牙周病

• 牙(fang; tusk)ASSOCIATIVE

The character 牙 is a drawing of fangs biting tightly together.

• 冂(surround; border)RADICAL
• 土(earth; soil; ground)ASSOCIATIVE
• 口(mouth; door)ASSOCIATIVE

A territory surrounded by boundaries like earth and gates enclosed all around.

• 疒(illness; patient in bed)RADICAL
• 丙(third heavenly stem)PHONETIC

A person lying on a sickbed crying out in pain everywhere sounds like "bing."