What does the saying mean he stood there with his mouth full of teeth?

The saying "he stood there with his mouth full of teeth" typically implies that someone is smiling or grinning widely, perhaps in a way that suggests they are pleased, smug, or overly confident. It can convey a sense of mockery or amusement at someone's expense. The imagery emphasizes the exaggerated nature of the smile, suggesting a lack of sincerity or depth behind it.