1. Friedman S. Treatment outcome and prognosis of endodontic therapy. In: Ørstavik D, Pitt F0rd T, ed: Essential endodontology: Prevention and treatment of apical periodontitis. 2nd ed. Blackwell Munksgaard; 2008.

2. Strindberg LZ. The dependence of the results of pulp therapy on certain factors: an analytic study based on radiographic and clinical follow-up examinations: Acta Odontol Scand 1956; 14: suppl 21

3. Farzaneh M, Abitbol S, Lawrence HP, Friedman S. Treatment outcome in endodontics-The Toronto study. Phase II: Initial treatment. J Endod 2004; 30: 302-309.

4. Weiger R, Rosendahl R, Löst C. Influence of calcium hydroxide intracanal dressings on the prognosis of teeth with endodontically induced periapical lesions. Int Endod J 2000; 33: 219-226.

5. Friedman S, Abitbol S, Lawrence HP. Treatment outcome in endodontics: The Toronto study. Phase 1: Initial treatment. J Endod 2003; 29: 787-793.

6. Peters L, Wesselink P. Periapical healing of endodontically treated teeth in one and two visits obturated in the presence or absence of detectable microorganisms. Int Endod J 2002; 35: 660-667.

7. Sjögren U, Hägglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod 1990; 16: 498-504.

8. Sjögren U, Figdor D, Persson S, Sundqvist G. Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 1997; 30: 297-306.

9. Friedman S, Löst C, Zarrabian M, Trope M. Evaluation of success and failure after endodontic therapy using a glass ionomer cement sealer. J Endod 1995; 21: 384-390.

10. Ricucci D, Lin LM, Spångberg LSW. Wound healing of apical tissues after root canal therapy: a long-term clinical, radiographic, and histopathologic observation study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 609-621.

11. Garlet GP, Horwat R, Ray Jr HL, Garlet TP, Silveira EM, Campanelli AP, et al. Expression analysis of wound healing genes in human periapical granulomas of progressive and stable nature. J Endod 2012; 38: 185-190.

12. Nair PNR. On the causes of persistent apical periodontitis: a review. Int Endod J 2006; 39: 249-281.

13. Barbat J, Messer HH. Detectability of artificial periapical lesions using direct digital and conventional radiography. J Endod 1998; 24: 837-842.

14. Lee SJ, Messer HH. Radiographic appearance of artificially prepared periapical lesions confined to cancellous bone. Int Endod J 1986; 19: 64-72.

15. Bender IB, Seltzer S. Roentgenographic and direct observation of experimental lesions in bone: I. J Endod 2003; 29: 702-706.

16. Bender IB, Seltzer S. Roentgenographic and direct observation of experimental lesions in bone: II. J Endod 2003; 29: 707-712.

17. Friedman S. Prognosis of initial endodontic therapy. Endod Topics 2002; 2: 59-88.

18. Moller AJR, Fabricius L, Dahlen G, Ohman AE, Heyden GUY. Influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys. Eur J Oral Sci 1981; 89: 475-484.

19. Kakehashi S, Stanley HR, Fitzgerald RJ. The effects of surgical exposures of dental pulps in germ-free and conventional laboratory rats. Oral Surg Oral Med Oral Pathol 1965; 20: 340-349.

20. Byström A, Claesson R, Sundqvist G. The antibacterial effect of camphorated paramonochlorophenol, camphorated phenol and calcium hydroxide in the treatment of infected root canals. Dent Traumatol 1985; 1: 170-175.

21. Byström A, Sundqvist G. Bacteriologic evaluation of the effect of 0.5 percent sodium hypochlorite in endodontic therapy. Oral Surg Oral Med Oral Pathol 1983; 55: 307-312.

22. Byström A, Happonen R-P, Sjögren U, Sundqvist G. Healing of periapical lesions of pulpless teeth after endodontic treatment with controlled asepsis. Dent Traumatol 1987; 3: 58-63.

23. Ørstavik D, Kerekes K, Molven O. Effects of extensive apical reaming and calcium hydroxide dressing on bacterial infection during treatment of apical periodontitis: a pilot study. Int Endod J 1991; 24: 1-7.

24. Molander A, Reit C, Dahlén G, Kvist T. Microbiological status of root-filled teeth with apical periodontitis. Int Endod J 1998; 31: 1-7.

25. Sathorn C, Parashos P, Messer HH. How useful Is root canal culturing in predicting treatment outcome? J Endod 2007; 33: 220-225.

26. Anderson AC, Hellwig E, Vespermann R, Wittmer A, Schmid M, Karygianni L, et al. Comprehensive analysis of secondary dental root canal infections: A combination of culture and culture-independent approaches reveals new insights. PloS one (e49576. doi:10.1371/journal.pone.0049576). 2012 Nov; 7(11). Available from: http://www.plosone.org/article/info%3Adoi%2F10.137...

27. Rôças IN, Jung I-Y, Lee C-Y, Siqueira Jr JF. Polymerase chain reaction identification of microorganisms in previously root-filled teeth in a south Korean population. J Endod 2004; 30: 504-508.

28. Torabinejad M, Eby WC, Naidorf IJ. Inflammatory and immunological aspects of the pathogenesis of human periapical lesions. J Endod 1985; 11: 479-488.

29. Hundagoon S, Pattamapun K, Khemaleelakul S. : Level of matrix metalloproteinase-2 and matrix metalloproteinase-8 in root canal exudate during root canal treatment. Paper read at 1st Asean Plus Three Graduate Research Congress. 1-2 March 2012, at Chiang Mai Thailand

30. Takayama S, Miki Y, Shimauchi H, Okada H. Relationship between prostaglandin E2 concentrations in periapical exudates from root canals and clinical findings of periapical periodontitis. J Endod 1996; 22: 677-680.

31. Alptekin NO, Ari H, Haliloglu S, Alptekin T, Serpek B, Ataoglu T. The effect of endodontic therapy on periapical exudate neutrophil elastase and prostaglandin-E2 levels. J Endod 2005; 31: 791-795.

32. Ataglu T, Üngör M, Serpek B, Haliloglu S, Ataoglu H, Ari H. Interleukin-1β and tumour necrosis factor-α levels in periapical exudates. Int Endod J 2002; 35: 181-185.

33. Bender IB, Seltzer S, Soltanoff W. Endodontic success - A reappraisal of criteria: Part II. Oral Surg Oral Med Oral Pathol 1966; 22: 790-802.

34. Endodontology ESo. Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. Int Endod J 2006; 39: 921-930.

35. Bender IB, Seltzer S, Soltanoff W. Endodontic success - A reappraisal of criteria: Part I. Oral Surg Oral Med Oral Pathol 1966; 22: 780-789.

36. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature – Part 1. Effects of study characteristics on probability of success. Int Endod J 2007; 40: 921-939.

37. Molven O, Halse A, Fristad I, MacDonald-Jankowski D. Periapical changes following root-canal treatment observed 20-27 years postoperatively. Int Endod J 2002; 35: 784-790.

38. Ørstavik D. Time-course and risk analyses of the development and healing of chronic apical periodontitis in man. Int Endod J 1996; 29 : 150-155.

39. Huumonen S, Ørstavik D. Radiological aspects of apical periodontitis. Endod Topics 2002; 1: 3-25.

40. Gröndahl H-G, Gröndahl K, Webber RL. A digital subtraction technique for dental radiography. Oral Surg Oral Med Oral Pathol 1983; 55: 96- 102.

41. Mikrogeorgis G, Lyroudia K, Molyvdas I, Nikolaidis N, Pitas I. Digital radiograph registration and subtraction: a useful tool for the evaluation of the progress of chronic apical periodontitis. J Endod 2004; 30: 513-517.

42. Benfica e Silva J, Leles CR, Alencar AHG, Nunes CABCM, Mendonça EF. Digital subtraction radiography evaluation of the bone repair process of chronic apical periodontitis after root canal treatment. Int Endod J 2010;

43: 673-680. 43. Karayianni K, Bragger U, Burgin W, Nielsen PM, P. LN. Diagnosis of alveolar bone changes with digital subtraction images and conventional radiographs: An in vitro study. Oral Surg Oral Med Oral Pathol 1991; 72: 251-256.

44. Patel S, Dawood A, Ford TP, Whaites E. The potential applications of cone beam computed tomography in the management of endodontic problems. Int Endod J 2007; 40: 818-830.

45. Patel S, Wilson R, Dawood A, Mannocci F. The detection of periapical pathosis using periapical radiography and cone beam computed tomography - Part 1: pre-operative status. Int Endod J 2012; 45: 702.

46. American Association of Endodontist. Chicago: Endodontica Colleagues for Excellence Cone Beam-Computed Tomography in Endodontics; c 2011. Available from: http://www.aae.org/ uploadedfiles/publications_and_research/endodontics_colleagues_for_excellence_newsletter/ ecfe%20summer%2011%20final.pdf.

47. Patel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography. Int Endod J 2009; 42: 507-515.

48. Paula-Silva FWG, Wu MK, Leonardo MR, Bezerra da Silva LA, Wesselink PR. Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard. J Endod 2009; 35: 1009-1012.

49. Patel S, Wilson R, Dawood A, Foschi F, Mannocci F. The detection of periapical pathosis using digital periapical radiography and cone beam computed tomography - Part 2: a 1-year post-treatment follow-up. Int Endod J 2012; 45: 711-723.

50. Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of Cone Beam Computed Tomography and panoramic and periapical radiography for detection of apical periodontitis. J Endod 2008; 34: 273-279.

51. Katsumata A, Hirukawa A, Noujeim M, Okumura S, Naitoh M, Fujishita M, et al. Image artifact in dental cone-beam CT. Oral Surg Oral Med Oral Pathol Oral Rad Endod 2006; 101: 652-657.

52. Ørstavik D, Kerekes K, Eriksen HM. The periapical index: A scoring system for radiographic assessment of apical periodontitis. Dent Traumatol 1986; 2: 20-34.

53. Brynolf L. Histological and roentgenological study of the periapical region of human upper incisors. Odontal Revy 1967; 18(Suppl.11): 1-176.

54. Tanomaru-Filho M, Jorge EG, Duarte MAH, Gonçalves M, Guerreiro-Tanomaru JM. Comparative radiographic and histological analyses of periapical lesion development. Oral Surg Oral Med Oral Pathol Oral Rad Endod 2009; 107: 442-447.