Endodontics

Obliteration of pulp canai space after concussionand subiuxation: Endodontic considerationsMichiel de Cleen,

Concussion and subluxation injuries to permanent teeth lead to obliteration of the pulp canal space in 3%to 11 % of oases, depending on the severity of the injury and the developmental stage of the tooth.Obiiteration of the pulp canal space may make root canal treatment necessary because of the develop-ment of apicai periodontitis or for cosmetio reasons. If carefully executed, root canai treatment in teeth withan obliterated pulp canal space is highiy successful and may act as a basis for internai bleaching.(Quintessence Int 2002:33:661-669)

Key words: concussion, dental trauma, pulp space obiiteration, root canai treatment, subluxation

According to epidemiologic studies, between11-6% and 33.0% of all boys and between 3.6%

and 19.3% of all girls suffer dental trauma of varyingseverity'"^ before they are 12 years old. The most fre-quent consequences are coronal fractures.'* These areeasily recognizable by both the patients and theirparents and are easy to diagnose. Other forms of den-tal trauma, including ¡taxations, are also seldom mis-diagnosed. In many cases, immediately after thetrauma occurs, diagnosis is followed by the appropri-ate treatment.

Moderate injuries, such as concussion and subiuxa-tion, are associated with relatively minor symptoms inthe majority of cases; these injuries can, therefore, gounnoticed by the patient or the dentist, if the latter iseven consulted.^ In some cases, patients present yearsafter a traumatic accident with a single, discolored

'Private Practice. Amsterdam. The Netherlands.

Reprint requests: Di Michiel de Cleen, SchuDertstraat 40-1. NL-tO77 GVAmsterdam, The Netherlands.

Tills article has been translated trom "Obliteration des Pulpahohlraumsnach Konkussion j n d Subluiation—Endodontische Überlegungen."Erdodontie2O00:9:7-t7

tooth, which affects the esthetics of the dentition. Thisdiscoloration can be the result of obliteration of thepulp canal space; the puip cavity is filled with darktertiary dentin, resulting in a tooth with a less translu-cent appearance. In the present article, both the etiol-ogy of such obliteration and the treatment of affectedteeth are discussed.

PULPAL NECROSIS AND OBLITERATIONOF THE PULP CANAL SPACE AFTERCONCUSSION AND SUBLUXATION

Traumatic injuries to the teeth can be classified asthose affecting the soft tissues (periodontal tissues)and those affecting the hard tissues (enamel, dentin,and cement). Moderate injuries of the periodontiumcan be difficult for even a trained eye to spot.

These injuries include'':

1. Concussion: an injury to the supporting apparatusof the tooth that does not cause nonphysiologicloosening or displacement of the tooth but thatdoes result in a clear sensitivity to percussion.

2. Subiuxation: an injury to the supporting apparatusof the tooth that results in increased mobility butdoes not cause displacement of the tooth.

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Fig 1 Radiograph ol the mawiliary cen-trai Incisors of a 12-year-old boy Traumaled to the necrosis ot the puip of the rightoentral incisor and obiiteration of the puipoanai of the ieft centrai inoisor

The main causes of these injuries are falls whileplaying, sports, or assaults.^ Injuries to the teeth thatarise from endotracheal intubation are not unusual andcan also be the cause of subsequent dental problems.'

The damage caused to the periodontium by concus-sions and subluxations is generally low, transient, andwithout serious consequences, although signs of aslight résorption of the root surface may be seen insome cases. Generally, the pulp is also only slightlydamaged; the patient may feel some sensitivity whilechewing or when touching the tooth. A slight occiusaicorrection is usually sufficient to eliminate the pain.Nevertheless, in some cases, the injury to the pulp canresult in pulpal necrosis or an obliteration of the en-dodontic system (Fig 1), despite the absence of symp-toms immediately after the trauma.

Pulpal necrosis only occurs in 3% of teeth subjected

to concussion. Subluxations seem to affect the pulp toa higher degree; about 6% ofthe aftected pulps do notsurvive this trauma.^

After concussion or subluxation, affected teethoften do not react to sensitivity tests. Because of theinjury caused to the neurovascular bundle in the api-cal region, the innervation of the tooth is often af-fected. This injury can be reversible; it is possiblethat, after some weeks, sensitivity tests will show apositive result once again.^ For this reason, it is rec-ommended that the diagnosis of pulpal status bebased on a combination of sensitivity tests, coronaldiscoloration, radiographie analysis, and clinicalsymptoms.''

A diagnosis of pulpal necrosis is based on the ab-sence of reaction to sensitivity tests, the presence ofradiographie changes in the periapicai region and/orthe impairment of root development, and sensitivity topercussion. In these cases, cleaning and the subse-quent obturation of the pulp canal are indicated. Inteeth in which root formation is as yet incomplete,apexification must first be performed.'*'

The obliteration of the pulp space can be seen as aresponse to a more or less marked restriction of thepulp's neurovascular supply, which, after healing,leads to an increased deposition of dentin. The fre-quency of these obliterations depends on the extent ofthe luxation and the stage of the root formation.Obliterations of the endodontic system after a concus-sion occur in 3% of teeth with unformed roots and in7% of teeth with completely formed roots." The inci-dence of obliterations after subluxations is sligbtlyhigher; obliteration takes place in 11% of teeth withincomplete root formation and 8% of teeth with com-pleted root formation." After more accentuated luxa-tions (eg, intruded, extruded, and laterally luxatedteeth) both pulpal necrosis and obliteration of thepulp canal spaces are encountered much more fre-quently. In these cases, pulpal necrosis occurs moreoften in teeth with complete root formation,^ whilethe obliteration of the endodontic system is moreprevalent in teeth that, at the time of the trauma, haveincomplete root formation."

Generally, obliteration of the pulp canal spaces ad-vances in a eoronoapical direction: The first radio-graphic sign of obliteration is the decrease of the pulpchamber, followed hy a gradual narrowing of thewhole root canal (see case 1, Fig 2).

Andreasen and Andreasen* differentiate two typesof pulp canai space obhteration:

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1. Partial pulp canal obliteration (limited to the coro-nal part of the tooth)

2. Total pulp canal obliteration (extended to the coro-na! and radicular pulp canal spaces)

The histologie evaluation of pulp canals that havebeen radiographie ally diagnosed as heing totally oblit-erated almost always confirms tbe existence of a nar-row pulp canal.

A late complication after obliteration of the pulpcanal space is necrosis of the pulp. It is not yet clearhow pulpal necrosis arises in these cases, but caries,restorative treatments, and a second trauma may playa role. It can be assumed that the limited neurovascu-lar supply through the narrowed apical foramen andthe pulp canal cause the pulp to be more vulnerable tosuch damage. In recent clinical studies, the occurrenceof pulpal necrosis as a result of pulp canal obliterationwas found to be 1% after up to 10 years" and 8.5% ina period of up to 22 years.'^ According to anotherstudy, pulpal necrosis following obliteration of the en-dodontic system will only occur in teeth with a totalobliteration and, especially, in teeth affected by veryrapid pulp canal obliteration.'^

TREATMENT OF OBLITERATED PULP CANALS

Without a doubt, root canal treatment can help to pre-vent the development of apical periodontitis in teethwith a progressive obliteration of the pulp canal spaces.The low incidence of this late complication, however.Implies that endodontic treatment should never be per-formed as a prophylactic measure but rather should beused only in those cases where signs or symptoms ofapical periodonfitis appear. In these cases, root canaltreatment can be a real challenge, but it should not beconsidered impossible; it presents a long-term progno-sis of 80%" {see case 2, Fig 3). For discolored teeth inwhich the discoloration is not associated with apicalperiodontitis, root canal treatment can act as a basis foran internal bleaching of the crown (see case 3, Fig 4).

Endodontic treatments performed under these cir-cumstances pose the risk of perforating the root, acomplication that seriously affects the long-term prog-nosis of the tooth. The access cavity in these teethshould be similar to that opened in teeth with normalpulpal extension. This way, a large amount of dark ter-tiary dentin is removed, thereby contributing to tbetranslucency of the crown.

An access cavity of normai size and shape allowsthe use of long-necked round drills (eg. LN-drill,Dentsply/Maillefer), which are used parallel to theaxis of the tooth. If the access cavity is too small, thesedrills could be guided too far buccally, increasing therisk of perforation. In this stage, it is sometimes advis-able to take a radiograph with the drill placed insitu.'5 The instrument can be attached to the tooth bya piece of wax.

The use of magnification devices and transillumi-nation is helpful for locating the root canal.'^ Oncethe root canal is found, it is cleaned, shaped, andfilled in the conventional manner. The root canal fill-ing is shortened to a level 2 to 3 mm below the buc-cal cementoenamel junction and then covered withan impermeable material, such as glass-ionomer ce-ment. Sodium perborate can be placed to bleach thecrown, in accordance with the walking-bleachingtechnique."'

CASE REPORTS

Case 1

During a hockey game, a 15-year-old girl was hit in theface by a puck. At the time of the accident, she waswearing a custom-made mouthguard. Two days afterthe accident, her orthodontist diagnosed a concussionor subluxation of the maxillary left central and lateralincisors. Neither of the teeth reacted to cold stimuli.Because of persistent sensitivity in her teeth, she waseventually referred to an endodonfic clinic, where shepresented 5 weeks after the trauma (Figs 2a to 2k).

Case 2

A 31-year-old woman was referred for root canaltreatment and subsequent bleaching of her discoloredmaxillary central incisors. The anamnesis revealedthat she had been involved in a bicycle accident at theage of 12 years (Figs 3a to 3i).

Case 3

A 34-year-old woman was referred for bleacbing of herdiscolored maxillary right central incisor. The anamne-sis indicated that she had suffered an uncomplicatedcrown fracture at the age of 9 years (Figs 4a to 4f).

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Fig 2a Anterior view of a 15-year-oldgirl, 5 weeks after a sports accident. Allmaxillary anterior teetti react to cold stim-uli, with the exception of ihe left oentraland lateral incisors Ttie apical region ofttie maxiilary left central incisor is tenderwhen touched.

CASE1

Fig 2b Radiographs of the maxillary inoisors 5 weeks after the trauma, Tfie llaltenedapex ot the Iett lateral inoisor may be Ihe result of orthodontic movement of the tooth.

Fig 2c Radiographs taken 2 months afte' the trauma. There are no changes in the Fig 2d Radiograph taken 11 weeks afterreaction to cold stimuli; the Iett central incisor is still tencter on palpation. the (rauma. The Iett central incisor still

does still not react to the thermal sensitiv-ity test; on the left lateral incisor, the coldtest provokes slight sensitivity There is nolonger any sensitivity to palpation.

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Fig 2e (Top} Anterior view 4 months Fig 2g Radiograph taken 4 months atterafter the trauma.

Fig 2f (Bottom) Anterior view immedi-ately after endodontio ttierapy. The clean-ing of the pulp chamber resulted inmarked whitening ot the centrai incisorcrown.

ttie trauma The left lateral inoisor reactsto the sensilivity tests, but the centrai in-cisor does not. Because of the discol-oration of the crown, the previous markedtenderness on paipation, and the ab-sence of reaotion to the cold test, en-dodontic treatment is performed on thecentral incisor.

Fig 2h Woiking length assessment.Note both Ihe location and size ol the ac-cess oavity.

Fig 2, 2i Radiograph taken after endodon- Fig 2j Radiograph taken 6 months after Fig 2k Radiograph taken 2 years after' _pn, ̂ ^ completion of root canal treatment and 10 the trauma. The narrowing ot the pulpLI c a l i I ICI IL. 4^ . ' . _ _ J ^ i _ _ „ - ^ „ „ l * —™Í^— , - ^ l l - i ^ lilj-Lr-^l ¡í^i^lí^í^' i^-ic •-ii'-inonths after the trauma Narrowing of the canal Space m the lateral incisor has pro-

pulp canal space in the lateral inorsoi is gtessed.cleariy visible.

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CASE 2

Fig 3a Anterior view of a 31-year-Qldwoman who was involved in a bicycle ac-cident at the age of 12 years.

Fig 3b (Right) Diagnostic radiograph re-veaiing partial obliteration cf the en-dodontic system in the maxillary rightcentral incisor and total obliteration m theleft central incisor, in addition, the ieftcentral incisor exhibits penapical radiclu-cenoy.

Fig 3c Preparation for defermlnation ofthe working length.

Fig 3d (Right) Working length assess-ment. Note the size ol the endodontic ac-cess cavity.

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of the bieaching procedure.

Fig 3e Anterior view immediately after Fig 3f Anterior view atter two applicaroot canai treatment and before initiation tions cf sodium perborate over a 30-day

period (walking-bleaching technique)The patient was pleased with the result

Fig 3g (Right) Radiograph taken aftercompietion of root canal tteatment.

Fig 3h (Lett) Anterior view 1 year alterendodontic treatment and the bieaohingprocedure.

Fig 31 ¡Right) Radiograph taken 1 yearafter endodontic therapy.

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CASE 3

Fig 4a Anterior view of a 34-year-oldwoman who had suffered an uncompli-cated crown fracture at the age of 9years.

Fig 4c Preparation for estimation of theworking length.

Fig 4b Diagnostic radiograpn. Thereappear to be a totai obiiteration of the en-dodcntic system of the maxiliary rightcentrai incisor and flattening of the rootapex.

Fig 4e Anterior view after root canaitreatment and use of the walking-bieach-ing technique. The patient was referred toher reguiar dentist for repiacement of herresin composite restoration.

Fig 4d Working ienglh assessment Fig 4f Radiograph taken after comple-tion of root canai treatment.

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2. Jarvinen S, Fractured and avulsed permanent incisors inFinnish children. A retrospective study. Acta Odontol Scand1979:37:47-50.

3. Baghdady VS, Ghose LI, Enke H. Traumatized anteriorteeth in Iraqi and Sudanese children-A comparative study. JDent Res 1981;60;677-680.

4. Andreasen JO, Andreasen FM. Textbook and Color Atlas ofTraumatic injuries to the Teeth, ed 3. Copenhagen: Munks-gaard, 1994.

5. Ebeleseder KA, Glockner K. Diagnostik des dentalenTraumas-Erstuntersuchung und Verletzungsarten. Endo-dontiel999;8:101-lU,

6. Crona-Larsson G, Norén JG. Luxation injuries to perma-nent teeth-A retrospective study of etiological factors.Endod Dent Traumatol 19S9;5;176-179,

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8. Andreasen FM, Vestergaard Pedersen B, Prognosis of lux-ated permanent teeth-Development of pulp necrosis.Endod Dent Traumatol 1985; 1:207-220.

9, Hcrforth VA, Zur Frage der Pulpavitalität nach Frontzahn-trauma bei lugendiichen-cine Longitudinaluntersuchung.Dtsch Zahnärztl Z 1976;31:938-946.

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12. Robertson A, Andreasen PM, Bergenholtz G, Andreasen JO,Noren JG, Incidence of pulp necrosis subsequent to canalobliteration from trauma to permanent teeth. J Endod 1996;22:557-560.

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14. Cvek M, Granath L-E, Lundberg M. Failures and healing inendodonticalty treated non-vital anterior teeth with post-traumatically reduced pulpal lumen. Acta Odontol ScandI982;40:223-228,

15. Peters LB. Preparation der endod on tischen Zugangskavitätund Darstellung der Kanäle. 1. Schneidezähne und Eck-zähne. Endodontie 1992;l:57-64.

16. Barthel CR. Atiologie und Therapie von Zähnen mit ohli-teriertem Pulpahohlraum. Endodontie 1999:8;21-31,

17 Weiger R, Bleichen verfärbtcr wurzelkanalbehandelterZähne, Endodontie 1992:1:109-116.

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