Vertical root fractures can be detected early by listening to the patient’s chief complaints, carefully examining radiographs and performing a thorough clinical examination.

Trauma is the most likely cause of VRFs in vital teeth, typically occurring from physical trauma, clenching or bruxism,^8(pp1,30) or occurring in teeth undergoing apexification.⁹ Early diagnosis of a VRF usually begins with gathering a comprehensive dental history, listening well to the patient, asking many questions and encouraging the patient to recall when the symptoms first occurred.^8(pp1,30)

The purpose of this study was to show clinicians how to identify the most prominent clinical and radiographic findings that might indicate a VRF, and how to differentially diagnose the VRF from recurrent endodontic or periodontal disease.

	SUBJECTS, MATERIALS AND METHODS

TOP ABSTRACT SUBJECTS, MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
During a five-year period (1996 to 2001) we conducted an examination of 36 patients (25 women and 11 men) with 36 teeth having VRFs. The mean age of patients was 52 years, with a range from 40 to 65 years. We observed VRFs in 34 endodontically treated teeth that had been restored with dowel cores; two of these teeth had been restored with glass ionomer cement and resin-based composite. We observed VRFs in two vital teeth; the dental history of these patients revealed that they had destructive parafunctional habits (that is, clenching or bruxing). Absent control subjects and a larger number of patients, we did not design this investigation for statistical analysis.

We made the diagnosis of VRFs through the patient’s dental history and clinical and radiographic examination findings. A thorough clinical examination was performed, which included the following: age of patient; pulp vitality; type of restoration (with or without post and crown) using glass ionomer cement, resin-based composite or amalgam; degree of pain, if any; presence or absence of swelling; presence or absence of sinus tract; depth and extent of any periodontal defects; degree of mobility (within normal limits, mild, moderate or severe); and any history of post or restoration dislodgement or oral trauma.

The 34 vertical root fractures in the nonvital teeth resulted from excessive operative procedures performed in the root canal after endodontic therapy.

In addition, we noted radiographic findings, which included the following: thickening of the periodontal ligament, or PDL; peri-radicular "halo" radiolucency; loss of attachment apparatus seen as a deep, narrow, isolated periodontal pocket; and a separation (or not) of the root fragments.

We noticed that when swelling and a sinus tract were observed, a no. 25 gutta-percha cone placed into the sinus tract may have run parallel to the PDL, often only tracing to the middle of the root as opposed to the apex. In such cases, one might reasonably suspect a VRF, thus enabling the clinician to make a differential diagnosis between a VRF and periapical or periodontal pathology (Figure 2).

View larger version (109K): [in this window] [in a new window]   Figure 2. A no. 25 gutta-percha cone placed into the sinus tract of a 45-year-old woman. Note that the cone follows the periodontal ligament, which strongly suggests a vertical root fracture.

	RESULTS

TOP ABSTRACT SUBJECTS, MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
We observed VRFs in 36 teeth, two of which were vital; the other 34 were nonvital (endodontically treated). The 34 VRFs in the non-vital teeth resulted from excessive operative procedures performed in the root canal after endodontic therapy. Thirty-one (91 percent) of these 34 VRFs were due to poorly designed dowels (too long, too wide or both) or the inappropriate selection of the tooth as a bridge abutment; two VRFs (6 percent) were due to a restoration that exerted lateral pressure on the axial walls of the preparation; and one VRF (3 percent) was due to overzealous endodontic forces. The VRFs in the two vital teeth were in men who had a history of bruxism or clenching.

In this investigation, we found VRFs in the following locations:

– 12 maxillary premolars (33.3 percent) (nine of which were bridge abutments);

– 11 mandibular premolars (30.6 percent) (eight of which were bridge abutments);

– nine mesial roots of mandibular molars (25 percent);

– two maxillary lateral incisors (5.6 percent);

– two maxillary canines (5.6 percent).

In the 36 teeth we examined, it appeared that when premolars were used as bridge abutments, a surprising number of these abutments sustained a VRF. We believe this may be because these roots have a narrow mesiodistal dimension. When the dowel in a restored tooth (whether cast or preformed) becomes dislodged more than once (and the post and crown are well-designed), this strongly suggests the likelihood of a VRF (Figures 3 through 5).

View larger version (60K): [in this window] [in a new window]   Figure 3. A. Radiograph of a second mandibular premolar serving as a bridge abutment in a 49-year-old woman. Note the periradicular "halo" surrounding the root. B. Separated root fragments after extraction.

View larger version (90K): [in this window] [in a new window]   Figure 4. Radiograph from a 42-year-old woman with a vertical root fracture in a maxillary lateral incisor. Note the excessive canal shaping and large dowel. Radiograph shows the presence of a radiolucent halo on the distal aspect of the root, with bone loss (arrow).

View larger version (102K): [in this window] [in a new window]   Figure 5. A. Preoperative radiograph from a 52-year-old woman who had complained of pain and swelling. Note the dowel, periapical radiolucency and loss of attachment apparatus. B. After removal of the dowel, the vertical root fracture with separated root fragments was visible. C. Radiograph after the dowel was removed.

View larger version (113K): [in this window] [in a new window]   Figure 6. Radiograph from a 51-year-old woman who had complained of pain while chewing. Note the thickening of the periodontal ligament along the distal aspect of the root (arrow).

	DISCUSSION

TOP ABSTRACT SUBJECTS, MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Complete or incomplete VRFs constitute an ongoing problem in dentistry because they are difficult to diagnose in the early stages. In most cases, tooth extraction is the only reasonable treatment when the VRF is finally diagnosed. (Early detection in a multirooted tooth might allow timely removal of the broken root and possible retention of the remaining portion of the tooth.) Commonly, patients complain that ever since they bit down on something hard (such as a popcorn kernel, cherry pit or piece of bone), they felt a jolt of pain, and may state that "since then, the tooth just never felt right." In the early stage, patients may notice a mild discomfort when biting or chewing,^8(pp1,30) or pain with lateral percussion. In the more advanced stage, patients commonly have noticeable gingival swelling, moderate pain (with or without a sinus tract) or both. In these cases, the prognosis is unfavorable and tooth extraction clearly is indicated.^{1–8(pp1,30)9,10}

Etiology. Factors in the development of VRFs may include one or more of the following:

Excessive canal shaping. Excessive canal shaping during endodontic treatment, especially in teeth with curved roots that are narrow in the mesiodistal plane (that is, the danger zone) can lead to development of a VRF.¹¹ This is why maxillary second premolars, mesiobuccal roots of maxillary molars, mesial roots of mandibular molars and mandibular premolars are most prone to VRFs. In our patients, we found that VRFs were present less frequently in maxillary lateral incisors and maxillary canines^{1–8(pp1,30)9,10} (Figures 3 through 5). In addition, excessive removal of tooth structure contributes to the overall weakening of the tooth, which promotes a higher incidence of VRFs.

A comprehensive, detailed dental history typically yields the initial clues suggesting a vertical root fracture.

Excessive hand pressure. Excessive hand pressure during lateral or vertical compaction of gutta-percha can result in development of a VRF.^3,4

Excessive restorative procedures. When preparing a canal to place a dowel, the clinician must ensure that the width and length of the dowel space are appropriate for the anatomy of the canal to avoid weakening the walls by making them too thin. Furthermore, a dowel must be cemented passively (that is, avoiding pressure that may wedge the dowel into the canal, thus splitting the root), because the cement produces hydrostatic pressure in the root canal that may lead to the development of a VRF.⁷ In addition, tapping a dowel or cast intracoronal restoration into place may contribute to the development of VRFs.

Inappropriate choice of tooth for a bridge abutment. Choosing an inappropriate tooth for a bridge abutment may contribute to the development of a VRF (for example, mandibular incisors with a 1:1 crown/root ratio or the inappropriate use of a tooth to support a cantilever).^5,6,12,13

Several studies^4–6 have been conducted regarding whether post-retained restorations have the potential effect of weakening the root and predisposing the tooth to VRFs.⁶

Some VRFs may begin with an incomplete VRF. Cameron¹⁴ described this initial crack (known as cracked tooth syndrome) as a break or split in the continuity of the root surface without a perceptible separation.

Diagnosis. The patient initially may complain of a sharp pain during chewing or biting of hard food, as well as occasional pain on consumption of cold food or drinks, because the dentin (and sometimes the pulp) is affected by the VRF.^8(pp1,30) This is seen more frequently in teeth with large restorations, especially molars,^15,16 which involve the dentin (and sometimes the pulp), thus differing from small enamel fracture lines.^8(pp1,30) By removing the restoration, the clinician can perform a direct visual examination while searching for a crack.^15–17 The ridges of the mesial and distal margins should be evaluated carefully, since these areas are most predisposed to crack.

A comprehensive, detailed dental history typically yields the initial clues suggesting a VRF.⁹ Furthermore, strong coaxial illumination along with good magnification are essential to identify a VRF. With this foundation, clinicians can conduct the following tests.^{8(pp1,30)15–17}

Bite test. To reproduce the biting and chewing pain described by the patient, the dentist may use rubber wheels, cottonwood sticks or some other elements (such as Tooth Slooth fracture detector, Professional Results, Laguna Niguel, Calif.) to replicate masticatory motion. This test can be performed tooth-by-tooth or cusp-by-cusp. When the patient responds with pain, the dentist should inquire if the pain is similar to his or her chief complaint.

Transillumination test. Shining a strong fiber-optic light through the tooth (providing there is no restoration to block light transmission) in a horizontal direction at the gingival sulcus may help the clinician visualize a crack. If he or she finds a crack in the tooth, the light will be deflected at the crack, reducing its transmission through the tooth, and the fractured segment on the other side of the crack will appear darker (Figure 7).

View larger version (37K): [in this window] [in a new window]   Figure 7. The presence of a vertical root fracture sometimes can be observed using transillumination. As this figure illustrates, the part of the tooth closest to the light source will transmit light, but the root fracture will inhibit most of the light from reaching the part of the tooth beyond the root fracture.

View larger version (47K): [in this window] [in a new window]   Figure 8. As this figure illustrates, when probing a vertical root fracture, or VRF, the dentist typically finds a deep, narrow, isolated periodontal pocket over the bony dehiscence that was created secondary to the VRF.

View larger version (57K): [in this window] [in a new window]   Figure 9. A. Radiograph of a nonvital mandibular pre-molar with a cast inlay. B. A narrow, isolated, deep periodontal pocket found on probing. C. On extraction, a fracture was observed (arrows).

Pulp testing. Vitality tests (that is, electrical, thermal or laser Doppler flowmetry^8(pp1,30)) can be helpful in diagnosing a VRF, especially in ostensibly sound teeth. When the patient complains of a sharp, sudden pain, especially while chewing, pulp testing provides valuable diagnostic information.^8(pp431–6) Often, the fracture is incomplete but extends to the pulp, where it eventually causes necrosis. A nonvital tooth that is intact or has a minimal restoration is highly suggestive of a VRF (Figure 10).

View larger version (82K): [in this window] [in a new window]   Figure 10. A. Radiograph of a nonvital mandibular second molar with a minimal restoration. B. After the tooth was sectioned, a fracture was seen extending into the pulp (arrows).

Radiographic examination. Although essential, radiographic images do not always reveal a VRF. Unless the X-ray beam is parallel to the fracture line (± 4 degrees), the root fracture will not be revealed.¹⁸

Surgical exploration. Surgical exploration may be advisable if a VRF is strongly suspected, but cannot be confirmed by other available techniques. (This consists of lifting a full-thickness flap and examining the bone and root directly with high-magnification and illumination.) There is no substitute for direct visualization if the diagnostic and prognostic assessment remains questionable.

Prognostic assessment. From our experience, the progression of a vertical crown fracture that is in an early stage (that is, it has not reached the pulp chamber or the furcation of a multirooted tooth) may be slowed or arrested by drilling out all evidence of the fracture line and restoring the tooth with a bonded restoration.^19,20 However, the clinician should advise the patient that the prognosis will remain guarded.

When a coronal crack crosses both marginal ridges and produces a split tooth,¹⁵ and when that split extends apically into the root, the prognosis is poor and extraction often is required. Immature, pulpless teeth that previously have undergone apexification treatment may have thin walls that might result in a greater potential for development of a VRF.⁹

Even with its intrinsic limitations, the radiographic examination is one of the most important methods for accurately diagnosing a VRF.^8(pp1,30)

When the VRF is at an early stage, it often is possible for the radiographic examination to reveal a thickening of PDL along one side of the root (Figure 6). As the VRF advances, a radiolucent halo of bone loss is observed along one side of the root. As the VRF advances further, the radiolucent halo may surround the entire root. This halo indicates that the root fragments have separated completely, along with the attached PDL; often, there is an associated deep pocket and loss of additional supporting bone^{8(pp1,30),21,22} (Figures 3, 8 and 9).

In our patients, we noticed that when swelling and a sinus tract were observed, a no. 25 gutta-percha cone placed into the sinus tract may follow (that is, run parallel to) the PDL. When observed, one may reasonably suspect a VRF, thus providing a technique to differentiate between a VRF and periapical or periodontal pathology (Figure 2). VRFs sometimes may be misinterpreted as being recurrent endodontic or periodontal disease if the clinician is not alert to the possibility of a VRF.

The clinician should be aware that when a deep, narrow, isolated periodontal pocket is associated with the affected tooth, a VRF is the most likely cause. However, when periodontal disease is present, there are several deep and wide periodontal pockets usually affecting several teeth (Figure 8).

Clinicians should suspect a VRF when a dowel dislodges more than one time. Some authors have suggested that the tooth with a VRF should be extracted; the root fragments should then be repaired via bonding with an adhesive resin cement; and the tooth should then be replanted.^23,24 However, we could find no long-term follow-up studies in the literature to substantiate this approach. Therefore, in the presence of a VRF, extraction is still the treatment of choice.

If a VRF develops in a multirooted tooth with a healthy attachment apparatus, the dentist might consider root resection, thus allowing a portion of the tooth to be preserved.^11–14 In the single-rooted tooth, however, extraction is the only treatment option at this time.

For patients who brux or clench, nightguards afford some protection to minimize the risk of VRFs.

	CONCLUSION

TOP ABSTRACT SUBJECTS, MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
VRFs present a challenge to the clinician in that the diagnosis often is difficult, and is based on some subjective parameters. It is important to recognize the sometimes subtle findings to properly inform patients, so that they have a better understanding of their prognosis and the potential for successful treatment.