Denture base Dr Safaa Kamel.pdf

The Denture Base and Artificial teeth Dr. Safaa Kamel Lecturer of Prosthodontic, Faculty of dentistry, Cairo University  The Component Parts of Removable Partial Dentures Denture Base Connectors: Artificial Teeth Major Connectors M...

The Denture Base and Artificial teeth Dr. Safaa Kamel Lecturer of Prosthodontic, Faculty of dentistry, Cairo University  The Component Parts of Removable Partial Dentures Denture Base Connectors: Artificial Teeth Major Connectors Minor Connectors Supporting Rests Retainers: Direct retainers Indirect Retainers  The Component Parts of Removable Partial Dentures 1- Denture Base Definition It is that part of the denture, which rests on the foundation tissues and to which artificial teeth are attached. It helps in transferring Occlusal stresses to the supporting oral structures Types of Denture Bases 1-Bounded-Partial Denture Bases 2- Free-end Partial Denture Bases (Distal-extension Base)  Bounded Denture Bases It covers an edentulous span between 2 abutments, it restore short or long span edentulous area  Free-end Partial Denture Bases (Distal-extension Base) The base is bounded by a natural tooth on one side the other side is free Free-end Partial Denture Bases (Distal-extension Base) Functions of the Denture Base 1- Carries the artificial teeth 2- Transfers Occlusal stresses to the supporting str. stimulation by massage of the tissues 3- Provides support 4- Provides denture retention by physical means 5- Prevent Migration and Over Eruption of the Remaining Teeth  Functions of the Denture Base 5- Provides denture bracing 6- Provides stabilization against tipping of the distal-extension dentures Stabilization Is the Resistance of Partial Denture to Tipping (Rocking)  Tipping (Rocking) Is the Rotation of Partial Denture around a Fulcrum Requirements of an Ideal D. B. Material 1- Accuracy of adaptation to the tissues 2- Sufficient strength 3- Should have low specific gravity, 4- Biological acceptability,maintain good finish 5- Potential for future relining 6- Should allow thermal conductivity necessary for tissue stimulation. 7- Can easily be kept clean 8- Esthetically acceptability 9- Low initial cost  Denture Base Material Metallic Nonmetal Combined metallic. And non met. D.B Denture Base Material Metallic Bounded saddle cases as cobalt chromium alloy Combined metallic And non met. D.B. Free end saddle cases  Denture Base Material Non Metal As Acrylic Resin (Temporary Acrylic Removable Partial Dentures)  Metallic denture base Advantages 1- More Rigid Than Resin Bases Even in Thinner Section 2- Less Bulky (thinner sections) 3- Greater Thermal Conductivity 4- Fit More Accurately to Underlying Tissues 5- More Hygienic as the fitting surface is Polished and non-porous with less Tendency for Food Accumulation  Disadvantages of Metal Bases 1-Difficult to Rebase or Reline When Ridge Resorption Occurs 2- Difficult to Repair 3- The Colour of Metal Bases Does Not Simulate the Natural Appearance of Oral Tissues  Non-metallic, Acrylic Resin Denture Bases Advantages 1- Eesthetically is Satisfactory due to Its Pink Colour 2- Light in Weight 3- Easy to Reline, Rebase or Repair 4- Needs Simple Processing Procedures Disadvantages of Resin Base 1- Weak, Have Low Tensile Strength, Brittle And Are Liable To Fracture 2- To Attain Enough Strength, Resin Bases are Made Bulky 3- Have Low Thermal Conductivity 4- The fitting surface is porous and not polished bad oral hygiene, bad odour and inflammation of the tissues INDICATIONS OF RESIN BASE 1-Age and time 2-During healing process after extraction 3-Cost Combined metallic and acrylic RESIN BASE…future relining 1- Free-end Saddle Cases 2- Increased Rate of Bone Loss As Diabetic Patients or Patients on Steroid Therapy 3- Cases With Extreme Bone Loss. The Presence of Acrylic Resin Is Necessary to Restore the Original Contour ✓ Methods of attaching denture base ✓ Tissue stops ✓ Finish line  Methods of attaching denture base Most commonly, Ladderlike pattern and closed meshwork configuration  Methods of attaching denture base Most commonly, Ladderlike pattern and closed meshwork configuration  Methods of attaching denture base Extension of minor connector forming distal extension base  Tissue stops to determine acrylic resin thickness Essential parts in he fitting surface of minor connectors,2 or 3 made on the master casts Tissue stops to determine acrylic resin thickness  finishing lines They are butt joints at the junction of major connector with denture base made on external and internal surfaces of major connector. free end and short bounded saddle..internal and external Internal finish line Internal finish line External finish line  Denture Base Extension (Maximum coverage) 1- Buccally 2- Lingually 3- Posterior Limit tuberosity and pad 4- Anterior Limit Denture Base Extension Antero- posterior Denture Base Extension Buccally-Lingually until mucosal reflection and muscle function Max. Denture Base Extension POSTERIORLY PALATALLY LABIALLY The concave Polished Surface Contour  Relationship of Denture Base to Abutment 1- Close contact with gingival margin relief to avoid trauma 2- Open Contact to create cleansable area…small space should be avoided..caries,,gingivitis Relationship of Denture Base to Abutment Relationship of Denture Base to Abutment Artificial teeth  Tooth material Artificial teeth may be made of: 1. Acrylic resin 2. Porcelain 3. Metal 4. Combination between acrylic resin and metal 5. Cross-linked acrylic resin. 6. Recently Isosit (a mix of composite and resin) PROPERTY ACRYLIC PORCELAIN Composition Acrylic resin Porcelain mat. Attachment Chemical Mechanical Weight Lighter Heavier Sound Natural Clicking Appearance Natural Natural Color stability Less More Liable to Less liable to Distortion distort by distortion temperature PROPERTY ACRYLIC PORCELAIN Abrasion R. Low High Crazing Affected by Not affected organic solvents Brittleness Brittle Very brittle Resiliency More resilient Less resilient Modification easily modified Difficult Indications * small interarch * normal distance interarch space. * Flat/ Flabby R. * normal well developed R. Thank You  Acrylic resin teeth Properties of acrylic resin teeth: 1. Low sp. Gravity 2. Chemical union with acrylic denture bases 3. Less noisy 4. Easily modified by grinding 5. Less harmful to the underlying tissues due to their resiliency 6. Low abrasion resistance 7. Can be used in small inter-arch distance  Porcelain teeth They need mechanical means of retention pins for anterior teeth and holes for posterior teeth Properties of porcelain teeth 1. Mechanical means of retention 2. Heavier in weight 3. Noisy in use 4. Cant be modified 5. High abrasion resistance 6. Very brittle