Autogenous and Allogeneic Bone Grafts in Periodontal Therapy

tide size of approximately 250 to 800
Particle sizes within this range have been
shown to promote osteogenesis, whereas a
particle size below 125 |xm induces a macrophage
response (Mellonig and Levey,
1984).
5. The graft is again immersed in ethanol.
6. The bone may or may not be dimineralized.
7. The allograft is freeze dried. Freeze drying
permits long-term storage and reduces antigenicity
(Turner and Mellonig, 1981;
Quattlebaum et al, 1988).
VII. GUIDED TISSUE REGENERATION
AND BONE GRAFTS
Case reports and controlled clinical trials have
indicated that the placement of a physical barrier
between the gingival flap and the root surface
enhances the potential for wound healing (Nyman
et al, 1982; Becker et al, 1987 and 1988; Pontoriero
et al, 1988 and 1989; Lekovic et al,
1989; Caffesse et al, 1990; Gager and Schultz,
1991). This procedure retards apical migration
of epithelium, excludes gingival connective tissue
cells from the wound, and favors healing
from the periodontal ligament cells (Gottlow et
al., 1986). The histologic result is new attachment
(Gottlow et al, 1986; Becker et al, 1987;
Nyman et al, 1987).
A recent study indicates that the periodontal
ligament cells migrate only a short distance and,
at the same rate, with and without the placement
of a physical barrier (Aukhil and Iglhaut, 1988).
Therefore, the critical role of a physical barrier
may be that of space creation to allow migrating
cells sufficient time to undergo amplifying cell
division and populate the root surface (Aukhil et
al., 1990). In addition, cells from the bone may
play a role in guided tissue regeneration. Cells
from the endosteal spaces of alveolar bone can
synthesize cementumlike tissue and may migrate
from bone into the periodontal ligament (Melcher
etal, 1986).
A number of case reports suggest that the
combination of an osseous graft and the physical
barrier enhances bone fill and promotes more
favorable results (Schallhorn and McClain, 1988).
Anderegg et al (1991) compared 15 pairs of
furcation defects in 15 patients treated by DFDBA
plus an expanded polytetrafluoroethylene (Gore-
Tex Periodontal Material, W. L. Gore & Associates,
Flagstaff, AZ) physical barrier or by a
physical barrier alone. They found both horizontal
and vertical bone fill to be more favorable
with the use of the graft plus barrier. However,
Garrett et al. (1988), using a graft of DFDBA
and dura mater sheets between the replaced surgical
flaps and the tooth surfaces, found limited
improvement of the treated defects over pretreatment
levels. Stahl and Froum (1991) have most
recently shown cementogenesis on teeth treated
by osseous allograft and an expanded polytetrafluoroethylene
membrane. Osseous remodeling
and crestal osteogenesis were seen in association
with cementogenesis. New attachment was histologically
present within two of four calculus
notches in this sample.
VIII. FUTURE DIRECTIONS
Although bone grafts have been shown to be
efficacious for the treatment of periodontal osseous
lesions, the reconstruction appears to be
limited to a mean bone fill of approximately 3.0
mm irrespective of the type of bone graft material
(Table 1). Because the ultimate goal of periodontal
therapy is to reverse the disease process
and completely regenerate the periodontium, additional
stimuli to enhance the regenerative process
clearly are needed. Polypeptide growth factors,
a potent class of natural biologic response
modifiers, may be the answer. Factors such as
osteogenin (Bowers and Reddi, 1991) or the combination
of platelet-derived growth factor (PDGF)
and insulinlike growth factor (IGF) (Lynch et al,
1989) may have potential. Other growth factors
such as transforming growth factor- (3 and basic
fibroblast growth factor may also have a place
(Graves and Cochran, 1990). However, the use
of growth factors (GFs) to augment periodontal
regeneration also poses many questions, such as
1. What is the proper dose of GFs?
2. What is the best biologic carrier for the GF?
3. When should the GF be released into the
healing cascade?
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