Postnatal Growth and Development

Postnatal growth and development  Yenny Yustisia Dept. Of Oral Biology  Dentistry UNEJ

MODES OF GROWTH • Basic concept of bone growth: bone can only change at its surface • Two o!es of growth: " #eo!elling " !isplaceent

Remodelling • cobination of apposition an! resorption$ which can siultaneously occur on both en!osteal an! periosteal surfaces. %t aintains the for of a  bone an! pro&i!es for its its enlargeent • 'unction: (rea relocation

%n the face$ areas that are part of one structure soeties get relocate! an!  becoe part of another another structure. E)aple: E)aple: *rowth of an!ible +rocesses of area relocation perit eruption of ,n! olars at age -, an! r! olars at age -/0,1

Displacement • %n&ol&es o&eent of the whole bone • Occurs at suture lines. (ount of enlargeent e2uals e)tent of !isplaceent • +riary !isplaceent: !isplaceent: process of physical o&eent relate! to a bone3s own enlargeent • 4econ!ary !isplaceent: !isplaceent: one bone !isplaces another bone as the first bone is o&e!: the  &isible effect is result of a growth e&ent e&ent that happene! in another place

• The face is continually reo!ele! an! !isplace!. %t changes as it grows out fro un!er the brain • Displaceent ust occur first an! then reo!eling will ta5e place as bone grows g rows

WAYS TO STUDY GROWTH • %plants 6B7or53s stu!ies8 •  9ital !ye ar5ers ar5ers • 4uperiposition of hea!fil tracings

calvaria • %ntraebranous %ntraebranous osteogenesis begins at !iscrete centres that subse2uently !e&elop into the coponent cal&arial bones • Their growth entirely results fro periosteal acti&ity at the bone surfaces$ augente! by eso!eral !e&elopent at the inter&ening sutures an! fontanelles

• 4eparation of these flat cranial bones at birth by sutures an! fontanelles principally ser&es to: "  facilitate ol!ing of the relati&ely large neurocraniu at parturition " accoo!ate brain growth an! intracranial flui! e)pansion$ i.e. 4utures an! fontanelles ha&e little inherent growth potential of their own.

•  (fter birth$ intraebranous intraebranous osteogenesis osteogenesis along the e!ges of the fontenelles eliinates these ;open3 spaces fairly 2uic5ly$ although the a!7acent bones reain separate! by thin periosteal0line! sutures for any years • They fuse se2uentially !uring a!ulthoo!: a feature with iportant forensic connotations. connotations.

• intraebranous intraebranous osteogenesis at the sutures su tures is a a7or echanis for cal&arial growth • hanges in si