Keywords
VRF - cracked tooth - probing depth - bruxism - RCT - periodontal abscess
Introduction
According to the American Association of Endodontists (AAE), five categories of cracks
are craze lines, fractured cusp, cracked tooth, split tooth, and vertical root fracture
(VRF).[1] Sharp pain during mastication, sensitivity to cold and ache or pain on the release
of bite force, is characteristic of cracked tooth syndrome.[2] Advanced cracks in teeth are associated with deep probing depths of >6 mm, which
is an important element in the prognosis of the tooth. Intact teeth are associated
with 65% prevalence of cracks.[3] As per the Glossary of Endodontic Terms, AAEs, a VRF is an incomplete root fracture
that may occur buccolingually or mesiodistally; it may cause periodontal defect(s)
or sinus tracts and may be radiographically evident. It can be either complete or
incomplete and confined to the root.[4]
[5]
A VRF is a complex clinical scenario that mostly occurs due to the production of lateral
wedging forces during compaction of gutta-percha for obturation or post-placement,
which can induce stresses and strains during root canal treatment (RCT).[6]
[7]
[8]
Additional masticatory forces in patients with chronic parafunctional habits can lead
to the extraction of the affected tooth. It is also be detected in intact teeth in
patients with chronic trauma from occlusion such as bruxism, clenching, eating hard
foods such as nuts, and thermal cycling.[3]
[9]
The teeth most predisposed to fracture are the premolars of the maxilla and mandible,
the mandibular incisors, mesial root, mesiobuccal roots of the mandibular molars,
and maxillary molars.[10]
This type of fracture is usually diagnosed by secondary symptoms that develop following
the primary treatment, often when the coronal restoration has already been completed.
The fracture line itself is often not directly visible, and therefore, the history,
clinical, and radiographic signs and symptoms are important factors that can lead
to a correct diagnosis. It is vital to pay attention to the patient's chief complaints,
a thorough clinical examination and proper scrutiny of periapical and bitewing radiographs.[11] Hence, in more advanced cases, it requires an interdisciplinary approach with an
endodontist and periodontist to rule out similar appearing endodontic–periodontal
lesions.
Etiology
Because of the devastating effects and the lack of treatment modalities for VRF, it
is very critical to identify the etiology. Many such etiologies have been suggested,
they can be categorized as predisposing and iatrogenic factors ([Table 1]).
Table 1
Predisposing and Iatrogenic factors of VRF
|
Predisposing factors
|
Latrogenic factors
|
|
Excessive occlusal loads or intensity of such loads
|
Root canal treatment procedures
|
|
Trauma, bruxism, and clenching
|
Intraradicular dowels
|
|
Previous cracks in dentin
Caries
|
Wedging forces of post placement and obturation
|
|
Anatomy of the roots—mesiodistal and bucco-lingual dimension
|
|
|
Oversized post preparation leading to a weakened tooth structure, excessive pressure
during cementation of posts
|
|
|
Obturation-related stress and strain in the roots
|
|
|
Post or pin corrosion
|
|
Clinical Manifestation
Early Manifestation
The probability of a VRF should be borne in mind if a well-completed root canal-treated
tooth does not resolve after completion. When “pain on biting” complemented with a
“bad taste” is present in a root canal-treated tooth, a VRF can be suspected.[12]
Commonly, patients complain they felt a jolt of pain on biting hard food like nuts
and may state that “since then, the tooth felt different.” In the initial stages,
the patient may notice a mild discomfort when biting or chewing, sensitivity, or pain
on lateral percussion. In a study evaluating root canal treated, vertically fractured
teeth, Tamse et al detected that 50% or more patients reported some kind of dull ache
and pressure on biting. Chronic inflammatory lesion in the area was reported in 35%
of patients in the form of an abscess.[13]
If the fracture and subsequent infection are allowed to progress, a deep narrow probing
will be evident along the fracture location, swelling often occurs in the attached
gingiva, and a sinus tract may be located more coronally, compared with an apical
location of a sinus tract in the case of chronic periapical abscess ([Figs. 1] and [2]). The point of sinus tract drainage is called a stoma or parulis. This mostly indicates
the presence of necrotic pulp and chronic periapical abscess. These signs and symptoms
have to be differentiated from nonhealing RCT that are very similar.[2]
Fig. 1 Depicting abscess located on the attached gingiva and sinus tracing with gutta-percha.
Fig. 2 Depicting deep narrow periodontal probing on a tooth with a sinus tract coronally
located on the attached gingiva.
Late Manifestation
As the fracture progresses, the periodontal probing pattern that was narrow and deep
later becomes wider and deeper at the fracture location. In well-established chronic
cases, the bone destruction is extensive, the root fragments may separate, and radiographically
an objective root fracture is detected. In such cases, the prognosis is poor and tooth
is indicated for extraction.[2]
Of 35% of patients with a sinus tract, 24% presented with deep osseous defects buccally,
and in 13–42% patients, a sinus tract was observed by Tamse et al on the evaluation
of VRFs in endodontically treated teeth. The sinus tract location was typically closer
to the marginal gingiva, as in contrast to failed RCTs in which sinus tracts often
are in an apical location. Many patients examined had buccal and lingual/palatal sinus
tracts, at both aspects. This is a characteristic and typical sign for a VRF.[13]
Implications: Avenue for bacterial ingress leading to
-
Pulpal pathosis
-
Periodontal pathosis
-
Failed RCT
Periodontal Manifestations
Periodontal Manifestations
Complete or incomplete VRFs extend to the supporting periodontium. The resultant soft
tissue ingrowth into the fracture space intensifies the separation of the root segments.
Bacteria, debris, and foreign material make a pathway through the gingival sulcus
into the fracture zone while communicating with the oral cavity. This invasion results
in an inflammatory process, resulting in the destruction of the supporting periodontium
and granulation tissue formation, thereby a rapid progression of the bony defect in
an apical and interproximal direction. Periodontal breakdown and bone resorption are
quicker in premolars, i.e., in premolars of the maxilla where the buccal cortical
plate is thin and the mesial roots of the mandibular molars, the most prone to fracture.
Most commonly dehiscence-type bone resorption in the buccal cortical plate develops
in teeth associated with a periodontal abscess.[6] When the fracture does not involve the coronal or apical aspect of the root, fenestration-type
bone defects can be observed on the buccal aspect.[14]
Probing Pattern
A deep narrow isolated probing pattern adjacent to the fracture site is a common feature
of VRF teeth. Bilateral probing patterns may be visible in a through and through fracture.
The probing pattern should be differentiated in VRF that is narrow/wide but localized
compared with a generalized wider consistent conical probing pattern in periodontitis.[15] A sudden deep dip of the periodontal probe in an isolated location around the circumference
of the tooth in the presence of otherwise normal attachment usually indicates a fractured
root ([Fig. 2]). A characteristic indication of a fracture would be two deep probing depths on
opposite sides of the infection. Teeth with large restorations may necessitate complete
removal of the restoration before deep interproximal periodontal probing of molar
teeth with fractures mesiodistally.[12]
Bone Resorption Pattern
Periodontal breakdown and bone resorption are rapid in premolars where the buccal
cortical plate is thin.[4] An initial dehiscence-type defect forms in the buccal plate that resorbs apicocoronally.
As the fracture advances, the bone defect becomes wide with extension inter-proximally
and laterally. This is best observed by the reflection of a full-thickness periodontal
flap and thorough debridement.
Diagnosis
The diagnosis of VRFs should carefully take into consideration the patient's chief
complaint, a thorough dental history, and detailed clinical examination. After which,
based on the location of the fracture and periodontal involvement, the prognosis assessment
and steps in the management must be considered. Since there is no single specific
indicator of VRF, a combination of all aspects, clinical, and radiographic analysis
is mandatory in the diagnosis.
Clinical Examination
-
Patient history—Patients may convey a long history of undiagnosed pain or sensitivity on related
or adjacent to a given tooth, despite several clinical and radiographical examinations.
Sensitivity and discomfort while chewing are also common complaints.
-
Hard tissue examination—A bite test using a Tooth Slooth (Professional Results, Laguna Niguel, CA, United
States) or a similar device can be used to detect a cracked tooth.[2] When the patient bites down on the Tooth Slooth, it will reproduce the sensation
of a sharp pain of the chief complaint or pressure upon release.[16]
-
Soft tissue and gingival examination—Visual examination of gingival swelling and sinus tract formation is a crucial step.
Fistula tracking is done by inserting a semi-rigid radiopaque material into the sinus
track until resistance is met. Taking a second radiograph with the insertion of a
material such as gutta-percha cones into the sinus tract will indicate the course
of the sinus tract and the origin of the lesion ([Fig. 1]).[15]
[17]
-
Periodontal probing—A periodontal probe is a mandatory requirement in the armamentarium. The probing
depth must be carefully evaluated around the involved and adjacent teeth.
-
Staining—Methylene blue or tincture of iodine dyes can help detect a fracture line. A cotton
pellet soaked with methylene blue dye is swabbed on the dried occlusal surface of
the tooth. The patient is asked to bite down an object like a stick, along with lateral
jaw movements. This enables the dye penetration into the fracture area. Subsequently,
the dye is rinsed from the tooth surfaces and a distinct fracture line is visualized
with magnifying loops or microscopic examination.[17]
-
Pulp testing—Pulp testing is carried out to determine the pulpal innervation of the affected tooth.
-
Magnification and transillumination—Magnification of the area with loupes or an operating microscope can be of value
when looking for a crack. Large intracoronal restorations need to be removed prior
to transillumination. If the tooth does not have an extensive intracoronal restoration,
fiber optic transillumination in a dark room will penetrate the tooth structure, leaving
the area beyond the crack dark, thus disclosing the crack.[2]
-
Radiographs—The root canal-treated tooth may appear normal radiographically. Often, periapical
radiographs at different angulations may be necessary to verify the existence of a
fracture. The commonly occurring radiographic features of VRFs are the “halo” appearance.
There may be a radiolucency in one or both sides of the root, radiolucency along the
root laterally, or angular radiolucency from the bone crest ending by the root side.
Space besides a post or root filling may also be detected.[18]
[19]
[20]
-
Exploratory surgical assessment—Surgical full-thickness flap reflection may eventually be required to visibly confirm
the presence of a root fracture along with the type of bone loss. This will provide
a confirmatory diagnosis of VRF to the clinician.[14]
-
Cone-beam computed tomography (CBCT)—Although CBCT has been used and there are some cases where it was helpful, the main
problem with it is the masking of the fracture line by the obturating material or
posts making it an unreliable tool. With the current CBCT devices, unseparated fracture
width may be too small and undetectable. The smallest voxel size of approximately
0.075 mm is currently available for a CBCT device. Hence, CBCT imaging would not be
able to visualize a root fracture of greater than 0.15 mm width.[2] The literature from meta-analysis and systematic reviews conclude that the use of
CBCT in the detection of VRF as a diagnostic tool may be unreliable.[21]
[22]
[23]
Prognosis and Management
The severity, position of the crack, and discomfort experienced by the patient determine
the prognosis and management. When the crack is minute without pulpal involvement,
resins, inlays, or crowns may be used to restore the tooth in a conservative manner.[24] RCT is mandatory in patients with worsening chronic symptoms such as tooth hypersensitivity,
pulpal involvement periodontal abscess, and deep probing depths, prior to completing
the coronal restoration. Early detection of cracked and fractured teeth can enable
the establishment of conservative preventive strategies to avoid complications.
Single-rooted teeth generally have a poor prognosis when there is advanced involvement.
Molars, on the contrary, can be salvaged by treatment with root resection and hemisection
and coronal restoration. Persistence of symptoms, severe destruction of the underlying
periodontium, and loss of attachment can hamper the prognosis and lead to the extraction
of the tooth.[3]
[14]
[25] In patients with suspected VRF with severe periodontal destruction, tooth or root
extraction is recommended at the earliest. Any delay may possibly compromise the replacement
with an endosseous implant. Thus, all precautionary and diagnostic measures are necessary
at an early stage. Several efforts at repairing fractures with a variety of restorative
materials like cyanoacrylates have been reported in the literature; yet, none of the
outcomes of these treatment options is regarded as a dependable long-term solution.[2]
[5]
Conclusion
VRFs are challenging and confusing to detect clinically. Various tests along with
the patient's signs, symptoms, and history must be meticulously considered to arrive
at a confirmatory diagnosis. It is important to detect the causative factor/s to determine
the prognosis of such teeth and the best treatment option. Hence, early detection
is vital and can be managed conservatively since the management depends on the extent
and severity of the lesion.
Heroic attempts to treat such teeth with conservative approaches in most cases may
not be possible. Following root canal treatment, a coronal restoration is mandatory.
Single-rooted teeth generally have a poor prognosis, whereas it may be possible to
save multirooted teeth. Progress into the underlying periodontium with severe bone
loss can hamper the prognosis of such teeth and lead to extraction.
