Image Based Question-65878

Correct Answer » C Explanation

Ans: C. 20

Number of teeth and the timings of their eruption

• The first human teeth to appear, the deciduous (primary) teeth (also known as baby or milk teeth), erupt into the mouth from around 6 months until 2 years of age, in a process known as “teething”.
• Usually, the first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars.

Teething age of primary teeth:

• Central incisors : 6–12 months
• Lateral incisors : 9–16 months
• First molars : 13–19 months
• Canine teeth : 16–23 months
• Second molars : 22–33 months
• There is one in each quadrant, making a total of four of each tooth – total 20 primary teeth

The dentition goes through three stages.

• The first, known as primary dentition stage, occurs when only primary teeth are visible.
• Mixed dentition stage starts when the first permanent molar appears in the mouth, usually at five or six years, and lasts until the last primary tooth is lost, usually at ten, eleven, or twelve years.
• After the last primary tooth is shed or exfoliates out of the mouth, the teeth are in the permanent dentition stage.

There are 32 permanent teeth.

• Maxillary teeth typically erupt in the following order: (1) first molar (2) central incisor, (3) lateral incisor, (4) first premolar, (5) second premolar, (6) canine, (7) second molar, and (8) third molar.
• Mandibular teeth typically erupt in the following order: (1) first molar (2) central incisor, (3) lateral incisor, (4) canine, (5) first premolar, (6) second premolar, (7) second molar, and (8) third molar
• Most children have 28 of their permanent teeth by age 13 years.
  • These include four central incisors,four lateral incisors, eight premolars, four canines and eight molars.
• The last of the permanent teeth to appear are called “third molars,” or “wisdom teeth.”
  • They usually begin to erupt between ages 17 and 21 years.