INFLUENCE OF ADJACENT TEETH ON IMPACTED 3RD MOLARS IN THE UPPER AND LOWER JAWS

Panoramic radiographs of 1834 patients older than 21 years were evalua ted for the prevalence of impacted teeth at different ages. The freque ncy of impacted teeth by age was constant, that is, the presence of co mpletely impacted teeth could not be related to age. The interrelation ship between the angulation of impacted teeth and the existence of adj acent teeth was studied in individuals older than 61 years. The angula tion of most of the completely impacted teeth in the upper-third molar region was horizontal when adjacent teeth were not present, whereas i mpacted teeth in the upper-third molar region showed vertical angulati on when adjacent teeth were present, suggesting that vertically impact ed teeth may become exposed by bone resorption or infection and should be removed. The angulation of impacted lower third molars was horizon tal irrespective of the presence of adjacent teeth. It appears that th e interrelationship between the angulation of completely impacted teet h and the presence of adjacent teeth is different between the upper an d lower third molar regions. The angulation of completely impacted tee th and the presence of adjacent teeth should be included in those crit eria which determine whether or not completely impacted teeth should b e removed.