Apexification and apexogenesis

Apexification and apexogenesis

1. APEXIFICATION AND APEXOGENESIS 1 7/21/2017 9:32 AM

2. Definition – open apex Absence of sufficient root development to provide a conical taper to the canal and is also referred to as blunderbuss canal. ( Franklein S. Weine 1972 ) Due to trauma or carious exposure, the pulp undergoes necrosis, dentin formation ceases and root growth is arrested. The resultant immature root will have an apical opening that is very large. This is called an open apex, also referred to previously as a blunderbuss canal. . (Thomas R.Pittford,1989) 2 7/21/2017 9:32 AM

3. Causes of open apices caries with pulp involvement, extensive resorption of the mature apex as a result of orthodontic treatment, Periapical pathosis , Trauma causing necrosis This open apex causes two major problems. The normal crown /root ratio is compromised and may cause mobility. It becomes difficult to achieve an apical seal with conventional root canal filling. 3 7/21/2017 9:32 AM

4. Types of open apices These can be of two configurations: 1- non-blunderbuss 2- blunderbuss 4 7/21/2017 9:32 AM

5. Non –blunderbuss: The apex - broad (cylinder shaped) tapered (convergent) 5 Blunderbuss: The apex is funnel shaped and -typically wider than the coronal aspect of the canal. 7/21/2017 9:32 AM

6. Hertwig Sensitive to trauma – increase vascularity and cellularity Important role of Hertwig’s epithelial root sheath in continued root development after pulpal injury, every effort should be made to Maintain its viability. Unfortunately traumatic injuries to young permanent teeth are not uncommon and are said to affect 30% of children . The majority of these incidents occur before root formation is complete and may result in pulpal inflammation or necrosis. 6 Pulp injury in teeth with developing roots 7/21/2017 9:32 AM

7. Complete destruction of Hertwig’s epithelial root sheath results in cessation of normal root development Hard tissue can be formed by : Cementoblasts - apical region F ibroblasts of the dental follicle P eriodontal ligament that undergo differentiation after the injury to become hard tissue producing cells . 7 7/21/2017 9:32 AM

8. Stages of root development Cvek 1972 8 In anatomy the  apical foramen  is the opening at the apex of the  root  of a  tooth , through which the  nerve  and  blood vessels  that supply the  dental pulp  pass. Thus it represents the junction of the pulp & the   periodontal  tissue 7/21/2017 9:32 AM

9. Problems associated with immature apex Large open apices Thin dentinal walls Frequent periapical lesions Short roots Fracture of crown Discoloration on long standing 9 7/21/2017 9:32 AM

10. Diagnosis and case assessment Clinical assessment of pulp status, clinical & radiographic examination. Subjective symptoms Pain history – s pontaneous, severe, long lasting Throbbing, tender to touch - pulpal necrosis with apical periodontitis or acute abscess Swelling /sinus tract - indicates pulpal necrosis and acute or chronic abscess respectively Tenderness to percussion - inflammation in the periapical tissues . 10 7/21/2017 9:32 AM

11. Vitality testing Prior to root formation , the sensory plexus of nerves in the sub odontoblastic region is not well developed. Radiographic interpretation 11 Diagnosis and case assessment 7/21/2017 9:32 AM

12. Treatment Treatment is based on the vitality of the pulp . If the immature tooth has vital pulp, exhibiting reversible pulpitis, then physiological root end development or apexogenesis is attempted . On the other hand if irreversible pulpitis is present or pulp is necrotic, then root end closure or apexification is induced. 12 7/21/2017 9:32 AM

13. 13 Reversible pulpitis Open apex Closed apex Irreversible pulpitis / necrotic pulp Vital pulp therapy Root canal therapy Root end closure Pulp regeneration 7/21/2017 9:32 AM

14. Apexogenesis / vital pulp therapy The current terminology is vital pulp therapy ( Walton and Torabinejad ) “ Apexogenesis is defined as treatment of a vital pulp in an immature tooth to permit continued root growth and apical closure. A vital pulp of an immature tooth may have a small exposure after trauma.” - Ingle “Physiologic root end development and formation” according to American Association of Endodontists in 1981 . 14 7/21/2017 9:32 AM

15. Definition Apexogenesis as endodontic treatment of partially developed permanent teeth that clinically and radiographically displays evidence of pulp necrosis. Stephen Wei (1988) Treatment of vital pulp in an immature tooth to permit continued root growth & apical closure. ( Thomas R. Pitt Ford, 1989) The procedure encourages normal root & apex formation of pulpally involved, vital permanent teeth with immature root development . (AAPD Guidelines 1998) The continued formation of the root in the teeth with vital root pulpal tissue .(McDonald & Aver, 2000) 15 7/21/2017 9:32 AM

16. INDICATIONS Immature tooth with incomplete root formation and damage to the coronal pulp but with a presumed healthy radicular pulp. Lack of abscess formation, excessive haemorrhage, no foul odour Normal radiographic appearance Absence of sensitivity to percussion No abnormal responses to thermal stimuli 16 7/21/2017 9:32 AM

17. CONTRAINDICATIONS Avulsed and replanted or severely luxated tooth Severe crown root fracture that requires intraradicular retention for restoration Tooth with an unfavorable horizontal root fracture (i.e. close to the gingival margin) Carious tooth that is unrestorable 17 7/21/2017 9:32 AM

18. Goals of Apexogenesis : ( Weber 1984) Sustaining a viable Hertwigs Sheath, thus allowing continued development of root length for a more favorable crown to root ratio . Maintaining pulpal vitality, thus allowing the remaining odontoblasts to lay down dentin, producing a thicker root and decreasing the chance of root fracture . Promoting root end closure, thus allowing a natural apical constriction for root canal filling . Generating a dentinal bridge at the site of pulpotomy 18 7/21/2017 9:32 AM

19. PROCEDURE Anesthetize and isolate . After local anesthesia , rubber dam isolation, a conventional access cavity was made with a high-speed bur using copious water spray. Strands of pulp and debris were removed coronal to the amputation site. Amputation of the coronal pulp at the cervical level was performed with a sharp spoon excavator or a large sterile round bur. 19 7/21/2017 9:32 AM

20. PROCEDURE Bleeding of the pulp stump was controlled with saline on a cotton pellet applied with gentle pressure. [Ca(OH) 2 ]: Calcium hydroxide powder was mixed with saline to a thick consistency. The paste was carefully placed on the pulp stump surface 1 to 2 mm thick. 20 Removal of coronal pulp Haemostasis 7/21/2017 9:32 AM

21. Calcium hydroxide placement 21 7/21/2017 9:32 AM

22. Follow-up Time required 1 and 2 years depending on the degree of tooth development at the time of the procedure . Recalled every 3 months Clinically , the treatment was considered successful if there were no signs or symptoms of pulp or periapical disease (no history of pain and no clinical evidence of swelling or sinus tract ). Radiographically , the treatment was considered successful if there was continued growth of the root and canal narrowing, and no widened periodontal ligament , no periapical radiolucency and no internal or external root resorption . 22 7/21/2017 9:32 AM

23. CONTROVERSY EXISTS As the entire coronal pulp was removed, thermal and electrical testing of the tooth is no longer possible. Since it is not possible to determine the pulp vitality or the health of the remaining pulp tissue, it has been advocated that the tooth should be re-entered and root canal therapy performed . 23 7/21/2017 9:32 AM

24. Mejare & Cvek (1993) 37 young posterior teeth - deep carious lesions and exposed pulps Group 1 - 31 teeth with no clinical or radiographic symptoms before treatment. Group 2 - 6 teeth with temporary pain, widened periodontal space periapically After an observation time of 24 to140 months , healing had occurred in 29 of 31 teeth in Group 1 (93.5%) and in 4 of 6 teeth in Group 2. It was concluded that partial pulpotomy may be an adequate treatment for young permanent molars with a carious exposure 24 7/21/2017 9:32 AM

25. Mahmood K et al.,(2006) 32 first permanant molars of 23 patients with age of 10 yrs Clinically and radiographically within the normal limits Partial pulpotomy with grey MTA was done GIC base was given and amalgam/ SS crown restoration was done Reviewed clinically and radiographically at 3,6,12 & 24 months 22 teeth – No clinical and radiographic signs 6 teeth - not responded to vitality tests 25 7/21/2017 9:32 AM

26. Kessar et al.,(2006) A paradigm shift from apexification to apexogenesis Apexogenesis can be done even in a non vital teeth No instrumantation should be done Copious irrigation with 20 ml of NaOCl , dry with paper points and IRM restoration Apexogenesis occurred over a period of 35 month 26 7/21/2017 9:32 AM

27. Ali Nosrat et al., (2006) 8 yr old boy with complicated crown fracture w rt 21 Cervical pulpotomy done with CEM ( Calcium enriched mixture ) After 6 and 12 months follow up tooth is vital , apex has formed and calcific bridge underneath the cement was found . CEM is a new endodontic cement with similar applications as MTA Antimicrobial nature comparable to CH and MTA Composition of set CEM is similar to dentin 27 7/21/2017 9:32 AM

28. Apexification Defined as the method of inducing apical closure by the formation of osteo cementum or a similar hard tissue or the continued apical development of the root of an incompletely formed tooth in which the pulp is no longer vital. – American Association of Endodontics 28 7/21/2017 9:32 AM

29. Definition A method of inducing apical closure of the roots of an incompletely formed, nonvital radicular tissue just short of root end and placing a suitable biocompatible agent in the canal. (AAPD Guidelines 1998) The process of creating an environment within the root canal and periapical tissues after pulp death that allows a calcified barrier to form across the open apex. (Thomas R. Pitt Ford, 1989) Inducement to form a calcified apical barrier in teeth that have pulpal necrosis. (McDonald & Avery, 2000) 29 7/21/2017 9:32 AM

30. ‘ Root-End Closure’ , introduced by Torabinejad in 2002 . 30 Indication – restorable immature tooth with pulp necrosis. Contraindications All vertical and unfavorable horizontal root fractures. Very short roots Periodontal breakdown 7/21/2017 9:32 AM

31. Objectives Induce root end closure No evidence of post treatment signs and symptoms No evidence of calcification No internal or external resorption No breakdown of periradicular supporting tissues 31 7/21/2017 9:34 AM

32. According to Morse et al., (1983) various approaches : Blunt end or rolled cone (customized cone) Short fill technique Periapical surgery (with /without retrograde seal) Apexification (apical closure induction) 32 7/21/2017 9:34 AM

33. Blunt end or rolled cone (customized cone) 33 Filling the root canal with the large end of gutta percha cone is customized cone is not advisable because the apical foramen is generally wider than the root canal orifice. This would prevent proper condensation of the gutta percha and proper preparation of the canal would weaken the tooth considerably It would also be difficult to assess the point of root development radiographically because root formation in the buccolingual plane is less advanced than it is in the mesiodistal plane. 7/21/2017 9:32 AM

34. Short fill Moodnick proposed removal of the bulk of the necrotic tissue & filling the root canal short of the apex with gutta percha He advocated use of Diaket ( premier dental products). It is a compound of beta ketones & zinc oxide in place of gutta percha to enhance healing. However with an incomplete obturation , microbes can be left remaining within the apical part of the root canal system & healing may not take place or periapical breakdown may occur later. 34 7/21/2017 9:32 AM

35. Periapical surgery The gutta percha / sealer surgical approach has many drawbacks. Many clinicians do not advocate this method of treatment for one or more of the following reasons: Relative to the already shortened roots, further reduction could result in an inadequate crown to root ratio. Surgery could be both physically & psychologically traumatic to the young patient. The young patient is non cooperative Surgery would remove the root sheath & prevent the possibility of further root development 35 7/21/2017 9:32 AM

36. The apical walls are thin & could shatter when touched by a rotating bur The periapical tissue may not adapt to the wide & irregular surface of the amalgam The thin walls would make condensation of a retrograde material difficult. This can result in an inadequate seal. 36 7/21/2017 9:32 AM

37. Apical closure induction Most widely used approach but exact mechanism unknown It has been considered that treatment of teeth with necrotic pulp the basic aim should be stimulation & preservation of the formative activity of the granulation tissue cells in apical part of the root canal This should enhance the formation of a calcified callus in the wide apical opening. 37 7/21/2017 9:32 AM

38. One visit apexification Induction of apical healing, regardless of the material used, takes at least 3–4 months and requires multiple appointments Patient compliance with this regimen may be poor and many fail to return for scheduled visits The temporary seal may fail resulting in re-infection and prolongation or failure of treatment For these reasons one-visit apexification has been suggested Morse et al., (1990) define one-visit apexification as the non-surgical condensation of a biocompatible material into the apical end of the root canal 38 7/21/2017 9:32 AM

39. One visit Apexification The rationale is to establish an apical stop that would enable the root canal to be filled immediately There is no attempt at root end closure. Rather an artificial apical stop is created 39 7/21/2017 9:32 AM

40. Materials to induce Apexification in teeth with immature apices Calcium hydroxide Ca(OH) 2 for apexification in the pulpless tooth was first reported by Kaiser in 1964 The technique was popularised by the work of Frank in 1966 40 7/21/2017 9:32 AM

41. Other medicaments Tricalcium phosphate Collagen calcium phosphate. Resorbable Tricalcium phosphate. Mineral trioxide aggregate. Biodentine Bone morphogenic proteins 41 7/21/2017 9:32 AM

42. Time required for apical barrier formation in apexification using calcium hydroxide 42 Study Findings Sheehy and Roberts 1997 an average length of time for apical barrier formation ranging from 5 to 20 months Finucane and Kinirons 1991 calcium hydroxide apexification and found that the mean time to barrier formation was 34.2 weeks (range 13–67 weeks) Cvek 1972 infection and/or the presence of a periapical radiolucency at the start of treatment increases the time required for barrier formation Kleier and Barr 2013 presence of symptoms the time required for apical closure was extended by approximately 5 months to an average of 15.9 months. 7/21/2017 9:32 AM

43. Procedure Anesthetize and isolate Access is made Instrumentation Initial treatment length Acc to Torneck et al & Holland et al., Primary aim- Enlargement Acc to Ingel – H files, circumferential filling 43 7/21/2017 9:32 AM

44. If periapical abscess is present, over-instrumentation with smaller files (20-25) will establish drainage. Ingle recommends that further treatment should be done only when active lesion has subsided. Irrigation Sodium hypochlorite Alternation with hydrogen peroxide - weine Subsequent appointments-sterile water or isotonic saline - Webber 44 7/21/2017 9:32 AM

45. Drying of the canals Often difficult because of seepage Paper points are pre measured to working length An inverted coarse point is often desirable. In continuous seepage, a pre fitted point can be left in canal until calcium hydroxide is placed 45 7/21/2017 9:32 AM

46. Techniques of calcium hydroxide placement: Commercial preparations Webbers technique Using amalgam carrier and endodontic pluggers . 3-4 increments of CH is placed with amalgam carries and pushed apicaly with a plugger . 46 7/21/2017 9:32 AM

47. Successive increments is placed with amalgam carrier and pushed apicaly with larger plugger . Care should be taken to see that material is in contact with periapical tissue. 47 7/21/2017 9:32 AM

48. Temporary restoration ZOE /IRM Material is vertically condensed to make 4-5 mm of space in access. Break of occlusal seal leads to, contamination and dilution of paste, also exposure of healing tissues to microorganisms. 48 7/21/2017 9:32 AM

49. Refilling procedure- Holland F irst recall is at 6 weeks Paste is diluted in canal . Acc to Holland et al., R emoved 1-2mm short of the original working length Remaining powder on canal walls removed with larger size instruments. 49 7/21/2017 9:32 AM

50. Recall Recalled 6 wks after second replacement, later 2-3 months there after until calcific barrier is formed radiographically . Total time 12 – 18 months. Subsequent replacement depends upon radiographic examination. If any symptoms develop refilling is necessary. 50 7/21/2017 9:32 AM

51. Procedure to detect barrier formation Radiographic evaluation Paper point 51 7/21/2017 9:32 AM

52. Mechanism of action of Ca(OH) 2 to induce formation of a solid apical barrier Presence of high Ca concentrations increases the activity of calcium dependent pyrophosphate Direct effect on the apical and periapical soft tissue High pH will activate alkaline phosphatase Antibacterial activity 52 7/21/2017 9:32 AM

53. According to Cruz et al.1998., histological analysis of the apical barrier O uter surface of the bridge extended in a ‘cap like ’. The histological sections showed distinct layers . Dense acellular cementum -like tissue. Irregular dense fibrocollagenous connective tissue with irregular fragments of highly mineralized calcifications. 53 7/21/2017 9:32 AM

54. Nature and source of cells participating in Apexification process Mesenchymal / pluripotent cells in the periapical region Cells of dental sac Odontogenic activity of residual pulp cells Connective tissue cells- mesenchymal /fibroblastic cells Pluripotent cells –bone tissue 54 7/21/2017 9:32 AM

55. Structure of apical barrier Conflicting views Solid structure- cementoid tissue In a clinical case by H.S Chawla & Krishna et al., it was seen that the following apical closure , the sealer used with the gutta percha for obturation had extruded beyond the bridge. The authors concluded that if the calcified bridge would have been a solid structure, the sealer could not have gone in the periapex . So the bridge formed is a porous structure. 55 7/21/2017 9:32 AM

56. Five outcomes of apexification procedure ( weine ): No radiographic change is apparent; but if instrument is inserted, a blockage at the apex is encountered. Radiographic evidence of calcified material is seen at or near the apex. Apex closes without any change in canal space. Apex continues to develop with closure of the canal apace. No radiographic evidence of change is seen, and clinical symptom and/or development of or the increase in size of periapical lesion occurs. This would need either re-treatment with CaOH 2 or surgery. 56 7/21/2017 9:32 AM

57. Inherent disadvantages of calcium hydroxide apexification Variability of treatment time Unpredictability of apical closure Difficulty to patient follow up Delayed treatment 57 7/21/2017 9:32 AM

58. 58 Study No. of treated teeth CaOH used Time for ABF range/mean Success Rates Heithersday , 1970 21 CaOH & methyl cellulose 14-75 mo 90% Cvek, 1972 55 CaOH powder & saline 18.2 mo 90% Winter, 1977 34 Reogan-Rapid—27 teeth CaOH powder & sterile water-27 teeth Not stated 74% Chawla et al., 1986 26 Reogan -Rapid 35% in 12 mo, 65% in 6 mo. 100% Ghose et al., 1987 51 Calasept 3-10 mo 96% Studies where CaOH was used to induce apical barrier formation (ABF) and healing. 7/21/2017 9:32 AM

59. 59 Study Number of treated teeth CaOH used Time for ABF range/mean Success Rates Thater et al., 1988 34 Pulpdent Not stated 74% Mackie et al., 1988 112 Reogan -Rapid 10.3mo 96% Yates, 1988 22 teeth-study grp 22 teeth-control grp CaOH powder & sterile water or Hypocal 9 mo study grp 20.2 mo control group 100% Kleier et al., 1991 48 CaOH paste & Pulpdent 1.6y, 1-30 mo. 100% Mackie et al., 1994 19 19 Reogan -Rapid Hypocal 6.8 mo 5.1mo 100% 100% Studies where CaOH was used to induce apical barrier formation (ABF) and healing. 7/21/2017 9:32 AM

60. MTA ( Mineral trioxide aggregate) Mineral trioxide aggregate (MTA) was first developed by Torabinejad and members at the Loma Linda University, California, USA Initially it was used as a root-end filling material in endodontic treatment It is a mixture of dicalcium silicate, tricalcium silicate, tricalcium aluminate , gypsum, tetracalcium aluminoferrite and bismuth oxide The addition of bismuth powder makes it radio opaque Original grey and a newer white 60 7/21/2017 9:32 AM

61. COMPOSITION OF GREY NAD WHITE MTA 7/21/2017 9:32 AM 61

62. Physical and chemical properties 1. Ph MTA has a pH similar to that of calcium hydroxide of 12.5 This similarity with calcium hydroxide is thought to contribute to its inductive potential and the resultant hard tissue formation The pH of MTA as it set was measured with a pH meter using a temperature-compensated electrode. 62 7/21/2017 9:32 AM

63. 2. Sealing ability & marginal adaptation The quality of apical seal for different retrograde materials has been assessed by different research groups, based on the degree of penetration by dye radio-isotope bacterial electro-chemical means and fluid filtration techniques 63 7/21/2017 9:32 AM

64. 2. Sealing ability & marginal adaptation MTA is also associated with less overfills and the superior outcome associated with the material is observed with or without blood contamination of the root cavities In a study carried out by Fischer et al.1998, using bacterial leakage model, the time period in which materials began leaking was 10-63 days for amalgam, 24- 91 days for IRM. MTA did not begin to leak till day 49. The superior sealing ability of MTA is thought to be due to the setting expansion it undergoes in moist environment 64 7/21/2017 9:32 AM

65. COMPRESSIVE STRENGTH MTA has a relatively low compressive strength; however, this does not compromise its success as it is used in situations that experience low compressive forces. Sluyk et al..(1998) studied setting properties of MTA and found that MTA reached its maximum resistance level if left undisturbed for 72 hours before placement of a permanent restoration 65 7/21/2017 9:32 AM

66. BIOCOMPATIBILTY Material analysis of MTA shows the material to be divided into calcium oxide and calcium phosphate. The scanning electron microscopic studies revealed that amorphous calcium phosphate showed maximum ingress and growth of cells. They concluded that MTA offers a biological substrate for osteoblasts and the calcium phosphate phase favoured the change in cell behavior that stimulated growth over MTA 66 7/21/2017 9:32 AM

67. INDUCTIVE POTENTIAL Torabinejad et al. and colleagues 1995 used infected premolars in two-year old beagle dogs, which were prepared to receive gutta-percha root-fillings The root fillings were left to contaminate by means of open access cavities and subsequently underwent root resection and retrograde fillings with either MTA or amalgam Although periosteum and new bone formation were found in the presence of both materials, histologic findings at 10-18 weeks post-surgery confirmed the formation of cementum exclusively over the root ends with MTA, which included the MTA itself. 67 7/21/2017 9:32 AM

68. INDUCTIVE POTENTIAL Shabahang et al. 1997 carried out apexification in immature dog-teeth using Calcium hydroxide osteogenic protein and MTA. MTA induced hard tissue formation more than any other test material at 12 weeks, resulting in root-end closure 68 7/21/2017 9:32 AM

69. Cytotoxicity An in vitro study conducted by Osorio et al. in 1998 compared different root canal sealers and root end filling materials using two assay systems and two different mammalian fibroblast cell line . Their conclusions were based on the fact that if a material exhibits a strong cytotoxicity in cell culture tests, it is very likely to do so in living tissue. Of the materials tested, MTA was the least cytotoxic . 69 7/21/2017 9:32 AM

70. Sridhar et al.,(2010) The aim of the case reports was to present a treatment to promote root-end growth and apexification in nonvital immature permanent teeth in children. Three cases were presented where the calcium hydroxide and iodoform paste Metapex ® was placed in the root canals of immature permanent teeth using disposable plastic tips. The teeth involved were evaluated radiographically at regular intervals for the first 12 months after placement of the paste. At the end of 12 months all the cases showed continued root growth and apical closure ( apexification ) with no evidence of periapical pathology. Conventional endodontic treatment was then performed. 70 7/21/2017 9:32 AM

71. BIODENTINE A new calcium silicate-based material, Biodentine , has been introduced. It has been developed as a permanent dentine substitute material whenever original dentine is damaged. Powder- tricalcium silicate and dicalcium silicate- the principal component of Portland cement and MTA. Calcium carbonate, calcium oxide, iron oxide, and zirconium oxide.  Liquid- calcium chloride and a water-soluble polymer. 7/21/2017 9:32 AM 71

72. Properties 7/21/2017 9:32 AM 72

73. Han and Okiji (2011) compared calcium and silicon uptake by adjacent root canal dentine in the presence of phosphate buffered saline using Biodentine and ProRoot MTA. The results showed that both materials formed a tag-like structure composed of the material itself or calcium- or phosphate rich crystalline deposits. The thickness of the calcium and silicon -rich layers increased over time, and the thickness of the calcium and silicon -rich layer was significantly larger in Biodentine compared to MTA after 30 and 90 days, concluding that the dentine element uptake was greater for Biodentine than for MTA.  7/21/2017 9:32 AM 73

74. Conclusion The practitioner should strive to achieve root development through apexogenesis wherever possible. If this treatment fails or pulp is necrotic, apexification should be initiated. However, the most important factors are debridement of the canal and closure of this space with a suitable material. These aspects allow the body to reorganize and repair the periapical tissues. 74 7/21/2017 9:32 AM

75. References Grossman LI: Endodontic practice, 10 edition, Philadelphia. 1981, Lea & Febiger Dentistry for Child and Adolescent. 6 th Edition McDonald R.E. and Avery D.R. Textbook of pediatric dentistry 3 rd edition. Marwah Tandon S. Textbook of Pedodontics . 2 nd ed. Delhi: Para; 2008. Principles and Practice of Pedodontics . Arathi Rao . 2 nd edition. Pediatric dentistry in children & adolescent, 8 th edit, McDonald, Avery & Dean, Elsevier pub. Camp JH, Barrett EJ, Pulver F. Pediatric endodontics . In: Cohen S, Burns RC, eds. Pathways of the pulp. 8th ed. St Louis: Mosby ; 2002. pp. 797–844. Ingle: Endodontics 6 th edition. 75 7/21/2017 9:32 AM

76. References A paradigm shift in endodontic management of immature teeth: Conservation of stem cells for regeneration. George T.-J. Huang. Journal of Dentistry 2008 Apexification : Case report. Peter Parashos . Australian Dental Journal 1997;42:(1):43-6 Camilleri J, Pitt Ford TR. Mineral trioxide aggregate: a review of the constituents and biological properties of the material. International Endodontic Journal, 39, 747–754, 2006. Endodontics , ingle & Bakland , 5 th edit, Mosby pub. Bhasker SN. Orbans oral histology & embryology, 11 th edn . St. louis : Mosby- year book. 1991. 76 7/21/2017 9:32 AM

77. 77 Study Advantages Heithersday , 1970 calcium hydroxide & methylcellulose has the advantage of decreased solubility in tissue fluids and a firm physical consistency Mitchell and Shankwalker 1958 osteogenic potential of calcium hydroxide when implanted into the connective tissue of rats Calcium hydroxide had a unique potential to induce formation of heterotopic bone in this situation Holland et al.1977 The reaction of the periapical tissues to calcium hydroxide is similar to that of pulp tissue Calcium hydroxide produces a multilayered necrosis with subjacent mineralization Schroder and Granath 1971 the layer of firm necrosis generates a low-grade irritation of the underlying tissue sufficient to produce a matrix that mineralizes It appears that the high pH of calcium hydroxide is an important factor in its ability to induce hard tissue formation Studies of calcium hydroxide products used for Apexification 7/21/2017 9:32 AM

78. Controversies on calcium hydroxide dressing changing 78 Study Findings Advantage Chawla 1986 it suffices to place the paste only once and wait for radiographic evidence of barrier formation Chosack et al 1972 the initial root filling with calcium hydroxide there was nothing to be gained by repeated root filling either monthly or after 3 months Abbot 1998 radiographs cannot be relied upon the ideal time to replace a dressing depends on the stage of treatment and the size of the foramen opening. It allows clinical assessment of barrier formation and may increase the speed of bridge formation 7/21/2017 9:32 AM

79. Time required for apical barrier formation in apexification using calcium hydroxide 79 Study Findings Sheehy and Roberts 1997 an average length of time for apical barrier formation ranging from 5 to 20 months Finucane and Kinirons 1991 calcium hydroxide apexification and found that the mean time to barrier formation was 34.2 weeks (range 13–67 weeks) Cvek 1972 infection and/or the presence of a periapical radiolucency at the start of treatment increases the time required for barrier formation Kleier and Barr 1991 presence of symptoms the time required for apical closure was extended by pproximately 5 months to an average of 15.9 months. 7/21/2017 9:32 AM

80. 80 TECHNIQUE/ MATERIAL INVESTIGATORS NO CASES OBSERVATIONS OUTCOMES Comparison of MTA plug with CH therapy El- Meligy and Avery, 2006 15 12 2 of CH teeth had become reinfected , but all teeth treated with MTA plug remained successful Comparison of MTA plug with CH therapy Pradhan et al, 2006 20 12 Periapical lesions resolved in 4.6 1.5 months for MTA group and in 4.4 1.3 months for CH group. Total treatment was completed in 0.75 0.5 months for MTA group and 7 2.5 months for CH group. MTA plug Pace et al, 2007 11 2 yrs 10 of 11 cases healed, and remaining case considered incomplete healing MTA plug Erdem and Sepet , 2008 5 2 yrs 4 of 5 teeth healed; 1 case in MTA was extruded MTA plug Sarris et al, 2008 17 11.7 yrs 94.1% clinical success, 76.5% radiographic success; 17.6% uncertain MTA plug Holden et al, 2008 20 12-44 month Healing rate was 93.75% 7/21/2017 9:32 AM

81. 81 TECHNIQUE/ MATERIAL INVESTIGATORS NO CASES OBSERVATIONS OUTCOMES MTA plug Nayar et al, 2009 38 12 months All teeth were clinically and radiographically successful MTA plug Annamalai and Mungara , 2010 30 12 months 100% success clinically and radiographically MTA plug Moore et al, 2011 22 Mean follow-up time 23.4 months Clinical and radiographic success rate of 95.5%; discoloration in 22.7% of teeth MTA plug Simon et al, 2007 43 12 months 81% healed MTA plug Witherspoon et al, 2008 78 Mean recall time was 19.4 months 93.5%of teeth treated in 1 visit healed, and 90.5% of teeth treated in 2 visits healed 7/21/2017 9:32 AM