jIN~t.... """'"ofroo(lofmMoon.melp<riunction-
~t'<UIlCion.~isa~!>etoileii theassaOo:wI of mirte',.liulion .... aoctiYation of t.... ."il~lial c~ll.
beyond t"" enamd.fOlming."'•.
J, Tl>t' Intr.=oou, Sta8~occurs w!>lm tbe rOOf forma- tion begil1s .s a r. ,ul! of the pmlif~r.tion of bofh the ep itt>.lialroof'....dlh andtheme",nchymal ti" ". ofr....
dent.>J ""pilLl andd~nlalfollicle(Fig. 7.6).
1. Tho' supraosseous SUP' begins 1N!>Im ,~ """,i"8
""'"' II'lO'ie'S omusally thftll4h , bone'or ,....<typI
and thecanne<tiwo,isswolthe aImucosa,SOlhafthe il"duô'd "",melepitl~hum ~"II""CJOW1lCOI1>M into COn,.K1 wi,h ,heOfal~1Ji'belium(Fig.7.1).AsIhis occurs, lhe l<'dnc<'d e""me1 ."ithciium or lhe crown
prolif~'.tes and forms . r"m.u...hmen f with lhe0,.1 epithelium, A fuse d, dOllhi• •pilh~lial l.ye, OWr lhe eru pting C'OWn is ,hen formed(fig, 7.8~
4. Tho'tipollhecrownl1'lters r.... oralCdVifyt.,.b....ak-
ingthrou&bthe U'I"It('torthe ~ ~p;1'ho'1ia/
<dis.nus Inakthrvustlisoct<lfIII)Iish<'dtorthecusp tip ,,",funct ionalEruptiwPt.3se
~ -
Fig.1,' ("",,",,I.ndI""""ofrNOXH...meI ...."""''''_
"" I""",oy.
126 IIDevelopment o f the T eeth ond Supportinq'c',,,,"",,""""O' _
fig.7.10Prirn<lrytOOl~.tth< endoftheeruptiveph.""!'<rm,nent,ucce,ã
SQ' inprceruptiveph."',
Changes illtiss ue, ove rlyingte et h .
Theiniti,1chongI' ",enin thetiô ue< overlyingthet""t h before er uption of the crown, is the ,,It.1'Jt ion of the (onnective tis.,,,e of thedentalfollicletoformaP<ltl'w,' y fortheeruptingtooth.Usu,llly. thisis more prominentin efllpting perman.,,, t~elh. Histologically, the coroLlal port of the deLltalfollide becomes he.,vilypopulJwdby mHnerou, monocyre' inparallelwitho>leo(I, >I<10p"r_
ti,;p'tein !:>(me "e<Of!'tionaLldfor mationofthe eruption pathway. The monncyt~ i"n ux is enh,1I1Ced by the i"cre,,,ed-,cnetionofcoloLly-stimul,tingfonor 1 recep_
rorprotein(CSF_l )~"dbythe chemotact ic"ctio n ofthe transforming growth f,let ot lletil-l (TGF-beta-I), The fut,,".erupllon pa,hwayappe,rs os <l lOneinwl,ichcon- neniveãti'$Llefillers hJvedisappeared, cellshovedegen- erated and de(re~$ed in number. blood vessels hove Decome few er, and terminolnerveSh,1ve I>ro~enup and ,Iegener,lted. These changes are probahly Ihe p.>rtial re'\lltof theloss of bloodsupplyto this<lreo,a5 well os the release of em.yrlWSth~t,lid in degrad Jtiol1of these ti"uc" Clinically,tooth eruptio n m.,ylie JccompJrlied hy discomfort or pain, irrilOhililY.andio r.1 ,Iighl tem- perature i,,("f(''''''.
cau,ing degeneration of tlte membrane. and is the begiL1ningstageof[linic~1eru l"ion(Fig.7.91.The crow n erupts furth er. andthelaleralborde"of theor,,1""loCO,", beco me the dentogingival junction (Fig,7,9 H). The reduced enomelepithelium,nowsurrounding the crow n like acuff, become s knownos the j" nct ioL1JI orattach- ment epithelium. When the lipof the(rown~PlleJr-,in theor~1 c~vity.J[)outone- half10two-third, oftheroOIS are formed (Fig.7,9A).
5.Theo["uptingtoothcont im,es tomove O<:1CluSJllyJt"
m.' ximu""rJte.Jnd therei,gr<l duolexpo, ,,,,,"fmoreof the cl;nicolCrown (Fig.7.10). OCclusalmovement i, the
"e<ullof activeeruptiorr.As the (OO(h mooe, ocduSJlly,
&r., {\"aleXi>"sure ofthe clinic<ll crown i, ,lCcuml,!i'lled Ihrough ,;ep" "tionorthe attachmenl epitheliumfrnm the crow n<lnd the ",,,,Iting "picJI-'hlftof thegingiva, Theclinic,,1crow nisthe port ofthe tooth(cootm" 1to the
~llJcll ment epit helium ) exposed inthe0,-,,1(.WilY.and differ,from the anJlomiccm wn, the part of the((l{lth covered byenamel.The pref" " ctio""1oruptiveorerup- tivepha'ei,atso ch,raner;<ed bysign;l,c'''tch""gcs in the li""e< ovel'lying the teeth,arou nd Ihe leeth, J"d lInde rlying tlie1<,<,lh.
Alvwlor
-
Gubernac" 1um
<lenti.
CI,oicaIe,own
/
fi9.7.9 (linie.1.ppe""'K. olthe(rown . J"flC'toMlor Demogi'lgwa'
.'1>cronenl j<xlction
.;ằ'hol ":" ,\ __\
f~,7.11 Development01,-",,,pl;VCp"thw,y()\",rIyin~I~ecrown ,
_ _ _ __ _ _ _ _ _ _ _ _ _ _ __ _ _ __ _' 7J<Tooth frtp lion andShedding ._ 12I
For ",,...,ful toolh ~rupl:ion. {h~", nlllô k >0""..
~iondilleOYtflyingbonycryp((f;g.7.U).which i.in .l conSlln! 5l.~of ",modeli ng.sch<'!O<llh ~rm
~n~.mdt~fola grows.nw-iorly.100"ô".lIy.Tho:'
"""pi;""proct'SS 'dn M consioo.-dI"rtofthis ....modelã
illl Jl"WIIl. (hu'ocl",'s diIT<'R1ltiar..and """"".Ipor-
tion0(th<'bonyayplownlyil>3'''''cruptilll lOOl h. Tbo:' nuptioo p"'llt,....i)I. whictl .It lirsl i<<milt illClNSt'S In di...,.;,on, Illowins..-..romtoflho>room 10m.. .....101
mllCO<ol(fis. 1,12~Alttlough ,henupOon0(ITII)§(ptr- ...._ l~ is "mil.. 10 II.., ofprimMy lC'<'Ih. (!lie ownlyi",pnm.lfYI_ II .'" ...ition.llcompliotiol'l.
Tbt('IUpliwp"thw~ofperm.1l1oCf1Ti~ .ondC\1SI>ids
i>linsu.al1O .hotcorrnpondin:z: pimo<y ~This.un shcow$.Ipronouna<I ...Lo'gt"w:'" to.KrnmmocWlC'1M .odv.lnc,,,*~.
Snlolll fordmi"" ,n I"" """neIi"'" and m""ill. ,It!' cvi- doo'nôoCtlUplion p,ubw.oy>ofth{ ,Interior I"""""neflt l<ffh. ThHe'openings.. ,he gut..m.><uLlr f""im",.•, ....
[""lid l;n8....11O I"",In"""" prima ry trella . Ild .orc 1M _.iles0(,lipgol,..molCul.lrcurds(Fig.7.1l).1M pren>ol.>rs .'" loe.,ed bcI'W't'n the loon of I"'" prinuIY moLlrs.
Root IP\.OI"plioo in pr;""'ry [ôôII p,ocO'<"ds in mud ' th.
"',,}(' manM'.S bone '='>'111;011 (Fig. 7.14). When ,1I.
rooI'.I re(ully",,,,,, be d. 1m,.lta<;hmentoflh~Wimary crownis1~'le!1<'dand !I,ecrow nis she<!.11\i'prodllC~'
. nerllpt''''' l"'ll,way for the premol. ,., MOSl rc>ots re""'b ronlpl"t~ly ; 1l1e primMy pulps deger"'ral~ oS well.[)",Ill~lh~~riod ofmixedd~l1 [ition(."ouml 6 to 11~ elf .ge).when OOIh prim' r)I "Id i>Crm<1tK'nl
~th in lhe mout h,th~ pheoo"...,n. of root rc;;orpã
lio"alldlooth forn~ll ionproc<'t'<l<ideb\I.iM(Fig.7.14~
""'""" <h.lngcs OCtllrwhilet""tll 'till O\.linraintlK'wing
rlfki~n<y,
WIlen lhe tooth ...t> Ih~ oral mlKO~lhercdllô'd
~".mel~pil1lclillmron,,,,, into ronl.>ct wilh Ih~.,.,..,.l)r- i"lmuros.l(fiI. 7_7~S,mul l .lK'OUSly., he oral ~pithrii.ll
cells.nd mlllô'd~".mriepithdial<dl.pnlIifcr.U'.nd
f\tM,inlO_ 1Dl"It\br""",(F'1S-7.15~Furt herIIIO<M'mffiIof 11K' 'ooth stn:1~.nd (ftjns me 1Dl"It\br""'" .,.,..,. lhe
<;nIWtllip[ ,'*" 7_IS~AI.this~me mums.o~omn
\lWIched b K _d I ~d blood supply10Ihtut'l.
£nJption is~p.ad...t ...- ' I ninlermiltm' .~ Thr lOOIh will""l'l "~l)r in....tioIwylOr_
timI'.MId!lwn ft1IPI4i'in.In this""'nne< .'he<lJPPII"' inCtiuuf'J ....able10m.>1u:.>djustmmts10Iht""~
"_"lents.urn",,~.._ "Will=wtsin_of
tIw<;nIWtl~PPNrinIinlhe or.oltmty~ndruntwr~.
r...ion d'he .1l~llmml ~lheliUJtt from ltoeI/'l\olmri
,u~ (Fip. 7,9 ~nd 7.10). Reanl """'...i(lns of hunwn prcrnol.l, Pnlplion moo:'.led Pnlplr." .K1Mty ocrllrri"l mooily~Iniiht. wi'h • mark<'<! Slowi"lor~ ..,tionduringlht day.
fOg,7,13Eruption~te<'"~<n[\<'e<h('J<Ib<-'mo<"'"!of...)Iing.laI '0 thepo-i...ry<""""_NoteI....tip'"' ....101...in<loo< '"'hofo<.~.
fOg.7.14N;,;r=opic:_ " " ' " '"lho rNIionofp<Wnory _ ~
-
_ ClinicalApplication .,
Eruption of tile leeth is more g" "'l ica lly ~m;n<'<l lh.n tnviron memally ,usc~pI'ihle. Only Cal-"" of leW... m.lnutn- lion.for"".mple,ca use ddayrdtrupl lo n.
Fig 7,' 5$umma,yd;iI9,.moff",i on"ndruplure01"'du<e<le",mel
ep~he'iumandmalepit"!;"mintootheruption.
Changes in usso es around teet h.
Thetissucs",oundtheteethJisoun,lergo ch.l!\geduring tooth e' \Jplion.tniti,Hy,the dent,,1foHicl~iscompo,<0 of ,leh"JI:<' cO<Hl~clive tissue, Gradllally, .s erllptive moveme nts comme nce, collJge<t r.ber, ""comepromi- nen t.extendingbetw een th~formingm,,' ,tndthe Jiveã
Ol,lt110ne surface,Thefirst noticeab le pôrioclontJI ftbt' r
b\l ndle~ ,'ppe Jr Jt tile cervical .rea of the root ~nd
extend at InJngle coron,,110 theJlveol,tI'process (Fig, 7.16A).lit thesame time, thealveolarb,,,w ofthe(rypt i5 remodeled to "ccommodate theforming root.Asthe IJrge'crown move, occlu,,'lly,[he I>one fills in to ron- form to the smallerrootdiamete r(Fig" 7.16B"ndC).As erup[ion proceed' .mhe rco llagen fiber bundle, hecom(' visible JIOllgthe forming root (Figs,7,16Band C),The area i>e<:ome, mo.... densely il'-'jlul,tted with fLbroblJsts (Fig.7.17),IIsped,1typeoffLhroblast.the myolll''''hi' .'l.
is SJid10hJVC ront," <lilecapabilities,Ithosbt'en r(' [J0rt-
~d10 bep"" entin thepedodontailig"me nt.ifpre,e nt.
themyoflbroblast could,lid intheforce need ed intooth eruption, 1111 Iif,<lm~nt cells ond fil><'", .,'" (ur",nlly helieved to beimp orta ntintheeruptiv~proce" .During eruptive moveme111$. coll.lgen formJtLo n and fiber tUl'llover arevery rapid (po" ibly24hOLlfS).veryeJrly in the eruptive process, pôrforoting ftl,ers .1tIJ,h 10 th~
ceme ntumOn theroot ,urfJceJnd10 the alveoiarbone, Somenbersreleaseosthetoothmove,.tllenreJtt,1Chto stJbHizcthe toot h.In th;, mJnner.th" ,oolh..,lJt,iii,j,,&
prOcess is performed by the same group, of ftbt'rs thrOllgh"uttoolhe,upl ion.The fibrob iJ>tsare lhe cells
activ~in for mation,111,1d"ge"er't iO<\11fcoliJgon fibe rs.
lllveolarboneremodelingiscom imlOl" d\lfi1lgemI'lion.
As lhe toothmove< ocd usa Hy, the"ivcoiar bone inn e J'-
~sinh,ãightand ch"nge,<llJpo to,lccommod'tepassage of the crown (f ig. 7.18),TI,. to<>th Cl'Owl1,JS seen ;n Figure 7.18. h.lS migrated occlusaily, whicb re,,,lts in ne wooneheingde po,iled Jround theroottoreduce the size of thecry pt. Ahove "nd J"'und the crown,osteo- c1,lStieJndosteo i>l,stlc a<lio nOCClIrs,The,e,1<ãtio",," "
(()"r<lin,ltedduring theentireeruption process,as well asthfOUgho\ltl;h~.
TootllbeIOW. . . .. .'''Mt1'labove alveolarCle,t ,lvWla,""",,I
" Bn 5 "'A ' C ''" 0
Firts-formed"bere :;:;;;;;::;mil "';,
ri<).7.16De""lopme'\l ofiWf;ooontri lfiber<andmodirKotionof,1""01,, boned"ringloolh eruption,AEa,lyfiberformil!ion.BBone(honge', Cfurll,,.,.fib.,,-do",,'opmenl.neilrocclusion. ";thfib.,,-,; morcdense..
_ _ _ _ _ _ _ _ _ _ lTooth~ruption(1flô( Shedding 129
Cha ngesIntln u,"underiytr>g tHih.
au~al"" orru,inth<'follicuUrt~undft1yi.., I,",
~pinglOOl/l.Tbo>ô' ch.lllSC'S ,... ~10 ,he ..,n
l;",,,~..nd tile fundicbane(bon~surrou ndi",- th~ "pf~
oftit<'rool~As ,hefOOlh"'''pis,,paceisprovi<k-dfur ,h.
rootto rengtl"ã,,.primarily ""c.lu,e 01 the crownmovin8
<><:clu<J.lly and lh. ;11C"~al.e in heigl" of ,h. alveolar bo<1e. O\.llllM in the (und oc I<'gio n ..~ bcli"""d to be IaQ:l'ly romJX'ft"'lOry to lilt Icngthmi"8 of dK" rool.
Puring Ihe Pf""'UpliYemd .arty...pI~pll.>ses. the 'oUi<ular rlbrobLom and fibft1; Iic'in a ~nt po~II.ã110 lhr baS<' ofIhr roo((F'",..1,19~"""" tooIh ~...
rapidly in throocur durinsJ'R"ftll'lClion,tl""'l'IionlIL,1n
¥l any Ollie',ptriod. fine bony fT"~aPPN'in ltoe fundi< ~~...They rompellSolte to.- tooth truplion .00 provi~ ",m. '"PIlOn 10 r"" ..pk..r 'i..'.... (Fig,7.19~
SomeaUlhors,I..",ribethisd, .. bony I..dd. r.The l~ddcr
~"mo,mOL~den, e". ~Il.rn.t. layer, of bone pIJ I',
"od conr'c<liw ti"'...~ !.lid down (Fig, 7,20~ "'t the
"""ofthl'p",runctio narcrupliYe ply....wtwn rhetooth comes inm Octlu<ion mow one-tlIird of the """'mel
"""",in<~ brl~CinzM(Fig.7.168l.lOd1M 1001 isi,..""oploô',/lI.thisIi",...liltbony ~ is U..JlUlly
~ ... pLJrt ~t ~ Ii",... to m.olet' ~ ror lbt' dlPY\"lopilII root lip.. Roofromp ....ion conr;nut< ror ~ ronsidt'r~bk'li_afl~rtneIttthhiM'bttn in funClioo;
Ihi, pro<... l.k",from I 10 I.Sye....inprifiJl)' t~ h
.lrld from ;l103ye.,.in ptrmaTlentI'-"'Ih.
fl.JnctionalEruptive(Posletuptive)Phil",
Tht fin.>l function>l. tr'UpoM ph>sr belins when ,~
"",h~.ldlocclusion..ondconlitlut<lor.lSIons~~.ldl
room ...onsinIhtor,",~M1y. Durin:s lhrt~rlyp/wst offhis period.lilt~I""""tJ>flXt$S'" incl't~stin htighf dncl ,heroolS con'in ....10grow.Tht l.-e,f!contin.... 10 mow ",,-chu.lly,which ;lCcom m<><l.lt~.j.lwKrowth~nd
.lIows for roof ~lo"g.ljon. Th. mo,t marktd ch.lng<'S
",'cu," o<clt"i"ni<e<,.bll,h.d, AlveolJ' bon. Mn'ity
in(l\"~""'.JndIh~printip\cnbc..of the pcriodontdllii"
~mm, ~Sf~lJli,hlhemod-vninfO",pardlt BrouPSori~","
~ ~boutfM B'''8iV.a.1ht~lvtOlar=0;(.md Tht.IW'Ol.or
<wUcI>MOUnd!he 1001-
_ O iniullApplication . ,
Amisyn:stoothmq~If intippilllof.adjooceilt
"""h irllOlhe ~ ~.,~br!hisloss.I'r~m.nu...
Ioos '"~ prim.olYlootllR'Sullinllin lh is condition nwy Pl'tWnI eruptioo or lhe ptnTWntnf tooth or cau....il1 imp.ction.
B
o
f'!l-7.11_ipalli>ô ... ' '""ilin~_ _thecJwongtin ,ho~'"IoAdefi><n.{ -D).1mm_10bunt.
P_.~=.~
- -
f"}-7.19( "0 "11""inhn<icbontdIin"ll=ptNt~
fi9-LIOform ahon01bon<laddorinlhelundk'''Jion.
(? p ~
A - ~ B ~ ~ c
-/UL ./(/J. '( VI-
1(,\ Lf
ã ~r ã ~ ~ . ~ F'
0 ' E ~
Fig.7.Jl ,om,,""noftheI""cl "'''''epllI,.I,"m, A.BPf<cruptivc_
CPrefu'K!;"n.1."'p'; ""ph,,,,. [)-FFun.:!""'" ",<Iu, ;On.
- "= . 'PeriOOonlal
,~
00_ '
fig 7.22lnueosed den,ityofporiodonlalligamentfiber<Juring~r"pt;o" ,
ThediJmeter ofthe fiberbundl~sinert. ' . from<lelic.lIe.
r. ,, "group' of m",,, to heavy,sCClI[OIy st. lJilil ed bun-
dles (fig.7.22 ). Arle ri•.>aree<IJb U,hed circumfc r"ntial- lyand longinldinalfy,with re'J""t1I" the (OOlh, intil"
cent ,,,1zoneof thepe riooo m.l lig.nW11I.Figure 7.23 is0\
pholomicl'OgL'Jphofadevelopingroot.1n<lidi~koutline.' e<1 ch orthe hl()(lJ ve."e l.,in thepUlp,as wellas in the pcriod ontdiliga meill.Th~nthe tissueiscleJJ'cdla'eveal thevessel" Ol>se Lwthenumem", w"e l> O",t~me rthe ]ig.;rne nt fmOl lI,e Jlveal'" wne. Nerve' for 'ens ing p"in,heat, (old. proprioception,,lI\d pL'essllfeo,ganizein lhe periodonlal ligament ~11,1 (ourse .,Iallgside these blood vessels.FLomapextogingivd,both myeolindle,1~nd
nonmyelin;lI.dnerve ' I',IVe rsethecenn .1,egiollofthe
Ilf,dm~mdlong wilh Ihe l'I""d vessel, (Fig,7.24).When the fOot callalnaL"fOWS,"Sa "'s\lltof rOoltiprlWLL'cilion.
Jpir"1 fil,eL'S develop to he lp (lishion tile force' of on']"S<ll imp-let (Fig. 7.22 ). Loter In life,attrillon indY weardowntheo( dll,,, 1'u, f,lee,ofIIlC teeth(Fig,7,21). TIleteetherupt slightlyto [Oo'pe,,,,,te for I "" of tOOlh structure Jnd to pLCvent OCdU'dlove n-Io,,,,,,(Fig.72S).
If theocdus<']we.'r i-'excessive.cementum isdeposited on the"pkallilird oflheroot(Fig.7.25) ;iti.,dep'1Site d in tl,e fu,calionLegionofmo)"", to compen"llefor hype"''''I'ã
ti011 ofthe.,e teeth. Somewneap PDsitionOCClIrs "t the alveolar nests,111"dditi"n 10 ,Iig]l locclu" lmove me l1l, lho teeth tendto move anteriorly.Thi, is 'errll"d nlesi,,]
drift,\nd resultsinwneresorption onthe me,i,,1 wall"f the",..ket' .;r,,1bone.'pll<1<irioLlonthe dist,,1wail.
Theories of Tooth Eruption
Manyf"n ors rd ue,]to ,oo,h eruplion hJve been stlld- led.and ,e,walappe"rto b. import," " to liteerul'tive pm( e\<.ItW,l<OL1cethoughtthatrootgrowthand p"lp,,1 press"",wer\,f"",I.llnent~1 belo!'" lIntiicase,of~rup
tion of rootless teeth were reported.The ide,l thJt IIle fundicbDne Jrea and wnyiadde r formationwe,-eC"' ,-
Blood ,
"" . ..,,. /'
inpe'iOOonlai liga 'l'<'m
- - ,, "
fig.7,23V.",,,I.f;'''tiQnofpulp,n<!periodontal;\I''''h'''~'dUringtooth erupt.",.
fig.7.24Ultr" t,",I,,",01j"t"" tili, 1'I"'" j"p,-,r;odo"tall;~a.
mont"Ion~with nerves,ndblood ,.""" ,,
fig.7,27 1I\(,.-.", ;n ,ellactivityiOp<'I'kldOrlfollg.a"""tduring~r"l'lion.
f;g.715P!Netupr....~...WiM _ compen;ol;,o,~ol
...
--
_ _,,",, " " ' 01
....,...,lM1Ofy-
[\
'\ "
'. \ f- Tl1l<:U<>od<:IImOn"'n
fill,7.U '0'11,~ng""" rrh.()IJt~r"""".... <pithelium miwoteiolOl~luNIã
d...><1,idiOperiodo""rd'-"'l'1opmt'n l ..><Ie,,'ptioo01the100111, elO w.lSdi...n'ed ~, ...u...mm.. 0( me eruption
I"'lh....~and ,heliming 01jl<lppelrlnce...lled tlw, ,hew loKI"'"l ...morelikriy10~a ft'SU1t.r~lherItwl l c...~ol.""""ion. VlSCUllrilyIwsIontbemron<iderf<l lOpliyl . .in toolheruprion. for rum11k'..."0.01 lilt S)'lllp.alhotic "'""" CO"'" \Il$Odilllioolnd ft'SU1t>
in eoOl1onnuplion ollfttlL Louliled ~... l
muI,01periocIontitis, llsoCl ...i~.lSedv;ằCU\.arily 01pt'riodO","I,i""'>eS<>Ad increlW ertlpl ion olldjlcenl teelh. OIher loKI<>n.suchis hypopillJi'~ri'm.deere"", vlSCullri'y~nd ~Iso~lrderupilOn.
[)oo(n..w pr=u ....overIyil1l .I lOOlh .nd iocr~.lSed
pressure~roundaDdunderi,l ....nu,iorf.>ctonin tOOlh mlpfion. FiT51. the nuprion pathway Jlesjns develop-
",em when ItIOl [onn.llion COIT1mencPS (Fig. 1.26). In CoK1._.II i~lOnhive """""malthispalhway wi • ...Iop '"""'"whmthe toolhis I'I'IfIdIaniully pR'-
_, edfromnuplioon.Sônnd.iHl... I,III oltissue:s surã
roundi"ll!ltr=bocnJf$durir1;ll boIhpmUll('lion.lJaDd functi<lnoal nupliveperiods.Iu,litperiodontalfi~t
rtbers Incre_ in num her~ndrna.... posilion.thea~ã
olarboneremod el. lnd 'hu s liml15thesort-tis' '''~ amund tl>c t""tb. III tb~ "'me lime. tilt perindnntal filnnbl.l.1Sprollfcrat~and tbev~S(ul.lrsupply incrl''''''' IFig. 7.71).Alllbe.. change, bring.1>0,"in<T~a~ pres-
,u,"~ro"ndami "nde r the ",uprlng,....,b ,
8iochtmic~1 ~nalysts ...alnl ,Iw, {he dental follicle reac!lts If!, 1Ildximum _ ight it the ,ime fiUpi ion bog",•• Collagen ron"'''' incn'a'C, by2$:1:~nd prote<>- g.Iyo:lns by 45:1: duri ng eruplion,Transf<>rming growth f""oreeu I(TGF.be ta I)isa me",be rofa proteinfamiã
Iy wi,lidiv<-r.. biologic .lCtivitie., wl,ie h,limu iatesth~
fib mhl," 1of the dentalfollicletos ecretea11eXl racd iuiar ma, rlx" " "d " ,1for it sdcv~lo Dn",,,' inloai>Cridont al lig.
llllC'll.To d."',the role<>ftl>cel'lM rmal ~rowlhlactor lECF) duri ngerupt ion i, not cl~ar. It is, h",V<.'V~r. ",id th.lri, shmulatesth~ diff~....ntill ionof peri<>d"" tal liga- menlfibmbl~st'_
Impo,u""o ll1e di"",,,ioonofCl Use'S ol'OOlheruption i. ,he'OOIh~, lhecap and bell,'a~e. I,h.l. been ,hown
, l\,l, folli,'ul."cellsmigratelrom ""ar the .urf"". oflhe ."amd orga n, .,"d dental I'-'pill"e 10 give rise to the ,e ment " m, periodont.ll ligame nt, an~ .,Ivenla,- bone,
1lr".H "~ lI,e,", cells .fleel [lw resorpt;un of bone in
ôceeeô grow,h and bodiiy n",,,,,ment of lh~ I.elh, Ihey proba bly pl.lyl role in 'OOlh eru ptio n.TheS<"celi.
tnolycauseenzymaticdege,l<'1"alion of,heIi" "", overly- in. ,he teethandmay rontribu ,e'0 mef,,""" tio n ollis- suessurroundingand undtrtyill.l ' he ln1h.Rn:entstudã in ..<>diesha\oeshownthedetlUlIfollicleto!II'ofprime
;mpn'uoce in looth ertlplion.Jtemoyalof,heden....101-
lio:~u ...= ...tion oferupfion.TJw mainrole oflilt
dm.... JoIIide in 1000h ertlpfionis,hefnrmationofthe ertlplionpathw~llle...0(lilt.IdƠ~_ h .TJwlnlã
IidellsopooWks!be0SInIbIlSts'Mtonn,""bonetra_
becuIat*a1lO ,he lOOth. Abo, thewr¥eIll<alltaU piaôa,PRri>c'{iJD0,"5 duri..., lOOlh ertlplinR.