Crown Fractures
Treatment of Crown Fractures With Exposed Pulps
Lucía Blanco, DDS, and Stephen Cohen, MA, DDS
Copyright 2002 Journal of the California Dental Association.
About the Authors:
Lucía Blanco, DDS, is a member of the International Council in Dental Trauma and maintains a private endodontic practice in Argentina. He is a consultant on dental trauma for several hospitals in Argentina and a professor in the postgraduate school of the Argentine Association of Dentistry. He is currently president of the Dental Trauma Committee of the Argentine Society of Medicine and Trauma Surgery.
Stephen Cohen, MA, DDS, is the senior editor of all eight editions of the endodontic text Pathways of the Pulp as well as senior content editor and endodontic subject matter expert for newMentor’s series of dental continuing education CD-ROMs and Internet educational services. He is a diplomate of the American Board of Endodontics and has held leadership positions in all of the major professional and academic organizations in endodontics. He maintains a full-time endodontics practice in San Francisco, where he has practiced since 1969. From 1970 until 1988, Dr. Cohen served as chairman of the Department of Endodontics at the University of the Pacific School of Dentistry; and he has continued his involvement with UOP as an adjunct clinical professor of endodontics.
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Traumatic injuries are a common cause of pulpal damage in anterior teeth. Crown fractures with exposed pulps represent 18 percent to 20 percent of the traumatic injuries that involve the teeth. This clinical study comprised 36 patients, who were referred for 40 crown fractures with pulp exposures. There were 39 maxillary incisors and one mandibular incisor. The partial pulpotomy (Cvek’s technique) consists of amputating exposed pulp tissue to a depth of 1 to 2 mm below the point of pulp exposure. After partial pulpotomy, the pulpal wound is covered with calcium hydroxide; and the cavity is sealed with glass ionomer cement or a composite crown. Clinical and radiographic assessment of the hard tissue barrier was done after three months. Patients were monitored for periods ranging from one to 12 years. The purpose of this clinical report was to evaluate Cvek’s technique in the management of coronal fractures with pulp exposures and the long-term outcome of the partial pulpotomy in immature and mature teeth. In virtually all of the cases, this treatment was successful. Careful partial pulpotomy remains a prudent treatment choice with proper case selection.
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Traumatic injuries are a common cause of pulpal damage in anterior teeth. Crown fractures with exposed pulps occur in 18 percent to 20 percent of traumatic injuries involving the teeth.1 These traumatic injuries must be managed correctly for complete pulp repair. Most dental trauma occurs in recently erupted or young permanent teeth that have immature roots;1-4 for this reason the goal of prudent treatment is to preserve normal pulp function. The partial pulpotomy (Cvek’s technique)5 provides dentists with an effective alternative to complete endodontic therapy. It consists of the clean amputation of the exposed pulp tissue to a depth of 1 to 2 mm within dentin of the pulp chamber. After pulpotomy, the pulpal wound is covered with calcium hydroxide powder; then the prepared cavity is sealed with a glass ionomer cement or a composite crown.
The size of the pulp exposure, the time elapsed between the accident and treatment, and the maturity of the roots are important but not critical factors for the long-term success of this treatment.5-8 The purpose of this clinical report was to evaluate the outcome of the partial pulpotomy technique in 36 patients with 40 coronal fractures with exposed pulps. The followups ranged from one year to 12 years.
Material and Methods
The clinical study comprised 36 patients (26 males, 10 females), ranging in age from 6 to 42 years, who were referred for 40 vital permanent incisors with complicated fractures, 39 in maxillary incisors and one in a mandibular incisor. Twenty-one teeth had open apices, and 19 had mature apices. Two maxillary central incisors presented crown-root fractures with exposed pulps (Figures 1a through g and 2a through g).
Preoperative examination revealed that the exposed pulp tissue of two immature incisors had been previously covered with a zinc-oxide-eugenol cement. Because direct contact between ZOE cement and exposed pulp tissue produces predictable inflammation,9 a partial pulpotomy was performed in both teeth (Figures 3a through k).
The time elapsed between the accident and dental treatment ranged from one hour to four days: Five teeth were treated within one to three hours; 21 teeth were treated after two days; one tooth was treated after three days; and 11 teeth were treated after four days (Figures 3a through k, Figures 4a through f, and Figures 5a through f). Only one case had to be treated three months after the accident.
Following local anesthesia and rubber dam isolation, the pulp exposures were cleaned with copious sterile saline solution; pulps were amputated to a depth of 1 to 2 mm within dentin with a new, sterile round diamond bur #.010 or #.012 in a high-speed turbine with copious water-cooling.
Bleeding was controlled by flushing continuously with a sterile saline solution to avoid clot formation. Calcium hydroxide powder was passively applied over the pulpal wound with a sterile amalgam carrier with a small lumen and gently compacted with a sterile cotton pellet moistened with sterile saline (Figures 3a through k).
The partial pulpotomy cavities were sealed in four teeth with a ZOE cement, in 17 with a glass ionomer cement, and in 19 with a metal crown specially manufactured with a small facial opening to permit vitality testing.
Results
The teeth were examined clinically and radiographically after seven, 15, 30, 60, and 90 days. In 39 teeth, the temporary restoration was removed after three months. A hard-tissue dentinal barrier was formed in all 40 teeth and was covered with calcium hydroxide cement (Dycal, Caulk Dentsply, Milford, Del.). Then all teeth were permanently restored with a glass ionomer cement covered with a composite. One tooth was monitored only radiographically, because after partial pulpotomy the tooth was immediately restored with a glass ionomer cement and composite (Figures 6a through c). Follow-up periods ranged from one to 12 years. At each follow-up visit, periapical radiographs were exposed along with electric pulp testing. All teeth were re-examined after one year; 34 teeth were re-examined after four years; and six teeth were closely followed for 12 years. Pulp repair was considered to have occurred according to Cvek’s criteria when the teeth:
* Remained asymptomatic;
* Showed no radiographic evidence of intra- or periradicular pathologic degeneration;
* Showed complete root development in immature teeth; and
* Retained normal pulp sensitivity.
Followups should continue as long as possible (Figures 3a through k and 6a through c).
Under the conditions of this study, pulp repair was completely successful in almost every tooth treated; one tooth failed due to a severe luxation injury.
There was no observable difference between immature or mature teeth in terms of pulp repair. The time elapsed between the accident and dental treatment was not critical for success.10-11 All teeth showed radiographic evidence of dentin bridge formation.
Discussion
Patients with complicated coronal fractures were referred for dental emergency care at different periods following the trauma. Thus, the exposed pulps revealed either a fresh wound or proliferative changes (Figures 7a through f). The inflammatory changes in the pulp tissue in this time interval are superficial.5 Only 1 to 2 mm of the pulp should be removed to cover the non-inflamed pulp with calcium hydroxide because the inflammatory changes in the pulp are superficial (i.e., 1 to 2 mm).5
Partial pulpotomy has distinct advantages because the amputation of only the pulp horn is minimal, thereby permitting the preservation of the cell-rich coronal pulp tissue, a necessary element for healing and preserving the physiological apposition of dentin in the coronal area.12-14 By contrast, the cervical pulpotomy removes all coronal pulp tissue; and the coronal area remains without dentin apposition, thereby increasing the risk of cervical fracture.4 Furthermore, pulp capping might be an alternative treatment in certain types of crown fractures with exposed pulps; but it too has limitations, i.e., the time elapsed between the accident and the dental treatment must be very prompt -- not more than a few hours after accident.15-18 When exposed pulps present with a clot, the clot must be carefully removed because calcium hydroxide should not be placed over a blood clot12-13 (Figure 1e). Another advantage of partial pulpotomy (compared with pulp capping) is better retention of the dressing material.15
In partial pulpotomy, the time of exposure is a secondary factor, because the pulp has rich vascularization and produces a robust defense reaction against bacterial contamination.19-20 As stated earlier, one cause of failure could be severe luxation of the tooth, with the disruption in the blood supply to the pulp. Another cause of failure could be microleakage, because it produces bacterial contamination in pulp tissue ending in pulp necrosis.21 Still another cause of failure for partial pulpotomy could be an incorrect diagnosis of pulp vitality.
The material used over the fresh pulp wound is calcium hydroxide powder. Calcium hydroxide enables formation of a thin layer of coagulation necrosis because Ca(OH)2 exerts a low-grade irritation on the pulp sufficient to stimulate the formation of hard tissue barrier.22-23 A radiograph exposed after seven days shows early dentinal barrier formation (Figure 4c); a complete dentinal barrier was observed at three months.20
Recently, some other studies recommended different materials such as mineral trioxide aggregate24 to stimulate a dentinal bridge after pulp amputation. Although these studies are encouraging, more longitudinal information will be needed before these newer materials can be adopted.25
The size of the exposure, the time elapsed between the accident and the treatment, and the maturity of the roots are not critical factors in selecting the partial pulpotomy. Because some variables (e.g., size of the pulp exposure initially) are not recorded, this type of study does not allow for a reasonable statistical analysis.
The long-term observations of the teeth treated with Cvek’s partial pulpotomy technique appear to result in a successful permanent treatment.
Clinical and histological findings confirm that the partial pulpotomy is a successful permanent treatment in both immature and mature teeth.20
References
1. Andreasen JO, Lesiones Traumáticas de los Dientes, 2nd ed. Labor, Barcelona, 1984, pp 26-34.
2. Andreasen JO, Challenges in clinical dental traumatology. Endont Dent Traumatol 1:45-55, 1985.
3. Andreasen JO, Andreasen FM, Lesiones Dentarias Traumáticas. Editorial Médica Panamericana, Madrid, 1990, pp 35-42.
4. Blanco L, Fracturas coronarias con exposición pulpar. Tratamiento Rev Esp Endod 7:155-60, 1989.
5. Cvek M, A clinical report on partial pulpotomy and capping with calcium hydroxide in permanent incisors with complicated crown fracture. J Endod 4:232-7, 1978.
6. Cvek M, Cleaton Jones P, et al, Pulp reactions to exposure after experimental crown fractures or grinding in adult monkeys. J Endod 8:391-7, 1982.
7. Cvek M, Partial pulpotomy in crown fracture incisors: results 3 to 15 years after treatment. Acta Stomatol Croat 27:167-73, 1993.
8. Cvek M, Coronal tooth injuries: hard and soft tissue management. In, Proceedings of the International Conference on Oral Trauma. American Association of Endodontists, Chicago, 1986, pp 19-54.
9. Holland R, de Mello W, et al, The influence of the sealing material in the healing process of inflamed pulps capped with calcium hydroxide or zinc oxide-eugenol cement. Acta Odontol Pediatr 1:5-9, 1981.
10. Cvek M, Calcium hydroxide in treatment of traumatized teeth. Rev Fr Endod 8(3):11-27, 1989.
11. Cvek M, Partial pulpotomy in crown fractured incisors-results 3 to 15 years after treatment. Acta Stomatol Croat 27:167-73, 1993.
12. Seltzer S, Bender IB, Pulpa Dental. El Manual Moderno, México, 1987, pp 197-8.
13. Avery J, Repair potential of the pulp. J Endod 7:205-12, 1981.
14. Fusk AB, Chosak A, et al, Partial pulpotomy as a treatment alternative for exposed pulps in crown fractured permanent incisors. Endod Dent Traumatol 3:100-2, 1987.
15. Cohen S, Burns RC, eds, Pathways of the Pulp, 4th ed. Mosby Co, St. Louis, 1983, pp 628-9.
16. Fusk AB, Bielak S, Chosak A, Clinical and radiographic assessment of direct pulp capping and pulpotomy in young permanent teeth. Pediatric Dentistry 4:240-4, 1982.
17. Trosntad L, Mjör YA, Capping of the inflamed pulp. Oral Surg Oral Med Oral Pathol 34:240-4, 1972.
18. Stanley HR, Pulp capping: conserving the dental pulp. Oral Surg Oral Med Oral Pathol 68:628-39, 1989.
19. Fusk AB, Gavra S, Chosak A, Long-term follow-up of traumatized incisors treated by partial pulpotomy. Pediatr Dent 15:334-6, 1993.
20. de Blanco LP, Treatment of crown fractures with pulp exposure. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 82:564-8, 1996.
21. Pashley DH, Clinical considerations of microleakage. J Endod 16:70-7, 1990.
22. Cvek M, Granath L, et al, Hard tissue barrier formation in pulpotomized monkey teeth capped with cyanocrylate or calcium hydroxide for 10 and 60 minutes. J Dent Res 66:1166-74, 1987.
23. Cvek M, Calcium Hydroxide in Paediatric Dentistry. Scand Dent AB, Stockholm, 1992.
24. Torabinejad M, Chivian N, Clinical applications of mineral trioxide aggregate. J Endod 25:197-205, 1999.
25. Gao Y, Fang YR, et al, Induction of reparative dentin formation in dogs by bovine bone morphogenetic protein bound to ceramic dentin. J Osaka Dent Univ 29.29-38, 1995.
To request a printed copy of this article, please contact: Stephen Cohen, MA, DDS, 360 Post St., Suite 400, San Francisco, CA 94108 or scohen@newmentor.com.
Figure 1a. Complicated distal crown fracture and incisal fracture in maxillary left incisor in 8-year-old boy three hours after accident. Facial view.
Figure 1b. Palatal view.
Figure 1c. Preoperative radiograph.
Figure 1d. Extraction of the fractured piece.
Figure 1e. After extraction, the exposed pulp tissue presents a little hemorrhage with a clot.
Figure 1f. After removal of restoration, a hard tissue barrier is observed, three months after partial pulpotomy.
Figure 1g. Radiograph three months after partial pulpotomy, pulp continued normal function.
Figure 2a. Complicated vestibular crown-root fracture in maxillary right incisor and uncomplicated vestibular fracture in maxillary left incisor, in 13-year-old girl 36 hours after accident. Facial view.
Figure 2b. Palatal view.
Figure 2c. Preoperative radiograph.
Figure 2d. After extraction of fractured portion, the exposed pulp shows some bleeding.
Figure 2e. Hard-tissue barrier three months after partial pulpotomy.
Figure 2f. Postoperative radiograph.
Figure 2g. Follow-up three years after partial pulpotomy, the pulp continued normal function and responded within normal range to thermal and electric pulp tests.
Figure 3a. Complicated crown fracture in maxillary left incisor and uncomplicated fracture in maxillary right incisor, in 7-year-old girl four days after accident. Maxillary right incisor showing a celluloid crown cemented with zinc-oxide eugenol cement.
Figure 3b. Preoperative radiograph.
Figure 3c. The exposed pulp shows surface clinical necrosis (there was direct contact with zinc-oxide eugenol.
Figure 3d. Preoperative radiograph without crown.
Figure 3e. Partial pulpotomy performed, the amputation was deeper.
Figure 3f. Calcium hydroxide powder applied over the pulp wound.
Figure 3g. Postoperative radiograph.
Figure 3h. Metal crown cemented with an opening to permit vitality testing.
Figure 3i. Radiograph showing the hard tissue barrier (arrow).
Figure 3j. Removal of the metal crown showing hard-tissue barrier three months after partial pulpotomy.
Figure 3k. Follow-up 10 years after partial pulpotomy, the radiograph showing normal function of the pulp in left incisor, the patient had a second accident, with a severe luxation in the right incisor, showing the endodontic therapy.
Figure 4a. Complicated fracture in maxillary left central incisor in 9-year-old boy, two days after accident. The appearance of the exposed pulp.
Figure 4b. Preoperative radiograph.
Figure 4c. Radiograph seven days after partial pulpotomy, showing initial hard-tissue barrier (arrow).
Figure 4d. Radiograph three months after partial pulpotomy.
Figure 4e. Clinical aspect of the hard-tissue barrier.
Figure 4f. Radiograph three years after partial pulpotomy, showing a line of hard-tissue barrier into the canal.
Figure 5a. Complicated fracture in maxillary left central incisor in 10-year-old boy two days after accident. The hemorrhage pulp can be seen through the dentin (arrow).
Figure 5b. Preoperative radiograph showing the apex of the maxillary left central incisor with the apex more open than the right central incisor.
Figure 5c. Pulpotomy performed.
Figure 5d. Bleeding controlled.
Figure 5e. Clinical aspect of the hard-tissue barrier.
Figure 5f. Radiograph 3½ years after partial pulpotomy, the apex continued to mature and the pulp retained normal function.
Figure 6a. Complicated fracture in maxillary left incisor and uncomplicated fracture in maxillary right incisor in 42-year-old woman, two hours after accident. Photograph of the exposed pulp.
Figure 6b. Radiograph of the exposed pulp (arrow).
Figure 6c. Radiograph 12 years after partial pulpotomy and restoration. There are no pathologic changes.
Figure 7a. Complicated fracture in maxillary right central incisor in 12-year-old girl, two hours after accident. View of the exposed pulp.
Figure 7b. Another view of the exposed pulp revealing proliferate changes and hemorrhage.
Figure 7c. Preoperative radiograph.
Figure 7d. View of the hard-tissue barrier three months after partial pulpotomy.
Figure 7e. Another view of the hard-tissue barrier three months after partial pulpotomy.
Figure 7f. Radiograph six months after partial pulpotomy.
