam computed tomography has also been shown to be useful in identifying fragments located in the soft tissue [6]. These techniques should allow the clinician to visualize the presence or absence of multiple foreign bodies, including missing tooth fragments (◘ Fig. 4.2).

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig2_HTML.png
Fig. 4.2

a Intra-oral photograph of lateral luxation with crown infraction on tooth #8, subluxation with uncomplicated crown fracture on tooth #9, cutaneous lacerations in philtrum region, and vermillion lacerations on mandibular lip. Occlusal films of mandibular anterior b, c teeth taken to rule out presence of foreign body. (Courtesy of Kristine Knoll, DDS, MS)

4.2.3 Clinical Examination

The reader is directed to ► Chap. 3 for a full description of the clinical examination following trauma, but some discussion on the changes in the pulpal and periapical responses to testing is warranted to further the understanding of the results.

It should be remembered that vitality testing is not a test of the vitality of the tooth; rather it is a response to a stimulus and does not indicate the presence or absence of a blood supply. As such, teeth that initially respond positively may not retain their vitality with time, and conversely, teeth that respond with a negative test may not be necrotic. It may take up to 9 months for the blood supply to return to normal in a traumatized tooth, and the importance of follow-up cannot be stressed enough [7]. Laser Doppler flowmetry and pulse oximetry have both been shown to aid in the diagnosis of the pulpal vitality rather than sensitivity [8]; however the disadvantages include the cost of these instruments and reproducibility, as the absorbed light may be affected by restorations or height of the pulp horns (◘ Fig. 4.3).

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig3_HTML.png
Fig. 4.3

a Nellcor OxiMax N-65 pulse oximeter; after removal of the sedation external finger cover, the individual sensors can be placed on the tooth in question. b White sensor transmits both infrared and red light wavelengths, which is absorbed by the tissue and the amount depends on the ratio of oxygenated and deoxygenated hemoglobin in the blood. The black sensor detects the absorbed light, which can also be affected by restorations or pulp horn heights (Nellcor Puritan Bennett, Boulder, CO; now part of Covidien). (Courtesy of Scott B. McClanahan, DDS, MS and the Endodontic Department at the University of Minnesota)

4.3 Clinical Management of Traumatic Injuries

Following a definitive diagnosis, it is important to provide the correct treatment to allow the patient to return to function on the tooth for an extended period of time.

4.3.1 Crown Fractures Classification and Pulpal Treatment

The majority of crown fractures occur in caries-free healthy teeth [9, 10]. As such, maintaining the pulp vitality is essential.

4.3.1.1 Crown Infraction

Crown infractions are incomplete fractures involving the enamel, without loss of any tooth structure [1]. The risk for pulpal necrosis is low following these types of injuries.

4.3.1.2 Uncomplicated Crown Fractures

Uncomplicated crown fractures are when the fracture involves either the enamel or dentin but does not involve the pulp. The patient will usually present with sensitivity to cold but otherwise normal pulp vitality testing. Soft tissue radiographs should be taken in order to locate any missing fragments if lacerations are present [4]. If the fragment is available, bonding it to the tooth has a good long-term success rate with an acceptable esthetic result [11]. In cases where the tooth fragment is not available, conventional restorative dentistry using bonded composite or ceramic crowns should act as the definitive treatment. If the dentinal fracture is close to the pulp (within 0.5 mm), a base with hard-set calcium hydroxide is recommended to decrease the reactive inflammation associated with bonding agents [1214]. More recent studies have also recommended the use of mineral trioxide aggregate (MTA) [15, 16] or other bioceramic materials, Biodentine, along with a resin modified glass ionomer (RMGI) [17], as indirect pulp capping materials.

4.3.1.3 Complicated Crown Fractures

A complicated crown fracture is when the fracture involves the enamel, dentin, and pulp. The most important factor in the treatment of this injury is the time since the trauma. If left untreated, these teeth will always progress to pulpal necrosis due to the presence of bacteria in the oral cavity [18]. Bacteria are not expected to travel more than 2 mm apically within the first 48 h after a pulpal exposure [19], which gives the clinician many different treatment options to maintain pulp vitality, depending on the level of development of the root and the size of the exposure. In cases where the root has not completed development, the goal is to maintain pulpal vitality to ensure continued root formation and increased thickening of the dentinal walls, which reduce the chance of fracture, in a process called apexogenesis [20]. These procedures include pulp capping, indirect or direct, and pulpotomies. The severity of removing the pulp in a mature root is much less than that of an immature tooth due to the high success rates of pulpectomy [21] and traditional root canal therapy [22]. However, vital pulp therapy has been shown to be a successful procedure in mature teeth [23], especially in younger patients [24].

Vital Pulp Therapies Used in Dental Trauma

  1. 1.

    Indirect pulp cap

     
  2. 2.

    Direct pulp cap

     
  3. 3.

    Cvek type pulpotomy

     
  4. 4.

    Apexogenesis

     
Once the pulp has been addressed, the tooth is restored in the same manner as the uncomplicated crown fracture (◘ Fig. 4.4).

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig4_HTML.png
Fig. 4.4

Pre-operative image b of tooth #9, with history of complicated crown fracture a and previously initated therapy. Endodontic therapy was treated in multiple visits c. (Courtesy of Chris Saylor, DDS, MS)

4.3.1.4 Pulp Capping (Vital Pulp Therapy)

When a vital and asymptomatic pulp becomes exposed to the external environment, the least invasive procedure is the placement of a pulp capping material directly onto the surface of the exposed pulp. The procedure is as follows:

After anesthesia and placement of a dental dam, the exposed pulp tissue should be gently rinsed with diluted (1.5%) sodium hypochlorite (NaOCl). A sterile cotton pellet soaked in NaOCl is then placed over the exposure for 5 min. Bleeding should be assessed at this point, if it is controlled by a moist cotton pellet, placement of a capping material can then occur. If the bleeding is still significant, a pulpotomy is recommended. Acceptable pulp capping materials are MTA or other bioceramic materials. Calcium hydroxide was historically used as a capping material but has been shown to have a higher failure rate. As such, its use should be curtailed in favor of more modern materials [23]. Both the original gray MTA and white MTA have been associated with staining, so in cases where there is an esthetic concern, newer bioceramic materials such as Biodentine should be utilized [25]. A final restoration is then placed over the bioceramic.

When performed under a sterile field using a rubber dam and modern bioceramic materials, direct pulp caps have a very high success rate [23]. Factors that decrease the long-term success include amount of time the tooth has been exposed to the oral environment, use of non-biocompatible materials as a pulp capping material (calcium hydroxide, glass ionomer, composites), nonmechanical pulpal exposures, and lack of an adequate coronal seal [26].

4.3.1.5 Cvek Pulpotomy (Vital Pulp Therapy)

A pulpotomy is the surgical removal of the coronal portion of vital pulp tissue that is then covered by a biocompatible material and restoration. A variation of this procedure is called a Cvek pulpotomy, which is used specifically for traumatically exposed pulps. In this procedure, a smaller portion of the inflamed pulp tissue is removed compared to the full pulpotomy. The long-term success of this procedure is high and should be the first procedure attempted in fracture cases with higher levels of inflammation [27].

In this procedure, the patient is anesthetized, and a dental dam is placed. The exposed pulp tissue is then removed using a sterile bur or endodontic spoon to the level of the cementoenamel junction (CEJ). The tissue is then gently irrigated with diluted 1.5% NaOCl, and a cotton pellet soaked in NaOCl is placed over the exposed site for 5 min. A bioceramic material is placed over the remaining pulp. The aforementioned esthetic concerns should be taken into account. A final restoration is then placed over the pulp capping material.

4.3.1.6 Apexogenesis (Vital Pulp Therapy)

Apexogenesis is a form of a regenerative procedure where the goal is the preservation of vital radicular pulp tissue to encourage continued root development with apical closure [28]. This procedure is performed on teeth with vital (or inflamed) pulps with open apices.

After anesthesia and rubber dam isolation, the tooth is accessed, and the majority of the coronal pulp tissue is removed to the level of the canal orifices using a high-speed diamond bur with water-cooling. [29]. The chamber should be rinsed with sterile saline or water to remove debris, and then the chamber is dried using cotton pellets. Once the bleeding is controlled, calcium hydroxide or MTA is placed over the canals, and a long-term coronal restoration is placed. Follow-up should occur every 3 months to ensure successful root formation and no signs of pulp necrosis, resorption, or periapical pathosis.

Once the roots have finished development, the operator can then continue monitoring the tooth or can elect to perform conventional root canal therapy. Although there is some controversy over which approach is superior, the inability to determine pulp vitality and the ability to initiate the endodontic therapy prior to the development of root resorption, canal obliteration, or the development of apical periodontitis should result in a higher long-term success rate [21, 30].

4.3.1.7 Crown-Root Fractures

A crown-root fracture is when the fracture involves the enamel, cementum, dentin, and sometimes the pulp. The apical location of the fracture should be confirmed using multiple periapical radiographs or CBCT imaging and influences the prognosis of the tooth. Emergency treatment includes stabilization of the fractured segment and either placement of a pulp cap (◘ Fig. 4.5), pulpotomy, or root canal therapy depending on the stage of development and size of the exposure. Final treatment will depend on the location of the fracture and can include surgical or orthodontic extrusion, gingivectomy with crown lengthening, decoronation, or extraction [4] (◘ Fig. 4.6) (see ► Chap. 3 for details of decoronation treatment).

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig5_HTML.png
Fig. 4.5

Pre-operative image a of tooth #9, with history of complicated crown-root fracture and mobility of coronal segment b, c. Endodontic therapy was recommended, as well as possible crown lengthening after prosthodontics consultation. (Courtesy of Kristine Knoll, DDS, MS)

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig6_HTML.png
Fig. 4.6

Pre-operative image a of tooth #9, with complicated crown-root fracture (white arrow). Endodontic therapy was completed in multiple visits b, and pt is asymptomatic at 6 month recall show c. (Courtesy of Chris Saylor, DDS, MS)

4.3.1.8 Root Fractures

A root fracture involves the fracture of cementum, dentin, and pulp and is most commonly seen in mature teeth with closed apices [31]. In certain cases, the coronal fragment will be displaced coronally and will be mobile. This displacement disrupts the pulpal blood circulation and causes pulpal necrosis in the displaced fragment in approximately 25% of cases [32, 33]. The apical fragment is rarely affected. Multiple radiographs are necessary to visualize the fracture line on traditional periapical films. Occlusal films and CBCT imaging are also useful to localize the fracture site.

Treatment for root fractures begins by repositioning the fragments as close as possible to their original position using radiographic imaging. Once the fragments are repositioned, a flexible splint should be placed for 4 weeks [34]. In cases where the fracture is located in the coronal region of the root, the splint can be left for up to 4 months [4].

There are four different responses to root fractures that have been described in the literature: healing with hard tissue, healing with connective tissue, healing with the bone and connective tissue, and interposition of granulation tissue [35, 36]. The proximity of the two fragments influences what type of material is formed between the apical and coronal sections [37]. The first three are considered successful outcomes and should be monitored closely to ensure proper healing is achieved. Coronal pulp obliteration is possible and can result in yellowing of the tooth [38]. In cases where the coronal fragment becomes infected, the bacterial by-products cause an inflammatory response which forms a radiolucency at the fracture line [35]. If the fragment is stable, root canal therapy on the coronal fragment alone should be sufficient. The size of the canal at the apical extent of the coronal segment is often quite large, and thus apexification with long-term calcium hydroxide treatment or placement of an MTA is indicated. In cases where both segments have become infected, surgical removal of the apical portion is suggested in addition to the aforementioned treatment of the coronal segment.

4.3.2 Luxation Injuries

Luxations occur when the tooth is traumatized and sometimes moved from its normal location in the socket. These include the following types of injuries : concussion, subluxation, extrusive luxation, lateral luxation, avulsion, and intrusive luxation. The reader is directed to ► Chap. 3 for specific definitions of the different types of luxation injuries.

4.3.2.1 Concussions and Subluxations

Teeth that have concussion or subluxation injuries generally do not require any treatment beyond vitality testing and monitoring. It should be noted that these teeth can have irregular responses to vitality testing, and the responses should be noted and compared to testing at later dates [39, 40].

4.3.2.2 Extrusive Luxations

Extrusive luxation is a severe type of injury and requires immediate treatment. These teeth should be repositioned into the original site as soon as possible. Extrusive luxations occur when the tooth is partially displaced out of the socket or in a coronal direction. The patient will note occlusal changes, and severe mobility is possible. Following local anesthesia, the exposed surfaces of the tooth should be cleaned using saline or chlorhexidine, the tooth repositioned using digital pressure, and a flexible splint applied for 2 weeks [4].

4.3.2.3 Lateral Luxations

Lateral luxation is also a severe type of injury, which requires immediate treatment. Lateral luxations occur when the tooth has been laterally repositioned, usually with a concomitant alveolar process fracture. The tooth is often nonmobile due to the displacement of the tooth into the bone. For these luxations, the treatment of choice is to apply local anesthesia and reposition the tooth out of the bony lock using digital pressure or by using forceps. Once the location is verified using clinical and radiographic evidence, the tooth should be splinted for 4 weeks using a flexible splinting material [4] (◘ Fig. 4.7).

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig7_HTML.jpg
Fig. 4.7

Pre-operative images a, b of tooth #9, with lateral luxation and a concomitant alveolar process fracture. Post-operative image c after reduction. (Courtesy of Scott B. McClanahan, DDS, MS)

4.3.2.4 Avulsions

Avulsions occur when the tooth is completely displaced out of the socket and results in attachment damage due to the tearing of the periodontal ligament and possible crushing of the cementum. If the ligament does not dry out and is still attached to the root surface, the outcome is generally favorable [41, 42]. In cases where there is a large amount of damage, the area affected must be repaired by new tissue. In many cases, the cementoblasts are not able to mobilize as quickly as the osteoclasts present in the bony socket, and a common response in these cases is replacement of the root by the bone [43, 44]. This is described as replacement resorption and will be discussed in ► Sect. 4.4.4.

Treatment of this injury depends on the stage of development of the root and the speed at which the tooth is replanted [42].

4.3.2.5 Avulsion Immature Root

Avulsions that occur while the roots are still developing have a better chance for revascularization to occur than those whose roots have closed [45]. Root canal therapy should be delayed unless definitive signs of pathosis occur. When dealing with avulsions, the time the tooth has been exposed to the external environment is the most critical factor in the prognosis and treatment.

Ideally, the tooth will have been replanted immediately at the site of the accident. When the patient arrives at the office, the area should be inspected for proper position of the tooth, both visually and radiographically. A flexible splint should be applied and left in place for 1–2 weeks. Systemic antibiotic coverage with either tetracycline (if permanent tooth development is completed and there is no risk of staining) or amoxicillin (if permanent tooth buds are still growing) is recommended, along with verifying tetanus coverage and referring to the patient’s physician as needed. The patient should avoid any contact sports, should be on a soft food diet for 2 weeks, and should rinse with chlorhexidine bid for 1 week. Follow-up includes radiographic and clinical examination at 2 weeks, 4 weeks, 3 months, 6 months, and yearly to verify continued development of the root and monitor for possible pulpal necrosis or resorption [46] (◘ Figs. 4.8 and 4.9).

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig8_HTML.png
Fig. 4.8

Pre-operative image a of tooth #9, with history of recent avulsion and rigid splint placement at a hospital eg. EODT was <60 min. CBCT coronal b and axial c orthogonal planes showing presence of external resorption (white arrows), consistent with disclosure of previous traumas to area in past. Endodontic therapy was recommended and completed in multiple visits d. (Courtesy of Tyler Schuurmans, DDS, MS)

../images/335190_1_En_4_Chapter/335190_1_En_4_Fig9_HTML.png
Fig. 4.9

Three months post-op, pt reported to dental office for a second avulsion of tooth #9 with EODT >180 min ac. Pre-operative image d revealed marked incisal edge discrepancy and socket seen clinically as well with severe Class III mobility. An esthetic ribbon bridge was recommended, utilizing tooth #9 as a pontic gi, note the external resorption on the lingual e and buccal aspect f (white arrows). (Courtesy of Tyler Schuurmans, DDS, MS)

In cases where the extraoral time is over 60 min, it is presumed that the periodontal ligament is no longer viable [47] (◘ Fig. 4.9), and different surface treatments should be utilized to reduce the chance of resorption and increase the success of the replantation. Minocycline and doxycycline soaks prior to replantation have been shown in animal studies to increase the chance of revascularization [45, 48]. The tooth should then be gently rinsed and replanted, with splinting and follow-up instructions the same as if the tooth was replanted at the site [46].

4.3.2.6 Avulsion Mature Root

In a mature root, it is presumed that there is no chance for revascularization [48]. However, if the extraoral dry time is under 60 min, there is a chance for the PDL cells to remain viable. Endodontic treatment should be initiated within 7–10 days, utilizing an interappointment medicament for 2–4 weeks such as calcium hydroxide to reduce the incidence of resorption [49]. Although not available in the United States at this time, a combination of triamcinolone and demeclocycline has been utilized as an intracanal medicament for immediate treatment of avulsed teeth with high success rates [50]. Treatment for this type of injury is then identical to that of the avulsed tooth with an open apex.

If the avulsed tooth has been dry for greater than 60 min, it is assumed that the PDL has no viable cells and no regeneration is possible. The goal of treatment in these cases is to preserve the tooth in function while maintaining the alveolar contour with the knowledge that the ultimate fate of this tooth is ankylosis and resorption [46]. The final restoration in these cases will often be an implant or a fixed partial denture.

4.3.2.7 Intrusive Luxation

Intrusion of a tooth occurs when the tooth is forced into the socket. Intruded teeth will appear to be shorter than the surrounding teeth, are nonmobile, and will give an ankylosed metallic sound upon percussive tests. Intrusions are the most severe of the luxations due to the crushing of the blood supply and periodontal ligament. Treatment of these injuries depends on the stage of development of the root and the level of intrusion. In cases of incomplete root development and the intrusion is less than 7 mm, the tooth can be monitored for spontaneous eruption [4, 51]. In teeth with immature roots but over 7 mm of intrusion, orthodontic or surgical extrusion is recommended due to the severity of the intrusion.

If intrusion occurs in mature roots, root canal therapy should be initiated within 3–4 weeks after the trauma regardless of the level of intrusion due to the crushing of the blood supply [4, 51]. If the intrusion is minor (<3 mm), the clinician is advised to monitor the tooth for eruption. More severe intrusions of 3–7 mm should be orthodontically or surgically repositioned, and intrusions of greater than 7 mm should be surgically repositioned [4, 51, 52].

4.4 Resorption

Normal physiological root resorption occurs during the event of exfoliation in the primary dentition, whereas root resorption in the permanent dentition is the result of a pathological event, which may cause a progressive loss of tooth structure and could lead to premature loss. In order for pathological resorption to occur, two events must happen:

  1. 1.

    There is injury that removes or alters the protective covering of the dentin, the cementum on the external surface, or the odontoblast layer on the internal surface, which allows clastic cells from the circulatory system to access the dentin [53, 54].

     
  2. 2.

    Inflammation, from the pulp or periodontal tissue, must occur to the site of the unprotected root surface [55].

     

The primary etiology of injury to the non-mineralized, protective predentin or pre-cementum layers is from trauma [56], although heat from restorative procedures [57], excessive forces during orthodontics [58], and improper use of internal bleaching materials [59] have also been associated. The primary etiology of inflammation is from intrapulpal or periodontal infections, where adequate removal of bacteria can arrest the resorption process [60].

Although there is no universal classification system for resorption, generally it is classified by two broad categories, internal or external and the location, apical or cervical, for example. Resorption associated with a radiolucent pathosis is referred to as inflammatory. Often a sequela to avulsion is replacement resorption, where the cementum and dentin of the root is replaced by the bone. Schwartz recently classified pathologic resorption into four basic types [61].

Schwartz Classification of Dental Resorption

Aug 25, 2019 | Posted by in General Dentistry | Comments Off on of Endodontics in Dental Trauma
Premium Wordpress Themes by UFO Themes