Epidemiological investigations reveal a high
incidence of dental injuries that may be related to predisposing factors, but
they are primarily caused by accidents.1-6 The majority of dental
injuries involve the anterior teeth and generally affect a single tooth,
although certain types of trauma favor multiple injuries. Most reports indicate
precise gender and age distribution as well as seasonal variations.
Injuries are divided
into hard or periodontal tissue injuries. According to Andreasen,7
luxation injuries are defined by the following diagnostic criteria:
-- Periodontal injury that causes loosening but not displacement of the tooth.
-- Forced impaction of the tooth into the alveolar socket.
-- Partial displacement of the tooth from its socket.
luxation -- Forced movement of the tooth laterally.
-- Total luxation of the tooth.
Although luxation injuries may affect the
periodontal structures and the blood supply of the pulp, the frequency of
periodontal ligament (PDL) complications and pulp necrosis is rather rare in
subluxation, as it does not imply displacement of a tooth in its alveolus. The
only clinical indication of such events may be some loosening or sensitivity to
percussion (Figure 1), and the incidence of pulp necrosis and root resorption
processes are reported to be less than 5%.
One of the most dramatic
(and least frequent) luxation injuries is the total luxation of a tooth
following a traumatic injury (Figures 2-3-4-5). Exarticulation of teeth
generally involves maxillary central incisors in primary and permanent
dentition.8 Although reimplantation of avulsed permanent teeth is a
widely accepted therapeutic measure, the long-term prognosis remains
controversial, as many factors have been claimed to affect their success rate.9-11
The trauma of reimplantation can elicit
extensive pulpal damage, which is healed by various pulpodentinal reactions.
Microangiographic studies have demonstrated initial revascularization 4 days
following reimplantation. This extends to half of the pulp cavity after 10 days
and to the entire pulp cavity 30 days thereafter, primarily from the migration of
new blood vessels.12,13 Since reparative dentin is already
noticeable after 2 weeks in the apical third of the tooth, it has been
hypothesized that odontoblasts can survive the reimplantation procedure.14
An open root apex and a narrow pulp cavity appear to create favorable
conditions for the healing processes; the pulp of immature teeth recovers
vitality, but revascularization rarely occurs if root formation is completed.15
Regeneration of nerve
fibers is generally not observed prior to 1 month posttrauma and neither their
number nor their diameter reaches normal levels.16 Pulpal healing is
obviously essential for the endodontic prognosis of a reimplanted tooth, as
well as for the periodontal healing. With assistance of the coagulum present
following reimplantation or transplantation and reorganized by young connective
tissue, reattachment at the cementoenamel junction is possible at 1 week and
healing is completed after 2 weeks.
Root resorption and pulp
diseases are the most frequent complications in reimplanted teeth.17-19
Teeth subjected to either extended extraoral storage or unsuitable storage
media prior to reimplantation are more prone to develop severe root resorption.
Experimental studies on cell cultures have shown that dry storage of 60 minutes
can cause periodontal membrane (PDM) necrosis.20 Replanting teeth
with necrotic PDM will result in extensive root resorption, whereas preventing
PDM cells from drying during the extra-alveolar period promotes PDM healing
similar to that of an immediately reimplanted tooth.20
According to previous
findings, revascularization in mature teeth following reimplantation does not
occur, whereas in immature teeth occurrence of revascularization is low,
irrespective of the stage of root development, duration of extra-alveolar
period, or storage conditions.21,22 As a high incidence of pulp
necrosis is frequently reported in mature teeth -- even if pathways for pulpal
infection after reimplantation have not been fully clarified -- awaiting pulp
revascularization may predispose the tooth for failure.22 While the
literature suggests that endodontic treatment could be postponed in reimplanted
immature teeth,23 it should be instituted 2 to 3 weeks following
reimplantation in teeth with complete root development to prevent contamination
from nonvital pulp in the surrounding tissues.11
contamination appears to be the critical factor of pulp revascularization and
PDM healing processes, various methods of control (eg, topical or general
treatment with antibiotics) and use of artificial storage media have been
advocated. To date, no treatment has proven effective in controlling such
procedures, which suggests that only limited conclusions can be drawn from
experimental findings to increase the success rate of reimplantation.21
(Continued from page 1 )
Extrusion, and Lateral Luxation
While a general agreement exists concerning the
treatment procedures (ie, repositioning and splinting) of luxation injuries,
there is a large debate regarding the length of immobilization and the timing
of interceptive treatments in follow-up periods. Acute treatment of luxation
injuries varies from no treatment to repositioning and fixation for varying
periods. Numerous investigations have been undertaken to disclose if splinting
teeth may aid periodontal and pulpal healing. In an animal experiment, normal
masticatory stimulation appeared to eliminate small resorption areas.24
In the same manner, it has been demonstrated that PDL recovered 70% of its
original strength 14 days following extraction and reimplantation.25
As clinical healing of the periodontium occurs within 7 days by reattaching to
the new junctional epithelium, cases with minor supporting tissue injuries
(without alveolar bone support involvement) should not be splinted for more
than 1 to 2 weeks. Splinting has also been used to increase the extent of pulp
necrosis, due to less movement during fixation, which generally facilitates the
ingrowth of new vessels.9
Since they were first
used in maxillofacial fractures, the principles underlying tooth splinting have
changed dramatically. The incorporation of arch bars and acrylic caps has
influenced the demands of modern tooth fixation, and flexible arch wires or
acid-etched splints are required. Less rigid, they allow limited vertical
movement of the teeth and, therefore, reduce the risk of external root
These principles can be
applied in cases of extrusive and lateral luxation, where a fixation by a
flexible wire splint for 2 or 3 weeks is recommended, except when there is a
concomitant alveolar bone support fracture. In those situations -- particularly
in lateral luxation injuries -- an immobilization period of 4 to 6 weeks is
Extrusive luxations are
treated by a careful repositioning and splinting of the displaced tooth for a
period of 2 weeks (Figures 3-4-5-6-7-8). The healing process is generally
uneventful, although the incidence of pulp necrosis (up to 26%) and root
resorption phenomenon (possibly as high as 12%) requires regular radiological
and clinical controls at least during the first year following the traumatic
Lateral luxations are
often observed with other luxation injuries and -- when involving an extreme
displacement -- are accompanied by alveolar bone plate fracture (Figures 9-10-11-12-13-14). In these instances, the repositioning process is generally
forceful and requires a longer period of splinting (4 to 6 weeks minimum), as
it must cope with the rhythm of bone healing modalities. The rate of pulp
necrosis (up to 58%) and root resorption processes (up to 30%) is rather high,
although it is (as for other luxation injuries) highly correlated with the
stage of root development at the time of the trauma and with the intensity of
the impact during the luxation procedure. In both extrusive and lateral
luxations, the repositioning process must be carefully evaluated with proper
radiological controls that require occlusal views in lateral luxations to
assess the approximation between the alveolus and the root surface.
It must be stressed that
-- in cases of late consultation -- the repositioning procedure may be too
difficult to perform. The luxated tooth should then be allowed to realign
spontaneously or should be orthodontically moved at a subsequent stage,
following careful evaluation of pulpal and periodontal prognosis.
represent a significant challenge in dentoalveolar traumatology, as permanently
intruded teeth exhibit high rates of pulp necrosis and root resorptions (as
high as 85%). Immediate surgical repositioning of the intruded tooth may cause
permanent loss of a significant alveolar bone support and must be strongly
discouraged. It has been stated that intruded, partially immature teeth will
re-erupt spontaneously within 2 to 3 months following the injury (Figures 15-16-17a-17b). Bearing in mind that high pulpal infection rates can result in
inflammatory resorption processes and ultimately loss of the tooth in a 2- or 3-month
period, it is now recommended to proceed to the rapid orthodontic extrusion of
the tooth, which allows endodontic treatment if necessary. The clinical
situation occasionally requires surgical uncovering of the tooth, if it has been
completely intruded, and the entire orthodontic procedure can be performed in 4
to 6 weeks.
Clinical studies often
show that complications from traumatic injuries (eg, pulp necrosis or root
resorptions) generally develop during the year following the trauma. It may be
advisable -- contrary to the procedures used for intruded permanent teeth --
not to institute any orthodontic treatment during that observation period. The
relevant data in the scientific literature cannot confirm the increased
potential of root resorption during orthodontic treatment of luxated teeth.
Contradictory findings of different studies do not result in definitive
evidence of inflammatory or replacement root resorption exists, orthodontic
treatment should not be instituted. When inflammatory root resorption is
evident, the endodontic status should be controlled prior to introduction of
orthodontic therapy; in instances where replacement root resorption is evident,
the ankylosed tooth cannot respond to the application of orthodontic force. The
emergency treatment of dentoalveolar trauma is, therefore, critical, as it may
influence the prognosis of any multidisciplinary treatment initiated following
the observation period. The combined approach used in treatment of these
traumatic injuries involves different specialized fields of dentistry and
stresses the need for evaluation of the various treatment regimens. This will
ultimately ease the decision-making process in the difficult therapeutic
complications caused by traumatic loss or injury of anterior teeth.
*Senior Lecturer, Department of Orthodontics, University of Geneva,
†Former Head, Department of Orthodontics, University of Geneva,
‡Senior Lecturer, Department of Cariology,
Endodontics, and Pediatric Dentistry, University
of Geneva, Geneva, Switzerland.
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