Failure of Tooth Development: Prevalence, Genetic Causes and Clinical Features

In dental practice may be encountered a wide variability in the clinical dental phenotype of tooth number. Failure of tooth development at the bud stage causes tooth agenesis and reduction in tooth number in the dental arch which involves various complications. Tooth agenesis is one of the most common developmental anomalies of human permanent dentition and tends to run in families, may aggregate within families, suggesting a genetic cause. Tooth agenesis can occur in association with a variety of craniofacial syndromes, but it is also found as an isolated trait (familial or sporadic). Other tooth anomalies, such as tooth shape and size, delayed eruption of teeth, malposition, short roots or taurodontism, have been noted in association with non-syndromic tooth agenesis as well. Both the deciduous and permanent dentitions may be affected by missing teeth. Variations in the number of missing teeth can be determined by a mutation in one gene, by mutations in multiple genes, induced by local or systemically acting environmental factor, caused by a combination of gene mutations and environmental factors acting together, or by damage to chromosomes. As the number of missing teeth increases, so does the severity of clinical consequences and the impact on oral health–related quality of life.