DEVELOPMENT OF THE TEETH 



159 



of the dental lamina, entirely free from the oral epithelium (Fig. 165.) 

 The anlages of the first permanent molars appear at seventeen weeks 

 (180 mm. C H), those of the second molars at six weeks after birth, while 

 the anlages of the third permanent molars, or wisdom teeth, are not found 

 until the fifth year. The permanent dentition of thirty-two teeth is then 

 complete. 



Before the permanent teeth begin to erupt, the roots of the milk 

 teeth undergo partial resorption, their dental pulp dies, and they are 



Permanent second molar 



Deciduous molars 

 Mandibular canal 



Permanent first molof 



Permanent premolars 



Permanent canine 



Mental foramen 

 Permanent incisors 



PIG. 166. Skull of a five-year-old child, showing the positions of the decidual and permanent 



teeth (Sobotta-McMumch). 



eventually shed. Toward the sixth year, before the shedding of the 

 deciduous teeth begins, each jaw may contain twenty-six teeth (Fig. 166). 

 The permanent teeth are cut as follows : 



First Molars seventh year. 



Median Incisors eighth year. 



Lateral Incisors ninth year. 



First Premolars tenth year. 



Second Premolars eleventh year. 



> thirteenth to fourteenth year. 



Second Molars J 



Third Molars (Wisdom Teeth) seventeenth to fortieth year. 



