200402Endo_Davich.qxd 12/3/04 1:52 PM Page 4

4 ENDODONTIC THERAPY VOL. 4 NO. 2 Clinical Detection and Decision-Making Considerations for Cracked Teeth Mitchell H. Davich, DMD, FACD, FICD*

FIGURE. Illustration demonstrates the theory that endodontic reality is largely based on findings described in clinical research and studies, as opposedto to empiricism come and theory.

ince was Undiagnosed or inclines, create a “hammer and anvil” Sdescribed 40 years ago,1 numerous misdiagnosed frac- chewing effect that can generate or propa- advancements in endodontic treatment and tures create delays, gate a crack. technology have occurred. Yet practitioners allowing the proliferation Patients with enlarged, overdeveloped still remain perplexed regarding the detection of fractures, and may thereby masticatory muscles usually present a of cracked teeth, perhaps because patients’ lead to more extensive treatment and an unfa- “square jaw” appearance. One can sometimes symptoms are often vague and radiographs vorable outcome. Since the ultimate goal for observe the tensing of their hypertrophic are usually normal. This resulting delay in the patient and dental practitioner alike is the masseter and temporalis muscles, as if these diagnosis and treatment can allow further preservation of the natural tooth, early and patients are chewing gum while sitting in the longitudinal progression of the fracture, both rapid treatment of cracked teeth is essential. dental chair. in time and spatial dimension,2 leading to Ten common characteristics are associ- Diets abundant in abrasive foods, such as eventual extraction. In industrialized nations, ated with cracked teeth (table). These signs rice, grains, and raw vegetables, predispose fractured teeth have been reported to be the may occur by themselves or in combination teeth to premature occlusal wear, thus weak- third-most common cause of tooth loss.3 with others on the list. ening their cuspal integrity. Brow found that Given that presenting symptoms may be In Hiatt’s study, 74% of cracked teeth had teeth subjected to thermal cycling between 90 described only as a momentary unlocalized no proximal restorations, and 71% of frac- and 140 degrees had severe cracking.10 Con- sensitivity to chewing or a brief thermal sen- tures were found in mandibular molars.9 sequently, a habit such as ice chewing gener- sitivity, practitioners need to consider certain Sylvestri theorized that continued masticatory ates optimal conditions for the creation and predisposing conditions that may help direct forces on MOD preparations created internal proliferation of tooth fractures. them toward the proper diagnosis of a shearing forces, thus predisposing teeth to Patients presenting for cracked tooth cracked tooth. Correct diagnosis of a frac- off-center oblique cuspal fractures.5 evaluation often report a previous history of a tured tooth in its earliest possible stage Plunger cusps can be associated with fractured tooth. In several instances, the pre- encourages more conservative treatment various malocclusions and premature tooth viously cracked tooth is the contralateral options as well as an improved prognosis. loss. These, together with steep cuspal tooth to the one currently being examined for 200402Endo_Davich.qxd 12/3/04 1:53 PM Page 5

VOL. 4 NO. 2 ENDODONTIC THERAPY 5

fracture. Posterior teeth without full-coverage unrestored tooth with an lesion. making it difficult to determine the presence or restorations that have undergone endodontic Controversy still exists regarding whether or location of a tooth fracture. In addition, radio- therapy require cuspal fracture protection with not to restore abfraction lesions, but an graphic detection of cracked teeth is a permanent restoration, usually within one examination of the occlusal pattern and mit- difficult since most fractures are incomplete month of endodontic completion. Delaying igation of forces involved is of paramount and are surrounded by normal tooth structure permanent restorations or merely filling access importance in preventing fractures of teeth somewhere either buccally or lingually. Unless openings with amalgam or composite unneces- with abfractions. the central ray is exactly parallel sarily exposes endodontically treated teeth to Due to improvements in adhesive den- to the crack, it will not be visible on a periapi- the risk of fracture. tistry, intracoronal pin buildups for core cal or bitewing radiograph. Somtimes, Abfraction lesions,7 also called noncari- retention are not as common as in the past. software enhancement tools within digital ous cervical lesions (NCCL), are wedge- These buildups produce internal dentinal radiography systems aid in the evaluation of shaped circular invaginations that were once cracks during pin insertion, which can propa- radiographic images (Figures 5 through 8). thought to be related to abrasion gate laterally and apically, depending upon Direct visualization remains the most reliable (Figures 1 through 4). They are now known the demands placed on the restoration.8 For method for fracture diagnosis. Below is a list to be associated with occlusal wear facets this reason, the use of pins to reinforce of some clinical aids available for improving 94.5% of the time and with a lack of canine- buildups is now discouraged. visualization of fractures. guided occlusion 77.2% of the time.6 Exces- 1. Indirect illumination. This can be sive occlusal loading and flexure due to wear DETECTION accomplished with a battery-powered inspec- of the dentition have been suggested as pos- Patients with fractured teeth usually report tion light, a fiber-optic light, or an eye-pro- sible causes for fracture of a sometimes episodic vague and unlocalized symptoms, tected curing light by placing the illumination

Figure 1. Case 1. Dark, stained fracture line extends through buccal groove Figure 3. Radiograph after completion of endodontic therapy. Nondisplaceable and connects to abfraction lesion on buccal of tooth #30(46). Additional vertical fractures were found buccolingually and mesiodistally. fracture line can be seen on the mesial marginal ridge.

Figure 2. Radiograph denotes deep restoration of longstanding duration. Figure 4. One-year recall radiograph shows normal periapex. Tooth was Referring dentist saw no pathology and thought it best to observe since the restored with bonded core and full-coverage crown and is asymptomatic. amalgam restoration was intact. 200402Endo_Davich.qxd 12/3/04 1:53 PM Page 6

6 ENDODONTIC THERAPY VOL. 4 NO. 2

source against the buccal or lingual surface of They include: methylene blue, iodine, and 13). The decision to excavate should always the tooth. If the beam of light passes through caries detection dye. be made with the consent of the patient, since uninterrupted, this is usually a sign of a shal- 4. Chewing test. A cotton roll selectively it is not guaranteed that a fracture will be low enamel craze line. If, however, the light moved from tooth to tooth while the patient found underneath any removed restoration. beam does not pass totally through to the is chewing can help to pinpoint the general other side, leaving one side light and the location of a crack. It may not, however, EXTRACTION VERSUS RETENTION other dark, this is often an indication that an always be possible to identify in which arch Symptomatic fractures have been shown internal fracture exists.11 the offending tooth exists. to extend through the dentin and to be 2. Microscopic examination. The use 5. Hard bite test. A “Tooth Slooth,” extensively contaminated by bacteria.12 It is of the surgical operating microscope with “Fracture-Finder,” or wooden bite stick are unlikely that this bacterial contamination can its improved magnification to 16 and indispensable diagnostic tools for fracture be fully eradicated by sealants and restorative illumination has made it possible for much detection. By placing the concave end against materials. Even if symptoms temporarily better visualization of structural defects in individual cusp tips, pain is often experienced abate after excavation and temporization, teeth and restorations than with magnifying when releasing the bite, presumably because these teeth will eventually require endodontic loupes or the naked eye. Valuable informa- fluid within the fracture moves pulpally. This therapy and should be considered for imme- tion can be gathered from microscopic exam- particular reaction appears to be a unique fea- diate treatment to minimize subsequent pul- ination, which may help point the way ture of fractured teeth. pal and periapical breakdown and to toward correct fracture diagnosis. 6. Exploratory excavation. Sometimes maximize chances of tooth retention. 3. Staining. Various dyes can be used to exploratory excavation becomes necessary to Once a fracture has been visualized, a stain for direct visualization of fractures. obtain a visual diagnosis (Figures 9 through determination of its longitudinal depth and

Figure 5. Case 2. The patient’s right temporalis and right external pterygoid Figure 7. Postoperative radiograph shows bone loss into furcation and length muscles were tender to palpation. Fracture testing indicated sensitivity on of distal root. A nondisplaceable mesiodistal fracture was found. Surplus the distolingual surface of tooth #31(47). Pulp tests were normal for tooth sealer was extruded beyond apex of distal root during obturation. #30 and #31, but patient declined treatment initially.

Figure 6. Three months later, patient was unable to function on tooth #31 which Figure 8. Six-month recall radiograph shows complete healing. The tooth was was sensitive to heat and cold. Radiographically, an endo-perio lesion with exten- immediately provisionalized with an acrylic crown after endodontic therapy sive bone loss was noted to encompass the distal root from apex to gingival crest. and is now asymptomatic. 200402Endo_Davich.qxd 12/3/04 1:53 PM Page 7

VOL. 4 NO. 2 ENDODONTIC THERAPY 7

separability should be made. Fractures that necessary to determine whether this material extend below the furcation floor or into the can better protect an endodontically treated periodontium usually have a diminished cracked tooth from further injury and ulti- prognosis and should be considered for mately enhance the prognosis of these teeth. extraction, but can sometimes be treated with the patient’s informed consent, always CONCLUSION keeping in mind the goal of preserving the Fractured teeth present both a diagnostic and natural tooth. treatment dilemma. Practitioners should

If a horizontal or oblique cuspal fracture familiarize themselves with certain predis- Figure 9. Case 3. A symptomatic fracture was found is present, it must be removed and the tooth posing factors that may aid in fracture on tooth #14(26), which was prepared for a crown. When the symptoms did not resolve, the patient was assessed for restorability. Additional perio- detection and diagnosis. Early and rapid referred for endodontic evaluation and treatment. dontal crown lengthening may be required. treatment of cracked teeth is essential for a Most of these teeth are treatable, however, favorable outcome. Delayed or partial treat- and should be retained. ment worsens the prognosis by allowing frac- Regarding a mesiodistal or buccolingual tures to proliferate. Treatment protocol for fracture, excavation should take place to the cracked teeth depends upon the direct visual- depth of a Class II preparation; removal of ization of the fracture. The decision to extract the entire fracture may not be feasible in this or retain such teeth varies according to the situation. The displaceability can be checked location, displaceability, degree of perio- with a spoon excavator or similar instrument. dontal involvement, as well as the patient’s Figure 10. Occlusal view of tooth prior to excavation. Superficial dark-stained vertical fracture line is If the fractured segments can be separated, desire to retain the natural tooth for as long seen mid-palatally along outside surface of crown. then the prognosis is poor and extraction as possible. should be considered. If the fractured seg- ments are not displaceable, a bonded core and REFERENCES: provisional crown should be placed as soon 1. Cameron CE. Cracked-tooth syndrome. J Am Dent Assoc as possible after endodontic therapy. 1964;68:405-411. 2. Rivera EM, Williamson A. Diagnosis and treatment plan- It is feasible that additional fracture ning: Cracked tooth. Tex Dent J 2003;120(3):278-283. resistance may be obtained by using currently 3. Geurtsen W, Schwarze T, Gunay H. Diagnosis, therapy, available endodontic sealers containing glass and prevention of the cracked tooth syndrome. Quint Int 13 2003;34(6):409-417. and resin ionomers. Recently, a soft resin Figure 11. Fracture is excavated with round bur and 4. Ratcliff S, Becker IM, Quinn L. Type and incidence of extends into middle of crown both buccolingually endodontic obturation system was intro- cracks in posterior teeth. J Prosthet Dent 2001;86(2): and corono-apically. duced. Long-term clinical studies will be 168-172. 5. Silvestri AR. The undiagnosed split-root syndrome. J Am Dent Assoc 1976;92(5):930-935. 6. Miller N, Penaud K, Ambrosini P, et al. Analysis of etio- 10 Red Flags Associated logic factors and periodontal conditions involved with with Cracked Teeth 309 abfractions. J Clin Periodontol 2003;30(9):828-832. 7. Owens BM, Gallien GS. Noncarious dental “abfraction” lesions in an aging population. Compend Cont Educ Dent 1) Class I restoration with excursive 1995;16(6):552, 554, 557-558. 4 interference. 8. Standlee JP, Collard EW, Caputo AA. Dentinal defects caused by some twist drills and retentive pins. J Prosthet Figure 12. Fracture extends into pulp chamber but 2) Class II restoration with inadequate Dent 1970;24(2):185-192. is nondisplaceable and does not involve furcal 5 cuspal protection. 9. Hiatt WH. Incomplete crown-root fracture in pulpal- floor. Prognosis for successful endodontic therapy is favorable. This view also shows the orifices, for 3) Plunger cusp and/or malocclusion. . J Periodontol 1973;44(6):369-379. four canals prior to obturation. 10. Brown WS, Jacobs HR, Thompson RE. Thermal fatigue 4) Steep cuspal inclines. in teeth. J Dent Res 1972;51(2):461-467. 5) Hypertrophic masticatory muscles. 11. Liewehr FR. An inexpensive device for transillumination. J Endod 2001;27(2):130-131. 6) Abrasive diet and/or parafunctional 12. Kahler B, Moule A, Stenzel D. Bacterial contamination of habit. cracks in symptomatic vital teeth. Aust Endod J 2000; 26(3):115-118. 7) Previous history of cracked tooth. 13. Trope M, Tronstad L. Resistance to fracture of endodon- tically treated restored with glass ionomer 8) Unrestored root-canal–treated tooth. cement or acid etch composite resin. J Endod 1991; 17(6):257-259. 9) Abfraction lesion (NCCL).6,7 Figure 13. Postoperative image following obtura- tion. Tooth was eventually restored with a bonded 8 10) Intracoronal pins. *Private practice, Morristown, NJ. He may be core buildup and full-coverage restoration. contacted at [email protected].