Liner Bases & Varnishes

Liner Bases & Varnishes short but in depth knowledge

1. PEOPLE’S COLLEGE OF DENTAL SCIENCE & RESEARCH CENTER DEPT. OF CONSERVATIVE DENTISTRY & ENDODONTICS 8 June 2016 1

2. CAVITY LINERs and BASEs Presented by- Dr NISHANT KHURANA PG Student Guided By:- Dr M.P. Singh & Dr Hemant Chourasia 8 June 2016 2

3. Contents Introduction Causes of pulpal pain Objectives for pulpal protection Classification of Intermediary bases Ideal requirements of intermediary bases Solution liners (varnish) Suspension liners Cement liners Cement base References 8 June 2016 3

4. Introduction 8 June 2016 4

5. STEPS OF TOOTH PREPARTION INITIAL TOOTH PREPARTION STAGE STEP 1:- OUTLINE FORM & INTIAL DEPTH STEP 2:- PRIMARY RESISTANCE FORM STEP 3:- RETENSION FORM STEP 4:- CONVENIENCE FORM FINAL TOOTH PREPATION STAGE STEP 5:- REMOVAL OF ANY REMAINING INFECTED DENTIN OR OLD RESTORATIVE MATERIAL STEP 6:- PULP PROTECTION STEP 7:- 2 ND RESISTANCE & RETENTION FORM STEP 8:- PROCEDURES FOR FINISHING EXTERNAL WALLS STEP 9:- FINAL FINISHING 9 STEPS WITH 1 GOAL 8 June 2016 5

6. PULP PROTECTORS :- LINER, BASES & VARNISH Main reason for using a liner or base is to protect the pulp or to aid pulpal recovery or both. 8 June 2016 6

7. Q Why does a tooth ache ?? 8 June 2016 7

8. the pulp communicates with the fluid inside the dentinal tubules , and if there is disturbance in the dentinal fluid it can be sensed by the pulp as pain 8 June 2016 8

9. Pulp Protection requires consideration of:- Sealing the smear layer Chemical protection Electrical protection Thermal protection Mechanical protection Pulpal medication OBJECTIVES OF PULPAL PROTECTION 8 June 2016 9

10. Sealing the smear layers Tooth preparation with rotary instruments generates cutting debris, some of which is compacted unavoidably into a layer on the cut surface. This layer of material is called SMEAR LAYER & is typical of any cut surface, dentine or otherwise. Its 25-30% porous & can not prevent Slow Long Term Diffusion 8 June 2016 10

11. 8 June 2016 11

12. Pulp protection against Thermal insult Electrical insult Chemical iritant Mechanical protection Pulpal medication 8 June 2016 12

13. Relation between dentin permeability & pulp protection Dentin permeability increase as remaining dentin thickness decrease towards the pulp. Factors which influence the need for pulp protection - depth of the cavity - location of walls & floor relative to the pulp horns - surface condition of dentin . 8 June 2016 13

14. Classification of Intermediary bases According to Marzouk 1. Varnishes 2. Liners 3. Sub base 4. Bases According to Sturdevant 1. Liners:-- Thin a) Solution liners (varnish 2-5 µm) b) Suspension liners (20-25 µm) - Thick – cement liners 2. Bases According to Charbeneau 1. Cavity varnish 2. Intermediary bases (liners) 3. Cement bases . According to Schwartz 1. Cavity sealers - varnish - resin bonding agents 2. Liners 3. Bases . 14 8 June 2016

15. IDEAL REQUIRMENTS The material should create an impervious layer. Biologically & Chemically compatible. Should not discolor tooth or restorative material. Should harden quickly. Should withstand the condensation forces. Should stabilize or diminish dentin permeability. Should be easily manipulated. 15 8 June 2016

16. Cavity liners Definition: Anusavice – Thin layer of cement such as calcium hydroxide suspension in an aqueous or resin carrier used for protection of the pulp. Sturdevant – Thin layers of material used primarily to provide a barrier to protect the dentin from residual reactants diffusing out of a restoration or oral fluids (or both) that may penetrate leaky tooth restoration interfaces . 8 June 2016 16

17. Liners can be classified on the basis of their film thickness into: - Thin film liners a) Solution liners (varnish 2-5 µm or 0.002- 0.005mm) b) Suspension liners (20-25 µm or 0.02-0.025mm) - Thicker film liners cement liners(200-1000 µm or 0.2 to 1 mm) 8 June 2016 17

18. VARNISHES (SOLUTION LINERS) Def :- Any liner based on non-aqueous solvents that rely on evaporation for hardening is designated as a solution liner(or Varnish). Copal or natural resin dissolved in non-aqueous volatile solvent, (ether, alcohol and acetone)  upon drying it will produce a thin film layer. ADVANTAGES:- flexible – dry rapidly . On the other hand, thick films tend to trap solvent during drying and become brittle . [2-5 µm] 8 June 2016 18

19. Copalite varnish occluding Dentinal tubules [Courtesy of SC Bayne, school of dentistry, University of Michigan, Ann Arbor, MI] 8 June 2016 19

20. Varnish [ copalite ] Composition Natural gum – copal resin Synthetic resin – nitrated cellulose Solvents Medicinal agents – chlorobutanol , thymol & eugenol . 8 June 2016 20

21. Functions Prevents microleakage . Reduces post-operative sensitivity. Prevents penetration of toxic materials. Does not act as an insulator. Properties: Neither possess mechanical strength nor provide thermal insulation . 8 June 2016 21

22. INDICATIONS: - Enamel & dentin walls – reduce the penetration of oral fluids around metallic restorations . - Over metallic restoration – reduce post-operative sensitivity - Dentinal walls – minimize penetration of acid from zinc phosphate cements. CONTRAINDICATIONS: 1- Under silicate cement → as it blocks the transfer of fluoride ions from silicate cement to tooth . 2- Under glass ionomer cement and polycarboxylate cement as it prevents or decrease their adhesiveness to tooth structure . 3- Under resinous restorations as acrylic resin and composite → as the residual monomer will dissolve the varnish destroying the integrity of the varnish film, which will be of no value to be used . 4- In moderately deep and deep cavities → as it does not provide thermal insulation property . 8 June 2016 22

23. METHOD OF APPLICATION Dry the cavity Soak a small cotton pellet with varnish Squeeze at one corner of cavity without moving it Soak it again and squeeze it again at another corner of cavity, do it till a continuous film is formed over cavity walls Dry it for 2 to 3 min Usually 3 applications are sufficient Also applied with camel brush Thickness 2 -5 microns 8 June 2016 23

24. Copal- F Protective varnish containing 5% Sodium Fluoride based on Copal gum for insulating exposed dentine and providing thermal barrier. 8 June 2016 24

25. Cervitec ® Plus-   Ivoclar Vivadent N.A. - Chlorhexidine Varnish -Protect exposed root surfaces -Treat of open dentin tubules -1% chlorhexidine and 1% thymol in a homogenous solution -Colorless, transparent clear varnish -Provides optimum esthetics in the anterior part of the mouth 25 8 June 2016

26. CavityShield ™ 5% NaF Varnish - 3M ESPE Company Bubblegum flavor Enhanced asepsis 8 June 2016 26

27. suspension liners Def : - Liners based on water have many of the constituents suspended instead of dissolved & are called suspension liners. Ca (0H) 2 or zinc oxide in a synthetic resin Water solvent based; H2O soluble 10-25 µm film; Used to line only the dentin [20-25 µm] 8 June 2016 27

28. Solution Liner/Varnish -Organic solvent based -H2O insoluble -2-5 µm -Used to line cavity up over cavosurface margins - They are flexible and dry rapidly Suspension liner -Water Solvent based -H2O soluble -20 – 25 µm - Used to line only the dentine - Dry more slowly and produce thicker film 28 8 June 2016

29. CEMENT LINERS Def :- Thicker liners that are selected primarly for pupal medication & thermal protection are sometimes identified as cement liner. [ 200-1000 µm = 0.2-1mm] 8 June 2016 29

30. FUNCTIONS: 1. Primary purpose  protective seal of exposed dentin surface .   2 . Electrical insulation (with newly placed amalgam restoration) from the electrical circuts with restorations in adjacent teeth .   3. Thermal insulation with metallic restoration 4. Pulpal medication COMPOSITION: - Suspension of calcium hydroxide - methyl ethyl ketone or ethyl alcohol - Methyl cellulose – thickening agent - acrylic polymer beads or barium sulfate - Calcium mono- fluoro -phosphate. 8 June 2016 30

31. Zinc oxide liner Used in moderately deep cavities . Palliative or obtundant effect Not used under composite restorations. 8 June 2016 31

32. Calcium hydroxide liner Forms reparative dentin Used under composite restorations In deep cavities In exposures or suspected exposures. 8 June 2016 32

33. Manipulation of Ca (OH) 2 Sqeeze equal parts of Ca (OH)2 paste, mix homogenously Make a bead and carry with applicator, allow it to flow on the surface of concavity created by caries and dry for 2-3 min If in Powder form carry with tweezer and repeat till it occupies required dimensions If in suspension form- Injectible ,Drop it on the site indicated Thickness-1-50microns for solution liners and suspension liners 20-25 microns 8 June 2016 33

34. Calcium hydroxide Glass ionomer Reinforced ZOE Components Paste with Ca(OH) 2 ,LC resin & polyphenols Powder(Al-silicate)liquid(polyalkenoate acid,LC resin) Paste (with ZnO ) paste (with eugenol ) Thermal conductivity Insulator insulator Insulator Solubility 0.3-0.5% high 0.08%(low) modest Compressive strength 138 Mpa 128 Mpa 71 Mpa Elastic modulus 588 Mpa 1820 Mpa ----- 8 June 2016 34

35. Cavity Bases Definition :- Anusavice – Layer of insulating, sometimes medicated, cement, placed in the deep portion of the preparation to protect pulp tissue from thermal & chemical injury. Marzouk – Insulating materials that can be used directly on certain areas of the dentinal parts of the preparation . Sturdevants - Bases(1 to 2 mm) are used to provide thermal protection for the pulp and to supplement mechanical support for the restoration by distributing local stresses from the restoration across the underlying dentin surface . [1-2mm] 8 June 2016 35

36. TYPES - High Strength Bases Provide thermal protection for pulp & mechanical support for the restoration. Eg:Zn phosphate,Zn poly carboxylate,Glass ionomer,RMGI - Low Strength Bases Have min strength & rigidity, Act as a barrier to irritating chemicals and to provide therapeutic effect to pulp. eg : Ca Hydroxide, ZnOE 8 June 2016 36

37. Historical Background : Before 1960’s Zn phosphate cement Reinforced ZnO /E 1970 polycarboxylate cement 1985-1994 GlC Light Cured GIC & compomers chemical adhesion , Good mechanical properties, fluoride release, command setting and rapid achievement of strength. 8 June 2016 37

38. Zinc phosphate Zinc polycarboxylate ZOE Calcium hydroxide GIC Composition And setting Reaction P-Zinc oxide, L- (phosphoric acid) P- Zinc oxide liquid( polyacrylic acid) P-zinc oxide L- eugenol Base paste Catalyst paste P, F-Al-Si glass L- polyacrylic acid p/L ratio 1.4 g/0.5 ml 1.5/1 6/1 by weight 1/1 3/1 by weight Setting time 2.5-8 min 6-9 min 4- 10 min 2.5- 5.5 min 3- 5 min Compressive strength 104 Mpa 55- 67 Mpa 4- 55 Mpa 10-27 Mpa 128 Mpa Diametral tensile strength 5.5 Mpa Slightly higher than ZnPO4 0.3- 5.3 Mpa 1 Mpa 6.6 Mpa Modul Of Elastcty 13.7 Gpa 2.4 -4.4Gpa Not brittle as ZnPO4 0.2- 5.4 Gpa 0.37 Gpa ….. 8 June 2016 38

39. General Applications Thermal and chemical insulation Temporary restorations – Zn OE Intermediate restorations – IRM Permanent restorations – GIC Temporary Luting – Type I ZOE Permanent Luting – GIC, ZnP , Zn Poly Carb 8 June 2016 39

40. Summary of pulp protection procedures Shallow Excavation [RDT > 2mm] Moderate Excavation [RDT 0.5 - 2mm] Deep Excavation [RDT < 0.5mm] Amalgam -/-/Sealer -/base/sealer Dycal /base/sealer Composite -/-/DBS -/-/DBS Dycal /-/DBS Gold inlays & onlays -/-/cement -/base/cement Dycal /base/cement Ceramics -/-/DBS, CC -/-/DBS, CC Dycal / -/DBS, CC (Medicament / Liner / Sealer) 8 June 2016 40

41. Schematic Diagram for Amalgam restoration 8 June 2016 41

42. References Philps ’ science of dental materials – 11 th edition Basic Dental Materials- Mannapallil Restorative dental materials – Craig Sturdevant’s art & science of operative dentistry – 5 th edition Operative dentistry – Marzouk 8 June 2016 42

43. Thank You 8 June 2016 43