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Reaction of permanent tooth bud to injury

الكلية كلية طب الاسنان     القسم التقويم والاطفال وطب الاسنان الوقائي     المرحلة 5
أستاذ المادة حسن فليح فرحان السلطاني       6/5/2011 3:59:24 AM

Lec. 13                                       Pediatric dentistry                            Dr. hasssan Wateefi

 

Reaction of permanent tooth bud to injury
The close anatomic relationship between the apices of primary teeth and their developing permanent successors explains why injuries to primary teeth may involve the permanent dentition. Some injuries to the face and jaws may not appear to have caused any dental injuries initially, but the problem maybe noticed several months or years later.

1- Hypocacification and Hypoplasia
Hypocacification: Small areas that showed destruction of the ameloblasts and a pitted area where a thin enamel layer had been laid down before the injury.
Hypoplasia: Small destruction of the ameloblasts before any enamel had been laid down, resulting in hypoplasia that clinically appeared as deep pitting or gross malformations of the crown. These small, pigmented hypoplastic areas have been referred to as Turner tooth. Small hypoplastic defects may be restored by the resin-bonding technique.

2- Reparative dentine production
In cases in which the injury to the developing permanent tooth is severe enough to remove the thin covering of developing enamel or cause destruction of the ameloblasts,
the subjacent odontoblasts have been observed to produce a reparative type of dentin. The irregular dentin bridges the gap where there is no enamel covering to aid in protecting the pulp from further injury.
3- Dilaceration
The condition referred to as dilacerations occasionally occurs after the intrusion or displacement of an anterior primary tooth. The developed portion of the tooth is twisted or bent on itself, and in this new position growth of the tooth progresses. Cases have been observed in which the crown of a permanent tooth or a portion of it develops at an acute angle to the remainder to the tooth.

Clinical Evaluation of Dental Trauma:
       The following dental and medical history lines are necessary for good evaluation:

1- Medical History:
1. Take a complete medical history.
2. Assess the need for antibiotic prophylaxis.
3. Determine if the child is immunocompromised or has congenital heart disease and bleeding disorder. Bleeding disorders and drug allergies may require alternative approaches.
4.  Record any current medications.
5.  Obtain a history of any prior surgeries.
6. Determine if the child’s tetanus immunization is up-to-date.
7. Determine if the child lost consciousness due to the injury.

2- Dental History:
The clinician should determine how, when, and where the injury occurred.
“How” is important because it provides information on the severity of the injury. “When” is important, because the prognosis for the injured tooth worsen with every minute of delay in treatment. If the fracture occur before 1year, there is a high probability that the tooth is non vital.
"Where” is important, because it may determine whether or not tetanus prophylaxis is warranted.
"Pain" is important in determine the extent of injury.
• Pain caused by thermal change indicates significant pulp inflammation.
• Pain during bringing the teeth in occlusion indicate the tooth has been displaced such pain indicate injury to P.D.L. and supporting tissue.
3- Physical Examination:
 Important information to be gathered for each patient includes:
1. Vital signs.
2.  Review of all systems, head and neck examination, and accident information.
3.  It is important to rule out head injury. Headache, vomiting, amnesia and brain damage must be excluded and referral to a hospital for further investigation organized.
4.  An evaluation of pupil size and reaction to light may establish the presence of head injury.
4- Extra oral Examination:
Examinations must start extraorally for lacerations, hemorrhage and swelling of the extra oral structures. If a laceration is present in the upper or lower lip, the area must be inspected for foreign bodies such as tooth fragments. Any foreign bodies must be deprived from the soft tissue. The location and size of all extra oral and intraoral injuries must be recorded. Palpate the mandible, zygoma, tempromandibular joint and mastoid region. Ensure that no mandibular or maxillary fractures are present.

5- Intra oral Examination:
1- All intra oral clots and debris must be removed prior to examining the oral soft and hard tissue. This can be done with a piece of cotton moisted with normal saline or hydrogen peroxide. 
2- Palpate the alveolus to detect any fractures.
3- Have the patient clench the teeth so that the dental occlusion can be evaluated.
4- Each tooth should be examined for the presence of fracture and its type, abnormalities of occlusion, tooth displacement, fractured crowns or cracks in the enamel.
5- Degree of mobility, reaction to percussion and thermal or electrical sensitivity tests and radiographic images are all important diagnostic measures for traumatized tooth.
6- Color of the tooth: severely traumatized teeth often appear darker and reddish indicate pulp hyperemia which may end with pulp necrosis.
7- Intraoral structures for swelling of the oral mucosa and gingiva,
8- The labial mucosa, maxillary frenum, gingival tissues, and tongue should be examined for bruising or lacerations. All intraoral lacerations must be cleaned and explored, looking for any foreign bodies.
In children the use of EPT at the time of trauma is controversial because of:
• The tooth still in a state of shock so reexamine the tooth in the next visit after 6 weeks, if the child doesn t give any response mean the tooth is died.
•   It needs cooperation and relaxed child, so anxiety will give a false response.

6- Radiographical Examination: It used in order to:
• Approximate the size of the pulp chamber.
• The stage of apical development which indicates type of treatment.
• Root fracture.
• Alveolar bone fracture.
• P.D. condition.
• For comparison with record in the future
For evaluating injuries to the maxillary or mandibular teeth, an occlusal radiograph is the film of choice for detection of root fracture when used intraoraly and foreign bodies like tooth fragment when used extra orally. If a root fracture is suspected, periapical radiographs at two different angles are required for a definite diagnosis. For intruded teeth, a lateral anterior radiograph provides additional useful information. If a tooth or fractured piece cannot be accounted for when there has been a history of loss of consciousness then a chest radiograph should be obtained to exclude its inhalation. A panoramic radiograph helps to evaluate suspected mandibular or condylar fractures.
7- Photographic Documentation:
The use of preoperative and postoperative photography is very useful for documentation purposes. All patients with traumatized teeth ultimately need follow-up with a dentist for complete diagnosis and long term care.

Emergency treatment of soft tissue injuries
Injury to the teeth of children is often accompanied by:
1. Open wounds of the oral tissues.
2. Abrasion of the facial tissues.
3. Puncture wounds.
Treatment includes:
1- Clean the wound with cotton and disinfectant. 
2- Minor soft tissue need suturing while sever injury may need hospitlazation.
2- The dentist must recognize the possibility of the development of tetanus after the injury and must carry out adequate first-aid measures. Primary immunization is usually a part of medical care during the first 2 years of life. However, primary immunization cannot be assumed but must be confirmed by examining the child s medical record.
An unimmunized child can be protected through passive immunization with tetanus antitoxin (tetanus immune globulin, or TIG).

Management of Injuries to Primary Dentition:
A few restorative procedures will be possible.
A primary incisor should always be removed if its maintenance will jeopardize the developing tooth bud. A traumatized primary tooth that is retained should be assessed regularly for clinical and radiographic signs of pulpal or periodontal complications.
1. Uncomplicated crown fracture require either smoothening the sharp edges or restore with an acid etch restoration.
2. Complicated crown fracture require extraction or pulp care, while in the majority of cases like, concussion, subluxation and luxation injuries, the decision is between extraction or mainte¬nance without performing extensive treatment.
3. Primary teeth that are displaced but not intruded should be repositioned by the dentist or parent as soon as possible after the accident to prevent interference with occlusion. Give the child soft diet, analgesic and antibiotic and observe at one week, one month radio graphically. The prognosis for severely loosened primary teeth is poor. Frequently the teeth remain mobile and undergo rapid root resorption. Teeth with complete root formation seemed to undergo resorption more frequently than those with incomplete root formation. However, when resorption did occur, it was more extensive and progressed more rapidly in teeth with incomplete root development. If the traumatized teeth are so loose that they are in a danger of being aspirated or if they interfere with normal occlusion, immediate referral to a dentist for extraction is required.  
4. Intrusion of primary teeth is common during 1st 3years of life during falls in which the tooth forcefully pushed into the alveolar bone and some time the entire clinical crown becomes buried in bone and soft tissues.     
Treatment:
• It is generally agreed that immediate attention should be given to soft tissue damage.
• Intruded primary teeth should be observed; with few exceptions, no attempt should be made to reposition them after the accident.
• Primary anterior teeth intruded as a result of a blow may often re erupt within 3 to 4 weeks after the injury.
•  Most injuries of this type occur at an age when it would be difficult to construct a splint or a retaining appliance to stabilize the repositioned teeth.
•  Normally the developing permanent incisor tooth buds lie lingual to the roots of the primary central incisors. Therefore, when an intrusive displacement occurs, the primary tooth usually remains labial to the developing permanent tooth.
•  If the intruded primary tooth is found to be in a lingual or encroaching relationship to the developing permanent tooth, it should be removed. Such a relationship may be confirmed from a lateral radiograph of the anterior segment.
6- Root fracture of primary teeth is relatively uncommon because the more pliable alveolar bone allows displacement of the tooth. When root fracture does occur, it should be treated in the same manner as was recommended for permanent teeth; however, the prognosis is less favorable.
 Intruded primary teeth may cause:
• Localized hypoplasia if it is mild.
• Dilacerations if it is severe
7-Replantation of exarticulation or avulsion of primary teeth is not recommended due to risk of damage to the permanent tooth bud.



المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .