Third molar agenesis in young people between 14 and 20 years of age, Antofagasta, Chile/Agenesia del tercer molar en jovenes entre 14 y 20 anos de edad, Antofagasta, Chile

Agenesis is defined as the absence of teeth by single or sindromics genetic alterations. Third molar agenesis is associated to malformations and is considered a consequence of human evolution by several authors. Third molar are the teeth with greater percentage of agenesis along with seconds premolars and lateral incisors. The frequency varies between 9% and 37%, while Arboleda et al., (2006) indicate a 20% of agenesis. Literature indicates statistical variables percentage, by gender, dental arches, side and tooth, however few articles in original groups of Chile. The population in study consisted of 400 young people (200 men and 200 women) between 14 and 20 years of age patient of a clinic of orthodontia of the city of Antofagasta, Chile. All the patients had to be healthy, without any type of general and maxillofacial malformation, who had not presented infectious diseases that altered the odontogenesis and the periods of eruption, without exodontias of third molar and without previous orthodontic treatment to the panoramic x-ray examination. A 24.75% of cases of agenesis were determined, with a percentage of 12.63% of agenesis with respect to the total number of third molars and 1.58% of agenesis of third molar in relation to the total of teeth. Agenesis in the female predominates, at mandibular level, in the right side, of double type and being the prevalent tooth is mandibular right third molar, without appearing significant statistical differences to 95% of confidence. KEY WORDS: Anthropology; Dentistry; Agenesis; Third molar. Se define agenesia como la ausencia de dientes por alteraciones geneticas aisladas o sindromicas. La agenesia del tercer molar esta asociada a malformaciones y considerada por diversos autores, consecuencia de la evolucion humana. Son los dientes con mayor prevalencia de agenesia junto con segundos premolares e incisivos laterales. La prevalencia varia entre 9% y 37%, en tanto, Arboleda et al. (2006) senalan una prevalencia del 20%. La literatura senala variables estadisticas porcentuales, por genero, por arcada dentaria, por lado y por diente, con escasos articulos sobre grupos originarios de Chile. La poblacion en estudio consistio en 400 jovenes (200 hombres y 200 mujeres) entre 14 y 20 anos de edad pacientes de una clinica de ortodoncia de la ciudad de Antofagasta, Chile. Todos los pacientes debian ser sanos, sin ningun tipo de malformacion general ni maxilofacial, que no hubiesen presentado enfermedades infecciosas que alt