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The effect of the developmental toxicants depends on the type of substance, dose, duration, and time of the exposure. The first few weeks of embryogenesis in humans is more susceptible to these agents. The embryogenesis is the most crucial time for the action of any teratogenic substances to result in birth defects.
Several inhalational anesthetic agents are used in dentistry, e.g., isoflurane, sevoflurane, desflurane, and halothane. [11] The most concerning from the point of view of its health impact, however, is nitrous oxide, an inhalation sedative commonly used in dentistry, particularly for children.
Fetal hydantoin syndrome, also called fetal dilantin syndrome, is a group of defects caused to the developing fetus by exposure to teratogenic effects of phenytoin. Dilantin is the brand name of the drug phenytoin sodium in the United States, commonly used in the treatment of epilepsy .
Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology caused by teratogens and also in pharmacology and toxicology.
Teratogens are classified in four main categories: Drugs in pregnancy – in addition to environmental chemicals, includes recreational drug use and pharmaceutical drugs. Vertically transmitted infections; Radiation, such as X-rays; Mechanical forces, such as oligohydramnios; Teratogens affect the fetus by various mechanism including:
Tetracycline use should be avoided in pregnant or lactating women, and in children with developing teeth because they may result in permanent staining (dark yellow-gray teeth with a darker horizontal band that goes across the top and bottom rows of teeth), and possibly affect the growth of teeth and bones.
Susceptibility to teratogenesis varies with the developmental stage at the time of exposure to an adverse influence. There are critical periods of susceptibility to agents and organ systems affected by these agents. Teratogenic agents act in specific ways on developing cells and tissues to initiate sequences of abnormal developmental events.
The international pictogram for chemicals that are sensitising, mutagenic, carcinogenic or toxic to reproduction. Reproductive toxicity refers to the potential risk from a given chemical, physical or biologic agent to adversely affect both male and female fertility as well as offspring development. [1]