21 - abnormalities in the structure of the teeth. Types of structural abnormalities. Risk factors for the occurrence of structural abnormalities. Pathogenetic mechanisms

Defects in the structure of hard tooth substance (structural anomalies)

• Hypoplasia - defective built organic matrix leads to defects in thickness and enamel form

• Hypomineralisation - disturbed mineralisation of organic matrix leads to normal shape and thickness but poor mineralisation

• Hypomaturation - disturbance in maturation of enamel leads to normal shape and thickness but poor mineralisation

• Hyperpigmentation - permanent pathological correlation from the postponed pigments in the tooth structure and cannot be removed with external cleaning

hypoplasia

• defects in the build of organic matrix leads to defects in thickness and enamel form

Hypomineralisation

• disturbed mineralisation of organic matrix leads to normal shape and thickness but poor mineralisation

Hypomaturation

• disturbance in maturation of enamel leads to normal shape and thickness but poor mineralisation

Hyperpigementation

• permanent pathological correlation from the postponed pigments in the tooth structure and cannot be removed with external cleaning

Risk factors for occurrence of structural abnormalities

• genetic factors - defective genetic info encoding cells that make up tooth structure

• General factors - act during childhood and during fetal development, rickets, nutrient deficiencies, chronic infections

• Local factors chronic complications of untreated caries, trauma of primary tooth, local action of radiation

Mechanism and cause (etiology) of Hypoplasia

• Impaired function of ameloblasts, affecting the quality of their synthesised and secreted proteins and the amount of secreted matrix

• Cause - defect in genetic info, rubella, in premature infants, congenital allergies

Mechanism and cause (etiology) of Hypomineralisation

• Impaired function of ameloblasts where the defective matrix does not provide the correct mineralisation

• Cause - genetic diseases, toxic effects of fluoride, nephrotic syndrome

Mechanism and cause (etiology) of Hyperpigmentation

• Pigments of a disease process can penetrate among the matrix forming complex with appetite structures

• Cause - Hemolytic anemia (blood pigments), tetracycline (brown pigments), drugs for cardiovascular disease (blood pigments)