Composites

Definition and Overview: Composites are materials composed of two or more distinct components that, when combined, exhibit superior properties compared to their individual constituents.

Composite Resin: Versatile restoration material used in dentistry.
Glass Ionomer Cement: Bonds chemically to tooth structure and releases fluoride.
Resin-Modified Glass Ionomer Cement: Combines features of glass ionomer and composite technology.
Compomer: Hybrid of composite resin and glass ionomer used primarily in pediatric dentistry.

Advantages:
- Aesthetics: Ability to closely match natural tooth color.
- Adhesion: Bonds well to tooth structure providing mechanical support.
- Versatility: Can be used in various situations including anterior and posterior restorations.
Disadvantages:
- Wear Resistance: Less durable compared to amalgam.
- Polymerization Shrinkage: May lead to gaps or sensitivity post-placement.

Chemical-Cured Composite Resins:
- Process: Involves a chemical reaction that hardens the resin.
- Timing: Set time is predetermined by the material's formulation.
Light-Cured Composite Resins:
- Process: Hardening prompted by exposure to a specific wavelength of light, usually blue light.
- Benefits: Control over the working time; immediate set.
Dual-Cured Composite Resins:
- Process: Combination of both chemical and light curing mechanisms.
- Use Case: Ideal for areas difficult to light-cure directly.

Fillers: Inorganic particles added to the resin to enhance various properties.
Impact on Properties:
- Increases strength and wear resistance.
- Alters aesthetic properties including translucency and opacity.

Biocompatibility: Non-toxic and compatible with oral tissues.
Strength: Ability to withstand occlusal forces.
Wear Resistance: Critical for posterior restorations subject to abrasion.
Polymerization Shrinkage: Shrinkage that occurs upon curing which can affect restoration integrity.
Thermal Conductivity: Amount of heat transfer through the material.
Coefficient of Thermal Expansion: Measures how the material expands or contracts with temperature changes.
Water Sorption: Ability to absorb moisture, which can affect longevity.
Elasticity: Ability to deform under stress and return to original shape.
Radiopacity: Visibility on X-rays; important for detecting secondary caries.

Recommendation: Incremental application minimizes shrinkage and maximizes adaptation.
Factors for Light-Curing Time: Thickness of increments, type of resin, and light characteristics should be considered when determining curing times.

Sectional Matrix for Class II Composite: Proper placement technique of a matrix band to ensure margin adaptation.
Shade Selection Process: Importance of selecting the right shade based on hue, chroma, and value; influences esthetic outcome of the restoration.
Finishing & Polishing: Essential for achieving smooth margins and surface integrity post-restoration.

Storage Considerations: Protective environment essential to maintain material integrity, including shelf life concerns and contamination control.

Use Cases: Restorations, aesthetic applications, and their integration into clinical practice.
Selection Considerations: Shade selection influenced by available lighting conditions and shade guides. Ensuring patient satisfaction through proper matching.
Matrix Systems & Light-Curing Factors: Understanding the handling of matrix systems and the importance of light-curing techniques.

Common Issues:
- Fracture of restoration due to excessive occlusal forces.
- Recurrent caries potentially stemming from marginal leakage or poor bonding.
- Operator error can compromise placement technique effectiveness.

Definition: Materials processed in a lab or chairside that cater to more complex restorations such as crowns or inlays.
CAD/CAM Technology: Integration of computer-aided design and manufacturing into indirect restoration methodologies.