4th 5th 6th generation of bonding agents

1. 4 th 5 th 6 th generating of bonding agents Done by: DR. ISRAA AWADH B.D.S.

2. Introduction DEFINITION Components IDEAL REQUIREMENTS Goals Challenges Classification Fourth generation Fifth generation Sixth generation Contents :

3. Introduction Dental bonding is a dental procedure in which a dentist applies a tooth-colored resin material (a durable plastic material) and cures it with visible, blue light . Tooth bonding techniques have various clinical applications including operative dentistry and preventive dentistry as well as cosmetic and pediatric dentistry, prosthodontics, and orthodontics

4. DEFINITION Bonding agents can be defined as material of low viscosity, when applied on the tooth surface forms thin film after setting. This thin film strongly bonded to tooth surface, on which the viscous composite restorative resin is applied. This sets forming an integrated resin restoration.

5. Components: ETCHING: dissolution of substrate, removed by rinsing to enhance intimate contact of adhesive. PRIMING : cleaning, structural alteration and increasing adhesiveness of the substrate. ADHESIVES: monomer (or related) that penetrates and establishes intimate contact with conditioned tissue substrate, polymerizes, and forms a strong bond between a such substrate and restorative material.

6. 1. The procedure must be safe and biologically acceptable . 2. The level of bond strength must be clinically significant to avoid discoloration at the margins and secondary caries . 3. The bond strength must be routinely achieved so that predictable results are obtained . IDEAL REQUIREMENTS 4. The bond must be established quickly in order to permit immediate finishing. 5. The bond must be stable in vivo for a clinically significant period of time.

7. 1 . The material should be retentive to dentin at a clinically acceptable level, and it should be able to withstand intraoral forces of occlusion and mastication. 2. The bond should be instantaneous once the material has set . 3. The material and technique must be biocompatible . Goals for effective dentin bonding materials 4. The material should resist the forces of polymerization shrinkage of composite resins and the coefficient of thermal expansion and contraction to eliminate microleakage. 5. The material should create a long-lasting bond to dentin

8. Dentin bonding is highly sensitive technique because: of fluid flow in the dentinal tubules deep dentin has more tubules (more fluid, hence lower Bond Strengths) varies from tooth to tooth in the same mouth (anterior teeth Shear Bond Strengths > molars)

9. Challenges of Bonding to Dentin Dentin is 17 percent collagen by volume. This collagen is inaccessible due to surrounding hydroxyl apatite crystals . Micromechanical retention with dentin depends only on dentinal tubules. These tubules contain fluid which would be an impediment to bonding . The number of tubules available for bond also varies depending on location, with deep dentin having more tubules than superficial dentin . Dentin bonding also varies with physiologic or pathologic changes in dentin, direction of tubules and the type of dentin available for bonding

10. 1 st generation adhesives (1960) 2 nd generation adhesives (late 1970s) 3 rd generation adhesives ( 1980s) 4 th generation adhesives (early 1990s) 5 th generation adhesives 6 th generation adhesives (late 1990 and early 2005) 7 th generation adhesives (in late 2002) Classification According to generation

11. primer and bonding resin applied to etched enamel and dentin by total etching the preparation with 40% phosphoric acid. T hey penetrate the intertubuler dentin for a depth of 2-4 micrometers forming a resin dentine interdiffusion zone or hybridization zone. Fourth-Generation adhesives:

12. hybridization is defined as “the phenomena of replacement of the hydroxyapatite and water of the dentin surface by resin, this resin in combination with collagen fiber , forms a hybrid layer (zone).”

13. They have the ability to bonds as strongly to dentine as to enamel (total etch) . Ability to bond to moist denti n . Multiple bottles system . 3 step application etching + primer +bonding Bonds strength 17 to 25 Mpa (high bond strength). Multiple substrate bonding to, porcelain and indirect composite . Ex: All-bond 2, Optibond FL and Scotch Bond multipurpose.

14. Examples: All-bond 2 Optibond FL ScotchBond multipurpose

15. These are essentially distinguished by being “two-step” system. Primer and bonding agent are available in single bottle. Easy to use and predictable. Reduced postoperative sensitivity . Fifth-Generation adhesives :

16. Examples: Optibond S olo & Optibond solo plus.

17. It was introduced in late 1990 and early 2005: Self-etching primers simultaneously condition (etch) and prime the dentin (and enamel ). sixth-Generation adhesives : Two primary types of self-etching primers exist: Two-step, self-etch adhesives, where an acidic self-etch primer is used instead of phosphoric acid to etch the enamel and dentin, followed by the application of the adhesive . 2. One-step "all-in-one" adhesives where etching, priming and bonding occur simultaneously through application of the self-etch primer.

18. • Simple to use . • Eliminates variables associated with “wet bonding ”. • Depth of etch is self-limiting . • Sensitivity is reduced, even with incomplete coverage (smear plugs still intact in areas not covered). Advantages of Self-Etching Primers:

19. • Bond strengths to enamel are typically lower than for total-etch adhesives . • Some materials do not adequately etch uncut enamel . • Bond strengths to auto-curing composites are poor. • Clinical performance not yet time proven; bond durability questionable, especially for all-in-one types ( hydrolysis). The bond strength to dentin and enamel is lower than the fourth and fifth generation system. Disadvantages of Self-Etching Primers:

20. There are still concerns about the quality of bonding of SE adhesives to enamel. If enamel is left unprepared, it is resistant to etching and adhesion with most SE adhesives . For preparations that include both dentin and enamel, it is recommended that the enamel should be prepared with a diamond bur to optimize the bond to the enamel . Currently, the use of an SE is contraindicated adhesive for - restoring Class IV incisal edge fractures. - esthetic facial veneering. diastema closures with direct composite resin and bonding porcelain veneers.

21. Literature is abundant comparing bond strengths of the total etch and self etch adhesives on enamel and dentin of human permanent teeth but there is a relatively paucity of data regarding dental adhesion to primary dentin . Higher bond strength values were obtained for permanent dentin compared to primary dentin. Similar results have been obtained in studies which had reported that: This lower bond strength values in primary teeth were related with the physical, micro morphological and chemical differences between primary and permanent teeth. Comparing the Bond strength between the primary and permanent dentin

22. Gel etchants need to be washed longer > liquid. Common wash times 5 - 15 sec Patient’s breath can reduce bond strength. All-purpose bonding agents contain large amounts of solvent (must be evaporated ). some notes keep in mind

23. Bond Strengths of all systems are lower for dentin than for enamel. Layering of bonding / flowable agents to thicken surface layer greatly reduces microleakage. Filled resins increase toughness of adhesive (not strength). For wet/moist bonding: best with use of cotton pellet. Refrigeration extends shelf life of all Dentin Bonding Agents.

24. Xeno III Clearfil se bond prompt l pop Examples:

25. The choice may be Confusing. It is easy for the clinician to believe that a new system is better over the old ones but this may not always be true . SO: Chemistry is more important than the company. Technique is more important than the material. What we have to choose:

26. Thank you I hope that you would not feel bored