Kev txhim kho hniav yog txheej txheem nyuaj thiab ntev, pib thaum ntxov ntawm lub neej (tseem nyob hauv plab) thiab xaus rau hnub nyoog 18-20 xyoo. Hais txog yuav ua li cas nws mus, thiab dab tsi feature characterize nws, yog piav nyob rau hauv tsab xov xwm no.
Cov hniav yog ib qho derivative ntawm mucous daim nyias nyias ntawm lub qhov ncauj kab noj hniav ntawm lub embryo. Cov kab mob enamel tsim los ntawm nws cov epithelium. Thiab los ntawm mesenchyme nyob rau hauv nws - dentin, pulp, cement thiab periodontium nyob ib ncig ntawm cov hniav (cov ntaub mos mos thiab tawv). Nws yog ib txwm ua kom paub qhov txawv peb theem ntawm kev txhim kho:
- Txhob cov kab mob thiab cov hniav ncaj qha.
- Differentiation of primordia.
- Tooth formation.
txheej txheem yog qhov nthuav heev. Txoj kev loj hlob ntawm cov hniav pib ntawm 6-7 lub lis piam ntawm lub embryo. Nyob rau lub sijhawm no, lub epithelium ntawm qhov chaw ntawm lub qhov ncauj kab noj hniav pib thicken. Flask-shaped protrusions kuj tsim. Tom qab ntawd lawv tig mus rau hauv lub cev enamel ntawm cov mis nyuj cov hniav.
Lub lim tiam 10, mesenchyme hlob tuaj rau hauv lawv. Nws yog tus rudiment ntawm cov hniav papilla. Thaum kawg ntawm lub hli thib 3, cov kab mob enamel cais los ntawmcov ntaub ntawv. Ces lub hnab hniav pib tsim.
Lub hli peb yog qhov nquag heev ntawm kev tsim cov yam ntxwv ntawm lub cev. Nws suav rau tag nrho 2nd theem ntawm kev tsim cov hniav. Qhov thib peb pib thaum kawg ntawm lub hli 4. Nyob rau theem no, cov ntaub so ntswg twb tshwm sim: cov hniav pulp, enamel, dentin. Feem ntau, kev loj hlob ntawm cov hniav yuav siv li 5-6 lub hlis.
Qhov tseem ceeb kom paub
Cov txheej txheem saum toj no yog qhov ua tau ntau dua thiab ntau qhov txheej txheem. Nws yog ib qho tseem ceeb kom paub tias kev kho hniav maldevelopment feem ntau yog vim li cas vim li cas cov khib nyiab pov tseg tsis raug. Qhov tshwm sim tuaj yeem yog:
- Tsim cov hniav ntxiv.
- Enamel hypoplasia (kev txhim kho tsis zoo).
- Kev kho hniav tsis raug ntawm lub puab tsaig. Qhov no tseem hu ua dystopia.
- Dentin formation defects.
- Irregular shape of tib neeg cov hniav.
- Erosion pits.
- Tag nrho lossis ib nrab ntawm cov hniav, tseem hu ua edentulous.
Nws tshwm sim tias cov niam txiv noj qab haus huv tag nrho yug cov menyuam uas, thaum lawv loj hlob, muaj teeb meem nrog lawv cov hniav.
Txhawm rau txo qis, koj yuav tsum coj txoj kev noj qab haus huv (ua ntej thiab thaum cev xeeb tub). So kom txaus, tso tseg tus cwj pwm phem, thiab txhawb koj cov zaub mov nrog bran, tshuaj ntsuab, khoom noj siv mis, zaub, txiv ntseej, txiv hmab txiv ntoo, ntses thiab nqaij.
Enamel
Qhia txog kev txhim kho cov hniav, koj yuav tsum tau txiav txim siab luv luv txog lawv cov qauv. Enamel- qhov no yog lawv lub plhaub tiv thaiv, nrog rau cov ntaub so ntswg nyuaj tshaj plaws hauv tib neeg lub cev. Nws yog 97% tsim los ntawm cov tshuaj inorganic. Cov enamel yog nyias heev, ntawm qhov zom nws cov tuab tsis pub tshaj 1.5-1.6 hli, thiab ntawm lub hauv paus thiab sab ntawm cov hniav nws yog ob peb zaug nyias.
Enamel tiv thaiv dentin thiab pulp los ntawm kev cuam tshuam sab nraud ntawm cov tshuaj thiab txhua yam xwm txheej, thiab kuj los ntawm qhov kub thiab txias. Nws muaj enamel prisms thiab cov khoom hu ua interprism.
Nws yuav tsum tau muab sau tseg tias txawm tias cov enamel muaj zog, nws tseem raug rau ntau yam kev cuam tshuam sab nraud. Thiab txhua yam kev puas tsuaj dhau los ua qhov tsim nyog rau kev loj hlob ntawm caries.
Predisposing yam, tau kawg, kuj muaj. Feem ntau susceptibility rau caries yog tshwm sim los ntawm tej yam xws li:
- Cov hniav npog tsis zoo thaum lub sijhawm tawg.
- Tsis muaj pellicle rau ntawm tus hniav.
- noj zaub mov tsis zoo, cov pa roj carbon ntau hauv cov zaub mov, tsis muaj cov vitamins, proteins thiab cov khoom muaj txiaj ntsig.
- Kev ua txhaum ntawm cov qaub ncaug.
- Haus dej uas tsis muaj fluoride.
- Tsis tiav tshuaj muaj pes tsawg leeg thiab lwm yam sib txawv uas tshwm sim thaum lub sij hawm tsim cov hniav.
Hmoov tsis zoo, enamel feem ntau raug rau ntau yam cuam tshuam. Nws tuaj yeem vau, feem ntau muaj qhov tsis xws luag, qee qhov muaj kab mob abrasion.
Dentine
Lub tswv yim no twb tau hais ua ntej lawm, nyob rau hauv tus txheej txheem ntawm kev sib tham txog theem ntawm kev txhim kho hniav. Dentin nyuajntaub ntaub. Lub crown yog them nrog enamel, thiab cov hauv paus hniav yog them nrog cement.
Feem ntau dentine yog tsim los ntawm hydroxyapatite (kwv yees li 70%). Nws kuj muaj cov khoom siv organic (20%) thiab dej (10%).
Dentine yog lub hauv paus ntawm cov hniav thiab kev txhawb nqa ntawm cov enamel. Nws thickness txawv ntawm 2 mus rau 6 hli. Lub hardness yog impressive - 58.9 kgf / mm².
Nyob rau hauv lub moj khaum ntawm lub ncauj lus ntawm histology txog kev loj hlob ntawm cov hniav, nws yuav tsum tau muab sau tseg tias dentin muab faib ua hom. Tag nrho peb muaj:
- Pib. Nws yog tsim thaum lub sij hawm kev loj hlob ntawm cov ntaub so ntswg, mus txog rau thaum nws erupts.
- Secondary. Tsim thoob plaws ib tug neeg lub neej. Kev loj hlob qeeb dua. Nws yog tus cwj pwm tsis yog los ntawm qhov kev tso kawm ntawm cov hlab hniav, tab sis kuj los ntawm ntau qhov chaw erythroglobular, tsis muaj cov ntxhia pob zeb thiab cov permeability siab.
- Tertiary. Nws tseem hu ua irregular. Nws yog tsim thaum lub sij hawm npaj los yog raug mob ntawm cov hniav, nrog rau thaum lub sij hawm pathological txheej txheem (xws li caries).
Cement
Qhov no yog cov pob txha tshwj xeeb, ua tsaug rau cov hniav uas ruaj khov rau ntawm alveolus. Kwv yees li ntawm 70% ntawm cov cement muaj cov tshuaj inorganic. Nws los ntawm ob hom:
- Pib. Adheres rau dentin. Nws yog tus uas npog lub lateral nto ntawm lub hauv paus.
- pob txha. Nws npog thaj tsam ntawm bifurcation ntawm ntau cov hauv paus hniav, nrog rau apical 1/3 ntawm cov hauv paus hniav.
Cellular cement yog qhov txaus siab tshwj xeeb. Ntau precisely, nws muaj pes tsawg leeg. Cov ntaub so ntswg no yog tsim los ntawm cementoblasts, cementocytes thiab intercellularkhoom.
Nws tiv thaiv dentin los ntawm kev puas tsuaj, tsim cov cuab yeej txhawb nqa, muab txuas ntawm cov kab mob hauv lub cev, thiab tseem koom nrog cov txheej txheem kho dua tshiab.
Pulp
Nyob rau hauv lub ntsiab lus ntawm lub ntsiab lus hais txog lub sij hawm ntawm kev loj hlob ntawm cov hniav, nws yog ib qho tsim nyog los tham txog cov ntsiab lus no. Pulp yog ib qho xoob fiber ntau txuas nrog peb txheej - nruab nrab, nruab nrab thiab peripheral.
Nws cov ntshav ncig thiab innervation yog ua los ntawm venules, arterioles, lub puab tsaig ntawm lub puab tsaig thiab cov hlab ntsha ceg. Lub pulp txhawb cov txheej txheem rov ua dua tshiab, thiab tseem yog ib hom kab mob lom neeg uas tiv thaiv cov kab mob tsis zoo los ntawm kev nkag mus rau lub sijhawm los ntawm cov kab noj hniav carious.
Tsis tas li, nws cov paj hlwb tswj cov txheej txheem ntawm kev noj cov hniav thiab kev nkag siab ntawm ntau yam khaus.
Gingival txuas
Qhov no yog qhov ua kom cov hniav nyob hauv lub puab tsaig ntawm lub puab tsaig. Qhov kev sib tshuam no yog tsim los ntawm periodontium, cervical cuticle thiab stratified squamous epithelium.
Qhov no tsis yog nws txoj haujlwm nkaus xwb. Ua tsaug rau periodontal, piv txwv li, cov hniav tsis tsuas yog tuav hauv lub qhov (socket) ntawm lub puab tsaig, tab sis kuj absorbs lub siab exerted thaum zom.
Kev ua txhaum ntawm kev ncaj ncees ntawm qhov kev sib txuas no feem ntau ua rau mob thiab kis kab mob.
Hnub nyoog hloov pauv
Saum toj no, ib yam dab tsi tau hais txog kev loj hlob ntawm cov hniav mis. Thaum thawj 12-15 xyoo ntawm tus neeg lub neej, lawv tau hloov pauv los ntawm cov neeg hauv paus txawm. txiav ua ntejthawj molar, ces lub hauv paus thiab lateral incisors. Tom qab ntawd premolars nrog fangs tshwm, thiab tsuas yog tom qab 20-25 xyoo - lub thiaj li hu ua "kev txawj ntse hniav".
Raws li ib tug neeg loj hlob tuaj, muaj qee qhov kev hloov pauv hauv cov qauv thiab cov khoom sib xyaw. Qhov no tsis yog ua txhaum txoj kev loj hlob ntawm cov hniav, tab sis ib txwm tshwm sim. Enamel nrog dentin maj mam tshem tawm, cov quav hniav tshwm, qee qhov txawm tawg. Tus nqi ntawm cov organic tebchaw tam sim no nyob rau hauv muaj pes tsawg leeg yog txo. Lub permeability ntawm ob qho tib si enamel thiab dentin nrog cov cement tsis muaj zog.
Lub pulp atrophies dhau sijhawm. Yog vim li cas rau qhov no yog kev noj zaub mov tsis zoo thiab kev hloov pauv ntawm sclerotic hauv cov hlab ntsha. Kwv yees li tom qab 40-50 xyoo, lawv kuj tau kuaj pom nyob rau hauv periodontium. Tsis tas li nyob rau lub sijhawm no, collagen fibers coarsen thiab cell organelles raug txo.
Qhov tseem ceeb ntawm txoj kev noj qab haus huv
Nws yog qhov tsis sib xws, tab sis cov hniav, thaum muaj zog heev, yeej tsis yooj yim. Yog tias ib tug neeg noj tsis zoo, nws yuav cuam tshuam rau lawv tus mob sai. Peb yuav tsum nco ntsoov tias cov hniav xav tau cov vitamins, vim lawv:
- Txhim kho cov metabolism.
- Nourish the circulatory system, paj hlwb thiab pob txha nqaij.
- Txhim kho cov enamel.
Txij thaum yau, koj yuav tsum tau saib xyuas koj cov hniav. Nws yog ib qho tseem ceeb heev rau cov menyuam yaus kom noj cov tshuaj muaj txiaj ntsig hauv chav kawm. Lawv xav tau calcium rau cov hniav loj hlob, cov vitamins B rau cov pos hniav noj qab haus huv, thiab A rau cov pob txha noj qab haus huv.
Thiab tsis txhob hnov qab txog qhov tsis xis nyob. Yog tias koj cov hniav raug mob, koj yuav tsum hu rau tus kws kho hniav, thiab pibnoj cov vitamin D hnyav, nws yog qhov tsis muaj uas feem ntau ua rau caries.
Yog cov hniav ntxhib, nws txhais tau hais tias lub cev tsis muaj vitamin A. Nws kuj ua rau muaj teeb meem nrog mucous nto thiab loosening ntawm cov hniav. Cov txheej txheem ntawm salivation kuj feem ntau cuam tshuam, uas ua rau cov enamel puas.
Thiab qhov mob ntawm cov pos hniav lossis cov hniav poob yog qhov teeb meem uas ceeb tshaj plaws. Cov xwm txheej no ua ntej los ntawm qhov tsis muaj cov vitamins B thiab C, tab sis cov kab mob no tsis tuaj yeem kho tau los ntawm lawv cov kev noj haus. Ntawm no koj yuav xav tau kev pab los ntawm tus kws tshaj lij. Thiab feem ntau, nws raug pom zoo kom mus ntsib lub chaw kho hniav yam tsawg ib zaug txhua rau lub hlis rau kev tiv thaiv.
