Aesthetic therapies for dyschromia

Aesthetic therapies for dyschromia

Introduction-definition

Dental dyschromias are abnormalities in the color of teeth that result from mechanical, chemical or biological alterations. These alterations can occur during or after tooth formation, with or without alteration of the structure of dental tissues.

They are said to be partial when they affect one or a few teeth, total if they affect all the teeth.

Etiology

Dyschromia can have several origins, for this reason practitioners must have a good knowledge of the various causes of dental discoloration, in order to make a correct diagnosis and establish a treatment plan adapted to each case.

Dyschromia of external origin or extrinsic dyschromia
Extrinsic factors

Some products can cause more or less superficial staining of the teeth. These extrinsic stains are mainly located on the enamel surface

We quote:

Bacterial plaque

It is a soft, colored deposit that accumulates on dental surfaces. When this soft deposit mineralizes, it forms tartar, which can be white or yellowish, but can also be colored differently by food pigments or tobacco.

Tobacco

Tobacco, whether smoked or chewed, leaves dark yellow to black discolorations, mainly in the cervical third of the teeth. Tobacco products (tars) dissolve in saliva and then easily penetrate the pits and grooves of the enamel, as well as any bacterial plaque or tartar present.

The Food Factor

Foods contain dyes that, if ingested repeatedly, can be deposited in the fissures and grooves, as well as the pits of the teeth. Certain foods are more likely to stain teeth:

Drinks: tea, coffee, colas, etc., they cause brown discoloration on the enamel surfaces.
Fruits: mainly red fruits such as cherries cause a blue-purple colour, blackberries and raspberries cause red or purple deposits (the same applies to beetroot).
Spices: curry, saffron, red pepper give yellow or red colors.
Coloring by medicinal and industrial solutions

Brown discoloration may be observed after prolonged use of chlorhexidine-based solutions, or fluoride solutions, as well as mercury or iodine-based products.

Iron, manganese and silver stain teeth black.

Predispositions to these extrinsic colorations

These colorations can persist due to the accumulation of local factors:

Enamel defects: the presence of micro pits and grooves, cracks, imperfections on the external surface of the enamel allows the accumulation of coloring foods, tobacco and other topicals
Salivary dysfunction
Lack of oral hygiene.

Dyschromia of internal or intrinsic origin

Intrinsic staining is caused by the presence of coloring agents within the dental organ itself, particularly at the level of the enamel-dentin complex, or by anomalies in the formation of enamel or dentin.

colorations linked to acquired pathologies

The main causes of acquired pre-eruptive dyschromia are linked to poisoning by fluoride and tetracyclines.

Fluorosis

It is an alteration of the structure of the hard tissues of the tooth, following chronic ingestion of excessive doses of fluoride during the formation of dental germs.

Discolorations due to tetracyclines

Tetracyclines are broad-spectrum antibiotics that can cross the placental barrier and bind to bone and dental tissue during gestation or after birth.

A chelation phenomenon then occurs between the tetracyclines and the calcium ions during the mineralization of the tooth, causing changes in color ranging from yellow to dark gray or brown.

Dyschromia of genetic origin
Amelogenesis imperfecta

Amelogenesis imperfecta is a hereditary disease of multigenic etiology. The enamel is not formed correctly, either in terms of quality or quantity. Its thickness is thinned, revealing the underlying dentin. It affects the deciduous and permanent dentitions.

There are three forms of amelogenesis imperfecta:

Hypoplastic amelogenesis imperfecta which is characterized by a lack of enamel. The teeth appear yellow, reddish or yellow-brown.
Hypomineralized amelogenesis imperfecta which is characterized by very brittle enamel. Tooth color varies from chalky white to yellow-red or brown.
And hypomature amelogenesis imperfecta: which is characterized by enamel of reduced hardness. Its thickness is normal, it has an appearance ranging from chalky white to brown.

Aesthetic therapies for dyschromia

Dentinogenesis imperfecta

Dentinogenesis imperfecta is also an inherited disease, where the genes encoding dentin mineralization proteins are affected. Both sets of teeth can be affected.

There are different types of dentinogenesis imperfecta, the most common being dentinogenesis imperfecta type II, in which the deciduous dentition is more severely affected than the permanent dentition.

The teeth appear opalescent, yellow or gray-brown in color.

Congenital dyschromia

Certain congenital pathologies can cause dental dyschromia.

Erythropoietic porphyria

This rare disease causes an overproduction of porphyrin in the bone marrow, red blood cells, teeth, etc.

Affected teeth, mainly the deciduous dentition, show a red to pinkish-brown coloration. Red fluorescence under ultraviolet light can then be observed.

Hyperbilirubinemia

Hyperbilirubinemia is a neonatal liver disease causing yellow, brown, gray or bluish discoloration of baby teeth.

Cyanotic congenital heart disease

Patients with cyanotic congenital heart disease have upper incisors that are white-blue in color.

Dyschromias related to pulp-dentin treatments

Dental caries and restorative materials are responsible for 50% of unsightly tooth discoloration. Silver amalgam is the material most commonly implicated in unsightly tooth discoloration.
Unsuitable or poorly performed endodontic procedures (insufficiently open chamber, poorly performed hemostasis) are the cause of secondary dyschromia.

Aesthetic therapies for dental dyschromia

In the treatment of dental dyschromia, two possibilities are available to us:

Either a therapy by chemical whitening of teeth
Or even aesthetic therapy using glued veneers.

While remembering that a simple brushing or scaling followed by polishing can remove the discolorations from the surface of the enamel when they are due to dental plaque.

Chemical teeth whitening

Tooth whitening can only be considered after having carefully studied the form of dyschromia to be treated, and adapting the form of application of the whitening product to it . For this, before undertaking this type of treatment, it will be necessary to make a complete analysis of the case that presents itself, and in particular to ensure the vitality or non-vitality of the teeth .

chemicals used for tooth whitening

We cite the most used chemical substances:

_Hydrogen Peroxide or Oxygenated Water ( H2O2 )

It is used in concentrations of 100 or 130 volumes, which corresponds approximately to 27.5 to 35% by weight of hydrogen peroxide.

H2O2 is _the main agent used to whiten dental structures. This molecule is unstable and prone to breakage, releasing nascent oxygen most often, or perhydroxyl ions (HO2– ⁾_,_both of which have significant oxidizing power.

Following the instability of H2O2 _,_two reactions are then possible:

H ₂ O ₂H ₂ O + 1/2O ₂

H ₂ O ₂HO ₂^– + H ⁺

Sodium perborate ( BO ₃ Na ₄ H ₂ O )

This lightening product comes in the form of a fine, antiseptic, chemically stable white powder. In the presence of water, it reacts to produce metaborate and release native oxygen.

The final reaction always results in an oxidizing molecule, resulting from the degradation reaction of hydrogen peroxide.

_Carbamide Peroxide or Hydrogen- _Urea Peroxide ( H2NCONH2 )

It is obtained by syncrystallization of H2O2 _{and urea in the form of}_colorless and odorless crystals . It is today the most used product in tooth whitening techniques.

Adjuvants

Are products added to lightening products in order to increase their effectiveness and keep them in gel form.

Thickening agents (such as carbopol: polymer resin of acrylic acid).

Present in pulped tooth whitening gels, during tray treatments. These agents allow the whitening product to be kept close to the tooth surface for as long as possible, to gradually release the oxidizing agents.

Glycerin, to increase the viscosity of the preparation and facilitate handling.
Scented solutions to make the product more enjoyable for patients. These aromas are often present in the form of mint.
Stabilizing agents

All solutions contain stabilizing agents in various forms such as citric acid or phosphoric acid. These agents allow for better endurance and stability of the lightening products. In return, they have an acidifying effect on the pH of the solution.

Other substances not disclosed by the manufacturers are also incorporated.

How do tooth whitening chemicals work?

Whitening techniques are all based on the permeability of enamel and dentin, allowing the diffusion of agents intended to eliminate or oxidize the dyes.

Most chemical agents that allow the degradation of the coloring substance through the release of nascent or native oxygen, use the principles of oxidation-reduction between the coloring substance and the bleaching molecule.

This native oxygen will penetrate into the mineralized dental tissues, without altering them, and degrade by fragmenting into smaller lighter molecules, the pigments responsible for the coloring. The activation of this chemical reaction is done either by a physical process, by the supply of heat or light radiation, or by a chemical reaction associating sodium perborate or persulfates.

Tooth whitening on vital teeth or pulped teeth

Whitening on vital teeth is based on the semi-permeability of the enamel and is done externally .

Before undertaking any treatment, it is important to know that every therapeutic approach has its indications and contraindications.

Indications for tooth whitening on vital teeth

All teeth with moderate dyschromia :

dentinogenesis imperfecta
congenital discolorations
permanent acquired colorations

fluorosis
tetracyclines
discolorations due to filling materials, such as silver amalgams.

Contraindications to whitening on vital teeth

cases of very pronounced dyschromia
in young patients under 15 to 16 years old, due to the importance of the pulp volume
teeth showing hypersensitivity during the preoperative examination
teeth with cervical wear lesions or occlusal dentinal islands from abrasion
in heavy smokers
teeth restored with large coronal fillings
in cases of deep periodontal disease.

operating protocol
pre-operative examinations

rigorous clinical examination, with diagnosis of the type of coloration
caries assessment
periodontal assessment
X-ray examination is an essential step before applying chemicals; it also allows an assessment of pulp volume.
Intraoral photographs represent an essential step before any treatment of dyschromia, in order to better evaluate the effectiveness of the treatment. And the best would be to take

these photos with a tint chart, which will serve as a reference.

On the other hand, all defective restorations will be replaced by a temporary filling material, which will be replaced by a definitive restoration at the end of the treatment. The shade of the new material must therefore match that of the lightened tooth, particularly concerning composites.

Aesthetic therapies for dyschromia

Ambulatory technique or mediate technique

Can only be performed in cases of light coloring .

Surgical technique

In the outpatient technique, the gel containing the lightening chemical is applied and held in place using thermoformed trays prepared in the laboratory.

It will then be necessary:

take an alginate impression
The prints are then cast in hard plaster
Place light-curing resin spacers at the interdental spaces and 1 mm from the gum. These spaces are intended to prevent gingival irritation during tooth whitening.
then place a sheet of polyethylene (about 1mm thick) on the plaster model, place the model in the thermoformer, and press onto the model.
then cut the edges of the gutter at the level of the marginal gum,
then try the gutter on the patient, it must cover the cervical limit by 1 to 2 mm, and must be perfectly adapted in order to avoid any leakage of the whitening product.
The practitioner then chooses the lightening product according to the clinical case. There are two groups of products:
carbamide peroxide gel at concentrations ranging from 10 to 22%
gel based on hydrogen peroxide at concentrations ranging from 3 to 7.5%
The practitioner then recommends to the patient:
to brush your teeth before putting in the aligners
to place the product in the gutters
to properly adjust the gutters
to eliminate excess
For low concentration products (10-16% carbamide peroxide or 3-4% hydrogen peroxide), it is recommended to wear the tray all night, for 2-3 weeks.

for more concentrated products, the action of the product being faster, the patient will wear their gutters for approximately 1 hour per day for 10 days.
When removed, the gutters will be properly rinsed with cold water and the teeth thoroughly cleaned.
The practitioner monitors the progress of the treatment every 5 to 6 days.

Noticed

Rather, it is recommended to lighten both arches separately, and preferably the upper arch first.

the practitioner will carry out a check at the end of treatment:
of the color obtained, in comparison with the photos taken
performing tooth polishing with polishing paste
fluoridation may be recommended.
Post-operative risks

Lightening by the outpatient method can be the cause of:

of dentin sensitivities
gingival, lingual and even throat sensitivities
burning sensations

It is therefore recommended not to use highly concentrated products for outpatient treatment.

Chairside technique or immediate technique

Pre-operative steps
performance of a clinical assessment, does the case present a favorable indication for lightening treatment?
carrying out a radiological assessment
pre-operative photographs taken using a reference shade guide.
and carrying out careful descaling.
Surgical technique
installation of a waterproof and effective gingival protection, preferably using a photopolymerizable dam, in order to avoid any irritation of the periodontal tissues
Polish the surface of the teeth using a cup and polishing paste composed of pumice and whiting mixed with water (pre-made pastes may contain glycerin which reduces the effectiveness of the peroxide).
place a cheek retractor, in order to protect the inner side of the cheeks
then place the whitening agent on the vestibular surfaces of all the teeth or just the teeth concerned.
Leave the product to act for between 10 and 30 minutes, depending on the manufacturer’s instructions and the concentration of the lightening product.

The lightening product is usually hydrogen peroxide, in gel form.

and concentration between 25 and 35% (therefore high concentration).

The operation is repeated on average 3 to 4 times.
For some authors, activation by light from halogen or plasma lamps or simply the surgical light placed near the surface of the teeth, can improve the reaction.
At the end of the session, have the patient rinse thoroughly to completely remove the lightening agent.
use baking soda as a rinse, which will neutralize the reaction.
control of the result after one week, using the reference shade guide.
This operation can be repeated 2 or 3 times, with a space of 2 to 3 weeks between each session, if the expected result is not obtained in a single session.
recommend that the patient eliminates colored and coloring foods (red sauce, coffee, etc.) and observes strict hygiene for several days.
application of fluoride (in gel form) for a few days to eliminate post-operative dental sensitivities.
Advantages of this technique
the results obtained are faster than with the outpatient technique (1 hour for the chairside technique = one week in outpatient care)
the result is immediate most of the time
protocol that is not very restrictive for the patient
the technique is under the control of the practitioner unlike outpatient care which escapes him.

Aesthetic therapies for dyschromia

disadvantage of the technique

Chairside whitening gels are highly concentrated and can cause post-operative tooth sensitivity. These tooth sensitivities are normally temporary, especially with the application of fluoride gel, but can sometimes last over time.
irritation of the periodontal tissues, particularly the gingival tissues if the dam was not watertight.

Tooth whitening on dead teeth

The whitening of the devitalized tooth is rather carried out intra-coronally, thus the permeability of the dentin allows the diffusion of the whitening product directly to the pigments, through the dentinal tubules.

Indications for tooth whitening on dead teeth

coloring appearing following a loss of pulp vitality, the origin of which could be:
trauma resulting in intrapulpal hemorrhage;
pulp necrosis;
to the use of intracanal medications;
to the use of certain root canal filling products
The impossibility of treating this coloration by extra-coronary lightening;
The observation of dense endodontic treatment, without apical or periodontal lesions;
A slightly decayed tooth;
The age of the patient: the younger the patient, the more open his dentinal tubules are and the better the penetration of the oxidizing agent in order to lighten the tooth;
Patient motivation

Contraindications of tooth whitening on dead teeth

On temporary teeth;
On permanent teeth of children with an unclosed apex, as well as on adolescents under 18 years of age;
During orthodontic treatment;
On teeth with periodontal disease, or having undergone periodontal treatment with root planing;
On teeth that have suffered violent trauma;
On teeth showing apical pathology, phenomena of internal or external root resorption;
On teeth revealing an enamel abnormality, hypoplasia, structural abnormality;
On teeth with a cracked root;
In pregnant or breastfeeding women;
If the patient has a known sensitivity or allergy to the active ingredients contained in the lightening agent used.

Operating protocol

Preliminary steps
X-ray

An X-ray is necessary, it allows us to visualize the integrity of the dental root, if it does not present any fracture, malformation, apical lesions, internal or external resorptions or any other pathology that could affect the root.

Finally, it allows us to observe the quality of the root filling. The latter must be dense, and reach the apex without going beyond it.

Aesthetic therapies for dyschromia

Aesthetic therapies for dyschromia

If the endodontic treatment is not satisfactory, it is best to repeat it. It will then be necessary to wait 7 days before starting the whitening steps.

unclogging and opening of the pulp chamber

The opening of the pulp chamber is done using rotating instruments used at high speed. The access cavity must be properly cleared. All remains of restorative materials, necrotic tissues must be removed.

The healthy colored dentin will be kept, at the risk of weakening the crown.

Protection of surrounding soft tissues

Agents used to whiten teeth are toxic to the mucous membranes.

In order to protect them, a surgical field must be placed around the tooth. There are two types of dam for this type of treatment:

The classic rubber dam: it is fixed to the tooth using a clamp. Its installation is long and delicate, and risks causing untimely bleeding, this risk being increased in the event of inflammation of the gum.
The photopolymerizable dam: it is placed on a previously dried gum. Its installation is very easy, using a syringe containing a fluid silicone. It hardens following its photopolymerization and must imperatively be associated with the installation of an automatic lip and cheek retractor.
Clearance of the canal entrance

The root filling must be reduced by 1 or 2 mm in the apical direction below the enamel-cement junction. It is possible to use for this a Gates drill bit for example, in slow rotation, or an instrument heated in the presence of gutta-percha.

Aesthetic therapies for dyschromia

isolation of the root canal filling

This insulation put in place before the lightening agent aims to prevent penetration

of the lightening agent inside the root, and its diffusion to the periodontium through

dentinal tubules.

The materials used can be:

either composite resins;
or even simple glass-ionomer cements (CVI) or glass-ionomer cements modified by the addition of resin (CVIMAR);
zinc oxyphosphate cements;
or simply using zinc oxide cement – -eugenol
or using MTA
Ambulatory technique or “walking bleach technique” or mediate

The outpatient technique uses the following lightening agents as lightening agents:

a pasty mixture of sodium perborate and distilled water (2 parts to 1 part), which will allow us to obtain a creamy consistency.

This mixture will be inserted into the pulp cavity using a mouth spatula, or an amalgam holder (used only for that) where cotton fibers will have been previously placed.

The mixture will then be crushed, the excess removed, and the edges of the cavity cleaned using a cotton ball.

A temporary filling will cover everything, it will be done using a waterproof occlusive dressing (composite, CVI, etc.), the more airtight the material, the better the prognosis for lightening.

The product will be left in place for 15 to 20 days.

Aesthetic therapies for dyschromia

or a mixture of sodium perborate and hydrogen peroxide (H2O2 ₎ in solution, dosed at 100 or 130 volumes _.

Then, soak a cotton ball with this solution, place it in the pulp chamber, and close it with an occlusive dressing. The product will be left in place for three to six days.

Renewal of the steps

After a few days or weeks, several situations may arise:

The clarification is satisfactory: it is not necessary to continue the treatment;
The clarification is encouraging: a renewal of the previous steps must then be carried out, until the desired clarification is achieved;
Lightening has not occurred, in which case it may be advisable to change the lightening products to other more effective products.
Chairside technique or immediate technique

This technique uses activators that will be applied to the lightening product. These activators are either thermal, light or more recently laser radiation.

Thermocatalytic technique

This technique relies on the direct addition of heat to the lightening agent. This increases its speed and efficiency of reaction, but also its risks and complications.

then place inside the pulp chamber cotton balls soaked in hydrogen peroxide (oxygenated water) at 100 or 130 volumes;
A heated metal instrument (Machtou plugger, mouth spatula, etc.) is then placed in contact with the cotton balls, while avoiding touching the dental walls, which risks causing cracks or secondary fractures.
an immediate release of gas then occurs, thus releasing the oxygen which will penetrate into the dentinal tubules;
the operation will be repeated several times (5 to 6 times) every 5 minutes, during the same session.
If the shade obtained is insufficient, then apply a temporary dressing and repeat the same operation at a later session.
Technique with photo activation

Light activators generate heat and thus potentiate the effect of hydrogen peroxide.

placed a cotton ball soaked in 35% carbamide peroxide in the pulp chamber of the affected tooth, previously prepared;
follow with light activation with either ultraviolet lamps (for photopolymerization) or plasma, an LED or halogen lamp and even a surgical light.

The results with this technique are most often disappointing.

Laser lightening technique

Aesthetic therapies for dyschromia

More recently, new laser protocols have been introduced for chairside whitening of dyschromic, pulpless teeth. The main effect of the laser is to warm the whitening gel.

The laser beam allows to obtain in 1 or 2 sessions, lasting no more than 30 minutes, very satisfactory results, for the lightening of pathological or acquired dyschromia of devitalized teeth, by activation of hydrogen peroxide at high concentration (35%).

The technique requires gingival protection using a light-curing dam.

Aesthetic therapies for dyschromia

Glued veneers

Chemical lightening treatments have no effect on dyschromia of genetic origin, and in certain cases of damaging dyschromia, where non-invasive or minimally invasive treatments have their limits; in these cases, veneers, in composite resin or bonded ceramic, are indicated.

definition of the glued facet

A veneer is a bonded partial restoration, most often used in the anterior sector. This covering is ultra-thin, and covers the visible face of the teeth. Currently there are two types of dental veneers:

ceramic veneers.
And the composite resin veneers

Indications and contraindications for bonded veneers

Indications

in cases of dental dyschromia that is not too damaging
some cases of dental fractures
cases of decaying caries, but which can be recovered without going through the prosthesis.
Contraindications
important parafunctions, such as bruxism.
significant proximal lesion and excessive deterioration.
deteriorating dentin dyschromia.
poor hygiene
periodontal pathology.
preparation limit not allowing good conditions for the bonding procedure.

glued veneers

Composite resin veneer
Advantages of composite resin veneers :
Composite veneers are quick to make. They are made in a single session when they are made directly on the teeth, or in two sessions when they are prepared indirectly, outside the mouth, in a laboratory.

They are inexpensive compared to ceramic veneers.

This type of veneer is reversible and retouchable when repairs are required over time.

Disadvantages of Composite Veneers
They do not offer the same aesthetic as ceramic.
They are not very resistant with a limited lifespan, between 4 or 5 years.
Ceramic veneer
Advantages of ceramic veneers .
Ceramic veneers generally give very aesthetic results . And the appearance, following the installation of ceramic veneers, is very natural.
Ceramic veneers are more durable compared to composite resin veneers.
They have a longer lifespan than composite resin veneers, from 10 to 15 years
they do not fade.
Disadvantages of ceramic veneers
They are more expensive than composite veneers.

Ceramic veneers are made indirectly only, and may require multiple sessions.
Aesthetic therapies for dyschromia.

Aesthetic therapies for dyschromia

Operating protocol

Throughout the preparation the practitioner should have the most conservative approach possible, since bonding allows for a much less mutilating preparation than a conventional crown.

The reduction should, as far as possible, be only enamel , the limits of the preparation should be in the healthy enamel. However, certain situations such as the presence of strong staining or very thin enamel thickness make dentin preparation obligatory.

fingerprinting
preparation in the veneer laboratory
Sealing sequence
Etching of dentin using 35% orthophosphoric acid for 15 sec.
rinsing and vacuuming excess water.
application of a primer by gentle brushing then removal of excess by suction.
application using a periodontal probe of a thin layer of adhesive resin
first photopolymerization.
removal of excess resin using fine-grain diamond burrs or low-intensity ultrasound.
On the prepared tooth, place the dental veneer which is a thin plate of the ideal shape and color of a tooth.

Working with optical aids allows the adhesive to be placed precisely on the boundary and excess to be removed.

Noticed

It is essential to observe good oral hygiene after the placement of dental veneers, by brushing your teeth at least twice a day, and reducing the use of coloring foods such as coffee and tea.

Good oral hygiene Regular scaling at the dentist Dental implant placement Dental x-rays Teeth whitening A visit to the dentist The dentist uses local anesthesia to minimize pain

Aesthetic therapies for dyschromia

Aesthetic therapies for dyschromia

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