Tasks for individual work during preparation to lesson.

4.1. List of basic terms, parameters, characteristic, which a student must master at preparation to lesson:

Term	Definition
10. Luxation of tooth.	This is dislocation of tooth with injury of periodont.
11. Fracture of tooth.	This is disorder of integrity of tooth’s tissues.
12. Fracture of alveola process.	This is disorder of integrity hard tissues of alveolar process of jaws.

7.2. Theoretical questions to lesson: 1.To give determination of concept «Tooth’s dislocation». 2. Classification of dislocations of tooth. 3. Clinical picture of tooth’s dislocation. 4. Methods of treatment of tooth’s dislocation. 5.Classification of tooth’s fractures. 6. Clinical picture of tooth’s fractures. 7. Methods of treatment of tooth’s fractures. 8. Clinic and diagnostics of alveolar process’ fractures. 9. Methods of treatment of alveolar process’ fracture.

7.3. Practical works (task) which are executed on lesson: 1. To select necessary tool for the inspection of patient with dislocation or fracture of tooth, with the fracture of alveolar process. 2. To select necessary tool for the replantation of tooth. 3. To produce smooth tire-staple. 4.To feel medical document of patient with dislocation or fracture of tooth, with the fracture of alveolar process.

5. TABLE OF CONTENTS OF THEME:

Dento-alveolar fractures

Dento-alveolar injuries are defined as those in which avulsion, subluxation or fracture of the teeth occurs in association with a fracture of the alveolus. Dento-alveolar injuries may occur as an isolated clinical entity or in conjunction with any other type of facial bone fracture. The detailed examination of the oral cavity usually follows the examination of the facial bones, unless it is obvious that the injuries are confined to the dento-alveolar component.

Andersson et al. (1984) reported a series of 795 jaw fractures presenting at dental clinics in an urban area. Injuries to the teeth occurred in 36 per cent of the cases. In the maxilla isolated fractures of the alveolar process, usually the incisor region, were the commonest injury comprising 40 per cent of the maxillary fractures. No nasal or zygomatic fractures were included in the series. The vast majority of dento-alveolar injuries are minor and occur in isolation, usually involving only a tooth and its periodontal membrane. The prevalence of traumatized permanent incisor teeth has been extensively documented (Hamilton et al., 1997) and is estimated to be as high as 40 per cent in the age range 8 to 15 (Andreasen and Ravn, 1972).

   Damage to teeth

The importance of dental trauma is that it frequently requires immediate treatment both to

relieve pain and often to preserve the dentition. Early treatment is imperative if there is exposure or near exposure of the pulp chamber or subluxation of an individual tooth or teeth. The dental injury will therefore take precedence over most other facial bone fractures.

Fracture of the crown of individual teeth may occur as a direct result of trauma or by forcible impaction against the opposing dentition. Anterior teeth are frequently damaged by direct impact, in which case there is often a ragged associated laceration of the upper lip or de-gloving of the alveolus. Posterior tooth injury may be caused by impaction of the two jaws together. When the lower teeth are forced against the occlusal surfaces of the upper, this may cause vertical splitting of one or more teeth. Meticulous dental examination is essential and any missing fragments of crown or missing fillings noted. Where missing teeth are noted it is important to be sure no retained roots are present. Fragments of teeth may become embedded in lip or tongue lacerations, or they may be swallowed, or rarely inhaled. Subluxation of teeth may cause derangement of the occlusion. Individual teeth may be missing and an empty tooth socket suggests that the tooth concerned has been knocked out. If a tooth or fragment of tooth cannot be accounted for, a chest X-ray should be ordered. This is particularly important if the patient was unconscious for any period after the injury as inhalation of a foreign body is much more likely in these circumstances.

Fractures of the roots of teeth may be present which are difficult to diagnose clinically. Excessively mobile teeth which do not appear to be subluxed are suspect and should be earmarked for later periapical radiographs. Occasionally molar and premolar teeth appear superficially normal but close inspection reveals either a vertical split or a horizontal fracture just below the gingival margin resulting from indirect trauma against the opposing dentition or violent impact by a small hard object such as a missile.

Electrical or thermal vitality tests at this stage of injury are unreliable and of little use in determining the eventual prognosis for the pulp. A blow of sufficient force to disrupt the alveolus will usually disturb the function of the nerve endings supplying individual teeth whose blood supply may nevertheless be intact.

Alveolar fractures

Alveolar fractures in the mandible are frequently associated with complete fractures of the tooth-bearing segment whereas in the maxilla they are more often isolated injuries. Unusually there may be no associated injury to the teeth. However, teeth within an alveolar fracture should be presumed to have been de­vitalized until evidence to the contrary emerges during the period of follow-up. Severe trauma in either jaw may result in gross comminution of the alveolus but more often the alveolar fracture consists of one or two distinct fragments containing teeth. During the initial examination it may be possible gently to reposition loose alveolar fragments, and the earlier this is achieved the better the prognosis for individual teeth.

In lower jaw fractures a complete alveolar fragment may be displaced into the soft tissues of the floor of the mouth and can on occasions be completely covered by mucosa. In the symphysis region it may be difficult to determine whether a loose alveolar fracture is part of a complete fracture of the mandible. An associated fracture through the lower border may be only a crack and less mobile than the alveolar segment.

Maxillary alveolar fractures occur most often in the incisor region in which case there may be obvious deformity of the alveolus and disturbance of the occlusion. This is not always the case as some of these fractures are impacted into the relatively soft bone of the maxilla and may be virtually immobile. Where dental exaination reveals damage to teeth or bruising of the alveolus, careful palpation is necessary to exclude any underlying alveolar fracture. Sometimes crepitation can be detected on palpation and a «cracked pot» note detected when the teeth within the impacted alveolar fracture are percussed.

A midline split of the palate converts a Le Fortt I fracture into two large dento-alveolar segments. A split palate may be suspected if there is a linear haematoma visible beneath the palatal mucosa. Movement of the fragments may be detected by firm digital separation of the two sides and confirmed by an occlusal radiograph. This is an important finding because the injury will have a fundamental bearing on the management of any other associated facial bone fractures.

Fracture of the maxillary tuberosity and fracture of the antral floor are recognized complications of upper molar extractions.

The term «dento-alveolar injurу» describes an injury which is limited to the teeth and supporting structures of the alveolus. As has been mentioned in the section on clinical findings such injuries can occur in isolation or as part of a more serious maxillofacial injury. Isolated dento-alveolar injuries usually follow relatively minor accidents such as falls, or collisions during sport or play. Cycling accidents and minor road traffic accidents are another common cause. Injury to the teeth can sometimes occur during epileptic seizures, and iatrogenic damage may take place during extraction of ankylosed teeth, endoscopy procedures or endotracheal intubation. In addition, the possibility of non-accidental injury should always be considered in younger children.

       The majority of patients presenting with isolated dento-alveolar injuries are children or adolescents and, as might be expected, boys are approximately three times more at risk than girls (Hunter et al., 1990; Andreasen and Andreasen, 1994). There is evidence that injury to the teeth is increasingly common despite the emphasis on the use of mouthguards in many sporting activities (Todd and Dodd, 1985; Dewhurst et al., 1998). A significant proportion of dento-alveolar injuries can be treated in the primary dental care setting under local analgesia, particularly where damage is limited to the teeth without alveolar fracture. Unfortunately surveys have found that an adequate level of knowledge and expertise in dental practice is often lacking, and even in the hospital setting the management of the dental injury is all too often less than ideal (Hamilton et al., 1997a,b).

 Dental hard tissue injury

(a) Crown infraction (crack of enamel or incomplete fracture)

(b) Crown fracture - enamel only

(c) Crown fracture - enamel + dentine

(d) Crown fracture - enamel + dentine +pulp

(e) Crown-root fracture (vertical fracture)

(f) Crown-root fracture (oblique fracture)

(g) Root fracture

Periodontal injury

(a) Concussion (no displacement of tooth but tender to percussion)

(b) Subluxation (loosening of tooth without displacement)

(c) Intrusion

(d) Extrusion

(e) Lateral luxation (loosening of tooth with displacement)

(f) Avulsion

Alveolar bone injury

(a) Intrusion of tooth with comminution of socket

(b) Fracture of single wall of socket or alveolus

(c) Fracture of both walls of socket of alveolus

(d) Fracture of mandible or maxilla involving the alveolus and/or tooth socket

Glngival injury

(a) Contusion

(b) Abrasion

(c) Laceration

Combinations of the above

A comprehensive classification of dento-alveolar injuries and full details of the management of damaged teeth are outside the scope of this book. Specialist texts on the subject should be consulted for further information (Andreasen and Andreasen, 1994; Roberts and Longhurst, 1996).

The pattern and complexity of a dento-alveolar injury depend on a number of factors. These include the site and energy of impact, the strength of the teeth, the resilience of the periodontal structures and the elasticity of the alveolar bone. The latter two factors in particular are also related to the age of the patient. Single or multiple teeth can be damaged individually, or a complete segment of alveolar bone can be fractured with relatively little damage to the group of teeth it supports.

Clinical assessment

An important point to reiterate is that urgent treatment is necessary if a tooth is to be saved following partial or complete avulsion. Similarly, any obvious or suspected exposure of the dental pulp will require early treatment for relief of pain and the best prognosis. Dento-alveolar injuries are among the very few fractures of the facial skeleton where immediate treatment is important. Not only does delay affect the ultimate prognosis of individual teeth, it may also prolong the patient's pain and discomfort after injury. Whereas simple jaw fractures are rarely very painful, injuries to vital teeth can cause severe pain and alveolar fractures may often result in painful interference with the occlusion.

When a dento-alveolar fracture occurs in isolation the injury is easily recognized and effective treatment is usually offered. However, when damage to individual teeth is part of a more extensive facial injury the importance of early intervention may be forgotten, even when it could easily be accomplished under local analgesia. The treatment of dento-alveolar injuries should have the same priority as the treatment of facial lacerations. Simple measures such as repositioning of displaced teeth and protection of the pulp are sometimes overlooked in the initial management of a complex facial injury. In an unconscious multiply injured patient requiring endotracheal intubation the dental injuries may seem a trivial problem, and even go unrecognized, but stabilization of any loose teeth or alveolar segments will minimize difficulties in positioning the tube and prevent further dental damage. Similarly, covering or extirpating the exposed dental pulp will reduce the painful stimuli which can contribute to rest lessness in the unconscious patient.

A thorough clinical assessment of the dentition requires a good inspection light, adequate retraction of the lips and cheeks, a fine-tipped sucker, the use of a dental mirror and probe, and a co-operative patient. These conditions are normally achievable with a conscious adult but in the case of a distressed young child full assessment may have to await the administration of a general anaesthetic. The most difficult injuries to diagnose clinically are stable root fractures and vertical crack fractures of the crowns of posterior teeth. In this situation the examination should include percussion of the teeth, careful probing of the crown and asking the patient to bite gently on a wooden spatula.

The radiographic examination of dento-alveolar injuries must include occlusal or periapical dental radiographs. With the advent of panoral tomography these views are less used than they should be in the diagnosis of maxillofacial trauma but full assessment of injuries to the teeth is impossible without them.

Treatment

Several factors have to be taken into consideration in the treatment of dento-alveolar injuries. The relative importance of preserving damaged teeth will vary according to the complexity of the maxillofacial injury, the age of the patient, the general dental condition including crowding, the site of the dento-alveolar injury and the wishes of the patient. The prognosis of traumatized teeth and the healing of alveolar fractures are generally better in younger patients. Open root apices, intact gingival tissues, absence of root fractures and good periodontal bone support are all clinical conditions which are indicative of a good outcome.

In the deciduous dentition the pattern of injury differs from adolescents and adults because the elasticity and thinness of the alveolar bone usually protects against fracture of the tooth. Segmental fractures of the alveolus are extremely rare for the same reason. The more complex dento-alveolar injuries normally affect the permanent dentition and in planning treatment it is convenient to consider each component in turn. These range from a small chip of a cusp or incisal edge to multiple broken and displaced teeth with an associated fracture of the supporting alveolus.