Lub maxillary thib ob premolar yog ib ntawm ob cov hniav nyob nyob rau hauv lub puab tsaig sab sauv, tom qab (tawm ntawm nruab nrab ntawm lub ntsej muag) los ntawm ob lub maxillary thawj premolars ntawm lub qhov ncauj tab sis mesial (mus rau midline ntawm lub ntsej muag) los ntawm ob qho tib si maxillary thawj molars.
Tus lej twg yog tus thib ob premolar?
Number 13: 2nd Bicuspid lossis 2nd premolar. Number 14: 1st Molar.
Koj puas muaj 2 lub premolars?
Cov premolars, tseem hu ua cov hniav premolar, lossis bicuspids, yog cov hniav hloov pauv nyob nruab nrab ntawm cov hniav thiab cov hniav. Hauv tib neeg, muaj ob premolars ib quadrant nyob rau hauv cov txheej txheem tas mus li, ua rau yim premolars tag nrho hauv lub qhov ncauj. Lawv muaj tsawg kawg yog ob cusps.
Puas muaj pes tsawg kwj dej ua 2nd premolars?
Maxillary thib ob premolar feem ntau suav hais tias muaj ib cag thiab ib tus kwj dej [2, 3, 6, 14].
Dab tsi yog qhov ua haujlwm ntawm ob premolars?
Qhov kev ua haujlwm ntawm qhov premolar no yog pab tus mandibular thawj molar thaum lub sijhawm mastication, feem ntau hu ua zom. Mandibular thib ob premolars muaj peb cusps. Muaj ib lub cusp loj nyob rau sab buccal (ze rau sab plhu) ntawm tus hniav.
