Restorative therapies for dental trauma
Introduction: Dental trauma causes damage to hard tissues and
periodontal disease of the tooth as well as aesthetic damage, the therapeutic objective is to restore periodontal and pulp health to prevent complications and above all to restore the patient’s aesthetics.
- COLLAGE OF THE FRAGMENT:
Since the development of adhesive dentistry, reattachment of the fragment has become possible. This technique, described in 1964 by Chosack and Eidelman, has several clinical advantages:
- the color and morphology are identical;
- psychological, because the patient immediately finds his tooth;
- ease of implementation, with the following of a fast and reliable protocol.
After ensuring that the tooth and the fragment fit together perfectly, the latter is reattached edge to edge to the fractured crown.
The decision to glue a fragment can thus be guided by very simple criteria:
- (1) the recovered fragment represents more than 90% of the missing volume;
- (2) the fragment can be repositioned unambiguously on the fracture line.
- HOW TO CONDITION THE FRAGMENT AND THE SUPPORTING TOOTH?
- the fractured fragments are only slightly affected by the nature of the environment in which they are preserved.
- Physiological serum or, failing that, tap water or milk are valid conservation media.
- If the fragment has been kept dry, it will be necessary to allow the network to
dentin collagen to rehydrate before bonding by immersing it in physiological saline for a few minutes.
- The tooth and fragment must be freed from any organic surface film (macro-debris and/or protein film) before any bonding procedure.
- WHAT BONDING PROTOCOL?
- The surfaces (of the tooth and the fragment) are conditioned identically, using the usual adhesive systems.
- Preference is given to three-step adhesive systems, so-called fourth generation: etching with 35-37% Orthophosphoric acid for 30” to 45” on the enamel and
for 10” to 15” on the dentin, active application of the dentin adhesion primer for 20” to 30”, application of the adhesive. The adhesive must be spread in a single layer
fine (air spray) and not be polymerized. The fragment is then placed on the tooth and the whole is photo-polymerized
- In case the fragment is not complete, it is preferable to position the fragment, remove excess adhesive, polymerize, and then complete the missing portions by layering restorative composite, the enamel mass being generally sufficient
- Clinical experience shows that the quality of positioning, the intimacy of contact of the surfaces, associated with rigorous isolation of the operating field, are the key points of the prognosis
The only disadvantages of reattaching the fragment may be:
- possible discoloration of the fracture line (the patient should be warned not to abuse nicotine, caffeine, theine, etc.).
- dyschromia of the reattached fragment due to dehydration of the underlying dentin;
- If the procedure is not carried out rigorously, without an operating field or without respecting the protocol, there is a risk of the fragment detaching, and since it has already been treated, it will be more difficult to obtain a good second bonding, even if it will always be attempted.
- DIRECT RESTORATION TO COMPOSITE:
Clinically, trauma to anterior teeth generates class IV cavities. A fundamental concept in the success of direct composite restorations is respect for the original morphology of the tooth to be restored, and above all to achieve a natural appearance of the tooth that is as close as possible to natural teeth, thanks to composite layering techniques.
- It is strongly recommended to use lamination guide keys.
These keys, made of silicone and generally palatal for a class IV cavity, can be manufactured according to different protocols:
- directly in the mouth, based on the initial morphology of the tooth to be restored (replacement of an existing or temporary filling whose morphology is deemed satisfactory)
- indirectly on a model on which the creation of a wax-up will have made it possible to recreate an aesthetic and functional dental anatomy.
- The palatal key will then allow the palatal face of the tooth to be restored to be placed in the correct position and thus start the stratification according to the appropriate anatomy.
- The second step consists of locating and constructing the proximal face(s).
- Next comes the actual stratification.
- the dentin core is first recreated dentin stratification, is established according to the real and not assumed histo-anatomy of the tooth
- For the reconstruction of the enamel layer, it is important to know that a young patient will have a greater thickness of enamel (approximately 1 mm), an adult patient an intermediate thickness (approximately 0.5 mm), an elderly patient a lesser thickness (between 0.2 and 0.5 mm). Similarly,
The younger the patient, the more opaque and therefore brighter the enamel is (the teeth appear whiter). Adult and older patients most often require the use of so-called enamel masses.
“neutral” (slightly translucent), sometimes more translucent (more grayed appearance).
- The enamel-dentin junction – or, more precisely, the enamel-dentin complex (natural organo-mineral layer that binds enamel to dentin) is also recreated by means of a thin layer (0.2 mm) of translucent and fluorescent fluid composite interposed between the dentin and enamel layers. The reproduction of this complex significantly influences the light reflection/transmission in the composite and allows for increased mimicry.
- When it comes to choosing materials, composites with the best mechanical qualities are preferred for dentin stratification; so-called micro-hybrid composites are then the benchmark choice.
- For enamel layering, micro-hybrid composites can be used, but it is advisable to employ a homogeneous nano-hybrid composite for the
last layer of enamel (small fillers of the same volume). This more recent family of composites combines both good mechanical properties (but often inferior to micro-hybrid composites) and unrivaled optical properties and polishability
- The finishing and polishing steps complete the sequence. They are just as crucial as the actual lamination and should not be
neglected. The final morphology, surface condition and final polish depend on it and constitute an important part of the aesthetic aspect of the restoration.
- FACETS :
For losses of bulky substances increasingly used and indicated in particular thanks to the use of feldspathic ceramics has a modulus of elasticity of 60 to 70 GPa, very close to that of enamel, which is 80 GPa.
Composite resins, by comparison, have an average rigidity of 20 GPa, which, from our point of view, limits their use to direct restorations.
- TREATMENT OF DYSCHROMIA :
Dental dyschromia is a common consequence of trauma. It most often affects an incisor, appears immediately or delayed (from a few days to a few years post-trauma) and can result from various phenomena:
- an initial post-traumatic pulp hemorrhage revealing a “pink” appearance
“, which can be reversible, the tooth retaining normal vitality and color in these favorable situations.
- An intrinsic, permanent, “grey” and more or less marked coloration is due to the fixation in the dentin of ferric ions from the degradation products of hemoglobin (hemosiderin, hemin, hematin, and hematoidin);
- dentin fixation of proteins resulting from pulp necrosis;
- iatrogenic etiologies, secondary to incomplete endodontic treatments (uncleaned pulp horns in particular) or to the use of chromogenic canal or coronal filling materials;
- – finally and in the longer term, the reactive apposition of dentin, triggered in response to pulp inflammation and resulting in the complete obliteration of the canal system, produces a modification of the optical properties of the tooth which becomes more and more opaque and saturated.
Tooth whitening is the result of the action of hydrogen peroxide. This active agent can be applied directly or as the product of a chemical reaction involving carbamide peroxide or sodium perborate. Hydrogen peroxide acts as a powerful oxidant through the formation of free radicals and superoxide anions (H+, O2–, HO2-, HO–, HOO–).
These highly reactive molecules are capable of splitting the long chains of chromophore molecules into shorter, more soluble and less colored chains.
We can therefore understand why the colorations caused by the migration of metal ions (silver cones, amalgams) cannot be removed by this type of chemical reaction.
The application of whitening products can be carried out on the external (vesical enamel) and/or internal (dentin of the pulp chamber) dental surfaces.
Caution and clinical common sense currently lead to the use of low-concentration products (4-6% hydrogen peroxide, 10-12% carbamide peroxide, sodium perborate + water), without the addition of heat. The results are certainly obtained less quickly, but they are potentially perfectly equivalent and generally even more durable. It should be noted, however, that, in principle, the results remain ephemeral (1 to 5 years of stability on average) and that the treatments will in any case have to be renewed many times during the patient’s life, an additional reason to favor approaches considered to be the least aggressive.
Tooth whitening techniques can therefore rightly be considered as non-invasive or minimally invasive techniques in the treatment of post- traumatic dyschromia . Coupled with direct composite restorations, they offer a therapeutic solution to be considered as a first-line treatment compared to any prosthetic alternative. However, a period of 2 to 3 weeks should be respected when adhesive techniques must be implemented after whitening. The remineralization of the superficial enamel is thus completed and bonding can be carried out under optimal conditions.
Restorative therapies for dental trauma
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