Retrograde filling materials

Retrograde Filling Materials

1. 2 Retrograde Filling Materials Dr. Deepesh Mehta (Batch 2018-21)

2. Contents Introduction Ideal Requirements Retrograde Filling Materials Conclusion References 3

3. Introduction Resection of the root end during periradicular surgery results in an exposed apical dentine surface bounded by cementum with a root canal at its centre. Following the apical preparation, a retrograde filling material is usually used to seal the root-end cavity. Apicoectomy followed by retrograde filling is a well-established procedure to treat teeth with persistent periapical infections and teeth in which conventional root canal therapy has failed. 4

4. The main purpose of placement of a root end filling material is to provide an adequate apical seal. The most important objective of filling the root end preparation is to hermetically seal it from bacteria or byproducts. 5

5. Ideal Properties Sticks and adapts to the walls of the preparation. Easy to use. Dimensionally stable. Moisture-resistant. Insoluble in tissue fluids. Nonstaining . 6

6. Prevents leakage of micro-organisms and their products to the peri radicular tissues. Bactericidal or bacteriostatic . Biocompatible and cementogenesis promotor . Radiopaque. 7

7. Materials Amalgam Zinc Oxide- eugenol (ZOE) Cements Intermediate Restorative Material (IRM) SuperEBA Glass lonomer Cement (GIC) Diaket Gold Foil Gutta-percha 8

8. MTA (Mineral Trioxide Aggregate) Composite Compomers Bioceramics 9

9. Amalgam Amalgam has been used for a long time, but it has several problems. There tends to be marginal adaptation and filtration. There is also a problem with biocompatibility. Amalgams with a higher content of copper or zinc were also cytotoxic due to ion release. In addition, a galvanic current is produced due to contact with metal posts and crowns. 10

10. Finally, tattoos arise due to corrosion of amalgam/silver cones or leaving amalgam outside the cavity or removal of previous apicoectomies with amalgam/old silver cones. Amalgam studies show that success rates were as low as 44%, especially in studies longer than 5 years. 11

11. Zinc Oxide- eugenol (ZOE) Cements Zinc oxide-eugenol cements have been used in the past decade to replace amalgams; but they contain eugenol which, in contact with tissue fluids, is hydrolyzed and released. When ZOE comes in contact with water, it undergoes surface hydrolysis, producing zinc hydroxide and eugenol. This reaction continues until all the ZOE in contact with the free water is converted to zinc hydroxide. 12

12. Free eugenol has several dangerous effects depending on its concentration and length of exposure. It depresses vasoconstrictor response, and suppresses or enhances effects on the immune response. It can be an allergen and eliminates native oral microorganisms. It depresses vasoconstrictor response, and suppresses or enhances effects on the immune response. It can be an allergen and eliminates native oral microorganisms. 13

13. Other materials have been added to the basic ZOE mixture in an effort to increase the strength and radiopacity and reduce the solubility of the final material. Commercially available ZOE materials include intermediate restorative material (IRM; Dentsply Caulk, Milford, DE) and Super-EBA (Bosworth Company, Skokie, IL). 14

14. Intermediate Restorative Material ( IRM ) Intermediate Restorative Material is a modified ZOE cement that has been reinforced by the addition of polymethacrylate in the powder, eliminating the absorbability problem and eliciting a milder reaction. IRM consists of a powder containing greater than 75% zinc oxide and approximately 20% polymethacrylate mixed in equal parts with a liquid that contains greater than 99% eugenol and less than 1% acetic acid. 15

15. Studies show a better biocompatibility and higher clinical success rate than amalgam. IRM appears to be tolerated in the periradicular tissue, but it has no dental hard-tissue regenerative capacity. In a tissue tolerance study, it was found that IRM elicited little to no inflammatory effects after 90 days, which led to the conclusion that the oral tissue was just as tolerant of IRM as it was of any other retrograde filling material. 16

16. SuperEBA Super ethoxybenzoic acid cement is an improved IRM. Super-EBA consists of a powder containing 60% zinc oxide, 34% aluminum oxide, and 6% natural resins. It is mixed in equal parts with a liquid that contains 37.5% eugenol and 62.5% ortho-ethoxybenzoic acid. Ethoxybenzoic acid was developed in an attempt to alter the setting time and increase the strength of basic ZOE cements. Super EBA is pH neutral, has low solubility, and has less leakage than amalgam. 17

17. It produces minimal chronic inflammation in the apex. SuperEBA adapts very well to canal walls compared with amalgam, which appears to be well condensed but has poor adaptation. However, it is a difficult cement to manage when a large cavity has to be sealed, because of its short setting time, and it is also greatly affected by moisture and disintegrates in acidic pH. 18

18. In summary, superEBA cement is well tolerated by tissues, is fast setting, polishable and dimensionally stable, and provides a good apical seal. Disadvantages are that is difficult to manage, sensitive to temperature, moisture and acidic pH, and is only moderately radiopaque. It has no capacity to regenerate cementum. 19

19. For application, the liquid and powder are mixed in a 1:4 ratio. The powder is mixed into the liquid slowly in small increments. Once the rolled SuperEBA mixture loses its shine and the tip does not droop when picked up by a carrier, the mixture has the right consistency. 20

20. Glass lonomer Cement (GIC) Glass ionomer cement consists of aqueous polymeric acid, such as polyacrylic acid, plus basic glass powders, such as calcium aluminosilicate . The cement can be either light or chemically cured. GIC is very technique-sensitive however, there are the benefits of biocompatibility and GIC is adhesive to dentine. 21

21. As with IRM, it is greatly affected by moisture and blood during the initial setting time, resulting in increased solubility and decreased bond strength; this significantly occurred in unsuccesful cases. The cytotoxicity and tissue response is similar to ZOE-based cements The tissue response to GIC is considerably more favorable than to amalgam and similar to that with ZOE-based materials 22

22. Diaket Diaket (ESPE GmbH, Seefeld , Germany) a polyvinyl resin initially intended for use as a root canal sealer, has been advocated for use as a root-end filling material. It is a powder consisting of approximately 98% zinc oxide and 2% bismuth phosphate mixed with a liquid consisting of 2.2-dihydroxy-5.5 dichlorodiphenylmethane , propionylacetophenone , triethanolamine , caproic acid copolymers of vinyl acetate, and vinyl chloride vinyl isobutylether . 23

23. Leakage studies comparing Diaket to other commonly used root-end filling materials have shown it to have a superior sealing ability. When Diaket was used as a root canal sealer, biocompatibility studies showed that it was cytotoxic in cell culture276 and generated long-term chronic inflammation in osseous502 and subcutaneous tissues. However, when mixed at the thicker consistency advocated for use as a root-end filling material, Diaket has shown good biocompatibility with osseous tissues. 24

24. Gold Foil The use of gold foil as a root-end filling material was first reported in 1913 and 1920. It exhibits perfect marginal adaptability, surface smoothness and tissue biocompatibility. Implants of gold foil produce only mild tissue reaction. Gold Foil was found to be the best apical sealing material as far as the improvement in biting force is concerned. 25

25. When compared to IRM, composite resin, amalgam and glass ionomer , goldfoil was least toxic. The routine use of gold foil as a root-end filling material does not appear practical because it requires a moisture free environment, careful placement and finishing. 26

26. Gutta-percha Gutta-percha cones or pellets contain approximately 19–22% gutta-percha, 59–75% zinc oxide, and a series of other additives including waxes, colouring agents, antioxidants and metallic salts. Most of the earlier treatment failures with this material were related to poor adaptation of gutta-percha to the canal walls. Leakage can be seen in many surgical cases without using methylene blue. 27

27. Gutta-percha cones have shown evidence of toxicity in very sensitive tests in vitro. This is thought to be due to the high zinc oxide content. Therefore, the surgeon cannot rely on cold- or heat-burnished gutta-percha and finish microsurgery after apicoectomy without preparing a 3 mm deep apical microcavity and obturating it with a well-sealing and dimensionally stable biocompatible cement. 28

28. MTA Cement MTA consists of tricalcium silicate, tricalcium aluminate , tricalcium oxide, and silicate oxide. It also has bismuth oxide powder for radiopacity. The crystals are composed of calcium oxide and the amorphous matrix is composed of 33% calcium, 49% phosphate, 2% carbon, 3% chloride, and 6% silica. Calcium and phosphorous are the main ions. Iron is absent in the white MTA. 29

29. Hydration of the powder, which has a mean particle diameter of 10 nanometers, produces a colloidal gel that solidifies into a hard structure consisting of discrete crystals in an amorphous matrix. The compressive strength is quite low at 24 hours (40 MPa ) but it increases to 67 MPa at 21 days after mixing. The solubility of MTA is similar to amalgam and superEBA . Importantly, it is hydrophilic, so moisture and blood do not affect its setting. 30

30. Initially the pH is 10.2, but this increases to 12.5 at 3 hours after mixing. Its radiopacity (7.17) is reasonable, being higher than superEBA and IRM. It is currently the only available filling material that produces a cementum deposition layer over it, and only a minimal degree of inflammatory cell response, periodontal ligament regeneration thickness and osseous healing. 31

31. MTA is the best filling material available today in terms of biocompatibility, sealing ability, dimensional stability. Disadvantages are that, although moisture is required for its setting, during packing, isolation is critical because just one drop of liquid can remove it from the retrocavity . Also, its setting time is very long, radiopacity is not high, and clinically is the least scientifically tested cement, so far. 32

32. Composite Resin It should be used in cases when apicoectomy or retrocavity or both cannot be made due to: Cast posts that fill the canal all the way down. Previous apicoectomy that has resected the root up to the level of the post. Weak dentin walls remaining after apicoectomy that cannot support ultrasonic vibration, or short roots where apicoectomy will make the roots even shorter 33

33. Composite leaks less than superEBA , IRM and GIC. However, it is a material that is more sensitive to technique because moisture and blood contamination during the bonding/setting process reduces bond strength and increases leakage. 34

34. Compomers Geristore (Dent-Mat, Santa Maria, CA, USA) is a resin-reinforced glass ionomer hybrid in a dual-curing paste/paste formulation of a hydrophilic bisphenol -A- glycidyl methacrylate ( bis -GMA) with long-term fluoride release. It is less sensitive to moisture than conventional glass- ionomer cement, but a dry environment produces stronger bonds. 35

35. These materials have been shown to be equal or superior to IRM and equivalent to superEBA in their ability to reduce apical leakage. In Europe a composite resin-type material named Retroplast ( Retroplast Trading, Dybersovej , Denmark) was introduced in endodontic surgery with favorable long-term results. The root end management with these materials ( Geristore and Retroplast ) is different from that in endodontic microsurgery 36

36. The major disadvantage of these resin-type materials is difficulty in avoiding blood/moisture contamination. 37

37. Newer Materials >> 38

38. Bioceramics Bioceramics are a relatively new and potentially promising addition to the group of materials available for root-end filling. In vitro testing of EndoSequence Root Repair Material (ERRM; Brasseler , Savannah, GA) demonstrates biocompatibility and antimicrobial activity that is similar to MTA. ERRM is composed of calcium silicates, monobasic calcium phosphate, and zirconium oxide. 39

39. The material is hydrophilic, radiopaque, and has high pH. ERRM is available as a putty and a syringable paste. An advantage of RRM, based on clinical experience, is its handling properties, similar to that of Cavit (3M, St. Paul, MN USA). RRM is biocompatible, hydrophilic, insoluble, dimensionally stable, a high PH, has 30 minutes of working time, and as short as 2 hours setting time. 40

40. Bioaggregate Bioaggregate is a modification of MTA. It is a new bioceramic root repair and root-end filling material composed of a powder component consisting of tricalcium silicate, dicalcium silicate, tantalum pentoxide , calcium phosphate monobasic and amorphous silicon oxide and a liquid component of deionized water. 41

41. In a study investigating the cytotoxicity of Bioaggregate , Bioaggregate showed a significantly better inflammatory reaction and foreign body reaction than the MTA. An in vitro comparative study of the sealing ability of Diadent Bioaggregate and other root-end filling materials was done using methylene blue dye penetration technique; the results showed that microleakage was significantly less in Bioaggregate . 42

42. Biodentine It is a calcium silicate based material introduced in 2010 and is used as a material for crown and root dentin repair treatment, repair of perforations, apexifications , resorption repair and root-end fillings. The main component is a highly purified tricalcium silicate powder that contains small amounts of dicalcium silicate, calcium carbonate, and a radioopaquer . The flowable consistency of Biodentine penetrates dentinal tubules and helps in the mechanical properties of the interface. 43

43. Investigation of the bioactivity of Biodentine , MTA and a new Tricalcium silicate cement revealed that all three cements allowed the deposition of hydroxyapatite on the surface. This shows that all three materials are bioactive. An in vitro study to compare the sealing ability of MTA and Biodentine ; MTA showed the highest seal and the least dye absorbance. Biodentine showed a seal slightly less than MTA. 44

44. Ceramicrete This material has hydroxyapatite powder and cerium oxide radioopaque fillers. It is a self-setting phosphate ceramic that sets using an acid-base reaction to form a potassium magnesium phosphate hexahydrate ceramic matrix phase. A comparison of the root-end seal achieved using ceramicrete , bioaggregate and White MTA was done to study the prevention of glucose penetration; Both bioaggregate and ceramicrete showed similar sealing ability to MTA, with ceramicrete showing significantly better results than bioaggregate . 45

45. iRoot BP plus iRoot BP Plus (Innovative BioCeramix Inc., Canada) is a synthetic water-based bioceramic cement. It is available in ready to use premixed form and has a biocompatibility similar to MTA. 46

46. Generex A Generex A (Dentsply Tulsa dental, USA) is a calcium silicate based cement and is similar to MTA but the handling properties are different. Instead of water the cement is mixed with a special gel. The final consistency is similar to IRM like dough and easy to manipulate. 47

47. Endobinder EndoBinder ( Binderware , Brazil) is a new calcium aluminate cement. During production, free magnesium oxide and calcium oxide are eliminated to avoid expansion of the material and ferric oxide which can cause tooth discolouration is also eliminated. 48

48. Conclusion Many different materials have been advocated for use as root end filling materials, and each has specific advantages and disadvantages. However, from the biologic perspective of regeneration of the periradicular tissues, MTA, followed by Retroplast , appears to have a clear advantage over the other available materials. 49

49. Bioceramic materials may join this group, but require more clinical testing. Retroplast and other composite resin–based filling materials require meticulous hemostasis and a dry surgical field for optimum results. The most commonly cited disadvantage of MTA is its handling properties. Even when properly prepared, MTA is more difficult to place in the root-end cavity than most other materials. 50

50. No ideal retrofilling cement exists. IRM has been substituted by superEBA , but it continues to be the cement of choice in large cavities like strip perforations. SuperEBA is a reinforced IRM cement that provides a good apical seal. MTA is today's gold standard, and it is even easier and faster to work with than superEBA . Amalgam is no longer used. 51

51. References Cohen’s Pathways of the Pulp: 11 th Edition. Endodontic Microsurgery: Merino. Ingles Endodontics: 6 th Edition. Microsurgery in Endodontics: Syngcuk Kim. Kanchan Bhagat ., et al; “Root End Filling Materials and Recent Advances: A Review”; EC Dental Science 12.2 (2017): 46-57. J. Aqrabawi ; Sealing ability of amalgam, super EBA cement, and MTA when used as retrograde filling materials; BRITISH DENTAL JOURNAL, 188(5). Emre Bodrumlu ; Biocompatibility of retrograde root filling materials: A review; Aust Endod J 2008; 34: 30–35. 52