Dental Anatomy 1: Classifications of Dentitions, Periods, and Teeth

Intro 

• Teeth are seperated into upper and lower arches 

  
  



• upper arch = maxillary and lower arch = mandible 

  
  



• Mandible = lower jar = movable 

  
  



• Midline = imaginary verticle line that divides the mouth into halves 

  
  



• The mouth = further divided into quadrants: 

  
  
  
  

  • Maxillary upper right 

    
    
  
  

  • Maxillary upper left 

    
    
  
  

  • Mandibular lower right 

    
    
  
  

  • Mandibular lower left  

    
    
  
  
  
  



• It's improtant to remember that the left is actually the patients right and patients left is actually our right  

  
  



• Occulsion = the action of the mandibular bottom teeth contacting the max. Upper teeth 

  
  



• The process of biting and chewing food = mastication 

  
  

1. Classification of Dentitions 

   
   

• Humans = heterodont = meaning we have different types of teeth that have different functions while masticating. A homodont would instead have all one same set of teeth.  

  
  



• Humans are also diphyodonts which means they have two sets of teeth 

  
  
  
  

  • Deciduous 

    
    
  
  

  • Permanent 

    
    
  
  
  
  



• Polyphyodonts = 2+ sets of teeth develop throughout life 

  
  



• Humans have two dentition phases. Deciduous and permnant 

  
  

  Decid = primary dentiton. Erupt around 6 mos till around 2 years old. 

  
  
  
  

  • 20 of them 10 on top 10 on bottom 

    
    
  
  
  
  
  
  

  • Perm = 32 perm teeth. 16 on top and 16 on bottom. 

    
    
    
    

    •  and they erupt from 6 yrs old to 21 years old. 

      
      
    
    
    
    
  
  
  
  

1. Classification of Teeth 

   
   

• Humans have 8 different types of teeth in the perm dentition  

  
  
  
  

  • 2 incisors = closest to ML  

    
    
    
    

    • Central and lateral incisors 

      
      
    
    

    • Biting, cutting, incising, and shearing. 

      
      
    
    

    • 4 per arch = 8 total in mouth 

      
      
    
    
    
    
  
  

  • 1 canine AKA cuspid 

    
    
    
    

    • 3rd tooth from midline 

      
      
    
    

    • Cutting, tearing, piercing, and holding 

      
      
    
    

    • 2 per arch = 4 total in mouth 

      
      
    
    
    
    
  
  

  • 2 premolars AKA bicuspids 

    
    
    
    

    • 4th and 5th teeth from ML 

      
      
    
    

    • 1st and second premolars = their names 

      
      
    
    

    • Tearing, holding, grinding 

      
      
    
    

    • 4 per arch = 8 total per moutn 

      
      
    
    
    
    
  
  

  • 3 molars 

    
    
    
    

    • 6th, 7th, 8  

      
      
    
    

    • First, 2nd, and 3rd molars 

      
      
    
    

    • First molar = 6 year old jmolar 

      
      
    
    

    • Second molar = 12 year old molar 

      
      
    
    

    • 3rd molar = wisdom tooth 

      
      
    
    

    • GRINDING 

      
      
    
    

    • 6 per arch, 12 per mouth  

      
      
    
    
    
    
  
  
  
  



• Decidious dentiion: 

  
  
  
  

  • 2 incisors = central and lateral incsicors 

    
    
    
    

    • Biting, cutting, incising, and shearing 

      
      
    
    
    
    
  
  

  • 1 canine = cuspid 

    
    
    
    

    • Cutting, tearing, piercing, holding 

      
      
    
    
    
    
  
  

  • 2 molars = first and second molars 

    
    
    
    

    • GRINDING 

      
      
    
    
    
    
  
  

  • NO PRE MOLARS, one less molar per quadrant. 

    
    
  
  
  
  



• 5 teeth per quadrant, 10 per arch = 20 total teeth  

  
  

1.  Dentition periods and succedaneous teeth 

   
   

• Humans = 2 dentition types but THREE dentition PERIODS 

  
  
  
  

  • Bc decidouus and perm periods interlap, which makes the middle mixed periods. 

    
    
  
  
  
  

1. Primary= mostly Decidious 

   
   



2. Mixed 

   
   



3. Perm 

   
   

1. Primary period 

   
   
   
   

   1. Only baby teeth 

      
      
   
   

   2. 6 mos to 6 years 

      
      
   
   

   3. At 6 years the 1st mandibular molar will erupt. = lower 1st molar = 6 year old molar 

      
      
   
   
   
   



2. Mixed dentiition period 

   
   
   
   

   1. Both baby and perm teeth 

      
      
   
   

   2. 6 years to 12 years old. 

      
      
   
   

   3. Starts at 6 years old with eruption of 6 year old molar = lower 1st molar = mandibular molar 

      
      
   
   

   4. Ends at age 12 when the last tooth efoliates / falls out = maxillary second molar = upper 12 year old moalr = second molar 

      
      
   
   
   
   



3. Permnant dentiion period 

   
   
   
   

   • Begins at 12 years old when the maxillary 2nd molar falls out of the upper arch 

     
     
   
   

   • Continues till we die basically 

     
     
   
   
   
   

• In order for a permanent tooth to erupt a baby tooth must exfoliate, or fall out. This happens through resorption, which is a natural process of the roots melting away or eating themselves  

  
  



• Succedaneous (sucks-uh-daneous) teeth = perm teeth that replace the exfoliated baby teeth  

  
  
  
  

  • Means succeeding teeth, teeth that come after the baby teeth.  

    
    
  
  

  • There are 20 since they are replacing 20 baby teeth.  

    
    
  
  

  • Inciscors, canines replace their counter parts and premolars replace baby molars. 

    
    
  
  

  • Since the PreMs are replacing the baby molars the PERMMolars have nothing to replace therefore they are NOT succedaneous teeth.