Dentin bonding agents in dentistry .pptx

Dentin bonding agents are materials designed to create a strong and durable bond between restorative materials and the dentin surface. Unlike enamel, dentin is a moist, organic, and tubular structure, which makes bonding more complex and technique-sensitive. The development of dentin bonding agents has revolutionized adhesive dentistry by improving the retention of restorations, minimizing microleakage, and preserving tooth structure through more conservative cavity preparations. Over the years, advances in bonding technology—from early generation adhesives to modern self-etch and universal systems—have enhanced clinical performance, simplified application procedures, and increased the longevity of restorations.

1. Dentin bonding agents Presented by: Dr. Vaishnavi Chidrawar Dr Vaishnavi Chidrawar

2. contents Introduction History Adhesion Enamel etching Enamel bonding Role of Smear layer on bonding Evolution of dentine bonding agents upto 4 th generation Total etch technique Components of bonding agents Critical steps in bonding Dr Vaishnavi Chidrawar

3. introduction Today we are in the age of adhesive dentistry. Introduction of the acid etch, bonding techniques and resin based composites have contributed in a large way towards achieving goal. NEED FOR MORE ESTHETIC AND ADHESIVE MATERIAL Dr Vaishnavi Chidrawar

4. adhesion Adhesion is the force or the intermolecular attraction that exists between molecules of two unlike substances when placed in intimate contact with each other Chemical adhesion - primary valence forces such as covalent, ionic or metallic bonds. Physical adhesion - secondary valence forces like van der waals forces, the dispersion forces or hydrogen bonds. Mechanical adhesion - penetration of one material into a another at a microscopic level. Molecular entanglement- M-R-X groups Dr Vaishnavi Chidrawar

5. Substrate, adherend Adhesive Substrate, adherend 8 Adhesive joint ADHESIVE JOINT Dr Vaishnavi Chidrawar

6. Adhesive dentistry Dr Vaishnavi Chidrawar

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8. Theories of adhesion Solidified adhesive interlocks micromechanically with the roughness and irregularities of the surface of the adherend Includes chemical bonds between the adhesive and adherend. Primary- ionic and covalent Secondary- Hydrogen, dipole interaction Due to bonding between molecules. Polymers from each side of an interface cross over and react with each other. Electrical double layer forms at the interface between metal and polymer contributing to the bond strength. Dr Vaishnavi Chidrawar

9. Significant contrast in composition and structure of enamel and dentin greatly influence the prospects of bonding. Both organic and inorganic components vary in both the tissues. Enamel contains primarily hydroxyapatite, which has a high surface energy dentin is composed of two distinct substrates, hydroxyapatite and collagen, and has a low surface energy TOOTH AS A SUBSTRATE FOR BONDING Dr Vaishnavi Chidrawar

10. Enamel adhesion bvm Composition of enamel Primary component - hydroxyappetite Inorganic content – higher Homogenous in structure and composition Dr Vaishnavi Chidrawar

11. Natural surface smooth Inorganic fraction prism Normal enamel rod keywhole pattern Operatively prepared surface exposed enamel rods in tangential, oblique and longitudinal Dr Vaishnavi Chidrawar

12. enamel Enamel makes a uniform bonding substrate that consists of almost 90 vol% inorganic material with a very small amount of intrinsic water. 96% wt / 86% vol hydroxy appetite crystal 3% wt / 12% vol water 1% wt / 2% vol organic matrix Enamel etched on its rod ends provide better area for bonding compared to enamel etched on the side of the prisms. Fluoridated enamel has a low surface energy and is more difficult to bond compared to the non-fluoridated enamel Dr Vaishnavi Chidrawar

13. The major inorganic fraction - in the form of submicron crystallites, oriented in 3 dimensions, in which the spread and contiguous relationship of the crystallites contribute to microscopic unit, rod or prism Natural surface of enamel is smooth, and the ends of the rods are exposed as keyholes. Operatively prepared surfaces expose rods in tangential, oblique, and longitudinal planes Aprismatic ( prismless ) enamel at the outer surface - crystallites run parallel to each other and perpendicular to the surface. Dr Vaishnavi Chidrawar

14. BUONOCURE in 1955 used phosphoric acid for conditioning the enamel Acid Etching >50 percent -monocalcium phosphate monohydrate - which prevents any further dissolution, <30 percent - dicalcium phosphate dihydrate - that cannot be easily removed . Higher concentration of acid produces deeper tags, which being brittle give way leaving 10–25 μm depth similar to as obtained with the lower concentration of the acid. It is accepted that 30–40% concentration of the acid is the most effective Dr Vaishnavi Chidrawar

15. Type 1 Type 2 Type 3 Type 4 Type 5 Type 1 - prism cores were removed, leaving prism peripheries intact. Type 2 - prism cores remain intact while the prism peripheries are demineralized selectively. Type 3 - mixture of Type 1 & Type 2 configurations. Type 4 - A pitted enamel surface Type 5 - A flat, smooth surface after etching By Silverstone and Gwinnet honeycoomb appearence cobble stone appearence prismless enamel pitted over a large area of enamel high fluoride areas Dr Vaishnavi Chidrawar

16. Alternative acids Dr Vaishnavi Chidrawar

17. Acid Etching Types Dr Vaishnavi Chidrawar

18. TIME OF ETCHING The time for etching with 30% to 40% phosphoric acid - recommended as 15 seconds. However, enamel which is acid resistant because of a high fluoride content -60 seconds. Primary teeth also require longer etching time since the enamel is more aprismatic Dr Vaishnavi Chidrawar

19. dentin Dentin is a complex composite material with less than 50 vol% inorganic material, and with high water content (21 vol%) 70% wt / 50% vol hap 12% wt / 20% vol water 18% wt / 30% vol organic matrix—type I collagen Water : hydrophilic Higher percentage of water and organic matter ( I collagen). Heterogenous Dr Vaishnavi Chidrawar

20. Dentinal tubules with Dentinal fluid :- pressure of outward movement Arrangement of hydroxyapatite Smear layer Affect of aging Dentin in its superficial portion allows greater bond strengths than in the deeper portions. This might be because the superficial layer has more of solid dentin and less moisture contamination as compared to deeper portions. The presence of moisture in dentin is the major hurdle in achieving bonding. An important factor that influences the bonding to tooth surface is the presence of smear layer on cut dentin. Dr Vaishnavi Chidrawar

21. Each tubule - surrounded by - hypermineralized peritubular dentin. Intertubular dentin - less mineralized and contains more organic collagen fibrils. 96% of a superficial dentin - intertubular dentin 1% - fluid in the dentinal tubules 3% - peritubular dentin. Diameter of the tubules - 2.5 µm at the pulp side to 0.8 µm at DEJ. Number of tubules - 45,000/mm2 near the pulp to about 20,000/mm2 near the DEJ Near the pulp Peritubular dentin - 66% Intertubular dentin - 12% Dr Vaishnavi Chidrawar

22. It refers to the ease with which a substance can move into or across a diffusion barrier. Variation in permeability affects the bonding mechanism of dentin. DENTIN PERMEABILITY Dr Vaishnavi Chidrawar

23. Dentin bonding agent Dentin Bonding Agent A thin layer of resin between conditioned dentin and resin matrix of a composite restorative material. Dentin bonding agents are difunctional or multifunctional organic molecules that contain reactive group which interacts with dentin and the monomer of the restorative resin. Dr Vaishnavi Chidrawar

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26. Requisite for ideal bonding agent Dr Vaishnavi Chidrawar

27. STRUC TURE X M R Hydrophilic part: Displaces water & wets the surface. Permits penetration into porosities of dentin. Reacts with organic and inorganic portions ( phosphate esters Or carboxylic acid groups ) Capable of bonding to dentin. R- Spacer Is responsible for making the molecule large enough to keep methacrylate groups spatially located for optimal chemical reaction with the composites. Hydrophobic part: Reacts with the restorative resin Usually made of Methacrylate group Dr Vaishnavi Chidrawar

28. Adhesion to dentin Dr Vaishnavi Chidrawar

29. Composition of bonding agent Dr Vaishnavi Chidrawar

30. ETCHING/CONDITIONING An acidic agent that dissolves the inorganic structure in dentin resulting in collagen mesh that allows infiltration of an adhesive resin Removes smear layer and smear plugs Demineralizes intertubular dentin (1-5u) Exposes collagen fibers Demineralizes peritubular dentin. Decreases free surface energy Increase roughness Dr Vaishnavi Chidrawar

31. Primers Primers are adhesion promoting agents and contain hydrophilic monomer dissolved in solvents such as acetone and ethanol and or water. Hydrophobic part copolymerization with adhesive resin Hydrophilic part that has affinity for exposed collagen fibril

32. primers Functions:

33. Monomers • ifefbeyfebhfegf MONOMERS HEMA 4- META (methacryloyloxyethy Trimellitate anhydride) NTG- GMA- N- Tolylglycine glycidyl methacrylate BPDM- biphenyldimethacrylate PENTAdipenta erythrotol- penta acrylate monophosphate Primers - hydrophilic properties - phosphate, carboxylic acid, alcohol, or ester functional groups. HEMA - is a widely used primer monomer because of its high hydrophilicity and solvent-like nature. The rank of functional groups in their acidity is as follows: sulfonic acid > phosphonic > phosphoric > carboxylic > alcohol. If - acidic monomers increased in HEMA base - pH low to remove SL & etch underlying dentin. Representative of self etching primers are Phenyl-P (2-[ methacryloyloxyethyl ]phenyl hydrogen phosphate) 10-MDP (10-methacryloyloxydecyl dihydrogen phosphate) 4-MET (4-methacryloyloxyethyl trimellitic acid) 4-META (4-methacryloyloxyethyl trimellitic anhydride) MAC-10 (11-methacryloyloxy-1,1′-undecanedicarboxylic acid)

34. Adhesive resins Adhesive resin is an unfilled or semifilled resin which matches the resin in the composite but has lower viscosity to permit easy flow and penetration. Commonly used are: Methacrylic acid (MA) Methyl methacrylate (MM 4-MET- 4-methacryloyloxyethyl trimellitate anhydride 4-AETA - 4-acryloyloxyethyl trimellitate anhydride 10-MDP -10-methacryloyloxydecyl dihydrogen phosphate MAC-10 - 11-methacryloyloxy-1,10-undecanedicarboxylic acid Phenyl-P - 2-( methacryloyloxyethyl )phenyl hydrogen phosphate Di-HEMA- phospate and HEMA-phosphate Dr Vaishnavi Chidrawar

35. Mechanism of bonding Bonding to Inorganic Portion of Dentin between positive Ca2+ ions on dentin and negative charges on the group X Group X - phosphates, aminoacids and amino-alcohols or dicarboxylates phosphate bonding systems - most common ones employed. ‘Z’ - chlorine, a hydroxy or a phenyl group. Some adhesives that involve bonding to inorganic ions are: Bondlite , Scotch bond, J&J Bonding agents, Clearfil , Prisma Universal Bond, etc. Dr Vaishnavi Chidrawar

36. Bonding to the organic part of dentin amino (–NH) amido (-CONH) hydroxyl (–OH) carboxylate (–COOH) in the collagen of dentin. Removal of hydrogen from any of these groups allows combination with chemicals present in DBA. Compounds that have a capacity to react with one or more groups of collagen are isocyanates, carboxylic acid chlorides, carboxylic acid anhydrides and aldehydes Examples of the adhesives - bonding to organic part of dentin are Dentin Adhesit (isocyanate based), Gluma (aldehyde based), etc. Dr Vaishnavi Chidrawar

37. classification of bonding agents Dr Vaishnavi Chidrawar

38. DEPENDING ON THE NUMBER OF STEPS Dr Vaishnavi Chidrawar

39. First generation bonding system Dr Vaishnavi Chidrawar

40. According to generations First generation Buonocore - resin containing GPA- DMA could bond to HCl etched dentin surfaces. The bonds formed were water soluble and only 2-3 Mpa GPDM with acrylic resin- 1950s Dentin bonding agents- bifunctional Bowen in 1965 - N- Phenylglycine glycidyl methacrylate( NPG- GMA), a surface active comonomer Mediate water resistant bonds of resin to dentinal calcium. Dr Vaishnavi Chidrawar

41. B onding mechanism: Chelation with calcium on the tooth surface to generate water resistant chemical bonds of resin to dentinal calcium. Bond Strength : 2- 3 Mpa Eg : Cervident ( S.S White, Lake wood, NJ) First commercially available bonding agent. Cosmic bond ( Amalgamated Dental Company) Palakav ( Kulzer, USA). Dr Vaishnavi Chidrawar

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44. Second generation bonding system Dr Vaishnavi Chidrawar

45. In 1978, the Clearfil Bond System F( Kuraray, Osaka, Japan) was introduced in Japan, - the first product of the second generation adhesives. Phosphorous esters of methacrylate derivatives. Second generation bonding system Agents used in this generation: Clearfil bond system F. Scotch bond dual cure( 3M ESPE). Bondlite ( Kerr). Prisma Universal Bond( Johnson and Johnson). Dr Vaishnavi Chidrawar

46. Mechanism of action: Surface wetting phenomenon and ionic interaction between negatively charged phosphate groups in the resin and positively charged calcium in the smear layer. Bond strength: 5 Mpa , which was considerably low Dr Vaishnavi Chidrawar

47. Disadvantages: Dr Vaishnavi Chidrawar

48. Third generation bonding system Dr Vaishnavi Chidrawar

49. THIRD GENERATION Etching - Fusayama et al in 1979. Etched surface- - - micromechanical retention of composite by allowing penetration of bonding agent into opened dentinal tubules. Mix of hydrophobic and hydrophilic agents— HEMA and 10 MDP- Dr Vaishnavi Chidrawar

50. Components are : a) Dentin- conditioner b) Dentine primers / adhesion promoting agent c) Bonding agent Smear layer was modified / fixed used oxaltaes Dr Vaishnavi Chidrawar

51. Modification of smear layer to improve its properties. Removal of smear layer partially without disturbing the plugs that occluded the dentinal tubules. Mechanism of action: The phosphate primers modifies the smear layer by softening it; after penetration it cures forming a hard surface Bond strength : 9- 15 Mpa. Dr Vaishnavi Chidrawar

52. More complex requiring 2- 3 applications So the main problem was the longevity of the maintenance of the bond. These are technique sensitive and time consuming. • Decrease in bond strength with time. • Increase in microleakage with time. Increased bond strengths More effective in reducing microleakage Primarily relied on mechanical means Better clinical performance Reduced need for retention form in tooth preparation Can be used for porcelain and composite repairs Erosion, abrasion and abfraction lesions can be treated with minimal tooth preparation. Third Generation Dr Vaishnavi Chidrawar

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54. Fourth generation Total – etch concept (3 step) “ideal bonding agent” Bertolloti “ total etch, total seal, total success 1980s and 1990s Dr Vaishnavi Chidrawar

55. Fourth generation Introduced in late 1980s by Bertolotti and Kanca Fear of damage to pulp- discouraged as very little acid actually penetrates dentin Mild acids- didn’t remove smear layer completely Involved phosphoric acid etching of dentin as well as enamel. Dr Vaishnavi Chidrawar

56. Mechanism of action : Etching removes smear layer completely , opens the tubules upto 7.5 microns and increases the permeability. Primer wets & penetrates the collagen meshwork and increases its surface energy and wettability into which the resin flows. Bond strength : 17- 30 Mpa Dr Vaishnavi Chidrawar

57. Etchant Primer Adhesive + + 3 step total etch 4 th Generation Dr Vaishnavi Chidrawar

58. Characterized by - Complete removal of smear layer Total etch technique Wet bonding Hybrid layer formation Total etch and Complete removal of smear layer Dr Vaishnavi Chidrawar

59. FOURTH GENERATION Multiple bottles- cumbersome. Post- operative sensitivi ty Technique sensitive. Over drying or Over wetting can interfere with the effective bonding. Good bond strength Similar bond strengths to both enamel and dentin No reduction in bond strength on moist surfaces Can bond to other surfaces (metals, amalgam, porcelain) Dr Vaishnavi Chidrawar

60. Fifth generation bonding system “ one bottle” systems / self priming systems Dr Vaishnavi Chidrawar

61. Objective - Separate etch and rinse phase(total etch) followed by application of combined primer- adhesive resin solution. Bond strength: 17 – 24 MPa. Etchant Primer Adhesive Primer and adhesive FIFTH GENERATION Fifth generation Dr Vaishnavi Chidrawar

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63. Technique sensitive. Over drying or Over wetting can interfere with the effective bonding. Good bond strength Less post operative sensitivity Less no of applications - easy to use Dr Vaishnavi Chidrawar

64. Sixth generation bonding system Self – etching primers Dr Vaishnavi Chidrawar

65. Sixth Generation Bonding agents: Primer and etchant are combined in one step ( Self etching primers) Type I Two step/ Non rinsing conditioner/ Self etch primer systems Type II One step/ Self etching adhesives/ All in one systems Dr Vaishnavi Chidrawar

66. Etchant Primer Adhesive Etchant Adhesive Self etching primer All in one adhesive Dr Vaishnavi Chidrawar

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68. SIXTH GENERATION Type I Two step/ Non rinsing conditioner/ Self etch primer systems : NRC followed by Prime and Bond NT (Dentsply) Clearfil SE Bond Clearfil Liner Bond IIV. Tryian( BISCO, Inc, Schaumburg,) Simplicity( Apex Dental Materials, Inc, Sandwich, IL) UniFil Bond(GC America, Alsip, IL) OneCoat Self- Etching Bond(Coltene) AdheSE( Ivoclar Vivadent) Dr Vaishnavi Chidrawar

69. 6 th Generation Type II. Prompt L Pop( 3M) Touch and Bond ( Parkell) Brush and Bond( Parkell) Xeno III( Dentsply Caulk) One up Bond F( J Morita, Kuraray) Dr Vaishnavi Chidrawar

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71. Seventh generation bonding system All in one system Dr Vaishnavi Chidrawar

72. They are truly all in one self etch adhesives that require no mixing. 72 Available both as light cure and dual cure type. All three components are combined in a single bottle. 7 TH generation bonding agents are slight modification of type II 6 TH generation bonding agent. The features are: More acidic (pH < 1) Single bottle containing acidic adhesive Unprepared enamel may require etching with phosphoric acid Solvent is water, e.g. G-Bond and i -Bond Dr Vaishnavi Chidrawar

73. i Bond Heraeus Kulzer Single step no mix bonding system Five in one solution : Etch Disinfect Desensitize Prime Bond - Composition : Matrix – UDMA ; 4- META Solvents – Acetone ; water Photoinitiators – Camphoroquinone Dr Vaishnavi Chidrawar

74. G bond COMPOSITION Advanced formulation of Phosphoric acid ester monomer, 4- MET monomer, nanofilled particles, Acetone & water as solvent used. Mechanism of action This decalcifies the tooth, provides wetting property, diffuses monomer into the tooth structure, then polymerizes and hardens when light- cured and creates an ionic bond with the apatite in the tooth structure. Based on nano interaction technology Dr Vaishnavi Chidrawar

75. monomer : Consistent bond to enamel. consistent bond to dentin Nanointeraction technology Non- conventional interface with the dentin – a “Nano Interaction Zone” (NIZ) with minimal decalcification and almost no exposure to collagen fibres. Ionic bond wit h hydroxyapatite of tooth structure,

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77. Eighths generation bonding system Dr Vaishnavi Chidrawar

78. 8 th generation In 2010, voco America introduced voco futurabond DC as 8th generation bonding agent, which contains nanosized fillers. In the new agents, the addition of nano- fillers with an average particle size of 12 nm increases the penetration of resin monomers and the hybrid layer thickness, which in turn improves the mechanical properties of the bonding systems Composition of eight-generation bonding agents - combination of three functional monomers (4-META, MDP, and MDTP), notably excluding HEMA, ensures excellent stability and exceptional bond strengths not just to tooth tissue but to all indirect substrates, including composites, precious and non-precious alloys Dr Vaishnavi Chidrawar

79. EIGHTH GENERATION One- Step, Dual- Cured Self-Etch Adhesive in Unit- Dose Blister Packs- VOCO America’s A single- dose delivery system enhances the convenience of nano- reinforced, eighth- generation Futurabond DC. a Futurabond DC Dual-Cured  It takes only 35 seconds from start to finish.  It needs only one coat.  In unit dose providing freshest chemistry each time.  It does not need to be refrigerated or shaken before use.  No sensitivity.  Over 30 MPa bond strength to dentin and enamel Dr Vaishnavi Chidrawar