Service life of retainer

Feem ntau, nws yog hais txog ob xyoos, thiab nws txawv ntawm ib tus neeg mus rau lwm tus. Qee tus neeg mob yuav tsum tau khaws cia rau lub sijhawm luv dua, thaum qee qhov mob uas yooj yim rau rov qab los, xws li cov hniav torsion hnyav thiab qhov chaw ntawm cov hniav, nws xav tau lub sijhawm khaws cia ntev dua, lossis txawm tias khaws cia mus ib txhis. xyoo rau cov ntaub so ntswg nyob ib ncig ntawm cov hniav kom zoo thiab ruaj khov. Thawj peb lub hlis tom qab kev kho mob tshwj xeeb tshaj yog nws yuav rov zoo dua Nyob rau thawj xyoo tom qab tshem tawm cov cuab yeej, tus tuav yuav tsum tau hnav kom zoo thaum nruab hnub thiab hmo ntuj. Tom qab ntawd, tus tuav tau hnav thaum hmo ntuj rau 6 lub hlis. Yog tias koj hnav tau yooj yim, koj tuaj yeem txo lub sijhawm hnav ntawm tus tuav: ib hmos txhua hnub, ib hmos hauv ib lub lis piam kom txog thaum koj tsis hnav nws.