Tetracycline pigmentation
Tetracycline is taken up by calcifying tissues, and then the band of tetracycline-stained bone or tooth substance fluoresces bright yellow under ultraviolet light.
Tetracycline staining. Note the chronological distribution of the dark-brown intrinsic stain.
The teeth become stained only when tetracycline is given during their development, and it can cross the placenta to stain the developing teeth of the fetus. More frequently, permanent teeth are stained by tetracycline given during infancy. Tetracycline is deposited along the incremental lines of the dentine and, to lesser extent, of the enamel. The more prolonged the course of treatment the broader the band of stain and the deeper the discoloration. The teeth are at first bright yellow, but become a dirty brown or grey. The stain is permanent, and when the permanent incisors are affected the ugly appearance can only be disguised.
When the history is vague the brownish color of tetracycline-stained teeth must be distinguished from dentinogenesis imperfecta. In dentinogenesis imperfecta the teeth are obviously more translucent than normal and, in many cases; chipping of the enamel from the dentine can be seen. In tetracycline-induced defects the enamel is not abnormally translucent and is firmly attached to dentine. In very severe cases, intact teeth may fluoresce under ultraviolet light. Otherwise the diagnosis can only be confirmed after a tooth has been extracted. In an undecalcified section the yellow fluorescence of the tetracycline deposited along the incremental lines can be easily seen. It is no longer necessary to give tetracycline during dental development. There are equally effective alternatives and it should be avoided from approximately the fourth month to 12th year of childhood. Nevertheless tetracycline pigmentation is still seen.
Tetracycline pigmentation. Hard section (left) shows the broad bands of tetracycline deposited along the incremental lines of the dentine; (right) same tooth viewed under ultraviolet light shows fluorescence of the bands of tetracycline.
Cytotoxic chemotherapy
Increasing numbers of children are surviving malignant disease, particularly acute leukemia, as a result of cytotoxic chemotherapy. Among survivors, teeth developing during treatment may have short roots, hypoplasia of the crowns and enamel defects. Microscopically, incremental lines may be more prominent, corresponding with the period of chemotherapy, but in extreme cases, tooth formation may be aborted.
Fluorosis
Mottled enamel is the most frequently seen and most reliable sign of excess fluoride in the drinking water. It has distinctive features.
Fluorosis. Moderate effects from an area of endemic fluorosis. Irregular patchy discoloration.
Distinctive features of dental fluorosis
• Mottling is endemic in areas where fluorides in the drinking water exceed about 2 parts per million, i.e. it has a geographical distribution
• Neighboring communities with fluoride-free water do not suffer from the disorder
• Only those who have lived in a high-fluoride area during dental development show mottling. The defect is not acquired by older visitors to the area
• Permanent teeth are affected; mottling of deciduous teeth is rare
• Mottled teeth are less susceptible to caries than normal teeth from low-fluoride areas
• A typical effect is paper-white enamel opacities
• Brown staining of these patches may be acquired after eruption
Fluorosis. Severe effects from an area of endemic fluorosis. Closer view showing irregular depressions caused by hypoplasia and white opaque flecks and patches.
Clinical features
Mottling ranges from paper-white patches to opaque, brown, pitted and brittle enamel. Clinically, it may be difficult to distinguish fluorotic defects from amelogenesis imperfecta when the degree of exposure to fluoride is unknown. There is considerable individual variation in the effects of fluorides. A few patients acquire mottling after exposure to relatively low concentrations, while others exposed to higher concentrations appear unaffected.
