Tooth discoloration is a pathological condition accompanied by a change in the natural color of teeth as a result of exogenous and endogenous factors. Teeth can acquire yellow, brown, gray, pink, black, red tint. Often, along with disease, enamel demineralization is detected, accompanied by hyperesthesia. Diagnosis includes collection of complaints, physical examination, radiography, EOD, thermography. To eliminate the pigmentation of teeth, professional cleaning is performed, intra-channel and external bleaching is carried out, or natural color is restored by prosthetics.
Tooth discoloration is a persistent staining of teeth that occurs due to the effects of general or local factors. To date, tooth discoloration is a very common pathology. Discolorites are detected in 85% of young people, which is associated with poor nutrition, bad habits, injuries. In men, tooth discoloration is detected in 60%, in women – in 40% of cases. Among the main causes of discoloration are unsatisfactory oral hygiene, nicotine and drug pigmentation, injuries, staining of depulpated teeth with silers based on iodoform, resorcinol-formalin. Patients with dental pigmentation of combined etiology are more likely to go to dentistry. A close correlation has been established between the color of teeth, the level of hygiene and the degree of enamel resistance.
Factors affecting both the stage of follicular development and after teething can provoke tooth discoloration. Taking tetracyclines by a pregnant woman causes persistent discoloration of temporary teeth in a child. This is due to the fact that tetracyclines, being chelated calcium salts, are able to penetrate through the placenta, while accumulating in the bones and hard tissues of the tooth in the phase of their mineralization. The depth of tooth discoloration largely depends on the total dose of the drug.
Since the composition of enamel and dentin practically does not change over time, yellow-brown staining remains a permanent mark, indicating the endogenous origin of tooth discoloration. In preschool children, tetracycline intake also causes tooth discoloration, which is often observed in patients with cystic fibrosis. Dimethylchlortetracycline gives teeth a richer color, oxytetracycline has a less aggressive effect on tooth tissue.
In hemolytic disease of newborns, tooth discoloration develops due to Rh-conflict between maternal antibodies and fetal erythrocyte antigens, resulting in hemolysis characterized by massive destruction of erythrocytes. Excessive amounts of indirect bilirubin are deposited in dentin and enamel, causing their staining. Endogenous tooth discoloration occurs in children with porphyria. Due to a violation of the metabolism of porphyrin and its precursors, an increased synthesis of pigment is observed. The accumulation of porphyrin in the dentin leads to a change in the color of not only temporary, but also permanent teeth.
In the postnatal period, food dyes and tobacco smoking become the causes of tooth discoloration. As a result of traumatic damage, a rupture of the neurovascular bundle may occur. Intrapulpar hemorrhage leads to the destruction of red blood cells. The diffusion of iron sulfide and pulp decomposition products into the dentine tubules causes tooth discoloration. Filling of root canals with resorcinol-formalin paste, prolonged contact of the iodoform–based material with the walls of the root canal, the use of silver amalgam, the remnants of endogermetic on the walls of the crown cavity of the tooth – all these factors of iatrogenic origin can also cause persistent pigmentation of teeth.
Classification and symptoms
According to the etiology , tooth discoloration is conditionally divided into 2 groups:
- Endogenous. This category includes discolorites with hemolytic disease of the newborn, porphyria, as well as due to tetracycline intake.
- Exogenous. The main causes are food and drug dyes (chlorhexidine bigluconate, etacridine lactate), injuries, violation of the protocol of endotherapy.
With hemolytic disease, the color of the teeth varies from gray-blue to green or brown. Over time, the intensity of tooth discoloration decreases. Hemolytic disease is indicated by a violation of the enamel structure, since bilirubin deposits disrupt the processes of histogenesis. During examination, along with the pigmentation of the teeth, signs of systemic hypoplasia are revealed. If the pigmentation of the teeth occurred due to the intake of tetracyclines by a child or a pregnant woman, the teeth become yellow-gray. As a result of the oxidation of tetracycline under the influence of light, the intensity of staining increases. Tetracycline pigmentation of teeth is detected in both temporary and replaceable bite. Sometimes color change is combined with systemic hypoplasia.
In erythropoietic uroporphyria, teeth turn red. Patients have no hair, photosensitization occurs, as free uroporphyrinogen, oxidized, accumulates in the skin. Blisters are found on the child’s body, after opening which the ulcerative surface is exposed. With exogenous pigmentation of teeth with food dyes, the color change directly depends on the nature of the food consumed. When smoking tobacco, deposits of dark brown or black color are found on the teeth. The oral surfaces of the teeth are subjected to maximum staining.
With pulp necrosis due to traumatic damage, the tooth becomes gray. Resorcinol-formalin paste and preparations based on iodoform cause persistent pigmentation of teeth, while the crowns are colored pink. After the restoration of the palatine surface with silver amalgam, the enamel of the teeth becomes gray and dull.
The diagnosis of tooth discoloration is made based on the patient’s complaints, anamnesis of the disease, clinical examination data, and the results of additional studies. In case of hemolytic disease of a newborn, a dentist locally detects tooth discoloration in combination with signs of systemic hypoplasia. Probing of colored areas is painless. EOD indicates the vitality of the pulp. The surface of a pigmented tooth does not fluoresce under the influence of ultraviolet rays. The anamnesis of the disease confirms the etiology of tooth discoloration. In infants at birth, blood tests show an increased level of indirect bilirubin, a decrease in hemoglobin and the total number of red blood cells.
With tetracycline pigmentation of teeth, staining is observed not over the entire area of the crown, but only in the part where mineralization processes occur at the time of taking the drug. Depending on the duration of administration, the type of drug, the total dose, the color of the crowns varies from yellow to dark brown. Over time, an increase in the intensity of tooth discoloration is detected only on the cheek surfaces of incisors, canines. Probing of colored areas is painless, EOD confirms the viability of the pulp. Tetracycline pigmentation of teeth fluoresces under the influence of ultraviolet rays.
With porphyria, not only temporary, but also permanent teeth become purplish-red. Blindness, lack of hair, photosensitization, urine staining in red, the presence of similar symptoms in close relatives – all this confirms the hereditary etiology of discoloration. If smoking is the cause of tooth discoloration, the Green-Vermillion index indicates an unsatisfactory level of hygiene. In the presence of pigmented deposits in the cervical areas, the marginal gum is involved in the inflammatory process, as indicated by the positive results of the Schiller-Pisarev test.
If the pigmentation of the teeth occurred due to the rupture of the neurovascular bundle, the tooth becomes gray. The vertical percussion is positive. Pathological mobility may be observed. When opening the pulp chamber, probing of the canal mouths is painless, putrid masses are detected in the channels. The thermal test is negative. EOD indicators in the range of 100 µA and higher, which signals the death of the pulp. If a long period of time has passed from the moment of injury to the patient’s visit to the clinic – 3-6 months, destructive periapical changes are detected on the X-ray.
To make a final diagnosis, it is necessary to differentiate between different types of exogenous and endogenous tooth discoloration, to conduct a differential diagnosis of the disease with imperfect amelogenesis, Stanton-Capdepon syndrome, necrosis and erosion of enamel. During the examination, there may be a need for additional consultation of narrow specialists (pediatrician, geneticist).
The main methods of eliminating tooth discoloration are bleaching, lamination of vestibular surfaces with adhesive or ceramic veneers, restoration of natural color by manufacturing metal-ceramic or metal-free structures. Before starting the treatment of tooth discoloration, the oral cavity is sanitized. Dental deposits are removed using a pneumatic scaler and an air-abrasive system, the principle of which is based on cleaning the enamel with a mixture of water and sodium bicarbonate under the influence of compressed air under high pressure.
The method of internal (intra-channel) and external whitening is used for deep pigmentation of teeth. For this purpose, hydrogen peroxide is used. Activation of oxidation reactions occurs under the influence of light or laser. It may take several visits to eliminate tooth discoloration. One visit is sufficient only in the case of traumatic periodontitis, when tooth staining occurred due to the penetration of putrefactive pulp decay products deep into the dentine tubules.
With low enamel resistance, bleaching is contraindicated. In this case, orthopedic methods are used to restore the aesthetic component – microprosthetics or the manufacture of complete ceramic crowns. The prognosis depends on the etiology of tooth discoloration. Tetracycline teeth and discolorites that have arisen due to the oxidation of metal intra-channel pins and silver amalgams are practically not amenable to bleaching.