上齿龈

upper alveolar ridge

used in 上聲|上声[shang3 sheng1]

(bound form) up; upper; above; previous / first (of multiple parts) / to climb; to get onto; to go up / to attend (class or university) / (directional complement) up / (noun suffix) on; above

upper teeth

tooth / CL:顆|颗[ke1]

gum / gingiva

variant of 啃[ken3]

gums (of the teeth)