Revascularization of Immature Permanent Incisors After Severe Extrusive Luxation Injury

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Revascularization of Immature Permanent Incisors after

Severe Extrusive Luxation Injury

Zafer C. Cehreli, DDS, PhD; Sezgi Sara, DDS; Burak Aksoy, DDS

Posted on January 19, 2012

Tags:childrenendodonticsinjurytreatment

Cite this as: J Can Dent Assoc 2012;78:c4

Abstract

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete

apical closure. In this report, we describe the management of severely extruded immaturemaxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An8.5-year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a

fall was provided emergency treatment consisting of reduction of the dislodged labial cortical

bone and repositioning of the central incisors, which had suffered extrusive luxation. When he

presented with spontaneous pain involving the traumatized incisors a week later, the teeth weretreated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks

of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin

composite. Complete periradicular healing was observed after 3 months, followed by progressivethickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of

the regenerative treatment as a viable alternative to conventional apexification in endodontically

involved, traumatized immature teeth.

Introduction

Extrusion is an injury characterized by partial axial displacement of a tooth.1

Clinically, the

affected tooth appears elongated, is usually displaced in the palatal direction and demonstratesexcessive mobility.

2,3Radiographically, extruded teeth appear to have an increased periodontal

ligament space. Based on severance of the periodontal ligament that has not yet been exposed to

desiccation or disarticulation of the tooth from the blood supply, Andreasen4

described extrusive

luxation as partial avulsion. According to Lee and colleagues,3

this term is useful in terms oftreatment approach, as the pulpal outcome of severe extrusion may be comparable to that of a

replanted tooth.

The stage of apical development is a key factor in pulp healing after extrusive luxation.3,5,6

In

teeth with open apices, the pulp has greater potential for healing, commonly followed by pulp

canal obliteration; in patients with closed apices, the likelihood of pulp revascularization is low,usually leading to pulp necrosis.

1,3,5,6Once pulp necrosis is diagnosed, endodontic therapy should
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be initiated to eliminate infection and facilitate healing and retention of the tooth.3

If root

development is incomplete, apexification is indicated to induce formation of a calcific barrier at

the apex. However, this technique has several disadvantages, including up to 24 months oftreatment, which often requires multiple visits and renewal of the intracanal dressing.

7,8Apical

closure is unpredictable,9

and the tooth is susceptible to root fracture after prolonged exposure to

calcium hydroxide (Ca(OH)2).

10,11

Because of these concerns, the traditional Ca(OH)2-basedapexification procedure has been modified by the introduction of an artificial apical barrier usingmineral trioxide aggregate (MTA).

1215Obturation of open apices with MTA plugs significantly

reduces treatment time and results in favourable healing of periradicular tissues.12,14,16,17

However, MTA plugs cannot stimulate physiologic apical closure and thickening of radiculardentin, leaving the tooths structural integrity compromised.

18,19

Revascularization is an emerging regenerative endodontic treatment approach that aims to allowcontinuation of root development and tissue regeneration in immature necrotic teeth.

20,21The

root canal is disinfected with sodium hypochlorite, followed by placement of an intracanal

medicament, such as calcium hydroxide or a combination of ciprofloxacin, metronidazole and

minocycline.

22

After disinfection, the antibiotic paste is removed and apical bleeding is inducedto form a blood clot below the coronal level. The root canal orifice is then sealed with MTA, and

the tooth crown is restored permanently.

This protocol has been successful, as evidenced by increased root length, thickening of the root

walls and apical closure of varying degrees.2328

In the following case, we describe the

management of severely extruded immature maxillary incisors and the outcome ofrevascularization in the treatment of pulp necrosis subsequent to the trauma.

Case Report

A healthy 8.5-year-old boy was admitted to the pediatric dentistry clinic 6 hours after a fall in hisschoolyard. Reportedly, an emergency examination had been carried out by a hospital

pediatrician, who found the patient to be free of neurologic and general physical symptoms andreferred him for management of dentoalveolar trauma.

The child was unable to close his mouth or speak properly because of severely displaced

maxillary central incisors, evident on extraoral view (Fig. 1a). Intraoral examination showed

severe extrusive luxation of the incisors along with a fractured labial cortical bone (Fig. 1b). The

teeth were excessively mobile and the maxillary right central incisor showed pronounceddisplacement in the palatal direction. The palatal segment of the alveolar bone was slightly

mobile on palpation, but did not appear to be dislodged. The neighbouring lateral incisors

displayed normal mobility. The attached gingiva distal to the right lateral incisor was lacerated(Fig. 1b). A periapical radiograph revealed increased apical periodontal ligament space in bothincisors, along with palatal displacement of the right central incisor (Fig. 1c). In both teeth, root

development was incomplete, and wide root canals and open apices were evident.

Following removal of the blood clot with copious saline irrigation (Fig. 1d), the dislodged buccal

cortical bone was gently repositioned. The extruded incisors were then meticulously repositionedby conventional digital maneuver, with no sign of resistance caused by a clot blockage. A semi-


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rigid splint made of 0.9-mm monofilament fishing line was bonded to the lateral and central

incisors using acid-etch composite resin (Fig. 1e). After suturing of soft tissue lacerations, a

radiograph was taken to confirm correct reduction and repositioning (Fig. 1f). The patient wasprescribed amoxicillin and ibuprofen, and scheduled for a follow-up visit.


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Figure 1: Initial examination of patient. a) Extraoral view, demonstrating the extent of jaw

closure; b) intraoral and c) radiographic views of extruded incisors; d) intraoral view following

removal of the blood clot with saline irrigation; e) view of the incisors after reduction, splintingand suturing; f) radiographic view of the incisors after repositioning, revealing the wide root

canals and open apices.

A week later, the patient returned with severe spontaneous pain involving the traumatized

incisors. The teeth were tender on palpation, and radiographic examination revealed periapical

radiolucency. Because of the patients incomplete root development and wide open apices,traditional endodontic therapy using Ca(OH)2-based apexification or placement of an apical

barrier with MTA would seriously compromise the structural integrity of the tooth. Therefore,regenerative endodontic treatment of the affected incisors was considered. After comprehensive

discussion of the risks and possible outcomes of this treatment and the treatment plan in case offailure, the consent of the patient and parents was obtained and treatment was initiated at the

same visit.

After anesthesia, the pulp chambers were accessed. Isolation was achieved using cotton rolls and

gauze, as a rubber dam could not be placed in the presence of the trauma splint. Each root canalorifice was gently irrigated with 10 mL of 2.5% sodium hypochlorite (NaOCl) without

instrumentation. Ca(OH)2 powder (Merck, Darmstadt, Germany) was mixed with sterile saline in

a 3:1 ratio to produce a thick, homogeneous paste. The mixture was placed in the pulp chamber

using a plastic carrier and loosely packed into the coronal portion of the root canals with moistcotton pellets. Finally, the access cavity was sealed with Cavit (3M ESPE, Seefeld, Germany)

(Fig. 2a). A week later, the patient was recalled for removal of the trauma splint and, 3 weeks

later, for evaluation of the intracanal medication.

After 3 weeks, both teeth were asymptomatic. They were anesthetized using 2% mepivacaine

(Citanest, AstraZeneca, UK) without a vasoconstrictor, isolated with a rubber dam and

reaccessed. The Ca(OH)2 paste was removed with copious 2.5% NaOCl irrigation, and the root


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canals received a final irrigation with 10 mL sterile saline and were dried. Apical bleeding was

induced by gentle irritation using size 15 K-files. After a blood clot had formed, MTA (Dentsply

Tulsa Dental, Tulsa, OK) was prepared according to the manufacturers instructions and gentlyadapted over the blood clot. A wet cotton pellet was placed over the MTA, and the access cavity

was temporarily restored with conventional glass ionomer cement. Final resin composite

restorations were placed 1 week later (Fig. 2b), and the patient was scheduled for regular follow-up visits.

The teeth remained asymptomatic during the 18-month evaluation period. At 3 months, the teethshowed complete periapical healing and, thereafter, root development and closure of the apices

continued (Fig. 2c).

To quantify the increase in root width and length, the radiographs obtained immediately after

treatment and 18 months later were converted to 32-bit TIFF files using ImageJ analysis program

(v.1.44p, National Institutes of Health, Bethesda, MD). The TurboReg plug-in (Biomedical

Imaging Group, Swiss Federal Institute of Technology, Lausanne, Switzerland)29

was used to

mathematically align the two images as described by Bose and colleagues.

28

Because the 18-month radiograph showed less distortion, it was used as the source image, while the

postoperative radiograph, which required correction, was used as the target image.28

Followingalignment of the images using TurboReg (Fig. 2d), a scale was added, and root lengths and root

wall thicknesses were measured.28

This revealed an increase of 18.16% and 17.14% in the root

lengths and 40.54% and 75.64% in the root widths of the right and left incisors, respectively.


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Figure 2:a) Radiographic view of the teeth after intracanal application of calcium hydroxide

(Ca(OH)2) paste; periradicular radiolucencies are evident in both roots. b) Periapical radiograph

showing the coronal mineral trioxide aggregate (MTA) barrier and final composite restoration. c)Radiographic view at 18 months follow-up, demonstrating narrowing of root canal in the apical

third and thickening of the lateral walls. A normal bony architecture at the periradicular region is

evident. d) Image b after correction (alignment) with ImageJ and the TurboReg plugin using c asthe source image for mathematical correction.

At 12 months, a positive response to a cold test was first observed, but the response of both teethto electric pulp testing (EPT) was inconsistent. At 18 months, response to cold testing was still

positive and both teeth showed a consistent, delayed response to EPT. The patient has beenattending regular follow-up appointments; his teeth have remained asymptomatic, with normal

mobility and gingiva in good condition.

Discussion

Pulp necrosis is a relatively uncommon sequel to extrusive luxation in immature teeth with wide-

open apices,5

because of the high likelihood of revascularization and subsequent root

development in these teeth. However, the risk increases significantly in the case of severeextrusion

3and, if pulp necrosis occurs, it is likely to be an early event.

3,5,30

Regenerative endodontic techniques may enhance continued root development21

and, therefore,offer an alternative approach to the management of traumatized immature permanent teeth with

pulp necrosis and periradicular infection.24,31

A growing body of evidence supports the

possibility of residual viable pulpal tissue in the wide root canal or apical region of necroticimmature teeth, which may survive the infection and allow continued apical development.

25,32,33

Stem cells from the apical papilla may also survive infection, because of their proximity to the

periapical tissues.26,32,33

Following proper endodontic disinfection, these cells may differentiate

under the influence of surviving epithelial cells of Hertwigs root sheath and initiate continued


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root development.26,33

Once the regenerative process is induced, the presence of a wide apical

foramen and root canal enhances the ingrowth of small blood vessels and regenerated tissues.26

In the revascularization protocol, infected root canals should be treated as conservatively as

possible.20,25,31

This is best achieved by copious irrigation with 2.5%5.25% NaOCl and no

instrumentation. At the same appointment, intracanal medication is put in place to disinfect theroot canal and left for 34 weeks. Previous reports have demonstrated the effectiveness of a

triple antibiotic paste consisting of metronidazole, ciprofloxacin and minocycline in the

disinfection of infected root canals,22,34

including those of immature teeth with apicalperiodontitis.

25,35The main disadvantage of this paste is minocycline-induced crown

discoloration,36,37

which might be reduced, but not prevented by prior sealing of the coronal

dentin with bonding agents.37

Ca(OH)2 has also been used successfully for disinfection of root canals before

revascularization.23,26,28

Bose and colleagues28

showed that placement of Ca(OH)2 in the coronal

half of the root canal contributed to a significant increase in root length and wall thickness,

comparable to that achieved with the triple antibiotic paste.

In the current case, the teeth were asymptomatic after treatment with Ca(OH)2: continuing rootdevelopment was observed, symptoms of infection were absent and no crown discoloration

occurred. In a retrospective study, Chueh and colleagues26

showed a high rate of progressive

calcification of the root canal space in teeth medicated with Ca(OH)2, suggesting that rootdevelopment induced by regenerative endodontic treatment may not follow a natural pattern.

Thus, despite the absence of root canal obliteration in the current case, progressive calcification

may occur in the longer run.

Previous studies of the revascularization procedure in traumatized, immature incisors have

reported a lack of sensitivity to both cold testing and EPT.

24,30,38

In the absence of histologic datafrom humans, the reasons for both positive and negative responses to thermal and electricalstimuli should be interpreted with caution, as lack of response could merely be a result of the

thickness of the MTA and restorative materials preventing stimulation of vital tissues within the

root canal.39

The use of a collagen matrix to control the thickness of the coronal MTA barrier30

and placement of the MTA barrier close to the cementoenamel level

39might increase the

likelihood of a positive response, provided that the regenerated tissue in the root canal contains

nerves. Based on these considerations, the inconsistent responses of the extruded incisors to EPTin contrast to cold testing might have resulted from the thick MTA barriers, which occupied

almost half the length of the root canal.

The favourable short-term results in this case of severe extrusive luxation show that regenerative

endodontic treatment of pulpally involved traumatized immature teeth is a viable alternative to

apexification or artificial apical barrier techniques. Although the nature of the regenerated tissue

within the root canal is yet to be elucidated in humans, it is evident that this technique can allowfor continued root development and apical closure. More clinical data is required to confirm the

predictability of this approach.

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Revascularization of Immature Permanent Incisors After Severe Extrusive Luxation Injury