Bright white, yellow or brownish? Where does the tooth color or discoloration come from?
Our tooth color is genetically determined. The shape and position of the teeth also influence perception; for example, large teeth and a harmonious tooth position appear "whiter". The color impression is created by light reflection, partly on the outer surface of the whitish translucent (transparent) enamel, partly inside the tooth at the transition to the yellowish dentin.
The enamel is thicker in the area of the incisal edge than at the neck of the tooth and therefore whiter, but also more transparent. At the neck of the tooth and transition to the gums, many teeth appear somewhat more "yellowish" due to the dentin shining through.
In the course of life, the enamel becomes continuously thinner and the teeth consequently more yellow. In addition, discoloration on the teeth is caused by plaque, food residues, lifestyle habits (coffee, tea deposits), tar residues (smoking), and so on.
Furthermore, mineral disturbances occurring during the formation of the enamel, fluoride overdoses (e.g. dental fluorosis) or deposits, e.g. as medication side effects (e.g. antibiotics such as tetracyclines) can lead to whitish, yellowish or brownish color stains, which not infrequently can also be associated with structural anomalies such as grooves or mottling (e.g. molar-incisor hypomineralization). Such color deposits also occur in the dentine. Furthermore, leaky dental fillings or crowns, for example, promote cracks in the teeth, which can promote the penetration of unsightly (yellow or brown) colorants into the outer tooth structures.
Traumatic bleeding, e.g. after an accident (at least temporary blue discoloration of the teeth) or brown-black stains from dead pulp (tooth nerve) tissue (see above) or through release from root canal filling materials can also lead to translucent brown-black tooth discoloration from the inside of the tooth (the former pulp cavity).
Aesthetics is an individual perception
Beauty comes from a harmony of the overall image. The shape of the teeth and head are just as related as the color of the skin, eyes and teeth.
There are no beautiful teeth without beautiful gums. Beauty and health are closely connected. Every age has its own beauty. Many tissues change, beautiful is when the relations to each other remain.
Only healthy teeth are beautiful teeth
Unattractive tooth discoloration and gingivitis must be prevented regularly. This is best achieved by regular dental care twice a day with an electric toothbrush and suitable fluoride toothpaste (ApaCare® toothpaste with liquid enamel - see Dental Care Guide). Many colored plaque deposits nevertheless accumulate. These can be gently polished with a toothbrush once or twice a week from the age of 12 using a polishing paste instead of toothpaste at home (ApaCare® Polish).
At regular intervals, in addition to check-ups, the dentist should perform professional tooth cleaning or have it performed by dental auxiliaries. This is best done with professional polishing systems and powder blasting techniques using polishing powders made from synthetic enamel (e.g. ApaPearls®).
To bleach teeth, oxygen-releasing substances such as hydrogen peroxide or carbamide peroxide are used in the form of gels, often in conjunction with bleaching trays custom-made by the dentist. Depending on the concentration, exposure time and type of application, these act only on the tooth surface or also in the surface marginal layer or inside the tooth.
Since the Cosmetics Ordinance was amended on July 17, 2012, toothpastes for home use may only contain hydrogen peroxide up to a maximum concentration of 0.1%. The whitening effect is thus limited to insignificant effects. What remains is a certain acid effect and, with regular use, a roughening of the tooth surface, not infrequently with a tendency to even promote the accumulation of color deposits in the long term and accelerate enamel wear.
Whitening agents from the drugstore are therefore also very limited in their effect. Depending on the application, e.g. in the form of strips or sticks, unsightly stains may form on the teeth.
Sustainable bleaching results can only be achieved by the dentist. The dentist starts the bleaching therapy with a professional tooth cleaning and the treatment of carious lesions or leaking fillings, etc. Only the dentist can detect findings, such as the presence of a tooth decay. Only the dentist can assess findings such as exposed tooth necks and thin gums and then select the correct, gentle (responsible) bleaching technique.
Turbo bleaching techniques such as the use of very high percentage hydrogen peroxide (up to 40%), sometimes in combination with heat or light, have been scientifically discouraged because of possible pulp (tooth nerve) and root damage (so-called resorptions). Today, bleaching is usually done using individually prepared bleaching trays and e.g. 20-30% carbamide peroxide gels, which are gentle on the gums and are applied overnight for 3-10 days in succession. In case of side effects such as sensitivity or gingivitis, bleaching therapy is (temporarily) suspended. The bleaching agent thus penetrates into the tooth enamel, partially to the dentin, and oxidizes (cleaves) color substrates stored there (as far as possible, e.g. not in the case of fluorosis or tetracycline discoloration, etc.).
In addition, the prism-like structures of the enamel are roughened and also dissolved, which reduces light transmission from deep within the tooth and makes the tooth appear whiter-opaque. In the first one or two days after bleaching, the tooth becomes lighter solely due to the removal of water during bleaching. The bleaching result can therefore only be seen on the 3rd day after the preliminary completion of bleaching, although subsequent bleaching is possible at any time.
Long-term stabilization of the bleaching result
It is very important to close the roughness and pores on the surface of the enamel caused by the bleaching agent at the end of the bleaching therapy so that no color substrates can adhere or penetrate and the bleaching result lasts as long as possible.
This is achieved over a period of three weeks by wearing the bleaching tray daily with enamel pastes or repair pastes (not cleaning toothpastes!) such as ApaCare® Repair Intensive Repair.
The resulting deposition of white medical enamel (hydroxyapatite) on the tooth surface additionally promotes the bleaching result. It may be necessary to replace dental fillings or crowns with brighter ones after bleaching.
How long does the bleaching result last?
The enamel prisms are very slowly recrystallized by mineral exchange with saliva, thus repaired and increasingly regain their original transparency. Dyes can also be deposited on or in the teeth again.
The gentler and more sustained the bleaching (exposure time of the bleaching agent with the bleaching tray), the deeper the bleaching result, the less damage there is to the surfaces and the longer the recrystallization takes. Particularly with regular use of enamel pastes/repair pastes such as ApaCare® Repair Intensive Repair e.g. two to three times a week over and above the bleaching process, the results remain stable for years or recede only slowly.
Bleaching results achieved only on the surface via turbo bleaching technology often only last for a short time.
Can any tooth be whitened at any age?
Since the bleaching effect essentially affects the enamel, particularly impressive whitening can be achieved with thick enamel in young patients.
In older patients with thinner enamel or in the cervical area, on the other hand, it is often not possible to achieve lasting whitening. Many discolorations, such as whitish fluorosis stains or yellowish tetracycline discolorations, are also not bleachable. In these cases, it is advisable to bond plastic or ceramic veneers - which are modeled in the mouth or produced in the dental laboratory after taking an impression - to the teeth.
What to do if the tooth is discolored from the inside?
Indeed, internal tooth discoloration can occur, for example, with the death of nerve tissue (pulp) inside the tooth or also due to reactions of (root canal) filling materials. Some of these are also congenital, caused by drug side effects or accompanying deformities.
The usually dark, blackish-gray discolorations of decayed pulp tissue can often be bleached very successfully from the inside out. Before this, the dentist checks the root canal filling, which often has to be renewed before internal bleaching. Then, over a period of several days to a week, a permanent bleaching agent is inserted into the interior of the tooth and the tooth is sealed. In this so-called walking bleach technique, there is a continuous release of oxygen from the bleaching agent over many hours, which penetrates the pores of the tooth from the inside and breaks down and oxidizes the colorants. After removal of the bleaching agent, the tooth is tightly sealed and the bleaching is thus stable for a very long time in most cases.
Is it possible to bleach repeatedly?
The enamel is in a constant mineral balance with the saliva surrounding it in the oral cavity. Changes in the enamel prisms and micropores, which are also caused by bleaching, recede over time. External bleaching results are therefore usually not stable over time. In principle, bleaching applications can be repeated as often as desired. However, care should be taken to ensure that sufficiently long breaks of at least several weeks are observed between bleaching applications so that no permanent damage or roughening of the enamel occurs.
The older the patient, the thinner the enamel becomes over time, making bleaching results increasingly difficult. Teeth that cannot be whitened once or cannot be whitened sufficiently usually cannot be whitened even with repeated applications.
What to do if stains have occured during bleaching?
If the bleaching agent is applied unevenly or if the bleaching agent is exposed to inhomogeneous enamel, sometimes unattractive stain-like or line-like changes may occur on the enamel surface. In this case, it is urgently recommended not to apply bleach again in order not to further accelerate the stain formation. As a rule, these effects disappear within weeks due to remineralization effects from the saliva.
This can be supported and accelerated by applying/repairing enamel pastes such as ApaCare® Repair Intensive Repair using medication trays (see Expert Tip 4).
What to do in case of blue discoloration after accidents?
In case of fall injuries, blood vessels in the dental pulp (tooth nerve) may burst with subsequent bleeding, which can lead to blue discoloration of the teeth, similar to a hematoma. These regularly disappear without further intervention.
A check-up by the dentist to rule out tooth fractures or damage to the tooth nerve is recommended.