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8/4/2019 Varnish Liners and Bases
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VARNISH, LINERS, and BASES
Stephen C. Bayne
DENT112Conservative Operative DentistrySchool of DentistryUniversity of North Carolina
Roberson TM. Sturdevant's Art and Science of Operative Dentistry ,
4:170-177.
http:// www.dent.unc.edu/ portfolios/ bayne/ dental-materials/
2006, Bayne and Thompson
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OVERVIEWOF PULPAL PROTECTION
1. CHEMICAL Protection 2. PULPAL Medication 3. THERMAL / ELECT Protection 4. MECHANICAL Protection
PROBLEM = No perfect replacement for missing enamel and dentin.
1. SOLUTION LINER = thin film (varnish, bonding system, dentin sealer) 2. Suspension Liner (20-25 mm) 3. CEMENT LINER = medium thickness (100-500 mm)
4. CEMENT BASE = thick (500-1000 mm)
NORMAL
RESTORED
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PULPALPROBLEMS:
Fluid Flow Microleakage
FLUID FLOW = J = (P) (r4) / (8) (h) (l)
Occlusion of
tubules
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CHEMICAL PROTECTION
DEFINITIONS:Varnish = thin film solution liner (hydrophobic)Suspension liner = thin film aqueous liner (hydrophilic)Bonding system = thin film solution liner (hydrophilic)Dentin sealer = thin film solution liner (hydrophilic)
COPALITE = 90% solvent + 10% copal resin
• Hydrophobic and does not wet dentin well.• Requires 2 applications for 85% coverage.• Thin coats work best.
Copalite
Smear Layer on Dentin
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DENTINFUNCTIONS:
Chemical Protection Thermal / Electrical Protection Biological Protection (Medication) Mechanical Protection
PULPALPROBLEMS:
Fluid Flow Microleakage
PULPAL MEDICATION(Biological Protection)
RDT
1º Dentin2º Dentin
3º Dentin
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DENTINFUNCTIONS:
Chemical Protection Thermal / Electrical Protection Biological Protection (Medication) Mechanical Protection
PULPALPROBLEMS:
Fluid Flow Microleakage
PULPAL MEDICATION(Biological Protection with Eugenol or Calcium Hydroxide)
and ZnO ( Zn++)
• pH = 11.0• Low strength• Ca ion + salicylate
Ca(OH)2 StimulatingEugenol
Palliative
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THERMAL PROTECTION
Intraoral HEAT FLOW:Normal thermal transient = 30-60s at 5-60°CHEAT paths = through restoration or via microleakagePulpal temperature = f ( TIME, TEMP, THICKNESS )
T0
Amalgam Dentin PulpT3
T2
T1
T0
+T
+Q
-Q
T3
Amalgam Dentin Pulp
T3
T2
T1
T0
+t+Q
Throughrestoration:
Thermal Conductivity Thermal Diffusivity
Amalgam
Tooth
Aroundrestoration:
Thermal Expansion
RDT
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MECHANICAL PROTECTION
PROTECTION = 1-2 mm (1000-2000 mm)
> Chemical Protection (Sealed tubules)> Biological Protection (Pulpal Medication)> Thermal / Electrical Protection (1-2 mm)> Mechanical Protection (BASE = 1-2 mm)
RMGI
Polycarboxylate
Zinc Phosphate
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BASES
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COMMERCIAL EXAMPLESof Varnishes, Liners, and Bases
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PROCEDURE SUMMARYfor Medicament, Liner/Base, Varnish/Sealer/DBS
RDT =
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