Composite

Composite generally means composite material created by the artificial joining of simpler materials. A composite material acquires properties that its individual components do not have by combining them. In dentistry, composite refers to a filling material composed of glass and a resin binder.

Composition[edit | edit source]

Filler - glass (Sr, Ba), SiO₂, Al₂O₃, B₂O₃, phosphates, pigments. ^[1]
Binder - resin - monomers and copolymers (BisGMA - bisphenolglycidyl methacrylate, UDMA - urethane methacrylate, TEGMA - triethylene glycol methacrylate), self-solidification inhibitors, initiation system and stabilizers. ^[1]
Auxiliary elements - silane - ensures the connection of filler and binder.

Properties[edit | edit source]

Composite belongs to aesthetic filling materials. Holds microretention in the cavity. This means that the surface of the cavity must first be etched in order for the composite filling to have sufficient retention. The composite should be stored hermetically sealed in a cool (5-8 °C) and dark place.

Advantages

excellent aesthetics;
perfect polishability and color fastness;
excellent adhesion to enamel;
acid resistance;
resistance to chewing pressure;
high toughness.

Disadvantages

contraction leading to fractures in the enamel or joints between the filling and enamel;
poor adhesion to dentin;
missing anticariogenic properties;
sensitivity to processing and technological procedures;
poor removability;
possible allergic effects.

Classification[edit | edit source]

According to the method of polymerization

photocomposite;
chemically setting (paste/paste);
dual setting - fixation cements, building materials (bulk fill).

According to the size of the filler particles

conventional – particle size 15–100 μm;
microphilic – particle size 0.01–0.04 μm;
hybrid – a mixture of three different particle sizes (both of the previous ones and particles with a size of 1-50 μm).

Flow composite, before and after filling the cavity.

According to the amount of filler

up to fifty percent it is not a composite;
highly charged;
slightly filled - so-called flow composites.

Indication[edit | edit source]

fillings I., II., III., IV. and Class V according to Black of small and medium extent, under conditions of good hygiene and localization supragingivally
wedge-shaped defects of the neck area
correction of the shape of the teeth

Contraindications[edit | edit source]

poor oral hygiene of the patient
bruxism
if the cavity or part of it is located subgingivally
if it is impossible to ensure a dry and clean work area

Processing and Application[edit | edit source]

For more information see Making composite filling.

The photocomposite is applied in small layers (batches), each of which is polymerized. Small layers are used to avoid large volume contraction which is undesirable (the resulting hermetic edge seal might not form (in this case most certainly)).

Etching
- Enamel 30 s
- Dentin 10 s
Rinsing
Drying (light, do not dry)
Primer
- Massage for 30 seconds
Blowing
Bond
- Polymerize
Application of individual small increments until the final appearance with continuous polymerization.
Finishing, articulation
Polishing