1. Pulpal Protection: Clinical Indications for Sealers, Liners, and Bases

2. Clinical symptoms of caries-pain Pulpal physiology-review (Discussion of speed of caries progression) Appropriate restorative treatment techniques: Sealers Liners Bases Overview

3. Caries presents in degrees of severity (initial, moderate, advanced). Symptoms are variable and patient-specific. Vitality testing is helpful in determining course of action. Vascularity is the major concern with regard to vitality and ability to heal after assault. Ultimately excavation and clinical judgement leads to appropriate treatment.

4. No pain Pain on stimulation, short duration (10-15 sec. upon stimulus removal) Pain on stimulation, long duration (lasting longer than 15 sec. after removal of stimulus) Constant pain This is reversible pulpitis ? This is irreversible pulpitis ? This tooth must be necrotic?

5. Causes of pulpal pain Inflammatory response (increased intrapulpal pressure on nerve endings) No inflammation (Hydrodynamic theory- dentinal permeability) Bacterial assault via dental caries Thermal sensitivity

6. Etiology of Pain: Rapid fluid movement within the dentin tubule surrounding the odontoblastic process creates a change in pressure and results in pain. No fluid movement (or slow) inside the dentinal tubule simply means no postoperative sensitivity Hydrodynamic Theory If tubules are occluded, fluid flow will be prevented, and therefore no pain. Bottom line: operative procedures should focus on sealing the tubules (pulpal hydrodynamics theory), and not insulating them (direct shock theory).

7. Dental Pulp Response Irritants which momentarily contact dentin and are immediately removed normally cause “twinges” of pain. Continued contact or repeated insults can cause hyperemia and inflammation of the pulp this results in increased blood flow and blood volume inside the pulp chamber pain results from this blood being “contained in the pulp” and trapped inside the dentinal walls, and the drainage of blood is limited due to the constricted apical foramen.

8. ReversibleIrreversible Pulpitis Reversible and Irreversible Pulpitis Reversible pulpitis = pulpal pain which subsides after 10-15 seconds upon removal of the irritant Can normally be resolved with a restorative procedure Irreversible pulpitis - pulpal pain (spontaneous or elicited by an irritant) lingers longer than 15 seconds after removal of irritant.(cold) Infection of the pulp may require endodontic therapy (root canal) If untreated, then suppuration (pus) and pulpal necrosis can occur with spontaneous or a continual throbbing pain elicited by heat (relieved by cold) until finally there is no response. Root canal or extraction is indicated

9. Carious tooth, asymptomatic ( no indication of pulpal pathology ) symptomatic Short duration Long duration spontaneous endodontics extraction Indirect RMGI pulp cap Temporary fill for 3 mo. Indirect pulp cap RMGI, permanent fill Do not crown CaOH direct pulp cap & RMGI (mechanical exposure) Fill & observe????? For amal.: RMGI if deep. Gluma if shallow. For comp.: etch, prime, bond, RMGI if deep N.V. Pulp testing N.V. Pulp testing Excavate & pulpotomy or ectomy Excavate and fill V. Pulp testing N.V. Pulp testing By C. Rodriguez D.M.D. asymptomatic N.V. Pulp testing

10. Tertiary Dentin Reparative dentin (tertiary dentin) is formed by replacement odontoblasts (secondary odontoblasts) in response to irritants (i.e. attrition, abrasion, erosion, trauma, caries, operative procedures) if the assault is not too rapid. Localized deposit of reparative dentin on the pulp chamber wall occurs next to the injured area Reparative dentin is highly atubular making it resistant to further insult by irritants Reparative or tertiary dentin is also commonly referred to as a defensive reaction to moderate injury

12. Tertiary Dentin Typical sequence in the formation of tertiary dentin after tooth preparation : tooth preparation within 1.5 mm of the pulp some of the odontoblastic cell processes that are cut die (along with the odontoblasts) forming dead tracts (empty dentinal tubules due to death of odontoblast) In 15 days, new odontoblasts are formed from mesenchymal cells of the pulp and these new replacement odontoblasts lay down and start forming reparative dentin In about 1 month, we find this reparative dentin is structurally and chemically different from the previous primary & secondary dentin

13. Pulpal irritation that occurs during or after operative procedures may result from: Heat generated by rotary instruments, desiccation Some ingredients of various materials Thermal changes conducted through restorative materials Forces transmitted through materials to the dentin Galvanic shock The ingress of noxious products and bacteria through microleakage (Dentin tubules)

14. Key to minimizing adverse pulp reaction during preparation: o Light pressure (handpiece) o Sharp instruments (friction of dull bur) o Preservation of tooth structure (RDT) o Proper isolation during procedure (bacterial toxins) o Adequate air-water coolant spray (desiccation, heat) o Careful manipulation of materials (noxious chemicals)

15. Electrical conductivity-the measure of the relative rate of electron transport through a material galvanic shock-electrochemical cell in which electrical current may flow, stimulating nerves in the pulp Thermal conductivity-property of a material to conduct heat energy (amalgam has high TC, composite has low TC) Thermal diffusivity-ability of a material to conduct thermal energy relative to its ability to store thermal energy; measure of transient heat-flow (TD of gold, amalgam >composite>enamel) thermal shock-temp change transferred from oral cavity through restorative material Pulpal irritation that occurs after operative procedures may result from:

16. Thermal Diffusivity (mm2/sec) Dental bases 0.2 mm2/sec. Amalgam 9.6 mm2/sec. Composite 0.7 mm2/sec. Enamel 0.5 mm2/sec. Dentin 0.2 mm2/sec.

17. Remaining dentin thickness (RDT) is the single most important factor in protecting the pulp. In-vitro studies reveal: 0.5 mm of remaining dentin thickness (RDT) will reduce the effect of toxic substances by 75% 1 mm thickness by 90% 2 mm thickness little or no pulpal reaction

18. But what happens when the tooth does not have the required RDT after caries removal?

19. Dental restorative materials have been developed to provide pulpal protection or prevent pulpal reaction. This is an adaptation of the preparation prior to receiving the final restorative material. Sealers-ideally provide a seamless transition from restoration to tooth structure by providing a protective coating for freshly cut tooth structure of the prepared cavity. Liners-placed with a minimal thickness, less than 0.5mm and provide therapeutic benefit such as fluoride release, dentinal seal through adhesion, and/or antibacterial action that promotes pulpal health. Bases- used as dentin replacement material, allowing for less bulk of restorative or blocking out undercuts for indirect restorations.

20. Stages and Steps of Tooth Preparation for Amalgam Initial Tooth Preparation Stage Step 1: Outline Form and Initial Depth Step 2: Primary Resistance Form Step 3: Primary Retention Form Step 4: Convenience Form Final Tooth Preparation Stage Step 5: Removal of Remaining Infected Dentin and Old Restorative Material Step 6: Pulp Protection Step 7: Secondary Resistance and Retention Forms Step 8: Procedures for Finishing External Walls Step 9: Final Procedures (clean, inspection, sealing)

21. Stages and Steps of Tooth Preparation for Composite Initial Tooth Preparation Stage Step 1: Removal of carious enamel Step 2: Removal of carious dentin Step 3: Convenience form Final Tooth Preparation Stage Step 4: Removal of remaining infected dentin and preexisting restorative material Step 5: Pulp Protection Step 6: Procedures for finishing external walls (beveling) Step 7: Final Procedures (clean, inspection)

22. Once a restoration has been placed, under even ideal circumstances, materials constraints can deleteriously affect the tooth.

23. Linear Coefficient of Thermal Expansion (LCTE) = change in length /unit length for a 1 degree C change in temp. material x10-6/degree C Tooth structure 9-11 Dental amalgams 25 Glass Ionomers 20-25 Composites28-35 Anterior and flowable composites35-50

24. Thermal Expansion can result in Percolation –the movement of fluids through porous materials as in the cyclic ingress and egress of fluids at the restoration margin. During cooling: contraction Amalgam contracts faster than the tooth structure and recedes from the preparation wall, allowing the ingress of oral fluids During heat: expansion The fluid is expressed (egress)

25. The interfacial gap which forms between the tooth and restoration may allow microleakage to occur. Bacteria, fluids, molecules, ions can pass along the interface between the restoration and preparation wall Can cause marginal discoloration, secondary caries, and pulpal pathology

26. Dental restorative materials have been developed to provide pulpal protection or prevent pulpal reaction. This is an adaptation of the preparation prior to receiving the final restorative material. Sealers-ideally provide a seamless transition from restoration to tooth structure by providing a protective coating for freshly cut tooth structure of the prepared cavity. Liners-placed with a minimal thickness, less than 0.5mm and provide therapeutic benefit such as fluoride release, dentinal seal through adhesion, and/or antibacterial action that promotes pulpal health. Bases- used as dentin replacement material, allowing for less bulk of restorative or blocking out undercuts for indirect restorations.

27. The very first cavity sealers were varnishes used on cut tooth surfaces Used for decades to fill of the gap between amalgam and tooth until corrosion formed. Still in use today by some practitioners. Thin (2-5 µm) layer Dry solution of natural gum (copal), rosin, or synthetic resin is dissolved in an organic solvent (acetone, chloroform, ether) Cavity Sealers: 1)Varnishes 2)Bonding Agents 3)Dentin Desensitizers

28. Bonding provides retention and prevents leakage around enamel margins of restorations (monomers polymerize and interlock ) Bonding to enamel is a relatively simple process, without major technical requirements or difficulties (etching increases surface energy) Bonding to dentin presents a much greater challenge Dentin adhesion relies primarily on the penetration of adhesive monomers into the network of collagen fibers Cavity Sealers: 2) Enamel and Dentin Bonding Systems

29. Amalgam is hydrophobic, dentin is hydrophilic Need a “wetting agent” between the hydrophobic and hydrophilic surfaces The key wetting primer agent in most amalgam bonded systems is 4-methyloxy ethyl trimellitic anhydride or better known as “4-META” (there is a decreased leakage of fluids when compared to noncoated or varnish-coated amalgam cavity walls Clinical studies: no evidence of reduced postop sensitivity) Cavity Sealers: Amalgam Bonding

30. Amalgam bonding should not be used as the sole means of retention Amalgam bonding may be effective for supplementing mechanical resistance features A filled amalgam bonding system should be preferred Adequate moisture control and meticulous attention to product instructions are necessary to duplicate the success demonstrated by clinical trials Cavity Sealers: Amalgam Bonding

31. GLUMA 5% glutaraldehyde and 35% 2-hydroxyethyl-methacrylate (HEMA) Occlusion of the dentinal tubules by precipitation of plasma proteins limits the potential for tubular fluid movement and resultant sensitivity Desensitizers are effective disinfectants i.e.: glutaraldehyde Cavity Sealers: 3) Desensitizer Agents

32. Gluma desensitizing agent Preparations improved bond strengths of dentin bonding agents & some cements More recently, dentin-desensitizing solutions also have been used under amalgam restorations and crowns to prevent postoperative sensitivity Schwartz, RS et al1998 The use of a dentin desensitizer before cementing full-coverage crowns is supported by studies that showed dentin-desensitizing solutions do not interfere with crown retention, regardless of the type of luting cement used Cobb, DS et al 1997; Swift, EJ et al 1997 Cavity Sealers: Desensitizer Agents- other applications

33. Dental restorative materials have been developed to provide pulpal protection or prevent pulpal reaction. This is an adaptation of the preparation prior to receiving the final restorative material. Sealers-ideally provide a seamless transition from restoration to tooth structure by providing a protective coating for freshly cut tooth structure of the prepared cavity. Liners-placed with a minimal thickness, less than 0.5mm and provide therapeutic benefit such as fluoride release, dentinal seal through adhesion, and/or antibacterial action that promotes pulpal health. Bases- used as dentin replacement material, allowing for less bulk of restorative or blocking out undercuts for indirect restorations.

34. A barrier that protects the dentin from noxious agents from either the restorative material or oral fluids. Used to medicate the pulp when suspected trauma has occurred The desired pulpal effects include sedation and stimulation, the latter resulting in reparative dentin formation Cavity Liner

35. Initial electrical insulation Some thermal protection May provide fluoride release(GI, RMGI) Can adhere to tooth structure (GI, RMGI0 May be antibacterial in promoting pulpal health(CaOH) Cavity Liner-normal thickness <0.5mm

36. Dycal: CaOH Vitrebond: GI Fuji Lining LC: RMGI Cavity Liner-normal thickness <0.5mm

37. The specific pulpal response desired dictates the choice of liner If the removal of infected dentin does not extend deeper than 1.0 to 2.0 mm from the initially prepared pulpal or axial wall (amalgam prep), usually no liner is indicated If the excavation extends into or within 0.5 mm of the pulp, a calcium hydroxide liner usually is selected to stimulate reparative dentin Cavity Liner-normal thickness <0.5mm

38. Basic pH stimulates reparative dentin formation Note: humidity or wetness will accelerate the set of Dycal (make sure tooth surface is relatively dry) Cavity Liner-normal thickness <0.5mm: Calcium Hydroxide Place Dycal sparingly only where you need it.

39. Used in the deepest part of the preparation (<.5 mm of the pulp) CaOH raises the pH of the oral environment (bacteria grows in an acidic environment) Recent evidence suggests CaOH may have a stimulating effect on dentin remineralization through the solubilization of noncollagenous proteins, including growth factors. High concentrations CaOH (pH > 11) is cytotoxic Cavity Liner-normal thickness <0.5mm: Calcium Hydroxide With Dycal the initial response after exposing pulp tissue to CaOH is necrosis to a depth of 1mm or more. (The high pH helps to coagulate hemorrhagic exudate of the superficial pulp.) After necrosis, neutrophils infiltrate and within weeks to months the necrotic zone undergoes dystrophic calcification which appears to be a stimulus for dentin bridge formation. Craig’s Restorative Dental Materials 13 th ed.p.122

40. Traditional CaOH undergoes a chemical auto-cure chemical setting reaction Problems with Dycal: It degrades over time creating a “trampoline effect”, so an amalgam restoration loses it’s foundational support Traditional CaOH liners may continue to dissolve over time (due to microleakage or dentinal fluid present) and can lose as much as 10-30 % of their original volume Light-cured CaOH (i.e. VLC Dycal) has overcome some of these weaknesses, but it is not as effective as chemical auto-cured CaOH Cavity Liner-normal thickness <0.5mm: Calcium Hydroxide

41. Two types: conventional (GI)and light-cured (resin modified- RMGI) Characteristics of glass ionomers: 1) Fluoride release 2) Anti-cariogenicity Mechanism: initial low pH, chemical bonding and the release of the metal cation fluoride 3) Adhesion to enamel and dentin Reduces microleakage (physical exclusion) Cavity Liner-normal thickness <0.5mm: Glass Ionomer

42. Glass Ionomer is based on an acid/base reaction of silicate glass powder (calcium aluminosilicate ) and aqueous polyalkenoic acid (unsaturated carboxylic acid), an ionomer. Cavity Liner-normal thickness <0.5mm: Glass Ionomer

43. Cavity Liner-normal thickness <0.5mm: RMGlass Ionomer Has both acid/base reaction as well as polymerization reaction. Stronger bond to dentin than GI due to mechanical interlocking of polymer in dentin.

44. Consider placing a glass ionomer liner over Dycal such as Vitrebond or Fuji Lining LC. Why? Compressive strength of Dycal is very poor Glass ionomer liner will seal the margins around the Dycal Cavity Liner-normal thickness <0.5mm: Glass Ionomer This means there are two liners, each < 0.5mm in thickness.

45. Dental restorative materials have been developed to provide pulpal protection or prevent pulpal reaction. This is an adaptation of the preparation prior to receiving the final restorative material. Sealers-ideally provide a seamless transition from restoration to tooth structure by providing a protective coating for freshly cut tooth structure of the prepared cavity. Liners-placed with a minimal thickness, less than 0.5mm and provide therapeutic benefit such as fluoride release, dentinal seal through adhesion, and/or antibacterial action that promotes pulpal health. Bases- used as dentin replacement material, allowing for less bulk of restorative or blocking out undercuts for indirect restorations.

46. Materials, most commonly cements, that are used in thicker dimensions beneath permanent restorations to provide for mechanical, chemical, and thermal protection of the pulp. Examples include zinc phosphate, zinc oxide–eugenol, polycarboxylate, and the most common, some type of glass ionomer; usually a resin modified glass ionomer (RMGI) Cavity Base-normal thickness > 0.5mm

47. Thermal Insulation 2 mm dentin (or an equivalent thickness of restorative material) should ideally exist to protect the pulp, but 1-1.5 mm is acceptable Thermal insulation has been found to be directly proportional to the thickness of the insulating material and the structure of the material Cavity Base-normal thickness > 0.5mm

48. Zinc-oxide eugenol and Zinc phosphate cements were once very popular bases, but their use has declined. Bases with eugenol: (Use has also declined) Intermediate Restorative Material (IRM) Temp Bond* Eugenol liquid can inhibit polymerization of resin composite so…don’t use eugenol formulations underneath dentin bonding systems or composite. *Temp Bond NE is non-eugenol containing Temp Bond Cavity Base-normal thickness > 0.5mm

49. Glass ionomers Conventional glass ionomers – Ketac-fil, Ketac-Silver, Miracle Mix Example of a resin-modified glass ionomer is Fuji II LC GIass Ionomer Another RMGI restorative which may be used as a base is Ketac Fill Plus UKCD uses Ketac–fil as temporary restoration Cavity Base-normal thickness > 0.5mm:GI and RMGI

50. Excellent liners/bases because of their ability to chemically adhere to tooth structure Great seal that prevents toxic elements from penetrating into the pulp Excellent seal against bacterial penetration Good biocompatibility when not in direct contact with the pulp Cavity Base-normal thickness > 0.5mm: GI and RMGI

51. Sturdevant’s and Summitt Currently there is no convincing evidence for the routine use of adhesive sealers under metallic restorations, however at UKCD we recommend sealing dentin tubules. Do not remove sound tooth structure to provide space for a base For amalgam or bonded restorations minimize the extent of the base As amount of base material increases bulk of the restorative material is decreased Increase potential for restoration fracture Recommendations for Using Sealers, Liners and Bases

52. UKCD recommendations for amalgam restorations: Shallow preparations Use desensitizing agent ie. Gluma Deep Preparations Liners Dycal (direct pulp cap) Fuji Lining Base: Ketac fil Recommendations for Using Sealers, Liners and Bases

53. Rinse: 2% Chlorhexidine Antibacterial Solution Dentin Desensitizer Recommendations for Using Sealers, Liners and Bases: Shallow amalgam restorations

54. When there is less than ideal dentin protection in one region Rinse: Consepsis Apply liner only at that specific site to provide pulpal medication Glass ionomer(Fuji Lining): fluoride release Recommendations for Using Sealers, Liners and Bases: Moderately deep amalgam restorations

55. Rinse with Consepsis Liner (< 0.5mm) GI or RMGI Base (> 0.5mm) A replacement material for missing dentin E.g. Ketac fil Glass ionomer Restoration Consider using a spherical amalgam such as Tytin (Less condensation pressure) Recommendations for Using Sealers, Liners and Bases: Deep amalgam restorations There may not be need for both

56. When RDT is exatremely small or there is pulp exposure, use CaOH to stimulate reparative dentin formation How thickly should the CaOH be applied? < 0.5 mm of CaOH Recommendations for Using Sealers, Liners and Bases: Deep amalgam restorations

57. Conditions must be favorable for a direct or indirect pulp cap including: 1) Tooth must be vital with no history of spontaneous pain 2) Pain elicited during pulp testing or hot/cold thermal test should not linger after stimulus removal 3) Periapical radiograph should show no evidence of a periapical lesion Direct and Indirect Pulp Cap

58. Indirect pulp cap therapy is preferred over a direct pulp cap Monitor pulpal health for several months. It is not recommended to leave carious material if teeth are to be crowned or serve as abutments for FPD’s or RPD’s. Very deep excavations may contain microscopic pulpal exposures that are not visible to the naked eye. Hemorrhage is the usual evidence of a vital pulp exposure, but with microscopic exposures, such evidence may be lacking. These exposures are large enough to allow direct pulpal access for bacteria and fluids Direct and Indirect Pulp Cap

59. Indirect pulp cap: Procedure Deep carious lesion with no spontaneous pain and vitality tests are normal. This is an attempt to maintain pulpal vitality by placing a material over a small amount of remaining infected dentin. (Removal of this caries may result in a pulpal exposure) 1)Remove wet soft infected dentin near the DEJ 2)Do not remove caries close to the pulp (dry, fibrous demineralized dentin) 3)Place GI or RMGI

60. 4) Restoration: 2 approaches A) Definitive procedure: Place a well-sealed restoration (Remaining bacteria is isolated preventing acid formation and arresting the caries process) B) Step procedure: The tooth is reentered to excavate the remaining caries Additional trauma to the pulp? Risk of pulp exposure (skill of operator) Definitive restoration should be placed to minimize micro leakage Indirect pulp cap: Procedure

61. Several studies: Restored teeth with partial caries removal have equal success compared with teeth with complete caries removal Studies have evaluated indirect pulp cap after 4 to 12 months Lesion color has changed from light brown to dark brown Tissue consistency has changed from soft and wet to hard and dry Streptococcus mutans & Lactobacillus have been reduced to few or zero X-rays : no changes or decrease in radiolucent zone Indirect pulp cap: Procedure

62. Is an attempt to maintain pulpal vitality by placing a material directly over the exposed pulp Small mechanical (non-carious) exposure of a healthy pulp: 1) Field must be isolated with a dental dam 2) Achieve hemostasis (cotton pellet saline) 3) CaOH (gold standard) 4) Place a liner (Fuji lining) or a well-sealed final temporary restoration Direct Pulp Cap: Procedure

63. Carious tooth, asymptomatic ( no indication of pulpal pathology ) symptomatic Short duration Long duration spontaneous endodontics extraction Indirect RMGI pulp cap Temporary fill for 3 mo. Indirect pulp cap RMGI, permanent fill Do not crown CaOH direct pulp cap & RMGI (mechanical exposure) Fill & observe????? For amal.: RMGI if deep. Gluma if shallow. For comp.: etch, prime, bond, RMGI if deep N.V. Pulp testing N.V. Pulp testing Excavate & pulpotomy or ectomy Excavate and fill V. Pulp testing N.V. Pulp testing By C. Rodriguez D.M.D. asymptomatic N.V. Pulp testing

65. Clinical Example of Indirect Pulp Cap