The endodontic management of traumatized permanent anterior teeth: a review

The endodontic management of traumatized

permanent anterior teeth has been reviewed and

recommendations have been presented for each type of

injury. The management of dental injuries is an

evolving science. Some traditional treatment options

have stood the test of time and are still valid to this day.

Others have been reviewed and modified with the

passage of time, as new science and new materials

evolve to prove, disprove or facilitate approaches to the

management of these injuries. Practitioners need to

always be aware of changes that occur from time to

The immature tooth with pulp necrosis and infection

A large number of different apical configurations can

result if an immature tooth with an open apex is

traumatized. Continued root development, apical

doming, in-growth of bone, and aberrant root formation

have all been reported. Repair appears to be more

related to the creation of an environment conducive to

repair rather than the type of medicament used.

The diagnosis of pulp necrosis and infection in an

immature tooth is often difficult. Radiographic changes

may be difficult to see. The clinician often has to rely

on an assessment of other signs and symptoms, such as

the presence of acute or chronic pain, tenderness to

percussion, increased mobility, discolouration of the

crown, or the presence of a draining sinus tract.

Endodontic treatment of teeth with pulp canal calcification

Treatment of teeth with pulp canal calcification

presents a dilemma. A number of authors have

proposed that for endodontic technical reasons and for

prevention of tooth discolouration, these teeth should

be root filled once the calcification process is detected.

Endodontic procedures are certainly easier if under-taken at this stage. 

However, most of the recent

literature indicates that endodontic treatment is

unnecessary unless the tooth is symptomatic or there is

radiographic evidence of pulp necrosis and infection–

i.e., a periapical radiolucency. Proponents of the latter

course of action base their opinions on histological

studies which indicate that the calcific changes do not

warrant pulp extirpation and that a remnant of the

canal is always present.

Pulp canal calcification

Calcification of the root canal (commonly referred to

as pulp canal obliteration, or PCO) is a common sequel

following luxation injuries to permanent teeth,

particularly teeth that have been injured before their

root formation has been completed.

Abbott and Yu have discussed the terminology regarding this condition

and they have recommended the use of the term

“calcification” (rather than “obliteration”) as it more

accurately describes what is happening, or what has

happened, within the root canal. Obliteration implies

complete blocking or elimination of the canal which is

unlikely, even in a tooth that radiographically appears

to have no root canal present.

Clinically, a yellowish discolouration of the crown

may be observed. Pulp canal calcification is also a

common occurrence in root-fractured teeth occurring

principally in the region of the fracture, and in the

apical fragment. It may also occur in teeth associated

with alveolar and jaw fractures. 

Endodontic treatment of teeth with resorptive defects

Surface resorption is self-limiting and does not

generally require treatment. Frequent clinical and

radiographic review is necessary, however, to confirm

that inflammatory and replacement resorption are not

occurring in these teeth.

Where resorption has been initiated in traumatized

teeth, replacement resorption cannot be treated

effectively. Nevertheless, as replacement and

inflammatory root resorption can occur together,

endodontic therapy to remove necrotic and infected

pulps from resorbing teeth is warranted. As an interim

measure the teeth can be dressed with a cortico-steroid/

antibiotic paste or calcium hydroxide, or it can

be root filled. Each case has to be treated on its merits.

Treatment of resorbing traumatized ankylosed anterior

teeth often requires multi-specialty treatment planning.

Before extensive endodontic management is

contemplated, the options of extraction, prosthetic

replacement, maintenance of the space for future

prosthetic replacement, orthodontic space closure,

Root resorption

Resorption is a common sequel to dental trauma and

may be caused directly by the traumatic incident or

indirectly through subsequent infection. Andreasen has

described three types of resorption following trauma:

surface resorption, replacement root resorption and

inflammatory root resorption.

Root resorption has also been described as being 

as ankylosis-related and

infection related.

Heithersay has extensively reviewed

root resorption and proposed a new system of

classification of these defects, as well as describing a

range of treatment options for these lesions.

Endodontic treatment of avulsed teeth

It has been previously recommended that in mature

teeth, endodontic therapy should be commenced seven

to 10 days following replantation.

However, it would now seem that pulp extirpation should be

carried out as soon as possible to prevent the initiation

of inflammatory root resorption.

The canal should be

debrided, dressed with a corticosteroid/antibiotic or

calcium hydroxide paste preparation for one to three

months, after which time the canal can be obturated

and the access cavity sealed. Follow-up radiographs

should be taken at regular intervals of one, three, six

and 12 months.

Stage of root development

The replantation of avulsed teeth with immature root

development has been the subject of review.

As the pulps in a small percentage of replanted immature teeth

may survive, it is recommended that endodontic

treatment should be delayed in these teeth to establish

whether root formation continues. Revascularization

appears inversely proportional to root length. However,

external inflammatory resorption progresses very

rapidly in immature tooth roots. Thus, regular clinical

and radiographic examinations at short intervals are

recommended to establish whether resorptive processes

have been initiated. Great care should be taken in

Contamination of the root surface

Contamination of the root surface has been found to

be a prognostic indicator for root resorption. The

prevalence of resorption in teeth replanted without

visible contamination has been reported to be 57 per

cent, whereas 75 per cent of teeth that were washed and

87 per cent of those that were rubbed clean underwent

resorption. When teeth were replanted with visible

contamination still present, 100 per cent exhibited

resorption.

Effect of endodontic therapy

Endodontic therapy involving obturation with gutta-percha or 
the placement of calcium hydroxide dressings
at the time of replantation delays periodontal healing
and hastens replacement resorption in mature teeth.
Endodontic therapy should be delayed until the initial
period of soft tissue healing takes place.

However,since revascularization rarely occurs in mature teeth,
and as pulp necrosis contributes to inflammatory root
resorption, it has been recommended that in mature
teeth pulps should be extirpated as soon as possible

Antibiotic therapy

Systemic administration of antibiotics is generally

recommended in order to prevent the harmful effects of

bacterial contamination, although the evidence to

support this is limited. Experimental animal studies

have reported that systemic antibiotics decrease the

incidence of inflammatory root resorption but have a

limited, or no, effect on the pulp.

Recent research has

focused on the effect of topical antibiotic therapy with

promising results in animal models. Topical doxycyline

and minocyline applied to the root surface before

replantation have been found to increase the chance of

pulp revascularization in dogs and to decrease the

chance of inflammatory root resorption and ankylosis

Socket preparation

Transplantation experiments indicate that the vitality

and integrity of the tooth socket is a factor to be noted

in the development of root resorption, although the

length of time out of the socket appears to be more

critical. Curettage of the socket is not necessary,

although doing so has no major effect on the replanted

tooth. However, gentle irrigation of the socket to

remove any blood clots prior to replantation is thought

to be better than curettage and may be necessary if

there has been a time delay in replanting the tooth.

Splinting

Splinting procedures do not significantly improve

periodontal healing. Longer splinting times (greater

than 10 days) tend to hasten the resorption process,

particularly if inflexible splints are used. It is probable

that functional stimulation plays a role in repair.

Storage medium

As most avulsed teeth are not replanted at the site of

the injury and few patients can receive treatment within

15 minutes, a suitable storage medium to maintain the

health of the periodontal ligament cells is critical. In

studying periodontal ligament healing associated with

replanted teeth in monkeys, 

Andreasen varied the extra-alveolar time periods and the storage media. He

established that if the teeth cannot be replanted

immediately, then storage in saliva or saline solutions

significantly reduced the amount of root resorption.

Extra-oral time

It has been clearly established that the length of

extra-oral dry time and the stage of root development

are the most critical factors associated with root

resorption.

The critical dry time where a statistically

significant increase in root resorption was observed

was 15 minutes in one study although just five minutes

of dry time was sufficient to increase the incidence of

resorption in another study.

Teeth that are replanted

immediately have the best long-term prognosis and the

least incidence of root resorption. 

One animal study

Vitality of the periodontal ligament and tooth socket

Vitality of the periodontal ligament cells is a factor

that greatly affects the healing of replanted teeth. When

the vitality of the periodontal ligament cells is lost,

replacement resorption usually occurs. There is a

relationship between the total area of root surface

where the cells have become necrotic and the amount of

replacement resorption generated.

Avulsion

Avulsion or exarticulation occurs when a traumatic

injury totally displaces a tooth from the socket.

Treatment of the avulsed tooth is one area in dentistry

where recent research has been applied to greatly

improve the prognosis for the long-term retention of

these teeth. Andreasen recently reviewed tooth avulsion

and replantation.

Although the prognosis for an

avulsed tooth must always be guarded, replantation as

soon as possible followed by a brief period of flexible

Endodontic treatment of luxation injuries

It is generally agreed that for most luxation injuries,

with the exception of intrusive injuries in mature teeth,

endodontic therapy should be postponed until

additional signs of necrosis appear such as colour

change and radiographic changes, both in the tooth and

the surrounding bone.

Should the pulp become

necrotic and infected, treatment is dependent upon the

state of closure of the apex. If apical maturation is

complete, standard endodontic treatment is indicated.

Should apical development be incomplete, apexification

procedures utilizing calcium hydroxide

and/or MTA are indicated.

The first concern in the treatment of luxation injuries

should be the repair of the periodontium. Soft tissue

injuries and repositioning should be treated before

endodontic procedures are contemplated. 

Endodontic treatment need not be considered for

concussion and subluxation injuries until there are

signs of pulp necrosis. However, judicious grinding may

be necessary to free the tooth from occlusion. Frequent

radiographic examinations and pulp sensibility testing

are needed during the follow-up period. 

If the root is extruded, careful monitoring of the

tooth must be undertaken after repositioning and a

period of splinting of two weeks duration. In the event

that there has been a delay in repositioning the teeth,

gentle orthodontic treatment may be needed to

reposition them. Radiographic examination and pulp

sensibility testing should be carried out at regular

intervals such as: two weeks, one month, two months,

six months, 12 months and then on a yearly basis for a

number of years.

Endodontic therapy should be commenced immediately there is evidence of pulp

necrosis or root resorption. While immature teeth can

revascularize and can continue root development,

which can be seen radiographically, it is not prudent to

delay treatment in immature teeth that show any sign

of root resorption, as inflammatory root resorption can

occur very rapidly. A delay in treatment even for one

week can result in loss of substantial tooth structure. In

these teeth, pulp extirpation and root filling after

calcium hydroxide or corticosteroid/antibiotic therapy

is the treatment of choice. In mature teeth, endodontic

therapy should be undertaken where there is clinical

and/or radiographic evidence of pulp necrosis and

infection, or root resorption. Continued lack of

reaction to pulp sensibility testing is usually indicative

of pulp necrosis, unless there is radiographic evidence

of ongoing calcific changes in the root canal system.

Where a tooth has been laterally luxated, it should be

repositioned without delay. Again, endodontic therapy

is carried out only when there are signs of pulp necrosis

or root resorption. Lateral luxation does not occur

without fracture of the alveolar socket. Immediate

repositioning, with forceps if necessary, and splinting 

is therefore recommended. Splinting should be of 

four weeks duration to allow the fractured bone to

heal.

Treatment of intruded teeth can be a challenge. Pulp

necrosis almost invariably occurs in intruded mature

teeth and treatment can complicated by the fact

that most intruded teeth are also associated with crown

fractures.

Subsequent re-eruption, if it occurs, may be

very slow during which time root resorption may

become advanced. Delayed repositioning leaves roots in

intimate contact with bone and this influences the onset

of replacement resorption. Thus, mature teeth should

be repositioned as soon as possible and the pulps

removed immediately, or as soon as possible once the

soft tissues have healed sufficiently to do so, to help

prevent the onset of inflammatory root resorption.

22,74

Repositioning intruded teeth is a priority and can

occur through spontaneous re-eruption or it may

require surgical or orthodontic repositioning. Surgical

repositioning or orthodontic repositioning is the

treatment of choice for mature teeth in adults (>17 years

of age).

A recent review found no significant

difference in healing between surgical or orthodontic

repositioning of permanent intruded teeth.

Surgical repositioning is preferred where there is complete

intrusion and gingival healing may prevent re-eruption

or complicate orthodontic repositioning. A surgical

technique may be more practical for multiple intrusions

where orthodontic anchorage may be an issue. Care

must be taken in repositioning these teeth to ensure that

the hard tissues are brought down with the tooth and

that the soft tissues are sutured into place if necessary.

While orthodontic extrusion has been advocated, it is

not always possible as the teeth are often wedged firmly

into the bone and attempts to extrude the tooth can

lead to intrusion of adjacent teeth. Each situation has to

be assessed on its merits and on the state of

development of the tooth. Mature teeth that are firmly

wedged into the alveolus should be immediately

repositioned surgically. In mature teeth, urgent

endodontic management should be commenced as soon

as practical following repositioning.

Intruded teeth with open apices are more likely to

erupt spontaneously and less likely to develop problems

of an endodontic origin. As immature intruded teeth

can spontaneously reposition themselves in the arch

and significantly better healing occurs when this

happens, it has been suggested that treatment be

delayed for these teeth.

However, if spontaneous repositioning does not appear to be occurring quickly,

immature teeth can be brought down by orthodontic or

surgical means as soon as possible after trauma. There

is an argument for surgically disimpacting these

intruded immature teeth from the alveolus to assist

with re-eruption. Regular radiographic follow-up at

two weeks, one month, two months, six months and

yearly is essential for these teeth as root resorption can

occur rapidly in immature teeth.

Should any resorption be detected, pulpectomy and treatment with calcium

hydroxide or a corticosteroid/antibiotic paste prior to

root filling procedures should be urgently carried out.

Surgical exposure of the intruded immature 

teeth to permit endodontic therapy has been proposed

to avoid delay in endodontic treatment and the

development of inflammatory root resorption.

Intrusive luxation

In intrusive luxation the teeth are forcefully intruded

into the bone. Because of the direction of displacement,

a comminuting fracture of the socket also occurs. The

frequency of pulp necrosis is very high. At least 85–95

per cent of mature intruded teeth become necrotic.

Pulp canal calcification and progressive root resorption

are expected to occur in 4 and 48 per cent of cases,

respectively.

Treatment of intruded teeth can be complicated by

the fact that most intruded teeth are also associated

with crown fractures.

Delayed repositioning leaves

roots in intimate contact with bone and this influences

the onset of replacement resorption. Thus, mature teeth

should be repositioned as soon as possible and the

pulps removed immediately or as soon as possible once

the soft tissues have healed sufficiently to do so, in

order to help prevent the onset of inflammatory root

resorption.

Although immediate (i.e., surgical)

repositioning is the treatment of choice for mature teeth

in adults (>17 years of age), orthodontic repositioning

is another option for managing such injuries.

Intruded immature teeth behave somewhat differently

and more treatment options are available. The apex is

open and the bone in children is softer and more

malleable. In these teeth, the extent of the intrusion and

the presence of associated crown fractures are

important prognostic considerations. All intruded teeth

in a paediatric population survived for five years if the

intrusion was less than 3mm, 90 per cent if the

intrusion was between 3mm and 6mm, and only 45 per

cent if the intrusion was greater than 6mm.

Almost all surviving intruded immature teeth undergo pulp canal

calcification. Pulp necrosis is usually diagnosed within

six months but may develop up to two years later in

open-apex teeth.

In open-apex teeth, awaiting

spontaneous eruption has been reported to lead to the

best outcomes.

However, careful monitoring must be

carried out to ensure that resorptive defects are detected

and treated early. Root resorption has been reported to

occur in a large number of cases.

It can be seen from the above that luxation injuries

result in a much higher incidence of pulp necrosis than

do injuries involving fracture of the teeth. As would be

expected, the risk of pulp necrosis increased with the

extent of the injury; concussion and subluxation

represent the least risk, followed in ascending order by

extrusive, lateral and intrusive luxation. Intrusive

luxation appears to be the most serious type of injury

with regard to the development of pulp necrosis and the

development of root resorption. Teeth that have been

luxated should be identified and observed over a long

period. Teeth with completed root formation

demonstrate a greater risk of pulp necrosis than teeth

with incomplete root formation. In particular,

development of pulp necrosis after injury has been

shown to be significantly related to the diameter of the

apical foramen.

For extruded and laterally luxated

teeth, the smaller the diameter, the greater the

probability of pulp necrosis. Intruded teeth with

incomplete root development are associated with a

much higher probability of pulp survival than teeth

with complete root development.

The diagnosis of pulp necrosis following luxation

injury needs careful attention. The initial condition of

the pulp may be one in which only the nerve supply has

been damaged and the potential for revascularization

without concomitant neuron-regeneration cannot be

dismissed. The extent of apical displacement has been

found to be significantly related to the incidence of pulp

necrosis for intrusive luxations but not extrusive and

lateral luxations.

Sensibility tests, though useful,

may be unreliable in luxated teeth. Discolouration and

periapical radiolucent lesions are the most important

diagnostic features to be noted for subluxation,

extrusive luxation and lateral luxation. The presence of

inflammatory root resorption is an important factor in

establishing the diagnosis of pulp necrosis and infection

in replanted and intruded teeth,

and pulp extirpation

must be carried out at the earliest radiographic sign of

this process occurring.

There is one factor that should not be overlooked

when assessing radiographic changes in luxated teeth.

While a rare occurrence, transient apical breakdown is

believed to be a non-infected apical remodeling process,

which can mimic pulp necrosis radiographically and in

clinical tests and observations. Andreason

examined 637 cases of luxated teeth and identified this process in

4.2 per cent of teeth. The majority of these teeth

demonstrated a periapical radiolucency, as well as

colour and/or electrometric sensibility changes. All

teeth showed resorptive widening of the apical

foramen. All signs and symptoms later returned to

normal. Recognition of transient apical breakdown is

important if unnecessary endodontic treatment is to be

prevented. Transient apical breakdown is more

common in mild luxation injuries in fully formed or

almost fully formed teeth. A case can be made for

observing asymptomatic teeth with early signs of pulp

necrosis in selected cases, but only where the clinician

is absolutely confident that the patient is likely to

comply with frequent recall investigations. Continued

root development and calcification within the canal

must be regarded as a positive indication of a vital pulp

even in the absence of a positive response to pulp

sensibility testing. Regular radiographic examination is

necessary. Endodontic therapy must be commenced at

the first radiographic evidence of inflammatory root

resorption.

Lateral luxation

Lateral luxation represents eccentric displacement of
the tooth in its socket. This type of luxation is
accompanied by fracture or comminution of the socket
wall and the tooth is usually locked into the new
position. The incidence of pulp necrosis in laterally
luxated teeth in a paediatric population was found to
be 40 per cent, with an additional 40 per cent of teeth
demonstrating pulp canal calcification.