8.Oral Cavity Considerations in Dental Materials.pptx

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1. بسم الله الرحمن الرحيم

2. كل عام وانتم بالف الف خير 4/12/2025 2

3. Lecture Title: Oral Cavity Considerations in Dental Materials 4/12/2025 3

4. 1-Biocompatibility Biocompatibility refers to the ability of dental materials to function within the oral environment without causing adverse local or systemic effects. Key considerations: Dental Implant 4/12/2025 4

5. 1-Biocompatibility ISO Standards : Materials must pass cytotoxicity, sensitization, and implantation tests. . ISO - International Organization for Standardization Dental Implant 4/12/2025 5

6. 1-Biocompatibility Common Concerns Nickel (in alloys) may trigger hypersensitivity; residual monomers in resins (e.g., BPA derivatives) can leach and irritate pulp. . Dental Implant 4/12/2025 6

7. 1-Biocompatibility Host Response : Chronic inflammation or immune reactions may arise from poorly tolerated materials. Alternatives like titanium implants or zirconia crowns are preferred for sensitive patients. Dental Implant 4/12/2025 7

8. Biomechanics Dental materials must mimic natural tooth mechanics to withstand functional loads. Dental Implant 4/12/2025 8

9. Biomechanics Dental materials must mimic natural tooth mechanics to withstand functional loads. Stress Distribution Occlusal Forces Fatigue Resistance Dental Implant 4/12/2025 9

10. Biomechanics Dental materials must mimic natural tooth mechanics to withstand functional loads. Stress Distribution : Materials with a high modulus of elasticity (e.g., amalgam) resist deformation but may cause stress surrounding teeth. Composites flex similarly to dentin, reducing fracture risk. Dental Implant 4/12/2025 10

11. Biomechanics Dental materials must mimic natural tooth mechanics to withstand functional loads. Occlusal Forces : Molars endure ~600–1200 N; materials must balance strength (e.g., metal alloys) and resilience (e.g., reinforced composites). Dental Implant 4/12/2025 11

12. Biomechanics Dental materials must mimic natural tooth mechanics to withstand functional loads. Fatigue Resistance : Cyclic loading during chewing demands materials with high fatigue limits (e.g., lithium disilicate ceramics). Dental Implant 4/12/2025 12

13. Force and Stress Types of Forces: Stress Concentration: Design Principles : Dental Implant 4/12/2025 13

14. Force and Stress Types of Forces : Compressive (e.g., biting), tensile (e.g., pulling), and shear (e.g., grinding). Dental Implant 4/12/2025 14

15. Force and Stress Types of Forces : Compressive (e.g., biting), tensile (e.g., pulling), and shear (e.g., grinding). Stress Concentration : Sharp margins or thin restorations amplify stress, leading to fractures. Rounded contours and adequate bulk minimize failure. Design Principles : Avoid sharp angles; use adhesive techniques to distribute stress evenly Dental Implant 4/12/2025 15

16. Force and Stress Types of Forces Stress Concentration Design Principles Dental Implant 4/12/2025 16

17. Force and Stress Stress Concentration : Sharp margins or thin restorations amplify stress, leading to fractures. Rounded contours and adequate bulk minimize failure . Dental Implant 4/12/2025 17

18. Force and Stress Design Principles Avoid sharp angles; use adhesive techniques to distribute stress evenly Dental Implant 4/12/2025 18

19. Galvanism Electrochemical reactions between dissimilar metals (e.g., amalgam and gold) in saliva create galvanic currents. Effects : Metallic taste, pain, or accelerated corrosion. Prevention : Use single-metal systems or non-metallic materials (e.g., ceramics, composites). Dental Implant 4/12/2025 19

20. Moisture and Acid Levels Saliva : pH Challenges : Xerostomia : Dental Implant 4/12/2025 20

21. Moisture and Acid Levels Saliva : Moisture compromises adhesion; hydrophobic bonding agents (e.g., resin cements) improve retention. Dental Implant 4/12/2025 21

22. Moisture and Acid Levels pH Challenges : Oral pH fluctuates (4.5–7.5). Acidic environments demineralize enamel and degrade materials (e.g., glass ionomers release fluoride to buffer acids). Dental Implant 4/12/2025 22

23. Moisture and Acid Levels Xerostomia : Reduced saliva increases caries risk; moisture-tolerant materials (e.g., resin-modified glass ionomers) are preferred. Dental Implant 4/12/2025 23

24. Temperature Thermal Expansion : Conductivity : Dental Implant 4/12/2025 24

25. Temperature Thermal Expansion : Mismatch between material and tooth (e.g., amalgam > enamel) causes microleakage. Low-expansion ceramics (e.g., zirconia) are ideal. . Dental Implant 4/12/2025 25

26. Temperature Conductivity : Metallic restorations conduct heat/cold, requiring insulating bases (e.g., RMGI) to protect pulp. Dental Implant 4/12/2025 26

27. Retention Mechanical Retention : Chemical Retention : Dental Implant 4/12/2025 27

28. Retention Mechanical Retention : Undercuts, grooves, or surface roughness (e.g., etched enamel for composite bonding). . Dental Implant 4/12/2025 28

29. Retention Chemical Retention : Adhesive systems (e.g., phosphoric acid etching, dentin bonding agents) enhance micromechanical interlocking. Dental Implant 4/12/2025 29

30. Microleakage Causes : Gap formation at restoration margins allows bacterial infiltration, leading to secondary caries. Dental Implant 4/12/2025 30

31. Microleakage Prevention : Optimal polymerization shrinkage control (e.g., incremental layering of composites), flowable liners, and adhesive systems with hydrophobic sealing. Dental Implant 4/12/2025 31

32. Allergic Responses Common Allergens : Symptoms : Management : Dental Implant 4/12/2025 32

33. Allergic Responses Symptoms : Mucosal erythema, lichenoid reactions, or systemic dermatitis. Dental Implant 4/12/2025 33

34. Allergic Responses Management : Allergy testing; alternatives like hypoallergenic polymers (e.g., PEEK) or noble metal alloys Dental Implant 4/12/2025 34

35. Conclusion Successful dental treatments require harmonizing material properties with the dynamic oral environment. Biocompatibility, biomechanical performance, and resistance to thermal/chemical challenges are critical. Clinicians must prioritize patient-specific factors (e.g., allergy history, occlusal loads) to optimize restoration longevity and safety . Dental Implant 4/12/2025 35

36. Thanks Dental Implant 4/12/2025 36

37. كل عام وانتم بالف الف خير