One-on-One An Interview with Dr. Paul Homoly Simply Beautiful A ...

In the normal osseous crest, the
“
facial margin of the preparation
should be 2 mm to 2.5 mm
coronal to the osseous crest,
or 0.5 mm to 1 mm apical to
the free gingival margin.
”
surements, which should be of the entire dentogingival
complex, will be the guide for placing the finish line of
the preparation.
Ideally, for anterior teeth, the facial measurement should
be approximately 3 mm, and the interproximal measurement,
when adjacent teeth are present, approximately
4 mm. This relationship is considered a normal crest 6
and exists on the facial and interproximal surfaces of
normal sized teeth in about 85 percent of patients (Figure
2). With this gingival-to-osseous crest relationship, if
the tissue is traumatized with any type of clinical procedure,
it will heal in a similar fashion. 7 The healing will
return to normal 85 percent of the time. 8
If the depth of the osseous crest to the gingival margin
is greater than 3 mm facially and 4 mm interproximally,
it is considered a low crest and exists on the facial and
interproximal surfaces of normal sized teeth in about
13 percent of patients. The low osseous crest and thin
tissue biotype pose the most variation for final gingival
position. 9 Black holes and recession are most likely with
this situation. If the gingival depth to the osseous crest
is less than 3 mm facially and 4 mm interproximally, the
osseous architecture is considered a high crest and exists
in about 2 percent of patients. High crests are most
susceptible to biologic width violations.
Figure 4: Normal crest 3 mm on facial.
Tissue biotype affects the stability of the tissue in all
levels of osseous architecture. Thick biotype reduces
the risk of recession and black holes. Thick biotype and
a low osseous crest will yield pocket depth formation.
■ Preparation Finish Line to the Osseous Crest
In the normal osseous crest, the facial margin of the
preparation should be 2 mm to 2.5 mm coronal to the
osseous crest, or 0.5 mm to 1 mm apical to the free
gingival margin. The interproximal margin of the preparation
should be located 3 mm coronal to the osseous
crest or 1 mm apical to the interproximal papilla. In
this relationship, how the gingiva will reestablish itself
to create an intracrevicular finish line can be predicted
after the impression.
Figure 5: Normal crest 4 mm on interproximal.
With low crests, the facial margin of the preparation
should be a minimum of 2 mm from the osseous crest,
and the interproximal margin more than 1 mm away.
With high crests, the facial and interproximal margin
of the preparation should be at the level of the free
gingival margin or no deeper than 0.5 mm. A high crest
is most susceptible to biologic width violations. If the
margin of the preparation is deeper than 0.5 mm, the
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