Calcium hydroxide and it's application in dentistry

Calcium hydroxide

1. Calcium hydroxide

2. introduction Calcium hydroxide is a multipurpose agent, and there have been an increasing number of indications for its use. Some of its indications include: direct and indirect pulp capping, apexogenesis , apexification, treatment of root resorption, iatrogenic root perforations, interappointment intracanal dressing.

3. Ca(OH)2 is a white odorless powder with a molecular weight of 74.08. The material is chemically classified as a strong base with a high pH (12.5) Slightly soluble in water with a solubility of 1.2 g/l, at a temperature of 25˚C (Solubility decreases with temperature )

4. history Year 1838 - Nygren used ca(OH)2 for treatment of fistula dentalis Year 1851 - Codman used ca(OH)2 to preserve dental pulp Year 1920 -Hermann introduced calcium hydroxide for the treatment of infected root canals. Year 1930 - Calcium hydroxide became frequently used in the vital pulp therapies.

5. Year 1941 -The first literature regarding the successful healing using Calcium Hydroxide appeared. Year 1959 -The use of calcium hydroxide for apical closure was first reported by Granath . Year 1960 - Matsumiya and Kitumura demonstrated, in a dog whose infected root canals were packed with calcium hydroxide, showed a drastic reduction in the number of microorganisms.

6. Mode of supply Can be supplied in powder form – powder can be mixed with distilled water, saline solution to form a thick paste and applied as such. Can be supplied as two paste system, one base paste another catalyst paste. Can be supplied as single paste (visible light)

7. composition Base paste Catalyst paste Alkyl salicylate (1-methyl trimethylene disalicylate ) Inert fillers – titanium oxide 12-14% Radiopacifer – barium sulphate 32-35% Calcium tungstate or calcium sulphate 14-15% Calcium hydroxide 50-60% Zinc oxide 10% Zinc stearate 0.5% Titanium oxide Ethylene toluene sulphonamides and paraffin oil 39.5%

8. Mixing reaction Alkyl salicylate is dysfunctional chelating agent zinc oxide and calcium hydroxide, Amorphous calcium disalicylate is formed

9. Light Cured paste formulation: Dimethacrylate eg. Bis GMA Hydroxy ethyl methacrylate (HEMA) Calcium hydroxide Polymerizing activator Barium sulphate HEMA absorb water and release, calcium hydroxide to create an alkaline environment

10. Trade name Manufacturer Dycal ® Dentsply HydroxTM Bosworth Life Kerr VLC Dycal ® Dentsply

11. properties Physical Properties: L.C.T.E= low. Thermal conductivity= insulator Electrical conductivity=insulator. pH=12.5-12.8 Chemical Properties: Solubility- 0.4-7.8% Mechanical Properties: Elastic mod=0.37GPa Compressive strength >24 hr =10-37MPa Biologic Properties: Biocompatible.

12. Classification

13. According to Fava (1991) Ideal vehicle should: Allow a gradual and slow Ca² and OH- ionic release; Allow slow diffusion in the tissues with low solubility in tissue fluids; Have no adverse effect on the induction of hard tissue deposition Vehicles

14. Aqueous type of vehicles They have high degree of solubility USES Indirect pulp capping Direct pulp capping Pulpotomy Apexification subsequent to the apical curettage

15. Viscous type of vehicles They release Ca2+ and OH- in slow rate for extended period Lower solubility USES Apexification Treatment of large periapical lesions Interappointment dressing in cases of vital pulpectomy Endodontic retreatment after endodontic & surgical failures

16. Oily vehicles They are non water soluble Lowest solubility and diffusion

17. Clinical situations Requiring a rapid ionic liberation at the aqueous vehicle- containing beginning of treatment calcium hydroxide paste Gradual, uniform ionic liberation a viscous vehicle-containing paste. Pastes containing oily vehicles have restricted use and are only employed when very low ionic dissociation is needed

18. ACTION OF CALCIUM HYDROXIDE Induces mineralization Destruction of bacteria Dissolution of necrotic material/tissue dissolution property

19. Mechanisms of mineralization of Calcium Hydroxide

20. Antimicrobial activity: Release of hydroxyl ions in an aqueous environment (Siqueira 2001). It show extreme reactivity with several biomolecules. Damage to the bacterial cytoplasmic membrane; Protein denaturation Damage to the DNA (Siqueira & Lopes 1999): lethal effects on bacterial cells

21. Tissue Dissolution Properties 1988 by Hasselgren and colleagues reported that the tissue dissolving effect of NaOCl was enhanced by pretreatment of the tissue with Ca(OH)2. According to them Ca(OH)2 causes the tissue to swell and thus become more accessible to the NaOCl.

22. PULP Zone of Obliteration The pulp tissue immediately in contact with calcium hydroxide Usually completely deranged and distorted because of the caustic effect of the drug This zone consists of debris, dentinal fragments, hemorrhage, blood clot, blood pigment, and particles of calcium hydroxide

23. Zone of Coagulation Necrosis The tissue together with its plasma proteins within the zone of obliteration takes the brunt of the calcium hydroxide chemical thrust. Schroder’s layer of “firm necrosis” and Stanley’s “mummified zone.”

24. Zone of Dentin Bridge Formation This is an area of mineralization initiated by calcium hydroxide. No distinct structural configuration present in calcium hydroxide–initiated mineralization. This zone could range from 0.3 mm to 0.7 mm thickness.

25. Line of Demarcation A line of demarcation develops between the deepest level and the subjacent vital pulp tissue.

26. Periapical Area When using calcium hydroxide in root canal treatment as intracanal medicament, it might be accidentally extruded through the root apex. Barium sulfate (BaSO4) is added to calcium hydroxide paste as a radiopaque agent. Extrusion of calcium hydroxide paste containing barium sulfate beyond root canal can obscure the apex, and is not easily resorbed over time

27. Also barium sulfate enhances the release of inflammatory mediators responding to polymethylmethacrylate (PMMA) particles. Therefore, the healing process might be delayed.

28. APPLICATIONS OF CALCIUM HYDROXIDE

29. In operative dentistry AS A LINER Generally used as lining materials. Advantages, Therapeutic effects They have a rapid initial set in the cavity under the accelerating effect of moisture. They do not interfere with the setting reaction of the Bis-GMA resins. Initial set of the material in thin sections is sufficiently hard to resist the applied condensation pressures that are required even for the lathe cut amalgam alloy

30. AS A BASE It helps in repair of pulpal tissue It provides chemical insulation It replaces the lost portion of the dentin. Relatively low strength These bases are used only for their therapeutic benefits, chemical insulation

31. Intracanal Medicaments Application of calcium hydroxide paste at intervals of at least 7 days is able to eliminate and/or reduce the total number of bacteria surviving even after biomechanical preparation Anti-endotoxin agent Wide range of antimicrobial activity against bacteria, but has limited effect against E. faecalis and C. albicans.

32. The Effect on pro-Inflammatory cytokines Leads to denaturation of these pro-inflammatory mediators such as interleukin-1 α ( IL-1 α), tumor necrosis factor α ( TNF α) and calcitonin gene-related peptide (CGRP) Contributes to the resolution of peri radicular periodontitis

33. It considered the most effective dressing currently in use. However, it fails to consistently produce sterile root canals. Several factors impair its antimicrobial potency in the root canal system eg :complex anatomy will make packing difficult

34. INDIRECT PULP capping Procedure wherein the deepest layer of the remaining affected carious dentin is covered with a layer of biocompatible material in order to prevent pulpal exposure and further trauma to the pulp. - Grossman

35. Carious dentin actually consists of two layers having different ultramicroscopic and chemical structures. The infected dentin irreversibly denatured, infected incapable remineralization and hence should be removed. The affected dentin is reversibly denatured not infected and is capable of remineralization

36. The technique: Carious dentin is removed with a sharp spoon excavator and a hard set calcium hydroxide dressing is given to cover the remaining affected dentin. The remainder of the cavity is then filled with a reinforced zinc oxide eugenol cement or GIC. It is kept undisturbed for a minimum of 6-8 weeks. At the next appointment radiographs of the affected tooth are taken to assess the presence of reparative dentin

37. The temporary filling with calcium hydroxide is removed carefully. The reparative dentin layer is not disturbed. Over this another fresh application of calcium hydroxide is given over which a permanent filling is done with a suitable base

38. PULP CAPPING AGENT Ca(OH)2 generally accepted as the material of choice for pulp capping When directly applied to pulp tissue there is necrosis of adjacent pulp tissue and an inflammation of contiguous tissue. Beneath the region of necrosis, cells of underlying pulp tissue differentiate into odontoblasts and elaborate dentin matrix.

39. Three main products are: Pulpadent , Dycal , Hydrex (MPC) Pulpadent paste is considered to be most capable of stimulating early bridge formation. Hydrex has been considered that fast capable of forming a bridge. According to meadow and associates pure ca(OH)2 necroses 1.5mm pulp tissue. Stanley et al found that regular Dycal caused pulp mummification of 0.3-0.7mm where prisma VLC Dycal shown no inflammation

40. Prisma VLC Dycal consists of urethane dimethacrylate ,initiators and accelerators by which they bind to dentine and have higher resistant to acid dissolution

41. Pulp exposure capped with calcium hydroxide, Sixty days after applying calcium hydroxide, on the pulp tissue, a complete hard tissue barrier,

42. APEXIFICATION Canal is cleaned and disinfected, when tooth is free of signs and symptoms of infection, the canal is dried and filled with stiff mix of calcium hydroxide and CMCP. Commercial paste of calcium hydroxide ( eg. Calasept , Pulpdent , Hypocal,Calyxl ) may be used to fill the canals. The closure of apex may be partial or complete but consistently has minute communications with the periapical tissue.

43. From the histological view, The calcified tissue that forms over the apical foramen osteoid or cementoid material . Histological studies consistently report the absence of Hertwig’s epithelial root sheath (HERS). According to Grossman the residual undamaged pulp tissue, if there is any, and the odontoblastic layer associated with the pulp tissue resume. The matrix formation and subsequent calcification is guided by the reactivated HERS.

44. Obturation completed. 3month check shows resorption Of Ca(OH)2 Ca(OH)2 placed again. Ten-month re-evaluation. Apical barrier present

45. There is disagreement on how often the canal should be refilled with calcium hydroxide paste to produce apexification, and the decision seems to be empirical According to Tronstad et al. refilling every 3 to 6 months is favored. Some favors refilling only if there is radiographic evidence of resorption of the paste. Chosack suggested that after initial root filling with calcium hydroxide there was nothing to be gained by repeated root filling either monthly or after 3 months for at least 6 months

46. PULPOTOMY It is the most recommended pulpotomy medicament for pulpally involved vital young permanent tooth with incomplete apices. It is acceptable because -promotes reparative dentin bridge formation -radicular pulp vitality is maintained - allow uninterrupted physiological completion of root and root canals

47. Procedure Calcium hydroxide is applied to the amputated pulp and is tamped against the pulp with a sterile pledget of cotton. The pulp chamber should be filled to a depth of at least 1–2 mm with calcium hydroxide, on which a base of resin-modified glass ionomer cement or a flowable compomer is applied.

48. Calcium hydroxide can be used in many forms. 1)A paste made by mixing calcium hydroxide powder with one of the following media, saline, distilled water, local anesthetic solution, or glycerin 2) A fast-setting commercial paste, such as Dycal

49. At present calcium hydroxide pulpotomy technique cannot be generally recommended for primary teeth. Overstimulation of the primary pulp( highly alkaline calcium hydroxide ) cause metaplasia within the pulp tissue, leading to formation of odontoclasts result in internal resorption.

50. Sciaky and Pisanti have shown by means of radiographs that the calcium ions present in the dentin bridge that is formed during repair come from the systemic circulation not from the calcium hydroxide.

51. Root Canal Sealer RealSeal , Sealapex , Apexit , and Apexit plus are calcium hydroxide based sealers These sealers may also help in the formation of root-end hard tissue. Disadvantages limited antibacterial activity, poor cohesive strength, greater solubility marginal leakage

52. Weeping Canal Weeping canal is a canal from which constant clear or reddish exudation is appeared. This exudate is associated with a large apical radiolucency. The tooth is difficult to treat as when opened, exudate stops but it again reappears in next appointment. Signs and symptoms are varies from symptomless to tenderness to percussion and palpation.

53. Obturation of canals with exudates is contraindicated. For such teeth, application of calcium hydroxide in the canal after drying with sterile absorbent paper points is helpful. Its high alkalinity, which changes the acidic pH of periapical tissues to a more basic environment

54. Two other mechanisms have also been proposed: 1) build up bone in the lesion due to the calcifying potential of calcium hydroxide and 2) the residual chronically inflamed tissue is cauterized by the caustic action of calcium hydroxide

55. Perforation Management Calcium hydroxide has been recommended as a traditional agent to manage perforations Its usage still indicated to control infection, stop bleeding and as a temporary solution when inadequate time is available to perform a permanent repair.

56. root resorption It may be referred to as internal, external, or root end resorption. Resorption takes place in an acidic pH, Ca(OH)2 creates an alkaline environment in which this reaction is reversed and hard tissue deposition can take place. .

57. Frank and Weine reported on a technique using the Ca(OH)2-CMCP mixture for the nonsurgical treatment of perforating internal resorption. It results in the deposition of a cementum like or osteoid tissue at the site of the defect

58. avulsion Endodontic treatment of avulsed tooth with closed apex and an extraoral time of more than 60 minutes is initiated 7-10 days after the emergency visit. According to Trope, if endodontic treatment is delayed long term Ca(OH)2 is the treatment of or choice before obturation signs of resorption are present,

59. Cvek stated that long term Ca(OH)2 for avulsed teeth has high rate of success According to Andreasen et al. fracture strength of Ca(OH)2 filled roots reduced to half in about a year Due to the alkaline nature of Ca(OH)2 which neutralizes some of the acidic agents acting as bonding agents and thereby weakens dentine

60. Advantages Initially bactericidal then bacteriostatic. Promotes healing and repair. High pH stimulates fibroblasts. Neutralizes low pH of acids. Stops internal resorption. Inexpensive and easy to use.

61. Disadvantages Does not exclusively stimulate dentinogenesis. Does exclusively stimulate reparative dentin. Associated with primary tooth resorption. May dissolve after one year with cavosurface dissolution. May degrade during acid etching. Degrades upon tooth flexure. Marginal failure with amalgam condensation. Does not adhere to dentin or resin restoration.

62. CONCLUSION Calcium hydroxide has been used for different purpose in dentistry and available in different forms. Due to its high alkalinity and bactericidal properties. It is a material which is readily available, simple to prepare and restorable. Calcium hydroxide is still a material of choice which is widely being used for various reasons in Endodontics Despite its wide range of antimicrobial activity, calcium hydroxide is less effective against some species.

63. References Grossman’s ENDODONTIC PRACTICE 13TH Edition Basic dental materials John J Manapallil 4 th edition Calcium hydroxide: a review Alireza Farhad and Zahed Mohammadi Esfahan, Iran International Dental Journal (2005) Calcium Hydroxide in Endodontics:An Overview Raidan Ba-Hattab1, Manar Al-Jamie1, Haya Aldreib1, Lujain Alessa1, Mohammad Alonazi2 2016, Calcium Hydroxide in Dentistry Chettinad Health City Medical Journal 2016