Quality Resource Guide
l
Diagnosing and Managing the Cracked Tooth Part One 2nd Edition
2
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Description of COF
Crown-originating
fractures
(COF)
occur
spontaneously, originate in the tooth crown, and
progress in an apical direction in the roots. In
contrast to VRF, they are not related to previous
root canal treatment. The fractures are progressive
in nature and propagate from a coronal origin into
the root, and may continue down the root apically
or toward the root surface, the latter resulting in
cuspal fractures (
Figure 1
). The end result, if no
treatment is rendered, will either be a split tooth or
a cuspal fracture.
In the latter situation, the pulp
may or may not be directly exposed.
If a cuspal
fracture does not create a periodontal problem,
the crown may usually be restored satisfactorily.
Teeth most commonly affected with a COF are
maxillary premolars and molars.
3
Teeth with COF
typically have vital pulps and pain originating in
the pulps result in unusual pain patterns making
diagnosis difficult.
4
COFs most often occur in a
mesio-distal direction (
Figure 2
), though they can
occur in a facial-lingual direction (
Figure 3
), and,
in some cases, in a combination of both directions.
Presence or absence of coronal restorations does
not seem to be a determinant factor; COF is
observed in teeth with carious, restored or intact
crowns. One might intuitively expect teeth with
restorations to be more prone to a COF than those
without. The available evidence, however, is not
conclusive, though one might assume that the
type of restoration in a tooth plays a role.
5
The origin of COF is usually in one (
Figure 4
),
or both, of the marginal ridges (
Figure 5
) if the
fracture is in a mesio-distal direction. The origin
of a COF is typically between the cusps if it
Introduction
The term ‘cracked tooth’ has been used to describe
many types of fractures and cracks in teeth.
Other terms have also been used (
Table 1
) for
this dental problem, indicating that dentistry has
not previously been able to develop a generally
accepted categorization scheme. Efforts have been
made over the years.
1
Recently a proposal to use
the term ‘Dental Fractures’ as the umbrella term
for all fractures of teeth was published.
2
Under this
term dental fractures are categorized into: (1) crown-
originating fractures (COF); (2) vertical root fractures
(VRF), and; (3) trauma-related fractures (
Table 2
).
The latter fracture category is distinctly related
to acute dental trauma and frequently includes
horizontal root fractures. This Quality Resource
Guide (QRG) will focus on the first type of fracture,
the COF. A follow-up QRG will discuss VRF.
Table 1 - Terms Used for Dental Fractures
•
Cracked tooth
•
Cracked tooth syndrome
•
Green stick fracture
•
Cuspal fracture odontalgia
•
Vertical root fractures
•
Tooth infractions
•
Craze lines
•
Split tooth
•
Fractured cusp
•
Hair-line fractures
•
Incomplete tooth fractures
•
Crown-root fractures
•
Longitudinal tooth fractures
Table 2 - Dental Fractures
Categories
Characteristics
Crown-originating fracture (COF)
Spontaneous fracture originating in the crown and
progressing into the root in an apical direction.
Vertical root fracture (VRF)
A root-originating fracture that may begin anywhere in the
root; it occurs primarily in endodontically treated teeth.
Trauma-related fracture
Tooth fracture of acute nature that may involve the crown
or the root or both and are often horizontal fractures.
Figure 1
COF originates in the crown and
progresses toward the apex.
Figure 2
COF running in a mesio-distal direction.
Figure 3
COF running in a facial-lingual direction
between cusps.