Non-Carious Dental Lesions

General classification of hard tissue pathologies

All diseases of the dentition are divided into developmental defects and acquired pathologies. While caries (caries) is a process of demineralization and destruction of the inorganic matrix that begins strictly after eruption, many non-carious lesions originate much earlier.

Such maxillofacial dysmorphisms can have various etiologies:

• Hereditary (caused by gene or chromosomal mutations);
• Multifactorial;
• Congenital/prenatally acquired (a striking example is fetal alcohol syndrome, which occurs against the background of systematic alcohol consumption by the mother during pregnancy).

Developmental defects can be isolated, associated (a combination of several defects), or syndromic (when they are part of multiple defects in Down, Wolf-Hirschhorn, Edwards, or Patau syndromes).

Disorders of tooth formation: quantity, shape, timing

Among non-carious lesions, an extensive group of anomalies of the dentition itself is distinguished. Pathological anatomy classifies them according to several key criteria:

1. Anomalies of quantity: this group includes adentia (complete absence), hypodontia, and oligodontia (an insufficient number of tooth germs), as well as hyperdontia (the presence of supernumerary elements).
2. Positional anomalies: the formation of impacted and retained teeth that cannot occupy the correct position in the dental arch.
3. Size and morphological defects: the development of abnormally large (macrodontia) or small (microdontia) crowns, pathological changes in root length, a non-standard number of cusps, and the fusion of adjacent tooth germs.
4. Deviations in eruption timing: both premature appearance (so-called natal teeth present in a newborn) and marked delay are possible. The latter often accompanies congenital hypothyroidism and gingival fibromatosis.

In addition, there is the problem of premature tooth loss, which is a characteristic diagnostic sign of conditions such as hereditary neutropenias and hypophosphatasia.

Enamel and dentin developmental defects

Qualitative defects of hard tissues are also classified as non-carious lesions. They can be divided into structural disorders and pathological pigmentations.

Structural disorders include:

• Enamel hypoplasia — partial or complete underdevelopment of the enamel layer;
• Amelogenesis imperfecta — a genetically determined disorder of enamel formation;
• Dentinogenesis imperfecta — a pathology of dentin layer formation.

Pigmentations (exogenous and endogenous) manifest as a persistent change in tooth color. This condition accompanies a number of severe systemic diseases: erythroblastosis fetalis, congenital porphyria, and various congenital liver pathologies. Special attention should be paid to so-called "tetracycline teeth" — a specific persistent staining of enamel and dentin triggered by the intake of tetracycline antibiotics during the period of tooth tissue formation and mineralization.

Associated anomalies and concomitant factors

Non-carious dental developmental defects rarely exist in absolute isolation. Very often they are associated with other anomalies of the orofacial region. For example, in Robin sequence (an associated defect including cleft palate, micrognathia, microglossia, and glossoptosis), the absence or retention of the maxillary lateral incisor is frequently detected.

Also, the condition of hard tissues is profoundly affected by developmental defects of the salivary glands (aplasia, duct atresia, polycystic disease, or ectopia). These anomalies often lead to the development of xerostomia ("dry mouth syndrome"). A lack of saliva severely impairs the natural washing of the teeth, making them vulnerable to the development of periodontitis and rapidly progressive caries.

Briefly: answers to topical questions

What else to study on this topic

• Morphogenesis and pathogenesis of dental caries
• Facial and jaw developmental defects (dysraphisms, cleft lip and palate)
• Congenital tongue anomalies (macroglossia, aglossia, tongue root struma)
• Developmental pathologies and tumors of the salivary glands
• The impact of xerostomia on the development of dental diseases

Other Topics in "Chapter 27. Diseases of the Dentofacial System and Oral Cavity"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.