Hybrid Dental Composites Biomechanical Properties

Hybrid Dental Composites Biomechanical Properties

Write a short note on hybrid composite resin.
Answer:

Hybrid Composite Resin:

The latest category of composite is the hybrid. These were to be developed so as to obtain better surface smoothness than that of the small particle, but yet maintain the properties of the latter. The hybrid composites have a surface smoothness and esthetics competitive with microfilmed composites for anterior restoration.

Composition of Hybrid Composite Resin:

1. Two kinds of filer particles are employed:
2. Colloidal silica: Present in higher concentration.
3. Heavy metal glasses: Average particle size is 0.6 to 1 mm.
4. Filler content: 75–80 wt% or 60–65 volume%.

Properties Hybrid Composite Resin:

The properties range between conventional and small particles.

They are gradually superior to microfiler Compressive strength:

• It is slightly less than that of small particle composite (i.e. 240 to 290 MPa).
• Tensile strength: Comparable to small particles (i.e. 30 to 55 MPa).
• Elastic modulus: It ranges between that of conventional and microfiled composites (7 to 12 GPa).
• Coefficient of thermal expansion: Though CTE is high (30-40 × 10^-6/°C) it is still less than that of microfiled.
• Water sorption: It corps less water than the microfiled resin (i.e. 5 to 17 mg/mm²).
• Esthetics: The surface smoothness and esthetics is competitive with microfilled composite for anterior restoration.
• Radiopacity: The presence of heavy metal glasses makes the hybrid more radiopaque than enamel. It is 2 to 5 mm, Al.

Clinical Consideration / Indication:

• The hybrid composite is widely used for anterior restorations including class IV because of its smooth surface and good strength.
• The hybrids are also being widely employed for stress-bearing restorations in class II restoration.