Prosthetic teeth: Resin and Porcelain teeth.pptx

Comparison between prosthetic resin teeth and porcelain teeth

1. PROSTHETIC DENTURE TEETH: Materials, Properties, And Clinical Considerations Presented by: OFAMBA JOSHUA 22/U/6772 1

2. Objectives Describe materials used in the fabrication of prosthetic teeth Compare the properties of porcelain and resin teeth 2

3. Outline Introduction to Prosthetic Denture Teeth Wear Resistance Materials Used General Requirements Methacrylate Resin Teeth Porcelain Teeth Composite Resin Teeth Porcelain vs Resin teeth Clinical Guidelines for Material Selection 3

4. Introduction to Prosthetic Denture Teeth Definition and Purpose Prosthetic or denture teeth are artificial teeth used in denture fabrication Available in variety of molds and shades to meet patient needs Primary functions: Restore masticatory functions (chewing, biting, shearing, crushing food) Provide superior esthetics 4

5. Wear Resistance! - The Deal Breaker 5

6. Clinical Importance of Wear Resistance Important requirement for acceptance and selection of prosthetic teeth High wear resistance is crucial for denture longevity Individual variation in wear patterns due to complex interaction of factors T he ability of the artificial tooth material to withstand surface loss and maintain form and function under masticatory and parafunctional forces over time. Definition 6

7. Effects of Poor Wear Resistance Wear of occluding surfaces Loss of vertical dimension of occlusion (VDO) Alteration in functional pathways of masticatory movements Fatigue of the muscles of mastication Contributing Factors to Wear Mechanical factors pH levels Erosion and corrosion processes Parafunctional habits Nutritional habits 7

8. Materials used in the Fabrication of Prosthetic Teeth 8

9. Mainly Two Materials are Used: 2. Porcelain Vacuum-fired porcelain 1. Resins Methacrylate Resins - Poly(methyl methacrylate) (PMMA) based Modified Methacrylate Resins Multiplex Polymer Matrix (MPM) resin teeth Interpenetrating Polymer Network (IPN) resins Double Cross-Linked (DCL) resins Vinyl Resins Composite Resins 9

10. General Requirements for Prosthetic Teeth A. Mechanical Properties: 1. Structural Integrity Durable bond with denture base material - prevents detachment High impact strength - withstands mastication forces without fracture No permanent deformation under masticatory forces - ensures stable occlusal contacts 2. Thermal and Chemical Resistance High heat-distortion temperatures - prevents permanent deformation Resistance to oral fluids/solvents - maintains integrity in oral environment 10

11. cont’d B. Functional & Esthetic Properties: 1. Wear Resistance Requirements High abrasion resistance with little or no wear Maintenance of predetermined vertical dimension of occlusion Resistance to parafunctional movements 2. Esthetic Requirements Esthetically pleasing and inconspicuous - natural blend Adequate translucency - mimics natural teeth Color stability - maintains appearance over time Good surface texture - realistic feel and appearance 11

12. cont’d 3. Clinical Handling Requirements Esthetically pleasing and inconspicuous - natural blend Adequate translucency - mimics natural teeth Color stability - maintains appearance over time Good surface texture - realistic feel and appearance 12

13. Methacrylate Resin Teeth -Mr. Popular 13

14. Primary Material and Manufacturing Primary Material: Poly(methyl methacrylate) (PMMA) Manufacturing Techniques: Compression molding dough technique Injection molding Advanced Formulations for Improved Performance Multiplex Polymer Matrix (MPM) resin teeth I nterpenetrating P olymer N etwork ( IPN ) teeth Double Cross-Linked (DCL) resins 14

15. IPN Teeth Advantages Popular choice due to excellent properties: Good esthetics Low creep and flow rates High wear resistance Minimum dissolution in solvents Effective bonding to resin bases Cross-linking Benefits Improved heat-distortion temperatures Enhanced strength and resistance to crazing in coronal portion 15

16. Advantages 16

17. 1. Chemical Bonding Clinical Benefits Prevents capillary spaces around teeth (difficult to clean, harbor microorganisms) Facilitates grinding to accommodate interocclusal spaces Allows reshaping for esthetic purposes without destroying bond Optimized Design for Bonding Highly cross-linked coronal portion for strength Little/slight cross-linking in gingival portion for improved bonding 17

18. 2. Esthetic Significantly improved esthetic qualities over years Clinically acceptable appearance Layered construction: Different colors with lighter shades towards incisal /occlusal portions Enhanced translucency through color layering Custom tinting capability with resin bases for natural esthetics 18

19. 3. Functional Easy occlusal reshaping/grinding for desired articulation Versatile adjustment for various occlusal schemes Ridge-lap areas easily ground without compromising tooth-resin bond 19

20. 3. Mechanical and Physical Superior Mechanical Properties High resiliency and toughness compared to porcelain Less liable to fracture or chip on impact Good resistance to thermal shocks Insoluble in oral fluids Improved Generations show: More wear resistance than earlier ones Reduced staining Better dimensional stability 20

21. Disadvantages 21

22. 1. Wear Resistance ( Primary Disadvantage! ) Lower abrasion resistance than porcelain Leads to VDO changes in long-term wearers Less dimensionally stable in water 2. Trade-offs from Improvement Efforts Inorganic fillers improve wear resistance But increase microbial biofilm adhesion Unfilled and IPN teeth do not promote adhesion 3. Earlier Generation Issues Non-cross-linked teeth: soften in solvents, discolor, low heat-distortion temps Cross-linking improved these properties 22

23. 4. Bonding failure issues Cause detachment from denture bases attributed to multiple factors: Surface Contamination Issues Impurities (e.g., wax) on ridge-lap areas Contamination with tinfoil substitutes Inadequate chemical/mechanical preparation of tooth surfaces Material Property Mismatches Water sorption of resins Differences in coefficient of thermal expansion 23

24. Essential steps for adequate bonding 1. Wax Elimination and Cleaning Flush mold and teeth with boiling water after wax removal Steam cleaning or mild detergent recommended 2. Surface Treatment Protocol Roughen glossy ridge-lap areas (e.g., sand-blasting) Wet with monomer before resin application Benefits: Improves bond strength and micromechanical retention Optimizes surface energy for adhesion 3. Material Compatibility Use compatible combinations of denture base resins and teeth Reduces risk of bond failures 24

25. Porcelain Teeth -The Elegant Veteran 25

26. Composition and Manufacturing Historical Context and Availability Largely replaced by methacrylate resins in recent decades Still available as individual teeth or full sets Wide range of shades and molds offered Composition – Triaxial Ceramic Mainly feldspar Quartz (≈15%) Kaolin (≈4%) for moldability Manufacturing Process Formed in split metal molds Vacuum-fired in high-temperature ovens Glazed for surface finish Slowly cooled to prevent crazing 26

27. Advantages 27

28. 1. Superior Esthetic Properties Natural-like Optical Characteristics: Internal color blending through translucent enamel layers Progressive color variation from incisal to gingival areas and across different teeth Natural translucency allows light reflection, refraction, and pickup Long-term Esthetic Stability: Excellent color stability over time Maintains natural optical characteristics 28

29. 2. Mechanical and Physical Superior Wear Resistance: High abrasion resistance (10–20× greater than resin teeth) Maintains vertical dimension of occlusion (VDO) Hard material with minimal wear Excellent Mechanical Properties Dimensionally stable and hard No permanent deformation under occlusal load High heat-distortion temperatures Chemical Resistance and Clinical Benefits Insoluble in oral fluids and most solvents Allows denture rebasing without tooth replacement 29

30. Disadvantages 30

31. Attached via pins or diatoric holes only Posterior teeth:  Retained by acrylic resin filling diatoric holes within the teeth. Anterior porcelain teeth:  Retained by acrylic resin surrounding their retention pins. Limits grinding or reshaping in tight interarch spaces Creates capillary spaces that are hard to clean and may harbor microorganisms 31 1. Mechanical Attachment Method ( Primary Disadvantage!)

32. Clinical Consequences of mechanical attachment Higher risk of detachment from resin bases Difficult positioning and retention in limited interarch spaces Very limited ability to reshape cervical areas 32

33. 3. Wear Effects on Opposing Surfaces Causes significant wear of opposing enamel or metallic occlusal surfaces Not suitable for single complete dentures opposing natural teeth or gold crowns 4. Mechanical Limitations Brittle; prone to cracking or chipping on impact Occlusal adjustments are difficult: grinding removes surface glaze, polishing is hard 5. Clinical Comfort and Practical Issues Produces clicking sounds during function Higher density → heavier dentures Thermal expansion mismatch with resin → internal stresses Less resistant to thermal shocks than resin teeth 33

34. Bonding Enhancement Techniques Overcoming Mechanical Attachment Limitations Goal: Improve bond with methacrylate resin bases Achieved via micromechanical retention and chemical bonding Bonding Enhancement Procedure Step 1: Surface Etching Treat ridge-lap area with hydrofluoric acid gel Step 2: Chemical Coupling Apply silane coupling agent to enable chemical bonding with resin base 34

35. Composite Resin Teeth - An Advanced Alternative 35

36. Introduction and Development Introduced in 1980s as suitable denture tooth material Composition improvements in organic and inorganic components Addition of microfine and nanofiller particles (e.g., silica) Nanofilled Composite Properties Clinically acceptable mechanical and physical properties: High wear resistance Good strength Good surface finish 36

37. Unique Mechanical Behavior Fillers act as binding agents creating internal cavities Large-scale plastic deformation under impact forces Significantly increased fracture toughness Absorb mastication stresses effectively High elastic modulus ensures light, well-distributed pressure transmission Clinical Advantages Significantly less wear to opposing enamel surfaces than both resin and porcelain Material of choice for single complete dentures opposing natural dentition 37

38. Resin Vs Porcelain -A tight match! 38

39. Property Resin Teeth Porcelain Teeth 1. Attachment to Base Chemical bond – excellent integration Mechanical via pins/holes – creates gaps 2. Mechanical Durability High resilience & toughness; less brittle Very brittle; chips/cracks on impact 3. Wear Resistance Lower abrasion resistance; VDO reduction possible Excellent – 10–20× greater than resin; maintains VDO 4. Effect on Opposing Teeth Compatible with natural teeth/metal surfaces Causes significant wear to enamel/metal 5. Clinical Adjustability Easy grinding/reshaping of all areas Difficult adjustment; glaze loss; limited reshaping 6. Esthetic Properties Excellent; layered colors; characterizable Superior optical properties; natural translucency 39

40. Property Resin Teeth Porcelain Teeth 7. Sound on Contact Silent operation – natural feel Noisy clicking with opposing porcelain 8. Chemical Stability Insoluble; some dimensional changes in water Completely insoluble; dimensionally stable 9. Thermal Properties Good thermal shock resistance; improved heat distortion High heat distortion; less thermal shock resistance 10. Clinical Applications Versatile – most situations; easy repair Limited – avoid opposing natural teeth 11. Longevity Factors Moderate wear over time; bond failures possible Excellent longevity if no fracture occurs 40

41. Critical Clinical Guidelines -Dos and Don’ts 41

42. Material Selection Principles Avoid Incompatible Combinations CRITICAL WARNING! Never combine posterior resin teeth with anterior porcelain teeth in complete dentures Scientific Rationale: Significant differences in abrasion resistance Resin wears more rapidly than porcelain Creates destructive occlusal forces in anterior region Clinical Consequences of Improper Combination Anterior ridge resorption Prosthesis instability Compromised function and comfort 42

43. Best Practice Recommendations Material Compatibility Select compatible denture base resins and teeth combinations Minimize bond failures through proper selection Ensure overall denture stability Clinical Decision Making Consider patient factors: Bite force, parafunctional habits, opposing dentition Evaluate interarch space limitations Plan for long-term maintenance and adjustments Choose materials based on clinical evidence and patient needs 43

44. Reference: Zarb , George A., John Hobkirk , Steven Eckert, and Rhonda Jacob. Prosthodontic Treatment for Edentulous Patients: Complete Dentures and Implant-Supported Prostheses . 13th ed. St. Louis: Elsevier, 2012. 44