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Disintegration of two silver cones
CLINICAL ARTICLE
Disintegration of two silver cones William E. Harris, DDS
Two silver cones partially disintegrated between one and seven years a f t e r b e i n g p l a c e d in t h e r o o t c a n a l s o f a m a x i l l a r y m o l a r . T h e disintegration pattern was very unusual. One cone disintegrated from the apex inward, another from the chamber outward, while a third cone was not affected.
Ingle' reported a case in which a stainless-steel file d i s i n t e g r a t e d in the root canal of a m a n d i b u l a r m o l a r in six months. Rust-like residue was o b t a i n e d from the root c a n a l d u r i n g re-treatment. Ingle said, " T h e inadvertently broken i n s t r u m e n t which is loose in the canal with no cement a r o u n d it frequently rusts out within six m o n t h s to a year a n d is no longer a p p a r e n t in the recall roentgenog r a m . " Luks' discovered blackened silver cones and recovered black residue from root canals, which he said h a d been poorly filled with silver cones. Bender ~ stated that he had seen silver cones disintegrate in root canals. I reported the disintegration of a portion of a silver cone that h a d filled the root canal of a maxillary, lateral incisor.' T h a t case a p p e a r s to be the first report of such an event. This current case m a y be only the second. Therefore, d i s i n t e g r a t i o n of a silver cone in a root canal can be considered a rare occurrence. Because of its a p p a r e n t rarity a n d the especially unusual disintegration p a t t e r n of two of three silver cones, the following case is presented.
426
CASE REPORT
History and examination A 41-year-old white w o m a n was referred for t r e a t m e n t by her dentist because she experienced discomfort a n d sensitivity to heat in the maxillary left first molar. This tooth was the posterior a b u t m e n t for a threeyear-old fixed partial d e n t u r e that e x t e n d e d anteriorly to the first 15remolar. T h e m o l a r was t e n d e r to light percussion a n d did not respond to cold. T h e p r e m o l a r was not t e n d e r to precussion and responded n o r m a l l y to cold. T h e r e was m o d e r a t e loss of p e r i o d o n t a l support in the area (Fig 1, top left). A diagnosis of p u l p a l necrosis was made.
Treatment Local anesthetic was a d m i n i s tered, a r u b b e r d a m was placed, an o p e n i n g was m a d e into the c h a m b e r of the molar, a n d a putrescent o d o r was noticed. T h r e e root canals were d e b r i d e d , measured, irrigated, dried, and m e d i c a t e d . Eight days later, the
tooth was not painful; so the root canals were cleaned, shaped, irrigated, dried, a n d m e d i c a t e d Six days after the second visit, the canals were irrigated, dried, and then filled with tightly fitted silver cones and root canal sealer (Fig 1, top right). Tile p u l p c h a m b e r was filled with z i n c - o x y p h o s p h a t e cement, and the access o p e n i n g restored with amalgam.
Recall examination i:ight m o n t h s later, patient reported that she had experienced no discomfort, or o t h e r symptoms, since the first t r e a t m e n t visit. T h e molar area a p p e a r e d n o r m a l on the radiograph (Fig 1, b o t t o m left) except for the loss of p e r i o d o n t a l support previously m e n t i o n e d .
Subsequent examination and treatment T h e patient was referred fi)r treat" ment by her dentist 14 years later because of a d r a i n i n g sinus tract on the gingiva, distal to the maxillary
JOURNAL OF E N D O D O N T I C S
left tirst molar. A gutta-percha point, placed in the stoma of tile sinus tract (Fig 1. bottom right), appeared on the radiograph to terminate near the apexes of the distal and palatal roots of this tooth (Fig 2, top left). The radiograph also showed that the two silver cones in the facial roots were undergoing disintegration; whereas, the silver cone in the palatal root appeared to be still intact. T h e pattern of disintegration was unusual; the silver cone in lhe distal facial root canal had disintegrated from the chamber apically, leaving only the apical 2 to 3 mrn of the root canal filling intact. Conversely, the silver cone in the mesial root canal had disintegrated from the apex inward, leaving only the coronal 3 to 4 mm of the root canal filling intact. The silver cone in the palatal root canal appeared to be unatfected The 0cclusal amalgam restoration, placed after endodontic treatment 14 years earlier, was still intact (Fig 2, top right). The loss of periodontal support had progressed somewhat over the years, but not extensively. The diagnosis was a chronic apical abscess, with draining sinus tract. The patient was informed that retreatment of the root canals should be performed or that the fixed partial denture should be sectioned distal to the premolar, and the molar extracted. 'l'hc patient chose retreatrnent and appeared to be sincerely interested in preserving the tooth and the fixed partial denture. A ruhber dam was placed, and the amalgam and cement were removed so that the root canals could be examined. Black residue was obtained from the facial root canals in the areas where the silver cones had Undergone disintegration (Fig 2, bottom left). The remainder of the silver e0ne ira the apical portion of the
VOL 7, N O 9, SEPTEMBER 1981
b)g 1-7"o/) left, preoperatzve radzograph showmg fixed partial denture abutments and moderate loss of perzodontal support. Top right, completion #'root canal treatment. Bottom left, eightmonth recall radiograph. Bottom right; seven years after completwn of root canal treatment. Disintegration of sth,er cones in facial root canals is evident.
Fig 2. Top left, eleven.rears after completwn of root canal treatment. Disintzeration of silver cones ts progressing. Top rzght, gutta-percha point in stoma of draining sinus tract fourteen years r completzon of root canal treatment. Bottom left, gutta-percha point terminates near apexes of distal and palatal roots.
427
JOURNAL OF ENDODONTICS I VOL 7, NO 9, SEPTEMBER 1981
Ftg 3-Left, amalgam filling placed at initial treatment remains intact after 14years. Middle, black debrts rernouedfrom areas of s~lwer cone &sintegration in facial root canals. Right, silver cone removedfrom palatal root canal is unaffected by dismtegratzon process.
distal-facial root canal could not be bypassed or dislodged, and appeared to continue to seal the apex. The silver cone removed from the palatal root canal was intact (Fig 3, left). All root canals were debrided, enlarged, shaped, irrigated, and medicated. T h e patient was given an appointment to return in nine days to have all the root canals filled with guttapercha and root canal sealer. T h e patient did not return, however. Since then, she has refused to have further examination or treatment despite having been contacted several times. Sixteen months later, a report concerning the maxillary left first molar was obtained from the patient's periodontist. He said that the gingiva in the affected area appeared to be normal; there was no draining sinus tract, the occlusal cement seal was intact, and the gingival sulcus around the molar was intact and of normal depth. T h e patient refused to have any radiographic examination of her teeth during this visit to her periodontist.
Report from the referring dentist T h e referring dentist furnished radiographs, which he had taken
428
seven and 11 years after endodontic treatment (Fig 1, bottom left, and Fig 3, middle). Disintegration of the t~tcial silver cones can be seen in Figure 3, middle. Figure 3, right, shows continued, progressive, disintegration of the silver cones in both facial canals. These radiographs indicate that the disintegration began between one and seven years after endodontic treatment. T h e dentist also reported an episode that occurred five years after endodontic treatment, during which the patient experienced a reaction to a newly constructed removable m a n d i b u l a r partial denture made of cast chromecobalt alloy. The patient noticed a burning sensation in her tongue and buccal mucosa soon after this denture was inserted. These s y m p t o m s would subside when the denture was removed and left out of the mouth, but they would reappear after the denture was reinserted and worn for a day or two. Later, it was discovered that the symptoms would not a p p e a r if the denture was coated with Copalite before it was inserted. However, this remedy was temporary, and the symptoms would return within a week, as the Copalite wore otL T h e patient continued to wear this denture tot about two months, but the symptoms persisted. There-
fore, the denture was discarded and replaced by one made of cast-gold alloy. No adverse symptoms were experienced by the patient after the new denture was inserted. DISCUSSION Perhaps the symptoms noticed by the patient during the time she attempted to >,ear the chrome-cobalt denture were related to galvanic current, and this current contributed to the disintegration of the silver cones. However, when the denture was replaced with a gold one the symptoms disappeared. Nevertheless. the radiographs in Figure 3. middle and right, show that the disintegration continued for several years after the first denture was discarded. This would indicate that if the disintegration had been initiated by a galvanic current generated from dissimilar metals, it continued long after the current presumably stopped, perhaps these two events were not related, but they did present an interesting coincidence. Also, a reaC" tion to a chrome-cobalt denture, such as this patient experienced, was considered unusual. Perhaps, galvanic current was pr0duced by the dissimilar metals of the silver cones and the gold full croW~'.
IOURNAL OF E N D O D O N T I C S ~ VOE 7, N O 9, SEPTEMBER 1981
],lowever, this seems unlikely as the ~etals were not in direct contact, ~ d they were presumably well-insul t e d from one a n o t h e r by the zincoxyphosphate cement in the pulp ~amber. The possibility was considered that an untilled second root canal in the mesiofacial root might have contributed to the disintegration of the silver cones. T h e frequency of occurfence of two root canals in the mesiofacial roots of maxillary molars has been reported to be almost 70%? A diligent, but unsuccessful effort was made to find a second root canal in the mesiofacial root of the molar during both the initial e n d o d o n t i c treatment a n d re-treatment 14 years later. If a second root canal had been present and leakage t h r o u g h its unfilled space had c o n t r i b u t e d to the disintegration of these silver cones, it would seem that the p a t t e r n of disintegration would have been the same in all root canals, that is, from the chamber apically. Therefore, because this did not occur a n d no second root canal was found, it was mncluded that no second root canal existed in the mesial root of this tooth. The pattern of disintegration in this case was unusual: one silver cone disintegrated from the apex inward, and another from the c h a m b e r outward; whereas, the third was unaffected. If disintegration of silver runes were to occur in the root canals 0fa tooth, it would seem logical that it would occur from the apex inward and not from the c h a m b e r outward. This disintegration from the apex inward would be expected if it were Presumed that the apical seal was deficient, which was p r o b a b l y the
case in the mesial root canal of this tooth. T h e pulp c h a m b e r of the tooth was sealed from the oral envir o n m e n t with dental cement, which was found to be intact years later. Therefore, it is puzzling that the disintegration began within the c h a m b e r a n d progressed o u t w a r d , leaving a portion of intact silver cone in the apex of one root, unless a c o m m u n i c a t i o n existed from the outside of the tooth into the pulp c h a m ber. If this had been the case, then the question arises as to why the other two silver cones were not similarly affected. Even more puzzling was the presence of an intact portion of silver cone, leading into the mesial canal, directly adjacent to the area of the p u l p c h a m b e r c o n t a i n i n g the coronally disintegrated distal silver cone, However, 1 believe the failure of this case cannot be a t t r i b u t e d to the filling material used, but to other factors. Such a factor could be the probable lack of apical seal in the mesial root canal, allowing the apical portion of this silver cone to corrode and then disintegrate from the apex inward. Also, there might have been a c o m m u n i c a t i o n , via an accessory canal in the furcation of this tooth, between the pulp c h a m b e r a n d the oral e n v i r o n m e n t despite d e n t a l cement filling the pulp c h a m b e r a n d p r e s u m a b l y s u r r o u n d i n g the silver cones. This could explain how corrosion a n d then disintegration of the distal silver cone took place fi'om the c h a m b e r apically. However, the exp l a n a t i o n fails to account for the existence, in proximity, of an unaffected portion of silver cone leading into the mesial root canal a n d an unaffected silver cone in the palatal root canal. T h e above speculations,
and that ing the add
any other points of conjecture the reader m i g h t have, concernthe circumstances a n d cause of e n d o d o n t i c failure of this case to its interest.
SUMMARY A rare instance of disintegration of two silver cones in a maxillary molar made more u n u s u a l because of dissimilar disintegration patterns a n d a n unaffected third silver cone in the same tooth, has been presented. Photographs were taken by the Department of Audio-Visual Services, Emory University School. This case was presented before the annual meeting of the Georgia Associationof Endodontists. Charlotte Amalie, St. Thomas, VI. Oct 8, 1978. The author thanks Dr. Worth Gregory, .Jr., for his help in reviewing the manuscript. Dr. Harris is an endodontist in private practice, tie is also clinical associate, endodontics, Emory University School of l)entistry, Atlanta, and is on the teaching staff in endodontics, Medical College of G-eorgia,School of Dentistry', Augusta. He is chief of cndodnntic sen'ices and director of off-site clinical training, Mas.sell Dental Clinic, Atlanta. Request for reprints should be directed to the author, 401 Peachtree St NE, Atlanta, 30308. References
l. Ingle,J.l., and Beveridge, E.E. Endodontics, ed 2. Philadelphia, I,ea & Febiger, 1976, 255. 2. Luks, S., Gutta-percha versus silver points in the practice ofendodontics. NY Dent J 31:341, 1965. 3. Bender, 1.B. Clinical presentation. Presented at the Southern Endodontic Study Group annual meeting, Williamsburgh, Va, July 1970. 4. Harris, W.E. Disintegration of a silver point: report of case. JADA 83:868, 1971. 5. Acousta Vigouroux, S., and Trugeda Bosaans, S. Anatomy of the pulp chamber of the permanent maxillary,first molar. J Endod 4(7):214, 1978.
429
Disintegration of two silver cones William E. Harris, DDS
Two silver cones partially disintegrated between one and seven years a f t e r b e i n g p l a c e d in t h e r o o t c a n a l s o f a m a x i l l a r y m o l a r . T h e disintegration pattern was very unusual. One cone disintegrated from the apex inward, another from the chamber outward, while a third cone was not affected.
Ingle' reported a case in which a stainless-steel file d i s i n t e g r a t e d in the root canal of a m a n d i b u l a r m o l a r in six months. Rust-like residue was o b t a i n e d from the root c a n a l d u r i n g re-treatment. Ingle said, " T h e inadvertently broken i n s t r u m e n t which is loose in the canal with no cement a r o u n d it frequently rusts out within six m o n t h s to a year a n d is no longer a p p a r e n t in the recall roentgenog r a m . " Luks' discovered blackened silver cones and recovered black residue from root canals, which he said h a d been poorly filled with silver cones. Bender ~ stated that he had seen silver cones disintegrate in root canals. I reported the disintegration of a portion of a silver cone that h a d filled the root canal of a maxillary, lateral incisor.' T h a t case a p p e a r s to be the first report of such an event. This current case m a y be only the second. Therefore, d i s i n t e g r a t i o n of a silver cone in a root canal can be considered a rare occurrence. Because of its a p p a r e n t rarity a n d the especially unusual disintegration p a t t e r n of two of three silver cones, the following case is presented.
426
CASE REPORT
History and examination A 41-year-old white w o m a n was referred for t r e a t m e n t by her dentist because she experienced discomfort a n d sensitivity to heat in the maxillary left first molar. This tooth was the posterior a b u t m e n t for a threeyear-old fixed partial d e n t u r e that e x t e n d e d anteriorly to the first 15remolar. T h e m o l a r was t e n d e r to light percussion a n d did not respond to cold. T h e p r e m o l a r was not t e n d e r to precussion and responded n o r m a l l y to cold. T h e r e was m o d e r a t e loss of p e r i o d o n t a l support in the area (Fig 1, top left). A diagnosis of p u l p a l necrosis was made.
Treatment Local anesthetic was a d m i n i s tered, a r u b b e r d a m was placed, an o p e n i n g was m a d e into the c h a m b e r of the molar, a n d a putrescent o d o r was noticed. T h r e e root canals were d e b r i d e d , measured, irrigated, dried, and m e d i c a t e d . Eight days later, the
tooth was not painful; so the root canals were cleaned, shaped, irrigated, dried, a n d m e d i c a t e d Six days after the second visit, the canals were irrigated, dried, and then filled with tightly fitted silver cones and root canal sealer (Fig 1, top right). Tile p u l p c h a m b e r was filled with z i n c - o x y p h o s p h a t e cement, and the access o p e n i n g restored with amalgam.
Recall examination i:ight m o n t h s later, patient reported that she had experienced no discomfort, or o t h e r symptoms, since the first t r e a t m e n t visit. T h e molar area a p p e a r e d n o r m a l on the radiograph (Fig 1, b o t t o m left) except for the loss of p e r i o d o n t a l support previously m e n t i o n e d .
Subsequent examination and treatment T h e patient was referred fi)r treat" ment by her dentist 14 years later because of a d r a i n i n g sinus tract on the gingiva, distal to the maxillary
JOURNAL OF E N D O D O N T I C S
left tirst molar. A gutta-percha point, placed in the stoma of tile sinus tract (Fig 1. bottom right), appeared on the radiograph to terminate near the apexes of the distal and palatal roots of this tooth (Fig 2, top left). The radiograph also showed that the two silver cones in the facial roots were undergoing disintegration; whereas, the silver cone in the palatal root appeared to be still intact. T h e pattern of disintegration was unusual; the silver cone in lhe distal facial root canal had disintegrated from the chamber apically, leaving only the apical 2 to 3 mrn of the root canal filling intact. Conversely, the silver cone in the mesial root canal had disintegrated from the apex inward, leaving only the coronal 3 to 4 mm of the root canal filling intact. The silver cone in the palatal root canal appeared to be unatfected The 0cclusal amalgam restoration, placed after endodontic treatment 14 years earlier, was still intact (Fig 2, top right). The loss of periodontal support had progressed somewhat over the years, but not extensively. The diagnosis was a chronic apical abscess, with draining sinus tract. The patient was informed that retreatment of the root canals should be performed or that the fixed partial denture should be sectioned distal to the premolar, and the molar extracted. 'l'hc patient chose retreatrnent and appeared to be sincerely interested in preserving the tooth and the fixed partial denture. A ruhber dam was placed, and the amalgam and cement were removed so that the root canals could be examined. Black residue was obtained from the facial root canals in the areas where the silver cones had Undergone disintegration (Fig 2, bottom left). The remainder of the silver e0ne ira the apical portion of the
VOL 7, N O 9, SEPTEMBER 1981
b)g 1-7"o/) left, preoperatzve radzograph showmg fixed partial denture abutments and moderate loss of perzodontal support. Top right, completion #'root canal treatment. Bottom left, eightmonth recall radiograph. Bottom right; seven years after completwn of root canal treatment. Disintegration of sth,er cones in facial root canals is evident.
Fig 2. Top left, eleven.rears after completwn of root canal treatment. Disintzeration of silver cones ts progressing. Top rzght, gutta-percha point in stoma of draining sinus tract fourteen years r completzon of root canal treatment. Bottom left, gutta-percha point terminates near apexes of distal and palatal roots.
427
JOURNAL OF ENDODONTICS I VOL 7, NO 9, SEPTEMBER 1981
Ftg 3-Left, amalgam filling placed at initial treatment remains intact after 14years. Middle, black debrts rernouedfrom areas of s~lwer cone &sintegration in facial root canals. Right, silver cone removedfrom palatal root canal is unaffected by dismtegratzon process.
distal-facial root canal could not be bypassed or dislodged, and appeared to continue to seal the apex. The silver cone removed from the palatal root canal was intact (Fig 3, left). All root canals were debrided, enlarged, shaped, irrigated, and medicated. T h e patient was given an appointment to return in nine days to have all the root canals filled with guttapercha and root canal sealer. T h e patient did not return, however. Since then, she has refused to have further examination or treatment despite having been contacted several times. Sixteen months later, a report concerning the maxillary left first molar was obtained from the patient's periodontist. He said that the gingiva in the affected area appeared to be normal; there was no draining sinus tract, the occlusal cement seal was intact, and the gingival sulcus around the molar was intact and of normal depth. T h e patient refused to have any radiographic examination of her teeth during this visit to her periodontist.
Report from the referring dentist T h e referring dentist furnished radiographs, which he had taken
428
seven and 11 years after endodontic treatment (Fig 1, bottom left, and Fig 3, middle). Disintegration of the t~tcial silver cones can be seen in Figure 3, middle. Figure 3, right, shows continued, progressive, disintegration of the silver cones in both facial canals. These radiographs indicate that the disintegration began between one and seven years after endodontic treatment. T h e dentist also reported an episode that occurred five years after endodontic treatment, during which the patient experienced a reaction to a newly constructed removable m a n d i b u l a r partial denture made of cast chromecobalt alloy. The patient noticed a burning sensation in her tongue and buccal mucosa soon after this denture was inserted. These s y m p t o m s would subside when the denture was removed and left out of the mouth, but they would reappear after the denture was reinserted and worn for a day or two. Later, it was discovered that the symptoms would not a p p e a r if the denture was coated with Copalite before it was inserted. However, this remedy was temporary, and the symptoms would return within a week, as the Copalite wore otL T h e patient continued to wear this denture tot about two months, but the symptoms persisted. There-
fore, the denture was discarded and replaced by one made of cast-gold alloy. No adverse symptoms were experienced by the patient after the new denture was inserted. DISCUSSION Perhaps the symptoms noticed by the patient during the time she attempted to >,ear the chrome-cobalt denture were related to galvanic current, and this current contributed to the disintegration of the silver cones. However, when the denture was replaced with a gold one the symptoms disappeared. Nevertheless. the radiographs in Figure 3. middle and right, show that the disintegration continued for several years after the first denture was discarded. This would indicate that if the disintegration had been initiated by a galvanic current generated from dissimilar metals, it continued long after the current presumably stopped, perhaps these two events were not related, but they did present an interesting coincidence. Also, a reaC" tion to a chrome-cobalt denture, such as this patient experienced, was considered unusual. Perhaps, galvanic current was pr0duced by the dissimilar metals of the silver cones and the gold full croW~'.
IOURNAL OF E N D O D O N T I C S ~ VOE 7, N O 9, SEPTEMBER 1981
],lowever, this seems unlikely as the ~etals were not in direct contact, ~ d they were presumably well-insul t e d from one a n o t h e r by the zincoxyphosphate cement in the pulp ~amber. The possibility was considered that an untilled second root canal in the mesiofacial root might have contributed to the disintegration of the silver cones. T h e frequency of occurfence of two root canals in the mesiofacial roots of maxillary molars has been reported to be almost 70%? A diligent, but unsuccessful effort was made to find a second root canal in the mesiofacial root of the molar during both the initial e n d o d o n t i c treatment a n d re-treatment 14 years later. If a second root canal had been present and leakage t h r o u g h its unfilled space had c o n t r i b u t e d to the disintegration of these silver cones, it would seem that the p a t t e r n of disintegration would have been the same in all root canals, that is, from the chamber apically. Therefore, because this did not occur a n d no second root canal was found, it was mncluded that no second root canal existed in the mesial root of this tooth. The pattern of disintegration in this case was unusual: one silver cone disintegrated from the apex inward, and another from the c h a m b e r outward; whereas, the third was unaffected. If disintegration of silver runes were to occur in the root canals 0fa tooth, it would seem logical that it would occur from the apex inward and not from the c h a m b e r outward. This disintegration from the apex inward would be expected if it were Presumed that the apical seal was deficient, which was p r o b a b l y the
case in the mesial root canal of this tooth. T h e pulp c h a m b e r of the tooth was sealed from the oral envir o n m e n t with dental cement, which was found to be intact years later. Therefore, it is puzzling that the disintegration began within the c h a m b e r a n d progressed o u t w a r d , leaving a portion of intact silver cone in the apex of one root, unless a c o m m u n i c a t i o n existed from the outside of the tooth into the pulp c h a m ber. If this had been the case, then the question arises as to why the other two silver cones were not similarly affected. Even more puzzling was the presence of an intact portion of silver cone, leading into the mesial canal, directly adjacent to the area of the p u l p c h a m b e r c o n t a i n i n g the coronally disintegrated distal silver cone, However, 1 believe the failure of this case cannot be a t t r i b u t e d to the filling material used, but to other factors. Such a factor could be the probable lack of apical seal in the mesial root canal, allowing the apical portion of this silver cone to corrode and then disintegrate from the apex inward. Also, there might have been a c o m m u n i c a t i o n , via an accessory canal in the furcation of this tooth, between the pulp c h a m b e r a n d the oral e n v i r o n m e n t despite d e n t a l cement filling the pulp c h a m b e r a n d p r e s u m a b l y s u r r o u n d i n g the silver cones. This could explain how corrosion a n d then disintegration of the distal silver cone took place fi'om the c h a m b e r apically. However, the exp l a n a t i o n fails to account for the existence, in proximity, of an unaffected portion of silver cone leading into the mesial root canal a n d an unaffected silver cone in the palatal root canal. T h e above speculations,
and that ing the add
any other points of conjecture the reader m i g h t have, concernthe circumstances a n d cause of e n d o d o n t i c failure of this case to its interest.
SUMMARY A rare instance of disintegration of two silver cones in a maxillary molar made more u n u s u a l because of dissimilar disintegration patterns a n d a n unaffected third silver cone in the same tooth, has been presented. Photographs were taken by the Department of Audio-Visual Services, Emory University School. This case was presented before the annual meeting of the Georgia Associationof Endodontists. Charlotte Amalie, St. Thomas, VI. Oct 8, 1978. The author thanks Dr. Worth Gregory, .Jr., for his help in reviewing the manuscript. Dr. Harris is an endodontist in private practice, tie is also clinical associate, endodontics, Emory University School of l)entistry, Atlanta, and is on the teaching staff in endodontics, Medical College of G-eorgia,School of Dentistry', Augusta. He is chief of cndodnntic sen'ices and director of off-site clinical training, Mas.sell Dental Clinic, Atlanta. Request for reprints should be directed to the author, 401 Peachtree St NE, Atlanta, 30308. References
l. Ingle,J.l., and Beveridge, E.E. Endodontics, ed 2. Philadelphia, I,ea & Febiger, 1976, 255. 2. Luks, S., Gutta-percha versus silver points in the practice ofendodontics. NY Dent J 31:341, 1965. 3. Bender, 1.B. Clinical presentation. Presented at the Southern Endodontic Study Group annual meeting, Williamsburgh, Va, July 1970. 4. Harris, W.E. Disintegration of a silver point: report of case. JADA 83:868, 1971. 5. Acousta Vigouroux, S., and Trugeda Bosaans, S. Anatomy of the pulp chamber of the permanent maxillary,first molar. J Endod 4(7):214, 1978.
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