After the pulp becomes necrotic, bacterial growth can be sustained within the canal. When this infection (or the bacterial toxins from this infection) extends into the periodontal ligament space, the tooth may become symptomatic to percussion or exhibit spontaneous pain. Radiographic changes may occur, ranging from a thickening of the periodontal ligament space to the appearance of a periapical radiolucent lesion. The tooth may become very hypersensitive to heat, even to the warmth of the oral cavity, and is often relieved by applications of cold. As previously discussed, this may be very helpful in attempting to localize a necrotic tooth when the pain is referred or nonlocalized.
A tooth with acute periradicular periodontitis will have a very painful response to biting pressure or percussion. This tooth may or may not respond to pulp vitality tests, and the radiograph or image of this tooth will generally exhibit a widened periodontal ligament space but no periradicular radiolucency.
A tooth with chronic periradicular periodontitis generally presents with no clinical symptoms. This tooth does not respond to pulp vitality tests, and the radiograph or image will exhibit a periradicular radiolucency, usually around the apical third of the root. This tooth is generally not sensitive to biting pressure but can "feel different" to the patient upon percussion.
Date Added: 26 April 2006
Karl Keiser, DDS, MS; University of Texas Health Science Center at San Antonio
Can teeth with periapical lesions of endodontic origin harbor vital pulp tissue?
The determination of working length during root canal instrumentation is a critical, yet potentially fallible, aspect of nonsurgical root canal therapy. The astute clinician uses several pieces of information to decide on the proper termination of root canal preparation and obturation, including radiographic interpretation of a file placed to estimate working length, the information gathered from electronic apex locators, the presence or absence of tissue fluids on a measured paper point, and tactile sense of the position of the cementodentinal junction (CDJ). Based upon these varied sources of information, a very well educated guess is made. The only way to know with certainty the position of the CDJ and apical foramina is to extract the tooth and examine it histologically, obviously not an option during endodontic therapy!
It is likely that the experienced clinician has treated cases with obvious periapical radiolucencies of pulpal origin and noted a painful response to instrumentation short of the determined working length in the apical portion of the root canal. It is tempting to call this "physiologic working length," assuming that the instrument has reached vital periapical tissues via an apical foramen. This is based upon the supposition that in a case with no response to vitality testing and a radiographically demonstrable lesion, the pulp is totally necrotic. There is a growing body of evidence, however, that suggests that this is not always the case.1,2,3 Recently, Ricucci et al. examined diseased apical tissues attached to 50 non-endodontically treated extracted human teeth.4 The teeth were decalcified after fixation, and the soft tissues attached to the root-ends were processed for routine serial microscopic examination along with the adjacent hard-tissue structures. Histological diagnosis indicated the presence of 20 granulomas, 14 abscesses, and 16 cysts, of both the "true cyst" and "bay cyst" variety.5 Interestingly, 36% of the specimens had vital pulp tissues in the apical root canal, despite the presence of periapical lesions of endodontic origin. The authors speculate that since the etiology of periapical pathosis is the presence of bacteria and/or their toxins (see Chapter 14 by Dr. Nair for an excellent review), it is possible that these components may diffuse out of the infected root canal and into periapical tissues via blood vessels and lymphatics in vital pulp tissues, eliciting a periapical response before total pulp necrosis occurs.
1. Lin L, Shovlin F, Skribner J, Langeland K: Pulp biopsies from the teeth associated with periapical radiolucency. J Endod 10:436-448, 1984. MedlineSimilar articles
3. Ricucci D, Langeland K. Apical limit of root canal instrumentation and obturation, part 2. A histological study. Int Endod J 31:394-409, 1998.
4. Ricucci D, Pascon EA, Ford TR, Langeland K: Epithelium and bacteria in periapical lesions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 101:239-249, 2006. MedlineSimilar articles
5. Nair PNR, Pajarola G, Schroeder HE: Types and incidence of human periapical lesions obtained with extracted teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 81:93-102, 1996. MedlineSimilar articles
A tooth with an acute periradicular abscess will be very painful to biting pressure, percussion, and palpation. This tooth will not respond to any pulp vitality tests and will exhibit varying degrees of mobility, and the radiograph or image can exhibit anything from a widened periodontal ligament space to a periradicular radiolucency. Swelling will be present in the mucobuccal fold and facial tissues adjacent to the tooth. The patient will frequently be febrile, and the cervical and submandibular lymph nodes will be tender to palpation.
A tooth with a chronic periradicular abscess (suppurative periradicular periodontitis) will not generally present with clinical symptoms. This tooth will not respond to pulp vitality tests and the radiograph or image will exhibit a periradicular radiolucency. The tooth is generally not sensitive to biting pressure but can "feel different" to the patient upon percussion. This entity is distinguished from chronic periradicular periodontitis because it will exhibit intermittent drainage through an associated sinus tract.
Endodontics is a multifaceted specialty, with much emphasis on how cases are clinically treated. Clinicians have increased their ability to more accurately perform endodontic procedures by way of an increased visualization using DOMs, precise apical foramen detection using electronic apex locators, enhanced imaging techniques using digital radiography, and more. Practices have incorporated more refined canal cleaning and shaping with ultrasonics and rotary-driven nickel titanium files facilitated with computer-assisted electronic handpieces. There have been many other recent advancements-all for the sake of achieving an optimal result during endodontic treatment. However, these advancements are useless if an incorrect diagnosis is made. Before the clinician ever considers performing any endodontic treatment, the following questions must be answered:
Is the existing problem of dental origin?
Are the pulpal tissues within the tooth pathologically involved?
Why is the pulpal pathosis present?
What is the appropriate form of treatment?
Testing, questioning, and reasoning are together combined in order to achieve an accurate diagnosis and to ultimately form an appropriate treatment plan. The art and science of making this diagnosis are the first steps that must be taken before initiating any treatment.
1. American Association of Endodontists: Glossary of Endodontic Terms, ed. 7, 2003.
2. American Association of Endodontists: Press release, May 8, 1998.
3. Anderson RW, Pantera EA: Influence of a barrier technique on electric pulp testing, J Endodon, 14:179, 1988.
4. Arakawa S, Cobb CM, Rapley JW, Killoy WJ, Spencer P: Treatment of root fracture by CO2 and Nd:YAG lasers: an in vitro study, J Endodon 22:662, 1996.
5. Augsburger RA, Peters DD: In vitro effects of ice, skin refrigerant, and CO2 snow on intrapulpal temperature, J Endodon 7:110, 1981.
6. Baumgartner JC, Picket AB, Muller, JT: Microscopic examination of oral sinus tracts and their associated periapical lesions, J Endodon 10(4):146, 1984.