A practical treatise on the technics and principles of dental orthopedia and prosthetic correction of cleft palate . Two impacted canine teeth. (Cryer) An impacted second premolar and a third molar. (Cryer) In Fig. 271 is most perfectly illustrated one of the possibilities which mayarise with impacted third molars. When first lower molars are moved distally at an early age, the crowns of thesecond molars, whose roots may not be wholly calcified, are pressed back with an Fig. Inverted third molar. (Cryer) inclination movement. It would seem, in this distal movement and inclination ofthe s
A practical treatise on the technics and principles of dental orthopedia and prosthetic correction of cleft palate . Two impacted canine teeth. (Cryer) An impacted second premolar and a third molar. (Cryer) In Fig. 271 is most perfectly illustrated one of the possibilities which mayarise with impacted third molars. When first lower molars are moved distally at an early age, the crowns of thesecond molars, whose roots may not be wholly calcified, are pressed back with an Fig. Inverted third molar. (Cryer) inclination movement. It would seem, in this distal movement and inclination ofthe second molar, that the overhanging distal surface of its crown, impinging andpressing down upon the mesio-occlusal angle of the third molar crown, which at CHAPTER LI. IMPACTIONS 365 twelve years of age usually lies imbedded in the apical zone without roots, mesiallyinclined, would tend to hold it down at that point, while the eruptive forces wouldtend to lift the distal portion of the crown and turn its occlusal surface forwardagainst the second molar. The ultimate calcification of its roots in that positioncauses them to extend back beneath the angles of the rami, with an impaction ofthe tooth which often demands a severe surgical operation for its removal. If ateight or nine years of age the first lower molars are forced back half the width of acusp, as has been recommended for the purpose of attaining a typically normalocclusion, the unerupted second molars whose roots
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