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Successful management of a perforated mandibular molar using amalgam and hydroxylapatite
0099-2399/87/1308-0400/$02 .(30/0 JOURNALOF ENDODONTICS Copyright 9 1987 by The American Assooation of Endodontists
Printed in U.S.A. VOL. 13, NO. 8, AUGUST 1987
CASE REPORTS Successful Management of a Perforated Mandibular Molar Using Amalgam and Hydroxylapatite James B. Roane, as, DDS, MS, and Fred W. Benenati, DDS, MEd
The case of a mandibular molar with iatrogenic perforations of both roots is presented. Gutta-percha was extruded into the furcation during obturation and subsequently contributed to extensive osseous destruction of that region. The effort to save this seriously involved molar included: a) an internal amalgam repair of the mesial root; (b) a surgical curettage; (c) external amalgam repair of the distal root; and (d) reconstruction of the furcation architecture with a hydroxylapatite graft. A 21-month followup examination verified retention of the graft and tissue reattachment. Results obtained with this tooth offer the possibility of a successful repair technique for this otherwise hopeless complication of endodontic therapy.
(12, 13) show that hydroxylapatite is completely compatible with periodontal tissues. When hydroxylapatite is placed into periodontal defects, it is reported to be a tissue-tolerated foreign body "fill" that is encapsulated by collagen. It does not induce osteogenesis or cementogenesis; however, it elicits no inflammatory or other adverse host response and is not exfoliated. Moskow and Lubarr (13) considered the possibility of periodontally induced furcation defect repair with hydroxylapatite. This case report describes the treatment sequence and follow-up examination of a mandibular molar jeopardized by furcation perforations in both the mesial and distal roots. The perforations were initially closed with gutta-percha but later required internal and external amalgam repairs, furcation curettage, and reconstruction of the furcation architecture with hydroxylapatite.
Perforation into the furcation during endodontic treatment has a notably detrimental effect on prognosis. Several publications (1-5) indicate that furcation perforation predisposes a tooth to periodontal breakdown and a loss of gingival attachment, which in most instances is irreparable and frequently leads to a therapeutic failure. Several clinical studies of furcation perforation consequences have been conducted in which chloroform-softened gutta-percha (6), zinc oxide-eugenol paste (7), Cavit (Premier Dental Products, Norristown, PA) (8), gutta-percha (9, 10), and amalgam (7, 10) were used as the repair material. The published results indicate varying degrees of therapeutic success with each material. Use of the alloplastic material hydroxylapatite in the treatment of periodontal disease has received considerable attention over the past several years (11-15). Studies investigating the effect of reconstructing osseous contours with this material (14, 15) indicate that defect sites measured less pocket depth during followu~ examinations than did sites treated by debridement alone. The evaluation periods of the studies ranged from 1 to 3 yr. Histological studies of human tissues
CASE REPORT
A four-canaled mandibular first molar (Fig. 1) received endodontic treatment in the student clinic at the Uni-
FiG 1. Preoperative film showing extensive loss of coronal structure due to caries. Condensing osteitis is associated with both apices.
40O
Voh 13, No. 8, August 1987
versity of Oklahoma. The patient was a 26-yr-old Caucasian female in good health who had been experiencing pain from chewing and biting on the involved tooth. The pulp was cariously exposed and the periapical bone displayed patterns of condensing osteitis. Treatment progressed uneventfully through two treatment visits; however, upon completion the evaluation radiograph (Fig. 2) indicated, via extruded sealer and gutta-percha, a large lacerated region along the furcation surface of the mesial root. Also noted was a smaller almost inapparent laceration in the middle third of the distal root along its furcation surface. Both perforations were considered to have been a result of overzealous canal preparation with Gates Glidden drills. The patient was informed of these complications; however, she elected to have no intervening treatment at that time. Four months later, the patient returned with soft tissue swelling located facial to the furcation of the described first molar. Periodontal examination indicated extensive loss of gingival attachment along the entire facial aspect with communication into the furcation. The patient desired to save this tooth even though its prognosis was extremely poor. Attempting to fulfill her wishes, an internal amalgam repair procedure, described in a previous paper (10), was accomplished in both mesial canals. A post space was prepared and a Dentatus post (Charles B. Schwed Co., Kew Gardens, NY) was cemented into one of the distal canals. The internal amalgams placed in the mesial perforation sites were secondarily isolated with a wet mix of polycarboxylate cement. The repair process was completed by reconstructing the tooth with silver amalgam. An evaluation radiograph (Fig. 3) indicated that a considerable amount of alloy was forced into the furcation during placement of the internal repairs and that the post preparation had served to enlarge the previous perfo-
FiG 2. Final obturation with extrusion of gutta-percha and sealer into furcation from mesial root perforation.
Management of a Perforated Molar
401
FiG 3. Radiograph of completed post and core. Note extrusion of amalgam into furcation from mesial root as well as cement from perforation of distal root.
ration site in the distal root. As a result, a secondary surgical procedure was suggested and with the patient's consent, treatment was scheduled. Two weeks later, the patient returned for surgical treatment. A local anesthetic of 2% lidocaine and 1:50,000 epinephrine was administered. A sulcular incision was made and a full-thickness mucoperiosteal flap was reflected along the facial aspect. Two verticolateral releasing incisions were made and access was gained to the entire facial osseous area of the involved tooth. Osseous breakdown had destroyed the entire cortical plate facial to the furcation extending from the crest to within approximately 5 mm of the apices (see Fig. 4A). Granulation tissue, amalgam, and cement debris were removed from the furcation area. The lingual cortical bone remained intact and the apical 3 mm of both roots remained encased in sound osseous structure. Radiographs disclosed no apical osseous breakdown; consequently, no periapical treatment was indicated. The perforation site in the distal root was prepared to receive an external amalgam using a #2 round bur in a straight handpiece. As a result of an unusually wide separation between the mesial and distal roots, the concavity and perforation site along the mesial aspect of the distal root could be directly visualized. A class three preparation design was utilized. Retention was gained via shallow vertical grooves cut facial and lingual to the post aided by a rounded penetration into the canal space apical to the post. Amalgam was carried into the prepared space with a Messing gun syringe and condensed into the prepared cavity with a custom-made periapical plugger fabricated from a 33L spoon curette. The completed, but overbulked amalgam was carved to contour with a 33L spoon and a # 5 explorer. The surface and margins were burnished using several # 3 cotton pellets which also aided in the
402
Roane and Benenati
Journal of Endodontic8
One week later sutures were removed. The patient was comfortable and the gingival tissues were healing normally. Probing of the sulcus was not accomplished in order to avoid interference with any potential con. nective tissue reattachment. Follow-up evaluation did not occur until 14 months after the surgical procedure. A bite-wing radiograph (Fig. 6) taken at that time indicated that the graft material was still intact. The patient was asymptomatic and the facial sulcus probed between 2 and 3 mm in depth. The patient again returned for recall at 21 months after surgery. She was still asymptomatic and a periapical radiograph (Fig. 7) indicated continued retention of the graft material plus normal periapical status. Probing depths were no greater than 3 mm and the gingival tissues appeared to be healthy. A cast full crown was subsequently placed (Fig. 8) and the patient was placed on periodic follow-up. DISCUSSION
Perforation of both roots of this molar made the initial prognosis for retention extremely doubtful. Secondary
FiG 4. A, Osseous defect following curettage just prior to placement of hydroxylapatite. B, Surgical procedure included removal of extruded material from the furcation and amalgam repair of the distal root perforation.
removal of loose amalgam particles. The completed repair was examined using a periapical radiograph (Fig. 4B) before further procedures were attempted. Due to the extent of osseous loss, a matrix for support of the soft tissue appeared advisable. Based upon results of several clinical studies (11-15), a mixture of sterile saline and Periograf (Cook-Waite Laboratories, New York, NY) was selected for this purpose. That mixture was packed into the furcal area completely replacing its missing osseous structure from the lingual wall to the facial opening (Fig. 5A). The soft tissues were subsequently closed with 5-0 sutures, the patient was given home care instructions plus an analgesic prescription, and a suture removal appointment was scheduled. A completion radiograph is presented in Fig. 5B.
FIG 5. A, Placement of hydroxylapatite into furcation completed the surgical repair process. B, Completed repair showing radiopaque hydroxylapatite in the furcation.
VOI. 13, No. 8, August 1987
periodontal destruction was predictable (1-5) and without any attempt at repair, the situation was hopeless. Previous experience with amalgam in the repair of root perforations (10) prompted its use in this case. Theoretically, this amalgam repair functions in the same manner as a reverse apical amalgam fill and helps to prevent exchange of fluids between the obturated canals and furcal osseous structure. In this case, extensive loss of furcation bone left no alternative but an attempt to restore the furcation architecture with a graft material. The questionable prognosis was recognized at the time of treatment; however, encouraging results from hydroxylapatite grafts in several studies (11-15) prompted its use in this situation. The clinical and radiographic appearance of this tooth at last examination demonstrates a potential for successful furcation reconstruction using hydroxylapatite at least over a short time span.
FIG 6. A 14-month bite-wing radiograph reveals intact hydroxylapatite in the furcation.
Management of a Perforated Molar
403
FiG 8. The tooth was restored with a full crown. A periodontal probe inserted at the facial aspect of the furcation indicates a depth no greater than 3 mm.
In our opinion, successful repair of perforation defects may be influenced by the following details: (a) repair of the defect with an insoluble material, i.e. amalgam; (b) secondary isolation of the repair using a chelating type base with low solubility such as zinc polycarboxylate; (c) immediate isolation and protection of the soluble base by placement of a coronal amalgam restoration; and (d) completion of this entire process using aseptic techniques as quickly as possible. All steps in the repair process should be considered a part of the canal obturation system. It is speculated that the periodontal response observed in this case related to the patient's physiology as much as to the technique. The treatment utilized allowed the physiological response a more favorable chance to respond because of the following: isolation of the defect from significant salivary microleakage through the perforation sites and support of the soft tissue with a graft to prevent its collapse into the damaged furcation. We wish to acknowledge that this is a single case and the results obtained, while encouraging, are not predictable for all such cases. This report demonstrates the possibility of successful repair where hemisection or extraction have previously been the only routinely used treatment. SUMMARY
FIG 7. Twenty-one-month recall film demonstrates continued retention of hydroxylapatite and no breakdown of apical tissues.
A case has been reported which involved successful repair of perforations in both roots of a mandibular molar. The perforations and filling material extrusion had created gross osseous destruction of the furcation. Internal amalgam placement and a surgical procedure to restore lost furcal periodontal architecture with hydroxylapatite were used. The method presented offers hope for teeth with defects presently considered irreparable.
404
Roane and Benenati
Dr. Roane is associate professor and chairman and Dr. Benenati is assistant professor, Department of Endodontics, University of Oklahoma College of Dentistry, Oklahoma City, OK. Both maintain a Wivate practice, limited to endodontics, in Norman, OK.
References 1. Frank AL. Resorption, perforations and fractures. Dent Clin North Am 1974;18:465-87. 2. Oswald RJ. Procedural accidents and their repair. Dent Clin North Am 1979;23:593-616. 3. Sinai I. Endodontio perforations: their prognosis and treatment. J Am Dent Assoc 1977;95:90-5. 4. Seltzer S, Sinai I, August D. Periodontal effects of root perforations before and during endodontic procedures. J Dent Res 1970;49:332-9. 5. Bhaskar S, Rappaport H. Histotogic evaluation of endodontic procedures in dogs. Oral Surg 1971 ;31:26-35. 6. Stromberg T, Hasselgran G, Bergstedt H. Endodontic treatment of traumatic root perforations in man; a clinical and roentgenological follow-up study. Sven Tandlak Tidskr 1972;65:457-66.
Journal of Endodontics 7. Nioholls E, Treatment of traumatic perforations of the pulp cavity, Oral Surg 1962;15:603-12, 8. Harris W. A simplified method of treatment for endedontic perforations. J Endodon 1976;2:126-33. 9. Meister F, Lommel T, Gerstein, H, et al. Endodontic perforations which resulted in alveolar bone loss. Oral Surg 1979;47:463-70. 10. Benenati F, Roane J, Biggs J, Simon J. Recall evaluation of iatrogenic root perforations repaired with amalgam and gutta-percha. J Endodon 1986;12:161-6. 11. Rabaiais ML, Yukna RA, Mayer ET. Evaluation of Durapatite ceramic as an ailoplastio implant in periodontai osseous defects. I. Initial six-month results. J Periodonto11981 ;52:680-9. 12. Froum SJ, Kushner L, Scopp IW, Stahl SS. Human clinical and histological responses to Durapatite implants in intraosseous lesions. Case reports. J Periodontol 1982;53:719-25. 13. Moskow BS, Lubarr A. Histological assessment of human periodontal defect after Durapatite ceramic implant--report of a case. J Periodontol 1983;54:455-62. 14. Yukna RA, Mayer ET, Bdte DV. Longitudinal evaluation of Durapatite ceramic as an alloplastic implant in pedodontai osseous defects after 3 years. J Periodontol 1984;55:633-7. 15. Yukna RA, Harrison BG, Caudill RF, et al. Evaluation of Durapatite ceramic as an alloplastio implant in periodontal osseous defects. I1. Twelve month reentry results. J Periodonto11985;56:540-7.
Printed in U.S.A. VOL. 13, NO. 8, AUGUST 1987
CASE REPORTS Successful Management of a Perforated Mandibular Molar Using Amalgam and Hydroxylapatite James B. Roane, as, DDS, MS, and Fred W. Benenati, DDS, MEd
The case of a mandibular molar with iatrogenic perforations of both roots is presented. Gutta-percha was extruded into the furcation during obturation and subsequently contributed to extensive osseous destruction of that region. The effort to save this seriously involved molar included: a) an internal amalgam repair of the mesial root; (b) a surgical curettage; (c) external amalgam repair of the distal root; and (d) reconstruction of the furcation architecture with a hydroxylapatite graft. A 21-month followup examination verified retention of the graft and tissue reattachment. Results obtained with this tooth offer the possibility of a successful repair technique for this otherwise hopeless complication of endodontic therapy.
(12, 13) show that hydroxylapatite is completely compatible with periodontal tissues. When hydroxylapatite is placed into periodontal defects, it is reported to be a tissue-tolerated foreign body "fill" that is encapsulated by collagen. It does not induce osteogenesis or cementogenesis; however, it elicits no inflammatory or other adverse host response and is not exfoliated. Moskow and Lubarr (13) considered the possibility of periodontally induced furcation defect repair with hydroxylapatite. This case report describes the treatment sequence and follow-up examination of a mandibular molar jeopardized by furcation perforations in both the mesial and distal roots. The perforations were initially closed with gutta-percha but later required internal and external amalgam repairs, furcation curettage, and reconstruction of the furcation architecture with hydroxylapatite.
Perforation into the furcation during endodontic treatment has a notably detrimental effect on prognosis. Several publications (1-5) indicate that furcation perforation predisposes a tooth to periodontal breakdown and a loss of gingival attachment, which in most instances is irreparable and frequently leads to a therapeutic failure. Several clinical studies of furcation perforation consequences have been conducted in which chloroform-softened gutta-percha (6), zinc oxide-eugenol paste (7), Cavit (Premier Dental Products, Norristown, PA) (8), gutta-percha (9, 10), and amalgam (7, 10) were used as the repair material. The published results indicate varying degrees of therapeutic success with each material. Use of the alloplastic material hydroxylapatite in the treatment of periodontal disease has received considerable attention over the past several years (11-15). Studies investigating the effect of reconstructing osseous contours with this material (14, 15) indicate that defect sites measured less pocket depth during followu~ examinations than did sites treated by debridement alone. The evaluation periods of the studies ranged from 1 to 3 yr. Histological studies of human tissues
CASE REPORT
A four-canaled mandibular first molar (Fig. 1) received endodontic treatment in the student clinic at the Uni-
FiG 1. Preoperative film showing extensive loss of coronal structure due to caries. Condensing osteitis is associated with both apices.
40O
Voh 13, No. 8, August 1987
versity of Oklahoma. The patient was a 26-yr-old Caucasian female in good health who had been experiencing pain from chewing and biting on the involved tooth. The pulp was cariously exposed and the periapical bone displayed patterns of condensing osteitis. Treatment progressed uneventfully through two treatment visits; however, upon completion the evaluation radiograph (Fig. 2) indicated, via extruded sealer and gutta-percha, a large lacerated region along the furcation surface of the mesial root. Also noted was a smaller almost inapparent laceration in the middle third of the distal root along its furcation surface. Both perforations were considered to have been a result of overzealous canal preparation with Gates Glidden drills. The patient was informed of these complications; however, she elected to have no intervening treatment at that time. Four months later, the patient returned with soft tissue swelling located facial to the furcation of the described first molar. Periodontal examination indicated extensive loss of gingival attachment along the entire facial aspect with communication into the furcation. The patient desired to save this tooth even though its prognosis was extremely poor. Attempting to fulfill her wishes, an internal amalgam repair procedure, described in a previous paper (10), was accomplished in both mesial canals. A post space was prepared and a Dentatus post (Charles B. Schwed Co., Kew Gardens, NY) was cemented into one of the distal canals. The internal amalgams placed in the mesial perforation sites were secondarily isolated with a wet mix of polycarboxylate cement. The repair process was completed by reconstructing the tooth with silver amalgam. An evaluation radiograph (Fig. 3) indicated that a considerable amount of alloy was forced into the furcation during placement of the internal repairs and that the post preparation had served to enlarge the previous perfo-
FiG 2. Final obturation with extrusion of gutta-percha and sealer into furcation from mesial root perforation.
Management of a Perforated Molar
401
FiG 3. Radiograph of completed post and core. Note extrusion of amalgam into furcation from mesial root as well as cement from perforation of distal root.
ration site in the distal root. As a result, a secondary surgical procedure was suggested and with the patient's consent, treatment was scheduled. Two weeks later, the patient returned for surgical treatment. A local anesthetic of 2% lidocaine and 1:50,000 epinephrine was administered. A sulcular incision was made and a full-thickness mucoperiosteal flap was reflected along the facial aspect. Two verticolateral releasing incisions were made and access was gained to the entire facial osseous area of the involved tooth. Osseous breakdown had destroyed the entire cortical plate facial to the furcation extending from the crest to within approximately 5 mm of the apices (see Fig. 4A). Granulation tissue, amalgam, and cement debris were removed from the furcation area. The lingual cortical bone remained intact and the apical 3 mm of both roots remained encased in sound osseous structure. Radiographs disclosed no apical osseous breakdown; consequently, no periapical treatment was indicated. The perforation site in the distal root was prepared to receive an external amalgam using a #2 round bur in a straight handpiece. As a result of an unusually wide separation between the mesial and distal roots, the concavity and perforation site along the mesial aspect of the distal root could be directly visualized. A class three preparation design was utilized. Retention was gained via shallow vertical grooves cut facial and lingual to the post aided by a rounded penetration into the canal space apical to the post. Amalgam was carried into the prepared space with a Messing gun syringe and condensed into the prepared cavity with a custom-made periapical plugger fabricated from a 33L spoon curette. The completed, but overbulked amalgam was carved to contour with a 33L spoon and a # 5 explorer. The surface and margins were burnished using several # 3 cotton pellets which also aided in the
402
Roane and Benenati
Journal of Endodontic8
One week later sutures were removed. The patient was comfortable and the gingival tissues were healing normally. Probing of the sulcus was not accomplished in order to avoid interference with any potential con. nective tissue reattachment. Follow-up evaluation did not occur until 14 months after the surgical procedure. A bite-wing radiograph (Fig. 6) taken at that time indicated that the graft material was still intact. The patient was asymptomatic and the facial sulcus probed between 2 and 3 mm in depth. The patient again returned for recall at 21 months after surgery. She was still asymptomatic and a periapical radiograph (Fig. 7) indicated continued retention of the graft material plus normal periapical status. Probing depths were no greater than 3 mm and the gingival tissues appeared to be healthy. A cast full crown was subsequently placed (Fig. 8) and the patient was placed on periodic follow-up. DISCUSSION
Perforation of both roots of this molar made the initial prognosis for retention extremely doubtful. Secondary
FiG 4. A, Osseous defect following curettage just prior to placement of hydroxylapatite. B, Surgical procedure included removal of extruded material from the furcation and amalgam repair of the distal root perforation.
removal of loose amalgam particles. The completed repair was examined using a periapical radiograph (Fig. 4B) before further procedures were attempted. Due to the extent of osseous loss, a matrix for support of the soft tissue appeared advisable. Based upon results of several clinical studies (11-15), a mixture of sterile saline and Periograf (Cook-Waite Laboratories, New York, NY) was selected for this purpose. That mixture was packed into the furcal area completely replacing its missing osseous structure from the lingual wall to the facial opening (Fig. 5A). The soft tissues were subsequently closed with 5-0 sutures, the patient was given home care instructions plus an analgesic prescription, and a suture removal appointment was scheduled. A completion radiograph is presented in Fig. 5B.
FIG 5. A, Placement of hydroxylapatite into furcation completed the surgical repair process. B, Completed repair showing radiopaque hydroxylapatite in the furcation.
VOI. 13, No. 8, August 1987
periodontal destruction was predictable (1-5) and without any attempt at repair, the situation was hopeless. Previous experience with amalgam in the repair of root perforations (10) prompted its use in this case. Theoretically, this amalgam repair functions in the same manner as a reverse apical amalgam fill and helps to prevent exchange of fluids between the obturated canals and furcal osseous structure. In this case, extensive loss of furcation bone left no alternative but an attempt to restore the furcation architecture with a graft material. The questionable prognosis was recognized at the time of treatment; however, encouraging results from hydroxylapatite grafts in several studies (11-15) prompted its use in this situation. The clinical and radiographic appearance of this tooth at last examination demonstrates a potential for successful furcation reconstruction using hydroxylapatite at least over a short time span.
FIG 6. A 14-month bite-wing radiograph reveals intact hydroxylapatite in the furcation.
Management of a Perforated Molar
403
FiG 8. The tooth was restored with a full crown. A periodontal probe inserted at the facial aspect of the furcation indicates a depth no greater than 3 mm.
In our opinion, successful repair of perforation defects may be influenced by the following details: (a) repair of the defect with an insoluble material, i.e. amalgam; (b) secondary isolation of the repair using a chelating type base with low solubility such as zinc polycarboxylate; (c) immediate isolation and protection of the soluble base by placement of a coronal amalgam restoration; and (d) completion of this entire process using aseptic techniques as quickly as possible. All steps in the repair process should be considered a part of the canal obturation system. It is speculated that the periodontal response observed in this case related to the patient's physiology as much as to the technique. The treatment utilized allowed the physiological response a more favorable chance to respond because of the following: isolation of the defect from significant salivary microleakage through the perforation sites and support of the soft tissue with a graft to prevent its collapse into the damaged furcation. We wish to acknowledge that this is a single case and the results obtained, while encouraging, are not predictable for all such cases. This report demonstrates the possibility of successful repair where hemisection or extraction have previously been the only routinely used treatment. SUMMARY
FIG 7. Twenty-one-month recall film demonstrates continued retention of hydroxylapatite and no breakdown of apical tissues.
A case has been reported which involved successful repair of perforations in both roots of a mandibular molar. The perforations and filling material extrusion had created gross osseous destruction of the furcation. Internal amalgam placement and a surgical procedure to restore lost furcal periodontal architecture with hydroxylapatite were used. The method presented offers hope for teeth with defects presently considered irreparable.
404
Roane and Benenati
Dr. Roane is associate professor and chairman and Dr. Benenati is assistant professor, Department of Endodontics, University of Oklahoma College of Dentistry, Oklahoma City, OK. Both maintain a Wivate practice, limited to endodontics, in Norman, OK.
References 1. Frank AL. Resorption, perforations and fractures. Dent Clin North Am 1974;18:465-87. 2. Oswald RJ. Procedural accidents and their repair. Dent Clin North Am 1979;23:593-616. 3. Sinai I. Endodontio perforations: their prognosis and treatment. J Am Dent Assoc 1977;95:90-5. 4. Seltzer S, Sinai I, August D. Periodontal effects of root perforations before and during endodontic procedures. J Dent Res 1970;49:332-9. 5. Bhaskar S, Rappaport H. Histotogic evaluation of endodontic procedures in dogs. Oral Surg 1971 ;31:26-35. 6. Stromberg T, Hasselgran G, Bergstedt H. Endodontic treatment of traumatic root perforations in man; a clinical and roentgenological follow-up study. Sven Tandlak Tidskr 1972;65:457-66.
Journal of Endodontics 7. Nioholls E, Treatment of traumatic perforations of the pulp cavity, Oral Surg 1962;15:603-12, 8. Harris W. A simplified method of treatment for endedontic perforations. J Endodon 1976;2:126-33. 9. Meister F, Lommel T, Gerstein, H, et al. Endodontic perforations which resulted in alveolar bone loss. Oral Surg 1979;47:463-70. 10. Benenati F, Roane J, Biggs J, Simon J. Recall evaluation of iatrogenic root perforations repaired with amalgam and gutta-percha. J Endodon 1986;12:161-6. 11. Rabaiais ML, Yukna RA, Mayer ET. Evaluation of Durapatite ceramic as an ailoplastio implant in periodontai osseous defects. I. Initial six-month results. J Periodonto11981 ;52:680-9. 12. Froum SJ, Kushner L, Scopp IW, Stahl SS. Human clinical and histological responses to Durapatite implants in intraosseous lesions. Case reports. J Periodontol 1982;53:719-25. 13. Moskow BS, Lubarr A. Histological assessment of human periodontal defect after Durapatite ceramic implant--report of a case. J Periodontol 1983;54:455-62. 14. Yukna RA, Mayer ET, Bdte DV. Longitudinal evaluation of Durapatite ceramic as an alloplastic implant in pedodontai osseous defects after 3 years. J Periodontol 1984;55:633-7. 15. Yukna RA, Harrison BG, Caudill RF, et al. Evaluation of Durapatite ceramic as an alloplastio implant in periodontal osseous defects. I1. Twelve month reentry results. J Periodonto11985;56:540-7.