Question

In the mandibular dental arch of a 12-year old boy,

the permanent first molars are in contact with the
first premolars and the crowns of the second
premolars have erupted lingually. The likely cause
is
A. ankylosis of the mandibular second premolars.
B. lack of space.
C. teeth too large for the dental arch.
D. premature loss of deciduous second molars.
E. faulty lingual eruption of the second premolars.

Answer 1

The likely cause of the first permanent molars in contact with the first premolars and lingual eruption of the second premolars in a 12-year old boy's mandibular dental arch is lack of space.

Step-by-step explanation:

In the scenario described, where the permanent first molars are in contact with the first premolars and the crowns of the second premolars have erupted lingually in a 12-year-old boy, the likely cause is B. lack of space. During middle childhood, the mouth undergoes significant changes, with the loss of deciduous teeth and the emergence of permanent teeth. The mandibular arch must have enough room to accommodate the new teeth, and if not properly managed, issues such as the one described can occur.

The mandibular second premolar typically erupts after the loss of the deciduous second molars, which occurs on average from 24 to 32 months. By the age of 12, the first and second permanent molars would have emerged. Since the permanent first molars are already in contact with the first premolars, it indicates that there could have been insufficient space for the second premolars to emerge properly, causing them to come in lingually instead of in their correct position.