Contemporary Restoration of Endodontically Treated Teeth. Nadim Z. Baba
toward the crown. The incidence of VRFs in restored endodontically treated teeth ranges between 2% and 10%.32–37
Fig 2-9 (a) VRFs (arrow) occur mostly in endodontically treated teeth and typically originate from the apical end and progress toward the crown; they usually run in a faciolingual direction in contrast to infractions, which run mesiodistally. (b) The fracture (arrow) is evident in the extracted tooth.
VRFs are sometimes mistaken for failing RCTs. This is understandable because the complaints and clinical findings often are similar. The management for these two conditions is not the same, so the correct diagnosis is essential to determination of the best treatment.
A VRF can be differentiated from a failing RCT by a number of factors: the history of the tooth’s treatment, presenting signs and symptoms, radiographic information, and data from the clinical examination.31, 38–42
Typically, a VRF appears a considerable time after RCT and restoration of the tooth. The tooth may have been comfortable and fully functioning for years when suddenly it begins to feel uncomfortable during chewing; there may also be a sudden appearance of some swelling, usually on the facial aspect of the tooth.
Radiographically, if a lesion has developed, it appears to be located along the length of the root; in contrast, if the lesion is the result of a failing RCT, the lesion appears more apical to the root. Because fractures associated with VRFs tend to have a faciolingual orientation, it is not unusual for fracture lines to be visible radiographically. In maxillary premolars and the mesial roots of mandibular molars, a “halo” appearance involving the apical and lateral aspects may be noted on one side or both sides of the involved roots.41, 43
As with many other dental conditions, direct observation can often provide the definitive information for arriving at a diagnosis of VRF. For instance, it is often possible to probe a fairly narrow periodontal pocket along the fracture line to the root apex. In contrast to infractions, which originate in the crown of the tooth, VRFs originate in the apical part of the tooth and progress in a coronal direction. When a VRF is suspected, a minor surgical exploration accomplished by reflection of a small tissue flap in the area will often reveal the fracture line. Another distinct difference between an infraction and a VRF is that the former is very small (until the tooth splits), while the latter by comparison is quite wide in diameter.
Treatment for a tooth with a VRF is usually extraction, which should be performed as soon as possible after the diagnosis to preserve as much of the adjacent alveolar bone as possible. Because the symptoms are often minimal, patients may want to postpone treatment, but this delay results in a very poor alveolar ridge after extraction. This problem should be carefully explained to the patient.
There is one exception to the recommendation for extraction of teeth with VRF: When the involved tooth is a multirooted maxillary molar and the fracture is located in one of the facial roots (Fig 2-10), surgical resection of the affected root may leave a tooth that can still function quite well for many years, as has been demonstrated in the periodontal literature.44
Fig 2-10 (a) The mesiobuccal root of the maxillary left first molar has developed a vertical root fracture. (b) After the prosthetic crown has been removed, the mesiobuccal root is resected, leaving two roots to support the new restoration. (c) The 3-year follow-up radiograph shows a wellfunctioning tooth (which is still functioning at the time of writing).
Combined endodontic-periodontal problems
A difficult diagnostic and treatment-planning problem is the combined endodontic and periodontal situation. The tooth’s pulpal and periodontal tissues are closely connected both at the apical opening of the root canal and through the many lateral connections present. This in part explains the difficulty in deciding the origin of some periradicular lesions.
The unfortunate result is that in some cases, teeth receive RCT even though the pulps may be healthy, or they may be extracted when associated with lesions that are presumed to be of severe periodontal origin, and the teeth are not expected to survive. To prevent such mistakes, clinicians must carefully arrive at the correct diagnosis based on collection of pertinent information such as the status of the dental pulp, evaluation of periradicular lesions, and consideration of other conditions such as infractions or VRFs. After the collection of adequate data, one of the following diagnoses may be applied: pulpal disease, periodontal disease, or a true combination of the two.
Pulpal disease can cause periradicular lesions that radiographically appear similar to those of periodontal disease (Fig 2-11). Pulp testing to determine the status of the pulp can clarify the situation in most cases, although even necrotic pulps may have pain receptors that can be stimulated in pulps that are far from healthy. If the testing indicates pulpal disease, then RCT can result in healing of any periradicular lesion that may be present.
Fig 2-11 (a) Radiograph of the maxillary right second premolar of a patient who complained about soreness around the tooth. The tooth did not respond to cold stimuli. There was a 6-mm narrow periodontal pocket on the mesial aspect of the second premolar, and the tooth was sensitive to percussion. Based on the findings, a diagnosis of pulpal necrosis was made. (b) RCT has been completed, and the diagnosis of pulpal necrosis has been confirmed. (c) The 7-month follow-up radiograph shows the healing of the initial lesion. The tooth is comfortable, and no periodontal treatment has been necessary. (Courtesy of Dr Harold “Jay” Jacobson, El Cajon, CA.)
Periodontal disease involving a single tooth is not common, so when that occurs it is easy to suspect the presence of pulpal disease. Pulp testing, along with clinical examination, may provide enough information to decide if the condition is related to the pulp or PDL. In general, periodontal probing will reveal wider pockets when the lesion is of periodontal origin. Lesions of pulpal origin tend to be narrower, similar to those seen in teeth with infractions or VRFs. Occasionally it may be so difficult to obtain reliable information about the status of the pulp that an exploratory pulpectomy may be indicated to allow a definitive diagnosis. The bottom line, however, is that if a periradicular lesion is not of pulpal origin, RCT will not change the situation.
True combined lesions of endodontic and periodontal origins do occur. If a thorough examination reveals that such a diagnosis is appropriate, RCT is likely to have some positive effect on the condition, but periodontal treatment is also needed.
Other factors may contribute to development of periradicular lesions. For instance, failing RCTs and poorly completed coronal restorations provide pathways for bacterial contamination. Linked directly with the need for adequate endodontic therapy is a good coronal restoration; coronal leakage has been well established as a major cause of endodontic treatment failure.45–47
Root perforations may be another cause of lesions of combined endodontic-periodontal origin (Fig 2-12). These perforations may result from extensive caries lesions, resorption, or from operator error during canal instrumentation or post space preparation.48
Fig 2-12 (a) A root perforation was created during post space preparation of a mandibular left second molar; a further treatment error was cementation of a post into the perforation. (b) A follow-up radiograph taken 6 months after retreatment and repair of the perforation shows that the apical lesions have healed satisfactorily; however, a furcal lesion has developed as a result of the perforation.