Final answer:
Beyond the age of 5 years, thumb and finger sucking can affect the upper facial structure and anterior teeth, leading to potential orthodontic issues.
Step-by-step explanation:
The correct answer to the question about the age at which thumb and finger sucking might affect the upper facial structure and upper anterior teeth is option C. 5. Beyond the age of 5 years, persistent thumb and finger sucking can negatively influence the growth and alignment of these teeth and facial structures. It's important for children to cease this habit before reaching this critical age to prevent potential orthodontic issues.
During early childhood, the primary or deciduous teeth have erupted, and by age 6, permanent teeth start to replace them. The facial structure and dentition are both still developing, which makes them malleable to outside forces. Continued thumb sucking past the age of 5 can cause problems such as misalignment of the teeth, overbites, and changes in the roof of the mouth. For this reason, dentists and pediatricians often encourage strategies to help children stop this habit by this age.