Which of these can be considered an outcome of poor oral hygiene?

The development of dental caries is a primary outcome of poor oral hygiene. When oral hygiene practices are neglected, plaque— a sticky film of bacteria— accumulates on the teeth. This plaque can lead to the demineralization of tooth enamel and, over time, create cavities. The bacteria in plaque produce acids that erode the tooth surface, leading to caries. Maintaining good oral hygiene is essential to prevent this process, as regular brushing and flossing effectively remove plaque, preventing it from hardening into tartar and causing further dental issues.

In contrast, promoting healthy gums, strengthening tooth enamel, and reducing plaque buildup are direct benefits of good oral hygiene practices. These outcomes are the opposite of what occurs when proper care is not taken, clearly illustrating why the development of dental caries, as a direct consequence of poor oral hygiene, is the correct answer.