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 mola' 



Permanent premolars 



Permanent canine 



Mental foramen 

 Permanent incisors 



FIG. 1 66. Skull of a five-year-old child, showing the positions of the decidual and permanent 

 teeth (Sobotta-McMurrich). 



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 



Median Incisors 



Lateral Incisors 



First Premolars 



Second Premolars 



Canine \ 



Second Molars / 

 Third Molars (Wisdom Teeth) . . 



. seventh year. 



. eighth year. 



. ninth year. 



. tenth year. 



. eleventh year. 



. thirteenth to fourteenth year. 



. seventeenth to fortieth year. 



