title: Prevalence of pathologies related to impacted mandibular third molars.
abstract: OBJECTIVE
  Prevalence of cysts and tumors related to impacted third molars has been considered important because the risk justifies prophylactic extraction. This retrospective study aimed to evaluate the prevalence of cysts or tumors associated with impacted mandibular third molars (IMTMs) according to patients' age and gender.
  
  
  METHODS
  Over the period from August 2006 to August 2011, 20,802 third molars from 17,535 patients were removed. Among these, IMTMs without cysts nor tumors were classified as non-pathology group, and IMTMs with cysts and tumors were classified into pathology group. The prevalence of IMTMs and associated cysts or tumors was analyzed in patient groups stratified by age and gender. The pathology group patients were also classified according to histopathological findings and the corresponding age groups.
  
  
  RESULTS
  Radiographic signs of disease were detected for 176 lesions (0.846 %) in 165 patients. Of these, 135 (76.4 %) lesions were diagnosed as dentigerous cysts, 31 (17.6 %) as keratocysticodontogenic tumors, and 10 (5.7 %) as ameloblastomas. The prevalence of cysts or tumors tended to increase after 50 years of age, such as 7.27 % in 6th decades, 18.60 % in 7th decades, and 11.53 % in 8th decades, with a male predominance in older patients.
  
  
  CONCLUSIONS
  IMTMs in old age patients more than 50 years old has high possibilities of developing cyst or tumors especially in male patients. However, these results should not be used as the only evidence for justifying prophylactic extraction, and further studies should investigate the survival rate of IMTMs without any pathologic in older populations.
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, 375, SeoSukDong, DongGu, GwangJu City, 501-759 Republic of Korea.
authors.forename: Seung-Min
authors.initials: SM
authors.lastname: Shin
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Wonkwang University, Iksan, Republic of Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Choi
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, 375, SeoSukDong, DongGu, GwangJu City, 501-759 Republic of Korea.
authors.forename: Seong-Yong
authors.identifier: 0000-0002-7513-4404
authors.initials: SY
authors.lastname: Moon
keywords: Ameloblastoma; Dentigerous cyst; Impacted third molar; Pathological lesion; Surgical extraction