Dental Traumatology 2015; 31: 437–441; doi: 10.1111/edt.12199
Pulp canal obliteration after replantation of avulsed immature teeth: a systematic review Ashraf Abd-Elmeguid, Mohamed ElSalhy, Donald C. Yu School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
Key words: avulsion; immature apex; calcific metamorphosis; pulp canal obliteration; pulp calcification; replantation Correspondence to: Ashraf Abd-Elmeguid, Endodontic Division, School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, 5-546 Edmonton Clinic Health Academy, Edmonton, AB T6G 1C9, Canada Tel.: +1 780 492 1344 e-mail: [email protected] Accepted 30 May 2015
Abstract – Background: Avulsion of permanent teeth is one of the most serious dento-alveolar traumatic injuries. Pulp canal obliteration (PCO) is one of the consequences after replantation of avulsed immature teeth. The aim of this systematic review was to determine when calcification following replantation of an avulsed immature tooth begins and to evaluate the prevalence of PCO in these cases. Materials and methods: Electronic database MEDLINE via Ovid, PubMed, Cochrane, and Web of science databases were searched. Hand searching was performed through reference lists of endodontic and trauma textbooks, endodontic and trauma-related journals, and relevant articles from electronic searching. Pooled data from the selected articles were analyzed for prevalence of healing and PCO as well as mean first evidence of PCO. Results: Pulp healing after replantation of immature teeth occurred in 32.9%, while pulpal necrosis occurred in 67.1% of teeth. PCO was the most frequent outcome of pulpal healing as it occurred in 96% of healed pulps. First evidence of obliteration was observed from 3 to 14 months with mean time of 9.5 months (95% CI = 4.5–14.5 months). Conclusions: PCO is considered the mechanism by which the pulp heals after replantation of avulsed immature permanent teeth. PCO is very fast and can be recognized radiographically during the first year from the onset of the trauma.
The classification of dento-alveolar traumatic injuries was developed by the World Health Organization (WHO) in 1969 (1) and modified by Andreasen and Andreasen et al., in 1972 (2). Up to 33% of children in their first and second decades of life are prone to dento-alveolar traumatic injuries (3, 4). Avulsion and intrusion of permanent teeth are considered the most serious dento-alveolar traumatic injuries (5). Avulsed teeth may possibly survive following their replantation. However, successful replantation requires successful management of both damaged periodontal and pulpal tissues (6–8). Despite the treatment provided, 21–89% of replanted teeth are eventually lost and have the poorest outcomes of all dento-alveolar traumas (8–13). Factors that affect the success of the replantation procedure include the type of storage medium, extra-alveolar time, the degree of damage to the periodontium, the condition of the pulp, and the degree of root development (5). Possible complications are pulpal necrosis, inflammation and infection related root resorption, root ankylosis, and tooth loss (14). Pulpal management in avulsed teeth is different from other forms of trauma due to complete loss of blood supply. After replantation, root canal treatment should be initiated 7–10 days for closed-apex teeth (6). In case of immature teeth with open apices, there is a possibility for pulp revascularization (14–16) with subsequent formation of © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
intrapulpal hard tissue known as pulp canal obliteration (PCO), also referred to as calcific metamorphosis. PCO can be either partial or complete (7). Although considered a sign of healing (7, 8, 17, 18), both partial and complete PCO represent a problem in negotiating the pulp canal if the need for endodontic treatment arises due to subsequent pulpal necrosis or other reasons (19). However, the risk of secondary pulp necrosis, even in the case of restorations, prosthetics, or orthodontic treatments, is limited (20). The yellowish discoloration of the crown (6, 13, 18) and the lack of pulpal sensibility (16, 18) are also considered as other clinical complications. The aim of this systematic review was to determine when calcification following replantation of an avulsed immature tooth begins and to evaluate the prevalence of PCO in replanted immature avulsed teeth. This will provide clinicians with the evidence needed for the follow up of such cases. Materials and methods Literature search
Electronic search of MEDLINE (Ovid), PubMed, Cochrane library, and Web of science databases was performed (Table 1). PubMed and Web of science 437
438
Abd-Elmeguid et al.
Table 1. Search strategy through MEDLINE via Ovid’s website and PubMed, cochrane library, and web of science databases (January 1950–April 2014) Search terms
Results
Replant* Pulp healing Avuls* Immature root Dental trauma Calcific* 1 AND 2 3 AND 4 5 AND 6 9 OR 10 OR 11 12 limit human 13 limit English
7931 1357 9433 1215 18 049 50 118 100 86 226 394 292 257
*either the verb or the noun.
found nearly all the selected abstracts by databases. A manual search was also conducted. The author’s name which was repeated several times was also searched. Finally, a reference list of relevant articles from both the electronic and manual searches was screened again. Eight textbooks including Principles and Practice of Endodontics (Torabinejad and Walton, 4th edn, 2008), Pathways of the Pulp (Cohen and Hargreaves, 9th edn, 2006), Endodontics (Ingle, Bakland, and Baumgartner, 6th edn, 2008), Textbook of Endodontology (Bergenholtz, Horsted-Bindslev, and Reit, 2nd edn, 2010), Endodontics (Stock, Walter, and Gulabivala, 3rd edn, 2004), Essential Endodontology (Ostarvik and Pitt Ford, 2nd edn, 2008), Seltzer and Bender’s Dental Pulp (Hargreaves and Goodis, 3rd edn, 2002), and Textbook and color atlas of traumatic injuries to the teeth (Andreasen, Andreasen, and Andersson, 4th edn, 2007) and 5 trauma and endodontic-related journals (International Endodontic Journal, Journal of Endodontics, Oral Surgery Oral Medicine Oral Pathology Oral Radiology Endodontology, Dental Traumatology, and Australian Endodontic Journal) were hand searched. Inclusion criteria
1 Original studies on human patients that dealt with the replantation of avulsed immature teeth. 2 Pulpal healing in the studies was in the form of revascularization or pulpal obliteration whether partial or complete. 3 At least 1-year follow-up period. 4 Articles written in English. Exclusion criteria
1 All case reports and articles that dealt with root resorption after replantation; 2 Studies of the avulsion of deciduous teeth and; 3 Studies that did not fulfill the validity criteria. Study selection and assessment of validity
The titles and abstracts of all identified articles were screened by two independent reviewers to eliminate
articles that did not meet inclusion criteria. Full text articles were analyzed when the abstract was not enough to include or exclude the studies. The studies that did not meet the inclusion criteria were excluded. Articles which met the inclusion criteria were assessed for validity. Validity was determined based on the evaluation of two independent reviewers. When there was any doubt, the paper was reread and validity determined. Validity of the selected papers was determined by the presence of the following two criteria: 1 Number of teeth that have shown pulp canal obliteration mentioned. 2 Evaluation period at which obliteration was observed mentioned. Results
Electronic search identified 257 studies as shown in Table 1. After screening by two reviewers, 52 abstracts were selected using the initial inclusion criteria and selection process. Finally, seven papers were selected (8, 9, 11, 13–15, 21). Two of the selected papers used the same sample. Therefore, only one set of data was used in our results. PRISMA flow diagram of systematic searching process is shown in Fig. 1. The total number of replanted immature teeth, the number of healed pulps, the number of healed pulps that underwent PCO, the number of necrotic teeth, the time at which PCO was first observed, and the follow-up period were extracted from the selected studies (Table 2). The total number of teeth included in this analysis was 228. The follow-up period for these teeth was in the range of 3 months to 13 years with a minimum of 1-year evaluation for every patient. Time of publication was between 1966 and 2005. The age of patients was between 6–9 years. Pulp healing after replantation of immature teeth occurred in 75 teeth (32.9%), while pulpal necrosis occurred in 153 teeth (67.1%). PCO was the most frequent outcome of pulpal healing as it occurred in 96% of healed pulps. First evidence of obliteration was observed from 3 to 14 months with mean time of 9.5 months (95% CI = 4.5–14.5 months). Discussion
Several factors are involved in the process of pulp healing with pulp canal obliteration. These factors are extra-oral time, storage conditions, apex width, root canal length, and frequency of traumatic episodes on the tooth (5, 22). The International Association of Dental Trauma (IADT) guidelines in 2012 stated that the extra-oral time is the most important factor in determining pulp healing and root canal treatment could be avoided in immature teeth unless there is clinical and radiographic evidence of pulp necrosis (6). Our results showed that pulp necrosis occurs in twothirds of replanted avulsed immature teeth, while only one-third undergo healing. PCO is the most common healing outcome of the pulp after avulsion as it accounts for 96% of all healed teeth. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Identification
Pulp canal obliteration after replantation
Records identified through database searching (n = 257)
439
Additional records identified through other sources (n = 19)
Screening
Records after duplicates removed (n = 257)
Records screened (n = 257)
Records excluded (n = 205)
Eligibility
• Full-text articles assessed for eligibility (n = 52)
Included
•
45 studies Excluded because the evaluation period at which obliteration was observed was not mentioned One study of two papers used the same sample
Studies included in qualitative synthesis (n = 6)
Fig. 1. PRISMA flow diagram of systematic searching process.
Teeth with PCO provide an endodontic treatment challenge if these teeth require endodontic intervention. This is in line with the American Association of Endodontists Case Assessment criteria (23) which categorized PCO teeth as a high difficulty category. Furthermore, this condition cannot be prevented and at the same time, endodontic intervention is not indicated as long as clinical signs of necrosis are absent. As to pulp healing in the form of obliteration after avulsion and replantation of immature teeth, the data showed that pulp canal obliteration began from as early as the 3 months with a mean of 9.5 months following replantation which highlights the importance of close monitoring of the case during the first year. All the selected articles did not use controls to compare the narrowing of the pulp spaces, with the exception of Andreasen et al. (9, 14) who used weekly
radiographs as controls for the first month. Also, they used the neighboring teeth as controls in case of multiple avulsed teeth in the same patient to compare revascularization. However, the IADT recommendations for clinical and radiographic follow-up controls are at 4 weeks, 3 months, 6 months, 1 year, and then yearly thereafter (6). Generally, the retention rate of teeth after endodontic treatment is high. An initial endodontic treatment analyses carried out in 1.5 million teeth and with a follow up of over 8 years, found an overall retention rate of 97.1% (24). In addition, the success rate of endodontic treatment of obliterated root canals was 62.5%, when periapical radiolucencies were present prior to the treatment and 97.9% for roots without periapical radiolucencies after 2- to 12-year follow up (17). About 7–27% of teeth with PCO will develop
Table 2. Data extracted from seven articles reported PCO after replantation of avulsed immature teeth
Author (year)
Number of immature teeth
Andreasen & Hjorting-Hansen (1966) (9) Kling et al. (1986) (15) Gonda et al. (1990) (11) Andreasen et al. (1995 a,b) (7, 8) Ebeleseder et al. (1998) (13) Chappuis & von Arx (2005) (21) Totals
13 72 4 94 39 6 228
Follow-up period 3 month–13 years At least 18 month At least 15 month 4 month–1.5 years 2.5 1.38 years 1 year
1
Seven with bone formation. Three with bone formation.
2
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Number of pulpal healing teeth
Number of teeth healed with pulpal obliteration
Number of teeth undergo pulpal necrosis
Time at which PCO first observed
7 13 4 32 16 3 75
7 131 4 292 16 3 72
6 59 0 62 23 3 153
12 months 3 months 12 months 4 months 14 months 12 months Mean = 9.5
440
Abd-Elmeguid et al.
pulp necrosis with radiographic signs of periapical disease (25). Moreover, the frequency of pulpal necrosis may increase over time (26). The inevitable lack of responses to normal sensibility tests and crown discoloration adds uncertainty to the management (14, 18– 20, 25). All these reasons support initiation of root canal treatment. On the other hand, avulsed immature teeth generally have short roots and thin walls which compromise the strength of the tooth and increase risk of root fracture (27). Also, open apices teeth may lack apical seal and have risk of extrusion of the root canal material out of the apex (5). The use of magnification can improve the outcome of the endodontic treatment (28). This may enhance endodontic therapy for the treatment of a tooth with PCO. Furthermore, Robertson et al. (20) reported that caries, restorative, or orthodontic treatments do not increase the risk of pulp necrosis in addition to low necrosis rate in PCO cases. Successful management of avulsed teeth requires both successful endodontic and periodontal healing. About 30% of necrotic avulsed teeth are at risk of infection-related root resorption (9, 14, 29) which makes the management more complicated and success less predictable. As two-thirds of replanted immature teeth undergo necrosis, initiation of pulp revascularization/regeneration early after replantation is a suggested treatment approach. This approach would promote root maturation/completion as well as avoid necrosisassociated complications. Further studies are needed to evaluate this treatment suggestion. Extra-oral time is considered the main contributing factor for both pulpal and periodontal healing. Andreasen and Hjorting-Hansen (9) and Andreasen et al. (14) indicated the extra-oral dry storage time, while the others only stated that post-traumatic storage was ideal. In the first study, 12 of 13 teeth were less than 45 min in dry conditions and healing was observed in seven teeth. In the second study, the healing rate of teeth stored dry for less than 5 min was 50%, while those stored for more than 20 min was only 28%. Kling et al., (15) and Andreasen et al. (14) observed that there was a bony in-growth from the alveolar bone inside the pulp, identified by the presence of lamina dura (Table 2). Huang et al. (30) suggested this to be attributed to cells of the dental papilla, while Zhao et al. (31) reported that these bone-forming cells originated mainly from the pulp in rats. PCO hard tissue in replanted immature teeth is composed of two types of tissue, reparative dentin and bone (32). Different experimental studies suggest the possibility of the presence of osteogenic promoter cells that tend to differentiate into osteoblast-like cells and form bone-like tissue inside the pulp (31, 32). This may explain the rapid occurrence of pulp space obliteration in replanted immature teeth. Conclusion
In conclusion, PCO is considered the mechanism by which the pulp heals after replantation of avulsed immature permanent teeth. PCO is very fast and can
be recognized radiographically during the first year from the onset of the trauma. Acknowledgements
There is no conflict of interest by any of the authors. References 1. World Health Organization. Application of the international classification of diseases to dentistry and stomatology: ICDDA, 3rd edn. Geneva: World Health Organization; 1995. 2. Andreasen JO, Andreasen FM. Textbook and color atlas of traumatic injuries to the teeth, 3rd edn. Copenhagen: Munksgaard; 1993. 3. Oginni AO, Adekoya-Sofowora CA. Pulpal sequelae after trauma to anterior teeth among adult Nigerian dental patients. BMC Oral Health 2007;7:11. 4. Jarvinen S. Fractured and avulsed permanent incisors in Finnish children. A retrospective study. Acta Odontol Scand 1979;37:47–50. 5. Andreasen JO, Andreasen FM, Andersson L. Textbook and color atlas of traumatic injuries to the teeth, 4th edn. Oxford, UK; Ames, Iowa: Blackwell Munksgaard; 2007. 6. Andersson L, Andreasen JO, Day P, Heithersay G, Trope M, Diangelis AJ et al. International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 2. Avulsion of permanent teeth. Dent Traumatol 2012;28:88–96. 7. Andreasen JO, Borum MK, Jacobsen HL, Andreasen FM. Replantation of 400 avulsed permanent incisors. 2. Factors related to pulpal healing. Endod Dent Traumatol 1995;11: 59–68. 8. Andreasen JO, Borum MK, Jacobsen HL, Andreasen FM. Replantation of 400 avulsed permanent incisors. 4. Factors related to periodontal ligament healing. Endod Dent Traumatol 1995;11:76–89. 9. Andreasen JO, Hjorting-Hansen E. Replantation of teeth. I. Radiographic and clinical study of 110 human teeth replanted after accidental loss. Acta Odontol Scand 1966;24:263–86. 10. Kemp WB, Grossman LI, Phillips J. Evaluation of 71 replanted teeth. J Endod 1977;3:30–5. 11. Gonda F, Nagase M, Chen RB, Yakata H, Nakajima T. Replantation: an analysis of 29 teeth. Oral Surg Oral Med Oral Pathol 1990;70:650–5. 12. Mackie IC, Worthington HV. An investigation of replantation of traumatically avulsed permanent incisor teeth. Br Dent J 1992;172:17–20. 13. Ebeleseder KA, Friehs S, Ruda C, Pertl C, Glockner K, Hulla H. A study of replanted permanent teeth in different age groups. Endod Dent Traumatol 1998;14:274–8. 14. Andreasen JO, Borum MK, Jacobsen HL, Andreasen FM. Replantation of 400 avulsed permanent incisors. 1. Diagnosis of healing complications. Endod Dent Traumatol 1995;11: 51–8. 15. Kling M, Cvek M, Mejare I. Rate and predictability of pulp revascularization in therapeutically reimplanted permanent incisors. Endod Dent Traumatol 1986;2:83–9. 16. Amir FA, Gutmann JL, Witherspoon DE. Calcific metamorphosis: a challenge in endodontic diagnosis and treatment. Quintessence Int 2001;32:447–55. 17. Akerblom A, Hasselgren G. The prognosis for endodontic treatment of obliterated root canals. J Endod 1988;14:565–7. 18. Soares Ade J, Gomes BP, Zaia AA, Ferraz CC, de Souza-Filho FJ. Relationship between clinical-radiographic evaluation and outcome of teeth replantation. Dent Traumatol 2008; 24:183–8. 19. Oginni AO, Adekoya-Sofowora CA, Kolawole KA. Evaluation of radiographs, clinical signs and symptoms associated
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Pulp canal obliteration after replantation
20.
21.
22.
23. 24.
25.
26.
with pulp canal obliteration: an aid to treatment decision. Dent Traumatol 2009;25:620–5. Robertson A, Andreasen FM, Bergenholtz G, Andreasen JO, Noren JG. Incidence of pulp necrosis subsequent to pulp canal obliteration from trauma of permanent incisors. J Endod 1996;22:557–60. Chappuis V, von Arx T. Replantation of 45 avulsed permanent teeth: a 1-year follow-up study. Dent Traumatol 2005;21:289–96. Day P, Duggal M. Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted. Cochrane Database Syst Rev 2010;20;(1):CD006542. American Association of Endodontics. Case Difficulty Assessment Form and Guidelines B 2006 (Edited 2010). Salehrabi R, Rotstein I. Endodontic treatment outcomes in a large patient population in the USA: an epidemiological study. J Endod 2004;30:846–50. McCabe PS, Dummer PM. Pulp canal obliteration: an endodontic diagnosis and treatment challenge. Int Endod J 2012;45:177–97. Andreasen FM, Zhijie Y, Thomsen BL, Andersen PK. Occurrence of pulp canal obliteration after luxation injuries in the permanent dentition. Endod Dent Traumatol 1987; 3:103–15.
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27. Andreasen JO, Farik B, Munksgaard EC. Long-term calcium hydroxide as a root canal dressing may increase risk of root fracture. Dent Traumatol 2002;18:134–7. 28. Bowers DJ, Glickman GN, Solomon ES, He J. Magnification’s effect on endodontic fine motor skills. J Endod 2010;36:1135–8. 29. Boyd DH, Kinirons MJ, Gregg TA. A prospective study of factors affecting survival of replanted permanent incisors in children. Int J Paediatr Dent 2000;10:200–5. 30. Huang GT, Sonoyama W, Liu Y, Liu H, Wang S, Shi S. The hidden treasure in apical papilla: the potential role in pulp/ dentin regeneration and bioroot engineering. J Endod 2008;34:645–51. 31. Zhao C, Hosoya A, Kurita H, Hu T, Hiraga T, Ninomiya T et al. Immunohistochemical study of hard tissue formation in the rat pulp cavity after tooth replantation. Arch Oral Biol 2007;52:945–53. 32. Tsukamoto-Tanaka H, Ikegame M, Takagi R, Harada H, Ohshima H. Histochemical and immunocytochemical study of hard tissue formation in dental pulp during the healing process in rat molars after tooth replantation. Cell Tissue Res 2006;325:219–29.
Pulp canal obliteration after replantation of avulsed immature teeth: a systematic review Ashraf Abd-Elmeguid, Mohamed ElSalhy, Donald C. Yu School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
Key words: avulsion; immature apex; calcific metamorphosis; pulp canal obliteration; pulp calcification; replantation Correspondence to: Ashraf Abd-Elmeguid, Endodontic Division, School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, 5-546 Edmonton Clinic Health Academy, Edmonton, AB T6G 1C9, Canada Tel.: +1 780 492 1344 e-mail: [email protected] Accepted 30 May 2015
Abstract – Background: Avulsion of permanent teeth is one of the most serious dento-alveolar traumatic injuries. Pulp canal obliteration (PCO) is one of the consequences after replantation of avulsed immature teeth. The aim of this systematic review was to determine when calcification following replantation of an avulsed immature tooth begins and to evaluate the prevalence of PCO in these cases. Materials and methods: Electronic database MEDLINE via Ovid, PubMed, Cochrane, and Web of science databases were searched. Hand searching was performed through reference lists of endodontic and trauma textbooks, endodontic and trauma-related journals, and relevant articles from electronic searching. Pooled data from the selected articles were analyzed for prevalence of healing and PCO as well as mean first evidence of PCO. Results: Pulp healing after replantation of immature teeth occurred in 32.9%, while pulpal necrosis occurred in 67.1% of teeth. PCO was the most frequent outcome of pulpal healing as it occurred in 96% of healed pulps. First evidence of obliteration was observed from 3 to 14 months with mean time of 9.5 months (95% CI = 4.5–14.5 months). Conclusions: PCO is considered the mechanism by which the pulp heals after replantation of avulsed immature permanent teeth. PCO is very fast and can be recognized radiographically during the first year from the onset of the trauma.
The classification of dento-alveolar traumatic injuries was developed by the World Health Organization (WHO) in 1969 (1) and modified by Andreasen and Andreasen et al., in 1972 (2). Up to 33% of children in their first and second decades of life are prone to dento-alveolar traumatic injuries (3, 4). Avulsion and intrusion of permanent teeth are considered the most serious dento-alveolar traumatic injuries (5). Avulsed teeth may possibly survive following their replantation. However, successful replantation requires successful management of both damaged periodontal and pulpal tissues (6–8). Despite the treatment provided, 21–89% of replanted teeth are eventually lost and have the poorest outcomes of all dento-alveolar traumas (8–13). Factors that affect the success of the replantation procedure include the type of storage medium, extra-alveolar time, the degree of damage to the periodontium, the condition of the pulp, and the degree of root development (5). Possible complications are pulpal necrosis, inflammation and infection related root resorption, root ankylosis, and tooth loss (14). Pulpal management in avulsed teeth is different from other forms of trauma due to complete loss of blood supply. After replantation, root canal treatment should be initiated 7–10 days for closed-apex teeth (6). In case of immature teeth with open apices, there is a possibility for pulp revascularization (14–16) with subsequent formation of © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
intrapulpal hard tissue known as pulp canal obliteration (PCO), also referred to as calcific metamorphosis. PCO can be either partial or complete (7). Although considered a sign of healing (7, 8, 17, 18), both partial and complete PCO represent a problem in negotiating the pulp canal if the need for endodontic treatment arises due to subsequent pulpal necrosis or other reasons (19). However, the risk of secondary pulp necrosis, even in the case of restorations, prosthetics, or orthodontic treatments, is limited (20). The yellowish discoloration of the crown (6, 13, 18) and the lack of pulpal sensibility (16, 18) are also considered as other clinical complications. The aim of this systematic review was to determine when calcification following replantation of an avulsed immature tooth begins and to evaluate the prevalence of PCO in replanted immature avulsed teeth. This will provide clinicians with the evidence needed for the follow up of such cases. Materials and methods Literature search
Electronic search of MEDLINE (Ovid), PubMed, Cochrane library, and Web of science databases was performed (Table 1). PubMed and Web of science 437
438
Abd-Elmeguid et al.
Table 1. Search strategy through MEDLINE via Ovid’s website and PubMed, cochrane library, and web of science databases (January 1950–April 2014) Search terms
Results
Replant* Pulp healing Avuls* Immature root Dental trauma Calcific* 1 AND 2 3 AND 4 5 AND 6 9 OR 10 OR 11 12 limit human 13 limit English
7931 1357 9433 1215 18 049 50 118 100 86 226 394 292 257
*either the verb or the noun.
found nearly all the selected abstracts by databases. A manual search was also conducted. The author’s name which was repeated several times was also searched. Finally, a reference list of relevant articles from both the electronic and manual searches was screened again. Eight textbooks including Principles and Practice of Endodontics (Torabinejad and Walton, 4th edn, 2008), Pathways of the Pulp (Cohen and Hargreaves, 9th edn, 2006), Endodontics (Ingle, Bakland, and Baumgartner, 6th edn, 2008), Textbook of Endodontology (Bergenholtz, Horsted-Bindslev, and Reit, 2nd edn, 2010), Endodontics (Stock, Walter, and Gulabivala, 3rd edn, 2004), Essential Endodontology (Ostarvik and Pitt Ford, 2nd edn, 2008), Seltzer and Bender’s Dental Pulp (Hargreaves and Goodis, 3rd edn, 2002), and Textbook and color atlas of traumatic injuries to the teeth (Andreasen, Andreasen, and Andersson, 4th edn, 2007) and 5 trauma and endodontic-related journals (International Endodontic Journal, Journal of Endodontics, Oral Surgery Oral Medicine Oral Pathology Oral Radiology Endodontology, Dental Traumatology, and Australian Endodontic Journal) were hand searched. Inclusion criteria
1 Original studies on human patients that dealt with the replantation of avulsed immature teeth. 2 Pulpal healing in the studies was in the form of revascularization or pulpal obliteration whether partial or complete. 3 At least 1-year follow-up period. 4 Articles written in English. Exclusion criteria
1 All case reports and articles that dealt with root resorption after replantation; 2 Studies of the avulsion of deciduous teeth and; 3 Studies that did not fulfill the validity criteria. Study selection and assessment of validity
The titles and abstracts of all identified articles were screened by two independent reviewers to eliminate
articles that did not meet inclusion criteria. Full text articles were analyzed when the abstract was not enough to include or exclude the studies. The studies that did not meet the inclusion criteria were excluded. Articles which met the inclusion criteria were assessed for validity. Validity was determined based on the evaluation of two independent reviewers. When there was any doubt, the paper was reread and validity determined. Validity of the selected papers was determined by the presence of the following two criteria: 1 Number of teeth that have shown pulp canal obliteration mentioned. 2 Evaluation period at which obliteration was observed mentioned. Results
Electronic search identified 257 studies as shown in Table 1. After screening by two reviewers, 52 abstracts were selected using the initial inclusion criteria and selection process. Finally, seven papers were selected (8, 9, 11, 13–15, 21). Two of the selected papers used the same sample. Therefore, only one set of data was used in our results. PRISMA flow diagram of systematic searching process is shown in Fig. 1. The total number of replanted immature teeth, the number of healed pulps, the number of healed pulps that underwent PCO, the number of necrotic teeth, the time at which PCO was first observed, and the follow-up period were extracted from the selected studies (Table 2). The total number of teeth included in this analysis was 228. The follow-up period for these teeth was in the range of 3 months to 13 years with a minimum of 1-year evaluation for every patient. Time of publication was between 1966 and 2005. The age of patients was between 6–9 years. Pulp healing after replantation of immature teeth occurred in 75 teeth (32.9%), while pulpal necrosis occurred in 153 teeth (67.1%). PCO was the most frequent outcome of pulpal healing as it occurred in 96% of healed pulps. First evidence of obliteration was observed from 3 to 14 months with mean time of 9.5 months (95% CI = 4.5–14.5 months). Discussion
Several factors are involved in the process of pulp healing with pulp canal obliteration. These factors are extra-oral time, storage conditions, apex width, root canal length, and frequency of traumatic episodes on the tooth (5, 22). The International Association of Dental Trauma (IADT) guidelines in 2012 stated that the extra-oral time is the most important factor in determining pulp healing and root canal treatment could be avoided in immature teeth unless there is clinical and radiographic evidence of pulp necrosis (6). Our results showed that pulp necrosis occurs in twothirds of replanted avulsed immature teeth, while only one-third undergo healing. PCO is the most common healing outcome of the pulp after avulsion as it accounts for 96% of all healed teeth. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Identification
Pulp canal obliteration after replantation
Records identified through database searching (n = 257)
439
Additional records identified through other sources (n = 19)
Screening
Records after duplicates removed (n = 257)
Records screened (n = 257)
Records excluded (n = 205)
Eligibility
• Full-text articles assessed for eligibility (n = 52)
Included
•
45 studies Excluded because the evaluation period at which obliteration was observed was not mentioned One study of two papers used the same sample
Studies included in qualitative synthesis (n = 6)
Fig. 1. PRISMA flow diagram of systematic searching process.
Teeth with PCO provide an endodontic treatment challenge if these teeth require endodontic intervention. This is in line with the American Association of Endodontists Case Assessment criteria (23) which categorized PCO teeth as a high difficulty category. Furthermore, this condition cannot be prevented and at the same time, endodontic intervention is not indicated as long as clinical signs of necrosis are absent. As to pulp healing in the form of obliteration after avulsion and replantation of immature teeth, the data showed that pulp canal obliteration began from as early as the 3 months with a mean of 9.5 months following replantation which highlights the importance of close monitoring of the case during the first year. All the selected articles did not use controls to compare the narrowing of the pulp spaces, with the exception of Andreasen et al. (9, 14) who used weekly
radiographs as controls for the first month. Also, they used the neighboring teeth as controls in case of multiple avulsed teeth in the same patient to compare revascularization. However, the IADT recommendations for clinical and radiographic follow-up controls are at 4 weeks, 3 months, 6 months, 1 year, and then yearly thereafter (6). Generally, the retention rate of teeth after endodontic treatment is high. An initial endodontic treatment analyses carried out in 1.5 million teeth and with a follow up of over 8 years, found an overall retention rate of 97.1% (24). In addition, the success rate of endodontic treatment of obliterated root canals was 62.5%, when periapical radiolucencies were present prior to the treatment and 97.9% for roots without periapical radiolucencies after 2- to 12-year follow up (17). About 7–27% of teeth with PCO will develop
Table 2. Data extracted from seven articles reported PCO after replantation of avulsed immature teeth
Author (year)
Number of immature teeth
Andreasen & Hjorting-Hansen (1966) (9) Kling et al. (1986) (15) Gonda et al. (1990) (11) Andreasen et al. (1995 a,b) (7, 8) Ebeleseder et al. (1998) (13) Chappuis & von Arx (2005) (21) Totals
13 72 4 94 39 6 228
Follow-up period 3 month–13 years At least 18 month At least 15 month 4 month–1.5 years 2.5 1.38 years 1 year
1
Seven with bone formation. Three with bone formation.
2
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Number of pulpal healing teeth
Number of teeth healed with pulpal obliteration
Number of teeth undergo pulpal necrosis
Time at which PCO first observed
7 13 4 32 16 3 75
7 131 4 292 16 3 72
6 59 0 62 23 3 153
12 months 3 months 12 months 4 months 14 months 12 months Mean = 9.5
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pulp necrosis with radiographic signs of periapical disease (25). Moreover, the frequency of pulpal necrosis may increase over time (26). The inevitable lack of responses to normal sensibility tests and crown discoloration adds uncertainty to the management (14, 18– 20, 25). All these reasons support initiation of root canal treatment. On the other hand, avulsed immature teeth generally have short roots and thin walls which compromise the strength of the tooth and increase risk of root fracture (27). Also, open apices teeth may lack apical seal and have risk of extrusion of the root canal material out of the apex (5). The use of magnification can improve the outcome of the endodontic treatment (28). This may enhance endodontic therapy for the treatment of a tooth with PCO. Furthermore, Robertson et al. (20) reported that caries, restorative, or orthodontic treatments do not increase the risk of pulp necrosis in addition to low necrosis rate in PCO cases. Successful management of avulsed teeth requires both successful endodontic and periodontal healing. About 30% of necrotic avulsed teeth are at risk of infection-related root resorption (9, 14, 29) which makes the management more complicated and success less predictable. As two-thirds of replanted immature teeth undergo necrosis, initiation of pulp revascularization/regeneration early after replantation is a suggested treatment approach. This approach would promote root maturation/completion as well as avoid necrosisassociated complications. Further studies are needed to evaluate this treatment suggestion. Extra-oral time is considered the main contributing factor for both pulpal and periodontal healing. Andreasen and Hjorting-Hansen (9) and Andreasen et al. (14) indicated the extra-oral dry storage time, while the others only stated that post-traumatic storage was ideal. In the first study, 12 of 13 teeth were less than 45 min in dry conditions and healing was observed in seven teeth. In the second study, the healing rate of teeth stored dry for less than 5 min was 50%, while those stored for more than 20 min was only 28%. Kling et al., (15) and Andreasen et al. (14) observed that there was a bony in-growth from the alveolar bone inside the pulp, identified by the presence of lamina dura (Table 2). Huang et al. (30) suggested this to be attributed to cells of the dental papilla, while Zhao et al. (31) reported that these bone-forming cells originated mainly from the pulp in rats. PCO hard tissue in replanted immature teeth is composed of two types of tissue, reparative dentin and bone (32). Different experimental studies suggest the possibility of the presence of osteogenic promoter cells that tend to differentiate into osteoblast-like cells and form bone-like tissue inside the pulp (31, 32). This may explain the rapid occurrence of pulp space obliteration in replanted immature teeth. Conclusion
In conclusion, PCO is considered the mechanism by which the pulp heals after replantation of avulsed immature permanent teeth. PCO is very fast and can
be recognized radiographically during the first year from the onset of the trauma. Acknowledgements
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