Some have suggested「stop movement」when「rice grains」are in「cavity」of the mouth, since one's TEETH may crack or break if such hard objects are chewed…but not too many folks would attempt eating uncooked rice grains, unless starving. Glyph depicts what effectively「ceases the movement within, stops jism splats coming in cavity」of the mouth as TEETH. Original glyph is also simply「stop array of rods of people from following into your cavities」(齒) by using one's TEETH naturally…possible advice for any girl, or boy: TEETH can be used TO WEAKEN the will of someone contemplating the performance of forced fellatio, but be apprised that there may be some repercussions and concussions.
　Perhaps provides another reason for the popularity of the「foot-dis-integrating procedure」(top element) in addition to preventing the little girls from escaping, which is to prevent the little girls from clenching down and biting while forcing her to perform with a tonguing mouth.「Foot-dis-integrating procedure」was a way to obviate the need of inserting anything between TEETH in the first place (always a high-risk action) when other orifices are not yet available for any reason:
　「Qing Dynasty sex manuals listed 48 different ways of playing with women's bound feet.」
　　[　https://en.wikipedia.org/wiki/Foot_binding 2012-12-17　]　
　CLENCHING and related problems and fears are present in these glyphs:
　歯 and 齒 as teeth.
　恨 regret, hate, resentment, rueful, hold a grudge, malice, bitter feeling, rancor, to curse and swear.
　艮 chewing.
　仡 being fed up with conditions and bravely doing something about it while unafraid of the consequences.
　旡 suddenly choking on something in one's throat.
　兂 clasped with teeth.
　邪 wickedly demonic.
　拑 pinning with clenched teeth.
　音 loud noise.
　既 and 既 too late, happened already, unchangeable.
　茱 and 萸 bloody stump, dogwood.
　飢 ravenously chomping meat.
　啗 enticing lure, gnawing meat.
　啖 threaten a superior, taunt and torment, reckless endangerment while tasting and eating.
　猖 ferocious and insane, mad, reckless, not following the rules.
　惕 healthy respect of danger.
　𣇄 and 晣 biting off a chunk, bent by tonguing mouth.
　惮 and 憚 fear, dread, shirking, shrunk.
　喫 clenching with gasps.
　吃 and 喫 extirpate, destroy utterly.
　揕 bare-fisted jab, punch in the face.
　意 long in thought, intent, concerns.
　貇 tenaciously clenching jaw and not letting go.
　虞 horror, terror, terrorism.
　鉗 clamp and gag.
　𪗱 and 齟 discord, broken teeth.
　𪘚 and 齬 gritting one's teeth, great hatred.
　齭 pain caused by teeth.

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Chinese: Japanese variant of 齒|齿
Japanese: tooth, plaque, gums, teethridge, impatient, tantalized, tantalised, irritated, chagrined, chagrinned, vexed, involuntary nocturnal grinding, bruxism, grinding one's teeth out of anger or vexation, feel of food while being chewed
Unihan extended: teeth; gears, cogs; age
EDRDG: tooth; cog