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Iatrogenic perforation of the roots of restoration-covered teeth
Iatrogenic perforation of the roots of restoration-covered teeth Z. Metzger, DMD, and I. Shperling, DMD
Perforation of the root is one of the most frustrating complications of endodontic treatment. T h e c o m m o n causes of perforations are failure to detect a bend of the root or root canal; overinstrumentation in the concave side of a curved root; an a t t e m p t to overcome a ledge formed either in the process of the current or in a previous endodontic treatment; or an attempt to open a pulp chamber or root canal obstructed by calcification ~-~ Most of these perforations are located in the apical area of the root and are caused by instrumentation in radiographically undetectable anatomical variations in the shape of the a p i c a L p a r t of the root and root canal. I T h e periapical radiograph is the most useful source of information regarding the shape o f the root and root canal. However, the information it provides about the a n a t o m y in the buccolingual plane is limited. Familiarity with the c o m m o n and uncomm o n variations of the a n a t o m y of the root is needed to successfully perform endodontic treatment. Locating the root canal in teeth with obstructions in the pulp c h a m b e r or root canal presents a special problem. This problem becomes more severe when the tooth is covered by a restoration, because anatomical landmarks, which can be helpful, m a y not be located in their original location relative to the root. These cases particularly call for an additional source of
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information, namely, the shape of the alveolar process over the root and the a n a t o m y of the root surface in the cervical area below the m a r g i n of the restoration. T h e purpose of this case report is to demonstrate a case in which the radiograph and the a n a t o m y o f the crown were the only sources of information; failure to observe the anatom y of the alveolar process led to a perforation of the root. CASE REPORT A 29-year-old white w o m a n was referred for possible endodontic therapy of two maxillary central incisors. T h e patient was in good health with no significant medical history. T h e patient had been treated the previous three months for two persistent sinus tract infections, which appeared in the area of the maxillary central incisors shortly after an a t t e m p t to replace root canal fillings. T h e teeth were a s y m p t o m a t i c with no unusual radiographic findings before the attempt to replace the root canal fillings. T h e most recent procedure had been performed in preparation for the construction of posts and cores for new crowns. Visual examination showed two maxillary central incisors with veneer crowns, having small access cavities on their lingual surface. T w o sinus tracts were observed in the vestibular mucosa in the region o f
the involved teeth. The teeth were not sensitive to percussion, and no mobility was detected. Slight gingivitis was present at the margins of the crowns; however, no periodontal pocket was observed. O n examination of the vestibulum, it became clear that the long axis of the veneer crowns did not reflect the long axis of the root (Fig 1). W h e n the patient was asked the reason for the construction of the first crowns, she replied that the protrusions of the maxillary central incisors were esthetically disturbing and had been corrected by veneer crowns. A radiograph showed poorly condensed root canal fillings, but no periapical radiolucent areas were seen. T h e tentative diagnosis was buccal perforation of the roots caused by following the misleading a n a t o m y of the veneer crowns. T h e area was isolated by rubber d a m ; no. 15 files were inserted into the root canals. T h e protrusion of the instruments through the sinus tracts confirmed the diagnosis. Appropriate endodontic access cavities were prepared, which in this case extended to the incisal edge of the crowns (Fig 1). After removal of the poorly condensed root canal fillings, the canals were prepared and obturated using the lateral condensation technique with AH-26 and gutta-percha. Retrograde a m a l g a m fillings were considered for the closure of the perforations, Because a rela-
JOURNAL OF ENDODONTICS I VOL 7, NO 5, MAY 1981
I I I I
1
t
Fig /--Schematic presentation of buccolingual section of involved teeth. Anatomy of crown has been changed for esthetic reasons. Long axis of crown does not represent long axis of root and led to perforation.
Fig 2-Clinical view at time of surgery.
Fzg 3--Clinical view at 12-month recall.
of g u t t a - p e r c h a (Fig 2) were cut flat by a hot instrument. Five days later, the sutures were removed; the sinus tracts were already closed a n d healing. As no symptoms reappeared t h r o u g h the next six months, new posts, cores, a n d crowns were constructed. At the 12-month recall (Fig 3), the teeth were asymptomatic.
would provide a clear, u n o b s t r u c t e d approach to the pulp c h a m b e r a n d root canals. A n a t t e m p t to save the restoration by limiting the size of the o p e n i n g may, in some cases, result in the loss of both the tooth a n d the restoration.
DISCUSSION tively large area of alveolar mucosa was exposed when the p a t i e n t smiled, including the area of the sinus tracts, a n d a possible discoloration of the muscosa by the a m a l g a m :~ could have resulted in a n unesthetic appearance, retrograde a m a l g a m s were not placed. Each false canal was prepared to a g r a d u a l convergence, avoiding e n l a r g m e n t of the apical orifice. An i n d i v i d u a l g u t t a - p e r c h a cone was prepared by repeating the procedure of softening its surface with chloroform, inserting it into the canal, removing it, a n d letting it harden on the tray t h r o u g h evaporation. The cone a n d the walls of the false canal were coated with AH-26, and the cone was inserted. A better adaptation was achieved by softeniilg the cone in situ by heat a n d applying vertical pressure. Four days later, the area was exposed surgically, and the small p r o t r u d i n g bulges
T h e shape a n d direction of the alveolar bone over the root of a tooth given e n d o d o n t i c t r e a t m e n t provides useful i n f o r m a t i o n a b o u t the direction of the root. T h e buccal aspect of maxillary teeth is particularly informative, as this case demonstrates. I n f o r m a t i o n a b o u t the direction of the alveolar bone becomes i m p o r t a n t in situations in which other a n a t o m ical features, which n o r m a l l y guide the operator are not present, such as the n a t u r a l a n a t o m y of the crown a n d a wide, easily identifiable root canal. T h e a n a t o m y of extracoronal restorations m a y be misleading, both in defining the long axis of the root a n d in locating the pulp c h a m b e r , which m a y be covered by the restoration a n d not a p p a r e n t in the radiograph. In m a n y cases, this calls for a wide e n d o d o n t i c access cavity that
SUMMARY A case of iatrogenic perforations of the roots of two maxillary central incisors, which demonstrates the importance of e x a m i n i n g the alveolar process before e n d o d o n t i c treatment, was presented. The authors thank Dr. J. T. Hoffeld for reviewing the manuscript and Mrs. Y. Mazor for photographic assistance. Dr. Metzger is an instructor in the department of operative dentistry, Tel Aviv University, and is practicing endodontics in Tel Aviv, Israel. Dr. Shperling is an instructor in the department of periodontics, School of Dental Medicine, Tel Aviv, Israel. Requests for reprints should be directed to Dr. Metzger. References
1. Ingle, J.I., and others. Endodontic surgery. In: J. I. Ingle, and E. E. Beveridge (eds.). Endodontics,ed 2. Philadelphia, Lea & Febiger, 1976, pp 594-684. 2. Frank, A. L. Resorption, perforation and fractures. Dent Clio North Am 18(2):465-487, 1974. 3. Weathers, D. R., and Fine, R. M. Amalgam tattoo of oral nmcosa. Arch Dermatol 110(5):727-728, 1974.
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Perforation of the root is one of the most frustrating complications of endodontic treatment. T h e c o m m o n causes of perforations are failure to detect a bend of the root or root canal; overinstrumentation in the concave side of a curved root; an a t t e m p t to overcome a ledge formed either in the process of the current or in a previous endodontic treatment; or an attempt to open a pulp chamber or root canal obstructed by calcification ~-~ Most of these perforations are located in the apical area of the root and are caused by instrumentation in radiographically undetectable anatomical variations in the shape of the a p i c a L p a r t of the root and root canal. I T h e periapical radiograph is the most useful source of information regarding the shape o f the root and root canal. However, the information it provides about the a n a t o m y in the buccolingual plane is limited. Familiarity with the c o m m o n and uncomm o n variations of the a n a t o m y of the root is needed to successfully perform endodontic treatment. Locating the root canal in teeth with obstructions in the pulp c h a m b e r or root canal presents a special problem. This problem becomes more severe when the tooth is covered by a restoration, because anatomical landmarks, which can be helpful, m a y not be located in their original location relative to the root. These cases particularly call for an additional source of
232
information, namely, the shape of the alveolar process over the root and the a n a t o m y of the root surface in the cervical area below the m a r g i n of the restoration. T h e purpose of this case report is to demonstrate a case in which the radiograph and the a n a t o m y o f the crown were the only sources of information; failure to observe the anatom y of the alveolar process led to a perforation of the root. CASE REPORT A 29-year-old white w o m a n was referred for possible endodontic therapy of two maxillary central incisors. T h e patient was in good health with no significant medical history. T h e patient had been treated the previous three months for two persistent sinus tract infections, which appeared in the area of the maxillary central incisors shortly after an a t t e m p t to replace root canal fillings. T h e teeth were a s y m p t o m a t i c with no unusual radiographic findings before the attempt to replace the root canal fillings. T h e most recent procedure had been performed in preparation for the construction of posts and cores for new crowns. Visual examination showed two maxillary central incisors with veneer crowns, having small access cavities on their lingual surface. T w o sinus tracts were observed in the vestibular mucosa in the region o f
the involved teeth. The teeth were not sensitive to percussion, and no mobility was detected. Slight gingivitis was present at the margins of the crowns; however, no periodontal pocket was observed. O n examination of the vestibulum, it became clear that the long axis of the veneer crowns did not reflect the long axis of the root (Fig 1). W h e n the patient was asked the reason for the construction of the first crowns, she replied that the protrusions of the maxillary central incisors were esthetically disturbing and had been corrected by veneer crowns. A radiograph showed poorly condensed root canal fillings, but no periapical radiolucent areas were seen. T h e tentative diagnosis was buccal perforation of the roots caused by following the misleading a n a t o m y of the veneer crowns. T h e area was isolated by rubber d a m ; no. 15 files were inserted into the root canals. T h e protrusion of the instruments through the sinus tracts confirmed the diagnosis. Appropriate endodontic access cavities were prepared, which in this case extended to the incisal edge of the crowns (Fig 1). After removal of the poorly condensed root canal fillings, the canals were prepared and obturated using the lateral condensation technique with AH-26 and gutta-percha. Retrograde a m a l g a m fillings were considered for the closure of the perforations, Because a rela-
JOURNAL OF ENDODONTICS I VOL 7, NO 5, MAY 1981
I I I I
1
t
Fig /--Schematic presentation of buccolingual section of involved teeth. Anatomy of crown has been changed for esthetic reasons. Long axis of crown does not represent long axis of root and led to perforation.
Fig 2-Clinical view at time of surgery.
Fzg 3--Clinical view at 12-month recall.
of g u t t a - p e r c h a (Fig 2) were cut flat by a hot instrument. Five days later, the sutures were removed; the sinus tracts were already closed a n d healing. As no symptoms reappeared t h r o u g h the next six months, new posts, cores, a n d crowns were constructed. At the 12-month recall (Fig 3), the teeth were asymptomatic.
would provide a clear, u n o b s t r u c t e d approach to the pulp c h a m b e r a n d root canals. A n a t t e m p t to save the restoration by limiting the size of the o p e n i n g may, in some cases, result in the loss of both the tooth a n d the restoration.
DISCUSSION tively large area of alveolar mucosa was exposed when the p a t i e n t smiled, including the area of the sinus tracts, a n d a possible discoloration of the muscosa by the a m a l g a m :~ could have resulted in a n unesthetic appearance, retrograde a m a l g a m s were not placed. Each false canal was prepared to a g r a d u a l convergence, avoiding e n l a r g m e n t of the apical orifice. An i n d i v i d u a l g u t t a - p e r c h a cone was prepared by repeating the procedure of softening its surface with chloroform, inserting it into the canal, removing it, a n d letting it harden on the tray t h r o u g h evaporation. The cone a n d the walls of the false canal were coated with AH-26, and the cone was inserted. A better adaptation was achieved by softeniilg the cone in situ by heat a n d applying vertical pressure. Four days later, the area was exposed surgically, and the small p r o t r u d i n g bulges
T h e shape a n d direction of the alveolar bone over the root of a tooth given e n d o d o n t i c t r e a t m e n t provides useful i n f o r m a t i o n a b o u t the direction of the root. T h e buccal aspect of maxillary teeth is particularly informative, as this case demonstrates. I n f o r m a t i o n a b o u t the direction of the alveolar bone becomes i m p o r t a n t in situations in which other a n a t o m ical features, which n o r m a l l y guide the operator are not present, such as the n a t u r a l a n a t o m y of the crown a n d a wide, easily identifiable root canal. T h e a n a t o m y of extracoronal restorations m a y be misleading, both in defining the long axis of the root a n d in locating the pulp c h a m b e r , which m a y be covered by the restoration a n d not a p p a r e n t in the radiograph. In m a n y cases, this calls for a wide e n d o d o n t i c access cavity that
SUMMARY A case of iatrogenic perforations of the roots of two maxillary central incisors, which demonstrates the importance of e x a m i n i n g the alveolar process before e n d o d o n t i c treatment, was presented. The authors thank Dr. J. T. Hoffeld for reviewing the manuscript and Mrs. Y. Mazor for photographic assistance. Dr. Metzger is an instructor in the department of operative dentistry, Tel Aviv University, and is practicing endodontics in Tel Aviv, Israel. Dr. Shperling is an instructor in the department of periodontics, School of Dental Medicine, Tel Aviv, Israel. Requests for reprints should be directed to Dr. Metzger. References
1. Ingle, J.I., and others. Endodontic surgery. In: J. I. Ingle, and E. E. Beveridge (eds.). Endodontics,ed 2. Philadelphia, Lea & Febiger, 1976, pp 594-684. 2. Frank, A. L. Resorption, perforation and fractures. Dent Clio North Am 18(2):465-487, 1974. 3. Weathers, D. R., and Fine, R. M. Amalgam tattoo of oral nmcosa. Arch Dermatol 110(5):727-728, 1974.
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