Page 148 - My FlipBook

146 DENTAL inSTOLOGY AND OPERATIVE DENTISTRY

The osteoblasts of the inenibi-aiic cover tlie siirlace of" llic l)one,
formiiiii; tlie wall of the alveolus, lyinji; between the libers which are
built into the bone. In form and function they arc like the osteoblasts
in attached portions of the periosteum. They form bone around the
ends of the peridental-membrane fibers, buildiui^ them into the sub-
stance of the bone. The bone thus formed over the wall of the
Fk;. 12S.

rd.M.

Bl.Il

H.B.

r'enetrating; fibers in bone : Pd.M, peridental membrane ; OW, osteoblasts of peridental membrane :
062, osteoblasts of medullary space; Pd.B, solid subperidental and subperiosteal bone with
imbedded fibers; il/s, medullary space formed by absorption of the solid subperidental bone
with imbedded fibers ; H.B, Haversian-system bone without fibers built around the medul-
lary space. (About 200 X.)
alveolus is like the solid subperiosteal bone, and is penetrated
throughout its thickness by the imbedded fibers ; but, as with the
subperiosteal bone, it is constantly being penetrated by perforating
canals, the solid bone being removed by absorption and rebuilt in
bone with Haversian systems. This process is shown in Fig. 127,