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| IMC Wiki | Crown fractures

Crown fractures

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Crown injuries



Tooth 11 with chipped-off enamel and extrusion, Tooth 21 with enamel-dentine fracture
#pic#
  1. Crown infraction
    #pic#
  2. Unmplicated crown fracture/enamel-dentine fracture without pulp opening
    #pic#
  3. Complicated crown fracture/enamel-dentine fracture with pulp opening
    #pic#
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Crown infraction

In crown fractures with pulp exposure, it is always necessary to make a permanent filling - never a temporary.

Crown fractures
  Uncomplicated crown fractures Complicated crown fractures
Radiological assessment and findings
  • Take X-rays (orthoradial projection)
  • Determine the size of the pulp chamber and stage of root development
  • Perform sensitivity analysis
Same procedure as described for uncomplicated crown fractures
Treatment
  • Ask for the crown segment
  • Check soft tissue lacerations for the presence of tooth fragments or other foreign bodies
  • If available, reattach the crown segment using a bonding technique
  • Temporarily fill the dentin wound with glass ionomer cement or permanently fill with composite material
  • Calcium hydroxide should be used in the vicinity of the pulp
  • Smooth and fluoridate small enamel defects
  • Crown fractures in immature teeth: Direct pulp capping or partial pulpotomy
  • Seal to prevent bacterial invasion
  • Crown fractures in mature teeth:
    Treatment procedure same as that described for immature teeth or pulpotomy

Enamel-dentine fracture without pulp opening

Uncomplicated crown fractures
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Tooth reconstruction with a composite
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  • Minor enamel defects are levelled and fluoridated
  • The dentine wound should be treated
  • The tooth is reconstructed with a composite
  • or the crown fragment is fixated using adhesive techniques

Enamel-dentine fracture with pulp opening

Complicated crown fractures
#pic#
Tooth reconstruction with a composite
#pic#

Treatment decision-making criteria in pulp exposure

  • Tooth vitality
  • Duration of pulp exposure
    Pulp infection is often present when the exposed area is large or when more than 2 hours have elapsed since the injury. A dark red area of haemorrhage that is difficult to control is consistent with the presence of pulp infection. Pulp necrosis leads to the discontinuation of root development. This is an important fact to consider. However, an apical stop is needed for definitive endodontic repair.
  • Chances of achieving a good filling seal
  • Stage of root development
  • Presence or absence of additional tooth injuries
  • Age of the patient
    The further open the apical foramen, the better the chances of pulp healing and, thus, of hard tissue bridge formation and the better the outcome of pulp treatment.

Direct pulp capping

The presence of vital pulp tissue that is capable of regenerating is the basic precondition for direct pulp capping.
After pulp exposure, vital pulp tissue can be identified based on haemorrhagic signs:
If the pulp is healthy, pulp bleeding occurs spontaneously and can be controlled by careful haemostasis. If there is pulp inflammation, bleeding will be profuse and difficult to impossible to control.

The X-ray appearance of the affected tooth should not be different from that of, say, the contralateral tooth.

The possibility of perio-endo involvement must be ruled out.

According to the current state of knowledge, the size of the exposed area does not correlate with treatment outcome.
The presence or absence of bacterial invasion determines the success or failure of healing after pulp exposure (Kakehashi 1965).
This leads to the following practice recommendations:
  • Working conditions that minimise bacterial invasion
  • Rubber dam use for treatments in lower third of dentin near the pulp or in cases of pulp exposure
  • Efficient haemorrhage control
  • Effective cavity disinfection (with 5% sodium hypochlorite, etc.)
  • Use of antibacterial wound dressings
  • Cover filling material that prevents bacterial invasion
    When direct pulp capping is performed, immediate placement of a permanent filling is required. Temporary fillings do not provide an adequate seal and therefore allow bacteria to infiltrate the pulp.
Procedure
  • Create absolutely dry conditions using a rubber dam if possible
  • Clean the affected area with physiological saline solution
  • Carefully dry the area with a sterile cotton pellet
  • Control bleeding
    Effective haemorrhage control is especially important for prevention of clot formation because calcium hydroxide must come in direct contact with pulpal tissue. Blood clots restrict the formation of tertiary dentin and pulp healing, and they are breeding grounds for pathogenic bacteria. Furthermore, blood clots release chemotactic mediators of inflammation in pulpal tissues. This results in chronic pulpal inflammation and prevents healing.
    Haemorrhage control can be achieved using: Sterile cotton pellets,
    Hydrogen peroxide (3%),
    Sodium hypochlorite (2.5-5%),
    Calcium hydroxide (only a temporary medicated filling because it becomes permeated with blood and serum; secondary application of a fresh CaOH suspension that remains in situ is recommended before placement of the permanent filling) (Folwaczny et al. 1998).
  • Coverage of the pulpal wound with calcium hydroxide
    (calcium hydroxide suspension should be used instead of calcium hydroxide cement when performing direct pulp capping)
  • Sealant base (placed with low tension)
  • Composite sealant filling
    According to Maguire et al. (2000), the use of composite materials as sealant fillings doubles the average survival time of young permanent teeth. Glass ionomer cement is not suitable for this purpose.
Mineral Trioxide Aggregates (MTA)

Mineral trioxide aggregate (MTA) is relatively new as a commercial product. MTA is used in a number of endodontic indications. Applications for MTA range from direct pulp capping and repair of furcation perforations in the root canal to retrograde root filling, treatment of internal resorption and apexification.
MTA is a cement powder that reacts to form a colloid gel when mixed with water. Calcium hydroxide is released as the product hardens. A pH of 12.5 is then reached. Hardening of MTA is completed within around 4 hours.
The best known brand of MTA in Germany is ProRoot MTA, which is supplied by Dentsply DeTrey. Around 75% of the weight of ProRoot MTA is made up of Portland cement with a reduced gypsum fraction.
Portland cement is a conventional cement that can be purchased in any home improvement store.
Gypsum is added to Portland cement to slow the hardening of the cement. Since more rapid hardening is needed in dental applications, the weight percentage of gypsum in ProRoot MTA was reduced to around 5 %. Twenty percent of the weight comes from bismuth oxide, an X-ray contrast medium, which is added to the Portland cement. The particle size of ProRoot MTA is smaller than that of conventional Portland cement, and unwanted minor constituents are removed from the product.
Experimental studies show that ProRoot MTA achieves comparable and, in some cases, better results than calcium hydroxide. This is because MTA creates a tight seal that prevents bacterial invasion. It also has better mechanical stability than calcium hydroxide. Furthermore, MTA is not subject to resorption and it adheres better to dentin, thereby providing a tighter seal and more stable long-term protection than calcium hydroxide. The disadvantage of MTA is the lack of long-term study data.
MTA from the Angelus Company recently became available on the German market. Angelus MTA allows individual dosage of the required amount of product, which results in a considerable savings compared to ProRoot MTA.

Partial pulpotomy (partial amputation of the pulp)

Definition: Partial resection of the coronal pulp (depth: ca. 2 mm) while preserving healthy parts of the coronal pulp capable of regeneration.

In patients with incomplete root development, pulp necrosis leads to the complete arrest of root development. However, an apical stop is needed for definitive endodontic repair.
An important goal of treatment is therefore to ensure that a portion of the root pulp remains vital. If direct pulp capping is not possible, partial pulpotomy can be attempted as the second-line treatment.

It is assumed that bacterial invasion of the pulp by microorganisms in the saliva does not occur until two hours after the injury, and that the bacteria do no penetrate further than 2 mm into the pulp cavity. The type of bleeding at the amputation site is a deciding factor.

Indications

  • Young teeth with incomplete root development, especially after trauma
    The ability to control haemorrhaging from the pulpal tissue is a basic precondition for pulpotomy. In teeth with incomplete root development, it is essential to ensure the continuation of longitudinal root canal growth (apexogenesis).
  • In patients with complete root development, there are restricted indications for pulpotomy following pulp exposure.
    The goal of treatment in these cases is to remove bacterially colonized areas of the pulp that show signs of irreversible inflammation.
  • In cases where partial pulpotomy is the only means of preventing bacterial invasion.

Procedure

  • Disinfect the cavity with H2O2 (3%), NaOCl (5%) or chlorhexidine (2%).
  • Remove the pulp tissue using a sterile diamond bur that is continuously cooled with sterile saline solution.
    Rose-head burs and hand excavators were not found to be suitable for amputation purposes. Use of these instruments diminishes the chances of healing because rose-head burs result in torsion and hand excavators result in crushing of pulpal tissues.
  • After removing the pulp, hemorrhage is arrested using only a sterile cotton pellet, if possible.
  • The cavity is then filled with calcium hydroxide, and excess moisture is removed by compacting the calcium hydroxide suspension with a sterile cotton pellet.
  • This layer is coated with calcium hydroxide salicylate cement.
  • The use of phosphate cement or glass ionomer cement as a lining material is recommended.
  • As with direct pulp capping, immediate placement of a permanent filling that prevents bacterial invasion is also essential. Studies have shown that temporary fillings result in significantly lower rates of healing.

Cervical pulpotomy/high amputation

Cervical pulpotomy (removal of the entire coronal pulp) and high amputation (removal of the coronal pulp and part of the apical pulp) are two further methods used for preservation of pulp vitality. The more vital pulp tissue is preserved, the better the chances of continued root development. The procedure for these techniques is similar to that described for partial pulpotomy

Management of pulp wounds - summary

Stage of root formation Wound surface Duration of exposition Procedure Prognosis of different authors, summarised by Andreasen (1981)
apex open or
apex closed
small or large,
bleeding
under 4 hours direct pulp capping Healing with hard tissue
(71-88%)
apex open or
young teeth with completed roots
small or large,
well vascularised (not necrotic)
rather proliferative
up to app. 30 hrs "refreshment" until app. 2mm under wound surface, capping Healing with hard tissue
(96%)
apex open necrotic a few days to weeks pulpotomy
(displacement of wound surface into vital area)
Healing with hard tissue
(72%)
young teeth with completed roots necrotic a few days to weeks partielpartial pulpectomy
(until 1-2mm from Apex)
Healing with hard tissue
(90%)

(Gnoinski 1994)