Sentence:  The <WSD>gap-toothed</WSD> grins of many 7- and 8-year-olds reflect the rapid loss of baby teeth and eruption of permanent teeth during the early school years, although children typically do not lose all of their primary teeth until they are about 12 years old. 
Meaning of the word marked with <WSD> tags:  exhibiting a gap where a tooth is missing, as of a child who has lost a baby tooth, or an adult who has lost a permanent tooth