Which of the following conditions is NOT typically associated with periodontal destruction in primary teeth?

Steven Johnson's syndrome is primarily a severe reaction to medications or infections that leads to skin and mucosal membrane damage, rather than a direct condition that affects periodontal health. While it can lead to various systemic issues and potential oral manifestations, it is not specifically linked to periodontal destruction in primary teeth.

In contrast, the other conditions listed are associated with periodontal destruction. Down's syndrome is known to involve various oral health issues and an increased prevalence of periodontal disease due to factors like altered immune response and poor oral hygiene practices. Hypophosphatasia affects the development of teeth and bones and can lead to early loss of primary teeth and periodontal complications. Cyclic neutropenia, characterized by periodic decreases in neutrophil levels, can lead to increased susceptibility to infections, including periodontal disease.

Thus, the unique pathology and implications of Steven Johnson's syndrome differentiate it from the other listed conditions, making it the condition that is not typically associated with periodontal destruction in primary teeth.