Pacific Coast Society of Orthodontists Bulletin Summer 2023 - 67

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that is bonded at three points to prevent torquing
during mastication.
Dental Factors Can Alter Graft Outcomes
A biological rationale for the one-half-two-thirds
root formation rule is to ensure that the developing
tooth is encased in bone before the bone
graft. Ideally, bone is grafted to bone, not to dental
enamel or cementum. If part of a dental root
or crown emerges out of the bone adjacent to
the cleft site, then grafted bone might not bridge
in these areas and leave a void or porosity in the
grafted bone.11,12
the segments above or below the emerging
tooth11,12
(Figure 4). A plan has to be developed
to cope with these potential problems. In some
cases, teeth may need to be extracted in the cleft
site. In young patients, the graft can be done earlier,
before eruption of the graft-adjacent teeth that
are poised to erupt into the cleft space.
Figure 4. (A) Pregraft cone-beam computed tomography.
A 5 × 5-cm cone-beam computed tomography
image showing primary teeth that need to be
extracted prior to grafting. Although the canine root
is less than 1/2 formed, the root of the rotated central
incisor and the crown of the canine are on the cleft
margins and could dehisce and create unfavorable
conditions for grafting. An earlier bone graft could
have ensured that these teeth would be surrounded
by bone and have optimal periodontal outcomes.
(B) An example of a graft outcome showing bony
void around an emerging canine crown with bony
bridging apical to the crown
result in infected autogenous bone grafts that will
need debridement and regrafting (Figure 4).
Primary Tooth Eruption
If the primary tooth erupts in the palate away from
the cleft site, then it could be preserved and moved
into the grafted cleft site. The primary tooth can be
moved into the graft to maintain bone height. As a
temporary restoration, the primary tooth or microdont
can be incorporated into a Maryland bridge
Bridging Versus Complete Bone Fill
The question of whether to regraft or not depends
on the amount of bone in the cleft site and on the
position of the bony bridge. If there is a thin plate
of bone with adequate vertical height in front of
the erupting tooth, then there may be enough
bone for the canine or incisor to erupt into. As the
developing tooth erupts, the follicle will widen the
graft, allowing new bone to fill the cleft site as the
tooth erupts into the bone graft. This is an optimal
outcome. Figure 3 illustrates that a canine can erupt
into thin bone grafts and bring bone with it as the
follicle expands the bone width during eruption.
Expansion Versus Constriction of the
Arch Form
On one hand, expansion is usually needed when
the cleft segments collapse into the void of the
cleft in order to regain arch form. On the other
hand, if the cleft is unusually wide, expansion
may increase the cleft space that needs grafting.
With large alveolar clefts, segmental constriction
can help make the graft more manageable
during grafting. In our clinic, we use this strategy
whenever a patient with a bilateral cleft lip and
palate is missing the premaxilla. In a recent study,
it appeared that cleft volume rather than a critical
size distance was correlated with graft failure; the
larger the volume of the cleft space, the poorer
In this case, the graft may bridge
Summer 2023 PCSO Bulletin
67
Pacific Coast Society of Orthodontists Bulletin Summer 2023

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