Traumatic Injuries to the Teeth:


CLASSIFICATION
Dental injuries have been classified according to a variety of factors, such as etiology, anatomy, pathology and therapeutic considerations



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1. Classification by Ellis and Davey (1960) (Fig. 1)
• This classification is based on numeric system. Though it is simple, is only applicable to the permanent dentition.
• All the primary teeth have been grouped but detailed description has not been given (Grouped as class 9).
• It is one of the most widely accepted methods of classification.
Class I - Simple fracture of the crown involving little (or) no dentin.
Class II - Extensive fracture of the crown involving considerable dentin, but not the dental pulp.
Class III - Extensive fracture of the crown involving considerable dentin and exposing the dental pulp.
Class IV - The traumatized teeth that become nonvital with (or) without loss of crown structure.
Class V - Teeth lost as a result of trauma.
Class VI - Fracture of the root with or without a loss of crown structure.
Class VII - Displacement of a tooth without fracture of crown (or) root.
Class VIII - Fracture of crown en masse and its replacement.
  Class IX - Injuries to primary dentition



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Fig. 1: Classification of Dental injuries by ELLIS and DAVEY (1960)
  WHO Classification of Traumatic Injuries


The World Health Organization (WHO) described a classification in 1978 with a code number which corresponds to the international classification of diseases:
1. 873. 60 Enamel fracture.
2. 873.61 Crown fracture involving enamel and dentine without pulp exposure.
3. 873.62 Crown fracture with pulp exposure.
4. 873.63 Root fracture.
5. 873.64 Crown root fracture.
6. 873.66 Luxation.
7. 873.67 Intrusion or extrusion.
8. 873.68 Avulsion.
9. 873.69 Other injuries such as soft tissue and laceration.
Andreasen's Modification
873-64 Uncomplicated crown root fracture without pulp exposure
1. 873-64 Complicated crown root fracture with pulp exposure
2. 873-66 Concussion, injury to the supporting structure without displacement with reaction to percussion.
3. 873-66 Subluxation, injury to the supporting structures without displacement but abnormal loosening.
4. 873.66 Lateral luxation displacement other than axial direction with the fracture of alveolar socket.
Recent Classification By WHO (1992) (Fig. 2)
The code number is according to the international classification of diseases (1992). The present classification is based on a system adopted by the world health organization in its application of international classification of diseases to dentistry and stomatology. The following classification includes injuries to the teeth, supporting structures, gingiva and oral mucosa and is based on anatomical, therapeutic and prognostic considerations. This can be applied to both the permanent and the primary dentitions.
INJURIES TO THE HARD DENTAL TISSUES AND THE PULP
• Enamel Infraction
• (502.50) An incomplete fracture (crack) of enamel without the loss of tooth substance (N502.50).
• Enamel fracture (Uncomplicated crown fracture) (502.50): A fracture with loss of tooth substance confined to the enamel (N502.50).
• Enamel-dentin fracture (Uncomplicated crown fracture) (N502.51): A fracture with loss of tooth substance confined to enamel and dentin, but not involving the pulp.
• Complicated crown fracture: (N502.52): A fracture involving enamel and dentin, and exposing the pulp.
• Uncomplicated crown root fracture (N 502.54): A Fracture involving enamel, dentin and cementum, but not exposing the pulp.
• Complicated crown root fracture (N 502.54): A Fracture involving enamel, dentin and cementum and exposing the pulp.
• Root fracture (N 502.53): A Fracture involving dentin, cementum and the pulp.


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Fig. 2: WHO classification

INJURIES TO THE PERIODONTAL TISSUES
Concussion (N 503.20) (Fig. 3): An injury to the tooth supporting structures without abnormal loosening (or) displacement of the tooth, but with marked reaction to percussion.
Subluxation (Loosening) (N 503.20) (Fig..4): An injury to the tooth-supporting structures with abnormal loosening, but without displacement of the tooth. Extrusive Luxation (Peripheral dislocation, Partial avulsion) - (N 503.20) Partial displacement of the tooth out of its socket.




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Fig. 3: Concussion                         Fig. 5: Intrusive luxation


Lateral Luxation (N 503.20): Displacement of the tooth in a direction other than axially. This is accompanied by comminution (or) fracture of the alveolar socket. Intrusive Luxation (Central dislocation) (Fig. 5): (N 503.21) Displacement of the tooth into the alveolar bone. This injury is accompanied by comminution (or) fracture of the alveolar socket. Avulsion Injuries (N 503.22) (Fig. 6): Complete displacement of the tooth out of its socket.



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INJURIES TO GINGIVA (OR) ORAL MUCOSA
• Laceration of gingiva or oral mucosa (S01.50): A shallow (or) deep wound in the mucosa resulting from a tear and usually produced by a sharp object.
• Contusion of gingiva or oral mucosa (S00.50): A bruise usually produced by impact with a blunt object and not accompanied by a break in mucosa, usually causing submucosal hemorrhage.
• Abrasion of gingiva or oral mucosa (S00.50): A superficial wound produced by rubbing (or) scraping of the mucosa leaving a raw, bleeding surface.
MODIFICATION OF ELLIS CLASSIFICATION BY MCDONALD (1983)
This classification is a simpler and clearer version of the Ellis classification based on the anatomic and morphological aspect of the anterior tooth.
Class 1 : Simple fracture of the crown involving little or no dentin.
Class 2 : Extensive fracture of the crown involving considerable dentin, but not the dental pulp.
Class 3 : Extensive fracture of the crown with an exposure of the dental pulp.
Class 4 : Loss of the entire crown.
CLASSIFICATION BY HARGREAVES AND CRAIG (1970)
It is a modification of Ellis and Davey's classification but emphasis has been made to the involvement of
periodontium along with the coronal and radicular fractures.
Class I - No fracture (or) fracture of enamel only, with (or) without loosening (or) displacement of tooth.
Class II - Fracture of crown involving both enamel and dentin without exposure of pulp with (or) without loosening (or) displacement of tooth.
Class III - Fracture of crown exposing pulp with (or) without loosening (or) displacement of tooth.
Class IV - Fracture of root with or without coronal fracture with/or without loosening or displacement of tooth.
Class V - Total displacement of tooth.
EPIDEMIOLOGY
SEX and AGE Distribution
Boys appear to sustain injuries to the permanent dentition almost twice as often as girls. This is related to their more active participation in games and sports.
• In the permanant dentition, a marked increase in the incidence of traumatic injuries is seen for boys aged (8-10) years, while the incidence is rather stable for girls.
• When injuries affecting primary and permanent teeth are compared,
a. Trauma to the primary dentition is usually confined to the supporting structures, i.e. luxation and exarticulation.
b. The largest proportion of injuries affecting the permanent dentition are crown fractures.
SEASONAL VARIATIONS
Several studies have shown that the frequency of dental injuries increases during the winter months.
PREDISPOSING FACTORS
a. Increased overjet with protrusion of upper incisors and insufficient lip closure.
b. Dentinogenesis imperfecta
c. Battered child syndrome.
d. Mental distress and history of previous injuries were shown to increase the risk for dental injuries.
e. Overweight and high alcohol consumption were associated with a high life time prevalence of tooth trauma.
ETIOLOGY
The frequency increases as the child begins to waand tries to run, due to lack of experience and coordination. The incidence of dental injuries reaches its peak just before school age and consists mainly of injuries due to falls and collisions.
A. Automobile injuries:
i. Multiple dental injuries.
ii. Injuries to the supporting bone.
iii. Soft tissue injuries to the lower lip and chin.
B. Falls and collisions:
• When the child reaches school age, accidents in the school playground are very common.
• They are characterized by a high frequency of
crown fractures.
C. Bicycle injuries:
• They result in severe trauma to both the hard and soft tissues due to the high velocity at the time of impact.
• Patients sustaining this type of trauma
frequently experience:
i. Multiple crown fracture.
ii. Injuries to the upper lip and chin.
D. Sports:
• Injuries during the teens are often due to contact sports such as:
i. Ice hockey.
ii. Soccer.
iii. Basket ball.
iv. American football.
v. Rugby
vi. Wrestling.
E. Assaults:
• Injuries from fights are prominent in older age groups and are closely related to alcohol abuse.
• This type of trauma usually results in a particular injury pattern characterized by luxation and exarticulation of teeth as well as fractures of roots and/or supporting bone.
• In most of the cases men under the influence of alcohol abuse their wives and children.
F. Torture:
• A disgraceful and apparently increasing type of injury is represented by trauma to the oral and facial regions of tortured prisoners.
• The most common type of torture was beating, which resulted in loosening, avulsion or fracture of teeth and soft tissue laceration.
• In some cases, deliberate tooth fractures with forceps were also seen.
• In some cases, electrical torture was described in which electrodes were attached to teeth, lips, tongue and soft tissue over the TMJ, which resulted in very forceful occlusion due to muscle spam.
• This resulted in loosening and fracture of teeth and severe pain in the muscles and TMJ.
G. Mental Retardation:
• Incidence of dental injuries among mentally retarded patients is related to:
i. Lack of motor coordination.
ii. Crowded conditions in institutions.
iii. Concomitant epilepsy.
H. Epilepsy:
• High frequency of dental injuries in epileptic patients could be directly related to falls during epileptic seizures.
I. Related Injuries:
• Many drug addicts suffer from crown fractures of molars and premolars, resulting from violent tooth clenching 3 to 4 hours after drug intake.
• Fractures are confined to buccal and lingual cusps.
MECHANISMS OF DENTAL INJURIES
• The exact mechanisms of dental injuries are mostly unknown and are without any experimental evidence. Injuries can be the result of either direct or indirect trauma.
• Direct trauma occurs when the tooth itself is struck e.g. against playground equipment, a table or chair or any other stationary object.
• Indirect trauma is seen when the lower dental arch is forcefully closed against the upper, as by a blow to the chin in a fight (or) a fall.
• While direct trauma usually results in injuries to the anterior region, indirect trauma usually favors crown-root fractures in the premolar and molar regions, as well as the possibility of jaw fractures in the condylar regions and symphysis.
• The following factors characterize the impact and
determine the extent of injury.
1. Energy of Impact
This factor includes both mass and velocity. Examples:
a. A force of high velocity and low mass (Gunshot).
b. High mass and minimal velocity (striking the tooth against the ground).
Various studies have shown that:
i. Low velocity blows cause the greatest damage to the supporting structures and tooth fractures are less pronounced.
ii. In high velocity impacts the resulting crown fractures are usually not associated with damage to the supporting structures.
2. Resilience of the Impacting Object
If a tooth is struck with a resilient or cushioned object, such as an elbow during play or if the lip absorbs and distributes the impact, the chance of crown fracture is reduced while the risk of luxation and alveolar fracture is increased.
3. Shape of the Impacting Object
• Impact with a sharp object favors clean crown fractures with a minimum of displacement of the tooth, as the energy is spread rapidly over a limited area.
• Impact with a blunt object increases the area of resistance to the force in the crown region and allows the impact to be transmited to the apical region, causing luxation or root fracture.
4. Direction of the Impacting Force
• Frontal impacts to anterior teeth generate forces which tend to displace the coronal portion orally. A different situation arises if the bone and the periodontal ligament resist displacement. Horizontal fracture may occur when the root is firmly locked in its socket.
5. Enamel Prisms
• The orientation of the enamel prisms determines the course of fracture line in enamel. The direction of the fracture in dentin is primarily perpendicular to the dentinal tubules. Experimental evidences have shown that enamel is weakest parallel to the enamel rods and dentin is most easily fractured perpendicularly to the dentinal tubules.
CROWN FRACTURES
The most common causes of crown fractures are falls, automobile accidents and athletic activities.
Classification Crown fractures are classified according to the following traditional categories:
1. Infraction: An incomplete fracture of the tooth without actual loss of tooth substance.
2. Uncomplicated crown fracture: A fracture with loss of tooth substance confined to enamel.
3. Enamel-dentin fracture: A fracture with loss of tooth substance confined to enamel and dentin, but not involving the pulp.
4. Complicated crown fracture: A fracture involving enamel, dentin and pulp.
ENAMEL FRACTURES (FIG. 7)
These injuries involve the loss of the portion of coronal tooth enamel subsequent to a force directed perpendicularly or obliquely to the incisal edge of the traumatized tooth.
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BIOLOGIC CONSEQUENCES
If the fracture involves the enamel only th consequences are minimal and any complications may be because of a concomitant injury to the attachment apparatus.
DIAGNOSIS AND CLINICAL PRESENTATION
Enamel fracture includes superficial rough edge that may cause irritation to the tongue or lips. Sensitivity to air or liquids is not a complaint.
Treatment
Enamel fractures: An isolated fracture of the enamel does not usually pose a threat to the health of dental pulp; rather it is an annoyance to the tongue, lips or buccal mucosa.
1. Immediate treatment of crown fractures confined to enamel can be limited to smoothing of sharp enamel edges. This includes recontouring the injured tooth, adjacent teeth and / or the opposing teeth. This treatment is appropriate to eliminate the sharp enamel edges associated with minor injuries and prevents the laceration of tongue, lips or oral mucosa.
2. When the shape and extent of the fracture precludes recontouring a restoration is necessary. This includes restoration of the missing tooth structure with composite resin after acid conditioning of the enamel surface. It is essential that the crowns anatomy and occlusion be restored immediately in order to prevent labial protrusion of the fractured tooth, drifting or tilting of adjacent teeth into the fracture site or over eruption of opposing incisors.
DENTIN FRACTURES
These injuries involve the loss of tooth substance confined to enamel and dentin but not involving the pulp.
DIAGNOSIS AND CLINICAL PRESENTATION
An enamel and dentin fracture also includes a rough edge on the tooth, but sensitivity to air and hot and cold liquids and pain on mastication may be a chief complaint. The intensity of these symptoms is related directly to the amount of exposed dentin and to the maturity of tooth.
Treatment
The objective in treating a tooth with a fractured crown without pulpal exposure is three fold:
1. Elimination of discomfort.
2. Preservation of vital pulp.
3. Restoration of fractured crown (Figs 8 and 9) On initial presentation of a patient for treatment of a crown fracture including enamel and dentin, the tooth should be tested with: a) Electric pulp tester, b) Ice, c) Ethyl chloride spray, d) Periapical radiograph.
Treatment is done in two stages:
1. Temporary restoration: After the fracture, as soon as possible the exposed dentin should be protected by sedative cement such as zinc oxide eugenol held in a crown form. Vitality testing can be conducted with the ethyl chloride spray or ice around the crown margins. The patient is recalled after one month for vitality testing. If the response continues to be within the normal range a permanent restoration may be constructed for the tooth.
2. Permanent restoration (Fig. 8):

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Fig. 8: Enamel and dentin fractures              Fig. 9: Reattachment
The recommended restoration for uncomplicated crown fractured teeth includes the use of adhesive resin and composite resin systems. The recommended procedure for restoring the fractured segment of an uncomplicated crown fracture includes the following steps:
a. Clinical assessment/diagnosis, selection of composite shade for restoration.
b. Cleaning of the fractured tooth, gentle irrigation with an air water syringe.
c. Placing of a glass ionomer liner over the exposed dentin
d. Etching the enamel with 37 percent phosphoric acid, water rinsing and drying.
e. Applying the denting bonding agent.
f. Restoring the tooth to its original contours with composite resin and finishing the margins with a carbide finishing bur and polish as needed.
g. Validating occlusion.
Treatment (Figs 11 to 13)
Treatment planning is influenced by tooth maturity and extent of fracture. Every effort must be made to preserve pulps in immature teeth.
Choice of treatment depends on the:
1. Stage of development of the tooth.
2. Time between the accident and the treatment.
3. Concomitant periodontal injury.
1. Stage of development of the tooth: Root canal treatment
on a tooth with a blunderbuss canal is time consuming and difficult. Necrosis of the pulp of an immature tooth leaves the tooth with thin dentinal walls that are susceptible to fracture during and after the apexfication procedure. Therefore, every effort must be made to keep the tooth vital at least until the apex and cervical root have completed their development. In an immature tooth vital pulp therapy should always be attempted, if at all feasible, because of the tremendous advantages of maintaining the vital pulp.
2. Time between the accident and treatment: For 24 hours after traumatic injury the initial reaction of the pulp is proliferative with no more than 2 mm depth of pulpal inflammation. After 24 hours, chances of direct bacterial contamination from the pulpn increase with resultant progression of the zone of inflammation in an apical direction. Thus as time progresses, chances of successfully maintaining healthy pulp decreases.
3. Concomitant attachment damage: A periodontal injury will compromise the nutritional supply of
the pulp. This fact is particularly important in mature tooth where the chance of pulp survival is not as good as for immature teeth.
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EXTRUSIVE LUXATION (FIG. 14)
Partial displacement of the tooth out of its socket

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Treatment (Fig. 15)
Push the tooth back to original position and check occlusion. Use splinting up to three weeks.
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INTRUSIVE LUXATION (CENTRAL DISLOCATION) (FIG. 16)

Displacement of the tooth into the alveolar bone. This injury is accompanied by comminution (or) fracture of the alveolar socket.
Treatment (Fig. 17)
There are two types of treatment:
1. Orthodontic extrusion.
2. Surgical movement of the tooth to normal occlusion stabilized with splint up to two three weeks (Fig. 18)


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AVULSION
Definition
It is defined as complete displacement of the tooth from the alveolus.It is usually the result of trauma to an anterior tooth and is both a dental and an emotional problem. Prognosis depends on the amount of time the tooth is out of the socket.
Management (Fig. 19)
Success depends on speed with which the tooth is replaced.


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Preparation of Root
• If extraoral time is less than 20 mins, periodonta healing is excellent.
• Root is rinsed of debris with water or saline and replanted gently. Prognosis depends on whether root is open or closed.
• If extraoral time is more than 60 mins, periodontal cells would have lost their vitality. In this case the tooth is soaked in citric acid for 5 mins and in
2 percent Stannous fluoride for 5 mins to remove remaining periodontal cells and is then replanted.
• If tooth is dry for more than 60 mins, endodontic treatment is performed extraorally. The socket is
lightly aspirated if blood clot is present.
Splinting: To be done for 7-10 days:
• The splint should allow physiologic tooth movement during healing to prevent ankylosis .
• After splinting, traumatic occlusion is avoided.
• After 7-10 days splint is removed, since one week is sufficient to create periodontal support.
• In case of alveolar fracture, splint is placed for 4-8 weeks.
• Management of soft tissues is done.
ROOT FRACTURE
Healing or Repair After Root Fracture
• Healing events following root fracture are initiated at the site of pulpal and periodontal ligament involvement and this creates two types of wound healing response.
• These processes apparently occur independently of each other and close the injury site with either pulpal or periodontally derived tissue.
• On the pulpal side of the fracture, two healing events might occur, depending upon the integrity of the pulp at the level of fracture.
A. If the pulp is intact at the fracture site, it will react in a manner analogous to a coronal pulp exposure under optimal conditions (i.e. with an intact vascular supply and absence of infection).
• Odontoblast progenitor cells will be recruited and create a hard tissue bridge which will unite the apical and coronal fragments after 2-3 months.
• This bridge forms the initial callus which will stabilize the fracture.
• Callus formation is followed by deposition of cementum derived by ingrowth of tissue from the periodontal ligament at the fracture line, first centrally and gradually obliterating the fracture site.
B. In the event that the pulp is severed or severely stretched at the level of the fracture, a revascularization process in the coronal aspect of the pulp is initiated.
• In the absence of bacteria, this process will result in obliteration of the coronal pulp canal.
• While the revascularization process is underway, periodontally derived cells can dominate root fracture healing, resulting in union of the coronal and apical root fragments by interposition of connective tissue.
• If bacteria gain access–usually to the coronal pulp–an infected pulp necrosis results, with accumulation of inflamed granulation tissue between the two root fragments.
• During the initial stages of wound healing, traumatized pulpal and hard dental tissues can stimulate an inflammatory response and thereby trigger the release of a series of osteoclast-activating factors.
• Thus, root resorption processes beginning either at the periphery of the fracture line adjacent to the periodontal ligament or centrally at the border of the root canal are observed in 60 percent of root fractured incisors.
• Radiographic and histological observations in human subjects have revealed that the final outcome after root fracture can be divided into the events listed below.
A. HEALING WITH CALCIFIED TISSUE
• This type of healing is dependent upon an intact pulp and is seen in cases with little or no dislocation (i.e. concussion or subluxation) of the coronal fragment and in teeth with immature root formation. A uniting callus of hard tissue has been demonstrated histologically in a number of cases. Dentin, osteodentin or cementums have been found in the repair site.
• In most cases, the innermost layer of repair seems to be dentin, while the more peripheral part of the fracture is incompletely repaired with cementum. Most often, cementum will not completely bridge the gap between the fracture surfaces, but is interspersed with connective tissue originating from the periodontal ligament. Occasionally, a slight widening of the root canal close to the fracture site is seen (i.e. internal surface resorption) followed by hard tissue formation. Partial pulp canal obliteration confined to the apical fragment is a frequent finding.
• Clinical examination of teeth within this healing group reveals normal mobility, as compared with non-injured adjacent teeth; moreover, there is normal reaction to percussion and normal or slightly decreased response to pulpal sensitivity testing.
C. INTERPOSITION OF BONE AND CONNECTIVE TISSUE
• Histologically teeth in this healing group demonstrate interposition of a bony bridge and connective tissue between the apical and coronal fragments with a normal periodontal ligament surrounding both fragments.
• In some cases, bone can be seen extending into the root canals.
• This mode of healing is apparently a result of trauma prior to complete growth of the alveolar process; thus the coronal fragment continues to erupt, while the apical fragment remains stationary in the jaw.
• Radiographically, a bone bridge is seen separating the fragments, with a periodontal space around both fragments.
• Total pulp canal obliteration of the root canals in both fragments is a common finding.
• Clinically the teeth are firm and react normally to pulp tests.
D. INTERPOSITION OF GRANULATION TISSUE
• Histologic examination of teeth in this group reveals inflamed granulation tissue between the fragments.
• The coronal portion of the pulp is necrotic while the apical fragment usually contains vital pulp tissue.
• The necrotic and infected pulp tissue is responsible for the inflammatory changes along the fracture line.
• In some cases, communication between the fracture line and the gingival crevice is the source of inflammation.
• Radiographically, widening of the fracture line and rarefaction of the alveolar bone corresponding to the fracture line are typical findings.

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